Research On Key Technology Of Semi-active Controlled Intelligent Prosthesis

The research of intelligent prosthesis combined electronic, information, control, materials, bio-medical, mechanical and other technologies as one of the pioneering, interdisciplinary study. Mechanical design and control method of intelligent prosthesis knee joint of significant meanings to the study of intelligent prosthesis.This paper describes the design elements of intelligent prosthesis, gives the design scheme of intelligent prosthesis. Taking the instantaneous rotated center of the knee joint as optimized goal and referring the human knee size range, Using the genetic algorithm which has better global search performance to optimize four bar mechanism of knee joint, then the ideal size and structure of knee joint have been obtained. When selecting the driving device, structural characteristics of bionic legs confine the size and power consumption. These two aspects as well as the effect of computer controlling make magnetorheological damper to drive the knee joint. In order to get better control effect, based on damper's mechanical model to make experimental scheme and process parameter identification for the control.Dynamic model of prosthesis mechanism is more complex, usually the models are established for a rigid body based on the whole system hypothesis, there is a big difference between this point and the health of human body. The system identification technique of modern control theory could establish the system model without too much understanding of mechanism. During the system identification process, pretreat knee joint experimental input-output data firstly, and then based on priori knowledge choose several different types of models to identify system model. Type and model parameter identification are carried out at the same time. In the case of the same input, select the smallest difference with the actual output model as a result of identification. Finally, using genetic algorithm to optimize the three parameters of PID controller, and processing the following simulation of knee joint angle.