US 8,577,552 B1 · Forward collision warning system with road-side target filtering

Abstract

A method of filtering/rejecting targets detected by a forward collision warning system of a motor vehicle when entering a curved road segment. The width of a collision threat zone (CTZ) is reduced in one or more stages depending upon continuously-measured values of steering input angle (SIA), driver brake application (DBA), and a yaw rate. The measured values are used to find: a degree of near-past DBA variation during a first look-back period, a degree of near-past SIA change rate during a second look-back period, and a degree of far-past yaw rate change during a third look-back period longer than the first and the second look-back periods. A series of first, second and third width reductions of decreasing severity are applied to the CTZ based upon comparisons of the tracked variations and change rates with respective thresholds. The thresholds are tunable to achieve desired levels or false-target rejection.

Claims20

Dependent claims

A method of forward collision warning for a motor vehicle comprising:

operating a sensor system to detect a target ahead of the vehicle;
identifying a Collision Threat Zone (CTZ) along a predicted path of the vehicle;
continuously measuring a steering input angle (SIA) change rate and a yaw rate of the vehicle;
continuously tracking a near-past maximum absolute value of the SIA change rate during a first look-back period;
continuously tracking a far-past variation of the yaw rate during a second look-back period longer than the first look-back period;
applying a first width-reduction to at least a portion of the CTZ in the event that a) the near-past maximum absolute value of SIA change rate exceeds a first SIA change rate threshold, and
b) the far-past variation of yaw rate exceeds a first yaw rate threshold value;
and
suppressing a threat warning based on detection of the target if the target is outside of the CTZ with the first width-reduction applied.

6 more elements

A method comprising:

operating a forward collision warning sensor of a motor vehicle to detect a target ahead of the vehicle;
identifying a collision threat zone (CTZ) ahead of the vehicle in which the target is considered a collision threat, the CTZ having a base width;
continuously measuring a steering input angle (SIA) change rate, a driver brake application (DBA), and a yaw rate;
finding a degree of near-past DBA during a first look-back period;
finding a degree of near-past SIA change rate during a second look-back period;
finding a degree of far-past yaw rate during a third look-back period longer than the first and the second look-back periods;
applying a first width reduction to the CTZ if either 1) the near past SIA change rate exceeds a peak SIA change rate threshold, or 2) the near-past DBA indicates braking and either a) the near past SIA change rate exceeds a second SIA change rate threshold lower than the peak SIA change rate threshold or b) the far-past yaw rate exceeds a first yaw rate threshold;
and
suppressing a threat warning if the target is outside of the CTZ with the first width reduction applied.

6 more elements

Dependencies are inferred from the claim text.

Forward collision warning system with road-side target filtering

Life of this patent

Forward collision warning system with road-side target filtering

Life of this patent

Abstract

Claims20