奇异接近度的评价方法  

Measure to Evaluate Closeness to Singular Configurations

作　　者：李浩[1] 张玉茹[1] 王党校[1] 

机构地区：[1]北京航空航天大学虚拟现实与系统国家重点实验室,北京100191

出　　处：《机械工程学报》2010年第23期128-134,共7页Journal of Mechanical Engineering

基　　金：国家自然科学基金(50575011);国家高技术研究发展计划(863计划;2008AA04Z206)资助项目

摘　　要：奇异是机构的常见特性。在并联机构的奇异点附近,动平台的力/力矩输出能力会明显降低。因此,判定工作空间内一点距离奇异的远近程度是并联机构设计的一个重要问题。针对这一问题,定义两种测度指标,分别用来度量位置奇异和姿态奇异的接近度,并用该指标定义拟奇异空间,该空间由所有接近奇异的点组成。当机构工作在拟奇异空间之外的任务空间,即可保证驱动关节力矩不超出驱动电动机的物理极限。最后以平面3-RRR机构为例,给出两种指标的计算方法和拟奇异空间以及任务空间的求解方法。Singularity is the common characteristics of mechanisms.The force/torque output capability of the moving platform will be obviously reduced,nearby the singular points of a parallel mechanism.So how to evaluate the distance from a point in workspace to singularity becomes an important issue in parallel mechanism design.Aiming at the above problem,two indexes are presented to measure the closeness to position singularity and orientation singularity.A quasi-singularity space is defined by the indexes which includes all points close to singular points.The actuator forces/torques can be guaranteed not to exceed output capacity of motors while the end-effector is outside the quasi-singularity space.An example of a 3-RRR parallel mechanism is given to formulate the method to calculate the two indexes,the quasi-singularity space and the task space.

关 键 词：并联机构 奇异性分析 奇异接近度 拟奇异空间 3-RRR机构 

分 类 号：TP242[自动化与计算机技术—检测技术与自动化装置]