传统控制器实现有摩擦系统的大行程纳米定位(英文)

Long-Stroke Nanometer Positioning of Frictional Table System by Conventional Controller

对于"伺服电机+滚珠丝杠"驱动机构,摩擦、饱和和高频振动等非线性因素是实现大行程无超调高精度点位(PTP)控制的主要障碍.针对这种驱动系统,在根据刚体动力学计算得到的线性传递函数的基础上,设计了高增益PID闭环控制系统和输入滤波器来实现大行程的纳米定位.配置闭环控制系统的极点为负实轴上的多重极点,避免了摩擦力补偿和双模控制策略的使用.为了避免驱动器饱和所导致的闭环系统响应超调现象,基于数字低通滤波器设计了闭环输入信号.实验结果表明,该定位系统可以实现大行程无超调纳米精度点位控制,10 nm^100mm定位响应的稳态误差不超过±5 nm.

For a DC-motor and ball-screw-drive table system, the nonlinearities such as friction, saturation and high frequency resonance are the major obstacles to the achievement of high-precision and long-stroke point-to-point （PTP） positioning without overshoot. Based on the transfer function obtained according to rigid body dynamics of the ball screw mechanism, a high gain PID controller and an input filter was designed to realize long-range nanometer positioning. Parameters of the closed-loop control system were calculated by multi-poles placement so that neither friction compensation nor dual-mode control strategy was necessary. The input signal of the closed-loop system was designed based on digital low-pass filter to avoid large overshoot due to the actuator saturation. Experimental and simulated results demonstrate that the proposed system can achieve long-stroke nanometer positioning without producing any large overshoot, with the steady-state error within ±5 nm in PTP positioning from 100 mm down to 10 nm.