Ubiquitous Field Transportation Robots with Robust Wheel-Leg Transformable Modules

TL;DR

This paper presents two innovative field transportation robots with transformable wheel-leg modules, capable of adapting to diverse terrains and enhancing load capacity through novel design and control strategies validated by simulations and experiments.

Contribution

Introduces new wheel-leg modules driven by self-locking electric push rods, enabling accurate, stable mode switching and improved load capacity, with optimized parameters derived from mathematical models.

Findings

Robots successfully operate in challenging terrains with stable mode switching.

Transformable modules significantly enhance load capacity and terrain adaptability.

Control strategies verified through extensive simulations and field tests.

Abstract

This paper introduces two field transportation robots. Both robots are equipped with transformable wheel-leg modules, which can smoothly switch between operation modes and can work in various challenging terrains. SWhegPro, with six S-shaped legs, enables transporting loads in challenging uneven outdoor terrains. SWhegPro3, featuring four three-impeller wheels, has surprising stair-climbing performance in indoor scenarios. Different from ordinary gear-driven transformable mechanisms, the modular wheels we designed driven by self-locking electric push rods can switch modes accurately and stably with high loads, significantly improving the load capacity of the robot in leg mode. This study analyzes the robot's wheel-leg module operation when the terrain parameters change. Through the derivation of mathematical models and calculations based on simplified kinematic models, a method for optimizing the robot parameters and wheel-leg structure parameters is finally proposed.The design and control strategy are then verified through simulations and field experiments in various complex terrains, and the working performance of the two field transportation robots is calculated and analyzed by recording sensor data and proposing evaluation methods.