Fuzzy-PID Compound Control for Ultra-Precision Worktable

It is difficult to establish mathematical mode for ultra-precision worktable control system, because there are several disadvantages in the system, such as varying as time, nonlinear and so on. Fuzzy control has good robustness and other advantage, such as it need not establish the mathematical mode of controlled system, but steady state precision is bad. So a new control method which combined fuzzy controller with PID controller was proposed. Because different control schemes are used in different period in whole control process, the controller has inherited character of PID control, in which there are no static error and good static stability, and character of fuzzy control, in which there are strong compatibility and good dynamic property. Simultaneously, it gets rid of the disadvantages of them. Simulation experiment for ultra precision worktable control system has been carried on by Matlab software. PID control and fuzzy-PID control have been compared. Simulation results can prove that fuzzy- PID control can achieve better results. It was an efficient control method for the ultra-precision worktable.