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NASA NTRS1989

Robotic sampling system for an unmanned Mars mission

A major robotics opportunity for NASA will be the Mars Rover/Sample Return Mission which could be launched as early as the 1990s. The exploratory portion of this mission will include two autonomous subsystems: the rover vehicle and a sample handling system. The sample handling system is the key to the process of collecting Martian soils. This system could include a core drill, a general-purpose manipulator, tools, containers, a return canister, certification hardware and a labeling system. Integrated into a functional package, the sample handling system is analogous to a complex robotic workcell. Discussed here are the different components of the system, their interfaces, forseeable problem areas and many options based on the scientific goals of the mission. The various interfaces in the sample handling process (component to component and handling system to rover) will be a major engineering effort. Two critical evaluation criteria that will be imposed on the system are flexibility and reliability. It needs to be flexible enough to adapt to different scenarios and environments and acquire the most desirable specimens for return to Earth. Scientists may decide to change the distribution and ratio of core samples to rock samples in the canister. The long distance and duration of this planetary mission places a reliability burden on the hardware. The communication time delay between Earth and Mars minimizes operator interaction (teleoperation, supervisory modes) with the sample handler. An intelligent system will be required to plan the actions, make sample choices, interpret sensor inputs, and query unknown surroundings. A combination of autonomous functions and supervised movements will be integrated into the sample handling system.

Chun, Wendell↗

NASA NTRS1989

Redundant sensorized arm+hand system for space telerobotized manipulation

An integrated system, composed of an arm, a wrist, and a mechanical multifingered hand is treated. The hand is on development for possible application in telemanipulation, and is realized in separate parts. The redundancy of the degrees of freedom of the system, the sensors, the application of logical rules, and the supervision of teleoperators may be applied in order to have an optimum of reliability of the system in space telemanipulations.

Rovetta, Alberto↗

NASA NTRS1989

Graphic overlays in high-precision teleoperation: Current and future work at JPL

In space teleoperation additional problems arise, including signal transmission time delays. These can greatly reduce operator performance. Recent advances in graphics open new possibilities for addressing these and other problems. Currently a multi-camera system with normal 3-D TV and video graphics capabilities is being developed. Trained and untrained operators will be tested for high precision performance using two force reflecting hand controllers and a voice recognition system to control two robot arms and up to 5 movable stereo or non-stereo TV cameras. A number of new techniques of integrating TV and video graphics displays to improve operator training and performance in teleoperation and supervised automation are evaluated.

Diner, Daniel B.↗

NASA NTRS1989

An intelligent, free-flying robot

The ground based demonstration of the extensive extravehicular activity (EVA) Retriever, a voice-supervised, intelligent, free flying robot, is designed to evaluate the capability to retrieve objects (astronauts, equipment, and tools) which have accidentally separated from the Space Station. The major objective of the EVA Retriever Project is to design, develop, and evaluate an integrated robotic hardware and on-board software system which autonomously: (1) performs system activation and check-out; (2) searches for and acquires the target; (3) plans and executes a rendezvous while continuously tracking the target; (4) avoids stationary and moving obstacles; (5) reaches for and grapples the target; (6) returns to transfer the object; and (7) returns to base.

Reuter, G. J.↗

NASA NTRS1988

An intelligent, free-flying robot

The ground-based demonstration of EVA Retriever, a voice-supervised, intelligent, free-flying robot, is designed to evaluate the capability to retrieve objects (astronauts, equipment, and tools) which have accidentally separated from the Space Station. The major objective of the EVA Retriever Project is to design, develop, and evaluate an integrated robotic hardware and on-board software system which autonomously: (1) performs system activation and check-out, (2) searches for and acquires the target, (3) plans and executes a rendezvous while continuously tracking the target, (4) avoids stationary and moving obstacles, (5) reaches for and grapples the target, (6) returns to transfer the object, and (7) returns to base.

Reuter, G. J.↗

NASA NTRS1988

NASA telerobot testbed development and core technology demonstration

In 1985, NASA initiated a major program of technology development and demonstration for robotics applications to space servicing, assembly, repair, and remote exploration. A ground-based telerobot testbed at the Jet Propulsion Laboratory has been the focal point within this program. Designed to prove technology concepts for supervised automation of increasingly unstructured and complex tasks, the testbed has reached an initial stage of integration. Several significant testbed experiments have been performed, including visual tracking and grapple of a satellite, dual-arm spatial coordination and manipulator control, force-reflecting teleoperations, and simulated task planning for a satellite servicing scenario. The current NASA plans for continuing testbed development and demonstration are also described.

Schenker, Paul S.↗

NASA NTRS1989

Advances in space robotics

The problem of the remote control of space operations is addressed by identifying the key technical challenge: the management of contact forces and the principal performance parameters. Three principal classes of devices for remote operation are identified: anthropomorphic exoskeletons, computer aided teleoperators, and supervised telerobots. Their fields of application are described, and areas in which progress has reached the level of system or subsystem laboratory demonstrations are indicated. Key test results, indicating performance at a level useful for design tradeoffs, are reported.

Varsi, Giulio↗

NASA NTRS1990

NASA's first dexterous space robot

NASA is developing the Flight Telerobotic Servicer (FTS), a robotic device that can be teleoperated under constant command of a human operator or run by itself under human supervision. Plans call for the FTS to assist the astronauts in the assembly, maintenance, servicing, and inspection of Space Station Freedom. The FTS project is driven by five major objectives: to reduce Space Station dependence on crew EVA, improve crew safety, enhance crew utilization, promote remote servicing capabilities for platforms, and accelerate technology transfer from research to U.S. industry. Another part of the FTS project is a ground system that will support operations and system evolution. Not only will the FTS provide a needed operational capability during the assembly and operation of Space Station Freedom, it will also provide an expanding foundation for proving more advanced robotic and telepresence concepts in space.

Mccain, Harry G.↗

NASA NTRS1990

Neurobiological computational models in structural analysis and design

The present paper examines the role of neural computing strategies in structural analysis and design. A principal focus of the work resides in the use of neural networks to represent the force-displacement relationship in static structural analysis. Such models provide computationally efficient capabilities for reanalysis, and appear to be well suited for application in numerical optimum design. The paper presents an overview of the neural computing approach, with special emphasis on supervised learning techniques adopted in the present work. Special features of such learning strategies which have a direct bearing on numerical accuracy and efficiency, are examined in the context of representative structural optimization problems.

Hajela, P.↗

NASA NTRS1990

Energy absorption, lean body mass, and total body fat changes during 5 weeks of continuous bed rest

The nature of the body composition changes due to inactivity was examined together with the question of whether these changes are secondary to changes in energy absorption. Volunteers were 15 healthy males who lived on a metabolic research ward under close staff supervision for 11 weeks. Subjects were ambulatory during the first six weeks and remained in continuous bed rest for the last five weeks of the study. Six male volunteers (age 24-61 years) were selected for body composition measurements. Nine different male volunteers (age 21-50 years) were selected for energy absorption measurements. The volunteers were fed weighed conventional foods on a constant 7-d rotation menu. The average daily caloric content was 2,592 kcal. Comparing the five weeks of continuous bed rest with the previous six weeks of ambulation, it was observed that there was no change in energy absorption or total body weight during bed rest, but a significant decrease in lean body mass and a significant increase in total body fat (p less than 0.05).

Krebs, Jean M.↗

NASA NTRS1989

The Environment-Power System Analysis Tool development program

The Environment Power System Analysis Tool (EPSAT) is being developed to provide engineers with the ability to assess the effects of a broad range of environmental interactions on space power systems. A unique user-interface-data-dictionary code architecture oversees a collection of existing and future environmental modeling codes (e.g., neutral density) and physical interaction models (e.g., sheath ionization). The user-interface presents the engineer with tables, graphs, and plots which, under supervision of the data dictionary, are automatically updated in response to parameter change. EPSAT thus provides the engineer with a comprehensive and responsive environmental assessment tool and the scientist with a framework into which new environmental or physical models can be easily incorporated.

Jongeward, Gary A.↗

NASA NTRS1989

A perception system for a planetary explorer

To perform planetary exploration without human supervision, a complete autonomous robot must be able to model its environment and to locate itself while exploring its surroundings. For that purpose, the authors propose a modular perception system for an autonomous explorer. The perception system maintains a consistent internal representation of the observed terrain from multiple sensor views. The representation can be accessed from other modules through queries. The perception system is intended to be used by the Ambler, a six-legged vehicle being built at CMU. A partial implementation of the system using a range scanner is presented as well as experimental results on a testbed that includes the sensor, one computer-controlled leg, and obstacles on a sandy surface.

Hebert, M.↗

NASA NTRS1990

ACTS propagation program

The Advanced Communications Technology Satellite (ACTS) Propagation Program is organized to fulfill certain needs and requirements of the ACTS community. It is hoped that issues related to propagation effects in the context of ACTS experiments can be addressed and resolved by this program. The objectives of the ACTS Propagation Program are included in but not limited to planning for propagation measurements and studies using ACTS; organizing propagation experimenters who want to use ACTS into one group; developing observation stations for ACTS propagation measurements; supervising data collection, analysis, and ensure uniformity of data recording among various experimenters; and assisting the ACTS Program Office to carry out its objectives. This program is organized and managed by the NASA Propagation Program at the Jet Propulsion Laboratory. Financial support for this program is provided by NASA.

Davarian, Faramaz↗

NASA NTRS1990

Remote sensing of Earth terrain

Remote sensing of earth terrain is examined. The layered random medium model is used to investigate the fully polarimetric scattering of electromagnetic waves from vegetation. The model is used to interpret the measured data for vegetation fields such as rice, wheat, or soybean over water or soil. Accurate calibration of polarimetric radar systems is essential for the polarimetric remote sensing of earth terrain. A polarimetric calibration algorithm using three arbitrary in-scene reflectors is developed. In the interpretation of active and passive microwave remote sensing data from the earth terrain, the random medium model was shown to be quite successful. A multivariate K-distribution is proposed to model the statistics of fully polarimetric radar returns from earth terrain. In the terrain cover classification using the synthetic aperture radar (SAR) images, the applications of the K-distribution model will provide better performance than the conventional Gaussian classifiers. The layered random medium model is used to study the polarimetric response of sea ice. Supervised and unsupervised classification procedures are also developed and applied to synthetic aperture radar polarimetric images in order to identify their various earth terrain components for more than two classes. These classification procedures were applied to San Francisco Bay and Traverse City SAR images.

Kong, Jin AU↗

NASA NTRS1991

Near ground level sensing for spatial analysis of vegetation

Measured changes in vegetation indicate the dynamics of ecological processes and can identify the impacts from disturbances. Traditional methods of vegetation analysis tend to be slow because they are labor intensive; as a result, these methods are often confined to small local area measurements. Scientists need new algorithms and instruments that will allow them to efficiently study environmental dynamics across a range of different spatial scales. A new methodology that addresses this problem is presented. This methodology includes the acquisition, processing, and presentation of near ground level image data and its corresponding spatial characteristics. The systematic approach taken encompasses a feature extraction process, a supervised and unsupervised classification process, and a region labeling process yielding spatial information.

Sauer, Tom↗

NASA NTRS1990

Results from teleoperated free-flying spacecraft simulations in the Martin Marietta space operations simulator lab

To augment the capabilities of the Space Transportation System, NASA has funded studies and developed programs aimed at developing reusable, remotely piloted spacecraft and satellite servicing systems capable of delivering, retrieving, and servicing payloads at altitudes and inclinations beyond the reach of the present Shuttle Orbiters. Since the mid 1970's, researchers at the Martin Marietta Astronautics Group Space Operations Simulation (SOS) Laboratory have been engaged in investigations of remotely piloted and supervised autonomous spacecraft operations. These investigations were based on high fidelity, real-time simulations and have covered a wide range of human factors issues related to controllability. Among these are: (1) mission conditions, including thruster plume impingements and signal time delays; (2) vehicle performance variables, including control authority, control harmony, minimum impulse, and cross coupling of accelerations; (3) maneuvering task requirements such as target distance and dynamics; (4) control parameters including various control modes and rate/displacement deadbands; and (5) display parameters involving camera placement and function, visual aids, and presentation of operational feedback from the spacecraft. This presentation includes a brief description of the capabilities of the SOS Lab to simulate real-time free-flyer operations using live video, advanced technology ground and on-orbit workstations, and sophisticated computer models of on-orbit spacecraft behavior. Sample results from human factors studies in the five categories cited above are provided.

Hartley, Craig S.↗

NASA NTRS1990

Site characterization rover missions

Concepts for site characterization rovers capable of efficient operation on Mars with human supervision from earth are discussed. In particular, attention is given to strategies for developing and evaluating the necessary technology for implementing the roving vehicles and process technologies required for a systematic and integrated implementation of technologically advanced rovers. A vehicle testbed program is also described.

Pivirotto, Donna Shirley↗

NASA NTRS1990

Requirements for a near-earth space tug vehicle

The requirement for a small but powerful space tug, which will be capable of autonomous orbital rendezvous, docking and translating cargos between near-earth orbits by the end of this decade to support the growing national and international space infrastructure focused near the Space Station Freedom, is described. An aggregate of missions drives the need for a space tug including reboosting decaying satellites back to their operational altitudes, retrieving failed or exhausted satellites to Shuttle or SSF for on-orbit refueling or repair, and transporting a satellite servicer system with an FTS to ailing satellites for supervised in-place repair. It is shown that the development and operation of a space tug to perform such numerous missions is more cost effective than separate module and satellite systems to perform the same tasks.

Gunn, Charles R.↗