Development of a Spherical In-parallel Actuated Mechanism with Three Degrees of Freedom with Large Working Space and High Motion Transmissibility. 1st Report, Evaluation of Motion Transmissibility and Analysis of Working Space.

Abstract

For a spherical in-parallel actuated mechanism with three degrees of freedom in which the output link is connected to the base link by three connecting-chains composed of an input link, a coupler link and three revolute pairs each and moments are transmitted only in a specific direction from each coupler link to the output link, transmission index (TI) is proposed based on the power transmitted from input links to the output link. Static force analyses with consideration of elasticity of links have been carried out in the case where forces and moments are exerted on the output link as external loads, and a new mechanism design method of a spherical in-parallel actuated mechanism using transmission index which can be calculated only from geometrical conditions of the mechanism is derived. A spherical in-parallel actuated mechanism with three degrees of freedom with large working space, in which motion transmissibility is excellent and interferences among links do not occur, is proposed.