Research On High-precision Coordination Control For Multi-Permanent Magnet Linear Synchronous Motor Servo System

Nowadays,with the automation manufacturing equipments applied widely in industrial production,the requirement for multi-motor coordination motion has rapidly increased.For its fast speed,thrust output and high precision,the permanent magnet linear synchronous motor(PMLSM)is widely used in high-precision industrial machining and position coordination control fields.Multi-PMLSM coordination control application has become a research hotspot and will be more extensive in the future.However,the tracking accuracy of single PMLSM and the synergistic accuracy of multi-PMLSM play an important role in the coordination performance of multi-PMLSM servo system.In this case,the high-precision control of single PMLSM and the coordination control strategy of multi-PMLSM have been researched and designed.The main research work is listed as below:1)Since the traditional proportional integral differential(PID)controller can’t satisfy with the control requirement when confronted to the control target like PMLSM with the characteristics of nonlinear,time variant and strong coupled,the control result is poor.Variable structure control is introduced into high-precision control of single PMLSM.Variable structure control has the superiority for nonlinear system because of its strong robustness and selfadjustment against un-modeled uncertainties and load disturbances.In this case,a sliding mode controller based on the variable exponential approach law is adopted in this paper to enhance the tracking accuracy of single PMLSM servo system,so that a high performance of coordination motion can be laid foundation for multi-PMLSM servo system.2)Since the adjacent cross-coupled controller is unable to change the gain compensation based on the states of motor operation,it will inevitably weaken the coordinated control performance.In this case,a variable-gain adjacent cross-coupled control strategy is adopted in this paper.The motor state of each PMLSM can be detected through system identification technology in real time.According to the motor states of the PMLSMs based on the system identification technique,a fuzzy position control algorithm is implemented for regulating the gain compensation.So the consistent stable tracking and coordination capability are subsequently maintained even with the existence of system uncertainties and load disturbances.3)Based on three-PMLSM servo system,the coordination control strategy is conducted on the MATLAB/Simulink environment and the control board of RT-LAB.It is proved from the experimental results that,compared with fixed-gain adjacent cross-coupled control scheme,the proposed controller keeps a stable tracking and coordination capability,under both no load and time-varying load conditions.For the variable-gain adjacent cross-coupled control,a steady-state tracking error and a steady-state synergistic error within 7μm and 8μm can be achieved,respectively.The experimental results show that the control strategy is valid.