A force analysis of a 3-RPS parallel mechanism by using screw theory

Abstract

SUMMARYThe force analysis of parallel manipulators is one of the important issues for mechanical design and control, but it is quite difficult often because of the excessive unknowns. A new approach using screw theory for a 3-RPS parallel mechanism is proposed in this paper. It is able to markedly reduce the number of unknowns and even make the number of simultaneous equations to solve not more than six each time, which may be called force decoupling. With this method, first the main-pair reactions need to be solved for, and then, the active forces and constraint reactions of all other kinematic pairs can be simultaneously obtained by analyzing the equilibrium of each body one by one. Finally, a numerical example and a discussion are given.

Kinematic effects of number of legs in 6-DOF UPS parallel mechanisms

“…5 In this section, the jacobian analysis of the proposed PMs are approached by using the theory of screws (see ref. [21,[28][29][30]). Zhao et al 31 have proposed an intuitive geometrical approach to obtain the reciprocal screws in PM.…”

Review on 2R1T 3-DOF parallel mechanisms

“…3-RPPS机构的刚度分析, 从而在整个机构的刚度分 析中考虑了约束反力产生的变形. Zhao等人 [80] 采用 螺旋理论对3-RPS并联机构进行力分析, 该方法特点 在于大幅减少未知数的数目, 在计算上具有优势. 落 海伟等人 [81] 提出了基于子结构综合和静态凝聚技术 的3-RPS并联机构的静刚度建模方法, 该方法综合考 虑了铰链和支链弹性对机构静刚度的贡献.…”

Exploiting Higher Kinematic Performance - Using a 4-Legged Redundant PM Rather than Gough-Stewart Platforms

“…In this section the jacobian analysis of the proposed PMs are approached by using the theory of screws. Zhao et al (2011) proposed a new approach using the screw theory for force analysis, and implemented it on a 3-DOF 3-RPS parallel mechanism. Gallardo-Alvarado et al (2010) presented a new 5-DOF redundant parallel manipulator with two moving platforms, where the active limbs are attached to the fixed platform.…”