389 research outputs found
Traction-drive force transmission for telerobotic joints
A mechanism which meets the requirements of a teleoperated manipulator and those of an autonomous robot is discussed. The mechanism is a traction-drive differential that uses variable preload mechanisms. The differential provides compact design, with dextrous motion range and torque density similar to geared systems. The traction drive offers high stiffness to backlash for good robotic performance. The variable-loading mechanism (VLM) minimizes the drive-train friction for improved teleoperation. This combination provides a mechanism to allow advanced manipulation with either teleoperated control or autonomous robotic operation. The design principles of both major components of the joint mechanism are described
Dual arm master controller development
The advanced servomanipulator (ASM) slave was designed with an anthropomorphic stance gear/torque tube power drives, and modular construction. These features resulted in increased inertia, friction, and backlash relative to tape driven manipulators. Studies were performed which addressed to human factor design and performance tradeoffs associated with the corresponding master controller best suited for the ASM. The results of these studies, as well as the conceptual design of the dual arm master controller, are presented
Unexpected crossover dynamics of single polymer in a corrugated tube
We present molecular dynamics study of a generic (coarse-grained) model for
single-polymer diffusion confined in a corrugated cylinder. For a narrow tube,
i.e., diameter of the cylinder , the axial diffusion coefficient
scales as , with chain length , up to then crosses over to Rouse scaling for the larger values. The
scaling is due to the large fluctuation of the polymer chain along
its fully stretched equilibrium conformation. The stronger scaling, namely
, is not observed for an atomistically smooth tube and/or for a
cylinder with larger diameter.Comment: 10 pages, 3 figures, LaTeX, version accepted by J. Chem. Phy
Operational experience and design recommendations for teleoperated flight hardware
Teleoperation (remote manipulation) will someday supplement/minimize astronaut extravehicular activity in space to perform such tasks as satellite servicing and repair, and space station construction and servicing. This technology is being investigated by NASA with teleoperation of two space-related tasks having been demonstrated at the Oak Ridge National Lab. The teleoperator experiments are discussed and the results of these experiments are summarized. The related equipment design recommendations are also presented. In addition, a general discussion of equipment design for teleoperation is also presented
Traction-drive, seven-degree-of-freedom telerobot arm: A concept for manipulaton in space
As man seeks to expand his dominion into new environments, the demand increases for machines that perform useful functions in remote locations. This new concept for manipulation in space is based on knowledge and experience gained from manipulator systems developed to meet the needs of remote nuclear applications. It merges the best characteristics of teleoperation and robotic technologies. The design goals for the telerobot, a mechanical description, and technology areas that must be addressed for successful implementation are presented and discussed. The concept incorporates mechanical traction drives, redundant kinematics, and modular arm subelements to provide a backlash-free manipulator capable of obstacle avoidance
Minimally Invasive Therapies for Hepatocellular Carcinoma: Mechanisms of Local Control and Systemic Immunologic Response
Minimally invasive treatments for hepatocellular carcinoma (HCC) are a cornerstone in the management of this challenging disease. For many years, percutaneously guided ablative techniques, such as radiofrequency ablation (RFA), cryoablation, and microwave ablation (MWA), have successfully treated many different solid malignancies including HCC. Since the initial implementation of these ablative techniques, there have been many advances in the design, technique, and patient selection as well as investigation into the body’s response to treatment. The mechanisms of thermal-based ablative techniques, advantages and disadvantages of each technique, subsequent immunologic response following ablation, and advances in care that utilize combination therapy to potentiate the immunologic response creating a robust and long-term immunity to HCC are outlined in this chapter
Omniview motionless camera orientation system
An apparatus and method is provided for converting digital images for use in an imaging system. The apparatus includes a data memory which stores digital data representing an image having a circular or spherical field of view such as an image captured by a fish-eye lens, a control input for receiving a signal for selecting a portion of the image, and a converter responsive to the control input for converting digital data corresponding to the selected portion into digital data representing a planar image for subsequent display. Various methods include the steps of storing digital data representing an image having a circular or spherical field of view, selecting a portion of the image, and converting the stored digital data corresponding to the selected portion into digital data representing a planar image for subsequent display. In various embodiments, the data converter and data conversion step may use an orthogonal set of transformation algorithms
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Traction-drive seven degrees-of-freedom telerobot arm: A concept for manipulation in space
As man seeks to expand his dominion into new environments, the demand increases for machines that perform useful functions in remote locations. This new concept for manipulation in space is based on knowledge and experience gained from manipulator systems developed to meet the needs of remote nuclear applications. It merges the best characteristics of teleoperation and robotic technologies. This paper summarizes the report of a study performed for NASA Langley Research Center. The design goals for the telerobot, a mechanical description, and technology areas that must be addressed for successful implementation will be presented and discussed. The concept incorporates mechanical traction drives, redundant kinematics, and modular arm subelements to provide a backlash-free manipulator capable of obstacle avoidance. Further development of this arm is in progress at the Oak Ridge National Laboratory
The laboratory telerobotic manipulator program
New opportunities for the application of telerobotic systems to enhance human intelligence and dexterity in the hazardous environment of space are presented by the NASA Space Station Program. Because of the need for significant increases in extravehicular activity and the potential increase in hazards associated with space programs, emphasis is being heightened on telerobotic systems research and development. The Laboratory Telerobotic Manipulator (LTM) program is performed to develop and demonstrate ground-based telerobotic manipulator system hardware for research and demonstrations aimed at future NASA applications. The LTM incorporates traction drives, modularity, redundant kinematics, and state-of-the-art hierarchical control techniques to form a basis for merging the diverse technological domains of robust, high-dexterity teleoperations and autonomous robotic operation into common hardware to further NASA's research
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Advanced remotely maintainable force-reflecting servomanipulator concept
A remotely maintainable force-reflecting servomanipulator concept is being developed at the Oak Ridge National Laboratory as part of the Consolidated Fuel Reprocessing Program. This new manipulator addresses requirements of advanced nuclear fuel reprocessing with emphasis on force reflection, remote maintainability, reliability, radiation tolerance, and corrosion resistance. The advanced servomanipulator is uniquely subdivided into remotely replaceable modules which will permit in situ manipulator repair by spare module replacement. Manipulator modularization and increased reliability are accomplished through a force transmission system that uses gears and torque tubes. Digital control algorithms and mechanical precision are used to offset the increased backlash, friction, and inertia resulting from the gear drives. This results in the first remotely maintainable force-reflecting servomanipulator in the world. 10 references, 4 figures, 1 table
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