Research On Hysteresis Modeling And Control Of Piezoelectric Actuator For Fast Steering Mirror

Fast steering mirror is an important component parts in inter-satellite laser communication system. It is a protection to achieve acquisition, pointing and tracking in inter-satellite laser communication system. The piezoelectric ceramic actuator, which has the advantages of large output torque, high precision, small size, stiffness, fast response and low heat, is the ideal device for driving fast steering mirror. However, the piezoelectric ceramic actuator exists hysteresis and creep nonlinear phenomena, which have a bad effect on the positioning performance. The hysteresis characteristics is the most serious factor. So how to solve the problem of hysteresis is the current hot topic of academia. To reduce the impact on the hysteresis of piezoelectric ceramic actuator positioning performance and improve its performance, this paper studied the theory and critical techniques of piezoelectric ceramic actuator deeply, revealed the causes of the hysteresis, established the hysteresis mathematical model, and proposed a control algorithm to reduce the impact of hysteresis and verified the validity of the model and algorithm of the system.First, by analyzing the hysteresis characteristics of piezoelectric ceramic actuator, this paper proposed an improved Prandtl-Ishlinskii(PI) model which can describe hysteresis characteristics, identified the analytical solution in improved PI model by least squares method and verified the model by establishing experimental system. The results of experimental show that the improved PI model and parameter identification base on least square method can effectively describe the piezoelectric ceramic actuator hysteresis characteristics, and the model error is within 1%. Besides, improved PI model is far superior to the traditional PI model in time complexity, which effectively improve the bandwidth of the control system and can easily applied to practical engineering.Secondly, this paper proposed a linearization control method base on improved PI model of piezoelectric ceramic actuator, obtained the inverse hysteresis model by improved PI mathematical model and transformed expected signal to control signal though inverse feedforward compensation to obtain a nearly linear system. The model output and real system output of feedforward linearization method was validated by experiments. The results show that linearity error of feedforward model control method is 0.9% and the linearity of the piezoelectric ceramic meet precise control requirements.Finally, in order to improve the dynamic performance of the system and to control the fast steering mirror accurately and quickly, this paper designed a complex control method based on improved PI inverse model and robust control, and compared the tracking performance of complex control method and feedback control method under different frequencies through simulation and experimental. Experimental results show that the complex control method can significantly improve the accuracy of positioning control, and has a high robustness. When tracking 2Hz sinusoidal signal, the system’s maximum error is 2.8μrad and mean square error is 0.68μrad, when tracking sinusoidal signal of 100 Hz, the system’s maximum error between 16μrad and mean square error of 8.8 μrad.This paper studied piezoceramic actuator hysteresis model and its system’s linearization and control method for a piezoelectric ceramic piezoelectric actuator, and laid a theoretical foundation for piezoelectric ceramic piezoelectric actuator’s fast, precise positioning applications in satellite laser communication system.