压电驱动器的开闭环迭代学习控制

Abstract

As open-closed loop iterative learning control scheme can up the convergence and reduce the tracking error, this paper uses the scheme to improve high frequency trajectory tracking accuracy of a piezoelectric actuator(PZT). First, a discrete-time open-loop P-type with closed-loop PI-type iterative learning law was proposed and its convergence condition was given. Then, a discrete-time open-closed loop iterative learning controller was designed for the PZT system. Finally, as to 50 Hz and 25Hz+50Hz triangular desired trajectories with single and compound frequencies, the tracking control experiment was performed. Experimental results indicate that the proposed iterative learning controller can achieve 10.6 nm and 12.5 nm maximum tracking errors for the 2 kinds of trajectories, which are 96.25% and 95.62% less than that of the PID controller. It concludes that the proposed control scheme can be easily implemented and can obtain the high accuracy of trajectory tracking without precise hysteresis and PZT system models. It meets both the requirements of single and compound frequency trajectory tracking for high tracking accuracy.