关键词: 压电驱动器, 大位移, 迟滞, 非线性模型, 控制系统

Abstract: A piezoelectric linear actuator featuring low frequency, large displacement, and high-load characteristics was proposed, capable of operating in three modes to accommodate a variety of operational conditions. The working principle of the actuators and the displacement amplification under different loads were analyzed. For the hysteresis nonlinear phenomenon of the piezoelectric actuators, an improved hysteresis nonlinearity model was developed, which was based on PI and enhanced through a genetic algorithm optimized backpropagation neural network(GA-BP). A GA-BP feedforward fuzzy self-tuning PID compound control system was established, and the hysteresis nonlinear compensation experiments of the actuators were carried out. Results show that the maximum output displacement of the actuators is as 558.3 μm when two piezoelectric stacks are working simultaneously, and the maximum relative error of trajectory tracking is as 0.0573 μm under sinusoidal signals. The implementation of the improved control strategy effectively enhances the performance of the systems, resulting in a trajectory tracking control accuracy of up to 97%, a reduction of the delay time to less than 2 ms, and the ability to realize the control response within 60 ms. This strategy accelerates the systems response speed, and reduces the steady-state errors to less than 0.09%, demonstrating the capability for rapid responses and minimal steady-state errors.

Key words: piezoelectric actuator, large displacement, hysteresis, nonlinear model, control system