A Failure Identification and Recovery Framework for a Planar Reconfigurable Cable Driven Parallel Robot

TL;DR

This paper presents a fault-tolerant control framework for planar cable-driven parallel robots that detects cable failures online and reconfigures the robot's attachment points in real-time to recover the lost workspace.

Contribution

It introduces an integrated failure detection and reconfiguration scheme using an IMM algorithm and redundancy resolution for automatic task recovery in CDPRs.

Findings

Effective failure detection using end-effector data

Successful real-time reconfiguration for workspace recovery

Enhanced robustness of cable-driven robots

Abstract

In cable driven parallel robots (CDPRs), a single cable malfunction usually induces complete failure of the entire robot. However, the lost static workspace (due to failure) can often be recovered through reconfiguration of the cable attachment points on the frame. This capability is introduced by adding kinematic redundancies to the robot in the form of moving linear sliders that are manipulated in a real-time redundancy resolution controller. The presented work combines this controller with an online failure detection framework to develop a complete fault tolerant control scheme for automatic task recovery. This solution provides robustness by combining pose estimation of the end-effector with the failure detection through the application of an Interactive Multiple Model (IMM) algorithm relying only on end-effector information. The failure and pose estimation scheme is then tied into the redundancy resolution approach to produce a seamless automatic task (trajectory) recovery approach for cable failures.