Kinematic Synthesis of Two-DOF Rotational Parallel Mechanism With Compensation for Position Error

摘要

A rotational parallel mechanism isproposed that can perform rotational output motionaround two axes and fine translational motion tocompensate for position error of a target point, the centerof rotation of the output link. This mechanism iscomposed of three connecting chains: one is a constraintchain without actuation and two are actuation chains,each with two actuators. The structures of the constraintand actuation chains were synthesized so that themechanism can perform fine translational motion forposition compensation while achieving a rotationaloutput motion within a large workspace. Dimensionalsynthesis was carried out taking into account singularitywith respect to actuation torque and output velocity, androtational output motion coupled with translationalcompensation motion for position error. Based on thesynthesis results, a prototype mechanism was designedand built. Experimental results regarding compensationfor position error of the target point are shown to supportour structural and dimensional syntheses.