Jeffrey J. Biesiadecki

Athlete: A cargo handling and manipulation robot for the moon

A robotic vehicle called ATHLETE—the All-Terrain Hex-Limbed, Extra-Terrestrial Explorer—is described, along with initial results of field tests of two prototype vehicles. This vehicle concept is capable of efficient rolling mobility on moderate terrain and walking mobility on extreme terrain. Each limb has a quick-disconnect tool adapter so that it can perform general-purpose handling, assembly, maintenance, and servicing tasks using any or all of the limbs.

Attitude and position estimation on the Mars exploration rovers

NASA/JPLs Mars exploration rovers acquire their attitude upon command and autonomously propagate their attitude and position. The rovers use accelerometers and images of the sun to acquire attitude, autonomously searching the sky for the sun with an articulated camera. To propagate the attitude and position the rovers use either accelerometer and gyro readings or gyro readings and wheel odometry, depending on the nature of the movement Earth-based operators have commanded. Where necessary, visual odometry is performed on images to fine tune the position updates, particularly in high slip environments. The capability also exists for visual odometry attitude updates. This paper describes the techniques used by the rovers to acquire and maintain attitude and position knowledge, the accuracy which is obtainable, and lessons learned after more than one year in operation.

Mars Exploration Rover surface operations: driving spirit at Gusev Crater

Spirit is one of two rovers that landed on Mars in January 2004 as part of NASAs Mars Exploration Rover mission. As of July 2005, Spirit has traveled over 4.5 kilometers across the Martian surface while investigating rocks and soils, digging trenches to examine subsurface materials, and climbing hills to reach outcrops of bedrock. Originally designed to last 90 sols (Martian days), Spirit has survived over 500 sols of operation and continues to explore. During the mission, we achieved increases in efficiency, accuracy, and traverse capability through increasingly complex command sequences, growing experience, and updates to the on-board and ground-based software. Safe and precise mobility on slopes and in the presence of obstacles has been a primary factor in development of new software and techniques.

Mars Exploration Rover surface operations: driving opportunity at Meridiani Planum

Since landing on the Meridiani Planum region of Mars in January 2004, the Mars exploration rover (MER) vehicle named Opportunity has been sending back pictures taken from several different craters that would provide evidence that the region did indeed have a watery past. This paper details the experience of driving Opportunity through this alien landscape during its first 400 days on Mars, from the point of view of the other rover planners, the people who tell the rover where to drive and how to use its robotic arm

Traverse Performance Characterization for the Mars Science Laboratory Rover

It is anticipated that the Mars Science Laboratory rover, named Curiosity, will traverse 10–20 km on the surface of Mars during its primary mission. In preparation for this traverse, Earth-based tests were performed using Mars weight vehicles. These vehicles were driven over Mars analog bedrock, cohesive soil, and cohesionless sand at various slopes. Vehicle slip was characterized on each of these terrains versus slope for direct upslope driving. Results show that slopes up to 22 degrees are traversable on smooth bedrock and that slopes up to 28 degrees are traversable on some cohesive soils. In cohesionless sand, results show a sharp transition between moderate slip on 10 degree slopes and vehicle embedding at 17 degrees. For cohesionless sand, data are also presented showing the relationship between vehicle slip and wheel sinkage. Side by side testing of the Mars Exploration Rover test vehicle and the Mars Science Laboratory test vehicle show how increased wheel diameter leads to better slope climbing ability in sand for vehicles with nearly identical ground pressure. Lastly, preliminary data from Curiositys initial driving on Mars are presented and compared to the Earth-based testing, showing good agreement for the driving done during the first 250 Martian days.

Mars exploration rover surface operations: driving opportunity at Meridiani Planum

Since landing on the Meridiani Planum region of Mars in January 2004, the Mars exploration rover (MER) vehicle named Opportunity has been sending back pictures taken from several different craters that would provide evidence that the region did indeed have a watery past. This paper details the experience of driving Opportunity through this alien landscape during its first 400 days on Mars, from the point of view of the other rover planners, the people who tell the rover where to drive and how to use its robotic arm

ATHLETE mobility performance with active terrain compliance

The All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) is a modular, heavy-lift vehicle being developed to support NASA operations on the lunar surface. This agile system consists of a symmetrical arrangement of six limbs, each with six articulated degrees of freedom and a powered wheel. The design enables transport of bulky payloads over a wide range of terrains and is envisioned as a tool to mobilize habitats, power generation equipment, and other supplies in for long-range lunar exploration and lunar outpost construction. The first-generation prototype transports payloads of up to 300 kg in terrestrial testing, with flight models projected to carry at least 15 metric tons in a lunar gravity environment. 1 2

Sliding GAIT Algorithm for the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE)

The design of a surface robotic system typically involves a trade between the traverse speed of a wheeled rover and the terrain-negotiating capabilities of a multi-legged walker. The ATHLETE mobility system, with both articulated limbs and wheels, is uniquely capable of both driving and walking and has the flexibility to employ additional hybrid mobility modes. This paper introduces the Sliding Gait, an intermediate mobility algorithm faster than walking with better terrain-handling capabilities than wheeled mobility.Copyright

YaM - a framework for rapid software development

YaM is a software development framework with tools for facilitating the rapid development of software in a concurrent software development environment. YaM provides solutions for thorny development challenges associated with software reuse, managing multiple software configurations, developing of software product-lines, and multiple platform development and build management. YaM uses release-early, release-often development cycles to allow developers to incrementally integrate their changes into the system on a continual basis. YaM facilitates the creation and merging of branches to support the isolated development of immature software to avoid impacting the stability of the development effort YaM uses modules and packages to organize and share software across multiple software products. It uses the concepts of link and work modules to reduce sandbox setup times even when the code-base is large. One side-benefit is the enforcement of a strong module-level encapsulation of a modules functionality and interface. This increases design transparency, system stability as well as software reuse. YaM is in use by several mid-size software development teams including several developing mission-critical software