并联机床后置处理算法与系统

以6自由度6-TPS型并联机床为模型,阐述了生成控制数据的一般流程,指出后置处理必须解决的两个关键问题——工件坐标系定位和动平台位姿获取。针对不同位形,提出利用综合误差系数和综合误差度来评价终端运动精度,并据此将工件坐标系定位归结为一类兼顾作业空间和运动精度的有约束非线性规划问题;提出了一种利用5自由度刀位文件获得6自由度动平台位姿的方法;研究了笛卡儿空间的插补算法,并比较了两种不同方法所产生的不同刀具插补轨迹。最后介绍了基于以上算法所开发的后置处理系统的结构。

POSTPROCESSING ALGORITHMS AND SYSTEM FOR PARALLEL KINEMATIC MACHINE TOOLS

Based on the structure of 6-TPS parallel kinematic machine tools (PKMT) with 6 degrees of freedom(DOFS), the procedure to generate control data is introduced. Locating workpiece coordinate system and getting position and orientation of the mobile platform are two necessary issues in the process of postprocessing. Two measures, comprehensive error coefficient and comprehensive error degree, are defined to evaluate the precision for various configurations of this type of machines, and the locating of workpiece coordinate system is treated as a nonlinear programming which aims at guaranteeing workspace and improving machining precision. A method to get 6 DOF poses of mobile platform from 5 DOF cutter location data is presented. Interpolating algorithm in Descartes coordinate system is investigated and the results about the cutter trajectories produced by two different interpolating methods are given. At last, a postprocessor based on these algorithms mentioned above is introduced and its data flowing is set forth.