Geometric Constraint of an Evolved Deployable Ball Mechanism

Abstract

This paper presents a novel method based on the virtual sliders for constructing a deployable ball mechanism and reveals the geometric constraint of the 20-bar ball mechanism and the radially foldable linkage that were extracted from the Hoberman switch-pitch structure. This leads to the development of the chain structure equation to unravel the radial motion characteristics of the mechanism and to the construction of the 20-bar ball mechanism with simulation and rapid prototyping process. The paper further presents position analysis and Jacobian matrix of the mechanism and simulation and numerical analysis are used to illustrate the kinematic characteristics. The analysis corresponds to motion in both simulation and prototyped ball mechanism.

Keywords

• ball mechanism
• eight-bar linkage
• geometric constraint
• kinematics
• hoberman switch-pitch structure