Trailer sway warning system and method
A trailer sway warning system, according to one embodiment, includes a hitch angle sensor for sensing a hitch angle between a vehicle and a trailer. The trailer sway warning system includes a vehicle sensor for sensing a dynamic parameter of the vehicle, such as a steering angle rate or a yaw rate of the vehicle. Further, the trailer sway warning system includes a controller that generates a warning signal when the hitch angle is oscillating at a magnitude that exceeds a warning threshold and the dynamic parameter is substantially constant.
1. A trailer sway warning system, comprising:
a hitch angle sensor for sensing a hitch angle between a vehicle and a trailer;
a vehicle sensor for sensing a dynamic parameter of the vehicle; and
a controller generating a warning signal when the dynamic parameter is constant and the hitch angle is oscillating at a magnitude that exceeds a warning threshold, wherein the warning signal is deactivated when the magnitude of oscillation of the hitch angle is reduced below a second threshold that is less than the warning threshold.
2. The trailer sway warning system of claim 1 , wherein the vehicle sensor comprises a yaw rate sensor for sensing a yaw rate of the vehicle, and wherein the warning signal is generated when the yaw rate is substantially constant.
3. The trailer sway warning system of claim 2 , wherein the yaw rate is substantially constant when steered wheels of the vehicle are held at a constant angle.
4. The trailer sway warning system of claim 1 , wherein the vehicle sensor comprises a steering angle sensor for sensing a steering angle rate of the vehicle, and wherein the warning signal is generated when the steering angle rate is substantially zero.
5. The trailer sway warning system of claim 4 , wherein the magnitude of oscillation of the hitch angle is determined by the amount the hitch angle fluctuates about a zero hitch angle that coincides with a centerline longitudinal axis of the vehicle in alignment with a tongue of the trailer.
6. The trailer sway warning system of claim 4 , wherein the steering angle rate is substantially zero when steered wheels of the vehicle are held at a substantially constant angle.
7. The trailer sway warning system of claim 1 , wherein the controller generates a braking command for the vehicle to reduce the magnitude of oscillation of the hitch angle when the warning signal is generated for a select duration of time.
8. The trailer sway warning system of claim 1 , wherein the hitch angle sensor comprises a vision-based sensor on the vehicle that monitors a position of the trailer relative to the vehicle for determining the hitch angle.
9. The trailer sway warning system of claim 1 , further comprising:
a display for showing a visible warning when the warning signal is generated.
10. A trailer sway warning system, comprising:
a hitch angle sensor sensing a hitch angle between a vehicle and a trailer; and
a controller comprising:
an oscillation module that determines a magnitude of oscillation of the hitch angle about a central angle; and
a warning module that generates a warning signal when the magnitude of oscillation exceeds a warning threshold and the central angle is constant; wherein the warning signal is deactivated when the magnitude of oscillation of the hitch angle is reduced below a second threshold that is less than the warning threshold.
11. The trailer sway warning system of claim 10 , further comprising:
a steering angle sensor for sensing a steering angle rate of the vehicle, wherein the warning module generates the warning signal when the steering angle rate is substantially zero.
12. The trailer sway warning system of claim 10 , wherein the magnitude of oscillation of the hitch angle is determined by the amount the hitch angle fluctuates about a zero hitch angle that coincides with a centerline longitudinal axis of the vehicle in alignment with a tongue of the trailer.
13. The trailer sway warning system of claim 10 , wherein the controller generates a braking command for the vehicle to reduce the magnitude of oscillation of the hitch angle when the magnitude exceeds a heightened warning threshold.
14. The trailer sway warning system of claim 10 , wherein the hitch angle sensor comprises a vision-based sensor on the vehicle that monitors a position of the trailer relative to the vehicle for determining the hitch angle.
15. The trailer sway warning system of claim 14 , wherein the vision-based sensor includes an imager that monitors movement of a target fixed to the trailer for determining the hitch angle.
16. A method for providing a trailer sway warning, comprising:
sensing a hitch angle between a vehicle and a trailer;
sensing a dynamic parameter of the vehicle;
generating a warning signal based on the dynamic parameter being constant and the hitch angle oscillating at a magnitude that exceeds a warning threshold; and
deactivating the warning signal when the magnitude of oscillation of the hitch angle is reduced below a second threshold that is less than the warning threshold.
17. The method of claim 16 , wherein the dynamic parameter comprises a yaw rate of the vehicle, and wherein the warning signal is generated when the yaw rate is substantially constant.
18. The method of claim 16 , wherein the dynamic parameter comprises a steering angle rate of the vehicle, and wherein the warning signal is generated when the steering angle rate is substantially zero.