3-PRS并联机器人概念设计与运动特性研究

提出一类拓扑构型为3-PRS的少自由度并联机器人的概念设计方案。基于旋量理论,研究了所提3-PRS并联机器人的自由度。计算结果表明,所提3-PRS并联机器人为一类具有1移动2转动(1T2R)运动能力的3自由度并联装置。在自由度分析的基础上,进一步构建了3-PRS并联机器人的运动学模型。通过求解闭环矢量运动方程,给出了该类并联机器人的运动学逆解的解析表达。基于所求的运动逆解,构建了考虑机器人几何约束的可达工作空间搜索流程,并据此给出了3-PRS并联机器人的可达工作空间映射。最后,通过参数灵敏度分析,揭示了3-PRS并联机器人主要尺度参数对其可达工作空间的影响规律。研究结果表明,3-PRS并联机器人各尺度参数对其可达工作空间的影响程度不尽一致,在进行机器人尺度综合时,应重点关注动平台半径的影响。

Research of Conceptual Design and Kinematic Characteristic of a 3-PRS Parallel Kinematic Machine

A conceptual design of a parallel kinematic machine(PKM)whose topological arrangement is a 3-PRS parallel mechanism is proposed.Based on the screw theory,the degree of freedom(DOF)of the proposed PKM is analyzed.The results show that the 3-PRS PKM possesses one translational and two rotational capabilities(1T2R).After the DOF analysis,a kinematics model is established.By solving the closed-loop vector motion equation,the analytical expression for the inverse kinematics solution of the proposed 3-PRS PKM is given.Based on the inverse kinematics solution,by considering the geometrical constraints,the reachable workspace search process is constructed,and the reachable workspace mapping of 3-PRS PKM is given.Finally,a sensitivity analysis is carried out to reveal the influences of some major dimensional parameters on the reachable workspace of 3-PRS PKM.The research results manifest that these dimensional parameters have different influences on the reachable workspace of 3-PRS PKM.Among all these parameters,the radius of the moving platform should be paid more attentions during the dimension synthesis of PKM.