Research On Quasi Sliding Mode Control Of Powered Transfemoral Prosthesis

Compared with the conventional passive prosthesis,powered transfemoral prosthesis can provide appropriate assistance for the amputees and make them walk naturally as normal people.Therefore,the research of powered transfemoral prosthesis has important theoretical significance and application value.The main contents are as follows:Firstly,the motion data of different gait patterns are analyzed and a motion pattern recognition method based on the gyro sensor and plantar pressure sensor is proposed.The Adaboost algorithm is introduced into this field,which realize the real-time recognition of the level walking,stair ascent and stair descent with a high recognition rate.Secondly,in order to improve the performance of the powered transfemoral prosthesis,the mechanism of lower limb movement is analyzed on the basis of former dynamic modeling method.The dynamic model of the lower limb movement is obtained through the dynamic analysis of swing phase and stance phase respectively by the Lagrange method,which lays the foundation for the prothesis control.Thirdly,the quasi sliding mode control method is proposed to solve the problems of model error and disturbance.The controller for swing phase and stance phase is designed respectively and the stability of the algorithm is proved by the Lyapunov method.Finally,a walking simulation system of the amputees is designed based on the Solidworks,Adams,and Matlab.The simulation results show that the proposed quasi sliding mode controller can achieve the closed-loop control of the powered transfemoral prosthesis with strong robustness,and it is a effective method.