Bio-inspired control of joint torque and knee stiffness in a robotic lower limb exoskeleton using a central pattern generator

Author(s):  
Stefan O. Schrade ◽  
Yannik Nager ◽  
Amy R. Wu ◽  
Roger Gassert ◽  
Auke Ijspeert
2019 ◽  
Vol 6 ◽  
Author(s):  
Rafael Mendoza-Crespo ◽  
Diego Torricelli ◽  
Joel Carlos Huegel ◽  
Jose Luis Gordillo ◽  
Jose Luis Pons ◽  
...  

2017 ◽  
Vol 2017 ◽  
pp. 1-20
Author(s):  
Michael Oluwatosin Ajayi ◽  
Karim Djouani ◽  
Yskandar Hamam

A bounded control strategy is employed for the rehabilitation and assistance of a patient with lower-limb disorder. Complete and partial lower-limb motor function disorders are considered. This application is centered on the knee and the ankle joint level, thereby considering a user in a sitting position. A high gain observer is used in the estimation of the angular position and angular velocities which is then applied to the estimation of the joint torques. The level of human contribution is feedback of a fraction of the estimated joint torque. This is utilised in order to meet the demands for a bounded human torque; that is, τh≤N2,n≤N1,n. The asymptotic stability of the bounded control law without human contribution and the convergence analysis of the high gain observer is verified using Lyapunov-based analysis. Simulations are performed to verify the proposed control law. Results obtained guarantee a fair trajectory tracking of the physiotherapist trajectory.


Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4037
Author(s):  
Junghwan Yun ◽  
Ohhyun Kang ◽  
Hyun-Min Joe

This paper proposes a device that can change the payload of an unpowered lower-limb exoskeleton supporting the weights of humans and loads. Our previous exoskeletons used a cam–follower structure with a spring applied to the hip joint. This exoskeleton showed satisfying performance within the payload; however, the performance decreased when the payload was exceeded. Therefore, a payload adjustment device that can adjust the wearer’s required torque by easily applying it to the cam–follower structure was developed. An exoskeleton dynamic equation that can calculate a person’s required joint torque given the required payload and the wearer’s posture was derived. This dynamic equation provides a guideline for designing a device that can adjust the allowable joint torque range of an unpowered exoskeleton. In the Adams simulation environment, the payload adjustment device is applied to the cam–follower structure to show that the payload of the exoskeleton can be changed. User convenience and mass production were taken into account in the design of this device. This payload adjustment device should flexibly change the payload of the level desired by the wearer because it can quickly change the payload of the exoskeleton.


2012 ◽  
Vol 468-471 ◽  
pp. 1710-1713
Author(s):  
Yan Li Geng ◽  
Peng Yang ◽  
Ling Ling Chen

Commercial transfemoral prostheses remain limited to energetically passive devices. Intelligent prostheses still do not replace the power generation capabilities of the missing limb. Active Transfemoral Prosthesis is designed to compensate the movements of transfemoral amputees. Base on the function and principle of huaman lower limb, Active transfemoral prosthesis is designed. Virtual prototype of active transfemoral prosthesis 3D model is built through Solidworks. A dynamical system is used to generate a position trajectory to control a linear motor replacing the missing joint. Hopf oscillator is used to construct a central pattern generator (CPG), which makes up the dynamical system.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
William Suliman ◽  
Chadi Albitar ◽  
Lama Hassan

In this paper, we propose a central pattern generator-based model to control the walking motion of a biped robot. The model independently controls the joint torque and joint stiffness in real time. Instead of the phase-dependent neural model used by Huang in 2014, we adopt the same structure for all the walking phases, reducing the number of connections between neurons. This reduction enables the employment of the particle swarm algorithm to find the optimal values of these parameters which lead to different solutions with different performance criteria. The simulation of the proposed method on a seven-link bipedal walking model gave a good performance in the range of walking speeds, which is referred to as versatility, and in walking pattern transition. The achieved walking gaits are 1-period cyclic motions for all the input control signals except for few gaits. Besides, these 1-period cyclic motions have a good local and global stability. Finally, we expanded our neural model by adding connections that work only when the robot walks on uneven terrains, which improved the robot’s performance against this kind of perturbation.


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