A novel relative degree-of-freedom criterion for a class of parallel manipulators with kinematic redundancy and its applications. (November 2017)

• Record Type: Journal Article
• Authors: Qu, Haibo; Guo, Sheng; Zhang, Ying
• Is Part Of: Proceedings of the Institution of Mechanical Engineers. Volume 231:Number 22(2017)
• Page Start: 4227
• Page End: 4240
• Publication Date: 2017-11
• Subjects: Parallel manipulator -- kinematic redundancy -- relative degree-of-freedom criterion -- synthesis -- spherical joint; Mechanical engineering -- Periodicals; 621.05
• DOI: 10.1177/0954406216664756
• Languages: English
• ISSNs: 0954-4062

Abstract

The mobility of a whole parallel manipulator and the relative degree-of-freedom are the key points in mechanism synthesis and analysis, which often can be used to verify the existence of mechanisms. In this paper, the difference between the mobility of a parallel manipulator and the relative degree-of-freedom is discussed. First, a novel relative degree-of-freedom criterion is proposed based on the principle of determining the moving platform by N point positions, which is suitable for a kind of parallel manipulator with spherical joints attached to the moving platform. Next, the relative degree-of-freedom criterion is used to calculate the independent motions of the moving platform compared with the modified Kutzbach–Grübler criterion. The proposed relative degree-of-freedom criterion is different from the modified Kutzbach–Grübler criterion in result value and physical meaning. Finally, the type synthesis of such parallel manipulator with open-loop limbs or closed-loop limbs is performed based on the proposed relative degree-of-freedom criterion.