Path tracking control of self-reconfigurable robot hTetro with four differential drive units

TL;DR

This paper presents a robust path tracking controller for a self-reconfigurable robot with four differential drive units, capable of handling complex trajectories and orientation changes, validated through experiments on the hTetro platform.

Contribution

It introduces a novel path tracking control method specifically designed for a self-reconfigurable robot with multiple differential drives, addressing singularities and discontinuous trajectories.

Findings

Controller successfully tracks complex paths with orientation changes.

Experimental validation demonstrates robustness and effectiveness.

Addresses mechanical and control singularities in reconfigurable robots.

Abstract

The research interest in mobile robots with independent steering wheels has been increasing over recent years due to their high mobility and better payload capacity over the systems using omnidirectional wheels. However, with more controllable degrees of freedom, almost all of the platforms include redundancy which is modeled using the instantaneous center of rotation (ICR). This paper deals with a Tetris inspired floor cleaning robot hTetro which consists of four interconnected differential-drive units, i.e., each module has a differential drive unit, which can steer individually. Differing from most other steerable wheeled mobile robots, the wheel arrangement of this robot changes because of its self-reconfigurability. In this paper, we proposed a robust path tracking controller that can handle discontinuous trajectories and sudden orientation changes. Singularity problems are resolved on both the mechanical aspect and control aspect. The controller is tested experimentally with the self-reconfigurable robotic platform hero, and results are discussed.