Mechanism Design with Singularity Avoidance of Crystal-Inspired Deployable Structures

Yao Chen,Jian Feng,Jiayi Yan

doi:10.3390/cryst9080421

Abstract

Although deployable structures have important applications in various fields, developing a new form of structural configuration faces some scientific challenges. Furthermore, kinematic singularity frequently exists in these structures, which has a negative impact on deployment performance and stiffness. To deal with these problems, this paper obtains inspiration from crystals on two-dimensional (2D) space, and aims at developing symmetric deployable structures assembled by identical link members and periodic units. Mobility and compatibility conditions of crystal-inspired deployable structures are given, and a detailed design for novel joints with bevels gears is proposed to avoid singularity of these symmetric structures. According to feasible solutions to the compatibility conditions, several types of deployable structures are developed and verified to be mobile with a single degree of freedom. The results show that the proposed joint with bevel gears has a satisfactory singularity avoidance capability, and the assembled structures exhibit a good deployment performance. Because a crystal-inspired deployable structure can be gradually deployed to cover a large area, it has a potential engineering application as a macroscopic or mesoscale structure.

Highlights

Deployable structures have certain modes of internal mechanism, and they are capable of transforming from compactly stowed states into deployed states [1,2,3]
Inspired from crystals on 2D space, this study aims at dealing with developing large-scale and symmetric deployable structures assembled by identical link members, and proposing an effective approach for avoiding kinematic bifurcation by replacing the revolute joints that introduce singularity with novel joints
This study demonstrated the design of novel revolute joints with bevel gears to realize singularity avoidance and better deployment performance for crystal-inspired deployable structures

Summary

Introduction

Deployable structures have certain modes of internal mechanism, and they are capable of transforming from compactly stowed states into deployed states [1,2,3]. The link member connected by revolute joints at its ends is always utilized as basic units for assembling a large scale deployable structure [8,9,10,11]. These mechanisms have lesser mobility and redundant constraints, which will result in a sudden change of structural configuration and kinematic singularity

Objectives

Methods

Results

Discussion

Conclusion