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Thorapalli, Muralidharan Seshagopalan, and Ruihao Zhu. "Continuum Actuator Based Soft Quadruped Robot." Thesis, KTH, Mekatronik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-286348.
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Quadruped robots can traverse a multitude of terrains with greater ease when compared to wheeled robots. Traditional rigid quadruped robots possess severe limitations as they lack structural compliance. Most of the existing soft quadruped robots are tethered and are actuated using pneumatics, which is a low grade energy source and lacks viability for long endurance robots. The work in this thesis proposes the development of a continuum actuator driven quadruped robot which can provide compliance while being un-tethered and electro-mechanically driven. In this work, continuum actuators are developed using mostly 3D printed parts. Additionally, the closed loop control of continuum actuators for walking is developed. Linear Quadratic Regulator (LQR) and pole placement based methods for controller synthesis were evaluated and LQR was determined to be better when minimizing the actuator effort and deviation from set-point. These continuum actuators are composed together to form a quadruped. Gait analyses on the quadruped were conducted and legs of the quadruped were able to trace the gaits for walking and galloping.Fyrfotarobotar kan lättare korsa en mängd olika terränger jämfört med hjulrobotar. Traditionella styva fyrfotarobotar har kraftiga begränsningar då de saknar strukturell följsamhet. De flesta befintliga mjuka fyrbenta robotar är kopplade till en eller flera kablar och drivs av pneumatik, vilket är en lågkvalitativ energikälla och lämpar sig inte för robotar med lång uthållighet. Arbetet i denna avhandling föreslår utvecklingen av en continuum ställdonsdriven fyrfotarobot, som ger följsamhet samtidigt som den ¨ar frånkopplad och elektromekaniskt driven. I detta arbete framställs continuum ställdon med mestadels 3D-printade delar. Dessutom utvecklas dessa ställdons slutna kontrolloop för gång. Linjärkvadratisk regulator (LQR) och metoder baserade på polplacering utvärderades för styrsyntes, och det fastställdes att LQR presterade bättre när man minimerar ställdonets ansträngning samt avvikelse från referensvärde. Continuum ställdon sammansattes för att bilda en fyrbent robot. Gånganalyser utfördes på roboten och dess ben kunde följa gång- och galopprörelser.
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Al, Abeach L. A. T. "Pneumatic variable stiffness soft robot end effectors." Thesis, University of Salford, 2017. http://usir.salford.ac.uk/44183/.
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Traditionally, robots have been formed from heavy rigid materials and have used stiff actuator technologies. This means they are not well suited to operation near humans due to the associated high risk of injury, should a collision occur. Additionally, rigid robots are not well suited to operation in an unstructured environment where they may come into contact with obstacles. Furthermore, traditional stiff robots can struggle to grasp delicate objects as high localised forces can damage the item being held. The relatively new field of soft robotics is inspired by nature, particularly animals which do not have skeletons but which still have the ability to move and grasp in a skilful manner. Soft robotics seeks to replicate this ability through the use of new actuation technologies and materials. This research presents the design of a variable stiffness, soft, three-fingered dexterous gripper. The gripper uses contractor pneumatic muscles to control the motion of soft fingers. The soft nature of the gripper means it can deform if it collides with obstacles, and because grasping forces are spread over a larger area the chance of damaging the object being held is reduced. The gripper has the ability to vary its stiffness depending upon how it is to be used, and in this regard two methods of varying the stiffness are explored. In the first method, the finger is formed from an extensor muscle which acts antagonistically against the contractor muscles. Increasing the total pressure in the system increases the stiffness of the fingers. The second approach uses granular jamming to vary the stiffness of the actual finger structure. This thesis explores the behaviour of both extensor and contractor pneumatic muscles and develops a new simplified mathematical model of the actuator’s behaviour. The two methods of stiffness variation are then assessed experimentally. A number of multi-fingered grippers are then designed and their kinematics determined before prototypes are presented. Control of the grippers was then explored, along with the ability to adjust the stiffness of the grasp.
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Homberg, Bianca (Bianca S. ). "Robust proprioceptive grasping with a soft robot hand." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106123.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 85-88).
This work presents a soft hand capable of robustly grasping and identifying objects based on internal state measurements along with a combined system which autonomously performs grasps. A highly compliant soft hand allows for intrinsic robustness to grasping uncertainties; the addition of internal sensing allows the configuration of the hand and object to be detected. The hand can be configured in different ways using finger unit modules. The finger module includes resistive force sensors on the fingertips for contact detection and resistive bend sensors for measuring the curvature profile of the finger. The curvature sensors can be used to estimate the contact geometry and thus to distinguish between a set of grasped objects. With one data point from each finger, the object grasped by the hand can be identified. A clustering algorithm to find the correspondence for each grasped object is presented for both enveloping grasps and pinch grasps. This hand is incorporated into a full system with vision and motion planning on the Baxter robot to autonomously perform grasps of objects placed on a table. This hand is a first step towards proprioceptive soft grasping.
by Bianca Homberg.
M. Eng.
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Kandhari, Akhil. "Control and Analysis of Soft Body Locomotion on a Robotic Platform." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1579793861351961.
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Tzemanaki, A. "Anthropomorphic surgical system for soft tissue robot-assisted surgery." Thesis, University of the West of England, Bristol, 2016. http://eprints.uwe.ac.uk/28870/.
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Over the past century, abdominal surgery has seen a rapid transition from open procedures to less invasive methods such as laparoscopy and robot-assisted minimally invasive surgery (R-A MIS). These procedures have significantly decreased blood loss, postoperative morbidity and length of hospital stay in comparison with open surgery. R-A MIS has offered refined accuracy and more ergonomic instruments for surgeons, further minimising trauma to the patient. This thesis aims to investigate, design and prototype a novel system for R-A MIS that will provide more natural and intuitive manipulation of soft tissues and, at the same time, increase the surgeon's dexterity. The thesis reviews related work on surgical systems and discusses the requirements for designing surgical instrumentation. From the background research conducted in this thesis, it is clear that training surgeons in MIS procedures is becoming increasingly long and arduous. Furthermore, most available systems adopt a design similar to conventional laparoscopic instruments or focus on different techniques with debatable benefits. The system proposed in this thesis not only aims to reduce the training time for surgeons but also to improve the ergonomics of the procedure. In order to achieve this, a survey was conducted among surgeons, regarding their opinions on surgical training, surgical systems, how satisfied they are with them and how easy they are to use. A concept for MIS robotic instrumentation was then developed and a series of focus group meetings with surgeons were run to discuss it. The proposed system, named microAngelo, is an anthropomorphic master-slave system that comprises a three-digit miniature hand that can be controlled using the master, a three-digit sensory exoskeleton. While multi-fingered robotic hands have been developed for decades, none have been used for surgical operations. As the system has a human centred design, its relation to the human hand is discussed. Prototypes of both the master and the slave have been developed and their design and mechanisms is demonstrated. The accuracy and repeatability of the master as well as the accuracy and force capabilities of the slave are tested and discussed.
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Cloitre, Audren Damien Prigent. "Design and control of a soft biomimetic batoid robot." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81598.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 71-74).
This thesis presents the work accomplished in the design, experimental characterization and control of a soft batoid robot. The shape of the robot is based on the body of the common stingray, Dasyatidae, and is made of soft silicone polymers. Although soft batoid robots have been previously studied, the novelty brought by the present work centers around autonomy and scale, making it suitable for field operations. The design of the robot relies on the organismic consideration that the stingray body is rigid at its center and flexible towards its fins. Indeed, all mechanical and electrical parts are inside a rigid shell embedded at the center of the robot's flexible body. The silicone forms a continuum which encases the shell and constitutes the two pectoral fins of the robot. The core idea of this design is to make use of the natural modes of vibration of the soft silicone to recreate the fin kinematics of an actual stingray. By only actuating periodically the front of the fins, a wave propagating downstream the soft fins is created, producing a net forward thrust. Experiments are conducted to quantify the robot's swimming capabilities at different regimes of actuation. The forward velocity, the stall forces produced by the robot when it is flapping its fins while being clamped, and the power consumption of the actuation are all measured. The peak velocity of the robot is 0.35 body-length per second and is obtained for a flapping frequency of 1.4 Hz and a flapping amplitude of 30°. At a flapping frequency of 2 Hz, and an amplitude of 30°, the maximum stall forward force of the robot averages at 45 Newtons and peaks at 150 Newtons. Other data collected is used to better understand the hydrodynamics of the robot.
by Audren Damien Prigent Cloitre.
S.M.
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Kraus, Dustan Paul. "Coordinated, Multi-Arm Manipulation with Soft Robots." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7066.
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Soft lightweight robots provide an inherently safe solution to using robots in unmodeled environments by maintaining safety without increasing cost through expensive sensors. Unfortunately, many practical problems still need to be addressed before soft robots can become useful in real world tasks. Unlike traditional robots, soft robot geometry is not constant but can change with deflation and reinflation. Small errors in a robot's kinematic model can result in large errors in pose estimation of the end effector. This error, coupled with the inherent compliance of soft robots and the difficulty of soft robot joint angle sensing, makes it very challenging to accurately control the end effector of a soft robot in task space. However, this inherent compliance means that soft robots lend themselves nicely to coordinated multi-arm manipulation tasks, as deviations in end effector pose do not result in large force buildup in the arms or in the object being manipulated. Coordinated, multi-arm manipulation with soft robots is the focus of this thesis. We first developed two tools enabling multi-arm manipulation with soft robots: (1) a hybrid servoing control scheme for task space control of soft robot arms, and (2) a general base placement optimization for the robot arms in a multi-arm manipulation task. Using these tools, we then developed and implemented a simple multi-arm control scheme. The hybrid servoing control scheme combines inverse kinematics, joint angle control, and task space servoing in order to reduce end effector pose error. We implemented this control scheme on two soft robots and demonstrated its effectiveness in task space control. Having developed a task space controller for soft robots, we then approached the problem of multi-arm manipulation. The placement of each arm for a multi-arm task is non-trivial. We developed an evolutionary optimization that finds the optimal arm base location for any number of user-defined arms in a user-defined task or workspace. We demonstrated the utility of this optimization in simulation, and then used it to determine the arm base locations for two arms in two real world coordinated multi-arm manipulation tasks. Finally, we developed a simple multi-arm control scheme for soft robots and demonstrated its effectiveness using one soft robot arm, and one rigid robot with low-impedance torque control. We placed each arm base in the pose determined by the base placement optimization, and then used the hybrid servoing controller in our multi-arm control scheme to manipulate an object through two desired trajectories.
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Boxerbaum, Alexander Steele. "Continuous Wave Peristaltic Motion in a Robot." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1333649965.
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Giannaccini, M. E. "Safe and effective physical human-robot interaction : approaches to variable compliance via soft joints and soft grippers." Thesis, University of the West of England, Bristol, 2015. http://eprints.uwe.ac.uk/27224/.
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The work described in this thesis focusses on designing and building two novel physical devices in a robotic arm structure. The arm is intended for human-robot interaction in the domestic assistive robotics area. The first device aims at helping to ensure the safety of the human user. It acts as a mechanical fuse and disconnects the robotic arm link from its motor in case of collision. The device behaves in a rigid manner in normal operational times and in a compliant manner in case of potentially harmful collisions: it relies on a variable compliance. The second device is the end-effector of the robotic arm. It is a novel grasping device that aims at accommodating varying object shapes. This is achieved by the structure of the grasping device that is a soft structure with a compliant and a rigid phase. Its completely soft structure is able to mould to the object's shape in the compliant phase, while the rigid phase allows holding the object in a stable way. In this study, variable compliance is defined as a physical structure's change from a compliant to a rigid behaviour and vice versa. Due to its versatility and effectiveness, variable compliance has become the founding block of the design of the two devices in the robot arm physical structure. The novelty of the employment of variable compliance in this thesis resides in its use in both rigid and soft devices in order to help ensure both safety and adaptable grasping in one integrated physical structure, the robot arm. The safety device has been designed, modelled, produced, tested and physically embedded in the robot arm system. Compared to previous work in this field, the feature described in this thesis' work has a major advantage: its torque threshold can be actively regulated depending on the operational situation. The threshold torque is best described by an exponential curve in the mathematical model while it is best fit by a second order equation in the experimental data. The mismatch is more considerable for high values of threshold torque. However, both curves reflect that threshold torque magnitude increases by increasing the setting of the device. Testing of both the passive decoupling and active threshold torque regulation show that both are successfully obtained. The second novel feature of the robot arm is the soft grasping device inspired by hydrostatic skeletons. Its ability to passively adapts to complex shapes objects, reduces the complexity of the grasping action control. This gripper is low-cost, soft, cable-driven and it features no stiff sections. Its versatility, variable compliance and stable grasp are shown in several experiments. A model of the forward kinematics of the system is derived from observation of its bending behaviour. Variable compliance has shown to be a very relevant principle for the design and implementation of a robotic arm aimed at safely interacting with human users and that can reduce grasp control complexity by passively adapting to the object's shape.
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AMARA, VISHNU DEV. "Energetic and Dynamic Performance Enhancements for Compliant Robot Actuation." Doctoral thesis, Università degli studi di Genova, 2021. http://hdl.handle.net/11567/1045123.
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The vast repertoire of human skills enable nimble and graceful execution of several habitual tasks. On the contrary, despite many advances, robots are still far from matching human capabilities. Robots can be envisioned to take up the oft-touted dull, dirty and dangerous humans jobs only with breakthroughs in their energetic and dynamic characteristics. A typical bio-inspired approach that can potentially help robots achieve the aforesaid performance aspects is joint compliance. Compliant actuation technology has vastly diversified in the last decade. A survey of the various actuator methodologies hints at possible advances for series-clutched and series-parallel multi-articulated actuation. To address them, the thesis builds upon these existing actuation concepts and focuses on specifically improving their energetic and dynamic performance characteristics.
Energetic benefits of series elastic actuation is often marred by gearbox friction. An instance is when friction dissipates the link energy impeding gravity-driven link motions. At such instances, clutches can help stem undesired power-flows by decoupling the link and motor. In addition, when natural link motions are to be damped while not driving the actuator, clutches can be used to actively exploit slippage to dissipate the excess mechanical energy. Such a continuous clutching action has significant implications for energy economy. Therefore, first contributions of this thesis is towards deriving an energy-based model and an optimal controller for a series clutched actuator. In addition, an optimization-based approach is sought to obtain design parameters for a physical implementation of the actuator.
Parallel actuators can often augment series elastic actuators as secondary torque sources. Owing to their energy storage capabilities, they have been used to greatly enhance robot energetics. However, the joint torque resolution problem when employing dissimilar (series and parallel) actuators is difficult, more so when the parallel actuators are biarticulated. Therefore, a second contribution of the thesis is towards deriving an energetic criteria-driven, torque resolution controller. An energetic analysis of the various criteria predicts that allocation of maximum possible torque demand to the higher efficiency actuators may not necessarily be the best strategy at all times. The analysis when extended to a wider range of motion frequencies predicts progressively lesser utilization of parallel actuators can contribute to higher energy-economy.
Through energy-recycling, mono and biarticulated parallel compliance can amplify jumping performance of series elastic actuated robots. While the principle augments robot performance from the mechanical domain, joint velocities powered by series actuators yet suffer from limited voltage. Field weakening is applied at the electrical level to alleviate voltage constraints. In order to maximize energetic economy during such highly dynamic motions, trajectory optimization is further employed with knowledge of actuation capabilities and novel power constraints. Therefore, the confluence of these methods is proposed and experimentally demonstrated to significantly enhance jumping performance. Finally, the efficacy of these concepts towards enhancing explosive motions are quantified through a centroidal dynamic manipulability analysis. These results lead to a third broad contribution from this thesis.
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Iqbal, Muhammad Zubair. "Design of Soft Rigid Devices for Assistive Robotics and Industrial Applications." Doctoral thesis, Università di Siena, 2021. http://hdl.handle.net/11365/1152251.
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Soft robots are getting more and more popular in rehabilitation and industrial scenarios. They
often come into play where the rigid robots fail to perform certain functions. The advantage of
using soft robots lies in the fact that they can easily conform to the obstacles and depict delicacy
in gripping, manipulating, and controlling deformable and fragile objects without causing them
any harm. In rehabilitation scenarios, devices developed on the concept of soft robots are pretty
helpful in changing the lives of those who suffer body impairments due to stroke or any other
accident. These devices provide support in carrying out daily life activities without the need
and support of another person. Also, these devices are beneficial in the training phase where
the patient is going through the rehabilitation phase and has to do multiple exercises of the
upper limb, wrist, or hand. Similarly, the grippers developed on the basic principle of soft
robots are very common in the industries or at least getting common. Their advantages are a lot
as compared to the rigid robotics manipulators. Soft grippers tend to adapt to the shape of the
object without causing any damage to it, providing a stable grasp. It can also help reduce the
complexity in the design and development, for example, underactuated. Underactuated grippers
use the minimum number of actuators to provide the same function that requires more actuators
with a rigid gripper. Also, the soft structure allows to design specific trajectories to complete
a certain grasping and manipulation task. This thesis presents devices for rehabilitation and
assistive application to help people with upper limb impairment, especially wrist and hand
functions. These devices have been designed to provide the people, with limited capabilities of
hand and wrist functions, to live their lives with ease without being dependent on any other
family member. Similarly, I present different soft grippers and a soft environment that provides
different advantages and can do various grasp and manipulation tasks. I have presented results
for each device, rehabilitation and assistive devices are used by a patient suffering from stroke
and having limited movement of wrist and hand function. At the same time, the grippers
are supported with a set of experiments that provide deep insight into the advantages of each
gripper in industrial applications.
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Zhang, Zhongkai. "Vision-based calibration, position control and force sensing for soft robots." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I001/document.
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La modélisation de robots souples est extrêmement difficile, à cause notamment du nombre théoriquement infini des degrés de liberté. Cette difficulté est accentuée lorsque les robots ont des configurations complexes. Ce problème de modélisation entraîne de nouveaux défis pour la calibration et la conception des commandes des robots, mais également de nouvelles opportunités avec de nouvelles stratégies de détection de force possibles. Cette thèse a pour objectif de proposer des solutions nouvelles et générales utilisant la modélisation et la vision. La thèse présente dans un premier temps un modèle cinématique à temps discret pour les robots souples reposant sur la méthode des éléments finis (FEM) en temps réel. Ensuite, une méthode de calibration basée sur la vision du système de capteur-robot et des actionneurs est étudiée. Deux contrôleurs de position en boucle fermée sont conçus. En outre, pour traiter le problème de la perte d'image, une stratégie de commande commutable est proposée en combinant à la fois le contrôleur à boucle ouverte et le contrôleur à boucle fermée. Deux méthodes (avec et sans marqueur(s)) de détection de force externe pour les robots déformables sont proposées. L'approche est basée sur la fusion de mesures basées sur la vision et le modèle par FEM. En utilisant les deux méthodes, il est possible d'estimer non seulement les intensités, mais également l'emplacement des forces externes. Enfin, nous proposons une application concrète : un robot cathéter dont la flexion à l'extrémité est piloté par des câbles. Le robot est contrôlé par une stratégie de contrôle découplée qui permet de contrôler l’insertion et la flexion indépendamment, tout en se basant sur un modèle FEMThe modeling of soft robots which have, theoretically, infinite degrees of freedom, are extremely difficult especially when the robots have complex configurations. This difficulty of modeling leads to new challenges for the calibration and the control design of the robots, but also new opportunities with possible new force sensing strategies. This dissertation aims to provide new and general solutions using modeling and vision. The thesis at first presents a discrete-time kinematic model for soft robots based on the real-time Finite Element (FE) method. Then, a vision-based simultaneous calibration of sensor-robot system and actuators is investigated. Two closed-loop position controllers are designed. Besides, to deal with the problem of image feature loss, a switched control strategy is proposed by combining both the open-loop controller and the closed-loop controller. Using soft robot itself as a force sensor is available due to the deformable feature of soft structures. Two methods (marker-based and marker-free) of external force sensing for soft robots are proposed based on the fusion of vision-based measurements and FE model. Using both methods, not only the intensities but also the locations of the external forces can be estimated.As a specific application, a cable-driven continuum catheter robot through contacts is modeled based on FE method. Then, the robot is controlled by a decoupled control strategy which allows to control insertion and bending independently. Both the control inputs and the contact forces along the entire catheter can be computed by solving a quadratic programming (QP) problem with a linear complementarity constraint (QPCC)
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MerchaÌn-Cruz, Emmanuel Alejandro. "Soft-computing techniques in the trajectory planning of robot manipulators sharing a common workspace." Thesis, University of Sheffield, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419281.
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Andersen, Kayla B. Andersen. "A Nitinol Actuated Worm-Inspired Robot Capable of Forward Motion, Turning, and Climbing Obstacles." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1497021593146329.
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Terry, Jonathan Spencer. "Adaptive Control for Inflatable Soft Robotic Manipulators with Unknown Payloads." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6769.
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Soft robotic platforms are becoming increasingly popular as they are generally safer, lighter, and easier to manufacture than their more rigid, heavy, traditional counterparts. These soft platforms, while inherently safer, come with significant drawbacks. Their compliant components are more difficult to model, and their underdamped nature makes them difficult to control. Additionally, they are so lightweight that a payload of just a few pounds has a significant impact on the manipulator dynamics. This thesis presents novel methods for addressing these issues. In previous research, Model Predictive Control has been demonstrably useful for joint angle control for these soft robots, using a rigid inverted pendulum model for each link. A model describing the dynamics of the entire arm would be more desirable, but with high Degrees of Freedom it is computationally expensive to optimize over such a complex model. This thesis presents a method for simplifying and linearizing the full-arm model (the Coupling-Torque method), and compares control performance when using this method of linearization against control performance for other linearization methods. The comparison shows the Coupling-Torque method yields good control performance for manipulators with seven or more Degrees of Freedom. The decoupled nature of the Coupling-Torque method also makes adaptive control, of the form described in this thesis, easier to implement. The Coupling-Torque method improves performance when the dynamics are known, but when a payload of unknown mass is attached to the end effector it has a significant impact on the dynamics. Adaptive Control is needed at this point to compensate for the model's poor approximation of the system. This thesis presents a method of layering Model Reference Adaptive Control in concert with Model Predictive Control that improves control performance in this scenario. The adaptive controller modifies dynamic parameters, which are then delivered to the optimizer, which then returns inputs for the system that take all of this information into account. This method has been shown to reduce step input tracking error by 50% when implemented on the soft robot.
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Sherrod, Vallan Gray. "Design Optimization for a Compliant,Continuum-Joint, Quadruped Robot." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7766.
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Legged robots have the potential to cover terrain not accessible to wheel-based robots and vehicles. This makes them better suited to perform tasks, such as search and rescue, in real-world unstructured environments. Pneumatically-actuated, compliant robots are also more suited than their rigid counterparts to work in real-world unstructured environments with humans where unintentional contact may occur. This thesis seeks to combine the benefits of these two type of robots by implementing design methods to aid in the design choice of a 16 degree of freedom (DoF) compliant, continuum-joint quadruped. This work focuses on the design optimization, especially the definition of design metrics, for this type of robot. The work also includes the construction and closed-loop control of a four-DoF continuum-joint leg used to validate design methods.We define design metrics for legged robot metrics that evaluate their ability to traverse unstructured terrain, carry payloads, find stable footholds, and move in desired directions. These design metrics require a sampling of a legged-robot's complete configuration space. For high-DoF robots, such as the 16-DoF in evaluated in this work, the evaluation of these metrics become intractable with contemporary computing power. Therefore, we present methods that can be used to simplify and approximate these metrics. These approximations have been validated on a simulated four-DoF legged robot where they can tractably be compared against their full counterparts.Using the approximations of the defined metrics, we have performed a multi-objective design optimization to investigate the ten-dimensional design space of a 16-DoF compliant, continuum-joint quadruped. The design variables used include leg link geometry, robot base dimensions, and the leg mount angles. We have used an evolutionary algorithm as our optimization method which converged on a Pareto front of optimal designs. From these set of designs, we are able to identify the trade-offs and design differences between robots that perform well in each of the different design metrics. Because of our approximation of the metrics, we were able to perform this optimization on a supercomputer with 28 cores in less than 40 hours.We have constructed a 1.3 m long continuum-joint leg from one of the resulting quadruped designs of the optimization. We have implemented configuration estimation and control and force control on this leg to evaluate the leg payload capability. Using these controllers, we have conducted an experiment to compare the leg's ability to provide downward force in comparison with its theoretical payload capabilities. We then demonstrated how the torque model used in the calculation of payload capabilities can accurately calculate trends in force output from the leg.
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Mehringer, Anna G. "FabricWorm: A Biologically-Inspired Robot That Demonstrates Structural Advantages of a Soft Exterior for Peristaltic Locomotion." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1493900162956628.
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Saleeby, Kyle Scott. "Design of soft-body robot with wireless communication for leak detection in large diameter pipe systems." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112547.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references.
Water leaks pose a major problem of efficiency and cost to municipalities and industries that cover significant area. While current commercial methods to address these problems do not provide convenient or low cost methods to detect leaks, a soft-body pipe leak detection robot has been developed to traverse small, 50mm diameter water pipe systems. This robot has proven to be effective in small diameter pipes, but its scalability for large diameter pipes is unknown. The focus of this thesis is to scale up the leak detection robot for 300mm diameter pipes and fabricate a robot prototype. In particular, the relationship between the shape of the robot and its maneuverability was explored, such that it was designed to passively travel through the pipe, driven by water flow. The robot was designed to successfully pass through changes in pipe diameter, pipe bends, and through partially clogged regions. To detect and distinguish pipe leaks from other debris in the pipe, two sensors were integrated in the robot. Experimental testing was conducted with the robot to verify functionality of its leak detection sensors. Supporting electronics were also implemented to wirelessly charge and communicate with the robot.
by Kyle Scott Saleeby.
S.B.
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Hyatt, Phillip Edmond. "Robust Real-Time Model Predictive Control for High Degree of Freedom Soft Robots." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8453.
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This dissertation is focused on the modeling and robust model-based control of high degree-of-freedom (DoF) systems. While most of the contributions are applicable to any difficult-to-model system, this dissertation focuses specifically on applications to large-scale soft robots because their many joints and pressures constitute a high-DoF system and their inherit softness makes them difficult to model accurately. First a joint-angle estimation and kinematic calibration method for soft robots is developed which is shown to decrease the pose prediction error at the end of a 1.5 m robot arm by about 85\%. A novel dynamic modelling approach which can be evaluated within microseconds is then formulated for continuum type soft robots. We show that deep neural networks (DNNs) can be used to approximate soft robot dynamics given training examples from physics-based models like the ones described above. We demonstrate how these machine-learning-based models can be evaluated quickly to perform a form of optimal control called model predictive control (MPC). We describe a method of control trajectory parameterization that enables MPC to be applied to systems with more DoF and with longer prediction horizons than previously possible. We show that this parameterization decreases MPC's sensitivity to model error and drastically reduces MPC solve times. A novel form of MPC is developed based on an evolutionary optimization algorithm that allows the optimization to be parallelized on a computer's graphics processing unit (GPU). We show that this evolutionary MPC (EMPC) can greatly decrease MPC solve times for high DoF systems without large performance losses, especially given a large GPU. We combine the ideas of machine learned DNN models of robot dynamics, with parameterized and parallelized MPC to obtain a nonlinear version of EMPC which can be run at higher rates and find better solutions than many state-of-the-art optimal control methods. Finally we demonstrate an adaptive form of MPC that can compensate for model error or changes in the system to be controlled. This adaptive form of MPC is shown to inherit MPC's robustness to completely unmodeled disturbances and adaptive control's ability to decrease trajectory tracking errors over time.
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Li, Min. "Haptic feedback of rigid tool/soft object interaction in medical training and robot-assisted minimally invasive surgery." Thesis, King's College London (University of London), 2014. https://kclpure.kcl.ac.uk/portal/en/theses/haptic-feedback-of-rigid-tool--soft-object-interaction-in-medical-training-and-robotassisted-minimally-invasive-surgery(ec321790-1b95-4ae6-a913-abd10a6a1f13).html.
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Sense of touch is crucial for surgeons to effectively identify tumours and boundaries, and, thus to achieve successful cancer resections. To overcome the touch information loss which occurs during robotic-assisted surgical procedures, researchers have proposed methods capable of acquiring partial haptic feedback and mimicking the physical interaction which takes place between surgical tools and human tissue during palpation. This thesis proposes and evaluates haptic palpation systems and suggests the combination of different feedback methods for tumour identification in medical training and robot-assisted minimally invasive surgery using tissue models based on rolling indentation. A real-time visual tissue stiffness feedback method is proposed and compared to the performance of direct force feedback using tumour identification performance based on user studies with human subjects. The trade-off problem between system transparency and stability, which is caused by direct force feedback using a tele-manipulation system, is circumvented with the introduction of an intra-operative haptic tissue model generation method capable of representing tissue stiffness distribution of the examined soft tissue. During palpation, force feedback is exerted based on this model. This thesis proposes pseudo-haptic feedback and visualization of tissue surface deformation as an effective method to provide realistic palpation experience, which does not require the use of expensive haptic devices and is capable of handling three-dimensional haptic information. The tumour identification results are compared using different input devices: a computer mouse, a 3-DOF motion tracking input device and force-sensitive 2D haptic surface input devices. Furthermore, it is shown that the performance of haptic systems can be improved beyond the performance of force-feedback-only haptic systems by intelligently combining force feedback and pseudo-haptic feedback. Multi-fingered palpation is more effective in detecting differences in stiffness in the examined tissue than single-fingered palpation methods. Two approaches of multi-fingered palpation are proposed, studied and evaluated in this thesis: (1) methods using pseudo-haptic feedback and (2) those that use stiffness actuators. The performance of these methods is compared with the performance of single-fingered palpation approaches.
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Runge-Borchert, Gundula [Verfasser]. "A Holistic Framework for the Design, Modeling, and Control of Soft Pneumatic Robot Systems / Gundula Runge-Borchert." Garbsen : TEWISS - Technik und Wissen GmbH, 2019. http://d-nb.info/1204218145/34.
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Gillespie, Morgan Thomas. "Comparing Efficacy of Different Dynamic Models for Control of Underdamped, Antagonistic, Pneumatically Actuated Soft Robots." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5996.
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Research in soft robot hardware has led to the development of platforms that allow for safer performance when working in uncertain or dynamic environments. The potential of these platforms is limited by the lack of proper dynamic models to describe or controllers to operate them. A common difficulty associated with these soft robots is a representation for torque, the common electromechanical relation seen in motors does not apply. In this thesis, several different torque models are presented and used to construct linear state-space models. The control limitations on soft robots are induced by natural compliance inherent to the hardware. This inherent compliance results in soft robots that are commonly underdamped and present significant oscillations when accelerated quickly. These oscillations can be mitigated through model-based controllers which can anticipate these oscillations. In this thesis, multiple model predictive controllers are implemented with the torque models produced and results are presented for an inflatable single-DoF pneumatically actuated soft robot. Larger, multi-DoF, soft robots present additional issues with control, where flexibility in one joint impacts control in others. In this thesis a preliminary method and results for controlling multiple joints on an inflatable multi-DoF pneumatically actuated soft robot are presented. While model predictive controllers are capable, their control commands are defined by solving an optimization constrained by model dynamics. This optimization relies on minimizing the cost of a user-defined objective function. This objective function contains a series of weights, which allow the user to tune the importance of each component in the objective function. As there are no calculations that can be performed to tune model predictive controllers to achieve superior control performance, they often need to be tuned tediously by a skilled operator. In this thesis, a method for automated discrete performance identification and model predictive controller weight tuning is presented. This thesis constructs multiple state-space models for single- and multi-DoF underdamped, antagonistic, pneumatically actuated soft robots and shows that these models can be used with model predictive control, tuned for performance, to achieve accurate joint position control.
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Alvarez-Palacio, Juan Miguel. "Contrôle commande d'un robot ultra léger gonflable à actionneurs pneumatiques textiles." Thesis, Paris, HESAM, 2020. http://www.theses.fr/2020HESAE007.
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Ce travail de thèse concerne la modélisation et commande d’un bras ultra léger gonflable, actionné par des vérins pneumatiques textiles. Depuis quelques années, le Commissariat à l’Énergie Atomique et aux Énergies Renouvelables (CEA), en partenariat avec l’entreprise Warein SAS, développent un concept innovant de bras robotisé gonflable pour l’inspection en milieu contraint, dont tous les composants de la structure, y compris les actionneurs, sont fait en tissu. La contrainte de légèreté impose des nouveaux défis qui ont des conséquences sur le contrôle commande : les actionneurs utilisés n’ont jamais été étudiés ni caractérisés, les capteurs articulaires utilisés traditionnellement en robotique ne sont pas adaptés à ce type de structure, les capteurs de pression sont éloignés des actionneurs, et le caractère non linéaire des circuits pneumatiques ainsi que les flexibilités de la structure complexifient la commande de la position de l’organe terminale du robot. La première contribution de cette thèse est liée à la modélisation et la caractérisation des actionneurs utilisés, en confrontant une approche analytique et numérique basée sur des simulations par éléments finis, avec des résultats expérimentaux. La deuxième contribution concerne la proposition d’un capteur articulaire, basée sur l’utilisation d’un réseau de centrales inertielles placées sur chaque segment du bras. Dans ce cadre, une méthode d’estimation d’orientation relative entre deux repères a été proposée en utilisant le formalisme des quaternions. Finalement, la commande d’une des articulations du robot est réalisée avec l’implémentation d’une commande par modes glissants. Ces résultats ouvrent des nouvelles perspectives dans l’instrumentation et le contrôle de robots intrinsèquement sûrs, qui pourront avoir un grand impact non seulement dans la robotique d’inspection mais aussi dans l’interaction avec l’humainThis thesis work concerns the modeling and control of an ultra-light inflatable arm, powered by pneumatictextile cylinders. In recent years, the French Atomic Energy and Renewable Energy Commission (CEA), inpartnership with Warein SAS, has been developing an innovative concept of inflatable robotic arms forinspection in a restricted environment, with all the components of the structure, including the actuators, madeof fabric. The constraint of lightness imposes new challenges that have consequences on the control strategy:the actuators have never been studied nor characterized, the joint sensors traditionally used in robotics are notadapted to this type of structure, the pressure sensors are far from the actuators, and the non-linear nature ofthe pneumatic circuits, as well as the flexibility of the structure, make it more complex to control the positionof the robot's end-effector. The first contribution of this thesis is related to the modeling and characterizationof the actuators, by comparing an analytical model and numerical approach based on finite elementssimulations with experimental results. The second contribution concerns the proposal of a joint sensor, basedon the use of a network of Inertial Measurement Units (IMU) placed on each segment of the arm. In thiscontext, a method for estimating the relative orientation between two bodies was proposed using the quaternionformalism. Finally, the control of one of the robot joints is carried out with the implementation of a slidingmode control. These results open new perspectives in the instrumentation and control of intrinsically saferobots, which will have a significant impact not only on inspection robotics but also on close interaction withhumans
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Best, Charles Mansel. "Position and Stiffness Control of Inflatable Robotic Links Using Rotary Pneumatic Actuation." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5971.
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Inflatable robots with pneumatic actuation are naturally lightweight and compliant. Both of these characteristics make a robot of this type better suited for human environments where unintentional impacts will occur. The dynamics of an inflatable robot are complex and dynamic models that explicitly allow variable stiffness control have not been well developed. In this thesis, a dynamic model was developed for an antagonistic, pneumatically actuated joint with inflatable links.The antagonistic nature of the joint allows for the control of two states, primarily joint position and stiffness. First a model was developed to describe the position states. The model was used with model predictive control (MPC) and linear quadratic control (LQR) to control a single degree of freedom platform to within 3° of a desired angle. Control was extended to multiple degrees of freedom for a pick and place task where the pick was successful ten out of ten times and the place was successful eight out of ten times.Based on a torque model for the joint which accounts for pressure states that was developed in collaboration with other members of the Robotics and Dynamics Lab at Brigham Young University, the model was extended to account for the joint stiffness. The model accounting for position, stiffness, and pressure states was fit to data collected from the actual joint and stiffness estimation was validated by stiffness measurements.Using the stiffness model, sliding mode control (SMC) and MPC methods were used to control both stiffness and position simultaneously. Using SMC, the joint stiffness was controlled to within 3 Nm/rad of a desired trajectory at steady state and the position was controlled to within 2° of a desired position trajectory at steady state. Using MPC,the joint stiffness was controlled to within 1 Nm/rad of a desired trajectory at steady state and the position was controlled to within 2° of a desired position trajectory at steady state. Stiffness control was extended to multiple degrees of freedom using MPC where each joint was treated as independent and uncoupled. Controlling stiffness reduced the end effecter deflection by 50% from an applied load when high stiffness (50 Nm/rad) was used rather than low stiffness (35 Nm/rad).This thesis gives a state space dynamic model for an inflatable, pneumatically actuated joint and shows that the model can be used for accurate and repeatable position and stiffness control with stiffness having a significant effect.
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Day, Nathan McClain. "Tactile Sensing and Position Estimation Methods for Increased Proprioception of Soft-Robotic Platforms." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7004.
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Soft robots have the potential to transform the way robots interact with their environment. This is due to their low inertia and inherent ability to more safely interact with the world without damaging themselves or the people around them. However, existing sensing for soft robots has at least partially limited their ability to control interactions with their environment. Tactile sensors could enable soft robots to sense interaction, but most tactile sensors are made from rigid substrates and are not well suited to applications for soft robots that can deform. In addition, the benefit of being able to cheaply manufacture soft robots may be lost if the tactile sensors that cover them are expensive and their resolution does not scale well for manufacturability. Soft robots not only need to know their interaction forces due to contact with their environment, they also need to know where they are in Cartesian space. Because soft robots lack a rigid structure, traditional methods of joint estimation found in rigid robots cannot be employed on soft robotic platforms. This requires a different approach to soft robot pose estimation. This thesis will discuss both tactile force sensing and pose estimation methods for soft-robots. A method to make affordable, high-resolution, tactile sensor arrays (manufactured in rows and columns) that can be used for sensorizing soft robots and other soft bodies isReserved developed. However, the construction results in a sensor array that exhibits significant amounts of cross-talk when two taxels in the same row are compressed. Using the same fabric-based tactile sensor array construction design, two different methods for cross-talk compensation are presented. The first uses a mathematical model to calculate a change in resistance of each taxel directly. The second method introduces additional simple circuit components that enable us to isolate each taxel electrically and relate voltage to force directly. This thesis also discusses various approaches in soft robot pose estimation along with a method for characterizing sensors using machine learning. Particular emphasis is placed on the effectiveness of parameter-based learning versus parameter-free learning, in order to determine which method of machine learning is more appropriate and accurate for soft robot pose estimation. Various machine learning architectures, such as recursive neural networks and convolutional neural networks, are also tested to demonstrate the most effective architecture to use for characterizing soft-robot sensors.
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Munawar, Adnan. "An Asynchronous Simulation Framework for Multi-User Interactive Collaboration: Application to Robot-Assisted Surgery." Digital WPI, 2019. https://digitalcommons.wpi.edu/etd-dissertations/566.
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The field of surgery is continually evolving as there is always room for improvement in the post-operative health of the patient as well as the comfort of the Operating Room (OR) team. While the success of surgery is contingent upon the skills of the surgeon and the OR team, the use of specialized robots has shown to improve surgery-related outcomes in some cases. These outcomes are currently measured using a wide variety of metrics that include patient pain and recovery, surgeon’s comfort, duration of the operation and the cost of the procedure. There is a need for additional research to better understand the optimal criteria for benchmarking surgical performance. Presently, surgeons are trained to perform robot-assisted surgeries using interactive simulators. However, in the absence of well-defined performance standards, these simulators focus primarily on the simulation of the operative scene and not the complexities associated with multiple inputs to a real-world surgical procedure. Because interactive simulators are typically designed for specific robots that perform a small number of tasks controlled by a single user, they are inflexible in terms of their portability to different robots and the inclusion of multiple operators (e.g., nurses, medical assistants). Additionally, while most simulators provide high-quality visuals, simplification techniques are often employed to avoid stability issues for physics computation, contact dynamics and multi-manual interaction. This study addresses the limitations of existing simulators by outlining various specifications required to develop techniques that mimic real-world interactions and collaboration. Moreover, this study focuses on the inclusion of distributed control, shared task allocation and assistive feedback -- through machine learning, secondary and tertiary operators -- alongside the primary human operator.
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Barthelmes, Stefan [Verfasser]. "Model-Based Chassis Control of a Wheeled Mobile Robot on Soft Ground Using the Example of the ExoMars Planetary Exploration Rover / Stefan Barthelmes." München : Verlag Dr. Hut, 2020. http://d-nb.info/1222353156/34.
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Velor, Tosan. "A Low-Cost Social Companion Robot for Children with Autism Spectrum Disorder." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41428.
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Robot assisted therapy is becoming increasingly popular. Research has proven it can be of benefit to persons dealing with a variety of disorders, such as Autism Spectrum Disorder (ASD), Attention Deficit Hyperactivity Disorder (ADHD), and it can also provide a source of emotional support e.g. to persons living in seniors’ residences. The advancement in technology and a decrease in cost of products related to consumer electronics, computing and communication has enabled the development of more advanced social robots at a lower cost. This brings us closer to developing such tools at a price that makes them affordable to lower income individuals and families. Currently, in several cases, intensive treatment for patients with certain disorders (to the level of becoming effective) is practically not possible through the public health system due to resource limitations and a large existing backlog. Pursuing treatment through the private sector is expensive and unattainable for those with a lower income, placing them at a disadvantage. Design and effective integration of technology, such as using social robots in treatment, reduces the cost considerably, potentially making it financially accessible to lower income individuals and families in need. The Objective of the research reported in this manuscript is to design and implement a social robot that meets the low-cost criteria, while also containing the required functions to support children with ASD. The design considered contains knowledge acquired in the past through research involving the use of various types of technology for the treatment of mental and/or emotional disabilities.
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Moffat, Shannon Marija. "Biologically Inspired Legs and Novel Flow Control Valve Toward a New Approach for Accessible Wearable Robotics." Digital WPI, 2019. https://digitalcommons.wpi.edu/etd-theses/1279.
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The Humanoid Walking Robot (HWR) is a research platform for the study of legged and wearable robots actuated with Hydro Muscles. The fluid operated HWR is representative of a class of biologically inspired, and in some aspects highly biomimetic robotic musculoskeletal appendages showing certain advantages in comparison to more conventional artificial limbs and braces for physical therapy/rehabilitation, assistance of daily living, and augmentation. The HWR closely mimics the human body structure and function, including the skeleton, ligaments, tendons, and muscles. The HWR can emulate close to human-like movements even when subjected to simplified control laws. One of the main drawbacks of this approach is the inaccessibility of an appropriate fluid flow management support system, in the form of affordable, lightweight, compact, and good quality valves suitable for robotics applications. To resolve this shortcoming, the Compact Robotic Flow Control Valve (CRFC Valve) is introduced and successfully proof-of-concept tested. The HWR added with the CRFC Valve has potential to be a highly energy efficient, lightweight, controllable, affordable, and customizable solution that can resolve single muscle action.
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Varier, Vignesh Manoj. "Towards Automated Suturing of Soft Tissue: Automating Suturing Hand-off Task for da Vinci Research Kit Arm using Reinforcement Learning." Digital WPI, 2020. https://digitalcommons.wpi.edu/etd-theses/1369.
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Successful applications of Reinforcement Learning (RL) in the robotics field has proliferated after DeepMind and OpenAI showed the ability of RL techniques to develop intelligent robotic systems that could learn to perform complex tasks. Ever since the use of robots for surgical procedures, researchers have been trying to bring some sort of autonomy into the operating room. Surgical robotic systems such as da Vinci currently provide the surgeons with direct control. To relieve the stress and the burden on the surgeon using the da Vinci robot, semi-automating or automating surgical tasks such as suturing can be beneficial. This work presents a RL-based approach to automate the needle hand-off task. It puts forward two approaches based on the type of environment, a discrete and continuous space approach. For capturing a unique suturing style, user data was collected using the da Vinci Research Kit to generate a sparse reward function. It was used to derive an optimal policy using Q-learning for a discretized environment. Further, a RL framework for da Vinci Research Kit was developed using a real-time dynamics simulator - Asynchronous Multi-Body Framework (AMBF). A model was trained and evaluated to reach the desired goal using model-free RL techniques while considering the dynamics of the robot to help mitigate the difficulty in transferring trained model to real-world robots. Therefore, the developed RL framework would enable the RL community to train surgical robots using state of the art RL techniques and transfer it to real-world robots with minimal effort. Based on the results obtained, the viability of applying RL techniques to develop a supervised level of autonomy for performing surgical tasks is discussed. To summarize, this work mainly focuses on using RL to automate the suture hand-off task in order to move a step towards solving the greater problem of automating suturing.
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Chikhaoui, Mohamed Taha. "Nouveaux concepts de robots à tubes concentriques à micro-actionneurs à base de polymères électro-actifs." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2035/document.
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L’utilisation de systèmes robotiques pour la navigation dans des zones confinées pose des défis intéressants sur les thèmes de conception, de modélisation et de commande, particulièrement complexes pour les applications médicales. Dans ce contexte, nous introduisons un nouveau concept de robots continus, fortement prometteurs pour des applications biomédicales, dont la forme complexe, la dextérité et la capacité de miniaturisation constituent des avantages majeurs pour la navigation intra corporelle. Parmi cette classe, les robots à tubes concentriques (RTC), qui constituent notre point de départ, sont améliorés grâce à un actionnement embarqué innovant. Nos travaux s’articulent autour de deux thématiques aux frontières de l’état de l’art. D’une part, nous avons proposé une modélisation générique et conduit une analyse cinématique approfondie de robots continus basés sur l’architecture des RTC standards et ceux avec changement de courbure de leurs tubes dans deux variantes : courbures unidirectionnelle et bidirectionnelle. D’autre part, leur commande cartésienne en pose complète est introduite avec une validation expérimentale sur un prototype développé de RTC standard, ainsi que les simulations numériques d’une loi de commande comprenant la gestion de la redondance des RTC à changement de courbure. D’autre part, nous avons effectué la synthèse, la caractérisation et la mise en œuvre de micro-actionneurs souples basés sur les polymères électro-actifs (PEA), intégrés pour la première fois dans un robot continu.Ainsi, l’asservissement visuel d’un prototype de robot télescopique souple est proposé avec des précisions atteignant 0.21 mm sur différentes trajectoiresMajor challenges need to be risen in order to perform navigation in confined spaces with robotic systems in terms of design, modeling, and control, particularly for biomedical applications. Indeed,the complex shape, dexterity, and miniaturization ability of continuum robots can help solving intracorporeal navigation problems. Within this class, we introduce a novel concept in order to augment the concentric tube robots (CTR) with embedded actuation. Our works hinge on two majorcutting-edge thematics. On the one hand, we address modeling and kinematics analysis of standard CTR as well as variable curvature CTR with their two varieties : single and double bending directions.Furthermore, we perform the experimental validation of Cartesian control of a CTR prototype, anda task hierarchy based control law for redundancy resolution of CTR with variable curvatures. Onthe other hand, we develop the synthesis, the characterization, and the integration of soft microactuatorsbased on electro-active polymers (EAP) for the first time in a continuum robot. Thus, thevisual servoing of a telescopic soft robot is performed with precisions down to 0.21 mm following different trajectories
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Mosser, Loïc. "Contribution à la conception et la fabrication de robots souples pneumatiques." Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAD009.
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Ce travail de thèse porte sur la conception de robots souples pneumatiques, pour lesquels la mise en mouvement par déformation est produite via des chambres pneumatiques. Nous contribuons à l'obtention d'un robot depuis la formulation du besoin jusqu'à la fabrication du robot. Ainsi, nous abordons les problématiques associées à la conception et la fabrication de ces robots. Pour la conception, nous proposons un algorithme génétique dont le fonctionnement est accéléré par l'usage d'un modèle d'IA permettant l'estimation rapide des comportements de nouvelles géométries et la recherche de solution. Pour la fabrication, nous proposons une plateforme instrumentée de fabrication additive de silicone permettant l'acquisition de nuages de points sur la couche produite. Des indicateurs sont alors proposés pour suivre la production en cours et l'intégrité de robots souples, et ces indicateurs sont évalués expérimentalementThis thesis covers the design of pneumatic soft robots, which move thanks to deformation using pneumatic chambers. We contribute to the design of a robot from the formulation of the need to the manufacturing of the robot. We address the problems associated with the design and manufacture of these robots. For design, we propose a genetic algorithm accelerated by the use of an AI model enabling rapid estimation of the behavior of new geometries and the search for solutions. For manufacturing, we propose an instrumented silicone additive manufacturing platform enabling the acquisition of point clouds on each produced layer. Indicators are then proposed to monitor ongoing production and the integrity of soft robots, and these indicators are evaluated experimentally
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Henke, E. F. Markus, Katherine E. Wilson, and Iain A. Anderson. "Entirely soft dielectric elastomer robots." SPIE, 2017. https://tud.qucosa.de/id/qucosa%3A35126.
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Multifunctional Dielectric Elastomer (DE) devices are well established as actuators, sensors and energy harvesters. Since the invention of the Dielectric Elastomer Switch (DES), a piezoresistive electrode that can directly switch charge on and off, it has become possible to expand the wide functionality of DE structures even more. We show the application of fully soft DE subcomponents in biomimetic robotic structures.
It is now possible to couple arrays of actuator/switch units together so that they switch charge between themselves on and off. One can then build DE devices that operate as self-controlled oscillators. With an oscillator one can produce a periodic signal that controls a soft DE robot { a DE device with its own DE nervous system. DESs were fabricated using a special electrode mixture, and imprinting technology at an exact pre-strain. We have demonstrated six orders of magnitude change in conductivity within the DES over 50% strain. The control signal can either be a mechanical deformation from another DE or an electrical input to a connected dielectric elastomer actuator (DEA). We have demonstrated a variety of fully soft multifunctional subcomponents that enable the design of autonomous soft robots without conventional electronics. The combination of digital logic structures for basic signal processing, data storage in dielectric elastomer ip-ops and digital and analogue clocks with adjustable frequencies, made of dielectric elastomer oscillators (DEOs), enables fully soft, self-controlled and electronics-free robotic structures.
DE robotic structures to date include stiff frames to maintain necessary pre-strains enabling sufficient actuation of DEAs. Here we present a design and production technology for a first robotic structure consisting only of soft silicones and carbon black.
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Pajon, Adrien. "Humanoid robots walking with soft soles." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS060/document.
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Lorsque des changements inattendus de la surface du sol se produisent lors de la marche, le système nerveux central humain doit appliquer des mesures de contrôle appropriées pour assurer une stabilité dynamique. De nombreuses études dans le domaine de la commande moteur ont étudié les mécanismes d'un tel contrôle postural et ont largement décrit comment les trajectoires du centre de masse (COM), le placement des pas et l'activité musculaire s'adaptent pour éviter une perte d'équilibre. Les mesures que nous avons effectuées montrent qu'en arrivant sur un sol mou, les participants ont modulé de façon active les forces de réaction au sol (GRF) sous le pied de support afin d'exploiter les propriétés élastiques et déformables de la surface pour amortir l'impact et probablement dissiper l'énergie mécanique accumulée pendant la ‘chute’ sur la nouvelle surface déformable. Afin de contrôler plus efficacement l'interaction pieds-sol des robots humanoïdes pendant la marche, nous proposons d'ajouter des semelles extérieures souples (c'est-à-dire déformables) aux pieds. Elles absorbent les impacts et limitent les effets des irrégularités du sol pendant le mouvement sur des terrains accidentés. Cependant, ils introduisent des degrés de liberté passifs (déformations sous les pieds) qui complexifient les tâches d'estimation de l'état du robot et ainsi que sa stabilisation globale. Pour résoudre ce problème, nous avons conçu un nouveau générateur de modèle de marche (WPG) basé sur une minimisation de la consommation d'énergie qui génère les paramètres nécessaires pour utiliser conjointement un estimateur de déformation basé sur un modèle éléments finis (FEM) de la semelle souple pour prendre en compte sa déformation lors du mouvement. Un tel modèle FEM est coûteux en temps de calcul et empêche la réactivité en ligne. Par conséquent, nous avons développé une boucle de contrôle qui stabilise les robots humanoïdes lors de la marche avec des semelles souples sur terrain plat et irrégulier. Notre contrôleur en boucle fermée minimise les erreurs sur le centre de masse (COM) et le point de moment nul (ZMP) avec un contrôle en admittance des pieds basé sur un estimateur de déformation simplifié. Nous démontrons son efficacité expérimentalement en faisant marcher le robot humanoïde HRP-4 sur des graviersWhen unexpected changes of the ground surface occur while walking, the human central nervous system needs to apply appropriate control actions to assure dynamic stability. Many studies in the motor control field have investigated the mechanisms of such a postural control and have widely described how center of mass (COM) trajectories, step patterns and muscle activity adapt to avoid loss of balance. Measurements we conducted show that when stepping over a soft ground, participants actively modulated the ground reaction forces (GRF) under the supporting foot in order to exploit the elastic and compliant properties of the surface to dampen the impact and to likely dissipate the mechanical energy accumulated during the ‘fall’ onto the new compliant surface.In order to control more efficiently the feet-ground interaction of humanoid robots during walking, we propose adding outer soft (i.e. compliant) soles to the feet. They absorb impacts and cast ground unevenness during locomotion on rough terrains. However, they introduce passive degrees of freedom (deformations under the feet) that complexify the tasks of state estimation and overall robot stabilization. To address this problem, we devised a new walking pattern generator (WPG) based on a minimization of the energy consumption that offers the necessary parameters to be used jointly with a sole deformation estimator based on finite element model (FEM) of the soft sole to take into account the sole deformation during the motion. Such FEM computation is time costly and inhibit online reactivity. Hence, we developed a control loop that stabilizes humanoid robots when walking with soft soles on flat and uneven terrain. Our closed-loop controller minimizes the errors on the center of mass (COM) and the zero-moment point (ZMP) with an admittance control of the feet based on a simple deformation estimator. We demonstrate its effectiveness in real experiments on the HRP-4 humanoid walking on gravels
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Horchler, Andrew de Salle. "Design of Stochastic Neural-inspired Dynamical Architectures: Coordination and Control of Hyper-redundant Robots." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459442036.
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Henke, E. F. Markus, Samuel Schlatter, and Iain A. Anderson. "Soft dielectric elastomer oscillators driving bioinspired robots." Mary Ann Liebert, 2017. https://tud.qucosa.de/id/qucosa%3A32850.
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Entirely soft robots with animal-like behavior and integrated artificial nervous systems will open up totally new perspectives and applications. To produce them we must integrate control and actuation in the same soft structure. Soft actuators (e.g. pneumatic, and hydraulic) exist but electronics are hard and stiff and remotely located. We present novel soft, electronicsfree dielectric elastomer oscillators, able to drive bioinspired robots. As a demonstrator we present a robot that mimics the crawling motion of the caterpillar, with integrated artificial nervous system, soft actuators and without any conventional stiff electronic parts. Supplied with an external DC voltage, the robot autonomously generates all signals necessary to drive its dielectric elastomer actuators, and translates an in-plane electromechanical oscillation into a crawling locomotion movement. Thereby, all functional and supporting parts are made of polymer materials and carbon. Besides the basic design of this first electronic-free, biomimetic robot we present prospects to control the general behavior of such robots. The absence of conventional stiff electronics and the exclusive use of polymeric materials will provide a large step towards real animal-like robots, compliant human machine interfaces and a new class of distributed, neuron-like internal control for robotic systems.
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Sanan, Siddharth. "Soft Inflatable Robots for Safe Physical Human Interaction." Research Showcase @ CMU, 2013. http://repository.cmu.edu/dissertations/303.
Full textAbstract:
Robots that can operate in human environments in a safe and robust manner would be of great benefit to society, due to their immense potential for providing assistance to humans. However, robots have seen limited application outside of the industrial setting in environments such as homes and hospitals.
We believe a very important factor preventing the cross over of robotic technology from the factory to the house is the issue of safety. The safety issue is usually bypassed in the industrial setting by separation of human and robot workspaces. Such a solution is clearly infeasible for robots that provide assistance to humans. This thesis aims to develop intrinsically safe robots that are suitable for providing assistance to humans. We believe intrinsic safety is important in physical human robot interaction because unintended interactions will occur between humans and robots due to: (a) sharing of workspace, (b) hardware failure (computer crashes, actuator failures), (c) limitations on perception, and (d) limitations on cognition. When such unintended interactions are very fast (collisions), they are beyond the bandwidth limits of practical controllers and only the intrinsic safety characteristics of the system govern the interaction forces that occur. The effects of such interactions with traditional robots could range from persistent discomfort to bone fracture to even serious injuries. Therefore robots that serve in the application domain of human assistance should be able to function with a high tolerance for unintended interactions. This calls for a new design paradigm where operational safety is the primary concern and task accuracy/precision though important are secondary.
In this thesis, we address this new design paradigm by developing robots that have a soft inflatable structure, i.e, inflatable robots. Inflatable robots can improve intrinsic safety characteristics by being extremely lightweight and by including surface compliance (due to the compressibility of air) as well as distributed structural compliance (due to the lower Young’s modulus of the materials used) in the structure. This results in a lower effective inertia during collisions which implies a lower impact force between the inflatable robot and human. Inflatable robots can essentially be manufactured like clothes and can therefore also potentially lower the cost of robots to an extent where personal robots can be an affordable reality.
In this thesis, we present a number of inflatable robot prototypes to address challenges in the area of design and control of such systems. Specific areas addressed are: structural and joint design, payload capacity, pneumatic actuation, state estimation and control. The CMU inflatable arm is used in tasks like wiping and feeding a human to successfully demonstrate the use of inflatable robots for tasks involving close physical human interaction.
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TRUMIC, Maja. "Stiffness Estimation and Adaptive Control for Soft Robots." Doctoral thesis, Università degli Studi di Palermo, 2021. http://hdl.handle.net/10447/479659.
Full text
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TRUMIC, Maja. "STIFFNESS ESTIMATION AND ADAPTIVE CONTROL FOR SOFT ROBOTS." Doctoral thesis, Università degli Studi di Palermo, 2021. http://hdl.handle.net/10447/509120.
Full textAbstract:
Nonostante la sorprendente crescita nello sviluppo dei robot ispirati alla natura, tra cui i cosiddetti soft robot, il potenziale di questi sistemi, che hanno intrinseche capacità di adattamento, non è ancora stato sfruttato a pieno. La ricerca ha principalmente considerato il controllo in retroazione della posizione dei giunti del robot, lasciando la gestione della cedevolezza di questi ultimi ancora in anello aperto. Peraltro, le attuali limitazioni nel processo di produzione degli attuatori a cedevolezza variabile e l'inevitabile variabilità nel tempo degli elementi elastici costitutivi, i quali sono soggetti ad usura e deformazione plastica, rendono il problema della determinazione precisa della rigidezza di giunto ancora oggi una sfida.
In tale ambito, questa tesi pone l'accento sulla stima della rigidezza e sul controllo adattativo dei soft robot, considerando in primis i sistemi articolati e pilotati da attuatori a cedevolezza variabile (VSA) in configurazione antagonista. Ciò viene fatto con l'obiettivo primario di imporre simultaneamente una dinamica desiderata sia per la posizione che per la rigidezza e, conseguentemente, di migliorare la sicurezza fisica e le prestazioni di un soft robot.
Basandosi sulla teoria degli osservatori ad ingresso sconosciuto (UIO), in questo lavoro vengono proposte soluzioni, invasive e non, che consentono di stimare la rigidezza nei robot con attuatori pneumatici o elettromeccanici, soluzioni che nel secondo caso vengono anche validate sperimentalmente. Oltre al vantaggio della linearità e della scalabilità, le suddette soluzioni hanno l'interessante caratteristica di non richiedere l'uso di sensori di coppia o velocità.
Sfruttando così la disponibilità di una stima della rigidezza, il lavoro descrive inoltre dei metodi innovativi per il controllo robusto dei soft robot articolati, il cui schema include un compensatore adattativo e un disaccoppiatore dinamico. Detti metodi possono gestire le incertezze nella conoscenza del modello dinamico del robot e, quando il riferimento della rigidezza è costante o lentamente variabile, anche quelle relative all'attuatore pneumatico. La loro verifica è valutata attraverso delle simulazioni e, nel caso pneumatico, anche per via sperimentale.
Infine, la tesi mostra come estendere le tecniche di controllo adattativo ai sistemi robotici con cedevolezza distribuita lungo l'intero corpo del robot, garantendo formalmente la convergenza del controllore. L'efficacia di questa tecnica adattativa è mostrata attraverso una estensiva simulazione.Although there has been an astonishing increase in the development of nature-inspired robots equipped with compliant features, i.e. soft robots, their full potential has not been exploited yet. One aspect is that the soft robotics research has mainly focused on their position control only, while stiffness is managed in open loop. Moreover, due to the difficulties of achieving consistent production of the actuation systems for soft articulated robots and the time-varying nature of their internal flexible elements, which are subject to plastic deformation over time, it is currently a challenge to precisely determine the joint stiffness. In this regard, the thesis puts an emphasis on stiffness estimation and adaptive control for soft articulated robots driven by antagonistic Variable Stiffness Actuators (VSAs) with the aim to impose the desired dynamics of both position and stiffness, which would finally contribute to the overall safety and improved performance of a soft robot. By building upon Unknown Input Observer (UIO) theory, invasive and non-invasive solutions for estimation of stiffness in pneumatic and electro-mechanical actuators are proposed and in the latter case also experimentally validated. Beyond the linearity and scalability advantage, the approaches have an appealing feature that torque and velocity sensors are not needed. Once the stiffness is determined, innovative control approaches are introduced for soft articulated robots comprising an adaptive compensator and a dynamic decoupler. The solutions are able to cope with uncertainties of the robot dynamic model and, when the desired stiffness is constant or slowly-varying, also of the pneumatic actuator. Their verification is performed via simulations and then the pneumatic one is successfully tested on an experimental setup. Finally, the thesis shows via extensive simulations the effectiveness of adaptive technique applied to soft-bodied robots, previously deriving the sufficient and necessary conditions for the controller convergence.
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Ying, Min. "A Soft-Body Interconnect For Self-Reconfigurable Modular Robots." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/234.
Full textAbstract:
Disaster support and recovery generally involve highly irregular and dangerous environments. Modular robots are a salient solution to support search and rescue efforts but are still limited to do their reliance on a rigid structure design. To enhance flexibility and resilience to damage, a soft-body interconnection mechanism for self-reconfigurable modular robotic systems has been developed. The soft-body interconnection mechanism utilizes elastomeric polymers instead of a rigid body. Hence, it is capable of deforming under extreme loads without damage. This thesis presents the work completed towards the realization of a soft-body interconnection mechanism. The functional requirements of the soft-body mechanism were broken down into two separate modules for extension and capture. An initial simulation demonstrated the inability of using a simulated model made of hypo-elastic materials as a basis for design. Hence, an iterative design process was used to develop an initial extension and capture soft-body mechanisms that conformed to the desired performance parameters. An empirical study which varied multiple structural parameters was then completed with the initial extension and capture soft-body mechanisms as a basis for the modified designs. The data from the study was correlated with measured performance data with resulted in diagrams useful for the optimal design of soft-body extension and capture mechanisms. The use of the diagrams for design was demonstrated in the design and development of a soft-body interconnection mechanism for an in-house designed small hard shell modular robot system.
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Yang, Hee Doo. "Design, Manufacturing, and Control of Soft and Soft/Rigid Hybrid Pneumatic Robotic Systems." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100635.
Full textAbstract:
Soft robotic systems have recently been considered as a new approach that is in principle better suited for tasks where safety and adaptability are important. That is because soft materials are inherently compliant and resilient in the event of collisions. They are also lightweight and can be low-cost; in general, soft robots have the potential to achieve many tasks that were not previously possible with traditional robotic systems.
In this paper, we propose a new manufacturing process for creating multi-chambered pneumatic actuators and robots. We focus on using fabric as the primary structural material, but plastic films can be used instead of textiles as well. We introduce two different methods to create layered bellows actuators, which can be made with a heat press machine or in an oven. We also describe origami-like actuators with possible corner structures. Moreover, the fabrication process permits the creation of soft and soft/rigid hybrid robotic systems, and enables the easy integration of sensors into these robots. We analyze various textiles that are possibly used with this method, and model bellows actuators including operating force, restoring force, and estimated geometry with multiple bellows. We then demonstrate the process by showing a bellows actuator with an embedded sensor and other fabricated structures and robots.
We next present a new design of a multi-DOF soft/rigid hybrid robotic manipulator. It contains a revolute actuator and several roll-pitch actuators which are arranged in series. To control the manipulator, we use a new variant of the piece-wise constant curvature (PCC) model. The robot can be controlled using forward and inverse kinematics with embedded inertial measurement units (IMUs). A bellows actuator, which is a subcomponent of the manipulator, is modeled with a variable-stiffness spring, and we use the model to predict the behavior of the actuator. With the model, the roll-pitch actuator stiffnesses are measured in all directions through applying forces and torques. The stiffness is used to predict the behavior of the end effector. The robotic system introduced achieved errors of less than 5% when compared to the models, and positioning accuracies of better than 1cm.Doctor of Philosophy
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Coevoet, Eulalie. "Optimization-based inverse model of soft robots, with contact handling." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I002/document.
Full textAbstract:
La robotique souple s’inspire de la nature, de la manière dont les organismes vivants se déplacent et adaptent leur forme à leur environnement. Contrairement aux robots traditionnels, les robots souples accomplissent des tâches avec plus de flexibilité. Les matériaux souples avec lesquels ils sont construits les rendent plus sûrs pour des environnements fragiles.Cependant, le domaine de la robotique souple pose de nouveaux défis, en particulier pour la modélisation et le contrôle. Dans cette thèse, nous visons à fournir des méthodes génériques pour leur modélisation. Les méthodes sont basées sur la méthode des éléments finis pour capturer les déformations de la structure du robot, et de son environnement, quand il est déformable. Nous formulons le problème de leur cinématique inverse et dynamique inverse comme un programme d’optimisation, permettant de gérer facilement des contraintes aux actionneurs et des problèmes de singularité. Nous sommes en mesure de contrôler plusieurs types d’actionnement, tels que les actionnements par câbles, pneumatiques et hydrauliques.De plus, la plupart des applications impliquent une interaction du robot avec des obstacles. Or, la cinématique des robots souples dépend fortement des facteurs environnementaux. Nous proposons ainsi de nouvelles méthodes qui prennent en compte les contacts dans le processus d’optimisation. Enfin, nous proposons de contrôler certaines tâches de locomotion et de préhension nécessitant l’utilisation de contacts frottants (statique). Nous accordons une attention particulière à fournir des solutions avec des performances temps réel, permettant un contrôle en ligne des robots dans des environnements changeantSoft robotics draws its inspiration from nature, from the way living organisms move and adapt their shape to their environment. In opposition to traditional rigid robots, soft robots are built from highly compliant materials, allowing them to accomplish tasks with more flexibility. They are safer when working in fragile environment, which allows for potential use of soft robotics in the fields of manufacturing and medicine.Yet, the field of soft robotics brings new challenges, in particular for modeling and control. Within this thesis we aim at providing generic methods for soft robot modeling, without assumptions on the geometry. The methods are based on the finite element method to capture the deformations of the robot’s structure and of its environment when deformable. We formulate the problem of their inverse kinematics and dynamics as optimization programs, allowing easy handling of constraints on actuation and singularity problems. We are able to control several types of actuation, such as cable, pneumatic and hydraulic actuations.Moreover, most of the applications involve interaction of the robot with obstacles. Yet soft robots kinematics is highly dependent on environmental factors. We propose new methods that include contacts into the optimization process. These methods make an important step as we think that the knowledge of contacts in the modeling is all the more important. Finally, we propose to control some soft robots during locomotion and grasping tasks which require the use of contact with static friction. We give a particular attention to provide solutions with real-time performance, allowing online control in evolving environments
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Marchese, Andrew D. (Andrew Dominic). "Design, fabrication, and control of soft robots with fluidic elastomer actuators." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/97807.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 223-236).
The goal of this thesis is to explore how autonomous robotic systems can be created with soft elastomer bodies powered by fluids. In this thesis we innovate in the design, fabrication, control, and experimental validation of both single and multi-segment soft fluidic elastomer robots. First, this thesis describes an autonomous fluidic elastomer robot that is both self-contained and capable of rapid, continuum body motion. Specifically, the design, modeling, fabrication, and control of a soft fish is detailed, focusing on enabling the robot to perform rapid escape responses. The robot employs a compliant body with embedded actuators emulating the slender anatomical form of a fish. In addition, the robot has a novel fluidic actuation system that drives body motion and has all the subsystems of a traditional robot on-board: power, actuation, processing, and control. At the core of the fish's soft body is an array of Fluidic Elastomer Actuators (FEAs). The fish is designed to emulate escape responses in addition to forward swimming because such maneuvers require rapid body accelerations and continuum body motion. These maneuvers showcase the performance capabilities of this self-contained robot. The kinematics and controllability of the robot during simulated escape response maneuvers are analyzed and compared to studies on biological fish. During escape responses, the soft-bodied robot is shown to have similar input-output relationships to those observed in biological fish. The major implication of this portion of the thesis is that a soft fluidic elastomer robot is shown to be both self-contained and capable of rapid body motion. Next, this thesis provides an approach to planar manipulation using soft fluidic elastomer robots. That is, novel approaches to design, fabrication, kinematic modeling, power, control, and planning as well as extensive experimental evaluations with multiple manipulator prototypes are presented. More specifically, three viable manipulator morphologies composed entirely from soft silicone rubber are explored, and these morphologies are differentiated by their actuator structures, namely: ribbed, cylindrical, and pleated. Additionally, three distinct casting-based fabrication processes are explored: lamination-based casting, retractable-pin-based casting, and lost-wax- based casting. Furthermore, two ways of fabricating a multiple DOF manipulator are explored: casting the complete manipulator as a whole, and casting single DOF segments with subsequent concatenation. An approach to closed-loop configuration control is presented using a piecewise constant curvature kinematic model, real-time localization data, and novel fluidic drive cylinders which power actuation. Multi-segment forward and inverse kinematic algorithms are developed and combined with the configuration controller to provide reliable task-space position control. Building on these developments, a suite of task-space planners are presented to demonstrate new autonomous capabilities from these soft robots such as: (i) tracking a path in free-space, (ii) maneuvering in confined environments, and (iii) grasping and placing objects. Extensive evaluations of these capabilities with physical prototypes demonstrate that manipulation with soft fluidic elastomer robots is viable. Lastly, this thesis presents a robotic manipulation system capable of autonomously positioning a multi-segment soft fluidic elastomer robot in three dimensions while subject to the self-loading effects of gravity. Specifically, an extremely soft robotic manipulator morphology that is composed entirely from low durometer elastomer, powered by pressurized air, and designed to be both modular and durable is presented. To understand the deformation of a single arm segment, a static physics-based model is developed and experimentally validated. Then, to kinematically model the multi-segment manipulator, a piece-wise constant curvature assumption consistent with more traditional continuum manipulators is used. Additionally, a complete fabrication process for this new manipulator is defined and used to make multiple functional prototypes. In order to power the robot's spatial actuation, a high capacity fluidic drive cylinder array is implemented, providing continuously variable, closed-circuit gas delivery. Next, using real-time localization data, a processing and control algorithm is developed that generates realizable kinematic curvature trajectories and controls the manipulator's configuration along these trajectories. A dynamic model for this multi-body fluidic elastomer manipulator is also developed along with a strategy for independently identifying all unknown components of the system: the soft manipulator, its distributed fluidic elastomer actuators, as well as its drive cylinders. Next, using this model and trajectory optimization techniques locally-optimal, open-loop control policies are found. Lastly, new capabilities offered by this soft fluidic elastomer manipulation system are validated with extensive physical experiments. These are: (i) entering and advancing through confined three-dimensional environments, (ii) conforming to goal shape-configurations within a sagittal plane under closed-loop control, and (iii) performing dynamic maneuvers we call grabs.
by Andrew D. Marchese.
Ph. D.
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Pan, Min, Zhe Hao, Chenggang Yuan, and Andrew Plummer. "Development and control of smart pneumatic mckibben muscles for soft robots." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71262.
Full textAbstract:
Animals exploit soft structures to move smoothly and effectively in complex natural environments. These capabilities have inspired robotic engineers to incorporate soft actuating technologies into their designs. Developing soft muscle-like actuation technology is one of the grand challenges in the creation of soft-body robots that can move, deform their body, and modulate body stiffness. This paper presents the development of smart pneumatic McKibben muscles woven and reinforced by using conductive
insulated wires to equip the muscles with an inherent sensing capability, in which the deformation of the muscles can be effectively measured by calculating the change of wire inductance. Sensing performance of a variety of weaving angles is investigated. The ideal McKibben muscle models are used for analysing muscle performance and sensing accuracy. The experimental results show that the contraction of the muscles is proportional to the measured change of inductance. This relationship is applied to a PID control system to control the contraction of smart muscles in simulation, and good control performance is achieved. The creation of smart muscles with an inherent sensing capability and a good controllability is promising for operation of future soft robots.
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Lum, Guo Zhan. "Optimal Design of Miniature Flexural and Soft Robotic Mechanisms." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1090.
Full textAbstract:
Compliant mechanisms are flexible structures that utilize elastic deformation to achieve their desired motions. Using this unique mode of actuation, the compliant mechanisms have two distinct advantages over traditional rigid machines: (1) They can create highly repeatable motions that are critical for many high precision applications. (2) Their high degrees-of-freedom motions have the potential to achieve mechanical functionalities that are beyond traditional machines, making them especially appealing for miniature robots that are currently limited to only having simple rigid-body-motions and gripping functionalities. Unfortunately, despite the potential of compliant mechanisms, there are still several key challenges that restrict them from realizing their full potential. To facilitate this discussion, we first divide the compliant mechanisms into two categories: (1) the stiffer flexural mechanisms that are ideal for high precision applications, and (2) the more compliant miniature soft robots that can reshape their geometries to achieve highly complex mechanical functionalities. The key limitation for existing flexural mechanisms is that their stiffness and dynamic properties cannot be optimized when they have multi-degrees-of-freedom. This limitation has severely crippled the performance of flexural mechanisms because their stiffness and dynamic properties dictate their workspace, transient responses and capabilities to reject disturbances. On the other hand, miniature soft robots that have overall dimensions smaller than 1 cm, are unable to achieve their full potential because existing works do not have a systematic approach to determine the required design and control signals for the robots to generate their desired time-varying shapes.
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Mirano, Geronimo (Geronimo J. ). "Jacobian-based control of soft robots for manipulation using implicit surface models." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113126.
Full textAbstract:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (page 47).
Soft robot hands offer numerous advantages over rigid ones for manipulation, including robustness and safety. Yet, compared to rigid robots, soft robots are characterized by continuous mechanics, and finite-element approximations with many degrees of freedom present a significant obstacle for modern control approaches. The central question my thesis explores is whether we can capture the benefits of soft robot hands with relatively simple dynamical models. Specifically, we demonstrate a very simple model of a 2D soft manipulator that uses pulleys and cables to model deformable surfaces. This model captures much of the qualitative behavior of soft membranes, while also proving amenable to modern control techniques. We validate this model physically using a hardware set-up. We then demonstrate a simple quasi-static Jacobian controller which solves a second-order cone program to achieve the task of in-hand object repositioning.
by Geronimo Mirano.
M. Eng.
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Wilson, Joshua Parker. "Extending Time Until Failure During Leaking in Inflatable, Pneumatically Actuated Soft Robots." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6264.
Full textAbstract:
Soft robots and particularly inflatable robots are of interest because they are lightweight, compact, robust to impact, and can interact with humans and their environment relatively safely compared to rigid and heavy traditional robots. Improved safety is due to their low mass that results in low-energy collisions and their compliant, soft construction. Inflatable robots (which are a type of soft robot) are also robust to impact and have a high torque to weight ratio. As a result inflatable robots may be used for many applications such as space exploration, search and rescue, and human-robot interaction. One of the potential problems with inflatable or pneumatically actuated robots is air leaking from the structural or actuation chambers. In this thesis methods are demonstrated to detect leaks in the structural and actuation chambers of inflatable and pneumatically actuated robots. It is then demonstrated that leaks can be slowed by lowering a target pressure which affects joint stiffness to prolong the life of the system. To demonstrate the effects of lowering the target pressure it is first shown that there exists a trade-off between the commanded target pressures at steady-state and the steady-state error at the robot end effector under normal operation. It is then shown that lowering the target pressure (which is related to stiffness) can extend the operational life of the system when compressed air is a limited resource. For actuator leaks a lower target pressure for the leaking joint is used to demonstrate the trade-off between slowing the leak rate and system performance. For structural leaks a novel control algorithm is demonstrated to lower target pressure as much as possible to slow the leak while maintaining a user specified level of accuracy. The method developed for structural leaks extends the operational life of the robot. Long-term error during operation is decreased by as much as 50% of the steady-state error at the end effector when compared to performance during a leak without the control algorithm. For actuation leaks in a joint with a high-torque load the possibility of a 30% increase in operation time while only increasing steady-state error by 2 cm on average is demonstrated. For a joint with a low-torque load it is shown that up to a 300% increase in operation time with less than 1 cm increased steady-state error is possible. The work presented in this thesis demonstrates that varying stiffness may be used to extend the operational life of a robot when a leak has occurred. The work discussed here could be used to extend the available operation time of pneumatic robots. The methods and principles presented here could also be adapted for use on other types of robots to preserve limited system resources (e.g., electrical power) and extend their operation time.
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TALAMINI, JACOPO. "Artificial Intelligence Strategies in Multi-agent Reinforcement Learning and Robotic Agents Evolution." Doctoral thesis, Università degli Studi di Trieste, 2021. http://hdl.handle.net/11368/2982151.
Full textAbstract:
Most of the theoretical foundations which have contributed to shape Artificial Intelligence (AI) as we know it come from the last century.
The technological advancement of the last decades however, mainly in the form of faster parallel computation, larger memory units, and Big Data, has dramatically increased the popularity of AI within the research community.
Far from being only a pure object of research, AI has been successful in many fields of applications, and it has become deeply integrated into our daily experiences.
We live in a society in which on-demand content suggestions are tailored for each customer, where it is possible to order products online by chatting with bots.
Smart devices adapts to the owner behavior, the stock exchange brokers are algorithm based on predictive models, and the computers are able to discover new medicines and new materials.
Despite the amount of knowledge acquired on AI, there are still many aspects of it that we do not fully understand, such as the interplays within multiple autonomous agents scenarios, in which AIs learn and interact in a shared environment, while possibly being subjected to different goals.
In these scenarios the communication and the regulation of the autonomous agents are both extremely relevant aspects.
In this work we analyze in which way the language expressiveness affect how agents learn to communicate, to which extent the learned communication is affected by the scenario, and how to allow them to learn the optimal one.
We then investigate which communication strategies might be developed in different scenarios when driven by the individual goal, which might lead to improved equality in a cooperative scenario, or more inequality in a competitive one.
Another aspect that we consider is the ethics of multiple agents, to which we contribute by proposing a way to discourage unethical behaviors without disabling them, but instead enforcing a set of flexible rules to guide the agents learning.
AI success can be determined by its ability to adapt, which is an aspect that we consider in this work, relatively to the adaptation of autonomous soft robotic agents.
Soft robots are a new generation of nature-inspired robots more versatile and adaptable than the ones made of rigid joints, but the design and the control of soft robots can not be easily done manually.
To this extent we investigate the possibility of mimicking the evolution of biological beings, by adopting evolutionary meta-heuristics for optimizing these robots.
Specifically we propose to evolve a control algorithm that leverages the body complexity inherent to the soft robots through sensory data collected from the environment.
Considering the problem of designing adaptable soft robots, we propose an approach that allows to automatically synthesize robotic agents for solving different tasks, without needing to know them in advance.
Agent-based scenarios are powerful research tools that can be adopted also for approximating the behavior of biological actors.
Based on this possibility, we propose a model for the assessment of the publishing system indicators, which are currently used to evaluate authors and journals.
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Hockings, Nicholas. "Material and mechanical emulation of the human hand." Thesis, University of Bath, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720651.
Full textAbstract:
The hands and feet account for half of the complexity of the musculoskeletal system, while the skin of the hand is specialised with many important structures. Much of the subtlety of the mechanism of the hand lies in the soft tissues, and the tactile and proprioceptive sensitivity depends on the large number of mechanoreceptors embedded in specific structures of the soft tissues. This thesis investigates synthetic materials and manufacturing techniques to enable building robots that reproduce the biomechanics and tactile sensitivity of vertebrates – histomimetic robotics. The material and mechanical anatomy of the hand is reviewed, highlighting difficulty of numerical measurement in soft-tissue anatomy, and the predictive nature of descriptive anatomical knowledge. The biomechanical mechanisms of the hand and their support of sensorimotor control are presented. A palate of materials and layup techniques are identified for emulating ligaments, joint surfaces, tendon networks, sheaths, soft matrices, and dermal structures. A method for thermoplastically drawing fine elastic fibres, with liquid metal amalgam cores, for connecting embedded sensors is demonstrated. The performance requirements of skeletal muscles are identified. Two classes of muscle-like bulk MEMS electrostatic actuators are shown theoretically to be capable of meeting these requirements. Means to manufacture them, and their additional application as mechanoreceptors are described. A novel machine perception algorithm is outlined as a solution to the problem of measuring soft tissue anatomy, CAD/CAE/CNC for layup of histomimetic robots, and sensory perception by such robots. The results of the work support the view that histomimetic robotics is a viable approach, and identify a number of areas for further investigation including: polymer modification by graft-polymerisation, automated layup tools, and machine perception.
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Wu, You Ph D. Massachusetts Institute of Technology. "Low-cost soft sensors and robots for leak detection in operating water pipes." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/118022.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 243-247).
Every day, about 20% of the clean water produced in the world is lost due to pipe leaks. Due to limitations in available technologies, most of the leaks are either not found, or found too late. Every year, there are 240,000 water pipe breaks in the US, and many of them cause sinkholes and other severe damage to the infrastructure. Water utilities need methods for detecting and locating such leaks before they become big breaks, so that they can perform preventative maintenance. This is to save water and protect infrastructure. This thesis presents the design, analysis, fabrication and field test validations of such a solution. I developed soft robots for early detection of leaks in water pipes when the water service is on. This work introduces four key contributions: (1) Design, fabrication and field validations of soft robots for operating water pipes (2) Design, fabrication and field validations of a tactile sensor for detecting leaks in operating water pipes (3) Differentiate leaks from false positives with a low-cost soft bending angle sensor (4) A practical, minimalism approach to the in-pipe localization, specifically for soft robots. The results are validated in simulations, lab, and field experiments. Those sensors and robots are designed to be low-cost and scalable. They are fabricated with ordinary material with ordinary tools. It is a sub-500-dollar solution to a multi-billion-dollar water and infrastructure problem.
by You Wu.
Ph. D.