Development Research of an In-Parallel Actuated Robot for High-Speed Machining

为了研制一种高速加工并联驱动机器人，对六自由度空间并联驱动机构进行了机构综合、设计、样机制作、实验测试，并开发了一种运动学标定方法。在关节运动范围和减速齿轮刚度约束下，通过评估实际工作空间和静刚度，综合了一个六自由度空间曲柄式并联驱动机构。在综合结果的基础上，制作了一个原型工作台。从工作空间、位置重复性、静刚度和动刚度等方面对样机工作台的基本特性进行了实验研究，证实样机具有良好的高速加工工作台的基本特性。构造了由原型工作台和固定在机架上的高速主轴组成的高速机床，并进行了高速加工试验。当工作材料为钢（SS400）， 4刃立铣刀直径为4mm，立铣刀转速为36000转/分，进给速度为6m/min，切削深度为0.03mm时，加工后实现的工作材料表面粗糙度小于1.3微米。为了提高工作台的绝对精度，提出了一种利用双球杆测量系统进行运动标定的方法，并给出了标定中一组输出运动的确定评价指标。

In order to develop an in-parallel actuated robot for high-speed machining, mechanism synthesis, design, prototyping, experimental tests of a spatial in-parallel actuated mechanism with six degrees of freedom and development of a method of kinematic calibration have been carried out. A spatial crank-type in-parallel actuated mechanism with six degrees of freedom has been synthesized by evaluating both the practical working space and static stiffness within the constraints of both motion range of joints and stiffness of reduction gears. Based on the result of synthesis, a prototype worktable has been manufactured. The basic characteristics of the prototype worktable has been experimentally investigated from the point of view of working space, position repeatability, static stiffness and dynamic stiffness, and it has been confirmed that the prototype has good basic characteristics as a worktable for high-speed machining. A high-speed machine tool that is composed of the prototype worktable and a high-speed spindle fixed on the frame has been constructed, and high-speed machining tests have been carried out. The realized surface roughness of the work material after the machining was less than 1.3 micrometer when the work material is steel(SS400), the diameter of the end mill with 4 edges is 4mm, revolution speed of the end mill is 36,000rpm, feed rate is 6m/min and depth of cut is 0.03mm. In order to improve absolute accuracy of the worktable, a method of kinematic calibration by using double ball bar measuring system has also been developed and an evaluation index for determination of a set of output motions used in the calibration has been developed.