Wang Yuxin

(School of Mechanical Engineering, Tongji University, Shanghai 200092)

Wang Yiming

(Department of Mechanical Engineering, Beijing Institute of Graphic Communication, Beijing 102600)

Chen Yushu

(School of Mechanical Engineering, Tianjin University, Tianjin 300072)

Huang Zhen

(College of Mechanical Engineering, Yanshan University, Qinhuangdao 066004)

Abstract: In order to investigate the concrete moving behaviors at bifurcation points, based on the homotopy method and the static bifurcation condition, the algorithm, which is capable to detect all the configuration branches and bifurcation points, is constructed. With the aid of the concept of maximum uncontrollable domain, uncontrollable orientation components of manipulators at singular points are analyzed. The study shows that the uncontrollable orientation components have relations with both characteristics of the bifurcation curves of configurations and control precision of input parameters. It is found that increasing the control precision of input parameters will reduce uncontrollable regions of manipulators at singularities. By this way, the controllability of manipulators near by singular points is enhanced.

Key words: Parallel manipulator  Bifurcation  Singularity  Maximum uncontrollable domain 

CLC No: TP242

国家自然科学基金(50375111)和教育部985项目“优秀青年教师教学、科研奖励基金”(1999076)资助项目. Received 20040219, received in revised form 20050120