Vehicle maneuvering aids

Abstract

A vehicle 1 towing a trailer 4 is fitted with three video cameras 5, 6, 7 fitted to the rear of the vehicle and on each door mirror. A view from any camera can be presented to the driver on a display 11 . A predicted trailer path, calculated in a computing unit 10 , is also presented to the driver on the display 11 as guide lines overlaid on the camera view. The computing unit 10 is also configured to calculate a hitch angle by tracking the position of a trailer-mounted marker in the camera view.

1 . An apparatus displaying the predicted path of a trailer attached to a vehicle, comprising:
 at least one rearward-looking video camera having an output;   a steering angle sensor outputting the steering angle of the vehicle;   a computing unit receiving the video camera output and steering angle and computing a predicted trailer path; and   a display displaying the video camera output and the predicted trailer path.   
   
   
       2 . The apparatus of  claim 1 , wherein the predicted trailer has wheels and the predicted trailer path is represented as overlay tracks beginning at the trailer wheels. 
   
   
       3 . The apparatus of  claim 2 , wherein the predicted trailer path is shown while traveling in a forwards direction. 
   
   
       4 . The apparatus of  claim 1 , wherein the computing unit derives a hitch angle θ t  from the camera output and uses the hitch angle θ t  to determine the predicted trailer path. 
   
   
       5 . The apparatus of  claim 1 , wherein said at least one rearward-looking video camera comprises a camera mounted on each vehicle side mirror. 
   
   
       6 . The apparatus of  claim 1 , wherein the trailer has a geometry and further comprising a store receiving the trailer geometry. 
   
   
       7 . The apparatus of  claim 6 , further comprising the computing unit learning the trailer geometry from observing a maneuver and storing the learned geometry in the store. 
   
   
       8 . An apparatus displaying the predicted path of a trailer having trailer wheels attached to a vehicle, comprising:
 at least one rearward-looking video camera mounted on each vehicle side mirror having an output;   a steering angle sensor outputting the steering angle of the vehicle;   a computing unit receiving the video camera output and steering angle and derives a hitch angle θ t  from the camera output and uses the hitch angle θ t  to determine the predicted trailer path; and   a display displaying the video camera output and the predicted trailer path is represented as overlay tracks beginning at the trailer wheels.   
   
   
       9 . An apparatus tracking objects close to the path of a vehicle, comprising:
 at least one vehicle-mounted video camera with pan capability, the camera having an output;   a vehicle-mounted proximity sensor sensing the location of the object;   a steering angle sensor outputting the steering angle of the vehicle;   a speed sensor outputting the speed of the vehicle;   a computing unit receiving the speed and steering angle and calculating a relative position of the object and panning the camera to follow the object; and   a display displaying the video camera output.   
   
   
       10 . The apparatus of  claim 9 , wherein the camera further comprises zoom capability and the computing unit zooms the camera when following the object. 
   
   
       11 . An apparatus informing a vehicle when a trailer is hitched to the vehicle, comprising
 a rearward-looking camera having an output; and   an image processor receiving the output and comparing the output with parameters stored in a store to determine the presence of the trailer.   
   
   
       12 . The apparatus of  claim 11 , further comprising comparing the output with the stored parameters to determine the type of trailer. 
   
   
       13 . The apparatus of  claim 12 , further comprising using the trailer type in a vehicle control system. 
   
   
       14 . The apparatus of  claim 13 , wherein the vehicle control system is a stability control system and the type of trailer is trailer weight. 
   
   
       15 . The apparatus of  claim 12 , wherein the trailer type is confirmed by monitoring the dynamic behavior of the vehicle and trailer. 
   
   
       16 . An apparatus for assisting in hitching a trailer having a tow hitch to a vehicle, comprising:
 at least one vehicle-mounted video camera having an output;   an image processor receiving the camera output and identifying the tow hitch and displaying the output as an image;   a display displaying the image, the image processor zooming the image to display a close-up of the tow hitch and adjusting the image zoom as the vehicle moves relative to the trailer to maintain the tow hitch in the image.   
   
   
       17 . The apparatus of  claim 16 , further comprising a steering angle sensor outputting the steering angle of the vehicle;
 a computing unit receiving the video camera output and steering angle and computing a projected vehicle trajectory; and   displaying the projected vehicle trajectory overlaid as a guide line on the zoomed image.   
   
   
       18 . The apparatus of  claim 17 , wherein the vehicle has a tow ball not visible to the camera and further comprising displaying a virtual location of the tow ball on the display. 
   
   
       19 . A method of predicting the path of a trailer attached to a vehicle comprising the steps of:
 obtaining a view from a first rearward-looking, vehicle-mounted video camera on a screen visible to the driver;   determining the predicted path of the trailer;   displaying the predicted trailer path as an overlaid track on the rearward-looking view.   
   
   
       20 . The method of  claim 19 , further comprising the step of determining a hitch length, H, between an axle of the trailer and a point of attachment of the trailer to the vehicle and using H to calculate the predicted trailer path. 
   
   
       21 . The method of  claim 19 , further comprising the step of determining a hitch angle, θ t , between the vehicle and trailer and using θ t  to calculate the predicted trailer path. 
   
   
       22 . The method of  claim 19 , further comprising the step of calculating a turning radius R where R=H/θ t , where the trailer is predicted to follow the circumference of a circle of radius R and using R to calculate the predicted trailer path. 
   
   
       23 . The method of  claim 19 , further comprising the steps of:
 determining a hitch length, H, between an axle of the trailer and a point of attachment of the trailer to the vehicle;   determining a hitch angle, θ t , between the vehicle and trailer;   calculating a turning radius R where R=H/θ t , where the trailer is predicted to follow the circumference of a circle of radius R; and   using H, θ t , and R to calculate the predicted trailer path.   
   
   
       24 . The method of  claim 21 , wherein the hitch length H is determined by driving the vehicle-trailer combination in a circular path, while measuring a vehicle steering angle θ s , calculating the radius R of the circular path from θ s  and knowledge of the dimensions of the vehicle, measuring a hitch angle θ t  and calculating a hitch length H from the relationship H=Rθ t . 
   
   
       25 . The method of  claim 19 , further comprising the steps of:
 obtaining a view from a second rearward-looking, vehicle-mounted video camera,   determining which of the first and second camera views shows the trailer; and   displaying the determined view on the screen.   
   
   
       26 . The method of  claim 21 , wherein the hitch angle θ t  is determined by the steps of:
 tracking a marker associated with the trailer across a field of view of the rearward-looking video camera; and   converting a lateral displacement of the marker in the field of view to an angular displacement.   
   
   
       27 . A method of predicting the path of a trailer attached to a vehicle comprising the steps of:
 measuring the vehicle steering angle;   obtaining first and second views from at least two rearward-looking, vehicle-mounted video cameras;   determining a trailer view from the first and second camera views;   displaying the trailer view on a screen visible to the driver;   determining a hitch angle, θ t , between the vehicle and trailer and using the trailer view;   calculating a predicted path of the trailer from the hitch angle and steering angle; and   displaying the predicted trailer path as an overlaid track on the trailer view.