Detecting Grasping Sites in a Martian Lava Tube: Multi-Stage Perception Trade Study for ReachBot

Abstract

This paper presents a trade study analysis to design and evaluate the perception system architecture for ReachBot. ReachBot is a novel robotic concept that uses grippers at the end of deployable booms for navigation of rough terrain such as walls of caves and lava tubes. Previous studies on ReachBot have discussed the overall robot design, placement and number of deployable booms, and gripper mechanism design; however, analysis of the perception and sensing system remains underdeveloped. Because ReachBot can extend and interact with terrain over long distances on the order of several meters, a robust perception and sensing strategy is crucial to identify grasping locations and enable fully autonomous operation. This trade study focuses on developing the perception trade space and realizing such perception capabilities for a physical prototype. This work includes analysis of: (1) multiple-range sensing strategies for ReachBot, (2) sensor technologies for subsurface climbing robotics, (3) criteria for sensor evaluation, (4) positions and modalities of sensors on ReachBot, and (5) map representations of grasping locations. From our analysis, we identify the overall perception strategy and hardware configuration for a fully-instrumented case study mission to a Martian lava tube, and identify specific sensors for a hardware prototype. The final result of our trade study is a system design conducive to benchtop testing and prototype hardware development.

Figures (3)

• Figure 1: A diagram illustrating different ReachBot configuration concepts for a martian lava tube mission. (A) shows a ReachBot configuration concept using extendable booms. An eight-boom configuration has been explored in previous work. At the end of each boom is a microspine gripper that can grasp onto rough surfaces. (B) is an image of a ReachBot microspine gripper previously tested on lava tube rocks. (C) shows a ReachBot configuration that combines cables with booms for placing the grippers.
• Figure 2: A flowchart depicting the trade study process in this work detailed in Section \ref{['sec:tradestudy']}, which begins with the dictation of Science Goals for the mission. Initial engineering trades (dark green) are derived from science parameters, with perception requirements (light green) further derived downstream.
• Figure 3: A flowchart of perception system for ReachBot: with the environment as input, the system acquires data, processes data, and outputs mapping and localization products for the planner. The majority of this trade study focused on defining hardware constraints and optimization objectives (hardware, sensors). We also discuss different representation possibilities for ReachBot downstream in order to provide a full picture of the perception system.