Vibration Suppression Of Micro-nano Positioning Device Based On Flexible Mechanism

Micro-nano positioning devices which have received continuous attention and emerge a large number of researches in recent years are the most important part to achieve precision manufacturing and precision measurement.They are widely used in semiconductor manufacturing and assembly,biomedicine,and precision optical measurement industries.Traditional positioning device,such as the piezoelectric actuator have a high resolution,but a short motion range for just around several hundred micrometers.The positioning device which based on magnetic levitation technology can realize high-speed and high-precision positioning motion,however,it's sensitive to load change due to the complex model.In this paper,a micro-nano positioning device which build by a guide using flexible mechanism,and a driver using voice coil motor to achieve a large-stroke,high-precision positioning motion.In response to the problems above,this paper conducts the following research:Firstly,“micro-nano positioning device and its servo control”,the basic characteristics of flexible mechanism and voice coil motor are analyzed,the basic performance test of the micro-nano positioning device including the mode,stiffness of the flexible mechanism and the force constant of the voice coil motor are completed,the mathematical model,frequency response and transfer function model of the micro-nano positioning device are obtained,the low damping characteristic is verified and a three-loop PID control strategy for positioning device is established based on dSPACE.Secondly,“vibration suppression algorithm based on positive velocity feedback”.In this paper,a PI controller was introduced to the position loop and a positive speed feedback(PVF)control scheme was used to do the vibration suppression by optimizing the controller parameters.The experiments show that this method can effectively improve the frequency response of the velocity loop,increase the system bandwidth,and realize the position servo control of the device.Thirdly,“a damper-based vibration suppression method to suppress the system vibration”.The voice coil motor has multiple windings and each one can be independently controlled.This paper using a single winding to generate the viscous damping force while other windings are used to drive the motor.The relationship between system stability and viscous damping coefficient is analyzed by mathematical approximation and discretization.Experiments show that by configuring a suitable damping coefficient,the system vibration can be suppressed and the steady-state position error can be reduced in the same time.Fourthly,“trajectory planning design based on combined trigonometric functions”.By combining the trigonometric functions between different amplitudes and different frequencies,a continuously differentiable trajectory curve is obtained to be used in motion process.The time and frequency domain characteristics of the trigonometric function trajectory under different combinations are analyzed.Through reasonable configuration parameters,guarantee the impact when motion starts or stops to be zero in the system to reducing the system vibration which caused by the input signal impact.Finally,the micro-nano positioning device and the high-speed high-precision linear motor are used as the control objects to compare and analyze the performance between the trigonometric function trajectory and the S-curve,respectively.And the simulations and experiments show that the trajectory based on the trigonometric function is continuous and smooth,its effect of reducing impact is obvious,especially in high-speed motor.