Gaitor: Learning a Unified Representation Across Gaits for Real-World Quadruped Locomotion

TL;DR

Gaitor introduces a unified, interpretable 2D latent space for quadruped gaits, enabling continuous gait transitions and terrain adaptation in simulation and real-world robots.

Contribution

This work is the first to learn a disentangled, continuous gait representation that allows smooth gait blending and terrain-aware control for quadruped robots.

Findings

Latent space enables continuous gait transitions.

Gaitor operates effectively on real quadruped robots.

Disentangled features allow independent gait characteristic control.

Abstract

The current state-of-the-art in quadruped locomotion is able to produce a variety of complex motions. These methods either rely on switching between a discrete set of skills or learn a distribution across gaits using complex black-box models. Alternatively, we present Gaitor, which learns a disentangled and 2D representation across locomotion gaits. This learnt representation forms a planning space for closed-loop control delivering continuous gait transitions and perceptive terrain traversal. Gaitor's latent space is readily interpretable and we discover that during gait transitions, novel unseen gaits emerge. The latent space is disentangled with respect to footswing heights and lengths. This means that these gait characteristics can be varied independently in the 2D latent representation. Together with a simple terrain encoding and a learnt planner operating in the latent space, Gaitor can take motion commands including desired gait type and swing characteristics all while reacting to uneven terrain. We evaluate Gaitor in both simulation and the real world on the ANYmal C platform. To the best of our knowledge, this is the first work learning a unified and interpretable latent space for multiple gaits, resulting in continuous blending between different locomotion modes on a real quadruped robot. An overview of the methods and results in this paper is found at https://youtu.be/eVFQbRyilCA.