Research Of Sliding Mode Control Method Of Voice Coil Linear Motor

In recent years,the development level of precision positioning technology,to a certain extent,represents the scientific and technological strength of a country,and reflects the comprehensive national strength of a country.From aviation and aerospace to the small lithography industry,which is directly related to various chips,precision engineering technology plays an important role in them.Among many precision positioning platforms,the more difficult one is the ultra-precision positioning of the super-large scale movement platform with a certain load.The commonly used method of ultra-precision positioning is to achieve large-stroke millimeter positioning by excitation linear motor,and micro-nano positioning by voice coil motor with its unique performance.Thanks to the excellent dynamic and static performance,and it can achieve without mechanical structure of the reversing operation straight line or the movement characteristics of corner,driven by voice coil motor institutions often can largely avoid transmission driven mechanical wear and tear,and therefore the voice coil motor in a precision position servo,especially high frequency reciprocating motion precision machining occasions need short stroke has obvious advantages and broad prospects.In this paper,the precision positioning control of voice coil linear motor as the center,first of all,the research background and significance of voice coil linear motor and the development status of voice coil motor at home and abroad are briefly introduced,and then the development of modeling and control methods.In order to better establish the model of the voice coil linear motor and design the precise positioning control method,this paper has carried out the characteristics analysis of the maximum speed and maximum acceleration of the voice coil linear motor,as well as the nonlinear factors testing such as friction and hysteresis characteristics.According to the above results,the secondary factors are ignored.The model description of voice coil linear motor is divided into two parts.The first part is called the determination of nonlinear terms,which is reflected in the calculation of the equivalent control quantity of friction according to its mechanics knowledge.The second part is linear modeling.The mechanism model of voice coil motor is deduced according to Newton’s second law,and its parameters are identified according to least squares.The combination of the linear model and the nonlinear term lays a foundation for the theoretical design of the controller.The linear equivalent control term of the sliding mode controller is designed for the identified linear model of the voice coil motor,and the nonlinear equivalent control term of the sliding mode controller is designed according to the nonlinear term of the voice coil motor.In this paper,a parameter determination method of the sliding mode equivalent nonlinear control term is proposed according to the experimental method.In this paper,the stability of the controller is proved according to the Lie stability theory.The effectiveness of the proposed sliding mode controller is proved by simulation and experiment.Although the proposed sliding mode controller for voice coil motor in point to point control and 3 order S curve tracking control on the error within a certain range,but did not consider in addition to the friction of the nonlinear factors and other unmodeled factors,in order to realize the precision positioning of voice coil motor,this paper combines the sliding mode control and the immunity control,differential tracker with the extended state observer is introduced into sliding mode variable structure controller,the nonlinear processing factors as well as other unmodeled factors as interference,the system equivalent to the double integral type.In order to enhance the disturbance rejection performance of the control system and reduce the gain of the system,the extended state observer in the ADRC is improved by effective amplitude limiting,and the stability of the proposed extended state observer is proved.Finally,the effectiveness of the proposed sliding mode active disturbance rejection controller is proved by simulation and experiment.