Comparison of PID and fuzzy logic controller for DC servo motor in the development of lower extremity exoskeleton for rehabilitation

Abstract

Impairment of motor function of the lower extremities is a common result of stroke or spinal cord injury due to the harm caused to the spinal column. Rehabilitation using a lower extremity exoskeleton for therapy purposes has been examined to improve motor function of the affected limb. PID controller is the most widely recognized types of feedback controller in control strategy. The simplicity and functionality of the PID controller made it a common controller in various applications. Many researchers have adopted the PID as the controller for their system and the exoskeleton manipulator for rehabilitation devices is a part of it. However, the conventional PID controller is not suitable when controlling a real-time system that needs fast response time with less overshoot due to the trial-error process. Thus, the Fuzzy Logic controller can be a solution to control the lower extremity exoskeleton in a real-time system. This paper shows the simulation of PID tuning (Ziegler Nichols and Cohen Coon) and Fuzzy Logic Control for DC Servo Motor by using Matlab/Simulink. A performance comparison between the PID tuned and Fuzzy Controller for DC servo motor was presented.