Design and Central Pattern Generator Control of a New Transformable Wheel-Legged Robot

TL;DR

This paper presents a novel transformable wheel-legged robot controlled by central pattern generators, demonstrating effective navigation over various terrains through a new design and CPG-based control strategies.

Contribution

It introduces a new wheel-legged robot with a transformable design and develops CPG-based controllers, including analysis and comparison of oscillator models for versatile terrain navigation.

Findings

CPG control effectively manages the robot's locomotion.

The robot successfully navigates level ground and obstacles.

Different oscillator models show varied performance in control tasks.

Abstract

This paper introduces a new wheel-legged robot and develops motion controllers based on central pattern generators (CPGs) for the robot to navigate over a range of terrains. A transformable leg-wheel design is considered and characterized in terms of key locomotion characteristics as a function of the design. Kinematic analysis is conducted based on a generalized four-bar mechanism driven by a coaxial hub arrangement. The analysis is used to inform the design of a central pattern generator to control the robot by mapping oscillator states to wheel-leg trajectories and implementing differential steering within the oscillator network. Three oscillator models are used as the basis of the CPGs, and their performance is compared over a range of inputs. The CPG-based controller is used to drive the developed robot prototype on level ground and over obstacles. Additional simulated tests are performed for uneven terrain negotiation and obstacle climbing. Results demonstrate the effectiveness of CPG control in transformable wheel-legged robots.