基于滑模观测器的直线伺服系统反馈线性化速度跟踪控制

Feedback linearization speed-tracking control of linear servo system based on sliding mode observer

在许多高速、高精的直线伺服系统中,要求能实现对速度的快速精确跟踪,但其模型的非线性和变量间的耦合给控制带来难度.对高速、高精速度跟踪控制中,电流和速度的变化过程在时间尺度上相对接近,不能简单地采用磁场定向矢量控制方法实现静态解耦,否则电流和速度间的非线性耦合将破坏速度跟踪品质.采用状态反馈线性化方法来实现永磁直线同步电动机(PMLSM)模型的精确线性化和动态解耦.利用非线性坐标变换和非线性反馈将系统解耦成独立的线性电流子系统和速度子系统.通过扩展滑模观测器来实现对所需要的动子速度、加速度和负载扰动的鲁棒观测.并利用李雅普诺夫理论对由反馈线性化和滑模观测器构成的非线性闭环系统的稳定性进行了证明.仿真结果表明该方案使PMLSM伺服系统具有良好的鲁棒速度跟踪性能.

The rapid precision tracking of speed is required in many high speed and high precision linear servo systems,but it is difficult to control because of the nonlinearity of the system model and the coupling between the variables.The variable processes of the current and speed is relative propinquity in the time scale,therefore the magnetic field directional vector control method cannot simply be used for the static decoupling,otherwise the quality of speed tracking will be damaged by the nonlinear coupling between the current and speed.The feedback linearization method is used to achieve the precision linearization and dynamic decoupling of the permanent-magnet linear synchronous motor(PMLSM) servo system.The nonlinear coordinate commutation and nonlinear feedback are used for decoupling the servo to unattached linear current sub-system and speed sub-system.A sliding mode extended observer is designed to realize the robust observation of the speed,acceleration and unknown load resistance necessary for speed-tracking control.Furthermore,the stability of the speed-tracking control closed loop system constituted of feedback linearization control and sliding mode observer is analyzed using Lyapunov stability theory.Some simulation results show that this control scheme makes the PMLSM servo system have good robust speed-tracking performance.