Potential Energy Distribution of Redundant Cable-Driven Robot Applied to Compliant Grippers: Method and Computational Analysis.

Rodriguez-Barroso Rodriguez-Barroso,Yakrangi Yakrangi,Saltaren Saltaren,Portilla Portilla,Cely Cely

doi:10.3390/s19153403

Rodriguez-Barroso Rodriguez-Barroso, Yakrangi Yakrangi + Show 3 more

Open Access

https://doi.org/10.3390/s19153403

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Abstract

Cable-driven parallel robots with a redundant configuration have infinite solutions for their cable tension distribution to provide a specific wrench to the end-effector. Redundancy is commonly used to increase the workspace and stiffness or to achieve secondary objectives like energetic minimization or additional movements. This article presents a method based on energy distribution to handle the redundancy of cable-driven parallel robots. This method allows the deformation and tension of each link to be related to the total energy available in the parallel robot. The study of energy distribution expression allows deformation, tension, and position to be combined. It also defines the range of tension and deformation that cables can achieve without altering the wrench exerted on the end-effector. This range is used with a passive reconfigurable end-effector to control the position of two grippers attached to some cables which act as compliant actuators. The relationship between the actuators’ energy and their corresponding gripper positions is also provided. In this way, energy measurement from the actuators allows the grasping state to be sensed. The results are validated using multibody dynamic software.

Highlights

Cable-driven parallel robots (CDPR) [1,2,3] are a kind of parallel robot whose links that connect the end-effector with actuators are cables
It defines the range of tension and deformation that cables can achieve without altering the wrench exerted on the end-effector. This range is used with a passive reconfigurable end-effector to control the position of two grippers attached to some cables which act as compliant actuators
The scope of this article is to use energy analysis to simplify the resolution of this problem and apply it to the movement of two grippers attached to two cables

Summary

Introduction

Cable-driven parallel robots (CDPR) [1,2,3] are a kind of parallel robot whose links that connect the end-effector with actuators are cables. Because they bend under compression forces, they need to be under tension to impose their kinematic restriction. One of the main differences between a CDPR and a usual parallel robot [5] is the flexibility and elasticity of the cables [6] This characteristic is used to control reconfigurable end-effectors with compliant actuators, as seen in [7], where the actuation of a single cable exerts an influence on two different bodies.

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