Motion Planning for the On-orbit Grasping of a Non-cooperative Target Satellite with Collision Avoidance

A method for grasping a tumbling noncooperative target is presented, which is based on nonlinear optimization and collision avoidance. Motion constraints on the robot joints as well as on the end-effector forces are considered. Cost functions of interest address the robustness of the planned solutions during the tracking phase as well as actuation energy. The method is applied in simulation to different operational scenarios

Remote systems development

Potential space missions of the nineties and the next century require that we look at the broad category of remote systems as an important means to achieve cost-effective operations, exploration and colonization objectives. This paper addresses such missions, which can use remote systems technology as the basis for identifying required capabilities which must be provided. The relationship of the space-based tasks to similar tasks required for terrestrial applications is discussed. The development status of the required technology is assessed and major issues which must be addressed to meet future requirements are identified. This includes the proper mix of humans and machines, from pure teleoperation to full autonomy; the degree of worksite compatibility for a robotic system; and the required design parameters, such as degrees-of-freedom. Methods for resolution are discussed including analysis, graphical simulation and the use of laboratory test beds. Grumman experience in the application of these techniques to a variety of design issues are presented utilizing the Telerobotics Development Laboratory which includes a 17-DOF robot system, a variety of sensing elements, Deneb/IRIS graphics workstations and control stations. The use of task/worksite mockups, remote system development test beds and graphical analysis are discussed with examples of typical results such as estimates of task times, task feasibility and resulting recommendations for design changes. The relationship of this experience and lessons-learned to future development of remote systems is also discussed

The astronaut and the banana peel: An EVA retriever scenario

To prepare for the problem of accidents in Space Station activities, the Extravehicular Activity Retriever (EVAR) robot is being constructed, whose purpose is to retrieve astronauts and tools that float free of the Space Station. Advanced Decision Systems is at the beginning of a project to develop research software capable of guiding EVAR through the retrieval process. This involves addressing problems in machine vision, dexterous manipulation, real time construction of programs via speech input, and reactive execution of plans despite the mishaps and unexpected conditions that arise in uncontrolled domains. The problem analysis phase of this work is presented. An EVAR scenario is used to elucidate major domain and technical problems. An overview of the technical approach to prototyping an EVAR system is also presented

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 344)

This bibliography lists 125 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during January, 1989. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

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

Concept definition study for recovery of tumbling satellites. Volume 1: Executive summary, study results

The first assessment is made of the design requirements and conceptual definition of a front end kit to be transported on the currently defined Orbital Maneuvering Vehicle (OMV) and the Space Transportation System Shuttle Orbiter, to conduct remote, teleoperated recovery of disabled and noncontrollable, tumbling satellites. Previous studies did not quantify the dynamic characteristics of a tumbling satellite, nor did they appear to address the full spectrum of Tumbling Satellite Recovery systems requirements. Both of these aspects are investigated with useful results

Modeling and Control of a Flexible Space Robot to Capture a Tumbling Debris

RÉSUMÉ La conquête spatiale des 60 dernières années a généré une grande quantité d’objets à la dérive sur les orbites terrestres. Leur nombre grandissant constitue un danger omniprésent pour l’exploitation des satellites, et requiert aujourd’hui une intervention humaine pour réduire les risques de collision. En effet, l’estimation de leur croissance sur un horizon de 200 ans, connue sous le nom de “syndrôme de Kessler”, montre que l’accès à l’Espace sera grandement menacé si aucune mesure n’est prise pour endiguer cette prolifération. Le scientifique J.-C. Liou de la National Aeronautics and Space Administration (NASA) a montré que la tendance actuelle pourrait être stabilisée, voire inversée, si au moins cinq débris massifs étaient désorbités par an, tels que des satellites en fin de vie ou des étages supérieurs de lanceur. Parmi les nombreux concepts proposés pour cette mission, la robotique s’est imposée comme une des solutions les plus prometteuses grâce aux retours d’expérience des 30 dernières années. La Station Spatiale Internationale (ISS) possède déjà plusieurs bras robotiques opérationnels, et de nombreuses missions ont démontré le potentiel d’un tel système embarqué sur un satellite. Pour deux d’entre elles, des étapes fondamentales ont été validées pour le service en orbite,et s’avèrent être similaires aux problématiques de la désorbitation des débris. Cette thèse se concentre sur l’étape de capture d’un débris en rotation par un bras robotique ayant des segments flexibles. Cette phase comprend la planification de trajectoire et le contrôle du robot spatial, afin de saisir le point cible du débris de la façon la plus délicate possible. La validation des technologies nécessaires à un tel projet est quasiment impossible sur Terre, et requiert des moyens démesurés pour effectuer des essais en orbite. Par conséquent, la modélisation et la simulation de systèmes multi-corps flexibles est traitée en détails, et constitue une forte contribution de la thèse. À l’aide de ces modèles, une validation mixte est proposée par des essais expérimentaux, en reproduisant la cinématique en orbite par des manipulateurs industriels contrôlés par une simulation en temps réel. En résumé, cette thèse est construite autour des trois domaines suivants : la modélisation des robots spatiaux, le design de lois de contrôle, et leur validation sur un cas test. Dans un premier temps, la modélisation de robots spatiaux en condition d’apesanteur est développée pour une forme “en étoile”.----------ABSTRACT After 60 years of intensive satellite launches, the number of drifting objects in Earth orbits is reaching a shifting point, where human intervention is becoming necessary to reduce the threat of collision. Indeed, a 200 year forecast, known as the “Kessler syndrome”, states that space access will be greatly compromised if nothing is done to address the proliferation of these debris. Scientist J.-C. Liou from the National Aeronautics and Space Administration (NASA) has shown that the current trend could be reversed if at least five massive objects, such as dead satellites or rocket upper stages, were de-orbited each year. Among the various technical concepts considered for debris removal, robotics has emerged, over the last 30 years, as one of the most promising solutions. The International Space Station (ISS) already possesses fully operational robotic arms, and other missions have explored the potential of a manipulator embedded onto a satellite. During two of the latter, key capabilities have been demonstrated for on-orbit servicing, and prove to be equally useful for the purpose of debris removal. This thesis focuses on the close range capture of a tumbling debris by a robotic arm with light-weight flexible segments. This phase includes the motion planning and the control of a space robot, in order to smoothly catch a target point on the debris. The validation of such technologies is almost impossible on Earth and leads to prohibitive costs when performed on orbit. Therefore, the modeling and simulation of flexible multi-body systems has been investigated thoroughly, and is likewise a strong contribution of the thesis. Based on these models, an experimental validation is proposed by reproducing the on-orbit kinematics on a test bench made up of two industrial manipulators and driven by a real-time dynamic simulation. In a nutshell, the thesis is built around three main parts: the modeling of a space robot, the design of control laws, and their validation on a test case. The first part is dedicated to the flexible modeling of a space robot in conditions of weightlessness. A “star-shaped” multi-body system is considered, meaning that the rigid base carries various flexible appendages and robotic arms, assumed to be open mechanical chains only. The classic Newton-Euler and Lagrangian algorithms are brought together to account for the flexibility and to compute the dynamics in a numerically efficient way. The modeling step starts with the rigid fixed-base manipulators in order to introduce the notations, then, détails the flexible ones, and ends with the moving-base system to represent the space robots

NASA Automated Rendezvous and Capture Review. A compilation of the abstracts

This document presents a compilation of abstracts of papers solicited for presentation at the NASA Automated Rendezvous and Capture Review held in Williamsburg, VA on November 19-21, 1991. Due to limitations on time and other considerations, not all abstracts could be presented during the review. The organizing committee determined however, that all abstracts merited availability to all participants and represented data and information reflecting state-of-the-art of this technology which should be captured in one document for future use and reference. The organizing committee appreciates the interest shown in the review and the response by the authors in submitting these abstracts