20,860 research outputs found

    Integration of a computerized two-finger gripper for robot workstation safety

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    A microprocessor-based controller has been developed that continuously monitors and adjusts the gripping force applied by a special two-finger gripper. This computerized force sensing gripper system enables the endeffector gripping action to be independently detected and corrected. The gripping force applied to a manipulated object is real-time monitored for problem situations, situations which can occur during both planned and errant robot arm manipulation. When unspecified force conditions occur at the gripper, the gripping force controller initiates specific reactions to cause dynamic corrections to the continuously variable gripping action. The force controller for this intelligent gripper has been interfaced to the controller of an industrial robot. The gripper and robot controllers communicate to accomplish the successful completion of normal gripper operations as well as unexpected hazardous situations. An example of an unexpected gripping condition would be the sudden deformation of the object being manipulated by the robot. The capabilities of the interfaced gripper-robot system to apply workstation safety measures (e.g., stop the robot) when these unexpected gripping effects occur have been assessed

    Remotely operated gripper provides vertical control rod movement

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    Remote actuation of a gripper shaft affects vertical engagement between a drive shaft and control rod. A secondary function of the gripper is to provide remote indication of positive completion of the gripping or ungripping operation

    The margin and the mainstream : positioning Harry Partch's theories within the broader discourse of musical aesthetics

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    Bibliography: leaves 102-106.The dissertation examines the broader musical value of microtonal composer Harry Partch's musical theories by locating his critique of abstract music within mainstream compositional theory and aesthetics. This contextualisation aims to deconstruct Partch's iconoclastic image so as to understand his contribution within a wider realm of critical discourse. The work of composers that follow in Partch's footsteps becomes important in this context, especially that of his one-time student Ben Johnston whose own microtonal aesthetic is firmly rooted in European aesthetics from Debussy to Schoenberg. By a study of Johnston's utilisation of Partch's theory of just intonation the dissertation attempts to arrive at a more inclusive compositional theory, one which continues to address those aspects of Partch's theories that serve as a valid and constructive critique of traditional musical values. Taking Adorno's view that musical critique must deal with the problem of reification at the level of musical materials, the author proposes a reading of Partch's corporeal philosophy that is applicable beyond the confines of narrative musical drama. By creating a distinction between historical models of organisation and 'second nature' forms of musical presentation, it is suggested that critique does not necessarily prefigure alienation from the mainstream, but can rather be situated within musical discourse in such a way that a new image of the latter's forms results. On a practical level, the dissertation explores the validity of expanded just intonation as a means of achieving this immanent critique, both in the realm of compositional theory and, implicitly, in that of analytical theory, concluding with the description of a tuning system with the capacity to synthesise the range of compositional theories explored

    Design of an auto change mechanism and intelligent gripper for the space station

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    Robot gripping of objects in space is inherently demanding and dangerous and nowhere is this more clearly reflected than in the design of the robot gripper. An object which escapes the gripper in a micro g environment is launched not dropped. To prevent this, the gripper must have sensors and signal processing to determine that the object is properly grasped, e.g., grip points and gripping forces and, if not, to provide information to the robot to enable closed loop corrections to be made. The sensors and sensor strategies employed in the NASA/GSFC Split-Rail Parallel Gripper are described. Objectives and requirements are given followed by the design of the sensor suite, sensor fusion techniques and supporting algorithms

    Real time control for NASA robotic gripper

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    Control laws (in some optimal sense) are being developed for the gripper/nut runner end effector. Control laws for the gripper and nut runner portions of the end effector may be developed independently since these two systems are decoupled. A hybrid force/position controller will be used for both the gripper and nut runner. The development of the gripper controller is explained. Sensory data available to the controller is obtained from an array of strain gages as well as a linear potentiometer. Applying well known optimal control theoretic principles, the control which minimizes the transition time between positions is obtained. In addition, a robust force control scheme is developed to contend with the strain gage drift caused by extreme temperature variations encountered in space

    Global Innovations in Measurement and Evaluation

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    We researched the latest developments in theory and practice in measurement and evaluation. And we found that new thinking, techniques, and technology are influencing and improving practice. This report highlights 8 developments that we think have the greatest potential to improve evaluation and programme design, and the careful collection and use of data. In it, we seek to inform and inspire—to celebrate what is possible, and encourage wider application of these ideas

    The KIT swiss knife gripper for disassembly tasks: a multi-functional gripper for bimanual manipulation with a single arm

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    © 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This work presents the concept of a robotic gripper designed for the disassembly of electromechanical devices that comprises several innovative ideas. Novel concepts include the ability to interchange built-in tools without the need to grasp them, the ability to reposition grasped objects in-hand, the capability of performing classic dual arm manipulation within the gripper and the utilization of classic industrial robotic arms kinematics within a robotic gripper. We analyze state of the art grippers and robotic hands designed for dexterous in-hand manipulation and extract common characteristics and weak points. The presented concept is obtained from the task requirements for disassembly of electromechanical devices and it is then evaluated for general purpose grasping, in-hand manipulation and operations with tools. We further present the CAD design for a first prototype.Peer ReviewedPostprint (author's final draft
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