Paul Tompkins

First Experiments in the Robotic Investigation of Life in the Atacama Desert of Chile

The Atacama Desert of northern Chile may be the most lifeless place on Earth, yet where the desert meets the Pacific coastal range desiccation-tolerant micro-organisms are known to exist. The gradient of biodiversity and habitats in the Atacama’s subregions remain unexplored and are the focus of the Life in the Atacama project. To conduct this investigation, long traverses must be made across the desert with instruments for geologic and biologic measurements. In this paper we motivate the Life in the Atacama project from both astrobiologic and robotic perspectives. We focus on some of the research challenges we are facing to enable endurance navigation, resource cognizance, and long-term survivability. We conducted our first scientific investigation and technical experiments in Chile with the mobile robot Hyperion. We describe the experiments and the results of our analysis. These results give us insight into the design of an effective robotic astrobiologist and into the methods by which we will conduct scientific investigation in the next field season.

Mission-level path planning and re-planning for rover exploration

The Life in the Atacama (LITA) project seeks to develop technologies for robotic life detection and apply them to the investigation of the Atacama Desert. Its field investigation in 2005 will demonstrate highly autonomous robotic science and daily multi-kilometer traverses over several weeks. A key component is mission-level path planning, which combines large-scale route selection, path and activity timing, and predictive energy management. Its purpose is to yield high-level plans for locomotion, solar charging and hibernation. We describe this new level of robotic autonomy and illustrate its performance from the field experiments in 2003. c 2005 Elsevier B.V. All rights reserved.

Sun-Synchronous Robotic Exploration: Technical Description and Field Experimentation

Sun-synchronous robotic exploration is accomplished by reasoning about sunlight: where the Sun is in the sky, where and when shadows will fall, and how much power can be obtained through various courses of action. We conducted experiments in the Canadian high arctic using a solar-powered rover to prove the concept of Sun-synchronous exploration. Using knowledge of orbital mechanics, local terrain, and locomotion power, the rover Hyperion planned Sun-synchronous routes to visit designated sites while obtaining the necessary solar power for continuous operation. Hyperion executed its plan, beginning and ending each 24-h period with batteries fully charged, after traveling two circuits of more than 6 km in barren, Mars-like terrain. The objective of the Sun-Synchronous Navigation project (http://www.frc.ri.cmu.edu/sunsync) was to create hardware and software technologies needed to realize Sun-synchronous exploration and to validate these technologies in field experimentation. In the process, we learned important technical lessons regarding rover mechanism, motion control, planning algorithms, and system architecture. In this paper we describe the concept of Sun-synchronous exploration. We overview the design of the robot Hyperion and the software system that enables it to operate in synchrony with the Sun. We then discuss results and lessons from analysis of our field experiments. This paper describes rover and planetary exploration research at Carnegie Mellon during 2000-2002.

First experiment in sun-synchronous exploration

Sun-synchronous exploration is accomplished by reasoning about sunlight: where the Sun is in the sky, where and when shadows will fall, and how much power can be obtained through various courses of action. In July 2001 a solar-powered rover, named Hyperion, completed two sun-synchronous exploration experiments in the Canadian high arctic (75/spl deg/N). Using knowledge of orbital mechanics, local terrain, and expected power consumption, Hyperion planned a sun-synchronous route to visit designated sites while obtaining the necessary solar power for continuous 24-hour operation. Hyperion executed its plan and returned to its starting location with batteries fully charged after traveling more than 6 kilometers in barren, Mars-analog terrain. We describe the concept of sun-synchronous exploration. We overview the design of the robot Hyperion and the software system that enables it to operate sun-synchronously. We then discuss results from analysis of our first experiment in sun-synchronous exploration and conclude with observations.

Mission planning for the Sun-Synchronous Navigation Field Experiment

Describes TEMPEST, a planner that enables a solar-powered rover to reason about path selection and event placement in terms of available solar energy and anticipated power draw. Unlike previous path planners, TEMPEST solves the coupled path, path timing and resource management problem. It combines information about mission objectives, operational constraints, the planetary environment and rover performance, and employs the Incremental Search Engine, a search algorithm that produces optimal paths through high-dimensional spaces. In July 2001, TEMPEST supported the Sun-Synchronous Navigation Field Experiment on Devon Island in the Canadian Arctic. The planner successfully selected time-sequenced, closed-circuit paths that enabled a solar-powered planetary rover prototype to traverse a multi-kilometer path over 24 hours with battery energy reserve. The field trial results motivate future work in mission re-planning, multiple resource constraint analysis and improved speed and memory performance. Our objective is to fulfill a need for resource-cognizant autonomy that is critical for future long-distance planetary surface missions.

Global path planning for Mars rover exploration

TEMPEST is a planner for long-range planetary navigation that bridges the gap between path planning and classical planning and scheduling. In addition to planning routes, our approach yields the timing and placement of actions to conserve and restore expendable resources and that abide by operational constraints. TEMPEST calls upon the incremental search engine (ISE) to enable heuristic path planning and efficient re-planning under global constraints, over a four dimensional state space. We describe our approach, then demonstrate how the planner operates in a simulated Mars science traverse. Following a brief summary of TEMPEST results from a recent rover field experiment, we evaluate our research progress and describe our current and future work.