Fuzzy PID Controller Based On DSP And Its Application To Intelligent Artificial Legs

Intelligent artificial leg has been an interesting research project in the fields of robotics and biomedical engineering, its most excellent characteristics is that it can imitate the movement ways of human healthy legs and its walking speed can change naturally with the change of amputee's walking speed. The research on this project is of practical significance to improving the living situation and welfare benefits of amputees. For the past years, several intelligent artificial legs have been developed. But, the controller, which is used to control the opening of throttle of an air cylinder in these legs, is an open-loop system composed of a stepping motor, and has lower position precision. In this paper, we will design a closed-loop control system with position and velocity feedback and adopt fuzzy PID control strategy. The results of computer simulation and experiment on this control system indicate that the Intelligent artificial leg's fuzzy PID controller proposed here raises the intelligent behavior, robustness, response speed, and accuracy of the control system.First, we give introductions to the control principle of intelligent artificial legs and main characteristics of TMS320F240 digital signal processor (DSP), and then propose a system structure for Fuzzy PID controller based on TMS320F240. The result of computer simulation to this control system indicates that the design method proposed here is correct and can be used effectively to control the walking movements of intelligent artificial legs.