Design Of The Power System Of Wearable And Flexible Lower-limb Exoskeleton

This paper proposes the power system of wearable and flexible lower-limb exoskeleton combining the pneumatic artificial muscle(PAM)and flexible wearable structure based on the study of traditional exoskeleton,and provides a complete control system solution.It mainly focuses on the kinematics and dynamics of lower limbs of the human body,the structure and characteristics of the PAM,the structure and analysis of the flexible lower-limb exoskeleton,the design of the control system and relevant experiments which realize good trajectory-tracking and torque-control performance.The exoskeleton device has light weight,high power-mass ratio and good flexibility so that it is easy to wear without discomfort or extra load and particularly suitable for assisting semi-disabled walking,lower-limb injured rehabilitation and other medical fields.In this paper,an effective method for calculating driving torque is found based on the motion measurement system and Lagrange equation.Then,it introduces the structural principle,production method,using problem,static model and experimental characteristics of the improved pneumatic artificial muscle based on the McKibben principle.A wearable and flexible lower-limb exoskeleton is designed and researched on the force analysis,motion modeling and parameter relationship,which is used to obtain the effective assisting torque.Meanwhile,the complete solution of the exoskeleton control system is provided.Hardware platform mainly includes the air pressure circuit composed of the air source,solenoid valves and PAMs,and the control circuit composed of the central controller and communication sensor elements.Software platform contains lower computer programs with functions of data communication,data acquisition,PWM signal generation and FSPID control,and the host computer programs with functions of serial data acquisition,data display and advanced control.In addition,the performance of the trajectory tracking based on the pose data and that of the torque control based on the pressure data are also verified by the experimental studies while the assisting effects on the lower limbs are tested by collecting EMG signal.The work of this paper provides a basic solution for the realization of the power system of wearable and flexible lower-limb exoskeleton,which lays the theoretical and experimental foundation for further in-depth study.