Pneumatic artificial muscles(PAMs) have properties similar to biological muscles,which are widely used in robotics as actuators.It is difficult to achieve high-precision position control for robotics system driven by ...Pneumatic artificial muscles(PAMs) have properties similar to biological muscles,which are widely used in robotics as actuators.It is difficult to achieve high-precision position control for robotics system driven by PAMs.A 3-DOF musculoskeletal bionic leg mechanism is presented,which is driven by PAMs for quadruped robots.PAM is used to simulate the compliance of biological muscle.The kinematics of the leg swing is derived,and the foot desired trajectory is planned as the sinusoidal functions.The swing experiments of the musculoskeletal leg mechanism are conducted to analyse the extension and flexion of joints.A proportional integral derivative(PID) algorithm is presented for controlling the flexion/extension of the joint.The trajectory tracking results of joints and the PAM gas pressure are obtained.Experimental results show that the developed leg mechanism exhibits good biological properties.展开更多
We propose a new structure for artificial joints with a joint capsule which is designed to overcome the drawback of current prostheses that omit many functions of the lubricant and the joint capsule. The new structure...We propose a new structure for artificial joints with a joint capsule which is designed to overcome the drawback of current prostheses that omit many functions of the lubricant and the joint capsule. The new structure is composed of three components： lubricant, artificial joint and artificial joint capsule. The lubricant sealed in the capsule can not only reduce the wear of the artificial joint but also prevents the wear particles leaking into the body. So unexpected reactions between the wear particles and body can be avoided completely. A three-dimensional （3-D） finite element analysis （FEA） model was created for a bionic knee joint with capsule. The stresses and their distribution in the artificial capsule were simulated with different thickness, loadings, and flexion angles. The results show that the maximum stress occurs in the area between the artificial joint and the capsule. The effects of capsule thickness and the angles of flexion on stress are discussed in detail.展开更多
To get the movement mode and driving mechanism similar to human shoulder joint,a six degrees of freedom(DOF) serial-parallel bionic shoulder joint mechanism driven by pneumatic muscle actuators(PMAs)was designed.Howev...To get the movement mode and driving mechanism similar to human shoulder joint,a six degrees of freedom(DOF) serial-parallel bionic shoulder joint mechanism driven by pneumatic muscle actuators(PMAs)was designed.However,the structural parameters of the shoulder joint will affect various performances of the mechanism.To obtain the optimal structure parameters,the particle swarm optimization(PSO) was used.Besides,the mathematical expressions of indexes of rotation ranges,maximum bearing torque,discrete dexterity and muscle shrinkage of the bionic shoulder joint were established respectively to represent its many-sided characteristics.And the multi-objective optimization problem was transformed into a single-objective optimization problem by using the weighted-sum method.The normalization method and adaptive-weight method were used to determine each optimization index's weight coefficient;then the particle swarm optimization was used to optimize the integrated objective function of the bionic shoulder joint and the optimal solution was obtained.Compared with the average optimization generations and the optimal target values of many experiments,using adaptive-weight method to adjust weights of integrated objective function is better than using normalization method,which validates superiority of the adaptive-weight method.展开更多
The above-knee intelligent bionic leg is very helpful to amputees in the area of rehabilitation medicine. This paper first introduces the functional demand of the above-knee prosthesis design. Then, the advantages of ...The above-knee intelligent bionic leg is very helpful to amputees in the area of rehabilitation medicine. This paper first introduces the functional demand of the above-knee prosthesis design. Then, the advantages of the four-bar link mechanism and the magneto-rheological （MR） damper are analyzed in detail. The fixed position of the MR damper is optimized and a virtual prototype of knee joint is given. In the end, the system model of kinematics, dynamics, and controller are given and a control experiment is performed. The control experiment indicates that the intelligent bionic leg with multi-axis knee is able to realize gait tracking of the amputee＇s healthy leg based on semi-active control of the MR damper.展开更多
Variable Stiffness Actuation(VSA)is an efficient,safe,and robust actuation technology for bionic robotic joints that have emerged in recent decades.By introducing a variable stiffness elastomer in the actuation system...Variable Stiffness Actuation(VSA)is an efficient,safe,and robust actuation technology for bionic robotic joints that have emerged in recent decades.By introducing a variable stiffness elastomer in the actuation system,the mechanical-electric energy conversion between the motor and the load could be adjusted on-demand,thereby improving the performance of the actuator,such as the peak power reduction,energy saving,bionic actuation,etc.At present,the VSA technology has achieved fruitful research results in designing the actuator mechanism and the stiffness adjustment servo,which has been widely applied in articulated robots,exoskeletons,prostheses,etc.However,how to optimally control the stiffness of VSAs in different application scenarios for better actuator performance is still challenging,where there is still a lack of unified cognition and viewpoints.Therefore,from the perspective of optimal VSA performance,this paper first introduces some typical structural design and servo control techniques of common VSAs and then explains the methods and applications of the Optimal Variable Stiffness Control(OVSC)approaches by theoretically introducing different types of OVSC mathematical models and summarizing OVSC methods with varying optimization goals and application scenarios or cases.In addition,the current research challenges of OVSC methods and possible innovative insights are also presented and discussed in-depth to facilitate the future development of VSA control.展开更多
A bionic shoulder joint with three degree-of-freedom(DOF)driven by pneumatic muscle actuator is proposed and its corresponding kinematic model is established.The bionic shoulder is optimized by particle swam optimizat...A bionic shoulder joint with three degree-of-freedom(DOF)driven by pneumatic muscle actuator is proposed and its corresponding kinematic model is established.The bionic shoulder is optimized by particle swam optimization(PSO)with the fitness standards that the requirements of rotation indexes are met and the fluctuation of motion is kept in the lowest resolution in a pneumatic muscle actuator range.Simulation considering rotation indexes only(first simulation)is compared with the one considering both rotation indexes and motion resolution(second simulation)subsequently.Mounting position of the pneumatic muscle actuators in bionic shoulder is optimized after initializing the same condition in simulations.Results show that the fluctuations of parameters are consistent,and the parameters of the first simulation have good convergence than those of the second one.With the increase of stretch rate of the pneumatic muscle actuator,the needed length of fixed link in the center of static platform decreases in optimization.展开更多
The paper presents the design of walking leg for bionics crab-like robot, which is driven with micro servo motor. The kinematic characteristics of the bionics machine are analysed for optimized structure parameters, w...The paper presents the design of walking leg for bionics crab-like robot, which is driven with micro servo motor. The kinematic characteristics of the bionics machine are analysed for optimized structure parameters, which has been used in the robot design. A three closed loop motor control system structure for joint driver is also given, as well as the multi-joint driving system for walking robot leg.展开更多
基金Supported by the National Natural Science Foundation of China(No.51375289)Shanghai Municipal National Natural Science Foundation of China(No.13ZR1415500)Innovation Fund of Shanghai Education Commission(No.13YZ020)
文摘Pneumatic artificial muscles(PAMs) have properties similar to biological muscles,which are widely used in robotics as actuators.It is difficult to achieve high-precision position control for robotics system driven by PAMs.A 3-DOF musculoskeletal bionic leg mechanism is presented,which is driven by PAMs for quadruped robots.PAM is used to simulate the compliance of biological muscle.The kinematics of the leg swing is derived,and the foot desired trajectory is planned as the sinusoidal functions.The swing experiments of the musculoskeletal leg mechanism are conducted to analyse the extension and flexion of joints.A proportional integral derivative(PID) algorithm is presented for controlling the flexion/extension of the joint.The trajectory tracking results of joints and the PAM gas pressure are obtained.Experimental results show that the developed leg mechanism exhibits good biological properties.
基金This work has been financially supported by the National Science Foundation of China through the grant number of 50105014,"Bionic Lubrication System of Artificial Joints"The corresponding author,Dr.J H Zhang,would also like to acknowledge the financial support provided by the Science and Technology Committee of Shanghai under the grant number of 04 QMX1442partially financial support by Shanghai Leading Academic Discipline Project,Project Number:Y0102.
文摘We propose a new structure for artificial joints with a joint capsule which is designed to overcome the drawback of current prostheses that omit many functions of the lubricant and the joint capsule. The new structure is composed of three components： lubricant, artificial joint and artificial joint capsule. The lubricant sealed in the capsule can not only reduce the wear of the artificial joint but also prevents the wear particles leaking into the body. So unexpected reactions between the wear particles and body can be avoided completely. A three-dimensional （3-D） finite element analysis （FEA） model was created for a bionic knee joint with capsule. The stresses and their distribution in the artificial capsule were simulated with different thickness, loadings, and flexion angles. The results show that the maximum stress occurs in the area between the artificial joint and the capsule. The effects of capsule thickness and the angles of flexion on stress are discussed in detail.
基金the National Natural Science Foundation of China(NO.51405229)the Natural Science Foundation of Jiangsu Province of China(Nos.BK20151470 and BK20130796)
文摘To get the movement mode and driving mechanism similar to human shoulder joint,a six degrees of freedom(DOF) serial-parallel bionic shoulder joint mechanism driven by pneumatic muscle actuators(PMAs)was designed.However,the structural parameters of the shoulder joint will affect various performances of the mechanism.To obtain the optimal structure parameters,the particle swarm optimization(PSO) was used.Besides,the mathematical expressions of indexes of rotation ranges,maximum bearing torque,discrete dexterity and muscle shrinkage of the bionic shoulder joint were established respectively to represent its many-sided characteristics.And the multi-objective optimization problem was transformed into a single-objective optimization problem by using the weighted-sum method.The normalization method and adaptive-weight method were used to determine each optimization index's weight coefficient;then the particle swarm optimization was used to optimize the integrated objective function of the bionic shoulder joint and the optimal solution was obtained.Compared with the average optimization generations and the optimal target values of many experiments,using adaptive-weight method to adjust weights of integrated objective function is better than using normalization method,which validates superiority of the adaptive-weight method.
基金supported by China Postdoctoral Science Foundation(No. 20080441093)Key Laboratory Foundation of Liaoning Province(No. 2008S088)Postdoctoral Science Foundation of Northeastern University (No. 20080411)
文摘The above-knee intelligent bionic leg is very helpful to amputees in the area of rehabilitation medicine. This paper first introduces the functional demand of the above-knee prosthesis design. Then, the advantages of the four-bar link mechanism and the magneto-rheological （MR） damper are analyzed in detail. The fixed position of the MR damper is optimized and a virtual prototype of knee joint is given. In the end, the system model of kinematics, dynamics, and controller are given and a control experiment is performed. The control experiment indicates that the intelligent bionic leg with multi-axis knee is able to realize gait tracking of the amputee＇s healthy leg based on semi-active control of the MR damper.
基金National Key Research and Development Program of China[Grant No.2020YFB1313000]National Natural Science Foundation of China[Grant No.62003060,62101086,51975070]+2 种基金China Postdoctoral Science Foundation[2021M693769]Natural Science Foundation of Chongqing,China[Grant No.cstc2021jcyj-bsh0180]Scientific and Technological Research Program of Chongqing Municipal Education Commission[Grant No.KJQN202100648].
文摘Variable Stiffness Actuation(VSA)is an efficient,safe,and robust actuation technology for bionic robotic joints that have emerged in recent decades.By introducing a variable stiffness elastomer in the actuation system,the mechanical-electric energy conversion between the motor and the load could be adjusted on-demand,thereby improving the performance of the actuator,such as the peak power reduction,energy saving,bionic actuation,etc.At present,the VSA technology has achieved fruitful research results in designing the actuator mechanism and the stiffness adjustment servo,which has been widely applied in articulated robots,exoskeletons,prostheses,etc.However,how to optimally control the stiffness of VSAs in different application scenarios for better actuator performance is still challenging,where there is still a lack of unified cognition and viewpoints.Therefore,from the perspective of optimal VSA performance,this paper first introduces some typical structural design and servo control techniques of common VSAs and then explains the methods and applications of the Optimal Variable Stiffness Control(OVSC)approaches by theoretically introducing different types of OVSC mathematical models and summarizing OVSC methods with varying optimization goals and application scenarios or cases.In addition,the current research challenges of OVSC methods and possible innovative insights are also presented and discussed in-depth to facilitate the future development of VSA control.
基金supported by the National Natural Science Foundation of China(No.51405229)the Natural Science Foundation of Jiangsu Province of China (No. BK20151470)the NUAA Fundamental Research Fund(No.NS2013049)
文摘A bionic shoulder joint with three degree-of-freedom(DOF)driven by pneumatic muscle actuator is proposed and its corresponding kinematic model is established.The bionic shoulder is optimized by particle swam optimization(PSO)with the fitness standards that the requirements of rotation indexes are met and the fluctuation of motion is kept in the lowest resolution in a pneumatic muscle actuator range.Simulation considering rotation indexes only(first simulation)is compared with the one considering both rotation indexes and motion resolution(second simulation)subsequently.Mounting position of the pneumatic muscle actuators in bionic shoulder is optimized after initializing the same condition in simulations.Results show that the fluctuations of parameters are consistent,and the parameters of the first simulation have good convergence than those of the second one.With the increase of stretch rate of the pneumatic muscle actuator,the needed length of fixed link in the center of static platform decreases in optimization.
基金the National Natural Science Foundation of China(60175029).
文摘The paper presents the design of walking leg for bionics crab-like robot, which is driven with micro servo motor. The kinematic characteristics of the bionics machine are analysed for optimized structure parameters, which has been used in the robot design. A three closed loop motor control system structure for joint driver is also given, as well as the multi-joint driving system for walking robot leg.
