Development of MAGLEV micro hand for assembly and machining

最近在微机械和生物领域开发了微型电机和微型机械部件，其中一些已经投入市场，而传感器和处理器已经小型化。因此，制造具有高级功能的微机械系统在原则上是可能的。然而，传统的微型机械生产是在显微镜下使用微型机械手完成的，缺乏自主性。此外，它缺乏钻孔等简单加工的能力。本课题的研究目的是开发一种用于灵巧装配和加工的微型操作手。对于灵巧的操作，力控制是有效的。本研究对微操作手的机理和控制进行了研究。手的设计包含以下重要的特点。首先，采用磁悬浮技术，在不使用力传感器的情况下实现力的控制。其次，每个手指都被约束在一个平行的运动机构中。该机构适合于机械加工，因为连接在手指上的刀具的方向保持恒定，并且机构本身可以在加工时抵抗大的反作用力。第三，手由两个三个自由度的手指组成，因此它可以适用于各种任务，包括装配和加工。在控制方面，设计了主从坐标控制系统，采用新设计的PID扰动观测器对主手指进行位置控制，对从手指进行PD阻抗力控制。研制了一种由并联运动机构、激光位移传感器和新设计的电磁致动器组成的实验微操作手。利用这只手，成功完成了微拉伸、微钻孔、孔内丝等各种微任务，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.