This paper presents a novel framework for the analysis of a 3-RRR spherical parallel manipulator with coaxial input axes (coaxial SPM) with the focus on its infinite rotational motion capabilities and its effects on the manipulator’s characteristics. The framework consists of three phases. At first, an approach for obtaining unique solutions of forward and inverse kinematics problems is introduced for setting up univocal relation between coaxial SPM’s input joint positions and orientation of its end-effector. At the second phase, a method for generating infinite rotational motions of an end-effector is formulated. The third phase outlines numerical computation procedures of the coaxial SPM’s workspaces in the joint and Cartesian spaces, excluding singularity configurations and mechanical collisions of SPM’s links during infinite rotational motion. A 3D design model and an experimental prototype of the coaxial SPM is presented and utilized for numerical analysis and experimental verification of the presented framework supplemented by an accompanying video demonstration.

本文提出了一种用于分析具有同轴输入轴 (同轴 SPM) 的 3-RRR 球形平行机械手的新框架，重点是其无限旋转运动能力及其对机械手特性的影响。该框架由三个阶段组成。首先，引入了一种获得正向和逆向运动学问题的唯一解的方法，以在同轴 SPM 的输入关节位置与其末端执行器的方向之间建立单义关系。在第二阶段，制定了一种生成末端执行器无限旋转运动的方法。第三阶段概述了关节和笛卡尔空间中同轴 SPM 工作空间的数值计算程序，不包括无限旋转运动期间 SPM 链接的奇异配置和机械碰撞。