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Sensor-Based Collision Avoidance: Theory and ExperimentsA new on-line control strategy for sensor-based collision avoidance of manipulators and supporting experimental results are presented in this article. This control strategy is based on nullification of virtual forces applied to the end-effector by a hypothetical spring-plus-damper attached to the object's surface. In the proposed approach, the real-time arm control software continuously monitors the object distance measured by the arm-mounted proximity sensors. When this distance is less than a preset threshold, the collision avoidance control action is initiated to inhibit motion toward the object and thus prevent collision. This is accomplished by employing an outer feedback loop to perturb the end-effector nominal motion trajectory in real-time based on the sensory data. The perturbation is generated by a proportional-plus-integral (PI) collision avoidance controller acting on the difference between the sensed distance and the preset threshold. This approach is computationally very fast, requires minimal modification to the existing manipulator positioning system, and provides the manipulator with an on-line collision avoidance capability to react autonomously and intelligently. A dexterous RRC robotic arm is instrumented with infrared proximity sensors and is operated under the proposed collision avoidance strategy. Experimental results are presented to demonstrate end-effector collision avoidance both with an approaching object and while reaching inside a constricted opening.
Document ID
19990019473
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Seraji, Homayoun
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Steele, Robert
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Ivlev, Robert
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1996
Publication Information
Publication: Journal of Robotic Systems
Publisher: Wiley (John) and Sons, Inc.
Volume: 13
Issue: 9
ISSN: 0741-2223
Subject Category
Cybernetics
Distribution Limits
Public
Copyright
Other

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