Development of MAGLEV micro hand for assembly and machining

微电机和微机械部件近年来在微机械和生物领域得到了发展，其中一些已经进入市场，而传感器和处理器已经小型化。因此，具有高水平功能的微机械系统的制造在原理上是可能的。然而，传统的微机械生产是在显微镜下使用微操作器完成的，缺乏自主性。本课题的研究目的是研制一种用于灵巧装配和加工的微操作手。对于灵巧的操作，力控制是有效的。本研究主要针对微操作手的机构与控制进行探讨。手的设计包含以下重要特征。首先，采用磁悬浮技术，实现力控制，而不使用力传感器。第二，每个手指被约束到一个平行运动机构。该机构适合于机械加工，因为附接到指状物的刀具的取向保持恒定，并且该机构本身可以在机械加工时抵抗大的反作用扭矩。第三，手由具有三个自由度的两个手指组成，因此它可以应用于包括装配和加工在内的各种任务。在控制方面，设计了一个主从式协调控制系统，其中主指采用新设计的PID扰动观测器进行位置控制，而从指采用PD阻抗控制进行力控制，并研制了一个由并联机构组成的实验微操作手。用于直接位置测量的激光位移传感器和用于直接驱动的新设计的电磁致动器。利用该机械手成功地完成了微拉深、微钻孔、孔内引线等多种微细加工任务，达到了本研究的目的。

Micro motors and micro mechanical parts have been developed recently in micro-machine and biological areas, and some of them are in market, while sensors and processors are already miniaturized. Therefore, manufacturing of micro machine systems with high level functions is possible in principle. However, conventional production of micro machines is done using micro manipulators under the microscope and lack in autonomy. Moreover it lacks in a capability of simple machining like drilling.The aim of our research is to develop a micro operation hand for dexterous assembly and machining. For dexterous operations, force control is effective. Mechanisms and controls of micro operation hands have been investigated in this research. The hand design contains significant features as follows. First, magnetically suspension technology is adopted to realize force control without using force sensors. Second, each finger is constrained to a parallel motion mechanism. This mechanism is suitable for machining, since the orientation of a cutter attached to the finger is kept constant and the mechanism itself can resist large reaction torques while machining. Third, the hand consists of two fingers with three degrees of freedom and thus it can be applied to various tasks including assembly and machining. Concerning the control, a master-slave coordinate control system has been designed, where the master finger is position controlled with a newly designed PID disturbance observer, while other slave finger is force controlled with a PD impedance control.An experimental micro operation hand was developed which consists of the parallel motion mechanisms, laser displacement sensors for direct position measurement and newly designed electro-magnetic actuators for direct actuation. Using this hand, various micro tasks such as micro drawing, micro drilling and wire in hole were successfully conducted and the goal of this research was achieved.