Research On High-speed And High-precision Motion Control Method Based On Low-damping Piezoelectric Nano-positioning Stage

With the rise and development of nanotechnology,the precision positioning system with piezoelectric nano-positioning stage as the core component has been widely used in high-ranking manufacturing equipment such as atomic force microscopes,grating engraving machines,and ultra-precision processing machine tools.The piezoelectric nano-positioning stage has the advantages of high resolution,fast response,compact structure,no motion friction,no lubrication and so on.It can provide nano precision motion positioning for semiconductor processing,ultra-precision manufacturing,biological manufacturing,nano detection and other fields.In recent years,with the expansion of the application of high-speed and highprecision precision manufacturing technology,the motion speed and positioning accuracy of piezoelectric nano-positioning stage have become increasingly demanding.However,the hysteretic nonlinearity of the piezoelectric actuator inside the stage and the low gain margin caused by the low damping vibration characteristics of the flexible mechanism limit the further improvement of piezoelectric nano-positioning stage motion speed and positioning accuracy.Therefore,the system nonlinearity and lowdamping vibration characteristics must be solved to achieve high-speed and highprecision motion positioning of the piezoelectric nano-positioning stage.This paper takes piezoelectric nano-positioning stage as the research object,and focuses on the research of compound control method that can suppress the vibration characteristics of the system and compensate the hysteresis nonlinearity to improve the system motion accuracy and speed.Firstly,according to the relationship between the hardware circuit and the mechanical dynamic characteristics of the piezoelectric nano-positioning stage,the electromechanical coupling model is built.The linear dynamic model of piezoelectric nano-positioning stage is obtained by parameter identification experiments,which provides the system model foundation for the follow-up research and application of piezoelectric nano-positioning stage control algorithm.Secondly,for the problem of low damping vibration limiting system positioning speed and accuracy,this paper does in-depth research based on input shaping technology,in order to explore more effective vibration suppression methods for piezoelectric nano-positioning stage.In this paper,the internal mechanism and shaping process of input shaping technology to suppress the low damping vibration are analyzed from the perspective of time domain and complex domain,respectively.Under openloop control,the effectiveness of the input shaping technology to suppress the vibration of piezoelectric nano-positioning stage is verified by simulation experiments.On the other hand,the effectiveness of the combined control method of out-loop input shaping for combined integral feedback control is explored in this paper.Compared with the traditional integral control,the compound control method mentioned in this paper can effectively eliminate the system ringing caused by the high feedback gain,so that the system can achieve a faster response speed with a higher feedback gain under the condition of maintaining a certain steady-state accuracy.In order to improve the low gain margin caused by the low damping vibration characteristics of the system,this paper proposes a composite active damping control method combining IRC controller,input shaper and PI feedback controller.In this paper,the advantages and disadvantages of inside-loop input shaping and IRC integral resonance controller are analyzed,and the relationship between them is explored.The damping effect of IRC can effectively alleviate the potential system instability caused by inside-loop input shaping,while inside-loop input shaping can enhance the damping effect of IRC controller.The effectiveness of the composite active damping control method in improving the motion speed and accuracy of piezoelectric nano-positioning stage is verified through a comparative experiment.The experimental results show that,compared with the traditional PI control,the composite active damping control can increase the system bandwidth by 8 times and the hysteresis error by 12 times.