178 research outputs found

    Design guidelines for remotely maintainable equipment

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    The quantity and complexity of on-orbit assets will increase significantly over the next decade. Maintaining and servicing these costly assets represent a difficult challenge. Three general methods are proposed to maintain equipment while it is still in orbit: an extravehicular activity (EVA) crew can perform the task in an unpressurized maintenance area outside any space vehicle; an intravehicular activity (IVA) crew can perform the maintenance in a shirt sleeve environment, perhaps at a special maintenance work station in a space vehicle; or a telerobotic manipulator can perform the maintenance in an unpressurized maintenance area at a distance from the crew (who may be EVA, IVA, or on the ground). However, crew EVA may not always be possible; the crew may have other demands on their time that take precedence. In addition, the orbit of the tasks themselves may be impossible for crew entry. Also crew IVA may not always be possible as option for equipment maintenance. For example, the equipment may be too large to fit through the vehicle airlock. Therefore, in some circumstances, the third option, telerobotic manipulation, may be the only feasible option. Telerobotic manipulation has, therefore, an important role for on-orbit maintenance. It is not only used for the reasons outlined above, but also used in some cases as backup to the EVA crew in an orbit that they can reach

    Paper Session II-B - Sensor Data Display For Telerobotic Systems

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    Future earth orbiting, lunar and planetary missions will require the performance of tasks that are beyond human capability or are in an environment where human entry would be too costly or too hostile. These tasks will be candidates for performance by telerobotic systems whereby an electro-mechanical manipulator device performs the task in the remote hostile environment and the operator controlling or supervising the task remains at a work station in a safe location. Efficient operator participation in a telerobotic task occurs only when operators experience telepresence , that is they feel that they are present at the remote site in making the various decisions to control the task. Telepresence is therefore enhanced by presenting to operators the various inputs, for example visual, tactile, and force/torque information, that they would receive if they were actually present at the remote site. This paper addresses the problem of enhancing telepresence by displaying telerobotic sensor information to operators at their work stations. The paper is divided into four sections. First, a discussion is presented on some of the problems of displaying data from remote tasks. Second, an effort at Rockwell International to identify requirements for operator friendly display of data from telerobotic sensors, i£ described. Third, work performed at Rockwell s Robotic Facility is addressed. This work involves the integration of various sensors on a telerobotic device, and the design and implementation of operator friendly data display which adheres to the guidelines described above. Lastly, our future research plans and objectives in this area are discussed

    Detection and Molecular Characterization of Cryptosporidium species in Recreational Waters of Chaharmahal va Bakhtiyari Province of Iran using nested-PCR-RFLP

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    Background: The aim of this study was to detect and characterize Cryptosporidium spp. in water sam­ples collected from recreational ponds of Chaharmahal va Bakhtiyari Province of Iran .Meth­ods: Thirty water samples were collected from November 2009 to May 2010. Each sample con­tained 10 liters of water. We used the SSU rRNA-based PCR-RFLP technique.Results: Out of thirty samples examined, 6 (20%) were positive for different Cryptosporidium spp. Restriction pattern analysis showed that C. parvum has been the most prevalent genotype, fol­lowed by C. hominis and C. canis , respectively. In this area, the higher prevalence of C. par­vum compared with other genotypes is consistent with the distribution of cattle.Conclusion: Farm animals, particularly cattle are the main source of cryptosporidial contamina­tion for recreational waters in this area

    A Comparative 6-Month Clinical Study of Acellular Dermal Matrix Allograft and Subepithelial Connective Tissue Graft for Root Coverage

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    Objective: Different surgical procedures have been proposed for the treatment of gingival recessions. The goal of this study was to compare the clinical results of gingival recession treatment using Subepithelial Connective Tissue Graft and an Acellular Dermal MatrixAllograft.Materials and Methods: The present study was performed on 5 patients with 9 bilateral Miller`s class I or II gingival recessions. This included 15 premolars and 3 canines. In each patient the teeth were randomly divided in two groups of test (ADMA) and control (SCTG).Clinical parameters including recession height (RH), recession width (RW), keratinized gingiva (KG), clinical attachment level (CAL) and probing depth (PD) were measured at baseline, 2, 4 and 6 months after surgery and data analysis was performed using the Wilcoxon signed rank test.Results: The mean changes (mm) from baseline to 6 months in SCTG and ADMA were 2.22±0.83 and 1.77±0.66 decrease in RH, 2.55±0.88 and 2.33±0.86 decrease in RW,1.44±0.88 and 2.0±1.11 increase in KG, 2.33±1.22 and 2.11±0.6 decrease in CAL and finally 0.22±0.66 and 0.33±0.7 decrease in PD, respectively. The differences in meanchanges were not significant between the two groups in any of the parameters. The percentage of root coverage was 85.7% and 71.1% for the control and test group,respectively. The changes from baseline to the 6 month visit were significant for both groups in all parameters but PD.Conclusion: Alloderm may be suggested as an acceptable substitute for connective tissue graft considering the root coverage effect and KG width increase

    Paper Session I-B - Autonomous Robotic Systems For SEI Tasks

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    On the 20th anniversary, in 1989, of our country\u27s triumphant first landing on the surface of our moon, the President of the United States once again challenged the nation to excel in space. Since that time, a series of outreach efforts was initiated by NASA to the aerospace industry, federal agencies, and the public. In addition, the Vice President of the United States chartered an Advisory Committee on the Future of the U.S. Space Program. At this writing, the AIAA has submitted a report on their canvass of the aerospace community, and the Advisory Committee report has been published. The synthesis group is in the conclusion preparation phase and should have the report completed by the time of this conference. Although each of these groups has taken different approaches, a consensus does appear that agrees with the President\u27s objectives. Whether the schedule or architectures agree, they all recommend a ...\u27 \u27balanced Space Program for America. We will, within budgetary limits, reenergize our country\u27s thrust into space through a renewed dedication toward the long-term magnet for the manned space program ... the human exploration of Mars. This, of course, is the long-term goal coupled with the science, mission-to-planet Earth, expanded technology and development of a robust space transportation system that make up the balanced program recommended. The authors do not disagree with the goals, objectives, or recommendations of the two reports published to date nor will we differ with the synthesis conclusions after they become apparent. We will briefly summarize the results of an .analysis conducted by McDonnell Douglas and Eagle Engineering in the second and third quarters of CY9Q. The results will show the benefits of space programs and suggest an overall approach to space architecture that could help maximize the world benefits of space while still meeting the overall objectives of the three sets of recommendations mentioned above. We acknowledge the work of the con- \u27 tributors to the AIAA report and to numerous NASA studies of specific endeavors such as the Lunar Energy Enterprise study. This paper is a much shortened version of the entire treatment. A more complete presentation will be available from the authors at the conference if desired

    Hardware interface unit for control of shuttle RMS vibrations

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    Vibration of the Shuttle Remote Manipulator System (RMS) increases the time for task completion and reduces task safety for manipulator-assisted operations. If the dynamics of the manipulator and the payload can be physically isolated, performance should improve. Rockwell has developed a self contained hardware unit which interfaces between a manipulator arm and payload. The End Point Control Unit (EPCU) is built and is being tested at Rockwell and at the Langley/Marshall Coupled, Multibody Spacecraft Control Research Facility in NASA's Marshall Space Flight Center in Huntsville, Alabama

    Paper Session III-C - Earth Dividends From the Development of Space Vehicle Robotics: Technologies and Techniques

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    This paper identifies and describes advanced robotics technologies and novel applications of state-of-the-art techniques which presently focus on space-related missions but which could result in other dividends on Earth. The paper has three sections. The first section focuses on the development of technology to help NASA automate the reprocessing of low-Earth-orbit vehicles. These advanced technologies include vibration isolation for robot arms and end-effectors, automated handling of fuels and other hazardous materials, and automated safety systems for process control. The second section describes the use of state-of-the-art solid modeling techniques to assist in the design of a robot arm, camera systems, sensors, and platforms for characterizing and exploring a planetary terrain. The third section discusses the use of these advanced technologies and novel applications to provide dividends on Earth in both space- and nonspacerelated applications. Vibration isolation could improve the performance of long manipulator arms used for vehicle processing and cleaning Department of Energy waste tanks. Automated handling of hazardous fluids could help automate the fueling of commercial and passenger vehicles. The advanced safety circuit could enhance many chemical process control operations. Modeling techniques for designing terrain exploration systems could assist the design of vehicles for exploring the many sites on Earth where human entry may be unsafe or inefficient, such as nuclear waste sites, military sites with unexploded ordnance, and widespread geological and agricultural surveys

    Paper Session I-C - Advanced Vision and Robotic Systems for Hazardous Environments

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    This paper describes work performed at the Rockwell Space Division, Downey, California, and at Fluor Daniel Inc. Irvine, California, related to task performance in remote hazardous environments through advanced robotic and vision systems. These environments could be in space, for example related to the Space Shuttle, Space Station and outer space and planetary environments. In addition, the environments could be on earth, for example areas contaminated by chemical or radioactive waste. In both instances, the task is most efficiently performed when the environment has been designed from the very beginning for remote task performance. While this is often not the case, much is being done in the development of two important related remote technologies: environmental characterization and inspection; and remote handling and manipulation. Important work has already taken place in developing robust systems for remote characterization, inspection and manipulation, for example, at the facilities of NASA and the Department of Energy. NASA is already integrating and testing a mobile robot system for inspection and re-waterproofing of thermal protection system tiles on the Space Shuttle. Other NASA efforts include micro-rovers, robotic devices for ground emergency responses, robots with local autonomy for ground characterization, and small, highly dexterous robots for visual inspection. In addition, the Department of Energy has many efforts to develop characterization, inspection and robotic systems for radiation areas. Notable examples include mobile systems for inspection of exterior and interior acreage sites, reactor vessels, pipes, drums, and various devices and special end-effectors for waste excavation, size reduction, manipulation, decontamination, and decommissioning. To support these activities, we have taken a systematic approach to developing some of the basic technologies necessary for remote operations in hostile environments. Our major thrust has been to develop a modular, re-configurable robotics laboratory test bed, and then to use this test bed to support advances in the following areas: simulation and engineering analysis for development and verification of remote tasks; special vision systems; and vibration isolation to stabilize and enhance remote manipulators

    Testing of an End-Point Control Unit Designed to Enable Precision Control of Manipulator-Coupled Spacecraft

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    This paper presents an end-point control concept designed to enable precision telerobotic control of manipulator-coupled spacecraft. The concept employs a hardware unit (end-point control unit EPCU) that is positioned between the end-effector of the Space Shuttle Remote Manipulator System and the payload. Features of the unit are active compliance (control of the displacement between the end-effector and the payload), to allow precision control of payload motions, and inertial load relief, to prevent the transmission of loads between the end-effector and the payload. This paper presents the concept and studies the active compliance feature using a simulation and hardware. Results of the simulation show the effectiveness of the EPCU in smoothing the motion of the payload. Results are presented from initial, limited tests of a laboratory hardware unit on a robotic arm testbed at the l Space Flight Center. Tracking performance of the arm in a constant speed automated retraction and extension maneuver of a heavy payload with and without the unit active is compared for the design speed and higher speeds. Simultaneous load reduction and tracking performance are demonstrated using the EPCU

    Conservation physiology can inform threat assessment and recovery planning processes for threatened species

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    Conservation physiology has emerged as a discipline with many success stories. Yet, it is unclear how it is currently integrated into the activities of the IUCN and other bodies which undertake international, national, or regional species threat assessments and work with partners to develop recovery plans. Here we argue that conservation physiology has much to offer for the threat assessment process and we outline the ways in which this can be operationalized. For instance, conservation physiology is effective in revealing causal relationships and mechanisms that explain observed patterns, such as population declines. Identifying the causes of population declines is a necessary precursor to the design of actions to reverse or mitigate such threats. Conservation physiology can also identify complex interactions and support modeling activities that consider emerging threats. When a population or species is deemed threatened and recovery plans are needed, physiology can be used to predict how organisms will respond to the conservation intervention and future threats. For example, if a recovery plan was focused on translocation, understanding how to safely translocate organisms would be necessary, as would ensuring that the recipient habitat provides the necessary environmental characteristics to meet the fundamental physiological needs/tolerances of that organism. Our hope is that this paper will clarify ways in which physiological data can make an important contribution to the conservation activities of bodies like the IUCN that are engaged in threat assess
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