| The dissertation is devoted to the Fuzzy-PID control system for the suspensionsubsystem of the magnetic levitation permanent magnet linear motor, which is supplied bythe National Natural Science Foundation project:“Study on the direct magnetic levitationpermanent magnet linear motor of CNC machine tools and its servo control system（projectapproval number:50975181）”. The main research contents of the thesis are as follows:(1) The special structure and operation principles of the suspension subsystem of themagnetic levitation permanent magnet linear motor are studied. Because the magneticlevitation permanent magnet linear motor has double windings, vector control is used toachieve the decoupling of two sets of windings. Then, the suspension subsystem can becontrolled independently. After researching on mathematical models of the ordinary linearmotor, voltage equation, flux equation, dynamic equation and suspending power equationof the levitation subsystem of the linear motor can be obtained which are important fordesign of the control system of the suspension subsystem.(2) With nonlinear mathematical model, the suspension subsystem of the magneticlevitation permanent magnet linear motor is nonlinear and has external disturbanceuncertainty. By researching on PID control algorithm and fuzzy control algorithm andanalyzing the advantages and disadvantages from PID and fuzzy algorithm, Fuzzy-PIDcontrol algorithm is proposed which is used in displacement loop of the suspensionsubsystem to meet high accuracy and high robustness control requirements of thesuspension subsystem. Finally, in order to verify the effectiveness of the fuzzy PID controlsystem, Matlab/Simulink simulation software is used for simulating analysis of thesuspension subsystem. (3) Control system design for the suspension subsystem of the magnetic levitationpermanent magnet linear motor. Hardware design include control circuit which is based onDSP28335, main circuit which is mainly composed by IPM PM15RSH120, drive circuit ofIPM and suspension winding current and suspended height detection circuit, etc; Softwaredesign include main program, timer underflow interrupt service subprogram which includethe current sampling, coordinate transformation of sampling current, suspension heightsampling and height adjustment control algorithm, etc and capture interruption servicesubprogram which is used to calculate pole position by receiving and calculating signalsfrom linear grid ruler.(4) Experimental research for the magnetic levitation permanent magnet linear motorsuspension control system. In order to test the performance of the magnetic levitationpermanent magnet linear motor prototype, the harmonic of the back electromotive-forcewhich is measured from the motor suspension winding is compared with harmonic fromfinite element calculation. The experiment of the magnetic levitation subsystem heightdetection is designed to verify the effectiveness of suspension subsystem height detectioncircuit based on eddy current sensor. Finally, measure and analysis PWM signals waveformand signals waveform from the linear grid ruler. |
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