Second-order system´s velocity feedback gain control based on PID variable damping ratio controller

Generally, in order to improve dynamic performance, second-order systems generally decrease oscillation and overshoot of output response by increasing equivalent damping ratio with velocity feedback. But output response will be dull and system´s speediness property will be worse because of damping ratio´s increment. Variable damping ratio control by fuzzy adaptive PID may adjust system´s damping ratio in real-time on line on the base of output response´s different phases, so improve system´s dynamic property. It is proposed variable damping though establishing PID´ s three parameters´ fuzzy logic control rules based on property of PID control and fuzzy logic control. Simulation results verify that the method is feasible, dynamic property´s improvement is prominent, and disturbance rejection property and robust is excellent.