A nonlinear PID controller with tracking differentiator applying in BLDCM servo system

The BLDCM servo system always works under the complicated conditions such as variable parameters and load, its dynamical performance is difficult to be guaranteed. A nonlinear PID (NLPID) controller is designed in this paper. The parameters of PID can be changed according to the principle of nonlinear functions of the error information so make the system has an improved dynamical performance. Tracking differentiator (TD) has filtering properties and can overcome the nonlinearities caused by disturbances and noises. The tracking signal and the differential signal can be achieved by TD. The NLPID controller doesn't rely on the plant model and can make self-adjustment according to the error information. Simulation results show that short response time, small overshoot, ability of anti-disturbance and anti-noise can be achieved by the NLPID controller.