STEP: State Estimator for Legged Robots Using a Preintegrated foot Velocity Factor

TL;DR

This paper introduces STEP, a novel state estimator for legged robots that leverages a preintegrated foot velocity factor, eliminating the need for contact detection and utilizing stereo camera data to improve pose estimation in challenging terrains.

Contribution

The paper presents a new preintegrated foot velocity factor that does not rely on non-slip assumptions and enables end effector pose estimation without contact detection.

Findings

Validated in harsh-environment simulations

Effective on uneven terrains

Works in slippery conditions

Abstract

We propose a novel state estimator for legged robots, STEP, achieved through a novel preintegrated foot velocity factor. In the preintegrated foot velocity factor, the usual non-slip assumption is not adopted. Instead, the end effector velocity becomes observable by exploiting the body speed obtained from a stereo camera. In other words, the preintegrated end effector's pose can be estimated. Another advantage of our approach is that it eliminates the necessity for a contact detection step, unlike the typical approaches. The proposed method has also been validated in harsh-environment simulations and real-world experiments containing uneven or slippery terrains.