超精密加工伺服系统滑模控制技术研究

Study on Sliding Mode Control in Super-precision Machining Servo System

按超精密加工伺服系统原理建立的交流永磁同步电机伺服系统模型,其控制装置处理输入数控指令和检测系统反馈数据后,送伺服驱动单元数字控制板,经放大器控制电机运转。模型用带扰动观测器补偿的滑模变结构控制,对控制函数切换并受滑动模态控制。由伺服电机转子坐标系电压方程建立的伺服系统数学模型,以电机动态角度期望值和实际角度值描述角误差和角速误差。滑模控制器输入结构为滑模等效控制项、切换控制项、扰动前馈补偿项,其控制参数在线性切换函数中引入积分环节,通过滑模等效条件推导出等效控制,即可得出具有扰动补偿的控制模型。Matlab仿真表明对外在扰动有较强鲁棒性。

According to principle of the super-precision machining servo system, the model of servo system for AC permanent magnet synchronous motor was established. After control equipment processed NC instruction and feedback data of testing system, the data was sent to digital control plate of servo drive unit, and then the amplifier controlled motor running. Owing to applying the model of sliding mode variable-structure control that has compensation of disturbance monitor, switching control function was controlled by sliding mode. The math model of servo system was established with voltage equation in rotor coordinate system of motor, angle error and angle speed error was described with the expected value of dynamic angle and practical angle value. The input structure of sliding mode controller used as equivalent sliding mode control term, switching control term and disturbance feedback compensation term. In linear switching function, control parameter was entered to integrating factor, equivalent control was deduced according to equivalent condition, control model with disturbance compensation was obtained. Matlab simulation shows sliding mode control has nicer robustness.