Distributed formation control for manipulator end-effectors

TL;DR

This paper introduces three distributed formation control methods for manipulator end-effectors, enabling shape maintenance in 2D/3D despite varying knowledge of system parameters, validated through simulations.

Contribution

It proposes novel distributed controllers for manipulators with perfect, uncertain, or unknown parameters, incorporating physical spring models and adaptive estimators.

Findings

Effective formation control demonstrated in simulations

Controllers handle parameter uncertainties

Works for planar and humanoid manipulators

Abstract

We present three classes of distributed formation controllers for achieving and maintaining the 2D/3D formation shape of manipulator end-effectors to cope with different scenarios due to availability of modeling parameters. We firstly present a distributed formation controller for manipulators whose system parameters are perfectly known. The formation control objective is achieved by assigning virtual springs between end-effectors and by adding damping terms at joints, which provides a clear physical interpretation of the proposed solution. Subsequently, we extend it to the case where manipulator kinematic and system parameters are not exactly known. An extra integrator and an adaptive estimator are introduced for gravitational compensation and stabilization, respectively. Simulation results with planar manipulators and with seven degree-of-freedom humanoid manipulator arms are presented to illustrate the effectiveness of the proposed approach.