Eric Rollins

The Atacama Desert Trek: outcomes

In June and July 1997, Nomad, a planetary-relevant mobile robot, traversed more than 220 kilometers across the barren Atacama Desert in Chile, exploring a landscape analogous to the surfaces of the Moon and Mars. In this unprecedented demonstration, Nomad operated both autonomously and under the control of operators thousands of kilometers away, addressing issues of robot configuration, communication, position estimation, and navigation in rugged, natural terrain. The field experiment also served to test technologies for remote geological investigation, paving the way for new exploration strategies on Earth and beyond. Finally, by combining safeguarded teleoperation with panoramic visualization and a novel user interface, the Atacama Desert Trek provided the general public a compelling interactive experience an opportunity to remotely drive an exploratory robot. Nomads performance in the Atacama Desert Trek set new benchmark in high performance robotics operations relevant to terrestrial and planetary exploration. This paper presents an overview of the experiment, describes technologies key to Nomads success, and discusses outcomes and implications.

A photo-realistic 3-D mapping system for extreme nuclear environments: Chernobyl

We present a stereoscopic mapping system for use in post-nuclear accident operations by the Pioneer robot. First we discuss a radiation shielded sensor array designed to tolerate extended cumulative dose using 4/spl times/ shielding. Next, we outline procedures to ensure timely, accurate range estimation using trinocular stereo. Finally, we review the implementation of a system for the integration of range information into a 3-D, textured, metrically accurate surface mesh.

Antenna pointing for high bandwidth communications from mobile robots

This paper discusses the challenge of achieving high bandwidth, distant range wireless communication from mobile robots by way of antenna tracking. In the case of robots traversing rough terrain at moderate speeds, tracking demands high slew rates and large motion ranges due to vehicle motion disturbances. Attaining tracking accuracy, particular with the low mass and power inherent to mobile robots, requires an innovative approach. This paper presents the requirements analysis, mechanism design, sensor configuration and some experimental results for an antenna pointing mechanism that was developed for Nomad, a planetary-relevant mobile robot. The mechanism was demonstrated during the summer of 1997 in Nomads 200 km traverse in the Atacama Desert of Chile.

Field validation of Nomad's robotic locomotion

During June and July of 1997, a mobile robot named Nomad traversed 223km in the Atacama Desert of southern Chile via transcontinental teleoperation. This unprecedented accomplishment is primarily attributed to Nomads innovative locomotion design which features four-wheel/all-wheel drive locomotion, a reconfigurable chassis, electronically coordinated steering, pivot-arm suspension, and body motion averaging. Nomads locomotion was configured through systematic analysis and simulations of the robots predicted performance in a variety of terrain negotiation scenarios. Experimental work with a single wheel apparatus was sued to determine the effect of repeated traffic and tread pattern on power draw. Field test before and during the Atacama traverse demonstrated Nomads substantial terrainability and autonomous navigation capabilities, and validated theoretical performance projections made during its geometric configuration. Most recently, the augmentation of the internal monitoring system with a variety of sensors has enabled a much more comprehensive characterization of Nomads terrain performance. Because of Nomads unique steering design a comparison of skid and explicit steering was performed by monitoring wheel torque and power during steady state turns. This paper summarizes the process and metrics of Nomads mobility configuration, and reports on experimental data gathered during locomotion testing.

A prototype locomotion concept for a lunar robotic explorer

Carnegie Mellon University is pursuing research of robotic vehicles for lunar exploration. In our mission scenario two rovers will traverse one thousand kilometers on the Moon over a period of two years, starting in 1998. Throughout the mission the rovers will transmit to Earth rich video telemetry to be used by theme parks ventures and scientist worldwide. Critical to achieving the goals of the two-year mission is the rovers locomotion capability. The requirements of survivability in the harsh lunar environment, substantial terrainability and long term reliability drive the configuration of the locomotion system. These performance requirements have led to the consideration of a wheeled configuration as the preferred locomotion scheme for the intended lunar traverse. To achieve substantial climbing capability and mitigate body excursions we selected a six-wheeled configuration that utilizes pivot arm linkages for body suspension. In this paper we discuss the configuration of robotic locomotion for the moon, and describe analysis and experimental results obtained through testing of a physical prototype.