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At least 343 records · Page 19

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NASA NTRS1990

Lunar rover developments at JPL

Results of previous JPL developments are summarized and the current work related to lunar roving missions is discussed. Objectives of a long lunar transverse are reviewed and include lunar resource prospecting and base site surveys. Rover design criteria are presented, noting that payload instrumentation would include both television cameras for driving and cameras producing panoramic facsimile for high-fidelity scientific imaging and landmark navigation, as well as a multipurpose imaging system with multispectral, close-up, and microscopic capabilities. Instrumentation providing for chemical and mineral analysis, a gravimeter, and a magnetometer are also important. Rover performance requirements include a capability to support a 50 kg payload mass with a rover mass of 500 to 600 kg, powering and supporting the payload, managing the on-board resources available to each instrument, and handling all of the mission data. Desert tests of lunar roving navigation and field geology are discussed.

Burke, James D.↗

NASA NTRS1990

Autonomous navigation and control of a Mars rover

A Mars rover will need to be able to navigate autonomously kilometers at a time. This paper outlines the sensing, perception, planning, and execution monitoring systems that are currently being designed for the rover. The sensing is based around stereo vision. The interpretation of the images use a registration of the depth map with a global height map provided by an orbiting spacecraft. Safe, low energy paths are then planned through the map, and expectations of what the rover's articulation sensors should sense are generated. These expectations are then used to ensure that the planned path is correctly being executed.

Miller, D. P.↗

NASA NTRS1990

A comparison of energy conversion systems for meeting the power requirements of manned rover for Mars missions

Several types of conversion systems of interest for a nuclear Mars manned application are examined, including: free-piston Stirling engines (FPSE), He/Xe closed Brayton cycle (CBC), CO2 open Brayton, and SiGe/GaP thermoelectric systems. Optimization studies were conducted to determine the impact of the conversion system on the overall mass of the nuclear power system and the mobility power requirement of the rover vehicle. The results of an analysis of a manned Mars rover equipped with a nuclear reactor power system show that the free-piston Stirling engine and the He/Xe closed Brayton cycle are the best available options for minimizing the overall mass and electric power requirements of the rover vehicle. While the current development of Brayton technology is further advanced than that of FPSE, the FPSE could provide approximately 13.5 percent lower mass than the He/Xe closed Brayton system. Results show that a specific mass of 160 is achievable with FPSE, for which the mass of the radiation shield (2.8 tons) is about half that for He/Xe CBC (5 tons).

El-Genk, Mohamed S.↗

NASA NTRS1992

Position determination of a lander and rover at Mars with Earth-based differential tracking

The presence of two or more landed or orbiting spacecraft at a planet provides the opportunity to perform extremely accurate Earth-based navigation by simultaneously acquiring Doppler data and either Same-Beam Interferometry (SBI) or ranging data. Covariance analyses were performed to investigate the accuracy with which lander and rover positions on the surface of Mars can be determined. Simultaneous acquisition of Doppler and ranging data from a lander and rover over two or more days enables determination of all components of their relative position to under 20 m. Acquiring one hour of Doppler and SBI enables three dimensional lander-rover relative position determination to better than 5 m. Twelve hours of Doppler and either SBI or ranging from a lander and a low circular or half synchronous circular Mars orbiter makes possible lander absolute position determination to tens of meters.

Kahn, R. D.↗

NASA NTRS1993

Sources Sought for Innovative Scientific Instrumentation for Scientific Lunar Rovers

Lunar rovers should be designed as integrated scientific measurement systems that address scientific goals as their main objective. Scientific goals for lunar rovers are presented. Teleoperated robotic field geologists will allow the science team to make discoveries using a wide range of sensory data collected by electronic 'eyes' and sophisticated scientific instrumentation. rovers need to operate in geologically interesting terrain (rock outcrops) and to identify and closely examine interesting rock samples. Enough flight-ready instruments are available to fly on the first mission, but additional instrument development based on emerging technology is desirable. Various instruments that need to be developed for later missions are described.

Meyer, C.↗

NASA NTRS1993

Design issues for Mars planetary rovers

The paper presents some of the design issues and vehicle requirements that need to be addressed for the Mars planetary rovers. Some of the designs currently being investigated, including the JPL rover, the Martin Marietta vehicle, and the French Space Agency's VAP project, are examined. The rover must satisfy such mission requirements as surveying the terrain, preparing the landing sites, loading and unloading components for base operations, and aiding in the recovery of in situ materials.

Lee, Gordon K. F.↗

NASA NTRS1993

Mobility analysis, simulation, and scale model testing for the design of wheeled planetary rovers

The use of computer based techniques to model and simulate wheeled rovers on rough natural terrains is considered. Physical models of a prototype vehicle can be used to test the correlation of the simulations in scaled testing. The computer approaches include a quasi-static planar or two dimensional analysis and design tool based on the traction necessary for the vehicle to have imminent mobility. The computer program modeled a six by six wheel drive vehicle of original kinematic configuration, called the Rocker Bogie. The Rocker Bogie was optimized using the quasi-static software with respect to its articulation parameters prior to fabrication of a prototype. In another approach used, the dynamics of the Rocker Bogie vehicle in 3-D space was modeled on an engineering workstation using commercial software. The model included the complex and nonlinear interaction of the tire and terrain. The results of the investigation yielded numerical and graphical results of the rover traversing rough terrain on the earth, moon, and Mars. In addition, animations of the rover excursions were also generated. A prototype vehicle was then used in a series of testbed and field experiments. Correspondence was then established between the computer models and the physical model. The results indicated the utility of the quasi-static tool for configurational design, as well as the predictive ability of the 3-D simulation to model the dynamic behavior of the vehicle over short traverses.

Lindemann, Randel A.↗

NASA NTRS1993

Mars rover mechanisms designed for Rocky 4

A Mars rover prototype vehicle named Rocky 4 was designed and built at JPL during the fall of 1991 and spring 1992. This vehicle is the fourth in a series of rovers designed to test vehicle mobility and navigation software. Rocky 4 was the first attempt to design a vehicle with 'flight like' mass and functionality. It was consequently necessary to develop highly efficient mechanisms and structures to meet the vehicles very tight mass limit of 3 Kg for the entire mobility system (7 Kg for the full system). This paper will discuss the key mechanisms developed for the rover's innovative drive and suspension system. These are the wheel drive and strut assembly, the rocker-bogie suspension mechanism and the differential pivot. The end-to-end design, analysis, fabrication and testing of these components will also be discussed as will their performance during field testing. The lessons learned from Rocky 4 are already proving invaluable for the design of Rocky 6. Rocky 6 is currently being designed to fly on NASA's MESUR mission to Mars scheduled to launch in 1996.

Rivellini, Tommaso P.↗

NASA NTRS1999

Mobility Sub-System for the Exploration Technology Rover

A new six-wheeled robotic roving vehicle was developed for NASA's Exploration Technology (ET) program. The rover which is called the Field, Integrated, Design, and Operations (FIDO) rover is being used for advanced technology development. In addition, copies of FIDO's Mobility Sub-System (MSS) are being used for software development in several NASA projects, including the prototype for the flight Athena Rover of the Mars Sample Return (MSR) 2003 mission. The focus of this paper is the work done on the MSS, specifically the development and test of the wheel drive actuators, which are fundamental to vehicle mobility.

Lindemann, Randel↗

NASA NTRS1999

A Comparison of Two Path Planners for Planetary Rovers

The paper presents two path planners suitable for planetary rovers. The first is based on fuzzy description of the terrain, and genetic algorithm to find a traversable path in a rugged terrain. The second planner uses a global optimization method with a cost function that is the path distance divided by the velocity limit obtained from the consideration of the rover static and dynamic stability. A description of both methods is provided, and the results of paths produced are given which show the effectiveness of the path planners in finding near optimal paths. The features of the methods and their suitability and application for rover path planning are compared

Tarokh, M.↗

NASA NTRS1999

Advanced Design and Implementation of a Control Architecture for Long Range Autonomous Planetary Rovers

An advanced design and implementation of a Control Architecture for Long Range Autonomous Planetary Rovers is presented using a hierarchical top-down task decomposition, and the common structure of each design is presented based on feedback control theory. Graphical programming is presented as a common intuitive language for the design when a large design team is composed of managers, architecture designers, engineers, programmers, and maintenance personnel. The whole design of the control architecture consists in the classic control concepts of cyclic data processing and event-driven reaction to achieve all the reasoning and behaviors needed. For this purpose, a commercial graphical tool is presented that includes the mentioned control capabilities. Messages queues are used for inter-communication among control functions, allowing Artificial Intelligence (AI) reasoning techniques based on queue manipulation. Experimental results show a highly autonomous control system running in real time on top the JPL micro-rover Rocky 7 controlling simultaneously several robotic devices. This paper validates the sinergy between Artificial Intelligence and classic control concepts in having in advanced Control Architecture for Long Range Autonomous Planetary Rovers.

Martin-Alvarez, A.↗

NASA NTRS1999

1999 Marsokhod Field Experiment: A Simulation of a Mars Rover Science Mission

A field experiment to simulate a rover mission to Mars was performed in February 1999. This experiment, the latest in a series of rover field experiments, was designed to demonstrate and validate technologies and investigation strategies for high-science, high-technology performance, and cost-effective planetary rover operations.

Stoker, C.↗

NASA NTRS2000

Field Experiments with Planetary Surface Rovers: Lessons for Mars Mission Architecture

Over the last decade, a variety of field experiments have been performed that simulate operations of a rover on Mars. These, in combination with the Pathfinder experience, lead to a realistic assessment of rover mission capabilities and to recommendations for rover technology and mission architecture to improve the science return of Mars exploration. A table summarizes field experiments that represent a range of possible mission designs and operational strategies. The experiments varied by the type and quality of imaging systems and other instrumentation, the use of orbital and aerial imaging and spectroscopy, the communcation bandwidth and command strategy, and the distance traveled. All mission simulations were blind field tests operated by science teams whose interpretations were compared to field ground truth providing an assessment of the accuracy of remote science interpretations and a better understanding of where improvements are needed.

Stoker, Carol↗

NASA NTRS2000

FIDO Field Trials in Preparation for Mars Rover Exploration and Discovery and Sample Return Missions

The Mars 2003 Mission may include a rover to acquire remote sensing and in-situ measurements of surface materials, including rock surfaces that have been cleared of dust and coatings by use of an abrasion tool. Mars Sample Return Missions for 2005 and beyond may include rovers with remote sensing and in-situ measurement capabilities. Further, these mobility platforms may have systems to drill into rocks and collect cores, acquire soil samples, and place the rock and soil samples in ascent vehicles. The point of this abstract is to document that these operations have already been shown to be tractable based on continuing field trials of the FIDO Mars prototype rover.

Arvidson, R. E.↗

NASA NTRS2001

A Rover Deployed Ground Penetrating Radar on Mars

Radar is a fundamental tool capable of addressing a variety of geological problems on Mars via collection of data suitable for interpreting variations in surface morphology and reflectivity. Surface-deployed ground penetrating radar (GPR) can help further constrain the geology and structure of the near surface of Mars by directly measuring the range and character of in situ radar properties. In recognition of this potential, a miniaturized, easily modified GPR is being developed for possible deployment on a future Mars rover and will enable definition of radar stratigraphy at high spatial resolution to depths of 10-20 meters. Ongoing development of a Mars impulse GPR with industry partners at Geophysical Survey Systems, Inc., focuses on design and testing of a prototype transducer array (with both high frequency bistatic and low frequency monostatic components) in parallel with fabrication of a low power, mass, and volume control unit. The operational depth of 10-20 meters is geared towards definition of stratigraphy, subsurface blocks, and structure at the decimeter to meter scale that is critical for establishing the geologic setting of the rover. GPR data can also be used to infer the degree of any post-depositional pedogenic alteration or weathering that has subsequently taken place, thereby enabling assessment of pristine versus secondary morphology at the landing site. As is the case for most remote sensing instruments, a GPR may not detect water unambiguously. Nevertheless, any local, near-surface occurrence of liquid water will lead to large, easily detected dielectric contrasts. Moreover, definition of stratigraphy and setting will help in evaluating the history of aqueous activity and where any water might occur and be accessible. Most importantly perhaps, GPR can provide critical context for other rover and orbital instruments/data sets. Hence, GPR deployment along well positioned transects in the vicinity of a lander should enable 3-D mapping of stratigraphy and could serve to guide direct subsurface sampling. Additional information is contained in the original extended abstract.

Grant, J. A.↗

NASA NTRS2001

Exploring the Martian Highlands using a Rover-Deployed Ground Penetrating Radar

The Martian highlands record a long and often complex history of geologic activity that has shaped the planet over time. Results of geologic mapping and new data from the Mars Global Surveyor spacecraft reveal layered surfaces created by multiple processes that are often mantled by eolian deposits. Knowledge of the near-surface stratigraphy as it relates to evolution of surface morphology will provide critical context for interpreting rover/lander remote sensing data and for defining the geologic setting of a highland lander. Rover-deployed ground penetrating radar (GPR) can directly measure the range and character of in situ radar properties, thereby helping to constrain near-surface geology and structure. As is the case for most remote sensing instruments, a GPR may not detect water unambiguously on Mars. Nevertheless, any local, near-surface occurrence of liquid water will lead to large, easily detected dielectric contrasts. Moreover, definition of stratigraphy and setting will help in evaluating the history of aqueous activity and where any water might occur and be accessible. GPR data can also be used to infer the degree of any post-depositional pedogenic alteration or weathering, thereby enabling assessment of pristine versus secondary morphology. Most importantly perhaps, GPR can provide critical context for other rover and orbital instruments/data sets. Hence, rover-deployment of a GPR deployment should enable 3-D mapping of local stratigraphy and could guide subsurface sampling.

Grant, J. A.↗

NASA NTRS2001

Mars Rovers: Past, Present, and Future

This viewgraph presentation provides information on the exploration of Mars through the use of rover vehicles. Mars is considered an interesting planet because it is the most like Earth of all known planets, and it may have or have had water on or below its surface. There are many different engineering design challenges for roving vehicles intended for Mars. These include: communications time delay, narrow communications bandwidth, extreme temperatures, rough and rocky terrain, the lack of a global positioning system, and dust. The Sojourner Rover specifications are provided including wheel diameter and instruments. There are prototypes being tested at NASA's Ames Research Center of the next generation Mars rovers.

Bualat, Maria↗

NASA NTRS1998

Testing Planetary Rovers: Technologies, Perspectives, and Lessons Learned

Rovers are a vital component of NASA's strategy for manned and unmanned exploration of space. For the past five years, the Intelligent Mechanisms Group at the NASA Ames Research Center has conducted a vigorous program of field testing of rovers from both technology and science team productivity perspective. In this talk, I will give an overview of the the last two years of the test program, focusing on tests conducted in the Painted Desert of Arizona, the Atacama desert in Chile, and on IMG participation in the Mars Pathfinder mission. An overview of autonomy, manipulation, and user interface technologies developed in response to these missions will be presented, and lesson's learned in these missions and their impact on future flight missions will be presented. I will close with some perspectives on how the testing program has affected current rover systems.

Thomas, Hans↗