Dynamics and Control of Nano-Motion Mechanisms

本研究的目标是实现纳米级定位精度和毫米级定位范围的运动机构。本研究计画包含三个主题：（1）奈米运动机构动力学、（2）冗余度机构控制、（3）精密非接触式磁力驱动器。(1)纳米级运动机构动力学实验研究了精密机器人谐波减速器和步进电机气浮丝杠机构在亚微米级到毫米级几个运动范围内的动力学特性。这两种机制都表现出宏观动力学和微观动力学，取决于移动范围。(2)余度机构的控制从理论和实验两方面研究了余度二级定位系统的最佳控制器。两级定位系统包括作为粗动机构的滚珠丝杠和直流电机，以及作为微动机构的PZT致动器和弹性铰链机构。系统采用PID、最优状态反馈、H_<inf>∞、滑模、模糊和神经控制器。分析了台阶高度、工作台质量和恒载荷变化对定位性能的影响。模糊控制器和神经控制器表现出最好的鲁棒性在七个控制器。(3)研究了采用电磁作动器的无位置传感器控制系统的定位精度。两种类型的位移估计器使用的观察员或磁通量传感器进行了测试。估计器的位移分辨率为0.1 - 0.15 μm。

The aim of this research is to realize motion mechanisms with not only nanometer positioning resolution but also millimeter positioning range. This research project consists of three subjects : (1) Dynamics of Nano-motion Mechanisms, (2) Control of Redundant Mechanism, and (3) Precision and Non-contact Magnetic Actuators.(1) Dynamics of Nano-motion Mechanisms Dynamic characteristics of a harmonic speed reducer for precision robots and an air bearing lead screw mechanism for steppers are experimentally examined within several moving ranges from sub-micrometer to millimeter orders. Both the mechanisms show macro-dynamics and microdynamics depending on the moving ranges.(2) Control of Redundant Mechanism The most suitable controller for redundant two-stage positioning system is theoretically and experimentally examined. The two-stage positioning system includes a ball lead screw and a DC motor as a coarse motion mechanism, and a PZT actuator and an elastic hinge mechanism as a fine motion mechanism. PID, optimal state feed back, H_<inf>, sliding mode, fuzzy and neural controller are applied to the system. Effect of step height, the table mass and constant load changes on the positioning performances are evaluated. The fuzzy and neural controllers show the best robustness in the seven controllers.(3) Precision and Non-contact Magnetic Actuators Positioning accuracies of sensorless control system using electromagnetic actuators are examined. Two types of displacement estimators using an observer or a magnetic flux sensor are tested. The displacement resolutions of the estimators are 0.1 - 0.15 μm.