关键词: 并联机构, 运动分岔特性, 运动限定机构, 运动学

Abstract: A novel parallel mechanism with bifurcated motion is introduced by integrating a discontinuously movable mechanism in the limb design. The mechanism has instantaneously six degrees of freedom at a singularity point. With the discontinuously movable mechanism moving to different motion branches, the parallel mechanism has the ability to evolve into four configurations with different motion characteristics, including 3T motion configuration, 3R motion configuration, 2T1R motion configuration and 2R1T motion configuration. By rigidizing the input joints, the rationality of input scheme for this mechanism is identified based on screw theory. Six motors nearly mounted to the base can sufficiently drive the parallel mechanism to switch between different motion configurations and perform different motions. The forward and inverse kinematics of the mechanism in different configurations are given. The translational motions are independent with each other and decoupled with the rotational motions. Kinematics simulation is performed for the parallel mechanism and the results show that theoretical analyses are correct. The workspace of the parallel mechanism in a general configuration is given.

Key words: Bifurcated motion, Discontinuously movable mechanism, Kinematics, Parallel mechanism