Rolling in the Deep – Hybrid Locomotion for Wheeled-Legged Robots using Online Trajectory Optimization


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Date

2020-04

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Wheeled-legged robots have the potential for highly agile and versatile locomotion. The combination of legs and wheels might be a solution for any real-world application requiring rapid, and long-distance mobility skills on challenging terrain. In this paper, we present an online trajectory optimization framework for wheeled quadrupedal robots capable of executing hybrid walking-driving locomotion strategies. By breaking down the optimization problem into a wheel and base trajectory planning, locomotion planning for high dimensional wheeled-legged robots becomes more tractable, can be solved in real-time on-board in a model predictive control fashion, and becomes robust against unpredicted disturbances. The reference motions are tracked by a hierarchical whole-body controller that sends torque commands to the robot. Our approach is verified on a quadrupedal robot with non-steerable wheels attached to its legs. The robot performs hybrid locomotion with a great variety of gait sequences on rough terrain. Besides, we validated the robotic platform at the Defense Advanced Research Projects Agency (DARPA) Subterranean Challenge, where the robot rapidly mapped, navigated and explored dynamic underground environments.

Publication status

published

Editor

Book title

Volume

5 (2)

Pages / Article No.

3626 - 3633

Publisher

IEEE

Event

Edition / version

Methods

Software

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Date collected

Date created

Subject

Legged robots; wheeled robots; motion and path planning; optimization and optimal control

Organisational unit

09570 - Hutter, Marco / Hutter, Marco check_circle
02284 - NFS Digitale Fabrikation / NCCR Digital Fabrication

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