高精度数控机床直线电机的改进型自抗扰控制研究

Improved ADRC control strategy of linear motor for high precision NC machine

针对高精度数控机床伺服系统中,直线电机对扰动量高度敏感而影响系统稳态特性和控制精度的问题,提出了一种改进型永磁同步直线电机(PMLSM)自抗扰控制(ADRC)策略。将新型非线性函数引入扩张状态观测器,克服了传统型ADRC扩张状态观测器中非线性函数的不平滑性,并对系统总扰动进行了估算,并给予实时动态补偿;采用比例微分器代替非线性反馈控制规律,降低了系统参数调节的难度;利用Matlab对基于改进型ADRC控制策略的PMLSM调速控制系统进行了仿真,针对系统的空载启动响应特性和突加负载扰动对系统稳态性能的影响进行了测试。研究结果表明:与传统型ADRC控制策略相比,改进型ADRC控制策略具有更好的负载扰动抑制力和更小的超调量;系统控制精度得到提升。

Permanent magnet synchronous motors are suitable for direct diving of high precision numerically controlled servo systems. However, the high sensitivity of disturbance influence the position accuracy. Aiming at the problem, an improved active disturbance rejection control strategy of permanent magnet linear synchronous motors was proposed. A new non-linear function was introduced into the extended state observer to overcome the rough of non-linear function in extended state observer of conventional ADRC. By using the extended state observer of improved ADRC, the total disturbance of the system was estimated for real-time dynamic compensation. The proportional differentiator was used to replace the nonlinear state error feedback(NLSEF), and the difficulty of system parameter adjustment was reduced. The Matlab was used to simulate PMLSM speed control system based on the improved ADRC control strategy, and the effects of system’s no-load start response characteristics and suddenly-applied load disturbances on the steady-state performance of the system were tested. The results indicate that the improved ADRC strategy has better load disturbance rejection and smaller overshoot than the traditional ADRC control strategy. It can make the system has a good control accuracy.