Workspace-Based Design of Equivalent Compression Spring Legs for a 3-DoF Translational Tensegrity Robot

Abstract

Prior work has led to the development of a three-degree-of-freedom translational tensegrity robot. Due to inherent and unavoidable collisions between the struts of the tensegrity system that is used as the basis of the robot’s development, these were replaced by equivalent compression spring legs (ECSLs). In this paper, multiple ECSL design concepts are proposed to generate the desired force-deflection behavior, with some based on the use of variable radius drums (VRDs). The optimization of the VRD profiles based on the desired force-deflection behavior is demonstrated. The ECSL designs are then compared based on the corresponding size of the robot’s workspace. The impact on its workspace of the robot’s orientation with respect to the gravitational field is analyzed as is the amount of preload introduced in the robot’s members by the ECSLs. Recommendations on preferred ECSL designs are made for different applications.