Adaptive cruise system
First Claim
Patent Images
1. An adaptive cruise control system for controlling the distance from a source vehicle to a target vehicle, the system comprising in combination:
- a speed sensor for sensing the speed VS of the source vehicle;
means for sensing the distance DA from the source vehicle to the target vehicle;
means adjustable by the source vehicle operator for providing a variable signal representing an operator reaction time Tr ;
means for determining an alert distance Dalert in accord with the expression
space="preserve" listing-type="equation">D.sub.alert =f(T.sub.r V.sub.S),where f(Tr VS) is a predetermined function including the term Tr VS ;
means for determining a desired trailing distance DD from the source vehicle to the target vehicle in accord with the expression
space="preserve" listing-type="equation">D.sub.D =D.sub.alert +Xwhere X is a constant distance;
means for determining a source vehicle command speed VC to establish the desired trailing distance DD ; and
means for controlling the speed of the source vehicle to the source vehicle command speed VC, whereby the speed of the source vehicle is controlled to maintain the distance to the target vehicle at the desired trailing distance DD that varies in accord with the adjustment of the driver reaction time by the source vehicle operator.
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Abstract
An adaptive cruise system for a vehicle maintains a desired selected operator-set speed in the absence of a detected preceding target vehicle and adjusts the vehicle speed when a target vehicle is detected to maintain a following distance that is set by the vehicle operator. An alert distance is computed that is a predetermined function of a distance based on driver reaction time. To provide for the driver selectable trailing distance, the driver reaction term of the alert distance is adjusted by the vehicle operator to achieve a desired distance to the target vehicle.
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Citations
4 Claims
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1. An adaptive cruise control system for controlling the distance from a source vehicle to a target vehicle, the system comprising in combination:
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a speed sensor for sensing the speed VS of the source vehicle; means for sensing the distance DA from the source vehicle to the target vehicle; means adjustable by the source vehicle operator for providing a variable signal representing an operator reaction time Tr ; means for determining an alert distance Dalert in accord with the expression
space="preserve" listing-type="equation">D.sub.alert =f(T.sub.r V.sub.S),where f(Tr VS) is a predetermined function including the term Tr VS ; means for determining a desired trailing distance DD from the source vehicle to the target vehicle in accord with the expression
space="preserve" listing-type="equation">D.sub.D =D.sub.alert +Xwhere X is a constant distance; means for determining a source vehicle command speed VC to establish the desired trailing distance DD ; and means for controlling the speed of the source vehicle to the source vehicle command speed VC, whereby the speed of the source vehicle is controlled to maintain the distance to the target vehicle at the desired trailing distance DD that varies in accord with the adjustment of the driver reaction time by the source vehicle operator. - View Dependent Claims (2)
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3. An adaptive cruise control system for controlling the distance from a source vehicle to a target vehicle, the system comprising in combination:
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a speed sensor for sensing the speed VS of the source vehicle; means for sensing the distance DA from the source vehicle to the target vehicle; means for sensing the relative velocity VR between the source vehicle and the target vehicle; means adjustable by the source vehicle operator for providing a variable signal representing an operator reaction time Tr ; means for determining an alert distance Dalert in accord with the expression
space="preserve" listing-type="equation">D.sub.alert =(V.sub.S.sup.2 /K.sub.1)-{(V.sub.S -V.sub.R).sup.2 /K.sub.2 56 +T.sub.r V.sub.S,where K1 and K2 are deceleration rate constants; means for determining a desired trailing distance DD from the source vehicle to the target vehicle in accord with the expression
space="preserve" listing-type="equation">D.sub.D =D.sub.alert +Xwhere X is a constant distance; means for determining a source vehicle command speed VC in accord with the expression
space="preserve" listing-type="equation">V.sub.C =K.sub.p (D.sub.D -D.sub.A)+(V.sub.S -V.sub.R)where Kp is a gain factor; and means for controlling the speed of the source vehicle to the source vehicle command speed VC, whereby the speed of the source vehicle is controlled to maintain the distance to the target vehicle at the desired trailing distance DD that varies in accord with the adjustment of the driver reaction time by the source vehicle operator.
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4. An adaptive cruise control method for controlling the distance from a source vehicle to a target vehicle, the system comprising the steps of:
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sensing the speed VS of the source vehicle; sensing the distance DA from the source vehicle to the target vehicle; sensing the relative velocity VR between the source vehicle and the target vehicle; providing an operator controlled signal representing an operator controlled reaction time Tr ; determining an alert distance Dalert in accord with the expression
space="preserve" listing-type="equation">D.sub.alert =(V.sub.S.sup.2 /K.sub.1)-{(V.sub.S -V.sub.R).sup.2 /K.sub.2 }+T.sub.r V.sub.S,where K1 and K2 are deceleration rate constants; determining a desired trailing distance DD from the source vehicle to the target vehicle in accord with the expression
space="preserve" listing-type="equation">D.sub.D =D.sub.alert +Xwhere X is a constant distance; determining a source vehicle command speed VC in accord with the expression
space="preserve" listing-type="equation">V.sub.C =K.sub.p (D.sub.D -D.sub.A)+(V.sub.S -V.sub.R)where Kp is a gain factor; and controlling the speed of the source vehicle to the source vehicle command speed VC, whereby the speed of the source vehicle is controlled to maintain the distance to the target vehicle at the desired trailing distance DD that varies in accord with the operator controlled reaction time.
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Specification