Robust Control System Design Of A Overlapped Winding Type PMDC Maglev Planar Motor

Maglev planar motor achieve mover’s non-contact stable suspension and ultra-precision flatdrive through the interaction electromagnetic forces between the mover and the stator, is thedrive component of the next generation ultra-precision machining instrument. So the in-depthstudy of Maglev planar motor is extremely important for the development of next generation ofultra-precision machining technology. In this paper, a five degrees of freedom overlappedwinding type PMDC maglev planar motor is proposed, and a theoretical model of gap-voltage isbuilt through analyses of its magnetic field. Using this model, a wide range of linearization androbust controller design based on H∞control theory are studied. Following are the maincontents:1The structure and the multi-DOF operation principle of the new maglev planar motor areintroduced. The magnetic field of maglev planar motor is theoretical analyzed by Fourier seriesmethod and equivalent surface current method, and then an accurate and feasible affine nonlinearmathematical model of maglev system is built, through parameter identification. At last theaccuracy of magnetic field analytical results and the built model are verified by experimental.2The voltage control model of maglev system is converted to a wide range of completelyaccurate feedback linearization model, using differential geometric method. With the complexityimplementation analysis of the voltage model’s precise feedback linearization, a current controlmodel and its completely accurate feedback linearization is introduced and then the accuracy oflinearization model is verified through simulation.3The uncertainty in the maglev planar motor is analyzed and attributed to mixed sensitivityproblem, and then with choose weight functions, the robust controller is solved using loopshaping method. Through simulation finding that the robust controller solved with generallyselect weight function method is not robust or even unstable when it is used in a feedbacklinearization system. So the weight function select method is improved and the corresponding robust controller is solved. The maglev robust control system model is built usingMATLAB/SIMULINK software, to simulate its dynamic effect and robustness, and its greatcontrol performance is verified through comparing with the PID control system simulationresults.4Using the MATLAB/RTW/xPC as Digital Controller, a levitation control systemexperimental platform is built. The control accuracy, wide range of precise control, dynamicperformance and tracking performance of the designed robust controller are verified based on theexperimental platform of RTW and the more excellent control performance of the robustcontroller is proved by comparing its experimental results with the PID control system.