Comparative Analysis of Conventional PID and Adaptive Control For Upper Limb Rehabilitation Robot

Abstract

A human muscle possesses the characteristics of recovering itself from any kind of stroke-effect disability or spasm if it keeps on repeating certain movements along a certain path. Rehabilitation robots have been recognized by researchers as one of the best techniques for the rehabilitation of impaired limbs. In this paper, a single degree of freedom rehabilitation robot has been developed and its movement has been controlled by using PID and adaptive control techniques. Accuracy in position control and stability of the system are two prime aspects of rehabilitation which one keeps in mind while designing a recovery device. These two aspects have been analyzed by using PID (Proportional Integral Derivative) and adaptive control algorithms under perturbed conditions. This analysis was carried out to learn which control algorithm is better suited for upper limb rehabilitation robots if there is some sort of external disturbance or a muscle stiffness is introduced to the robot in the form of load torque, which varies from patient to patient. The results prove that the proposed adaptive control technique is able to deal with unsettling conditions and perform the operation in a better way than conventional controllers.