A Symmetric Three Degree of Freedom Tensegrity Mechanism with Dual Operation Modes for Robot Actuation.

Tianyuan Wang,Mark A Post

doi:10.3390/biomimetics6020030

Abstract

Tensegrity robots that use bio-inspired structures have many superior properties over conventional robots with regard to strength, weight, compliance and robustness, which are indispensable to planetary exploration and harsh environment applications. Existing research has presented various tensegrity robots with abundant capabilities in broad scenarios but mostly not focused on articulation and manipulability. In this paper, we propose a novel tensegrity mechanism for robot actuation which greatly improves the agility and efficiency compared with existing ones. The design integrates two separate tensegrity substructures inspired by shoulder and hip joints of the human body and features a similar form to a hexapod platform. It mitigates detrimental antagonistic forces in the structural network for optimising actuation controllability and efficiency. We validated the design both on a prototype and in a Chrono Engine simulation that represents the first physically accurate simulation of a wheeled tensegrity robot. It can reach up to approximately , and in pitch, yaw and roll motion, respectively. The mechanism demonstrates good agility and controllability as an actuated robot linkage while preserving desirable properties of tensegrity structures. The design would potentially inspire more possibilities of agile tensegrity implementations that enable future robots with enhanced compliance, robustness and efficiency without a tradeoff.

Highlights

Research interests for planetary exploration and harsh environment operation have been a long-term focus in robots
The mechanism inherits biological tensegrity characteristics of light weight and compliance, while brings in improved agility, motion efficiency and compatibility adopting our design factors compared with existing tensegrity mechanisms
Unlike traditional Class-1 based tensegrity robots, our mechanism can be integrated with conventional robot systems to exploit advantages of both systems owing to its clean segmentation between the structural and mechanical parts and the impact on payload capacity due to introducing tensegrity is mitigated

Summary

Introduction

Research interests for planetary exploration and harsh environment operation have been a long-term focus in robots. The presence of environmental physical hazards and the need for rocket-based transport, it is challenging to sustain robot durability and reliability. These lead to robots for these applications having high demands in robustness, survivability, traversing ability and light weight, similar to demands on many kinds of biological systems. The wide use of leverage linkages and orthogonal attached components result in a large mass, as a tradeoff for building stiffness and strength [1]. Single point mechanical failures, which occur due to abrasion or external impact, normally lead to total failure of the linkage and severely affect the performance of the whole robot

Methods

Results

Conclusion