ReachBot: A Small Robot for Large Mobile Manipulation Tasks

TL;DR

ReachBot is a novel small robot design that combines extendable booms with mobile manipulation to enable versatile, large workspace operations in low gravity or challenging terrains, especially useful for space applications.

Contribution

The paper introduces ReachBot, a new robotic concept that integrates extendable booms with mobile manipulation, offering increased workspace and robustness for space exploration tasks.

Findings

ReachBot's design reduces mass and complexity compared to traditional robots.

A 2D analytical model and waypoint-tracking controller demonstrate robustness in microgravity simulations.

ReachBot effectively handles disturbances and modeling errors in simulated environments.

Abstract

Robots are widely deployed in space environments because of their versatility and robustness. However, adverse gravity conditions and challenging terrain geometry expose the limitations of traditional robot designs, which are often forced to sacrifice one of mobility or manipulation capabilities to attain the other. Prospective climbing operations in these environments reveals a need for small, compact robots capable of versatile mobility and manipulation. We propose a novel robotic concept called ReachBot that fills this need by combining two existing technologies: extendable booms and mobile manipulation. ReachBot leverages the reach and tensile strength of extendable booms to achieve an outsized reachable workspace and wrench capability. Through their lightweight, compactable structure, these booms also reduce mass and complexity compared to traditional rigid-link articulated-arm designs. Using these advantages, ReachBot excels in mobile manipulation missions in low gravity or that require climbing, particularly when anchor points are sparse. After introducing the ReachBot concept, we discuss modeling approaches and strategies for increasing stability and robustness. We then develop a 2D analytical model for ReachBot's dynamics inspired by grasp models for dexterous manipulators. Next, we introduce a waypoint-tracking controller for a planar ReachBot in microgravity. Our simulation results demonstrate the controller's robustness to disturbances and modeling error. Finally, we briefly discuss next steps that build on these initially promising results to realize the full potential of ReachBot.