System and method for automatically controlling a vehicle speed to a desired cruising speed
First Claim
1. A system for automatically controlling the speed of a vehicle at a target cruising speed, comprising:
- (a) first means for monitoring the speed of the vehicle;
(b) second means for setting the target cruising speed at which the vehicle cruises during a run of the vehicle according to a vehicle driver'"'"'s decision;
(c) third means for controlling the vehicular engine output according to a controlled variable set for each predetermined interval of time, so that the monitored vehicle speed coincides with the target cruising speed set by the second means;
(d) fourth means for storing a group of input/output membership functions for deriving the controlled variable in a fuzzy estimation, each stored membership function being correctable;
(e) fifth means for setting the controlled variable in the third means, using one of the membership functions retrieved from the fourth means on the basis of the monitored vehicle speed and the target cruising speed; and
(f) sixth means for deriving a change rate of the vehicle speed on the basis of the monitored vehicle speed and correcting any one or more of the membership functions stored in the fourth means and used for setting the controlled vehicle by the fifth means under a predetermined condition on the basis of the monitored vehicle speed and said set controlled variable.
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Accused Products
Abstract
A system for automatically controlling a vehicle speed to a desired cruising speed and method therefor are disclosed in which a controlled variable for an actuator for actuating a vehicular engine output to run the vehicle at the desired cruising speed is set using input and output membership functions for deriving an optimum operating variable of the actuator in a fuzzy estimation on the basis of input information on vehicle speed and a target cruising speed, the membership functions being stored in a memory and being correctable on the basis of the input information on the vehicle speed, change rates (control deviation, first-order difference, and second-order difference) of the vehicle speed, and set controlled variable, so that the vehicle speed conincides with the target cruising speed without reduction of control accuracy and without occurrence of overshooting of the controlled variable.
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Citations
21 Claims
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1. A system for automatically controlling the speed of a vehicle at a target cruising speed, comprising:
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(a) first means for monitoring the speed of the vehicle; (b) second means for setting the target cruising speed at which the vehicle cruises during a run of the vehicle according to a vehicle driver'"'"'s decision; (c) third means for controlling the vehicular engine output according to a controlled variable set for each predetermined interval of time, so that the monitored vehicle speed coincides with the target cruising speed set by the second means; (d) fourth means for storing a group of input/output membership functions for deriving the controlled variable in a fuzzy estimation, each stored membership function being correctable; (e) fifth means for setting the controlled variable in the third means, using one of the membership functions retrieved from the fourth means on the basis of the monitored vehicle speed and the target cruising speed; and (f) sixth means for deriving a change rate of the vehicle speed on the basis of the monitored vehicle speed and correcting any one or more of the membership functions stored in the fourth means and used for setting the controlled vehicle by the fifth means under a predetermined condition on the basis of the monitored vehicle speed and said set controlled variable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for automatically controlling the speed of a vehicle at a target cruising speed, comprising the steps of:
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(a) monitoring the vehicle speed; (b) setting a target cruising speed according to a driver'"'"'s decision; (c) providing means for storing a group of membership function in a fuzzy estimation, each stored membership function being correctable; (d) setting a controlled variable, using the membership functions stored in the step (c) and retrieved from the storing means on the basis of the monitored vehicle speed and the target cruising speed; (e) deriving a change of vehicle speed from the monitored vehicle speed and correcting the membership functions stored in the step (c) on the basis of input information of the monitored vehicle speed, the change rate of the vehicle speed and information on the controlled variable set in the step (d); and (f) controlling vehicular engine output according to the stored and corrected controlled variable in step (e) for each predetermined control period so that the monitored vehicle speed coincides with the target cruising speed. - View Dependent Claims (21)
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Specification