Control of piezoelectric ceramic actuator via dynamic fuzzy system model

As the nonlinear hysteresis characteristic of a Piezoelectric Ceramic Actuator(PZT) has a big impact on periodic ultra-precise tracking accuracy, this paper investigates a methodology which combines the Dynamic Fuzzy System(DFS) feed-forward based on Takagi-Sugeno(T-S) fuzzy rule with the PI control. The identification methods of DFS antecedent and consequent structures are introduced. Then, DFS feed-forward with PI control strategy of periodic trajectory tracking is proposed according to theories of direct inverse model control and iterative learning control. Finally, the tracking control experiment is performed on a 20Hz triangular trajectory and a sinusoidal desired trajectory. Experimental results indicate that the proposed control method can achieve 0.25% and 0.27% maximum tracking errors for triangular and sinusoidal trajectories, which are 52 and 64 times as accurate as that of PI control. Moreover, the maximum absolute tracking errors have been reduced to 5.1 nm and 5.5 nm, respectively. It concludes that the methodology can be easily implemented and has high periodic trajectory tracking accuracy.