Synthesis and analysis of plane-space switching mechanisms based on a plane-symmetric eight-bar linkage

Abstract

This paper proposes a novel synthesis method of constructing plane-space switching mechanisms based on the symmetric plane of the regular prism. First, the structure equation and motion characteristic of plane-symmetric eight-bar linkage are presented. Then the plane-symmetric seven-bar linkage and rhombic Bricard linkage are obtained by locking the joint of eight-bar linkage. Four types of plane-space switching mechanisms are constructed based on the synthesis method and switching linkage units. These switching mechanisms can expand completely into planar configurations and fold completely into spatial configurations. Subsequently, the kinematics of the coupled branch chain is analyzed, through which the folded and contractive characteristics of the mechanism are revealed. Then the concept of distributed circle of joints is proposed, and the enveloping performance of the mechanism is approximately analyzed. This paper provides a new idea and synthesis method for designing new deployable mechanisms.