5自由度大工作空间/支链行程比混联机械手的概念设计与尺度综合

研究一类新型5自由度可重构混联机械手的创新设计和尺度综合问题,该机械手模块由-2自由度球面并联机构和一条通过滑移副与之串接的两转动-移动串联运动链组成.该混联机械手由于将定点转动与相对滑移运动解耦,因此具有工作空间/支链行程比大的特点,适合高速轻载作业,可作为即插即用模块用于搭建不同类型的加工制造装备.在建立2自由度球面并联机构的速度映射模型的基础上,分析该机构的奇异性和各向同性问题,并以速度雅可比矩阵最小奇异值的全域均值为操作性能指标,研究2自由度球面并联机构的尺度综合问题.通过单调性分析揭示出尺度参数对该指标的影响规律,进而将尺度综合问题简化为求解杆长等式约束问题.最后给出一组算例,使该尺度综合方法的有效性得到验证.

KINEMATIC DESIGN OF 5-DOF HYBRID ROBOT WITH LARGE WORKSPACE/LIMB-STROKE RATIO

The conceptual design and dimensional synthesis of a novel 5-DOF reconfigurable hybrid robot module are presented. The module is composed of a 2-DOF parallel spherical mecha-nism which is serially connected with a 3-DOF open loop ki-nematic chain by a prismatic joint. The merit of this design is that a relatively large workspace/limb-stroke ratio can be achieved due to the decomposition of the fixed point rotation and the relative translation. The proposed 5-DOF hybrid robot can be employed as a plug-and-play module to configure dif-ferent machines for the circumstances where high-speed yet light payload is required. The singularity and isotropy of the 2-DOF spherical parallel mechanism are analyzed based on the velocity mapping function. The dimensional synthesis of the 2-DOF spherical parallel mechanism is carried out with a goal to maximize the mean value of the minimum singular value of the Jacobian matrix in the workspace subject to a set of appro-priate mechanical constraints. The results of the optimal kine-matic design are given via examples.