Dual-Mode Control of Rehabilitation Mechanical Leg Based on Kinematic Modeling

Accurate mathematical models of lower limb rehabilitation robots are often difficult to obtain, which will affect their controllability. In this paper, a new exoskeleton robot is designed, and kinematics analysis of the rehabilitation mechanical leg is carried out. And dual-mode control, PID-fuzzy parallel control, is used in passive rehabilitation training. By comparing the angle error with the angle error threshold, the controller automatically switches between the two control modes to achieve the control purpose. Under the condition of no load, experiments were carried out on rehabilitation mechanical leg. The experimental results showed that the dual-mode control can reach the steady state faster than the classical PID control by about 3.2%, and the steady-state error of about 4.8% was reduced compared to the fuzzy control.