Speed Control System for Brushless DC Motor used in Isokinetic Exercise

Isokinetic exercise is the most effective way for rehabilitation and muscle strength enhancement which needs the isokinetic dynamometer to provide the equipment support. As a human-machine cooperative equipment, stability and robustness performances are significant for motor controller. In this paper, brushless dc motor (BLDCM) system is discussed and its mathematical model is built. Fuzzy PID controller which includes conventional proportional-integral-derivative (PID) controller and fuzzy controller becomes an effective and self-tuning controller to realize isokinetic control under the irregular load torque. The model of BLDCM and fuzzy PID controller are built in the environment of MATLAB/Simulink to verify the response of the whole system. Reference speed and load torque are the input parameters and the result showed that the designed BLDCM controller is effective and stabilized under disturbance.