宏/微结合双驱动进给控制系统的建模与仿真研究

Modeling and Simulation of Macro/micro Feed Drive Control System

采用宏/微结合双驱动进给系统能使系统在大行程范围内具有较高的定位精度。本文设计的宏/微结合双驱动进给系统,由交流伺服电机驱动滚珠丝杠作为宏动机构,压电陶瓷驱动柔性铰链工作台作为微动机构。分别对宏动机构和微动机构进行了数学建模。采用双伺服环控制策略,由宏动机构跟踪输入信号,由精密光栅尺检测宏动机构的实际位移进行反馈构成内伺服环;微动机构将宏动机构的跟踪误差作为输入信号,实时进行补偿,构成外伺服环,实现了宏/微结合双驱动进给系统的连续跟踪控制。最后进行了仿真研究,仿真结果表明跟踪幅值为1mm频率为0.4Hz的正弦曲线,采用宏/微结合双驱动进给系统比只采用宏动机构跟踪误差由±1.6μm减小到了±6nm。

Macro/micro feed drive system has a long stroke with ultra precision. The combined system including a macro stage and a micro stage is designed. A ball screw based on servo motor is used as the macro stage and a piezoelectric actuator is used as the micro stage. Dual-servo control strategy is implemented. The macro stage tracks input signal, actual displacement is measured by linear encoder as inner servo loop. The tracking error of macro stage is the input signal of micro stage to compensate as outer servo loop. The method realizes continual tracking control of macro/micro feeding system. Simulation was implemented finally. In the case of command input of a 1mm amplitude and 0.4Hz sinusoidal frequency, the tracking error is reduced from ±1.6μm for only macro stage to ±6nm for macro/micro feed drive system.