Study On Dynamical Model And Digital Control System Of Magnetic Levitation Nano-positioning Stage

With the rapid development of the manufacturing industry, the requirementfor the assembly accuracy is also rising. Traditional assembly methods canno longer meet the requirement of precision. Processing, manufacturing,measurement and assembling in nano size are the new direction of themanufacturing industry. So there is a need for a kind of Nano-positioning stagewhich can be used for the processing, manufacturing, measurement andassembling in nano size. Recent years, the study focuses on small size, highprecision and large travel of nanoscale positioning platform. Relative to thetechnology of the micron precision positioning platform, large stroke nanoprecision positioning platform is still in its infancy.This paper is to research a digital controller and a dynamical model ofa nano-positioning tage. The main research contents are as follows:(1) Structure and dynamical model of the two-dimensional stage withnano-scale percisionIn order to avoid the the Abbe s error of traditional structure of thetwo-dimensional positioning stage, common planar structure is introducedin the paper, which can avoid the Abbe s error effectively. This stage isdesigned to be an interlayers structure, thus the nolinear electromagneticforce can be linearized. The static and thermodynamics analysis is carriedout for the stage. Dynamical model proves that this interlayers structurecan simplify the controller of the system greatly.(2) Electromagnetic analysis of the stageThe "magnetic levitation technology plus linear motor" principle was usedfor the maglev stage in this paper. The horizontal driving force and levitationforce are generated by the interaction between the winding and permanent magnetof the linear motor, thus the non-contact drive without friction and wear wasachieved. In this paper, the analytical methods and the finite element methodswere used to analyse and calculate the Halbach permanent magnet array, thehorizontal driving force and the levitation force, thus the main designparameters of the stage were determined. (3) Control systems of the stageBased on the dynamical model of the nano two-dimensional stage, SVPWM spacevoltage vector technology and PWM control are used to finish the control ofthis nano two-dimensional stage. The all-digital control circuit of the maglevstage was manufactured with the DSP and FPGA platforms as the core unit. Thedesign of the power drive circuit, PWM control module of the DSP is done, andthe precision displacement feedback system based on QEP and laserinterferometer is accomplished.