A Type II Fuzzy PID Controller for Lower Limb Rehabilitation Exoskeleton Robot

Official statistics show that the number of stroke patients in China has exceeded 28 million and is growing rapidly. The loss of walking ability of stroke patients increases the burden of family and society, and the demand for rehabilitation training increases. Exoskeleton robot-assisted gait training has been proved to provide effective help in rehabilitation training. However, the current exoskeleton control system on the market has poor stability and is difficult to deal with nonlinear problems. Based on this, a design method of type II fuzzy PID controller is proposed in this paper to solve the problem of poor stability of lower limb exoskeleton. The classical PID control algorithm and fuzzy control algorithm are combined, and the proportional, integral and differential parameters of PID control algorithm are adjusted adaptively by fuzzy rules. The controller model was built based on MATLAB/simulink for gait simulation. The experimental results show that the designed type II fuzzy PID controller can control the joint Angle error within 0.1°, the trajectory tracking movement is smooth, the stability is strong, and the walking track of healthy people can be quickly tracked from 0s, which proves that the control method proposed in this paper has better stability, good trajectory tracking effect and high safety.