Stein Variational Ergodic Search

TL;DR

This paper introduces Stein Variational Ergodic Search, a novel method that uses variational inference and ergodic search to enable robots to efficiently explore and adapt in continuous environments by optimizing distributions of coverage trajectories.

Contribution

It formulates ergodic search as a probabilistic inference problem and applies Stein variational methods to approximate trajectory distributions for improved exploration.

Findings

Enables efficient optimization of multiple coverage strategies.

Facilitates online adaptation in exploration tasks.

Demonstrates effectiveness in simulated and physical experiments.

Abstract

Exploration requires that robots reason about numerous ways to cover a space in response to dynamically changing conditions. However, in continuous domains there are potentially infinitely many options for robots to explore which can prove computationally challenging. How then should a robot efficiently optimize and choose exploration strategies to adopt? In this work, we explore this question through the use of variational inference to efficiently solve for distributions of coverage trajectories. Our approach leverages ergodic search methods to optimize coverage trajectories in continuous time and space. In order to reason about distributions of trajectories, we formulate ergodic search as a probabilistic inference problem. We propose to leverage Stein variational methods to approximate a posterior distribution over ergodic trajectories through parallel computation. As a result, it becomes possible to efficiently optimize distributions of feasible coverage trajectories for which robots can adapt exploration. We demonstrate that the proposed Stein variational ergodic search approach facilitates efficient identification of multiple coverage strategies and show online adaptation in a model-predictive control formulation. Simulated and physical experiments demonstrate adaptability and diversity in exploration strategies online.