Dissertations / Theses: 'Pneumatic actuation'

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Yusop, M. Y. Mohd. "Energy saving for pneumatic actuation using dynamic model prediction." Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/56066/.

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This research investigates a novel method for energy saving in a point-to-point actuation of a pneumatic system. The method predicts the system's actuation using the Gas Law and the actuator model, and commits air supply cut-off at the time when the energy in the actuator is sufficient to complete the actuation task. Experimental implementation is compared with simulation. The effect of the method is compared with conventional no cut-off and end-stroke cut-off actuations. Lumped and finite difference methods are used for transmission line and system actuation modelling. The transmission line, actuator and control valves are modelled and integrated for the system actuation simulation and comparisons between simulation and measured data are performed. Pressure oscillation in the transmission line exists and is captured by stimulating the air dynamics using a new transmission line experimental method. The friction model of the pneumatic actuator is determined by experiment and applied to the energy saving control system as well as the computer modelling algorithm. The determination of pneumatic transmission line bulk modulus is performed through experiment due to the confidentiality of Young's modulus value needed for its calculation. Significant effect has been achieved in implementation and it is found that cut off at end-stroke and cut-off using model prediction can reduce the amount of air potential energy wasted in conventional actuation by up to 43.5% and 80.2% respectively. However the actuation time of predicted cut-off increases by up to 25%.

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Wang, Yi. "MRI-Compatible Pneumatic Actuation Control Algorithm Evaluation and Test System Development." Digital WPI, 2010. https://digitalcommons.wpi.edu/etd-theses/1041.

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"This thesis presents the development of a magnetic resonance imaging (MRI) compatible pneumatic actuation test system regulated by piezoelectric valve for image guided robotic intervention. After comparing pneumatic, hydraulic and piezoelectric MRI-compatible actuation technologies, I present a piezoelectric valve regulated pneumatic actuation system consisted of PC, custom servo board driver, piezoelectric valves, sensors and pneumatic cylinder. This system was proposed to investigate the control schemes of a modular actuator, which provides fully MRI-compatible actuation; the initial goal is to control our MRI-compatible prostate biopsy robot, but the controller and system architecture are suited to a wide range of image guided surgical application. I present the mathematical modeling of the pressure regulating valve with time delay and the pneumatic cylinder. Three different sliding mode control (SMC) schemes are proposed to compare the system performance. Simulation results are presented to validate the control algorithm. Practical tests with parameters determined from simulation show that the system performance attained the goal. A novel MRI- compatible locking device for the pneumatic actuator was developed to provide safe lock function as the pneumatic actuator fully stopped."

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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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Kunt, Cengiz O. "Analysis of high speed pneumatic actuation systems under rotary directional on-off flow control /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487596807822691.

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Bubert, Edward A. "Highly extensible skin for a variable wing-span morphing aircraft utilizing pneumatic artificial muscle actuation." College Park, Md. : University of Maryland, 2009. http://hdl.handle.net/1903/9332.

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Thesis (M.S.) -- University of Maryland, College Park, 2009.
Thesis research directed by: Dept. of Aerospace Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

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Wirekoh, Jackson O. "Development of Soft Actuation Systems for Use in Human-Centered Applications." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1124.

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In recent years, soft materials have seen increased prevalence in the design of robotic systems and wearables capable of addressing the needs of individuals living with disabilities. In particular, pneumatic artificial muscles (PAMs) have readily been employed in place of electromagnetic actuators due to their ability to produce large forces and motions, while still remaining lightweight, compact, and flexible. Due to the inherent nonlinearity of PAMs however, additional external or embedded sensors must be utilized in order to effectively control the overall system. In the case of external sensors, the bulkiness of the overall system is increased, which places limits on the system’s design. Meanwhile, the traditional cylindrical form factor of PAMs limits their ability to remain compact and results in overly complex fabrication processes when embedded fibers and/or sensing elements are required to provide efficient actuation and control. In order to overcome these limitations, this thesis proposed the design of flat pneumatic artificial muscles (FPAMs) capable of being fabricated using a simple layered manufacturing process, in which water-soluble masks were utilized to create collapsed air chambers. Furthermore, hyperelastic deformation models were developed to approximate the mechanical performance of the FPAMs and were verified through experimental characterization. The feasibility of these design techniques to meet the requirements of human centered applications, including the suppression of hand tremors and catheter ablation procedures, was explored and the potential for these soft actuation systems to act as solutions in other real world applications was demonstrated. We expect the design, fabrication, and modeling techniques developed in this thesis to aid in the development of future wearable devices and motivate new methods for researchers to employ soft pneumatic systems as solutions in human-centered applications.

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ASSAD, MARILIA MAURELL. "CHARACTERIZATION OF COMPONENTS DYNAMIC BEHAVIOR IN A PNEUMATIC ACTUATION SYSTEM FOR CONTROL APPLICATIONS ON REDUCED SCALE MECHANICAL SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2013. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=37189@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Sistemas pneumáticos são equipamentos leves, baratos, limpos e de baixo risco, sendo apropriados para aplicações que necessitem de força e rapidez de resposta. Por outro lado, esse tipo de sistema apresenta restrições devido à principal característica do ar: sua compressibilidade confere efeitos não lineares ao sistema, desde um escoamento turbulento pelas válvulas de controle até sua atuação dentro do cilindro – a qual inclui alta sensibilidade ao atrito e volumes inativos durante o curso do pistão. Essas características particulares dificultam seu controle e posicionamento preciso e limitam sua aplicação, principalmente considerando seu emprego em um mecanismo tipo Plataforma de Stewart em escala reduzida. No presente trabalho apresenta-se a modelagem, simulação computacional e análise experimental do comportamento dinâmico de um sistema de atuação pneumático que inclui uma válvula de controle de vazão não convencional, composta de quatro válvulas proporcionais, e um atuador com haste simples de dupla ação. O objetivo deste trabalho é, baseado nos resultados experimentais, determinar as características desses componentes para desenvolver estratégias de controle em tempo real capazes de minimizar os efeitos das não linearidades típicas, visando sua utilização no mecanismo anteriormente mencionado.
Pneumatic equipment is lightweight, cheap, clean and low-risk, being suitable for applications that require strength and high responsiveness. Nevertheless, this type of system has some limitations due to the air main feature: its compressibility results in nonlinear effects in the system, from the turbulent flow control valves to its performance inside the cylinder - which includes high sensitivity to friction and dead volumes during the stroke piston. These particular characteristics make its control and precise positioning difficult, limiting its application, especially when considered its use in a mechanism such as a Stewart Platform in a reduced scale. The present paper presents the modeling, computational simulation and experimental analysis of the dynamic behavior of a pneumatic actuation system that includes an unconventional flow control valve, consisting of four proportional valves, and a double acting single rod actuator. The final goal of this work is to, based on experimental results, determine the characteristics of these components in order to develop real-time control strategies which can minimize the effects of those typical nonlinearities for their use in the mechanism mentioned above.

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Kirn, Johannes [Verfasser], Horst [Akademischer Betreuer] [Gutachter] Baier, and Klaus [Gutachter] Drechsler. "Investigation of a shape adaptive aircraft wing leading edge with pneumatic actuation / Johannes Kirn ; Gutachter: Klaus Drechsler, Horst Baier ; Betreuer: Horst Baier." München : Universitätsbibliothek der TU München, 2017. http://d-nb.info/1129874478/34.

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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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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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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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De, Greef Aline. "Towards medical flexible instruments: a contribution to the study of flexible fluidic actuators." Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210073.

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The medical community has expressed a need for flexible medical instruments. Hence, this work investigates the possibility to use "flexible fluidic actuators" to develop such flexible instruments. These actuators are driven by fluid, i.e. gas or liquid, and present a flexible structure, i.e. an elastically deformable and/or inflatable structure. Different aspects of the study of these actuators have been tackled in the present work:

• A literature review of these actuators has been established. It has allowed to identify the different types of motion that these actuators can develop as well as the design principles underlying. This review can help to develop flexible instruments based on flexible fluidic actuators.

• A test bench has been developed to characterize the flexible fluidic actuators.

• A interesting measuring concept has been implemented and experimentally validated on a specific flexible fluidic actuator (the "Pneumatic Balloon Actuator", PBA). Ac- cording to this principle, the measurements of the pressure and of the volume of fluid supplied to the actuator allow to determine the displacement of the actuator and the force it develops. This means being able to determine the displacement of a flexible fluidic actuator and the force it develops without using a displacement sensor or a force sensor. This principle is interesting for medical applications inside the human body, for which measuring the force applied by the organs to the surgical tools remains a problem.

The study of this principle paves the way for a lot of future works such as the implemen- tation and the testing of this principle on more complex structures or in a control loop in order to control the displacement of the actuator (or the force it develops) without using a displacement or a force sensor.

• A 2D-model of the PBA has been established and has helped to better understand the physics underlying the behaviour of this actuator.

• A miniaturization work has been performed on a particular kind of flexible fluidic actu- ator: the Pleated Pneumatic Artificial Muscle (PPAM). This miniaturization study has been made on this type of actuator because, according to theoretical models, minia- turized PPAMs, whose dimensions are small enough to be inserted into MIS medical instruments, could be able to develop the forces required to allow the instruments to perform most surgical actions. The achieved miniaturized muscles have a design similar to that of the third generation PPAMs developed at the VUB and present a total length of about 90 mm and an outer diameter at rest of about 15 mm. One of the developed miniaturized PPAMs has been pressurized at p = 1 bar and it was able to develop a pulling force F = 100 N while producing a contraction of 4 %.

Propositions have been made regarding a further miniaturization of the muscles.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

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Thomas, Michael Brian. "Advanced servo control of a pneumatic actuator." Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1070373448.

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Thesis (Ph. D.)--Ohio State University, 2003.
Title from first page of PDF file. Document formatted into pages; contains xix, 222 p.; also includes graphics (some col.) Includes bibliographical references (p. 215-222). Available online via OhioLINK's ETD Center

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Tillett, N. D. "Pneumatic actuator for use in horticultural robots." Thesis, University of Bath, 1998. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390547.

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Xiang, Fulin. "Block-Oriented Nonlinear Control of Pneumatic Actuator Systems." Doctoral thesis, Stockholm, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3157.

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Mohorcic, John Francis. "Pressure-based Impedance Control of a Pneumatic Actuator." Cleveland State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=csu1591188440286793.

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Helgeland, Erlend. "Sliding Mode Control of an Electro-Pneumatic Clutch Actuator." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8852.

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This report investigates proportional-derivative (PD) controller and different versions of sliding mode controllers, including a 2-sliding mode controller invented by Arie Levant, applied to a pneumatic actuator on a truck clutch, The purpose of the clutch system is to develop a transmission system consisting of a normal clutch and transmission controlled automatically as an automatic gearbox, called automated manual transmission. The goal is to increase driver comfort and performance, as well as reduce fuel consumption. It is put an effort in implementing an accurate simulation model of the clutch system in Matlab Simulink. The model output includes clutch position, velocity and acceleration, actuator chamber pressure and temperature. The accuracy of the model developed is assumed to be accurate enough for control design. The only measurement available is position measurement, because more sensors increase cost. The measurement noise is low, which enables direct use of the position measurement for control. For the controllers and other parts of the control system that is dependent on velocity, acceleration or pressure estimates, the measurement has to be differentiated. Differentiation of noisy signals is problematic, therefore filters have to be used. In this report a first order low pass filter differentiator is compared to a robust differentiator, which is inspired by higher order sliding modes and developed by Arie Levant. The reason for comparing it with a very simple filter is the simplicity of the first order filter. It is easy to understand and tune. The performance of the robust differentiator is in this application not better than the first order filter. Therefore the first order filter is used in the tests. A simplified version of the simulation model is used in the design of the controllers. A PD controller with limited derivative action is tuned on the basis of a linearized version of the control model. PD controllers have turned out to perform well and is suitable for comparison, because they are independent of measurement filters, well known and have well established design methods. The PD controller is compared to different sliding mode controllers. The most promising sliding mode controller, which is a boundary layer controller with variable boundary layer width, is tested thoroughly on the simulation model. Different tests where the simulation model parameters are altered, are performed to investigate the robustness and performance properties of the controllers. The most promising sliding mode controller were supposed to be tested against the PD controller on a test truck at Kongsberg Automotive. New and faster valves were supposed to be tested in the truck. Unfortunately they did not arrived in time for the test and in addition, the driver circuit of the older and slower valves broke down under the test startup. Therefore the real tests could not be accomplished. A brief overview of the planned field tests is given. The PD controller and sliding mode controller are compared in a view focusing on robustness. It is found that the ideal sliding mode controller is highly robust, but not usable in practise for this application. The developed variable boundary layer sliding mode controller performs better than the PD controller on the simulation model. The reason may be that it is tailored to the reference trajectory used, as opposed to the PD controller which is tuned using Bode diagrams, gain and phase margins. Both controllers possess approximately the same robustness properties.

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Schönning, Johan, and Sebastian Zamani. "Modeling and Control of Opticruise - a Pneumatic Force Actuator." Thesis, KTH, Reglerteknik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-106232.

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Opticruise is an automated transmission system for manual gear boxes. The length stroke is a part of the Opticruise system, in which the mechanical gear shifting process is performed by pneumatic actuators. To reduce piston velocity before the cylinder walls are reached, an oil damper is attached to the pneumatic actuator. The purpose of this thesis is to evaluate if the oil damper can be replaced by a pneumatic feedback control law, a model predictive control scheme or an alternative mechanical construction; in the interest of cost reduction, robustness, shift comfort and shift time. To be able to do a systematic analysis, a mathematical model of the length stroke is developed. The model, developed using a length stroke that is not mounted on a truck, captures the essential dynamics of the system and is used to evaluate control strategies and investigate system properties. As the delay in feedback information from the different sensors is larger than the process time constant, a pneumatic feedback control law is discarded. A model predictive control law is found difficult to realize since the system properties, when the length stroke is placed on a truck, are different in every gearshift. Instead a mechanical construction proposing smaller final chamber volumes is discussed. This solution turns out to be a cost-effective way to achieve a good velocity reduction before the end position. Since feedback control is still an interesting option for future gear shifting systems, the requirements on sensors, controllers and actuators for achieving good controller performance is briefly discussed.

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Ke, Jia. "Improvement of energy efficiency of pneumatic cylinder actuator systems." Thesis, University of Liverpool, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437508.

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Merkelbach, Stephan [Verfasser]. "Analysis of the Economic and Ecological Properties of Pneumatic Actuator Systems with Pneumatic Transformers / Stephan Merkelbach." Düren : Shaker, 2020. http://d-nb.info/1205239340/34.

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Hari, shankar lal das Ganesh kumar. "Design, modeling and control of inherently compliant actuators with a special consideration on agonist-anthropomorphic configuration." Thesis, Toulouse, INSA, 2016. http://www.theses.fr/2016ISAT0030/document.

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Conception, modélisation et contrôle des actionneurs intrinsèquement conformes avec une considération particulière sur la configuration anthropomorphe agoniste-antagoniste "La recherche vise à la conception, la modélisation et le contrôle des actionneurs intrinsèquement conformes pour les systèmes anthropomorphes.La première partie du travail se concentre sur l'étude de divers Existants et rechercher la possibilité d'autres actionneurs autres que les moteurs électriques conventionnels.Une attention particulière est accordée aux actionneurs souples à base de polymères élctroactifs qui ont un bon potentiel dans les futures applications robotiques. Parallèlement, on a synthétisé un modèle de la dynamique de l'actionneur et du contrôleur basé sur le modèle (MPC et contrôle optimal) pour un bras anthropomorphe 7 Dofs actionné par une paire antagoniste-agoniste de Muscles Artificiels Pneumatiques (PAM) à chaque articulation. Ce modèle et contrôleur est alors intégré dans l'environnement logiciel développé par l'équipe. En utilisant le bras manipulateur anthropomorphe basé sur PAM et le simulateur numérique, des tests sont effectués afin d'évaluer le potentiel de cet actionneur et de comparer avec les capacités du corps humain
Design, modeling and control of inherently compliant actuators with a special consideration on agonist- antagonist anthropomorphic configuration" The research aims at the design, modeling and control of inherently compliant actuators for anthropomorphic systems. The first part of the work focuses on the study of various existing designs and look for the possibility of alternative actuators other than the conventional electric motors. Special attention is given to elctroactive polymer based soft actuators which have good potential in future robotic applications. In parallel, a model of the actuator dynamics and the model-based controller (MPC and optimal control) have been synthesized for an anthropomorphic 7 Dofs arm actuated by antagonist-agonist pair of Pneumatic Artificial Muscles (PAMs) at each joint. Such model and controller is then integrated within the software environment developed by the team. Using the PAMs based anthropomorphic manipulator arm and the numerical simulator, tests are done in order to evaluate the potential of this actuator and compare with the human body capabilities

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Kryštof, Ondřej. "Bezpečnost automatizovaných průmyslových armatur v provozních podmínkách." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254356.

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Choosing suitable and safe valve with accessories depends on general specifications for plant. Using valve for on/off, throttling, back-flow prevention, etc., pressure drop is related with Kv value or leakages from piping systems are main factors for properly valve selection. Valve have to resist chemicals and substances that may change the state, temperature and its fluctuation, pressure, corrosion and erosion. This properties determine pressure class, temperature resistance, connection into pipe and sealing material as gland packing, seats, seal between flange etc. This and other specification, listed in this thesis, can help determine suitable type of valve. This thesis deals construction design of valve and accessories as well. The last chapters are focused on calculation of safety valve and selection safe and appropriate control valve with accessories.

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Schmitt, François. "Méthodes et procédés pour l'assistance à la chirurgie laparoscopique par comanipulation." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAD033.

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Le contexte de cette thèse est le développement d'outils pour améliorer la perception de la raideur des tissus dans le cadre de la chirurgie laparoscopique assistée par comanipulation. Lors de procédures manuelles, cette perception est distordue, notamment par l'effet levier, conséquence des contraintes cinématiques imposées par le trocart. Cette thèse s'articule ainsi autour de deux parties. Dans une première partie, nous étudions l'effet levier et les distorsions qu'il produit dans le cadre d'un outil comanipulé. Nous y introduisons ainsi un modèle permettant l’analyse en raideur d’un outil comanipulé par un chirurgien et un robot. Sur cette base, nous développons une stratégie de compensation pour laquelle nous avons mis en place une expérience de validation. Dans une deuxième partie, nous abordons la conception d’une nouvelle architecture à cinématique RCM, intégrant structure et actionnement pour des applications de robotique légère. Nous présentons notamment une démarche de conception de systèmes origamis articulés produits à l’aide de procédés de fabrication multi-matériaux
The context of this work is the development of tools in order to improve the tissues stiffness perception for cobot-assisted laparoscopic surgery. During manual procedures, this perception is distorted, notably by the fulcrum effect, due to the kinematic constraints induced by the trocar. This thesis is developed in two parts. In a first part, we study the fulcrum effect and how it distorts the perception of a user manipulating the tool in collaboration with a robot. From this model, we propose a strategy in order to compensate for this distortion. A validation experiment for this strategy is then proposed. In a second part, we discuss the design of a new architecture with RCM kinematics, integrating both structure and actuation for lightweight robotic applications. In this context, we present an approach to design articulated origami systems, manufactured using multi-material processes

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Gerschutz, Maria J. "Dynamic Pneumatic Muscle Actuator Control System for an Augmented Orthosis." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1210286543.

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TAHIR, AHMAD MAHMOOD. "DEVELOPMENT OF A SOFT PNEUMATIC ACTUATOR FOR MODULAR ROBOTIC MECHANISMS." Doctoral thesis, Università degli studi di Genova, 2019. http://hdl.handle.net/11567/942314.

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Soft robotics is a widely and rapidly growing field of research today. Soft pneumatic actuators, as a fundamental element in soft robotics, have gained huge popularity and are being employed for the development of soft robots. During the last decade, a variety of hyper-elastic robotic systems have been realized. As the name suggests, such robots are made up of soft materials, and do not have any underlying rigid mechanical structure. These robots are actuated employing various methods like pneumatic, electroactive, jamming etc. Generally, in order to achieve a desired mechanical response to produce required actuation or manipulation, two or more materials having different stiffness are utilized to develop a soft robot. However, this method introduces complications in the fabrication process as well as in further design flexibility and modifications. The current work presents a design scheme of a soft robotic actuator adapting an easier fabrication approach, which is economical and environment friendly as well. The purpose is the realization of a soft pneumatic actuator having functional ability to produce effective actuation, and which is further employable to develop modular and scalable mechanisms. That infers to scrutinize the profile and orientation of the internal actuation cavity and the outer shape of viii the actuator. Utilization of a single material for this actuator has been considered to make this design scheme convenient. A commercial silicone rubber was selected which served for an economical process both in terms of the cost as well as its accommodating fabrication process through molding. In order to obtain the material behavior, ‘Ansys Workbench 17.1 R ’ has been used. Cubic outline for the actuator aided towards the realization of a body shape which can easily be engaged for the development of modular mechanisms employing multiple units. This outer body shape further facilitates to achieve the stability and portability of the actuator. The soft actuator has been named ‘Soft Cubic Module’ based on its external cubic shape. For the internal actuation cavity design, various shapes, such as spherical, elliptical and cylindrical, were examined considering their different sizes and orientations within the cubic module. These internal cavities were simulated in order to achieve single degree of freedom actuation. That means, only one face of the cube is principally required to produce effective deformation. ‘Creo Perametric 3.0 M 130’ has been used to design the model and to evaluate the performance of actuation cavities in terms of effective deformation and the resulting von-mises stress. Out of the simulated profiles, cylindrical cavity with desired outcomes has been further considered to design the soft actuator. ‘Ansys Workbench 17.1 R ’ environment was further used to assess the performance of cylindrical actuation cavity. Evaluation in two different simulation environments helped to validate the initially achieved results. The developed soft cubic actuator was then employed to develop different mechanisms in a single unit configuration as well as multi-unit robotic system developments. This design scheme is considered as the first tool to investigate its capacity to perform certain given tasks in various configurations. Alongside its application as a single unit gripper and a two unit bio-mimetic crawling mechanism, this soft actuator has been employed to realize a four degree ix of freedom robotic mechanism. The formation of this primitive soft robotic four axis mechanism is being further considered to develop an equivalent mechanism similar to the well known Stewart platform, with advantages of compactness, simpler kinematics design, easier control, and lesser cost. Overall, the accomplished results indicate that the design scheme of Soft Cubic Module is helpful in realizing a simple and cost-effective soft pneumatic actuator which is modular and scalable. Another favourable point of this scheme is the use of a single material with convenient fabrication and handling.

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26

Smith, Michael Christopher. "The positioning of a low friction pneumatic actuator using on-off control." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/11921.

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27

Murillo, Jaime. "Design of a Pneumatic Artificial Muscle for Powered Lower Limb Prostheses." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24104.

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Ideal prostheses are defined as artificial limbs that would permit physically impaired individuals freedom of movement and independence rather than a life of disability and dependence. Current lower limb prostheses range from a single mechanical revolute joint to advanced microprocessor controlled mechanisms. Despite the advancement in technology and medicine, current lower limb prostheses are still lacking an actuation element, which prohibits patients from regaining their original mobility and improving their quality of life. This thesis aims to design and test a Pneumatic Artificial Muscle that would actuate lower limb prostheses. This would offer patients the ability to ascend and descend stairs as well as standing up from a sitting position. A comprehensive study of knee biomechanics is first accomplished to characterize the actuation requirement, and subsequently a Pneumatic Artificial Muscle design is proposed. A novel design of muscle end fixtures is presented which would allow the muscle to operate at a gage pressure surpassing 2.76 MPa (i.e. 400 psi) and yield a muscle force that is at least 3 times greater than that produced by any existing equivalent Pneumatic Artificial Muscle. Finally, the proposed Pneumatic Artificial Muscle is tested and validated to verify that it meets the size, weight, kinetic and kinematic requirements of human knee articulation.

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Jeddi, Tehrani Maisam. "Pressure Control of a Pneumatic Actuator Using On/O Solenoid Valves." Thesis, KTH, Reglerteknik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105878.

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Nowadays a very important aspect in heavy duty vehicles is the braking system. The braking system can be divided into EBS brakes, exhaust brake and retarder, where the latter is of interest in the present Master's Thesis. This thesis presents an investigation whether it is possible to substitute today's concept, i.e. controlling the air pressure to the retarder using a proportional-valve, with two so-called on/o®-valves and a pressure sensor, which will reduce expenses and contingently hysteresis phenomena seen in the current system. A non-linear model of the Electronic Control Unit (ECU) electrical drives, and the electrical, magnetic, mechanical, and pneumatic parts of the valves, is designed. A Proportional-Integral-Derivative (PID)-controller is designed based on the derived model. Two di®erent pulsing schemes have been investigated. However, just one of the approaches together with the results from the other one is presented in this thesis. In order to improve the control performance non-linear control and prediction methods are used so that required time response and robustness is achieved. Finally the modelled current and pressure are validated against the measured data, and a verification of the controller is done on the prototypes.

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Chun, Darren M. K. (Darren Masayasu Kekoa). "Investigation into the cause of pneumatic actuator failure on the HypoSurface." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40412.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.
Includes bibliographical references (leaf 11).
An investigation into the failure of pneumatic actuators on the HypoSurface was conducted to provide information on the current HypoSurface prototype. Using a systematic approach throughout testing, piston components were found to have been subjected to fatigue-failure, causing pressure leaks from the piston. Through further analysis, the increase in wear on the piston gaskets was caused by exceeding the recommended loads during operation of the HypoSurface with its skin. Furthermore, vibrations from piston actuation may be the cause of loose electrical connections in the control panel, resulting in voltage problems in the solenoids.
by Darren M.K. Chun.
S.B.

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Gjone, Kristoffer. "Robustness Tests and Analysis of Control Strategies on an Electro-pneumatic Actuator." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8719.

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In this thesis a Sliding Mode Controller (SMC) is designed for an electro-pneumatic clutch actuator controlled by two on/off valves with PWM. The areas of application of the clutch actuator is in Automated Manual Transmission (AMT) and Clutch-by-wire (CBW) systems in heavy-duty trucks. As with most automated systems in the automation industry safety is the main priority, and in a cybernetic point of view this means that robustness of the control systems is very important. Sliding Mode Controllers are known for their excellent robustness properties and the focus of this thesis is to validate these properties for this particular application. The robustness properties of the SMC also indicates that a simple design model is adequate and since the existing mathematical models for this system are quite complex some simplifications are introduced. The controller design is performed in two phases. First an ideal SMC is designed, but since this introduces discontinuities in the control law any practical implementation would give heavy chattering at the output from the controller. Therefore a continuous linear approximation to the discontinuity is introduced. This controller is known as a boundary layer controller and it will reduce the control chattering to an acceptable level. The ideal controller is proven to be asymptotically stable, while for the boundary layer controller ultimate boundedness is achieved and a linearisation is performed for the case of a constant reference and this analysis shows that the origin of the linearised system is a stable focus. This indicates that the boundary layer controller might also be asymptotically stable. Since only a positionmeasurement is available to the control system the rest of the system states must be estimated. Velocity and acceleration are simply estimated as the first and second order filtered derivatives of the position measurement. The pressure is estimated based on the equation of motion for the clutch actuator. Through computer simulations and experimental testing the SMC has shown satisfying tracking performance and very good robustness with respect to parameter variations. Comparisons with a PD and a Backstepping controller shows that the performance of the SMC is superior to the PD controller and absolutely comparable to the Backstepping controller, though they have different strengths and weaknesses and therefore yield rather different results.

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31

Hall, Kara Lynn. "Dynamic Control for a Pneumatic Muscle Actuator to Achieve Isokinetic Muscle Strengthening." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1307113453.

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32

Håkansson, Klas, and Mikael Johansson. "Modeling and Control of an Electro-Pneumatic Actuator System Using On/Off Valves." Thesis, Linköping University, Department of Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8754.

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To control the exhaust gas recirculation (EGR) and the exhaust brake, the position of a butterfly valve connected to a piston inside a pneumatic cylinder is controlled by altering the pressure inside the cylinder. This thesis evaluates the possibility to do this with pulse width modulation (PWM) controlled On/Off valves. The whole electro-pneumatic actuator system is built out of two On/Off valves and a cylinder.

A mathematical model of the system is constructed. The complete system model on state space form consists of nine states and is nonlinear. The model captures the dynamics of the system. The statics of the system is not captured as accurately. The model is still good enough to be used as aid when developing control strategies, since position feedback is available.

Automatic control strategies for the system are first developed and tested in simulation. The first approach is PID control. Because of the nonlinear properties of the system the results from a PID with a constant proportional part is unsatisfactory. To cope with the nonlinearities, a fuzzy controller is constructed; the results prove somewhat better, but not as good as expected due to implementation difficulties.

In a test bench the system is controlled by a P controller with feedforward from position. The feedforward strongly reduces the nonlinear behavior of the system. With this implementation the results that were hoped for with the fuzzy controller are reached.

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Volf, Marek. "Přesné polohování pneumatických pohonů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229364.

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Thesis starts with brief overview of the present role of pneumatic actuators. Further research is carried out in modelling and control of pneumatic actuators. A basic overview of thermodynamic laws is presented. These laws are used to assemble a mathematical model of the pneumatic drive. Subsequently the identification of model parameters is shown. A controller is propřed using fuzzy PID algorithms. Results are compared with the conventional PID controller.

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Jeník, Jan. "Optimalizace konstrukce zvedače dutinky spřádacího stroje." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230327.

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The first part of this thesis describes the current technologies of mechanical spin-ning. This is a ring, rotor and air-jet spinning. The product of spinning machines is yarn, the basic material for production textile. The next section describes in detail the current state of the node manipulator lifter tube on spinning machine TORNADO J20, by concern RIETER. It describes the structure, kinematics, duty cycle and requirements for the manipulator. The following optimization options which are described more options for solutions of individual functions of the manipulator, on the end is selected by multi-criteria analysis. The best solution that is elaborate in the next section. The author has created 3-D model optimized lifter tube. Positioning mechanism maintains the current kinematics, it is very similar. But gripper was designed as a passive, thus reduce the load positioning mechanism. Optimization was performed primarily to reduce overall production costs and to reduce weight manipulator. The conclusion is a comparison of current and new solutions. There are also eco-nomic recovery to.

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Vlasák, František. "Konstrukce koncového testovacího zařízení elektromagnetu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254347.

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Master thesis describes a single-purpose machine design, that is used for testing a basic features of proportional solenoid. The design is created in cooperation with company NUVIA a.s. and contains mechanical solution that is processed in respect with ergonomic requirements, safety and overall costs. Machine concept is affected by customer requirements, whose name, as well as real parameters of the product will not be published, because of non-disclosure agreement.

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36

Isaksen, Trond Willi. "Discrete-Time Backstepping Design Applied to Position Tracking Control of an Electro-Pneumatic Clutch Actuator." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8743.

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This thesis investigates different methods of backstepping controller design for an electro-pneumatic clutch actuator used in heavy duty trucks. The first part of the thesis is a literature study, where the subject is control of nonlinear-sampled data systems in general. Sampled-data systems contain a continuous-time plant and a digitally implemented controller, which in general make them harder to analyze and control than systems that operate purely in the continuous-time or discrete-time domain. The available theory of nonlinear sampled-data control systems is scarce, but three different methods are described in this thesis; emulation design, direct discrete-time design, and sampled-data design. The electro-pneumatic clutch actuator is controlled using a continuous-time backstepping controller implemented digitally. This is essentially the procedure of emulation design and is the common, if not only, method used in practical engineering tasks so far. However, redesign of the continuous-time controller using the direct discrete-time method shows great potential of improving performance and robustness of sampled-data systems. Direct discrete-time design is based on an approximate discrete-time model of the plant, giving the controller a structure that accounts for the sampling of the hybrid system. Potentially, one can utilize slower sampling in the system by implementing a discrete-time controller into the digial computer instead of a continuous-time one. Examples and case studies that prove the improvement one can achieve by chosing the direct discrete-time design is included in the first part of the thesis. Both a third- and fifth-order model of the electro-pneumatic clutch actuator are presented, and used as a basis for continuous- and discrete-time state-feedback backstepping controllers. These controllers are simulated with different sampling intervals to show their performance under different circumstances. The continuous-time controllers prove good reference trajectory tracking of the pure continuous-time system, while the performance of the sampled-data systems descends as higher sampling intervals are used. And, as opposed to the mentioned examples and case studies, the controller designed when taking the sampling into account shows no sign to outperform the controller that was designed without considering the sampling, at least not for the relative fast sampling the clutch actuator operates with.

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Mehmood, Adeel. "Modeling, simulation and robust control of an electro-pneumatic actuator for a variable geometry turbocharger." Phd thesis, Université de Technologie de Belfort-Montbeliard, 2012. http://tel.archives-ouvertes.fr/tel-00827445.

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The choice of technology for automotive actuators is driven by the need of high power to size ratio. In general, electro-pneumatic actuators are preferred for application around the engine as they are compact, powerful and require simple controlling devices. Specially, Variable Geometry Turbochargers (VGTs) are almost always controlled with electro-pneumatic actuators. This is a challenging application because the VGT is an important part of the engine air path and the latter is responsible for intake and exhaust air quality and exhaust emissions control. With government regulations on vehicle pollutant emissions getting stringent by the year, VGT control requirements have also increased. These regulations and requirements can only be fulfilled with precise dynamic control of the VGT through its actuator. The demands on actuator control include robustness against uncertainty in operating conditions, fast and smooth positioning without vibration, limited number of measurements. Added constraints such as nonlinear dynamic behavior of the actuator, friction and varying aerodynamic forces in the VGT render classical control methods ineffective. These are the main problems that form the core of this thesis.In this work, we have addressed the above mentioned problems, using model based control complemented with robust control methods to overcome operational uncertainties and parametric variations. In the first step, a detailed physical model of an electro-pneumatic actuator has been developed; taking into account the nonlinear characteristics originating from air compressibility and friction. Means to compensate for aerodynamic force have been studied and implemented in the next step. These include model parametric adaptation and one dimensional CFD (Computational Fluid Dynamics) modeling. The complete model has been experimentally validated and a sensitivity analysis has been conducted to identify the parameters which have the greatest impact upon the actuator's behavior. The detailed simulation model has then been simplified to make it suitable for control purposes while keeping its essential behavioral characteristics (i.e. transients and dynamics). Next, robust controllers have been developed around the model for the control objective of accurate actuator positioning in presence of operational uncertainty. An important constraint in commercial actuators is that they provide output feedback only, as they are only equipped with low-cost position sensors. This hurdle has been overcome by introducing observers in the control loop, which estimate other system states from the output feedback. The estimation and control algorithms have been validated in simulation and experimentally on diesel engine test benches.

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Irshaidat, M. M. "Design and implementation of a novel lightweight soft upper limb exoskeleton using pneumatic actuator muscles." Thesis, University of Salford, 2018. http://usir.salford.ac.uk/48758/.

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Stroke is the leading cause of disability and weakness in the UK and around the world. Thus, stroke patients require an extensive rehabilitation therapy to regain some of the weaknesses. Many rehabilitation robotic devices have been designed and developed to assist the stroke patients to perform their activities of daily living and to perform repetitive movements. However, these devices remain unmanageable to use by the patients alone not only because they are cumbersome to use but also due to their weights, rigid, fix and non-portable characteristics. Thus there is a need to invent a novel exoskeleton soft arm that has a lightweight and a high power to rehab the elbow joint with lower cost and without the need to therapists. Here for elbow joint rehabilitation, we investigate and propose a novel exoskeleton soft robotic arm, which is wearable, lightweight and portable so that it would allow patients to perform repetitive motion therapy more often with a greater intensity in their homes and relevant to their Activities of Daily Living (ADL). The proposed arm consists of various bending pneumatic muscle actuators (pMA), where traditional pMA are not suitable. Testing on various pMA (traditional and bending) revealed its behaviour and the relationship between pressure, length, force, and bending angle in different setups such as isotonic and isometric. Experiments are done to analyse its non-linear behaviour, moreover, geometrical and numerical models are compared to the experimental results to validate the results. A developed control approach to control the soft arm is implemented to validate the design. Model reference adaptive control (MRAC) to control the arm using (Proportional, Integral, and Derivative) PID controller as an input for MRAC. Neural Network (NN) is also used in MRAC to improve the performance of MRAC.

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Serres, Jennifer L. "Dynamic Characterization of a Pneumatic Muscle Actuator and Its Application to a Resistive Training Device." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1227233038.

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40

Le, Minh-Quyen. "Development of bilateral control for pneumatic actuated teleoperation system." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00717743.

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The aim of this thesis is to investigate the development and control of electro-pneumatic actuators in a haptic teleoperation system. For controlling the mass flow rate of such actuators, two types of valve technology are sudied, i.e. solenoid (on/off) valve and proportional servovalve. The servovalves have found widespread applications in which high accuracy of force/position control are needed. They are however typically expensive due to the requirements of high-precision manufacturing. Therefore, the low-cost solenoid valves can be an alternative to the servovalves for achieving acceptable-performance pneumatic control. Generally, the highly nonlinear of the pneumatic actuator is heightened when it uses on/off solenoid valves instead of servovalves. In this case, precise control is challenging due to the discrete-input nature of the system. Our first objective is to demonstrate that it is possible to design an acceptable performance teleoperation system using master-slave robots that have pneumatic actuators equipped with only inexpensive on/off solenoid valves. To control efficiently the switching valves, several control approaches have been proposed, namely pulse width modulation (PWM), hybrid algorithm, and sliding mode control. A hybrid control theory, which includes more switching control modes, than PWM, allows to reduce the chattering problem and improve the energy consumption of the valves. Another strategy (i.e. a sliding mode control), which does not depend on the pneumatic model, is proposed. This control stratgy allows to perform not only the transparent analysis but also the stability analysis. In order to improve the dynamic performance and reduce the chattering problem in solenoid valve actuated pneumatic teleoperation systems, a five-mode sliding control scheme has been used, which can be considered as an extension of the three-mode sliding controller. Our study demonstrates that by increasing the number of possible control actions for the valves, we can reduce the valves' switching activities, hence improving the valve's life times at no cost to teleoperation transparency. The second objective of the thesis involves in implementing the proportional servovalves on the pneumatic teleoperation system. A comparison related to the teleoperation performance between an on/off valve and a servovalve is carried out. In experiments, it is observed that with the bilateral teleoperation architecture employing solenoid valves or servovalves, satisfactory force and position tracking between the master and the slave is obtained. In bilateral teleoperation control, force sensors are often omitted to save cost and to lessen weight and volume. Therefore, another aspect of our work consists in using observers for an estimation of operator and environment forces. Experimental results show that acceptable teleoperation transparency based on a simple Nicosia observer and a tangent linear control approach can be achieved.

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Rydén, Gustav, and Fredrik Anarp. "Beräkningsmodell för slagtider av pneumatiska manöverdon : En experimentell och teoretisk studie av beteendet för pneumatiska cylindrar samt manöverdon." Thesis, Linköpings universitet, Fluida och mekatroniska system, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-166356.

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Denna rapport redogör framtagningen av en beräkningsmodell för slagtider av pneumatiska cylindrar och manöverdon. Slagtiderna för ett manöverdon kan bestämmas genom experimentella tester. För att underlätta och minska tiden som krävs i samband med testerna skapas en beräkningsmodell som presenterar teoretiska värden för slagtiderna. Denna beräkningsmodell stämmer kvalitativt överens med de experimentella tester som också genomförs i detta arbete. Testerna genomförs först på en enkel pneumatisk cylinder vilket bidrar till kunskaper om slagkarakteristik och slagtider. Denna kunskap är till hjälp för utveckling av beräkningsmodellen. Under testerna mäts bland annat slagtid, kammartryck och kolvens förflyttning vid en mängd olika driftförhållanden. Testerna visar att en av de mest kritiska parametrarna för beräkningsmodellen är C-värdet, en parameter som beskriver flödeskarakteristiken för pneumatiska komponenter. För att få beräkningsmodellen att fungera väl behöver ett så korrekt C-värde som möjligt användas. Beräkningsmetodiken består i stora drag av samband för fyllning och tömning av pneumatiska volymer samt tryckförändringar i cylinderkamrarna vid kompression och expansion. Med en kombination av dessa ekvationer är det möjligt att beräkna slagtiden. Eftersom beräkningsmodellen vill hållas relativt enkel görs ett antal antaganden om systemets parametrar. Dessa antaganden utvärderas efter deras påverkan på slagtiden. Validering mot experimentella resultat visar att beräkningsmodellen generellt fungerar bättre vid höga matningstryck och kritiska flöden. När matningstrycket är lågt och underkritiska flöden erhålls påverkas slagtiden av många fler parametrar, vilket gör att beräkningsmodellen får något sämre precision. Detta resultat är inte helt oväntat eftersom sambandet för kritiskt flöde är relativt enkelt.
This thesis work describes the development of a calculation model for stroke times of pneumatic cylinders and actuators. The stroke time of an actuator can be determined by experimental tests. To facilitate and reduce the time required in connection with the tests, a calculation model is created which presents theoretical values of the stroke time. This calculation model is qualitatively consistent with the experimental tests carried out in this work. The tests are first carried out on a simple pneumatic cylinder, which contributes to knowledge of stroke characteristics and stroke times. This knowledge is helpful for the development of the calculation model. During the tests the stroke time, chamber pressure and piston movement are measured in a variety of operating conditions. The tests show that one of the most critical parameters for the calculation model is the C value, a parameter that describes the flow characteristics of pneumatic components. To make the calculation model reliable, a reasonable C value need to be used. The calculation method consists largely of equations for filling and emptying of pneumatic volumes as well as pressure changes in the cylinder chambers during compression and expansion. With a combination of these equations it is possible to calculate the stroke time. Since the calculation model wants to be kept relatively simple, several assumptions are made about parameters in the system. These assumptions are evaluated according to their potential and impact on the stroke time. Validation experiments show that the calculation model generally works better at high supply pressures and critical flows. When the supply pressure is low and subcritical flow are obtained, the stroke time is affected by many more parameters, which lower the precision of the calculation model. This result is not entirely unexpected since the critical flow equations are relatively simple.

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Höijertz, Erik. "Supercoiled Actuators with Liquid Metal Joule Heating : novel miniaturized actuators for pneumatic control of reconfigurable wearables." Thesis, Uppsala universitet, Mikrosystemteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-426008.

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Garments serve a number of purposes, from protection and physiological comfort to social and cultural expressions. With the recent developments of active textiles, sensors and actuators with shapes and sizes similar to textiles, the real multifunctional garments have been realized. The functions of such garments can be regulating heat by changing the spacing between the strands of yarn, giving massage or assisting lifting movement by expanding and contracting one or more actuators. This project is a part of a main project targeting on reconfigurable hybrid wearables. The main started from studying possible actuators that could have textile-like properties, where pneumatic actuators were chosen. A model of different forces, strains and braiding angles of a pneumatic actuator sometimes called a McKibben muscle was made. It should be noted that such garments with pneumatic actuators to be functional and applicable each segment needed an external pump. For local actuation, miniaturized servo valves were needed. Hence, study on super coiled actuators (SCAs) was initiated to investigate their potential of controlling the valves for constricting the flow when needed. In this project different SCAs were developed and their performances were recorded. To assist with heating of the SCAs Galinstan and Gallium were used as electric resistors to provide for Joule heating. A contraction of over 19% and an efficiency of 0.29% were achieved but could most likely be improved by optimizing the fabrication and testing process.

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Papoutsidakis, Michail G. "Modern methods for position control of systems : real-world and simulated application to a time variant pneumatic actuator." Thesis, University of the West of England, Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501091.

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The Ph.D. programme arose naturally from the fundamental questions remaining after completing MPhil research at UWR in a very similar subject area. which was in achieving effective proportional position control of a linear pneumatic actuator. There are many challenging reasons for using pneumatic systems for control in certain important potential application areas, i.e., their numerous and multiple applications in modern industry due to their extensive beneficial characteristics. The still-unsolved problem of robust long-term proportional control of pneumatic actuators keeps the continuous research interest of engineers high. It is believed that when the operation time increases, so does the temperature inside the cylinder body.Any increase in temperature affects the system performance. For example, one effect is that the piston rubber expands and the contact area becomes greater; hence the frictional forces are affected. The rubber seal, which is between the piston and the cylinder body, also deforms according to air pressure increase. These long-term effects were the major cause of the problems that existed during all of the author's MPhil experimentation, using any kind of control method; the result was that frequent retuning of the controller could not be avoided.

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Shaheen, Robert. "Design and Material Characterization of a Hyperelastic Tubular Soft Composite." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36117.

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Research within the field of human motion assistive device development, with the purpose of reducing the metabolic cost of daily activities, is seeing the benefits of the exclusive use of passive actuators to store and release energy during the gait cycle. Designs of novel exoskeletons at the University of Ottawa implement the Pneumatic Artificial Muscle (PAM) as the primary method of nonlinear, passive actuation. The PAM is proven as a superior actuator for these devices when compared to the linear mechanical springs used by other researchers. There are, however, challenges regarding PAM pressure loss and the limitation of PAM elongation that have been identified. This thesis aims to develop a hyperelastic tubular soft composite that replicates the distinctive mechanical behaviour of the PAM without the need for internal pressurization. The final soft composite solution was achieved by impregnating a prefabricated polyethylene terephthalate braided sleeve, held at a high initial fibre angle, with a silicone prepolymer. A comprehensive experimental evaluation was performed on numerous prototypes for a variety of customizable design parameters including: initial fibre angle, silicone stiffness, and braided sleeve style. Moreover, two separate analytical models were formulated based on incompressible finite elasticity theory using either a structural model of Holzapfel’s type, or a phenomenological model of Fung’s type. Both models were in good agreement with the experimental data that were collected through a modified extension-inflation test. This research has successfully developed, tested, and validated an innovative soft composite that can achieve specific mechanical properties, such as contraction distance and nonlinear stiffness, for optimal use in human motion assistive devices.

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Chen, Yi. "Experimental characterization and modelling of a servo-pneumatic system for a knee loading apparatus." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8565/.

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The new knee test rig developed in University of Bologna used pneumatic cylinder as actuator system. Specific characterization and modelling about the pneumatic cylinder and the related devices are needed in better controlling the test rig. In this thesis, an experimental environment for the related device is set up with data acquisition system using Real-time Windows Target, Simulink, MatLab. Based on the experimental data, a fitted model for the pneumatic cylinder friction is found.

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Kopečný, Lukáš. "McKibbenův pneumatický sval - modelování a použití v hmatovém rozhraní." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233458.

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This work describes exceptional properties of McKibben pneumatical muscle and introduces its state-of-the-art model. The mathematical model is extended especially in a field of a thermodymical behavior. A new model applies a method used for describing of a thermodynamical behavior of pneumatic cylinders until now. This method is significantly upgraded to fit a muscle behavior, particularly by considering a heat generated by a muscle internal natural friction. The model is than verified and discussed with a real system. The haptic part introduces a development and design of a haptic glove interface for the use in robotics, especially in telepresence, or in VR. The force and touch feedback is provided by Pneumatic Muscles controlled by an open loop algorithm using the introduced mathematical model. The design is light and compact.

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Hrivňák, Ján. "Analýza dynamických vlastností pneumatického aktuátoru." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230570.

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This thesis deas with dynamic analysis of pneumatic actuator which is used as regulation mechanis of turbochargers with Variable Nozzle Turbine (VNT) technology. The first part of work is focused on experimental modeling which goal is obtaining Frequency Response Function on specify frequency range by Frequency Response Function Analysis – FRFA. Dominant vibrations of pneumatic actuator active parts is expected on this specify frequency range. Results of experimental modeling will be used for gaining input parameters for numerical computation as well. The second part deal with Pre-Stressed Modal Analysis and subsequently Harmonic analysis. Obtained results with numerical and experimental analysis will be compared. This part of diploma thesis is solved in programmatic environment ANSYS Workbench.

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Wu, Xiaosong. "A reconfigurable tactile display based on polymer MEMS technology." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22623.

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This research focuses on the development of polymer microfabrication technologies for the realization of two major components of a pneumatic tactile display: a microactuator array and a complementary microvalve (control) array. The concept, fabrication, and characterization of a kinematically-stabilized polymeric microbubble actuator (¡°endoskeletal microbubble actuator¡±) were presented. A systematic design and modeling procedure was carried out to generate an optimized geometry of the corrugated diaphragm to satisfy membrane deflection, force, and stability requirements set forth by the tactile display goals. A refreshable Braille cell as a tactile display prototype has been developed based on a 2x3 endoskeletal microbubble array and an array of commercial valves. The prototype can provide both a static display (which meets the displacement and force requirement of a Braille display) and vibratory tactile sensations. Along with the above capabilities, the device was designed to meet the criteria of lightness and compactness to permit portable operation. The design is scalable with respect to the number of tactile actuators while still being simple to fabricate. In order to further reduce the size and cost of the tactile display, a microvalve array can be integrated into the tactile display system to control the pneumatic fluid that actuates the microbubble actuator. A piezoelectrically-driven and hydraulically-amplified polymer microvalve has been designed, fabricated, and tested. An incompressible elastomer was used as a solid hydraulic medium to convert the small axial displacement of a piezoelectric actuator into a large valve head stroke while maintaining a large blocking force. The function of the microvalve as an on-off switch for a pneumatic microbubble tactile actuator was demonstrated. To further reduce the cost of the microvalve, a laterally-stacked multilayer PZT actuator has been fabricated using diced PZT multilayer, high aspect ratio SU-8 photolithography, and molding of electrically conductive polymer composite electrodes.

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Petrov, Denis [Verfasser], Wolfgang [Akademischer Betreuer] Benecke, and Walter [Akademischer Betreuer] Lang. "Development of the technological process for the production of the electrostatic curved beam actuator for pneumatic microvalves / Denis Petrov. Gutachter: Wolfgang Benecke ; Walter Lang. Betreuer: Wolfgang Benecke." Bremen : Staats- und Universitätsbibliothek Bremen, 2012. http://d-nb.info/1071993917/34.

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Mikol, Collin Everett. "Design, Modeling, and Experimental Testing of a Variable Stiffness Structure for Shape Morphing." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523454926569658.

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Dissertations / Theses on the topic 'Pneumatic actuation'

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