1,034 research outputs found

    Connector pin and method

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    An electrical connector and method includes a connector and a conforming element proximate to or in contact with the mating end of the connector so as to prevent distortion of a matable end. The matable end of the connector may be of a female or male type and may be of a post, tube, blade, pin, or other configuration. An element made of conforming material, for example, an elastomer, epoxy or rubber type material, is configured and positioned in contact with the matable end of the connector, providing support during assembly to prevent distortion of the matable end. The conforming element may be rectangular, wedge, cylindrical, conical, annular, or of another configuration as required to provide support to the connector pin. The conforming element may be fastened with an adhesive to the matable end to further prevent distortion

    System and method for calibrating a rotary absolute position sensor

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    A system includes a rotary device, a rotary absolute position (RAP) sensor generating encoded pairs of voltage signals describing positional data of the rotary device, a host machine, and an algorithm. The algorithm calculates calibration parameters usable to determine an absolute position of the rotary device using the encoded pairs, and is adapted for linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters. A method of calibrating the RAP sensor includes measuring the rotary position as encoded pairs of voltage signals, linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters, and calculating an absolute position of the rotary device using the calibration parameters. The calibration parameters include a positive definite matrix (A) and a center point (q) of the ellipse. The voltage signals may include an encoded sine and cosine of a rotary angle of the rotary device

    Integrated High-Speed Torque Control System for a Robotic Joint

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    A control system for achieving high-speed torque for a joint of a robot includes a printed circuit board assembly (PCBA) having a collocated joint processor and high-speed communication bus. The PCBA may also include a power inverter module (PIM) and local sensor conditioning electronics (SCE) for processing sensor data from one or more motor position sensors. Torque control of a motor of the joint is provided via the PCBA as a high-speed torque loop. Each joint processor may be embedded within or collocated with the robotic joint being controlled. Collocation of the joint processor, PIM, and high-speed bus may increase noise immunity of the control system, and the localized processing of sensor data from the joint motor at the joint level may minimize bus cabling to and from each control node. The joint processor may include a field programmable gate array (FPGA)

    Method and apparatus for electromagnetically braking a motor

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    An electromagnetic braking system and method is provided for selectively braking a motor using an electromagnetic brake having an electromagnet, a permanent magnet, a rotor assembly, and a brake pad. The brake assembly applies when the electromagnet is de-energized and releases when the electromagnet is energized. When applied the permanent magnet moves the brake pad into frictional engagement with a housing, and when released the electromagnet cancels the flux of the permanent magnet to allow a leaf spring to move the brake pad away from the housing. A controller has a DC/DC converter for converting a main bus voltage to a lower braking voltage based on certain parameters. The converter utilizes pulse-width modulation (PWM) to regulate the braking voltage. A calibrated gap is defined between the brake pad and permanent magnet when the brake assembly is released, and may be dynamically modified via the controller

    Forming Human-Robot Teams Across Time and Space

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    NASA pushes telerobotics to distances that span the Solar System. At this scale, time of flight for communication is limited by the speed of light, inducing long time delays, narrow bandwidth and the real risk of data disruption. NASA also supports missions where humans are in direct contact with robots during extravehicular activity (EVA), giving a range of zero to hundreds of millions of miles for NASA s definition of "tele". . Another temporal variable is mission phasing. NASA missions are now being considered that combine early robotic phases with later human arrival, then transition back to robot only operations. Robots can preposition, scout, sample or construct in advance of human teammates, transition to assistant roles when the crew are present, and then become care-takers when the crew returns to Earth. This paper will describe advances in robot safety and command interaction approaches developed to form effective human-robot teams, overcoming challenges of time delay and adapting as the team transitions from robot only to robots and crew. The work is predicated on the idea that when robots are alone in space, they are still part of a human-robot team acting as surrogates for people back on Earth or in other distant locations. Software, interaction modes and control methods will be described that can operate robots in all these conditions. A novel control mode for operating robots across time delay was developed using a graphical simulation on the human side of the communication, allowing a remote supervisor to drive and command a robot in simulation with no time delay, then monitor progress of the actual robot as data returns from the round trip to and from the robot. Since the robot must be responsible for safety out to at least the round trip time period, the authors developed a multi layer safety system able to detect and protect the robot and people in its workspace. This safety system is also running when humans are in direct contact with the robot, so it involves both internal fault detection as well as force sensing for unintended external contacts. The designs for the supervisory command mode and the redundant safety system will be described. Specific implementations were developed and test results will be reported. Experiments were conducted using terrestrial analogs for deep space missions, where time delays were artificially added to emulate the longer distances found in space

    Lattice dynamics and correlated atomic motion from the atomic pair distribution function

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    The mean-square relative displacements (MSRD) of atomic pair motions in crystals are studied as a function of pair distance and temperature using the atomic pair distribution function (PDF). The effects of the lattice vibrations on the PDF peak widths are modelled using both a multi-parameter Born von-Karman (BvK) force model and a single-parameter Debye model. These results are compared to experimentally determined PDFs. We find that the near-neighbor atomic motions are strongly correlated, and that the extent of this correlation depends both on the interatomic interactions and crystal structure. These results suggest that proper account of the lattice vibrational effects on the PDF peak width is important in extracting information on static disorder in a disordered system such as an alloy. Good agreement is obtained between the BvK model calculations of PDF peak widths and the experimentally determined peak widths. The Debye model successfully explains the average, though not detailed, natures of the MSRD of atomic pair motion with just one parameter. Also the temperature dependence of the Debye model largely agrees with the BvK model predictions. Therefore, the Debye model provides a simple description of the effects of lattice vibrations on the PDF peak widths.Comment: 9 pages, 11 figure

    Indonesia Governance Index 2012: Towards a Well-informed Society and Responsive Government

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    Regional autonomy aims not only to increase welfare through provision of quality public services, but also to allow regions to determine their own development priorities. As a result, there is a range of different capacities and standards between local administrations and other stakeholders, leading to widening gaps in development between regions. Efforts to improve are limited by the analytical capacity and the quality of governance in each location. Because of this we need an objective assessment of governance and Kemitraan has adressed this need with the Indonesia Governance Index (IGI). This book examines the national findings of the 2012 IGI research, and offers concrete suggestions to solve current problems. It also elaborates on the results in key areas like gender, investment friendliness, and environmental management

    Proceedings from the National Cancer Institute’s Second International Workshop on the Biology, Prevention, and Treatment of Relapse after Hematopoietic Stem Cell Transplantation: Part III. Prevention and treatment of relapse after allogeneic transplantation

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    AbstractIn the Second Annual National Cancer Institute’s Workshop on the Biology, Prevention, and Treatment of Relapse after Hematopoietic Stem Cell Transplantation, the Scientific/Educational Session on the Prevention and Treatment of Relapse after Allogeneic Transplantation highlighted progress in developing new therapeutic approaches since the first relapse workshop. Recent insights that might provide a basis for the development of novel, practical clinical trials were emphasized, including utilization of newer agents, optimization of donor lymphocyte infusion (DLI), and investigation of novel cellular therapies. Dr. de Lima discussed pre-emptive and maintenance strategies to prevent relapse after transplantation, for example, recent promising results suggestive of enhanced graft-versus-tumor activity with hypomethylating agents. Dr. Schmid provided an overview of adjunctive strategies to improve cell therapy for relapse, including cytoreduction before DLI, combination of targeted agents with DLI, and considerations in use of second transplantations. Dr. Porter addressed strategies to enhance T cell function, including ex vivo activated T cells and T cell engineering, and immunomodulatory approaches to enhance T cell function in vivo, including exogenous cytokines and modulation of costimulatory pathways

    Rotary Series Elastic Actuator

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    A rotary actuator assembly is provided for actuation of an upper arm assembly for a dexterous humanoid robot. The upper arm assembly for the humanoid robot includes a plurality of arm support frames each defining an axis. A plurality of rotary actuator assemblies are each mounted to one of the plurality of arm support frames about the respective axes. Each rotary actuator assembly includes a motor mounted about the respective axis, a gear drive rotatably connected to the motor, and a torsion spring. The torsion spring has a spring input that is rotatably connected to an output of the gear drive and a spring output that is connected to an output for the joint
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