Application of the Udwadia-Kalaba approach to tracking control of lower limb rehabilitation robot

This paper presents an explicit dynamic equation of motion of lower limb rehabilitation robot in reference to Udwadia-Kalaba approach and conducts experiment and simulation which verify the effectiveness and availability of the novel approach. Fundamental equation of lower limb rehabilitation robot which considers the resistance of human muscles is deduced according to Udwadia-Kalaba approach. The angle trajectories of hip and knee joints of a healthy person are explicitly obtained by A Wearable Human Posture Detection System (WHPDS) based on MEMS Inertial Sensors and used to as servo constraints of the robot. The control torques desired to drive the rehabilitation robot along the target trajectories accurately are solved. No auxiliary variables are used in the modeling or analysis. It can be concluded from the simulation results that the proposed control approach is a very useful optimizing method for the lower limb rehabilitation robot with its advantages of simplicity, validity, and accuracy.