通过直线伺服鲁棒跟踪控制方法提高轮廓加工精度

为了减小零件加工的轮廓误差,提出了一种采用直线伺服驱动的零相位跟踪控制器(ZPETC)和干扰观测器 (DOB)相结合的鲁棒跟踪控制策略。零相位误差跟踪控制器作为前馈跟踪控制器,提高了快速性,使系统实现准确跟踪;基于干扰观测器的鲁棒反馈控制器补偿了外部扰动、未建模动态、系统参数变化和机械非线性等不确定因素,并根据预测到的干扰信息对各轴进行补偿以消除干扰对系统的影响,从而保证了系统的强鲁棒性能。仿真结果表明所提出的控制方案是有效的,既能实现完好跟踪,又有较强的鲁棒性能,从而提高了轮廓加工精度。

IMPROVING CONTOUR MACHINING PRECISION BY THE LINEAR SERVO ROBUST TRACKING CONTROL

To reduce the contour error of the part machine, for the linear servo drive system, a robust tracking control strategy based on combining zero phase error tracking control (ZPETC) with the disturbance observer (DOB) is proposed. The zero phase error tracking controller is designed to ensure that the system has fast tracking performance and implements exactly tracking; while the DOB can overcome the influences of the uncertainties of the parameters perturbation, the external load disturbances, unmodelled dynamic and mechanical nonlinearity etc. DOB can compensate for each axis according to predicted disturbance information to eliminate the influences of the disturbance to the system, thus the stability and robustness of the system are obtained. The simulation results show that the control scheme not only can enhance the fast tracking performance in the linear servo system, but also has a strong robustness to parametric variations and resistance disturbances. Therefore the contour error is reduced effectively, and the precision of the contour machining is improved greatly.