[en] High-speed analog devices that make use of the unique properties of superconducting tunnel junctions and transmission lines are finding application in microwave receivers, signal processors and voltage standards

[en] The design and control of long-reach, flexible manipulators has been an active research topic for over 20 years. Most of the research to date has focused on single link, fixed length, single plane of vibration test beds. In addition, actuation has been predominantly based upon electromagnetic motors. Ironically, these elements are rarely found in the existing industrial long-reach systems. One example is the Modified Light Duty Utility Arm (MLDUA) designed and built by Spar Aerospace for Oak Ridge National Laboratory (ORNL). This arm operates in larger, underground waste storage tanks located at ORNL. The size and nature of the tanks require that the robot have a reach of approximately 15 ft and a payload capacity of 250 lb. In order to achieve these criteria, each joint is hydraulically actuated. Furthermore, the robot has a prismatic degree-of-freedom to ease deployment. When fully extended, the robot's first natural frequency is 1.76 Hz. Many of the projected tasks, coupled with the robot's flexibility, present an interesting problem. How will many of the existing flexure control algorithms perform on a hydraulic, long-reach manipulator with prismatic links? To minimize cost and risk of testing these algorithms on the MLDUA, the authors have designed a new test bed that contains many of the same elements. This manuscript described a new hydraulically actuated, long-reach manipulator with a flexible prismatic link at ORNL. Focus is directed toward both modeling and control of hydraulic actuators as well as flexible links that have variable natural frequencies

[en] Published in summary form only

[en] This paper proposes and investigates an automated robot-based system for tile insertion of self-tapping screws into some unthreaded holes using Visual Servoing. As approximately a quarter of assembly operations in the manufacture of commercial products are screw insertions, therefore automation in this area is highly desirable. Research of the events occurring during the insertion of self-tapping screws has been largely neglected and automated system presently available do not provide adequate and reliable insertions. The focus of this paper is on the key stage of the insertion procedure i.e. detection of the insertion location by means of a Camera. The controller suggested is PD-type that includes an explicit nonlinear gravity compensation term in the control law. The advantageous point of the controller is that in spite of the disturbances; the controller is able to regulate the arm about the set-point solution. (author)

[en] This paper describes the application of the active flexible fixture (AFLEF) with passive RCC to the peg-in-hole task on the disk in the X-band accelerator. The AFLEF can fix any work and position the fixed work at short range. In this paper, the 2-dimensional AFLEF is proposed as the simplified type and is provided with passive RCC function to be equipped with dexterity for a peg-in-hole task. As results of the experiment on the peg-in-hole task on the X-band accelerator disks with the AFLEF, we make the ability of the AFLEF for the task clear and also the boundary conditions to the complete task clear. (author)

[en] This report describes the first known experimental study of servomanipulator duty cycles to appear in the literature. The servomanipulator used was TeleOperator Systems Model SM-229. The experimental approach used was to record the joint positions and motor currents of the right slave arm at a rate of 10 Hz over about 50 h of typical remote manipulation operations. The results are presented as position usage patterns in joint and real-world coordinates, time-use histograms of joint velocities and motor currents, and three-dimensional mechanical power histograms for each joint. All results are presented in dimensionless form, scaled to the design ranges of the manipulator and the total operation time recorded. Applications of this study include improvements in kinematic ranges, gear reductions, motor sizings, drive configurations, and stress relief. Included in appendices are an uncertainty analysis, calibration procedures, and analysis of the kinematics of the manipulator. 12 refs., 42 figs., 15 tabs

[en] Buck converters are widely used in switch mode power supplies due to their high efficiency, fast switching actions, low volume and weight, and low cost. These converters are variable structure systems and contain nonlinearities which lead to oscillations during operation. Various Control techniques have been investigated and analyzed in order to minimize oscillations during the operation of the converter, in particular, under non-linear situations. In this paper, an attempt is being made to control the oscillation of the buck converter by using sliding mode controller. The SMC (Sliding Mode Controller) is a nonlinear controller which can handle nonlinearities, provides good dynamic response and simple implementation. The proposed control scheme is implemented and simulated in MATLAB/Simulink. The results of SMC are compared with cascade controller and are presented in this paper. (author)

[en] The feasibility of incorporating safety functions into a sophisticated model-based control (MBC) system has been demonstrated. It is being utilized as a basis for advanced safing (detection and safe response to abnormal conditions) for robotic manipulators without the use of special sensors. An MBC-based safing system provides for rapid detection of collisions and changes in payload and may be applied to the detection of numerous additional conditions. This work demonstrates through an experimental robotic system that real-time MBC is feasible and suitable for manipulator safing

[en] Most of the research related to flexible link manipulators to date has focused on single link, fixed length, single plane of vibration test beds. In addition, actuation has been predominantly based upon electromagnetic motors. Ironically, these elements are rarely found in the existing industrial long reach systems. This manuscript describes a new hydraulically actuated, long reach manipulator with a flexible prismatic link at Oak Ridge National Laboratory (ORNL). Focus is directed towards both modeling and control of hydraulic actuators as well as flexible links that have variable natural frequencies

[en] A contact-less decentralized power supply is proposed with communication capability through only one transformer. A prototype of wireless transmission system of power and information (WTPI system) was built, and the two axis position control for servo motors was achieved by transferring the power and signal through one rotatable high frequency transformer. The proposed concept can be applied for robotics and NC machines