2.2.2 Lunar Rovers

This segment of the program supports the development of robotics to satisfy the planned requirements for exploration of the surfaces of the Moon. These plans call for robotic reconnaissance and surveying systems preceding the eventual human missions to these bodies. During such missions robots will explore potential landing sites and areas of scientific interest, place science instruments, gather samples for analysis and possible return to Earth, gather and transmit video imagry, and provide images required to generate "virtual environments" of the Lunar surface. The robotic systems required for these operations will require high levels of local autonomy, including the ability to perform local navigation, regulate on-board resources, and schedule activities, all with limited ground command intervention. The objectives of the tasks within this segment of the program are to develop these abilities, as well as conduct research into mobility systems, miniature mechanisms, planning, and on-board navigation. Specific applications are to programs planned by the Space Science and Exploration user communities, as well as other commercial lunar resource utilization opportunities.

Autonomous Rover Technologies

Augmented Reality for Supervisory Control of Rovers

Lunar Telescope Assembly

Lunar Rover Demonstration

Technology Transfer Roadmap Details

Autonomous Rover Technology

The purpose of the Autonomous Rover Technologies task is to develop innovative perception, rover configuration, planning, and task-level control technologies that enable mobile robots to operate under control modes ranging from safeguarded teloperation to full autonomy. The aim is to enable rovers to operate reliably, over long durations in rugged, natural, unstructured environments. Technology development will feed into and respond to the Lunar Rover Demonstration focused research program.

Approach:

The technology development will focus on the key areas of perception, rover configuration, planning, and integrated systems.

1) Perception. Technologies that will be developed include (a) mapping local surface geometry using stereo vision and weak calibration methods, (b) estimating rover position, using multiple sensor fusion, visual landmarks, and celestial navigation, and (c) mapping large-scale surface geometry, using topographic analysis.

2) Rover Configuration. New locomotion concepts will be explored, including novel mechanisms for serpentine locomotion. Innovative designs for foreceful work mechansisms will be developed for tasks such as lunar regolith excavation, lunar outpost construction, and lunar telescope deployment.

3) Planning. The focus will be on planning for obstacle avoidance using stereo, in rough, previously unknown terrain. Extension to current planning techniques will enable the robot to better handle partially known terrain. Techniques to be investigated include planning under uncertainty and risk.

4) Integrated Systems. The perception, planning, and task-level control technologies will be tested in an integrated, real-world navigation system. Initially, the locomotion platform will be the Ratler, and when available it will be a lunar-worthy rover. As the Lunar Rover Demonstration task develops components, such as computing platforms and telemetry systems, they will be integrated and tested with the navigation system.

Focus and Directions:

FY 1994: Develop and demonstrate technologies including stereo mapping with no artificial calibration targets; Daedalus framewalker fabricated and assembled; formal model of TCA using Z notation and temporal logic.

FY 1995: Develop and demonstrate technologies for off-board safeguarded teloperation control from a remote operator station. Demonstrate technologies in 10 km test with existing rover in natural terrain. Primary mode of fault recovery will be operator intervention (such as via direct teleoperation control).

FY 1996: Develop technologies for on-board safeguarded teleoperation control. Demonstrate technologies in 10 km test with existing self-contained rover in diverse lunar terrain, including analogs to Apollo 11, Apollo 17, mare, and highland sites.

FY 1997: Develop technologies for entirely self-sufficient safeguarded teleoperation control. Demonstrate technologies in 10 km test with new lunar-relevant rover in diverse lunar terrain. Demonstrate visual position estimation using celestial navigation.

FY 1998: Develop technologies for long-duration, on-board autonomous control. Demonstrate technologies in 1 km test with self-contained rover in lunar mare-like terrain. Demonstrate rover-requested intervention, such as recharging batteries or resetting comm link.

Possible future directions:
Develop technologies for mixed mode control blending safeguarded teleoperation and autonomous control. Develop technologies for highly fault-tolerant mixed mode control. Demonstrate technologies in 10 km test in lunar mare-like terrain with self-contained rover and a 1 kilometer mean distance between operator interventions. Demonstrate technologies in 10 km test in mixture of mare and highland terrains, with self-contained rover and a 1 day mean time between operator interventions.

Point of Contact:
Eric Krotkov
(412) 268-3058
epk@cs.cmu.edu

Augmented Reality for Supervisory Control of Rovers

The purpose of the Augmented Reality for Supervisory Rover Control task is to develop and demonstrate augmented reality technology that improves supervisory control of rovers in natural terrain. The approach augments operator displays by overlaying raw rover-acquired imagery with additional information such as topographic landmarks, heading and position estimates, and planned routes. We will overlay this information in such a manner that it appears to "stick" to the terrain, independent of the rover's motion. These overlaid displays will create an augmented reality that decreases the cognitive burden on operators.

Technical Objectives:

The technical objective of the Augmented Reality for Supervisory Rover Control task is to develop augmented reality technology that improves supervisory control of rovers in natural terrain. This augmented reality will decrease the cognitive burden on operators by improving situational awareness.

Approach:

We will create an augmented reality interface for supervisory control of rovers. The system will perform image understanding, and present results to the operator in a disciplined format.

The image understanding tasks include the following: identify features in the images such as mountains and contour lines; track those features so that overlays "stick" to images; match the features with mapped landmarks in order to estimate the rover pose.

Using the results of the image understanding, the system will overlay helpful symbolic information on two central displays, one showing terrain maps and the other showing rover-acquired images. The overlay information will include the following: indications of image landmarks and the corresponding map landmarks, such that the operator can identify matches without long visual searches; current rover location and heading, with indications of uncertainty; future goals and intermediate waypoints; indications of visual events such as the appearance of a geographically important peak, or arrival at a historic area such as the Apollo 11 site.

As an example of how the system will prevent operators from getting lost, suppose a tall mountain peak appears in the rover-acquired image. The system will detect the peak in the image, and recognize it as a landmark. It will then match the landmark with the appropriate structure in the topographic map, and signal the correspondence by overlaying the same color symbol on top of the landmark in the image and in the map. With a few such matches, the system will estimate the rover position, and display it on the map. These displays will prevent operators from getting lost, and generally improve their situational awareness.

Focus and Direction:

FY96 Position estimation from matches between (a) topographic features automatically extracted from rover-acquired images and (b) topographic features automatically extracted from digital elevation maps

FY97 Evaluation of new operator interface, including image overlays that appear to "stick" to terrain features, in remotely driving existing CMU rover

Planned Milestones:

FY96 Position estimation from matches between (a) topographic features automatically extracted from rover-acquired images and (b) topographic features automatically extracted from digital elevation maps

FY97 Evaluation of new operator interface, including image overlays that appear to "stick" to terrain features, in remotely driving existing CMU rover

Point of Contact:
Eric Krotkov
(412) 268-3058
epk@cs.cmu.edu

Lunar Telescope Assembly

The purpose of the Lunar Telescope Deployment task is to develop and demonstrate telerobotic technologies that enable an unmanned lunar observatory that is constructed and operated from Earth. The specific lunar observatory of interest is an optical interferometric telescope.

The Lunar Telescope Deployment task will demonstrate terrestrial deployment of rover-mounted optical telescopes within a 1 kilometer diameter circle. The rovers will point each telescope at the same star, and relay the gathered light to a simulated beam combiner on a central lander mock-up. The demonstration will not include interferometry instrumentation or flight-qualified components.

Technical Objectives:

The technical objective of the Lunar Telescope Deployment task is to demonstrate telerobotic deployment and operation of an interferometric telescope. For deployment, the objective is to demonstrate emplacement of rover-mounted optical telescopes within a 1 kilometer diameter circle in a lunar mare-like terrestrial setting. For operation, the rovers will repeatedly (i) point each telescope at the same star, and (ii) relay the gathered light to a simulated beam combiner on a central lander mock-up.

Aproach:

The technology development will focus on four key issues:

1. Surface mobility to deploy the telescope elements on the lunar surface. The approach will be to use existing rovers such as Ratler (used in the Autonomous Rover Technologies task) and the Lunar Rover under construction (used in the Lunar Rover Demonstration task). We will implement mechanical and electrical interfaces between the telescope and mirror instruments and the rover structure and electronics.

2. Precise pointing and alignment of optical elements. The approach will be to implement a hierarchical, adaptive, multi-rate controller that closes feedback loops at various resolutions (degrees, tenths of degrees, hundredths of degrees) at various rates (minutes, seconds, milliseconds).

3. Precise metrology to measure viewing baselines and orientations. The approach will be to employ differential GPS for measuring distances, and to modify existing laser-based devices used in field surveying for measuring angles.

4. Supervised autonomous operation. The approach will be to develop a system control architecture enabling a relatively small ground operations effort. Key issues include an operator interface capable of monitoring and commanding multiple ground vehicles, rover-rover communications, and lander-rover communications.

Focus and Direction:

FY1996 Demonstrate indoor imaging with breadboard system with 10 meter baseline consisting of (i) a gimbal-mounted amateur telescope coupled with a steerable mirror, and (ii) a CCD camera.

FY1997 Demonstrate stellar imaging with field-portable system with 100 meter baseline consisting of telescope/mirror on hand cart and CCD camera on tripod.

FY1998 Demonstrate stellar imaging with single-rover system with 1,000 meter baseline consisting of telescope/mirror on rover and CCD camera on lander mock-up.

FY1999 Demonstrate interferometric imaging with multi-rover system with circular viewing area, 100 meters in diameter, consisting of multiple telescope/mirror pairs on rovers and multiple cameras on lander mock-up.

FY2000 Demonstrate autonomous operation of interferometric imaging with multi-rover system with circular viewing area 1,000 meters in diameter (Level One Milestone).

Planned Milestones:

FY1996 Demonstrate indoor imaging with breadboard system with 10 meter baseline consisting of (i) a gimbal-mounted amateur telescope coupled with a steerable mirror, and (ii) a CCD camera.

FY1997 Demonstrate stellar imaging with field-portable system with 100 meter baseline consisting of telescope/mirror on hand cart and CCD camera on tripod.

FY1998 Demonstrate stellar imaging with single-rover system with 1,000 meter baseline consisting of telescope/mirror on rover and CCD camera on lander mock-up.

FY1999 Demonstrate interferometric imaging with multi-rover system with circular viewing area, 100 meters in diameter, consisting of multiple telescope/mirror pairs on rovers and multiple cameras on lander mock-up.

FY2000 Demonstrate autonomous operation of interferometric imaging with multi-rover system with circular viewing area 1,000 meters in diameter (Level One Milestone).

Point of Contact:
Eric Krotkov
(412) 268-3058
epk@cs.cmu.edu

Lunar Rover Demonstration

The purpose of the Lunar Rover Demonstration task is to develop and demonstrate a convincing, comprehensive mobile robot mission capability required for a Lunar Rover Flight Mission. The project will demonstrate rover technologies suitable for lunar missions, and provide those technologies to NASA and commercial interests for scientific and private enterprise on the Moon.

Technical Objectives:

The technical objective of the Lunar Rover Demonstration task is to demonstrate a comprehensive mobile robot mission capability for "hands-off" rover operation. The primary objective is long-duration operation, with a target of two months of testing. Assuming 60 days at 8 hours per day, and an average travel speed of 0.15 meters per second, the traverse will cover approximately 250 km. The rover will operate in lunar analog terrain, which implies a desert setting (including crater and boulder features in a barren, arid environment). The specific setting will be selected based on cost and availability.

Approach:

To achieve mobile robotic lunar mission capability, the task will focus its efforts on three fronts: development of a lunar-relevant prototype rover, component testing, and rover field testing in lunar analog terrain.

1) Lunar-Relevant Rover Development. The rover will consist of a number of lunar-relevant systems, including locomotion, panospheric imagery, computing, electronics, and software. The design will be based on the concepts in the Preliminary Design Review conducted by this task in FY95. Other systems, such as power, communications, and thermal control, will not be lunar-relevant.

2) Component Testing. To validate key elements of the design, the task will subject critical components to rigorous testing under terrestrial conditions. Components will include actuators, wheels, computing, internal safeguarding, software, and panospheric imaging. Lunar conditions will be simulated in environmental chambers subject to their cost and to their availability at centers such as Lewis.

3) Field Trials. The scenario calls for the rover to perform a two-month traverse (approximately 250 kilometers) in a desert. Throughout, researchers, scientists, and partner organizations (science centers, schools, and commercial sponsors) will share time teleoperating the rover.

The project will leverage the insights and practical tools developed under the Autonomous Rover Technologies task. Specifically, it will transfer results of the basic research in perception, rover configuration, and task-level control and apply them in system design, development, and demonstration.

Focus and Direction:

FY 94 Demonstrate natural terrain traverse with an existing but modified rover; form Lunar Rover Consortium; configure new rover.

FY 95 Conduct Preliminary Design Review (PDR) for rover and its role in a lunar mission. Scope of rover review to include locomotion, communication, imagery, computing and electronics, software, power, and thermal control systems. Additional scope to include ground stations, visualization, failure analysis, fault recovery, and transition modes (rover transition from "observer" to "explorer", ground station transition from site to site).

96 Build lunar-relevant prototype rover. Develop and integrate locomotion, teleoperable control, communications, and visualization systems.

97 Perform field tests of prototype rover in lunar analog terrain for extended distance and duration.

Planned Milestones:

Dec 1994 Conduct Configuration Design Review based on design document entitled "Lunaquest Mission Concept."

Mar 1995 Demonstrate functional simulation of rover operating on synthetic terrain.

Jun 1995 Produce design documents for locomotion, pointing, and visualization subsystems.

Sep 1995 Conduct Preliminary Design Review (PDR) for rover and its role in a lunar mission. Scope of rover review to include locomotion, communication, imagery, computing, electronics, software, power, and thermal control systems. Additional scope to include ground stations, visualization, failure analysis, fault recovery, and transition modes (rover transition from "observer" to "explorer", ground station transition from site to site).

Dec 1995 Emulate failure modes and reliability measures.

FY 1996: Reference mission defined. Definition will specify class of tasks to be performed by rover, accuracy and precision of navigation, traverse duration (and resulting distance), climate conditions, communications bandwidth, interface capabilities, terrain types, and degree of public interaction.

FY 1996: Lunar-relevant prototype rover built. Coordinated motion control of all axes demonstrated by joystick driving over indoor obstacle course including steps, slopes, cross-slopes, ditches, and combinations of these obstacle types. Control demonstrated by path tracking and command following. Panospheric visualization demonstrated by image acquisition, dewarping, and display.

FY 1997: Component testing with respect to reference mission completed for actuators, wheels, computing, internal safeguarding, software, and panospheric imaging. Testing program will quantify performance and reliability as a function of critical variables including number of revolutions, amount of loading, soil properties, vibration frequency, shock intensity, thermal environment, number of thermal cycles, and illumination environment.

FY 1997: Field trials performed with prototype rover in lunar analog terrain. Performance goals include a two-month (approximately 250 km) traverse following the profile of the reference mission defined in FY96. Terrain safeguarding system to be derived from that developed in Autonomous Rover Technologies task.

Point of Contact:
Red Whittaker
(412) 268-6559
red@ri.cmu.edu