61 lines
3.2 KiB
Plaintext
61 lines
3.2 KiB
Plaintext
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Excerpt from Computer Design
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April 1992
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NASA EYES RANGE OF FUZZY CONTROL IDEAS IN SPACE
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NASA has recently reported encouraging research results in a
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number of areas using fuzzy logic. One of the most advanced
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projects is a controller for space shuttle proximity operations,
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i.e. maneuvering around or keeping position with respect to
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another object in space. Work has been progressing on a fuzzy-
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based translational controller which deals with the parameters
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of azimuth and angle and their respective rates of change, and
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the range and rate of change of range with respect to another
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object.
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NASA engineers developed natural language rules to run the
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controller and are testing it in a multi-vehicle simulation by
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substituting the fuzzy controller for the simulator's normal
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human inputs. The rule base was learned from the experience of
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human operators and the efficiency of the controller was tuned
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based on flight profiles recorded from actual missions and
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simulations. One of the main advantages in developing the fuzzy
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translational controller were that the engineers did not need to
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construct a detailed mathematical model of the system in
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advance. Performance was honed through simulation and
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experience.
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The results of simulations have been encouraging, especially in
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terms of fuel efficiency. In holding position with respect to
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a target, the fuzzy controller required significantly less
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acceleration (i.e. smaller increments of position change) than
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did the human controlled simulation. In overall maneuvers, the
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fuzzy controller has shown a 20% to 70% better fuel efficiency
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than the currently used digital auto pilot and the best
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simulation runs of human pilots.
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NASA is also exploring other applications of fuzzy control in
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space. Among the projects being considered are the use of
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inexpensive cameras for constant tracking of objects around the
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space station, fuzzy control can contribute to collision
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avoidance systems, robot arm control and traffic management.
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At the great distance of interplanetary space where it can take
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20 minutes to send a signal and receive an answer, robotic
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systems will have to operate quasi-independently. A fuzzy
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controller on an unmanned Mars rover vehicle is expected to help
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the rover avoid obstacles and identify and collect soil samples
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based on imprecise sensor input and only partially known
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conditions.
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------------------------------------------------------------
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This is article is provided with permission from Computer
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Design. For subscription information to Computer Design, call
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Paul Westervelt at (913) 835-3161. Do not redistribute in
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an form (written or electronic) without permission from
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Computer Design.
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This is information is provided by
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Aptronix FuzzyNet
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408-428-1883 Data USR V.32bis
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