Distributed end-effector formation control for mixed fully- and under-actuated manipulators with flexible joints

TL;DR

This paper develops distributed control strategies for mixed fully- and under-actuated planar manipulators with flexible joints to maintain desired end-effector formations, including analysis of reachable shapes and validation through simulations.

Contribution

It introduces novel distributed control laws for mixed manipulator types with flexible joints, enabling formation keeping despite underactuation and faults.

Findings

Control laws successfully maintain formations in simulations.

Analysis of reachable formation shapes provided.

Distributed control handles underactuation and flexibility.

Abstract

The presence of faulty or underactuated manipulators can disrupt the end-effector formation keeping of a team of manipulators. Based on two-link planar manipulators, we investigate this end-effector formation keeping problem for mixed fully- and under-actuated manipulators with flexible joints. In this case, the underactuated manipulators can comprise of active-passive (AP) manipulators, passive-active (PA) manipulators, or a combination thereof. We propose distributed control laws for the different types of manipulators to achieve and maintain the desired formation shape of the end-effectors. It is achieved by assigning virtual springs to the end-effectors for the fully-actuated ones and to the virtual end-effectors for the under-actuated ones. We study further the set of all desired and reachable shapes for the networked manipulators' end-effectors. Finally, we validate our analysis via numerical simulations.