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US 8,078,383 B2Granted
Speed control system for vehicles
AssigneeDenso Corporation
InventorsKazuyoshi Isaji, Naohiko Tsuru
Life of this patent
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Abstract
In a vehicle speed control system, a preset offset distance is taken as a zero value of an inter-vehicle distance in a brake discriminant. When the current value of a corrected distance condition evaluation index is higher than the brake discriminant, a value on the brake discriminant is set as a target value of the corrected distance condition evaluation index. Deceleration control is started to decelerate the subject vehicle so that the deceleration of the subject vehicle becomes equal to the target deceleration of the subject vehicle computed based on the target relative speed corresponding to the set target value and the actual relative speed.
Claims18
A speed control system for vehicles comprising:
- means for detecting a distance to a preceding vehicle;
- means for detecting a relative speed between a subject vehicle and the preceding vehicle;
- means for computing a corrected distance condition evaluation index which is increased with increase in the relative speed when approaching the preceding vehicle and whose increase gradient becomes greater as the distance to the preceding vehicle becomes shorter at each relative speed as an index indicating the condition of approaching or separating from the preceding vehicle by taking into consideration of a speed of the preceding vehicle;
- first means for setting a threshold value of the corrected distance condition evaluation index and taking an offset amount preset with respect to distance as zero value of distance at the threshold value of the corrected distance condition evaluation index;
- means for checking whether the corrected distance condition evaluation index is higher than the threshold value of the corrected distance condition evaluation index;
- second means for setting the threshold value of the corrected distance condition evaluation index as a target value of the corrected distance condition evaluation index when the corrected distance condition evaluation index is higher than the threshold value of the corrected distance;
- means for computing the target deceleration of the subject vehicle based on a target relative speed corresponding to the target value set by the means for setting the threshold value as the target value and an actual relative speed;
- and
- means for starting deceleration control to decelerate the subject vehicle so that deceleration of the subject vehicle becomes equal to the target deceleration.
6 more elements
A speed control system for vehicles comprising:
- means for detecting a distance to an object ahead;
- means for detecting a relative speed between a subject vehicle and the object ahead;
- means for storing a correction formula for computation of a corrected target relative speed obtained by correcting a formula for computation of a target relative speed with an offset amount indicating the target relative speed when the distance is zero,
- wherein the formula for computation of target relative speed is determined from a distance condition evaluation index relational expression and a tangential expression so that a target relative speed is determined based on the distance,
- wherein, the distance condition evaluation index relational expression indicates a relation among the distance condition evaluation index indicating condition of distance to the object ahead, a distance to the object ahead and the relative speed, so that the distance condition evaluation index is increased with increase in the relative speed when approaching the object ahead and an increase gradient of the distance condition evaluation index becomes greater as the distance to the object ahead becomes shorter at identical relative speed, and
- wherein the tangential expression indicates a tangent of a curve represented by the distance condition evaluation index relational expression, and is determined by differentiating the distance condition evaluation index relational expression by the distance, thereby indicating a relation between the distance condition evaluation index and the distance;
- means for computing a target relative speed from the correction formula for computation of target relative speed and a distance actually detected by the means for detecting the distance;
- means for computing a target deceleration from a target relative speed computed by the means for computing a target relative speed and a relative speed actually detected by the means for detecting the relative speed;
- and
- means for performing deceleration control on the subject vehicle based on the target deceleration.
7 more elements
A speed control system for vehicles comprising:
- means for detecting a distance to an object ahead;
- means for detecting a relative speed between a subject vehicle and the object ahead;
- means for storing a correction formula for computation of a corrected target relative speed obtained by correcting a formula for computation of a target relative speed with an offset amount indicating the distance when the relative speed is zero,
- wherein the formula for computation of target relative speed is determined from a distance condition evaluation index relational expression and a tangential expression so that a target relative speed is determined based on the distance,
- wherein, the distance condition evaluation index relational expression indicates a relation among the distance condition evaluation index indicating condition of distance to the object ahead, a distance to the object ahead and the relative speed, so that the distance condition evaluation index is increased with increase in the relative speed when approaching the object ahead and an increase gradient of the distance condition evaluation index becomes greater as the distance to the object ahead becomes shorter at identical relative speed, and
- wherein the tangential expression indicates a tangent of a curve represented by the distance condition evaluation index relational expression, and is determined by differentiating the distance condition evaluation index relational expression by the distance, thereby indicating a relation between the distance condition evaluation index and the distance;
- means for computing a target relative speed from the correction formula for computation of target relative speed and a distance actually detected by the means for detecting the distance;
- means for computing a target deceleration from a target relative speed computed by the means for computing a target relative speed and a relative speed actually detected by the means for detecting the relative speed;
- and
- means for performing deceleration control on the subject vehicle based on the target deceleration.
7 more elements
Dependencies are inferred from the claim text.