Trial Manufacture of a Six Degrees-of-Freedom Very Fast Parallel Robot

HEXA型并联机器人是首席研究员与蒙彼利埃二世大学合作开发的一种超快速并联机器人，第一台样机已经达到了22G的最大加速度。主要研究成果如下：1.设计并制造了一种新型HEXA型并联机器人。该设计采用了低摩擦的大功率直驱电机，以实现预期的性能。对结构进行了考虑奇异点的运动学分析、计算惯性矩阵以评价结构的动态特性等。控制主机是一台装有实时操作系统的个人计算机：风河系统公司的VxWorks。在VxWorks中开发了六自由度运动控制的基本实验和系统测试的控制程序。并进行了性能评价实验。首先，进行了最大加速能力评价实验。研制的机器人的最大加速度为40G，大约是最初原型达到的22G的两倍。因此，已经实现了目标加速。其次，进行了频率响应实验。结果表明，该机器人的响应带宽约为40 Hz。该带宽大约是例如通常使用的斯图尔特平台型并联机器人的带宽的十倍。具有这种响应带宽的六自由度机器人在世界上是找不到的。因此，研制的机器人具有很强的创新性。微重力模拟器的运动台等已被认为是所开发的机器人的一个应用。实践证明，该应用很好地发挥了机器人的高速性能，具有广阔的应用前景。

The HEXA-type parallel robot is a very fast parallel robot that has been developed by the head investigator in collaboration with Montpellier II University, The first prototype has already attained the maximum acceleration of 22 G.This study aims at development of a new one of ultra high-speed with capability of twice the acceleration. The results of this study are summarized as follows :1. A new HEXA-type parallel robot has been designed and manufactured. The design employs high-power direct-drive motors with low friction in order to implement the aimed capability. Kinematic analysis to consider singular points, calculation of inertia matrices to evaluate dynamic characteristics, etc. have been done for optimization of the structure.2. The main computer for control is a personal computer with a real-time operating system : Wind River Systems' VxWorks. Control programs in the VxWorks have been developed for basic experiments of six degrees-of-freedom motion control and for test of the system.3. Experiments for performance evaluation have been done. First, experiment to evaluate maximum acceleration ability was done. The developed robot showed the maximum acceleration of 40 G.This is about twice as large as 22 G that the initial prototype attained. Thus the targeted acceleration has been achieved. Next, frequency response experiment was done. The results show that the response bandwidth of the robot is about 40 Hz. This bandwidth is about ten times as large as the one of, for example, a Stewart platform-type parallel robot which is commonly used. A six degrees-of-freedom robot with this response bandwidth cannot be found in the world. The developed robot is, therefore, very innovative.4. A motion table for a micro-gravity simulator, etc. has been considered as an application of the developed robot. It has been shown that the application exploits the high-speed ability of the robot very well and is promising.