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Kwon, Hyun-Jung, Hyun-Joon Chung, and Yujiang Xiang. "Human Gait Prediction with a High DOF Upper Body: A Multi-Objective Optimization of Discomfort and Energy Cost." International Journal of Humanoid Robotics 14, no. 01 (March 2017): 1650025. http://dx.doi.org/10.1142/s0219843616500250.
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To predict the 3D walking pattern of a human, a detailed upper body model that includes the spine, shoulders, and neck must be made, which is challenging because of the coupling relations of degrees of freedom (DOF) in these body sections. The objective of this study was to develop a discomfort function for including a high DOF upper body model during walking. A multi-objective optimization (MOO) method was formulated by minimizing dynamic effort (DE) and the discomfort function simultaneously. The discomfort function is defined as the sum of the squares of deviation of joint angles from their neutral angle positions. The neutral angle position is defined as a relaxed human posture without actively applied external forces. The DE is the sum of the joint torque squared. To illustrate the capability of including a high DOF upper body, backward walking is used as an example. By minimizing both DE and the discomfort function, a 3D whole-body model with a high DOF upper body for walking was simulated successfully. The proposed MOO is a promising human performance measure to predict human motion using a high DOF upper body with full range of motion. This has been demonstrated by simulating backward walking, lifting, and ingress motions.
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WIJAYA, RYAN SATRIA, KEVIN ILHAM APRIANDY, M. RIZQI HASAN AL BANNA, RADEN SANGGAR DEWANTO, and DADET PRAMADIHANTO. "Analisis Kinematika dan Pola Gerakan Berjalan pada Robot Bipedal Humanoid T-FLoW 3.0." ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika 10, no. 1 (January 14, 2022): 31. http://dx.doi.org/10.26760/elkomika.v10i1.31.
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ABSTRAKRobot humanoid merupakan robot menyerupai manusia dengan tingkat kompleksitas yang tinggi dan fungsi yang serbaguna. Pada penelitian ini dilakukan analisis model kinematika gerak pada robot bipedal humanoid TFLoW 3.0, serta menganalisis pola gerakan berjalannya. Pola pergerakan yang diimplementasikan pada robot bipedal TFLoW 3.0 merupakan hasil pendekatan dari teori cara berjalan manusia dengan menggunakan enam gerakan dasar manusia saat berjalan. Kemudian menganalisis model gerakan robot menggunakan kinematika terbalik dengan solusi geometri. Tujuan dari model kinematika terbalik adalah untuk mengubah data input berupa posisi kartesian menjadi nilai sudut untuk setiap parameter joint pada masing-masing Degrees of Freedom (DoF). Lalu dilakukan analisis model mekanik robot saat berjalan yang terbagi atas fase tegak dan fase berayun yang bertujuan untuk mengetahui hasil pengujian.Kata kunci: robot humanoid, gaya berjalan, kinematika, TFLoW, DoF. ABSTRACTHumanoid robots are human-like robots with a high level of complexity and versatile functions. In this study, kinematics analyze on TFLoW 3.0 humanoid bipedal robot is carried out, as well as analyzing the pattern of its walking movement. The implemented movement of TFLoW 3.0 bipedal robot is the result of an approach from human walk using six basic human movements when walking. the robot movement model is analyzed by inverse kinematics with geometric solutions. Invers kinematics model is to transform the input data in the form of a Cartesian position into an angle value for each joint parameter in each Degrees of Freedom (DoF). Then an analysis of the robot's mechanical model when walking is carried out which is divided into a stance phase and a swinging phase which aims to determine the test results.Keywords: humanoid robot, gait, kinematics, TFLoW, DoF.
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Abdulrahman, Alaa, Kamran Iqbal, and Gannon White. "Improving Inverse Dynamics Accuracy in a Planar Walking Model Based on Stable Reference Point." Journal of Robotics 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/245896.
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Physiologically and biomechanically, the human body represents a complicated system with an abundance of degrees of freedom (DOF). When developing mathematical representations of the body, a researcher has to decide on how many of those DOF to include in the model. Though accuracy can be enhanced at the cost of complexity by including more DOF, their necessity must be rigorously examined. In this study a planar seven-segment human body walking model with single DOF joints was developed. A reference point was added to the model to track the body’s global position while moving. Due to the kinematic instability of the pelvis, the top of the head was selected as the reference point, which also assimilates the vestibular sensor position. Inverse dynamics methods were used to formulate and solve the equations of motion based on Newton-Euler formulae. The torques and ground reaction forces generated by the planar model during a regular gait cycle were compared with similar results from a more complex three-dimensional OpenSim model with muscles, which resulted in correlation errors in the range of 0.9–0.98. The close comparison between the two torque outputs supports the use of planar models in gait studies.
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Roberts, Dustyn, Joseph Quacinella, and Joo H. Kim. "Energy expenditure of a biped walking robot: instantaneous and degree-of-freedom-based instrumentation with human gait implications." Robotica 35, no. 5 (January 14, 2016): 1054–71. http://dx.doi.org/10.1017/s0263574715000983.
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SUMMARYEnergy expenditure (EE) is an important criterion for design and control of biped walking robots. However, the cause-effect analyses enabled by total EE, which is lumped over a time duration and all system degrees-of-freedom (DOFs), are limited. In this study, robotic gait energetics is evaluated through a DOF-based instrumentation system designed for instantaneous evaluation of bidirectional current and applied voltage at each joint actuator. The instrumentation system includes a dual-module arrangement of buffers and attenuators, and accommodates and synchronizes the voltage and current measurements from multiple actuators. For illustrative purposes, this system is implemented at each DC servomotor in a biped robot, DARwIn-OP, to analyze the electrical EE rates for walking at various speeds. In addition, a DOF-based model of instantaneous human EE rate is employed to enable quantitative characterization of robotic walking EE relative to that of humans. The robot's instantaneous lower-body EE rates are consistent with its periodic walking cycle, and their relative trends between single and double support phases are analogous to those of humans. The robotic cost of transport (COT) curve as a function of normalized speed is also consistent with the human COT in terms of its convexity. Conversely, the contrasting distributions of EE throughout the robot and human DOFs and the robotic COT curve's considerably larger magnitudes, smaller speed ranges, and higher sensitivity to speed illustrate the energetic consequences of stable but inefficient static walking in the biped robot relative to the more efficient dynamic walking of humans. These energetic characteristics enable the identification of the joints and gait cycle phases associated with inefficiency in biped robotic gait, and reflect the noticeable differences in the system parameters (rigid and flat versus segmented feet) and gait control strategies (bent versus straight knees, instants of peak ankle actuator torques, static versus dynamic balance stability). The proposed general instrumentation provides a quantitative approach to benchmarking human gait as well as general guidelines for the development of energy-efficient walking robots.
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Rosales-Luengas, Yukio, Karina I. Espinosa-Espejel, Ricardo Lopéz-Gutiérrez, Sergio Salazar, and Rogelio Lozano. "Lower Limb Exoskeleton for Rehabilitation with Flexible Joints and Movement Routines Commanded by Electromyography and Baropodometry Sensors." Sensors 23, no. 11 (June 1, 2023): 5252. http://dx.doi.org/10.3390/s23115252.
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This paper presents the development of an instrumented exoskeleton with baropodometry, electromyography, and torque sensors. The six degrees of freedom (Dof) exoskeleton has a human intention detection system based on a classifier of electromyographic signals coming from four sensors placed in the muscles of the lower extremity together with baropodometric signals from four resistive load sensors placed at the front and rear parts of both feet. In addition, the exoskeleton is instrumented with four flexible actuators coupled with torque sensors. The main objective of the paper was the development of a lower limb therapy exoskeleton, articulated at hip and knees to allow the performance of three types of motion depending on the detected user’s intention: sitting to standing, standing to sitting, and standing to walking. In addition, the paper presents the development of a dynamical model and the implementation of a feedback control in the exoskeleton.
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Geonea, Ionuț Daniel, Alexandru Margine, Nicolae Dumitru, and Cristian Copiluși. "Design and Simulation of a Mechanism for Human Leg Motion Assistance." Advanced Materials Research 1036 (October 2014): 811–16. http://dx.doi.org/10.4028/www.scientific.net/amr.1036.811.
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Legs are the mostimportant elements for accomplishing human physical work includingtransportation or displacement. In this paper, a new mechanism for human legmotion assistance has been proposed for rehabilitation purposes. The structureof human leg and its motions have been used as inspiration for design purposes.For a simple control algorithm, the proposed mechanism for the legs mustgenerate an ovoid path of the foot, by uniform rotating of actuating crank. Themechanism must generate an approximately linear trajectory of foot duringpropulsion. The resulting linkage is a single degree-of-freedom (DOF)mechanism, which exemplifies the shape and movement of a human leg. Theactuator of the mechanism is located in the upper portion of the linkagesimilar to it in a human leg. The mechanism is simulated and tested to verifythe proposed synthesis. A 3D model of the proposed system has been elaboratedin Solid Works®, booth for design and simulation purposes. Simulation resultsshow that the proposed mechanism performs movements similar to those of a humanleg. Maple and Adams software packages are used to simulate and validate the usabilityof the mechanism. The proposed mechanism demonstrates that a one DOF closedloop mechanical linkage can be designed to the shape and movement of the bipedhuman walking apparatus. The proposed mechanism is suitable for the fabricationof legged robots. Proportions of the linkage are estimated utilizinganthropometric measures of the human leg.
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Yoneda, Kan, Yusuke Ota, Fumitoshi Ito, and Shigeo Hirose. "Quadruped Walking Robot with Reduced Degrees of Freedom." Journal of Robotics and Mechatronics 13, no. 2 (April 20, 2001): 190–97. http://dx.doi.org/10.20965/jrm.2001.p0190.
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We advocate the effectiveness of a walking robot to have a structure with a reduced DOF, not based on a model of real animals, to make the robot lightweight and practical, and discuss a technique for reducing the active degrees of freedom (DOF) of a quadruped walking robot as an example for realizing such objectives. If functions required of a quadruped walking robot are properly organized and the required active DOF is examined, 4 active DOF make it possible to select an arbitrary position on uneven terrain and to move in all directions. We describe a mechanism with 4 active DOF and 2 passive DOF as an example of concrete configurations for quadruped walking robots with 4 active DOF. A robot with a reduced active DOF, namely with 3 active DOF and 2 passive DOF, has a capability to reach an arbitrary position at an arbitrary angle on uneven terrain. An actual mechanical model was manufactured as an experimental model, and a walking experiment was conducted. The mechanical model turned out to be about one-4th in weight compared to a conventional biomimetic model of the same size. Based on the walking experiment, it was confirmed that this mechanical model can carry a load up to 4 times its own weight.
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Rusu, Lucian, Mirela Toth-Taşcău, and Cristian Toader-Pasti. "Virtual Geometric Model of the Human Lower Limb." Key Engineering Materials 601 (March 2014): 193–96. http://dx.doi.org/10.4028/www.scientific.net/kem.601.193.
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The aim of this paper is to develop and validate the mathematical model of the human lower limb based on Denavit-Hartenberg (D-H) robotics convention. The proposed geometric model has 7 degrees of freedom (DOF) (3 DOF in hip joint, 2 DOF in knee joint, and 2 DOF in ankle joint). The fixed reference system was placed in the weight centre of the human body. The input data for the model are the angle variations and anthropometric parameters of the lower limb. The angle variations can be defined or imported from a gait analysis system. The anthropometric parameters were introduced from the literature. The model can be adapted to both left and right lower limb. The geometric model was solved in MATLAB environment. The model validation was individually realized taking into account the normal range of motion (ROM) of each joint.
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CERDA, GUSTAVO MEDRANO, HOUMAN DALLALI, and MARTIN BROWN. "CONTROL OF A COMPLIANT HUMANOID ROBOT IN DOUBLE SUPPORT PHASE: A GEOMETRIC APPROACH." International Journal of Humanoid Robotics 09, no. 01 (March 2012): 1250004. http://dx.doi.org/10.1142/s0219843612500041.
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Enhancing energy efficiency of bipedal walking is an important research problem that has been approached by design of recently developed compliant bipedal robots such as CoMan. While compliance leads to energy efficiency, it also complicates the walking control system due to further under-actuated degrees of freedom (DoF) associated with the compliant actuators. This problem becomes more challenging as the constrained motion of the robot in double support is considered. In this paper this problem is approached from a multi-variable geometric control aspect to systematically account for the compliant actuators dynamics and constrained motion of the robot in double support phase using a detailed electro-mechanical model of CoMan. It is shown that the formulation of constraint subspace is non-trivial in the case of non-rigid robots. A step-wise numerical algorithm is provided and the effectiveness of the proposed method is illustrated via simulation, using a ten DoF model of CoMan.
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Sudharsan, Jayabalan, and L. Karunamoorthy. "Derivation of Forward and Inverse Kinematics of 8 - Degrees of Freedom Based Bio-Inspired Humanoid Robotic Arm." Advanced Materials Research 984-985 (July 2014): 1245–52. http://dx.doi.org/10.4028/www.scientific.net/amr.984-985.1245.
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Designing a humanoid robot is a complex issue and the exact resemblance of human arm movements has not been achieved in many of the previously developed robots. This paper is going to be much focused on the design of a humanoid robot arm which has a unique approach which has never been developed earlier. Even though all the robots that have been developed using 6-Degrees of Freedom (DOF) and 7-DOF can reach any point in the space, some of the orientation cannot be reached by the end effector plane effectively. So an 8-DOF freedom based robotic arm has been specially designed and developed to resemble the exact movements of the human being. This robot has 3-DOF for shoulder joint, 2-DOF for the elbow joint, and 3-DOF for the wrist with fingers as the end effector. Almost all the robots have only 1-DOF to the elbow joint but here 2-DOF has been proposed to resemble the exact movements of the human being (2-DOF at elbow) to solve the above mentioned problem. Literature reviews and design model are discussed in detail to support the proposal that has been made. Forward and inverse Kinematic relationships are also obtained for the joint link parameter. This humanoid robot arm which has been designed and developed is one of the modules of a human size humanoid robot RALA (Robot based on Autonomous Learning Algorithm).
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Jain, Saransh, Shubham Saboo, Catalin Iulian Pruncu, and Deepak Rajendra Unune. "Performance Investigation of Integrated Model of Quarter Car Semi-Active Seat Suspension with Human Model." Applied Sciences 10, no. 9 (May 2, 2020): 3185. http://dx.doi.org/10.3390/app10093185.
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In this paper, an integrated model of a semi-active seat suspension with a human model over a quarter is presented. The proposed eight-degrees of freedom (8-DOF) integrated model consists of 2-DOF for the quarter car model, 2-DOF for the semi-active seat suspension and 4-DOF for the human model. A magneto-rheological (MR) damper is implemented for the seat suspension. The fuzzy logic-based self-tuning (FLST) proportional–integral–derivative (PID) controller allows to regulate the controlled force on the basis of sprung mass velocity error and its derivative as input. The controlled force is tracked by the Heaviside step function which determines the supply voltage for the MR damper. The performance of the proposed integrated model is analysed, in-terms of human head accelerations, for several road profiles and at different speeds. The performance of the semi-active seat suspension is compared with the traditional passive seat suspension to validate the effectiveness of the proposed integrated model with a semi-active seat suspension. The simulation results show that the semi-active seat suspension improves the ride comfort significantly by reducing the head acceleration effectively compared to the passive seat suspension.
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Geonea, Ionut Daniel, Cătălin Alexandru, Alexandru Margine, and Alin Ungureanu. "Design and Simulation of a Single DOF Human-Like Leg Mechanism." Applied Mechanics and Materials 332 (July 2013): 491–96. http://dx.doi.org/10.4028/www.scientific.net/amm.332.491.
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In this paper is carried out the selection and simulation of a one degrees of freedom (DOF) leg mechanism. The leg mechanism consist of a nine bar linkage and is based on a Low-cost Easy-operation idea. Virtual simulation tests of the model shows the feasible of the proposed leg mechanism, for human leg motion assistance. Kinematics and dynamics analysis of the leg mechanism is carried out. Finally, dynamic simulation results reveal the motion characteristics and performance of the leg mechanism.
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IVANCEVIC, VLADIMIR. "LIE–LAGRANGIAN MODEL FOR REALISTIC HUMAN BIODYNAMICS." International Journal of Humanoid Robotics 03, no. 02 (June 2006): 205–18. http://dx.doi.org/10.1142/s0219843606000680.
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We present a sophisticated Lagrangian model for anatomically and physiologically realistic human biodynamics (RHB), to accompany the recently reported Hamiltonian formulation.1 The present RHB formulation is designed around three main modules: (i) A Riemannian configuration manifold, composed of gauge Lie groups of constrained 3D rotations and translations, which includes more than 300 degrees of freedom (DOF); (ii) exterior Lagrangian dynamics of the human musculo-skeletal system, including all natural conservative, dissipative and driving forces, powered by 600 equivalent muscles; and (iii) hierarchical nonlinear control, based on an iterative Lie derivative formalism, resembling both spinal reflexes and coordination-control of the human cerebellum. RHB is driven by individual, user supplied musculo-skeletal data. It is modeled in the computer algebra system Mathematica™, simulated in Delphi™ and animated in the 3DS Max™ graphical environment. As an applied example of RHB, we present the full spine simulator, with 150 DOF (25 movable joints each with three constrained rotations and translations), muscular excitation and contraction dynamics, spring-and-damper ligament-like dynamics, spinal-like and cerebellar-like control, and external torques and forces (including inertial, gravitational, viscous, elastic and various types of impacts).
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Fukui, Kotaro, Yuma Ishikawa, Eiji Shintaku, Masaaki Honda, and Atsuo Takanishi. "Anthropomorphic Talking Robot Based on Human Biomechanical Structure." Advances in Science and Technology 58 (September 2008): 153–58. http://dx.doi.org/10.4028/www.scientific.net/ast.58.153.
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We developed an anthropomorphic talking robot, Waseda Talker No. 6 (WT-6), which generates speech sounds by mechanically simulating articulatory motions and aero-acoustic phenomena. WT-6 possesses 17 degrees of freedom (DOF): a 5-DOF tongue, 1-DOF jaws, 4-DOF lips, a nasal cavity, and a 1-DOF soft palate as articulators; and 5-DOF vocal cords and 1-DOF lungs as vocal organs. The vocal cords, tongue, and lips are made from the thermoplastic rubber Septon, whose elasticity is similar to that of human tissue. WT-6 has three-dimensional (3D) lips, tongue, jaw, and velum, which form the vocal tract structure. It also has an independent jaw opening/closing mechanism. The previous robot in the series had a two-dimensional tongue and could not produce human-like tongue shape. The new tongue can form 3D shapes, and thus, is able to produce more realistic vocal tract shapes. The vocal cord model consists of two folds, and is constructed with a structure similar to the biomechanical structure of human vocal cords. These vocal cords can vibrate in complex phases, similar to those of a human. With these mechanisms, the robot can reproduce human speech in a more biomechanical manner, and thus, can produce a voice closer to that of a human.
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Ramamurthy, N. V., B. K. Vinayagam, and J. Roopchand. "Comfort Level Refinement of Military Tracked Vehicle Crew through Optimal Control Study." Defence Science Journal 68, no. 3 (April 16, 2018): 265. http://dx.doi.org/10.14429/dsj.68.12002.
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Military tracked vehicle and crew are modelled together in this paper as integrated man-machine lumped parameter model, by integrating the simplified 5 degrees of freedom (DoF) tracked vehicle model, including seat and 4 DoF human bio-dynamic model, thus resulting in a 9 DoF simplified vehicle-occupant model. Then the natural frequency of major mass segment namely the chassis mass is obtained through simulation study, for a known road input. The value obtained is compared with that of an earlier research work, for validation of said man-machine model. Then focusing our study locally at crew seat location, parameters of crew seat suspension for ride comfort are optimised using the optimal digital state space controller designed for this purpose by implementing it in a 2 DoF occupant - seat suspension model and its Simulink model constructed. Simulation results illustrate the attainment of the goal by meeting the controller design requirements.
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Crenganis, Mihai, and Octavian Bologa. "Another Approach for Redundancy Resolution of a 7 DOF Robotic Arm." Applied Mechanics and Materials 762 (May 2015): 305–11. http://dx.doi.org/10.4028/www.scientific.net/amm.762.305.
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In this paper we have presented a method to solve the inverse kinematics problem of a redundant robotic arm with seven degrees of freedom and a human like workspace based on mathematical equations, Fuzzy Logic implementation and Simulink models. For better visualization of the kinematics simulation a CAD model that mimics the real robotic arm was created into SolidWorks® and then the CAD parts were converted into SimMechanics model.
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Boyack, Michael, Alexsandra Sices, and Bruce Woongyeol Jo. "3D human hands rendering by a six degrees of freedom collaborative robot and a single 2D camera." IAES International Journal of Robotics and Automation (IJRA) 12, no. 2 (June 1, 2023): 125. http://dx.doi.org/10.11591/ijra.v12i2.pp125-136.
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Human hands are essential in everyday tasks, mainly manipulating and grasping objects. Thus, accurate and precise three-dimensional (3D) models of digitally reconstructed hands are valuable to the world of ergonomics. A 3D scan-to-render system called the “3D hands model rendering using a 6-degrees of freedom (DoF) collaborative robot” is proposed to ensure that a person receives the best possible outcome for their unique anatomy. The description implies this is using a 6-DoF robot with a two-dimensional (2D) camera sensor that will encompass all forms of the production line in a timely, low-cost, precise, and accurate manner so that an individual can go to and scan their hand and have an actual 3D reconstruction print within the same facility, the same day. It is expected to generate an accurate hand model using structure from motion (SFM) system techniques to create a dense point cloud using photogrammetry. The point cloud is used to develop the tetrahedral mesh of the surface of the hand. This mesh is then refined to filter out the noise of the point cloud. The mesh can produce a precise 3D model that can tailor products to the consumer's needs. The results show the effectiveness of the 3D model of the hand.
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Nomura, Kenta, Teru Yonezawa, Hiroshi Takemura, and Hiroshi Mizoguchi. "Development of Six-DOF Human Ankle Motion Control Device Using Stewart Platform Structure for Fall Prevention." Journal of Robotics and Mechatronics 28, no. 5 (October 20, 2016): 654–63. http://dx.doi.org/10.20965/jrm.2016.p0654.
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[abstFig src='/00280005/06.jpg' width='300' text='Developed device' ] According to a worldwide WHO survey, about one-third of people at the age of 65 or older experience at least one fall a year, which may result in a severe injury. Meanwhile, the population of the developed world is increasingly aging, and fall incidents can be therefore considered as a global problem. The causes of falls include the weakening of the tibialis anterior and gastrocnemius muscles that respectively play important roles in the dorsal and plantar flexion of the foot, and deterioration of the functions necessary to recover balance from perturbations during gait. Such dysfunctions are treated with rehabilitation provided by physical therapists and with special gait training in which the patient is subjected to perturbations. Although devices for rehabilitation and gait training have been developed, they are problematic since they only allow the ankle joint to move at a low number of degrees of freedom (DOF). In this study, we developed an ankle foot orthosis to provide six-DOF control of the ankle joint using a parallel link mechanism known as a Stewart platform. The Stewart platform construction makes it possible to provide six-DOF control. Since the ankle foot orthosis can be applied to walking, it can assist walking or gait training. In one of our prior studies, we proposed a force control method for the device, and verified its accuracy. In the present study, we improved the attachment method and introduced a pressure sensor to the previous version of the device to allow implementation of a new method that enables control adapted to the human gait. In addition, we conducted four experiments to verify whether it is possible to reproduce the physical therapist’s rehabilitation manipulations without limiting the ankle joint’s DOF, provide arbitrary walking assist action, and impart perturbations to the subject during gait. The first experiment verified the device’s accuracy in reproducing motion, the second confirmed the dispersion of the reproduced motion, the third assessed the walking-assist performance to prevent trips, and the fourth ascertained whether it is possible to make the subject lose balance by the imparted perturbation. The results demonstrated that the motions can be reproduced with high accuracy and with low dispersion and that the ankle joint motions can be controlled adaptively to fit the subject’s gait, suggesting the usefulness of the proposed device.
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Crenganis, Mihai, Radu Breaz, Gabriel Racz, and Octavian Bologa. "Kinematic Solutions of a 7 DOF Robotic Arm Using Redundancy Circle and Fuzzy Models." Applied Mechanics and Materials 555 (June 2014): 320–26. http://dx.doi.org/10.4028/www.scientific.net/amm.555.320.
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In this paper we have presented a method to solve the inverse kinematics problem of a redundant robotic arm with seven degrees of freedom and a human like workspace based on mathematical equations, Fuzzy Logic implementation and Simulink models. For better visualization of the kinematics simulation a CAD model that mimics the real robotic arm was created into SolidWorks® and then the CAD parts were converted into SimMechanics model.
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Zana, Roland, Bálint Bodor, László Bencsik, and Ambrus Zelei. "A Tutorial for the Analysis of the Piecewise-Smooth Dynamics of a Constrained Multibody Model of Vertical Hopping." Mathematical and Computational Applications 23, no. 4 (November 14, 2018): 74. http://dx.doi.org/10.3390/mca23040074.
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Contradictory demands are present in the dynamic modeling and analysis of legged locomotion: on the one hand, the high degrees-of-freedom (DoF) descriptive models are geometrically accurate, but the analysis of self-stability and motion pattern generation is extremely challenging; on the other hand, low DoF models of locomotion are thoroughly analyzed in the literature; however, these models do not describe the geometry accurately. We contribute by narrowing the gap between the two modeling approaches. Our goal is to develop a dynamic analysis methodology for the study of self-stable controlled multibody models of legged locomotion. An efficient way of modeling multibody systems is to use geometric constraints among the rigid bodies. It is especially effective when closed kinematic loops are present, such as in the case of walking models, when both legs are in contact with the ground. The mathematical representation of such constrained systems is the differential algebraic equation (DAE). We focus on the mathematical analysis methods of piecewise-smooth dynamic systems and we present their application for constrained multibody models of self-stable locomotion represented by DAE. Our numerical approach is demonstrated on a linear model of hopping and compared with analytically obtained reference results.
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Crenganis, Mihai, Radu Eugen Breaz, Sever Gabriel Racz, and Octavian Bologa. "Inverse Kinematics for a 7 DOF Robotic Arm Using the Redundancy Circle and ANFIS Models." Applied Mechanics and Materials 657 (October 2014): 823–28. http://dx.doi.org/10.4028/www.scientific.net/amm.657.823.
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In this paper we have presented a method to solve the inverse kinematics problem of a redundant robotic arm with seven degrees of freedom and a human like workspace based on mathematical equations, ANFIS implementation and Simulink models. For better visualization of the kinematics simulation a CAD model that mimics the real robotic arm was created into SolidWorks® and then the CAD parts were converted into SimMechanics model.
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Korondi, Pe´ter, Pe´ter T. Szemes, and Hideki Hasimoto. "Sliding Mode Friction Compensation for a 20 DOF Sensor Glove." Journal of Dynamic Systems, Measurement, and Control 122, no. 4 (March 1, 2000): 611–15. http://dx.doi.org/10.1115/1.1317232.
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A high-performance human interface device needs accurate force feedback from the manipulated environment to the operator to improve the operation. The mechanism applied in the human interface device usually has a reasonable imminent friction. This friction must be compensated in a way that the operator cannot feel this friction force but only the force from the manipulated environment. The main contribution of this paper is a practical application of direct model based chattering free sliding mode friction estimator and compensator for a human interface device, which is used for virtual telemanipulation. Experimental results are presented for a sensor glove type haptic device with 20 degrees of freedom. [S0022-0434(00)01104-7]
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YANG, JINGZHOU (JAMES). "WORKSPACE OF DIGITAL HUMAN LOWER EXTREMITIES." International Journal of Humanoid Robotics 06, no. 02 (June 2009): 291–306. http://dx.doi.org/10.1142/s0219843609001735.
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This paper presents an applicable formula for determining the workspace of digital human lower extremities. The digital human model has over 100 degrees of freedom (DOF): 94 in the upper body, 14 in the lower extremities, 5 in the neck, 4 in the eyes, and 25 for each hand. The Jacobian row rank deficiency criteria are implemented to determine the singular surfaces that finally form the workspace. The use of this digital human model for determining workspace offers several advantages over direct measurement: (1) the workspace can be visualized in real-time based on offline computation, (2) the workspace can be used for the ergonomic design of products in the virtual prototyping stage, and (3) the calculated workspace includes complete information about the envelope and inside characteristics.
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Junius, Karen, Marc Degelaen, Nina Lefeber, Eva Swinnen, Bram Vanderborght, and Dirk Lefeber. "Bilateral, Misalignment-Compensating, Full-DOF Hip Exoskeleton: Design and Kinematic Validation." Applied Bionics and Biomechanics 2017 (2017): 1–14. http://dx.doi.org/10.1155/2017/5813154.
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A shared design goal for most robotic lower limb exoskeletons is to reduce the metabolic cost of locomotion for the user. Despite this, only a limited amount of devices was able to actually reduce user metabolic consumption. Preservation of the natural motion kinematics was defined as an important requirement for a device to be metabolically beneficial. This requires the inclusion of all human degrees of freedom (DOF) in a design, as well as perfect alignment of the rotation axes. As perfect alignment is impossible, compensation for misalignment effects should be provided. A misalignment compensation mechanism for a 3-DOF system is presented in this paper. It is validated by the implementation in a bilateral hip exoskeleton, resulting in a compact and lightweight device that can be donned fast and autonomously, with a minimum of required adaptations. Extensive testing of the prototype has shown that hip range of motion of the user is maintained while wearing the device and this for all three hip DOFs. This allowed the users to maintain their natural motion patterns when they are walking with the novel hip exoskeleton.
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Wang, Yingnan, Yueming Yang, and Yan Li. "Recognition and Difference Analysis of Human Walking Gaits Based on Intelligent Processing of Video Images." Traitement du Signal 37, no. 6 (December 31, 2020): 1085–91. http://dx.doi.org/10.18280/ts.370621.
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Based on the residual network and long short-term memory (LSTM) network, this paper proposes a human walking gait recognition method, which relies on the vector image of human walking features and the dynamic lower limb model with multiple degrees-of-freedom (DOFs). Firstly, a human pose estimation algorithm was designed based on deep convolutional neural network (DCNN), and used to obtain the vector image of human walking features. Then, the movements of human lower limbs were described by a simplified model, and the dynamic eigenvectors of the simplified model were obtained by Lagrange method, revealing the mapping relationship between eigenvectors in gait fitting. To analyze the difference of human walking gaits more accurately, a feature learning and recognition algorithm was developed based on residual network, and proved accurate and robust through experiments on the data collected from a public gait database.
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Chow, J. C. K. "STATISTICAL SENSOR FUSION OF A 9-DOF MEMS IMU FOR INDOOR NAVIGATION." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W7 (September 12, 2017): 333–38. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w7-333-2017.
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Sensor fusion of a MEMS IMU with a magnetometer is a popular system design, because such 9-DoF (degrees of freedom) systems are capable of achieving drift-free 3D orientation tracking. However, these systems are often vulnerable to ambient magnetic distortions and lack useful position information; in the absence of external position aiding (e.g. satellite/ultra-wideband positioning systems) the dead-reckoned position accuracy from a 9-DoF MEMS IMU deteriorates rapidly due to unmodelled errors. Positioning information is valuable in many satellite-denied geomatics applications (e.g. indoor navigation, location-based services, etc.). This paper proposes an improved 9-DoF IMU indoor pose tracking method using batch optimization. By adopting a robust in-situ user self-calibration approach to model the systematic errors of the accelerometer, gyroscope, and magnetometer simultaneously in a tightly-coupled post-processed least-squares framework, the accuracy of the estimated trajectory from a 9-DoF MEMS IMU can be improved. Through a combination of relative magnetic measurement updates and a robust weight function, the method is able to tolerate a high level of magnetic distortions. The proposed auto-calibration method was tested in-use under various heterogeneous magnetic field conditions to mimic a person walking with the sensor in their pocket, a person checking their phone, and a person walking with a smartwatch. In these experiments, the presented algorithm improved the in-situ dead-reckoning orientation accuracy by 79.8–89.5 % and the dead-reckoned positioning accuracy by 72.9–92.8 %, thus reducing the relative positioning error from metre-level to decimetre-level after ten seconds of integration, without making assumptions about the user’s dynamics.
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PARK, ILL-WOO, JUNG-YUP KIM, SEO-WOOK PARK, and JUN-HO OH. "DEVELOPMENT OF HUMANOID ROBOT PLATFORM KHR-2 (KAIST HUMANOID ROBOT 2)." International Journal of Humanoid Robotics 02, no. 04 (December 2005): 519–36. http://dx.doi.org/10.1142/s0219843605000612.
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The mechanical and electrical system designs and system integration including controllers and sensory devices of the humanoid KHR-2 are presented. The design concept and the objective are also discussed. Since 2003, we have been developing KHR-2, which has 41 DOF (degrees of freedom). Each arm of KHR-2 has 11 DOF in total: 5 DOF/hand (i.e. fingers), 2 DOF/wrist, and 4 DOF/arm. Each leg constitutes 6 DOF. The head constitutes 6 DOF (2 DOF for eyes and 2 DOF at the neck), and the trunk has 1 DOF. KHR-2 has been mechanically designed to have a human friendly appearance and also wide ranges of angular motion. Its joint actuators have been designed in order to reduce motion uncertainties such as backlash. All axes of KHR-2 are under distributed control, which reduces the computational burden on the main controller and also to facilitate device expansions. We have developed a microprocessor-based sub-controller for servo motor operations, onto which sensory feedback is interfaced. The main controller, which is mounted on the back of the robot communicates with sub-controllers in real-time through CAN (Controller Area Network). Windows XP is used as the OS (Operating System), which enables rapid program development. RTX (Real Time eXtension) HAL extension software is used to realize the real-time control in the Windows XP environment. KHR-2 has several sensor types such as 3-axis F/T (Force/Torque) sensors at the foot and wrist, an inertia sensor system (accelerometer and rate gyro), and a CCD camera. The F/T sensor at the foot is crucially important for stable walking. The inertia sensor system is essential for determining the inclination of the robot with respect to the ground.
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Svendsen, Mads Sølver, Jan Helbo, Michael Rygaard Hansen, Dejan B. Popovic, Jakob Stoustrup, and Mikkel Melters Pedersen. "AAU-BOT1: A Platform for Studying Dynamic, Life-Like Walking." Applied Bionics and Biomechanics 6, no. 3-4 (2009): 285–99. http://dx.doi.org/10.1155/2009/326956.
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This paper describes the development of the humanoid robot AAU-BOT1. The purpose of the robot is to investigate human-like walking and in this connection, test prosthetic limbs. AAU-BOT1 has been designed with modularity in mind making it possible to replace, e.g. the lower leg to test transfemoral or transtibial prosthesis or orthosis. Recorded motion data from a male test person, along with approximated inertial and mass properties, were used to determine necessary joint torques in human walking which was used as design parameters for the robot. The robot has 19 degrees of freedom (DoF), 17 actuated and 2 unactuated acting as passive toe joints. The project was granted 60,000 Euro, and to keep development costs below this, the development and instrumentation was carried out by three groups of master students from the Department of Mechanical Engineering (ME) and the Department of Electronic Systems at Aalborg University and supported by the Department of Health Sciences and Technology (HST). To further reduce the cost, the robot uses off-the-shelf hardware which also reduced the time from idea to practical implementation. The result is a low-cost humanoid robot fully assembled and equipped with sensors ready to take its first steps.
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Mohan Varma, D. S., and S. Sujatha. "Segmental contributions to the ground reaction force in the single support phase of gait." Mechanical Sciences 5, no. 2 (August 19, 2014): 37–52. http://dx.doi.org/10.5194/ms-5-37-2014.
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Abstract. An inverse dynamics model for the single support (SS) phase of gait is developed to study segmental contributions to the ground reaction force (GRF). With segmental orientations as the generalized degrees of freedom (DOF), the acceleration of the body's center-of-mass is expressed analytically as the summation of the weighted kinematics of individual segments. The weighting functions are constants that are functions of the segment masses and center-of-mass distances. Using kinematic and anthropometric data from literature as inputs, and using the roll-over-shape (ROS) to model the foot-ground interaction, GRF obtained from the inverse model are compared with measured GRF data from literature. The choice of the generalized coordinates and mathematical form of the model provides a means to weigh individual segment contributions, simplify models and choose more kinetically accurate inverse dynamics models. For the kinematic data used, an anthropomorphic model that includes the frontal plane rotation of the pelvis in addition to the sagittal DOF of the thigh and shank most accurately captures the vertical component of the GRF in the SS phase of walking. Of the two ROS used, the ankle-foot roll-over shape provides a better approximation of the kinetics in the SS phase. The method presented here can be used with additional experimental studies to confirm these results.
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Ahmed, Mohammed, M. S. Huq, and B. S. K. K. Ibrahim. "Kinematic Modelling of FES Induced Sit-to-stand Movement in Paraplegia." International Journal of Electrical and Computer Engineering (IJECE) 7, no. 6 (December 1, 2017): 3060. http://dx.doi.org/10.11591/ijece.v7i6.pp3060-3069.
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FES induced movements from indication is promising due to encouraging results being obtained by scholars. The kinematic model usually constitute the initial phase towards achieving the segmental dynamics of any rigid body system. It can be used to ascertain that the model is capable of achieving the desired goal. The dynamic model builds on the kinematic model and is usually mathematically cumbersome depending on the number of degrees-of-freedom. This paper presents a kinematic model applicable for human sit-to-stand movement scenario that will be used to obtain the dynamic model the FES induced movement in a later study. The study shows that the 6 DOF conceptualized sit-to-stand movement can be achieved conveniently using 4 DOF. The 4 DOF has an additional joint compared to similar earlier works which makes more it accurate and flexible. It is more accurate in the sense that it accommodates additional joint i.e. the neck joint whose dynamics could be captured. And more flexible in the sense that if future research uncover more contributions by the segments it can be easily incorporated including that of other segments e.g. the trunk, neck and upper limbs.
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Liu, Fang, Wen Ming Cheng, and Yi Zhou. "Finite Element Analysis of the Mechanical Structure in Portable Exoskeleton Based on DOF Coupling." Advanced Materials Research 706-708 (June 2013): 1140–45. http://dx.doi.org/10.4028/www.scientific.net/amr.706-708.1140.
Full textAbstract:
Since the posture of portable exoskeleton is consistent with human motion and each joint degree of freedom is same, on the basis of DOF coupling in portable exoskeleton, the finite element analysis of the mechanical structure in portable exoskeleton has been calculated. According to the anthropomorphic mechanism design method, the universal joint structure has been used to meet the requirements of degrees of freedom in the mechanical structure of the exoskeleton; using the Hydraulic cylinder to simulate the contraction or stretch of human muscle, and the three-dimensional model of the exoskeleton mechanical systems has been created with the Solidworks software; selecting Human CAD software and setting the parameters of the movement of the human body model, the variations of the various joints can be obtained; using the Parasolid as the standard format for data transfer between the two software Solidworks and ANSYS, the finite element analysis model was established, and according to the principle of coupling, the three translational DOF and two rotating DOF was coupled, besides through both legs vertical standing, one knee kneeling, and one leg vertical standing three conditions, the exoskeleton strength was analyzed. The simulation results show that under the three conditions, a concentrated stress all has been found in the exoskeleton structure, besides the concentrated stresses all have been obtained in the cross-section changing site or the junction of the two components, which stress values exceeded the allowable stress values of the aluminum alloy material, so the suggestions for improvement of the structure are put forward in the article; at the same time, the simulation results provide a numerical basis for the optimization of the portable exoskeleton structure.
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Manna, Soumya Kanti, and Subhasis Bhaumik. "A Bioinspired 10 DOF Wearable Powered Arm Exoskeleton for Rehabilitation." Journal of Robotics 2013 (2013): 1–15. http://dx.doi.org/10.1155/2013/741359.
Full textAbstract:
The developed exoskeleton device (Exorn) has ten degrees of freedom to control joints starting from shoulder griddle to wrist to provide better redundancy, portability, and flexibility to the human arm motion. A 3D conceptual model is being designed to make the system wearable by human arm. All the joints are simple revolute joints with desired motion limit. A Simulink model of the human arm is being developed with proper mass and length to determine proper torque required for actuating those joints. Forward kinematics of the whole system has been formulated for getting desired dexterous workspace. A proper and simple Graphical User Interface (GUI) and the required embedded system have been designed for providing physiotherapy lessons to the patients. In the literature review it has been found that researchers have generally ignored the motion of shoulder griddle. Here we have implemented those motions in our design. It has also been found that people have taken elbow pronation and supination motion as a part of shoulder internal and external rotation though both motions are quite different. A predefined resolved motion rate control structure with independent joint control is used so that all movements can be controlled in a predefined way.
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Rajkumar, Sam Prasanna, Sudesh Sivarasu, and Lazar Mathew. "COMPARATIVE KINEMATIC ANALYSIS OF THE RANGE OF MOVEMENT OF A NORMAL HUMAN KNEE JOINT, STANDARD ARTIFICIAL KNEE AND NOVEL ARTIFICIAL HIGH FLEXION KNEE." Biomedical Engineering: Applications, Basis and Communications 22, no. 01 (February 2010): 41–45. http://dx.doi.org/10.4015/s1016237210001700.
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Total Knee Arthroplasty (TKA) using standard artificial knee implant has a limitation in restriction in the range of motion and freedom of movements'. This study was worked out to compare the kinematics of a reconstructed 3D knee with standard and high flexion artificial knee designs. A CT bone model reconstructed with MIMICS for a 3D normal knee joint and the simulation was done for normal knee, standard version of artificial knee as well as the high flexion knee designs. The results of the analyses, provides us an insight that high flexion designs were most suited and gives increased range of motion and also provides an additional degree of freedom so that it almost mimics the normal knee movement. The high flexion design when tested under simulated environment provided a better functionality and increased movements. It was concluded that the normal knee has 6 degrees of freedom (DOF); the standard version has 1 rotation and 1 translation. The high flexion design provides 2 rotations and 1 translation.
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MARZBANRAD, JAVAD, and AMIR AFKAR. "A BIOMECHANICAL MODEL AS A SEATED HUMAN BODY FOR CALCULATION OF VERTICAL VIBRATION TRANSMISSIBILITY USING A GENETIC ALGORITHM." Journal of Mechanics in Medicine and Biology 13, no. 04 (July 7, 2013): 1350053. http://dx.doi.org/10.1142/s021951941350053x.
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Many biomechanical models of whole body vibrations have been developed, as part of the design, optimization, and vibrations control of vehicle seat systems, with the aim of achieving greater comfort. Most of these models are complex and result in large errors. In this paper, we introduce two new models, with and without backrest support, within a specific frequency domain. One is an optimized seven-degrees-of-freedom (7-DoF) lumped-parameter model with a unique structure to display vertical vibrations in one direction. The other is a new type of model called the coupled model, where the stiffness and damping matrices are employed instead of the spring and damper scalar parameters to present vertical vibrations in two directions — vertical and horizontal. The use of matrices not only simplifies and reduces DoF, but also gives more accurate results in comparison with the conventional multi-body models. With the help of a genetic algorithm (GA) through the global criterion method, we obtained numerical parameters of both models including mass, stiffness, and damping, which minimized the errors. The mean error for the 7-DoF model was 2.2%, while the best lumped-parameter models previously developed produced 12.6%. For the coupled model, we measured a mean error of 7%, a significant improvement over a well-known multi-body model with a mean error of 22.4%. Finally, we compared the transmissibility of vibrations in the human body applying the two models in the frequency range below 6 Hz, in both cases of with and without a backrest. These confirmed the importance of the backrest.
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Khadiv, Majid, S. Ali A. Moosavian, Aghil Yousefi-Koma, Majid Sadedel, and Saeed Mansouri. "Optimal gait planning for humanoids with 3D structure walking on slippery surfaces." Robotica 35, no. 3 (September 1, 2015): 569–87. http://dx.doi.org/10.1017/s0263574715000715.
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SUMMARYIn this study, a gait optimization routine is developed to generate walking patterns which demand the lowest friction forces for implementation. The aim of this research is to fully address the question “which walking pattern demands the lowest coefficient of friction amongst all feasible patterns?”. To this end, first, the kinematic structure of the considered 31 DOF (Degrees of Freedom) humanoid robot is investigated and a closed-form dynamics model for its lower-body is developed. Then, the medium through which the walking pattern generation is conducted is presented. In this medium, after designing trajectories for the feet and the pelvis, the joint space variables are obtained, using the inverse kinematics. Finally, by employing a genetic algorithm (GA), an optimization process is conducted to generate walking patterns with the minimum Required Coefficient Of Friction (RCOF). Six parameters are adopted to parameterize the pelvis trajectory and are exploited as the design variables in this optimization procedure. Also, a parametrical study is accomplished to address the effects of some other variables on RCOF. For comparison purposes, a tip-over Stability Margin (SM) is defined, and an optimization procedure is conducted to maximize this margin. Finally, the proposed gait planning procedure is implemented on SURENA III, a humanoid robot designed and fabricated in CAST, to validate the developed simulation procedure. The obtained results reveal merits of the proposed optimal gait planning procedure in terms of RCOF.
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Khan, Said G., Guido Herrmann, Alexander Lenz, Mubarak Al Grafi, Tony Pipe, and Chris Melhuish. "Compliance Control and Human–Robot Interaction: Part II — Experimental Examples." International Journal of Humanoid Robotics 11, no. 03 (September 2014): 1430002. http://dx.doi.org/10.1142/s0219843614300025.
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Compliance control is highly relevant to human safety in human–robot interaction (HRI). This paper presents multi-dimensional compliance control of a humanoid robot arm. A dynamic model-free adaptive controller with an anti-windup compensator is implemented on four degrees of freedom (DOF) of a humanoid robot arm. The paper is aimed to compliment the associated review paper on compliance control. This is a model reference adaptive compliance scheme which employs end-effector forces (measured via joint torque sensors) as a feedback. The robot's body-own torques are separated from external torques via a simple but effective algorithm. In addition, an experiment of physical human robot interaction is conducted employing the above mentioned adaptive compliance control along with a speech interface. The experiment is focused on passing an object (a cup) between a human and a robot. Compliance is providing an immediate layer of safety for this HRI scenario by avoiding pushing, pulling or clamping and minimizing the effect of collisions with the environment.
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Liu, J. H., B. Li, Q. Ning, M. Zhou, Y. X. Li, M. C. Liu, and K. Xu. "Mechanical design of a passive lower-limb exoskeleton for load-carrying assistance." Journal of Physics: Conference Series 2213, no. 1 (March 1, 2022): 012035. http://dx.doi.org/10.1088/1742-6596/2213/1/012035.
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Abstract This paper presents a passive exoskeleton with 17 degrees-of-freedom (DOF) for load-carrying, which includes two 3DOFs ankle joint, two 2DOFs hip joint, two 1DOF knee joint, one 1DOF backpack, and two redundant DOFs at the thigh and shank, respectively, to improve the compatibility of human-machine locomotion. The modular backpack was designed to facilitate carrying of different loads. A horn-shaped spatial mechanism was designed to connect the hip joint and the backpack, and transfer the payload to the ground. A tension spring was adopted to absorb the gravitational potential energy of the load when walking, and fix the horn-shaped spatial mechanism at both sides. The segmented brace at the thigh and the shank were designed to adjust different legs. In order to improve the force transmission performance, we cancelled the extension DOF of the hip joint, and moved the rotation axis of the knee joint backward. The knee joint assistance mechanism was designed to allow the knee joint move freely when the flexion angle did not exceed 60°. However, when the knee bends over 60°, the knee joint presses the torsion spring to store energy. After then, it releases energy to assist knee extending. The Cooper-Harper scale tests demonstrated that the exoskeleton had excellent static support effect and movement flexibility, which verified the rationality of the exoskeleton design.
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Hoffmann, Kathrin, Daniel Müller, René Simon, and Oliver Sawodny. "On trajectory tracking control of fluid-driven actuators." at - Automatisierungstechnik 69, no. 11 (November 1, 2021): 970–80. http://dx.doi.org/10.1515/auto-2021-0099.
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Abstract Fluid-driven actuators are not only well-established in automation, but also a promising drive technology for collaborative robots. Their inherent compliance due to the compressibility of suitable fluids such as air, as well as their direct drive properties are advantageous safety features for human-machine collaboration. In this work, we provide an overview of different fluid-driven manipulators, namely fluidic muscle actuated ones, continuum manipulators, and those with rotary joints. For the latter, we introduce the mathematical model including mechanics and pressure dynamics and describe its properties such as strong nonlinearities, which make trajectory tracking control challenging. A model-based nonlinear cascaded controller is presented. Experimental results on a 6 degrees of freedom (DOF) prototype demonstrate the resulting trajectory tracking performance.
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McKenna, Michael, and David Zeltzer. "Dynamic Simulation of a Complex Human Figure Model with Low Level Behavior Control." Presence: Teleoperators and Virtual Environments 5, no. 4 (January 1996): 431–56. http://dx.doi.org/10.1162/pres.1996.5.4.431.
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Advances in computer hardware and software technology allow the simulation of natural phenomena in increasing levels of complexity. This research is concerned with simulating the articulated movements of humans using the laws of physical motion, and contributes to the fields of computer animation and biomechanics. A 90 degree of freedom model of a human figure is developed, and an efficient dynamic simulator is employed to create and analyze physically based, computer-generated motions. The foot of the simulated human figure has been modeled with a significant amount of kinematic complexity, with 28 degrees of freedom per foot. A joint-level control layer uses springs and dampers to control postures and movements. Inverse dynamics and inverse control can be used to calibrate the spring actuators to exactly achieve specified postural goals. A framework for higher level control is implemented, although specific tasks require tailored control strategies. Several example tasks are simulated and described, including a stable standing posture and the stepping phase of walking using passive dynamic effects to generate much of the motion. Together, the simulator and biomechanical model create a framework that can be used to address problems in computer animation and biomechanical research, and eventually, in a clinical setting, to assist doctors in analyzing the problems of specific patients.
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Gupta, Gaurav, and Ashish Dutta. "Trajectory generation and step planning of a 12 DoF biped robot on uneven surface." Robotica 36, no. 7 (February 26, 2018): 945–70. http://dx.doi.org/10.1017/s0263574718000188.
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SUMMARYOne of the primary goals of biped locomotion is to generate and execute joint trajectories on a corresponding step plan that takes the robot from a start point to a goal while avoiding obstacles and consuming as little energy as possible. Past researchers have studied trajectory generation and step planning independently, mainly because optimal generation of robot gait using dynamic formulation cannot be done in real time. Also, most step-planning studies are for flat terrain guided by search heuristics. In the proposed method, a framework for generating trajectories as well as an overall step plan for navigation of a 12 degrees of freedom biped on an uneven terrain with obstacles is presented. In order to accomplish this, a dynamic model of the robot is developed and a trajectory generation program is integrated with it using gait variables. The variables are determined using a genetic algorithm based optimization program with the objective of minimizing energy consumption subject to balance and kinematic constraints of the biped. A database of these variables for various terrain angles and walking motions is used to train two neural networks, one for real-time trajectory generation and another for energy estimation. To develop a global navigation strategy, a weighted A* search is used to generate the footstep plan with energy considerations in sight. The efficacy of the approach is exhibited through simulation-based results on a variety of terrains.
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Du, Qiwei, Heting Bai, and Zhongpan Zhu. "Intelligent Evaluation Method of Human Cervical Vertebra Rehabilitation Based on Computer Vision." Sensors 23, no. 8 (April 8, 2023): 3825. http://dx.doi.org/10.3390/s23083825.
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With the changes in human work and lifestyle, the incidence of cervical spondylosis is increasing substantially, especially for adolescents. Cervical spine exercises are an important means to prevent and rehabilitate cervical spine diseases, but no mature unmanned evaluating and monitoring system for cervical spine rehabilitation training has been proposed. Patients often lack the guidance of a physician and are at risk of injury during the exercise process. In this paper, we first propose a cervical spine exercise assessment method based on a multi-task computer vision algorithm, which can replace physicians to guide patients to perform rehabilitation exercises and evaluations. The model based on the Mediapipe framework is set up to construct a face mesh and extract features to calculate the head pose angles in 3-DOF (three degrees of freedom). Then, the sequential angular velocity in 3-DOF is calculated based on the angle data acquired by the computer vision algorithm mentioned above. After that, the cervical vertebra rehabilitation evaluation system and index parameters are analyzed by data acquisition and experimental analysis of cervical vertebra exercises. A privacy encryption algorithm combining YOLOv5 and mosaic noise mixing with head posture information is proposed to protect the privacy of the patient’s face. The results show that our algorithm has good repeatability and can effectively reflect the health status of the patient’s cervical spine.
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Liu, De-Shin, Jen-Chang Lu, Meng-Shiun Tsai, Chih-Ta Wu, and Zhen-Wei Zhuang. "Development of a Novel Dynamic Modeling Approach for a Three-Axis Machine Tool in Mechatronic Integration." Machines 10, no. 11 (November 21, 2022): 1102. http://dx.doi.org/10.3390/machines10111102.
Full textAbstract:
This paper proposes a novel, fast, and automatic modeling method to build a virtual model with minimum degrees of freedom (DOFs) without the need for FE models or human judgment. The proposed program uses the iterative closest point (ICP) algorithm to analyze the mode shape vector of structural dynamic characteristics to define the position and DOFs of the joints between structural components. After the multi-body dynamics model was developed in software, it was converted into an SSM to connect the servo loop model. Then, the mechatronic integration analysis was performed to verify the dynamic characteristics of the tool center point (TCP) and the workbench in the experiment and simulation. The model created by the proposed identification process has a small DOF and can accurately simulate the dynamic characteristics of a machine. This model can be used for dynamic testing and control strategy development in mechatronic integration.
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Vaida, Calin, Bogdan Gherman, Doina Pislă, and Nicolae Plitea. "A CT-Scan Compatible Robotic Device for Needle Placement in Medical Applications." Advanced Engineering Forum 8-9 (June 2013): 574–83. http://dx.doi.org/10.4028/www.scientific.net/aef.8-9.574.
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Several medical applications require devices capable of placing different substances inside the human body. Due to the nature of the task it is desirable to perform these actions with visual feedback, whereas the most viable solution, especially for deep target points, is computer tomography (CT). The paper presents an innovative device, which can be fitted inside the CT gantry, and has decoupled motions to ensure maximum accuracy during the needle placement. It will be shown that for needle placement tasks 5 degrees of freedom (DOF) are sufficient to achieve the task. The geometric and kinematic model of the robot will be presented. The workspace and precision mapping are computed. Some simulation results will show the robot capabilities as well as its placement in the CT scan environment.
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Kim, Joon-young, James K. Mills, Albert H. Vette, and Milos R. Popovic. "Optimal Combination of Minimum Degrees of Freedom to be Actuated in the Lower Limbs to Facilitate Arm-Free Paraplegic Standing." Journal of Biomechanical Engineering 129, no. 6 (March 16, 2007): 838–47. http://dx.doi.org/10.1115/1.2800767.
Full textAbstract:
Arm-free paraplegic standing via functional electrical stimulation (FES) has drawn much attention in the biomechanical field as it might allow a paraplegic to stand and simultaneously use both arms to perform daily activities. However, current FES systems for standing require that the individual actively regulates balance using one or both arms, thus limiting the practical use of these systems. The purpose of the present study was to show that actuating only six out of 12 degrees of freedom (12-DOFs) in the lower limbs to allow paraplegics to stand freely is theoretically feasible with respect to multibody stability and physiological torque limitations of the lower limb DOF. Specifically, the goal was to determine the optimal combination of the minimum DOF that can be realistically actuated using FES while ensuring stability and able-bodied kinematics during perturbed arm-free standing. The human body was represented by a three-dimensional dynamics model with 12-DOFs in the lower limbs. Nakamura’s method (Nakamura, Y., and Ghodoussi, U., 1989, “Dynamics Computation of Closed-Link Robot Mechanisms With Nonredundant and Redundant Actuators,” IEEE Trans. Rob. Autom., 5(3), pp. 294–302) was applied to estimate the joint torques of the system using experimental motion data from four healthy subjects. The torques were estimated by applying our previous finding that only 6 (6-DOFs) out of 12-DOFs in the lower limbs need to be actuated to facilitate stable standing. Furthermore, it was shown that six cases of 6-DOFs exist, which facilitate stable standing. In order to characterize each of these cases in terms of the torque generation patterns and to identify a potential optimal 6-DOF combination, the joint torques during perturbations in eight different directions were estimated for all six cases of 6-DOFs. The results suggest that the actuation of both ankle flexion∕extension, both knee flexion∕extension, one hip flexion∕extension, and one hip abduction∕adduction DOF will result in the minimum torque requirements to regulate balance during perturbed standing. To facilitate unsupported FES-assisted standing, it is sufficient to actuate only 6-DOFs. An optimal combination of 6-DOFs exists, for which this system can generate able-bodied kinematics while requiring lower limb joint torques that are producible using contemporary FES technology. These findings suggest that FES-assisted arm-free standing of paraplegics is theoretically feasible, even when limited by the fact that muscles actuating specific DOFs are often denervated or difficult to access.
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Zhang, Yu, Xiao Bo Wu, and Hui Fang Liu. "Modeling and Simulation of Lower Extremity Exoskeleton." Applied Mechanics and Materials 487 (January 2014): 504–8. http://dx.doi.org/10.4028/www.scientific.net/amm.487.504.
Full textAbstract:
In order to make the paralyzed live on their own and return to the society to the most degree, mechanical exoskeleton technology is tried to applied in the field of auxiliary equipment. First, degrees of freedom and mechanical structure at the each joint of lower extremity exoskeleton was ascertained.Then a three dimensional modeling design for the lower extremity exoskeleton was carried out with SIEMENS NX8.0 and a walking gait on a flat for it was planned on MATLAB basing on inverted pendulum model.Finally the legs model was simulated on ADAMS.The result of the simulation was basically the same as planned gait which can better satisfy the requirement of human walking and can be used as reference for developping the physical prototype of lower extremity exoskeleton.
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Wang, Hongbo, Musong Lin, Zhennan Jin, Hao Yan, Guowei Liu, Shihe Liu, and Xinyu Hu. "A 4-DOF Workspace Lower Limb Rehabilitation Robot: Mechanism Design, Human Joint Analysis and Trajectory Planning." Applied Sciences 10, no. 13 (June 30, 2020): 4542. http://dx.doi.org/10.3390/app10134542.
Full textAbstract:
Most of currently rehabilitation robots cannot achieve the adduction/abduction (A/A) training of the hip joint and lack the consideration of the patient handling. This paper presents a four degrees of freedom (DOF) spatial workspace lower limb rehabilitation robot, and it could provide flexion/extension (F/E) training to three lower limb joints and A/A training to the hip joint. The training method is conducting the patient’s foot to complete the rehabilitation movement, and the patient could directly take training on the wheelchair and avoid frequent patient handling between the wheelchair and the rehabilitation device. Because patients own different joint range of motions (ROM), an analysis method for obtaining human joint motions is proposed to guarantee the patient’s joint safety in this training method. The analysis method is based on a five-bar linkage kinematic model, which includes the human lower limb. The human-robot hybrid kinematic model is analyzed according to the Denavit-Hartenberg (D-H) method, and a variable human-robot workspace based on the user is proposed. Two kinds of trajectory planning methods are introduced. The trajectory planning method and the human joint analysis method are validated through the trajectory tracking experiment of the prototype.
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Arbulú, M., D. Kaynov, L. Cabas, and C. Balaguer. "The Rh-1 Full-Size Humanoid Robot: Design, Walking Pattern Generation and Control." Applied Bionics and Biomechanics 6, no. 3-4 (2009): 301–44. http://dx.doi.org/10.1155/2009/974354.
Full textAbstract:
This paper is an overview of the humanoid robot Rh-1, the second phase of the Rh project, which was launched by the Robotics Lab at the Carlos III University of Madrid in 2002. The robot mechanical design includes the specifications development in order to construct a platform, which is capable of stable biped walking. At first, the robots’ weights were calculated in order to obtain the inverse dynamics and to select the actuators. After that, mechanical specifications were introduced in order to verify the robot’s structural behaviour with different experimental gaits. In addition, an important aspect is the joints design when their axes are crossed, which is called ‘Joints of Rectangular Axes’ (JRA). The problem with these joints is obtaining two or more degrees of freedom (DOF) in small space. The construction of a humanoid robot also includes the design of hardware and software architectures. The main advantage of the proposed hardware and software architectures is the use of standardised solutions frequently used in the automation industry and commercially available hardware components. It provides scalability, modularity and application of standardised interfaces and brings the design of the complex control system of the humanoid robot out of a closed laboratory to industry. Stable walking is the most essential ability for the humanoid robot. The three dimensional Linear Inverted Pendulum Model (3D-LIPM) and the Cart-table models had been used in order to achieve natural and dynamic biped walking. Humanoid dynamics is widely simplified by concentrating its mass in the centre of gravity (COG) and moving it following the natural inverted pendulum laws (3D-LIPM) or by controlling the cart motion (Cart-table model). An offline-calculated motion pattern does not guarantee the walking stability of the humanoid robot. Control architecture for the dynamic humanoid robot walking was developed, which is able to make online modifications of the motion patterns in order to adjust it to the continuously changing environment. Experimental results concerning biped locomotion of the Rh-1 humanoid robot are presented and discussed.
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Serebrennyj, V. V., A. A. Boshlyakov, S. V. Kalinichenko, A. I. Ogorodnik, and K. V. Konovalov. "Walking Robot for Moving on Vertical and Arbitrarily Oriented Surfaces." Mekhatronika, Avtomatizatsiya, Upravlenie 22, no. 11 (November 9, 2021): 585–93. http://dx.doi.org/10.17587/mau.22.585-593.
Full textAbstract:
The article deals with the design of a walking robot with gripping devices that allow the robot to move on arbitrarily oriented surfaces in space. Such robots are relevant primarily for the inspection of various industrial structures. A model of a two-support robot with gripping devices that allow it to be attached to support surfaces with a small curvature, but arbitrarily oriented in space, is proposed. To ensure attachment to the support surfaces, the robot is designed with five degrees of freedom. An important criterion is the possibility of dexterous movement on surfaces. One of the degrees of freedom of the robot was made linear, which makes it easier to step over obstacles and allows you to implement simpler walking algorithms. When the robot is attached to the supporting surfaces by two gripping devices at once, the kinematic chain is closed. This can lead to an increase in forces and moments in the robot’s links. In this paper, it is applied to use two methods of controlling the drives of the links together – the implementation of impedance control by introducing feedback on the evaluation of the moment based on the motor currents and ensuring the pliability of the gripping devices due to its own elasticity. A mathematical simulation of the robot was carried out, which showed the possibility of reducing the forces in the robot links when attaching the robot to two support surfaces at the same time. The best results were achieved when controlling the current vector of a synchronous motor and using current signals to implement impedance control.
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ZHANG, LIXUN, DA SONG, BINGJUN WANG, and FENG XUE. "HIP MOTION ANALYSIS USING PARAMETRIC MATHEMATICAL MODELING IN MIDDLE AGED TO ELDERLY ADULTS DURING WALKING." Journal of Mechanics in Medicine and Biology 18, no. 07 (November 2018): 1840004. http://dx.doi.org/10.1142/s0219519418400043.
Full textAbstract:
Human gait is influenced by changes in joints of the pelvis, hips, knees and ankles, which demonstrate three degrees of freedom. Thus, this study presents a mathematical model for the establishment of the hip rotation trajectory using measured data. We used multibody dynamics simulation software (LifeMOD) to establish a model of the human lower limb, whereby the three dimensional trajectory of the hip joint could be analyzed. We used advanced equipment to measure the trajectories of the internal rotation and external rotation of the hip joint in middle aged to elderly adults during walking. Curve fitting was used to obtain the average internal rotation and external rotation of the hip joint, and relationships between the amplitude, period, initial movement phase, subject height and walking speed were assessed. The observations from this study suggest that mathematical modeling of internal rotation and external rotation of hip joint can be performed using this approach. This modeling technique can be used to track the trajectory planning of rehabilitation robots and the external skeletons leading to improved human–computer interactions, and evaluation of response to rehabilitation.
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Xu, Ying, and Zhi Yuan Zeng. "Walking Stability Analysis for a Biped Robot Considering Ground Condition." Applied Mechanics and Materials 427-429 (September 2013): 1175–78. http://dx.doi.org/10.4028/www.scientific.net/amm.427-429.1175.
Full textAbstract:
With human characteristics of the structure of lower limb joints and simplify them, 12 degrees of freedom was equipped with for the lower extremities of biped walking robot. motion model is established and used to elaborate the movement characteristics in sagittal and lateral plane according to a particular mechanism of robot. The stability of robot in two or there dimensions is analyzed through ZMP principles and the calculation formula and measuring methods of corresponding ZMP are also concluded, Gait design data will be taken into the virtual prototype and make motion Simulation for gait, then get the simulation animation of walking straight, static turning and moves upstairs, This paper expounds the possibility of generating smooth walking trajectory with cubic interpolation. Using the dynamics simulation software to simulate the robot, the results show that the robot has the theory of stable gait, The control accuracy of joints position and the realization of desired purposes of the robot system.