大范围变载直驱系统的速度滑模控制与扰动补偿研究

Velocity Sliding Mode Control and Disturbance Compensation for a Large-scale Variable-load Direct-drive System

针对数控机床中大范围变载永磁同步直线电机直驱系统采用速度滑模控制策略时,出现滑模控制器中切换系数对系统的抗扰性和抖振相矛盾的问题,设计了一种带滑模负载观测器前馈补偿的新型速度滑模控制策略。该策略采用速度观测误差做闭环滑模扰动观测器,并将扰动观测值前馈补偿到速度环控制器的输出端,从而可以使速度滑模控制中切换系数较小的情况下有较强的抗扰性,同时达到削弱速度抖振的目的。仿真结果表明,所提出的策略在保证系统稳定的同时,提高了负载扰动时电磁推力的跟踪相应性能,削弱了系统抖振,因此该策略适用于机床大范围变载直驱系统的应用。

Aiming at the problem that the switching coefficient of sliding mode controller is contradictory to the disturbance and chattering of the system,a new speed sliding mode control strategy with sliding mode load observer feedforward compensation is designed for the large range variable load Permanent Magnet Linear Synchronous Motor direct drive system using the speed sliding mode control strategy in the NC machine tool.The method adopts the velocity observation error to do the closed-loop sliding mode perturbation observer,the feedback of the disturbance observation value is compensated to the output end of the speed loop controller,which can make the speed sliding mode control have strong immunity when the switching coefficient is small,and at the same time weaken the speed chattering.The simulation results show that the proposed strategy can improve the tracking performance of the electromagnetic thrust when the load is disturbed,and weaken the chattering of the system,so it is suitable for the application of the machine tool wide range variable load direct drive system.