Vehicle-trailer backing up jackknife detection and warning system

DETAILED DESCRIPTION The jackknifing warning system of the present invention utilizes vehicle steering wheel angle sensor signal, vehicle travel speed and hitch articulation angle to evaluate system stability.
Based on a hitch angle equilibrium position, hitch angle rate and some predetermined criteria, the system utilizes an algorithm to determine if the motion of vehicle-trailer combination is stable or not with driver in the loop.
When instability is detected, a critical hitch angle will be calculated as a function of hitch angle rate, a predetermined maximum critical hitch angle and a predetermined tolerant time period to determine if and how the vehicle-trailer is approaching jackknifing.
If the vehicle-trailer surpasses the critical angle, a proper warning signal is issued with varying intensity as the severity varies.
The algorithm also provides steering direction assistance in order for the driver to steer to avoid jackknifing.
This invention can apply to vehicle with either two-wheel steer or four-wheel steer with a trailer.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter.
It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.