Study On Robust Control Strategy Of Permanent Magnent Linear Servo System Based On Feedback Linearization

When permanent magnet linear synchronous motor (PMLSM) drives directly numerically- controlled machine tools, because of the break of permanent magnet linear motor armature iron core and discontinuity of stator winding, there are some uncertainties as end effect, parameter perturbations and nonlinear etc. At the same time, the load disturbance acts on the motor directly without buffering, the system's uncertainties is exacerbated further and increases difficulties of control. Therefore, this paper studies on permanent magnet linear servo system based on feedback linearization and robust control strategy.The control of PMLSM drives in the high- speeding and high-precision is not aneasy task, due to their no linearity and coupling. In this paper, state feedback linearization and input-output decoupling linearization of differential geometry are analyzed and compared systematically, and obtains nonlinear system's state feedback linearization control law by input-output decoupling feedback linearization method based on non-linear dynamic mathematical model of permanent magnet linear synchronous motor, and acquires input-output linearization model of permanent magnet linear synchronous motor through the coordinate transformation. It realizes linearization and decoupling for permanent magnet linear servo system.System's state-space model is established based on linear model, and the control problem of linear model can be boiled down to the standard H_∞control problem. Using H_∞robust control theory, treatment method based on the Riccati inequality for positive definite solution of Riccati inequalities, and obtains H_∞robust controller. It can improve the velocity and accuracy of the speed-tracking under the condition which guaranteed the stability of the whole closed Loop system. Finally, to verify the effectiveness of the algorithm, contrasted with PMLSM based on PI controller, simulated in two cases(no destabilizations, destabilizations), the MATLAB simulated results show that the robust control method based on feedback linearization of the system has good robustness, fast response characteristic, and rejection ability of the large disturbance.