Modeling And Control Of The Precision Positioning System Of Macro/Micro Two-Stage Driving

With the rapid development of precision machining technology,microelectronic engineering,biological engineering and precision measurement,the requirement of precision positioning platform gradually improve which embodied in the higher precision and long stroke.Research of high precision and long stroke positioning platform has the important meaning and the actual demand.There are two kinds of single driven precision positioning stage: piezoelectric ceramic or voice coil motor as drive mechanism with high precision,fast response and short stroke,the positioning of the motor and roller screw combination way platform with long stroke and limited precision.In order to meet the positioning requirements of large travel and high precision,developed a bellows and two-stage driven by voice coil actuator high precision positioning platform with the idea of macro/micro two –stage driving.Firstly,put forward the entirety scheme of two-stage driven positioning stage and design the mechanical structure of the double stage drive platform.The positioning stage consist of macro platform driven by bellows and micro platform driven by voice coil motor.Puts forward the macro to micro two-stage driven control strategy,and the establishment of a macro to micro two-stage driving dynamics model.Secondly,analyze the bellows,the dynamic model of electric proportional valve and drive platform by studying the static characteristic of the bellows,established bellows driven macro mathematical model of the moving platform.Using the PID closed-loop control to achieve high precision positioning.Analyze the working principle of the voice coil motor,establish the mathematical model of voice coil motor for voice coil motor electric balance equation.Study the voice coil motor drive technology,and design the voice coil motor drives.Study the control strategy for micro platform,using the double closed loop control with feed-forward.In order to improve the position precision of the system,established the micro platform hysteresis model based on neural network,the simulation results show that the positioning accuracy of hysteresis model is better than PID.Finally,build the experiment platform test stage and design control strategy consist of up and down machine.PC using Lab VIEW design a friendly human-computer interaction interface,down-machine adopts STM32 to control system.At the middle of them,via a serial port communication to transmit.The experimental results show that the macro/micro two-stage driven positioning platform can achieve large stroke and high precision positioning requirements.