The present invention relates generally to trailer locating devices and, more specifically, it relates to a trailer hitch alignment system for assisting a user to align a hitch of a vehicle with a trailer hitch.
Users of trailers often have great difficulty in aligning their vehicle's hitch with the trailer hitch of a conventional trailer. A conventional trailer has a plurality of wheels rotatably supporting a frame and a trailer hitch for removably coupling with a vehicle that will be towing the conventional trailer. The user must align the hitch of the vehicle with the raised trailer hitch. This is extremely difficult since the hitch is usually out of viewing because of its location upon the vehicle's bumper. Generally, two persons are required to effectively and efficiently align the vehicle hitch with the trailer hitch. However, when the user is trying to align the hitches alone, the user must then slowly back up to the trailer hitch so as to prevent damage to the vehicle and trailer, stop the vehicle, exit the vehicle, view the position of the hitch relative to the trailer hitch to prevent damage to the trailer hitch and/or the vehicle, and then reenter the vehicle to repeat the process. This process is then generally repeated numerous times until the vehicle hitch and trailer hitch align. Hence, there is a need for a trailer hitch alignment system that allows a user to conveniently and precisely align a vehicle hitch with a trailer hitch without the user having to repeatedly exit the vehicle.
The repeated exiting and entering the vehicle is undesirable to users. In addition, the constant exiting and entering of the vehicle is time consuming and potentially dangerous. Mother issue is the inevitable likelihood of vehicle or trailer damage during attempts for trailer hitch alignment.
Devices presently in the art for trailer hitch alignment include systems utilizing cameras that are attached to the rear of the vehicle and display in the passenger compartment a view of the vehicle trailer hitch. Other devices include systems with mirrors mounted to provide a view of the vehicle's hitch. These systems are often expensive, inconvenient, and cumbersome to use.
These and other objects, advantages and features of this invention will become apparent upon review of the following specification in conjunction with the drawings.
a-4c are perspective views of a vehicle hitch with a visible target applied to the vehicle hitch;
a-5d are perspective views of an alternative embodiment of a visible target;
a-6c are perspective views of another alternative embodiment of a visible target;
Referring now specifically to the drawings, and the illustrative embodiments depicted therein, a trailer alignment system 10 is illustrated for use with aligning a trailer hitch 14 of a trailer 11 with a vehicle hitch 16 of a vehicle 12 (
Trailer alignment system 10 may additionally include a driver interface module 20, which is positioned in the driver's cab in order to provide visual and/or audible signals to the driver. Alternatively, trailer alignment system 10 may provide steering commands directly to the vehicle steering system in order to automate the trailer alignment process. Trailer alignment system 10 may additionally include a visual target 22 which is configured to be applied to the hitch 16, 18 that is opposite to the hitch 16, 18 to which the sensor 18 is applied (
In the illustrative embodiment, sensor 18 is a camera system and, in particular, a stereoscopic-imaging system. As is known in the art, a stereoscopic-imaging system has two image sensors that are adapted to capturing at least two different images of a surface of an object at a distance. If stereoscopic-imaging system 18 is positioned at the trailer hitch, it captures an image of a surface at the vehicle hitch. If imaging system 18 is positioned at the vehicle hitch, it captures an image of a surface at the trailer hitch. In the illustrative embodiment, stereoscopic-imaging system 18 utilizes a commercially available digital stereo head of the type marketed by Videre Design Company. However, other stereoscopic-imaging techniques may be used. Stereoscopic-imaging system 18 additionally includes a control 26 having a computational unit, such as a processor 28 which processes digital images produced by two image sensors 30a, 30b that are at a fixed relationship to each other that allows the image sensors to capture stereoscopic images of the opposite hitch (
Computational unit 28 produces steering data at an output 40 that may be used to provide visual and/or audio information to a driver, such as using a video display 42 or speakers (not shown) that are part of driver interface module 20. Where sensor 18 is positioned at the trailer hitch, a communication channel, such as a wireless communication channel including an RF transceiver 44 at sensor unit 18 and RF transceiver 46 at the driver interface module, may be utilized for communication. Other wireless communication, such as infrared, Bluetooth, or the like, may also be used. Alternatively, communication signals may be modulated over the vehicle-to-trailer wiring bundle. Where sensor 18 is at the vehicle hitch, it is possible to connect driver interface module 20 with sensor 18 by wireless communication, hardwired communication, fiber optics, or the like.
Visual target 22 provides an assist for capturing of an image of the hitch opposite the hitch bearing sensor 18 in order to assist in determining the position of the hitch opposite sensor 18. As best seen by reference to
In an alternative embodiment illustrated in
In another alternative embodiment, a visual target 222 includes one or more light sources 52 in order to illuminate surface 244. By illuminating surface 244, the visual contrast provided by visual texture features 246 becomes greater. This may be particularly useful, by way of example, where visual target 222 is adapted to be positioned on ball hitch 24. As a visual imaging system, sensor 18 could, otherwise, be blinded by, for example, the vehicle's backup lights, which would be illuminated while the vehicle is backing up to position the trailer hitch and vehicle hitch together. By enhancing visual contrast, light source 52 allows the sensor to determine the position of visual target 222 even in the presence of the vehicle's illuminated backup lights, as well as other sources of visible noise, such as the lines of the vehicle, and the like. Light source 52 may be useful during daytime and nighttime conditions. Light source 52 may be a light-emitting diode (LED) source with a self-contained battery 53. Alternatively, the light source may be powered from the vehicle's battery and may be configured to be energized when the vehicle's backup lights are energized. Visual target 222 may include a wire bundle (not shown) having a connector which connects with a conventional trailer connector on vehicle 12. The connector on visual target 222 may be configured to plug into the conventional connector on the vehicle and provide for connection with the cable extending from the trailer 11. This would allow the light source 52 to receive power from the vehicle without requiring separate wiring of the visual target to the vehicle.
Other variations will be apparent to the skilled artisan. For example, rather than light source 52 being an internal light source, it could be an external light source directed onto visual texture features 246. Alternatively, light source 52 could be a reflector to reflect the backup lights of the vehicle, or other light source, toward the visual texture features of surface 44, 144, 244, or the like. Also, although visual target 22, 122, 222 is illustrated as a cylindrical shaped surface, it could be a flat surface or other three-dimensional shape. Also, it should be understood that visual texture features 46, 146, 246 may be applied directly to ball hitch 24, to a surface of vehicle 12, or to a surface of trailer 11.
Operation of sensor 18 may be understood by reference to
The disparity value can then be used to find which pixels correspond in the two images. One of the two images is typically considered to be the reference image. Pixels in the reference image have higher x coordinates than their corresponding pixels in their other image. The x coordinates correspond to lateral left-to-right locations. The y coordinates, which correspond to vertical dimensions, are the same for both images. The x coordinates are related by xr and xL minus 16d where disparities are specified in units of 1/16 pixels. Disparity calculations and determination of which pixels correspond in the two images is known in the art and is disclosed in detail in a publication entitled “SRI Small Vision System,” User's Manual, Software Version 4.2, published in February 2006 by SRI International, the disclosure of which is hereby incorporated herein by reference.
Computational unit 28 may be programmed with algorithms to carry out the object recognition illustrated in
Video produced by video conversion algorithm 42 may be of the type illustrated in
A process 70 carried out by digital signal processor 28 to produce steering data begins at 72 with system initialization (
Once the coordinates of the position of visual target 22 have been obtained at 86, a projection of the anticipated path of vehicle trailer hitch is made at 88 and displayed with video display 42 at 90. Current path projection algorithms are known in the art. An example includes the backup system utilized with the commercially availably Lexus LS 460 vehicle marketed by Toyota. The processor also determines an ideal path at 90, which would be an optimal path to direct the vehicle hitch toward the trailer hitch, and provide steering data at 92. The steering data may be advised to the driver, such as audible commands (“turn left,” “turn right”) or by the display of a path with video display 42. Examples of ideal path calculations are known in the art and are within the knowledge of the skilled artisan.
The use of stereoscopic imaging allows the trailer alignment system to provide data to the driver and/or the vehicle to guide the vehicle hitch toward the trailer hitch at a greater distance than is known with prior systems and to do so in a more accurate manner. Also, it may do so in an intuitive manner that assists the driver in moving the vehicle, which is typically in reverse gear, to cause the vehicle hitch to become aligned with the trailer hitch. This is accomplished in a manner that may be incorporated into the vehicle for OEM applications or may be marketed as an aftermarket application. The use of a visual target having visual texture features facilitates object recognition to enhance the ability of the system to calculate the location of the target position opposite the sensor or detection unit.
The use of a visual target, which may be in the form of a cap to fit over the ball hitch of the vehicle hitch, provides a device that may be applied to the vehicle when in use and removed for connection of the hitches thereby allowing the visual target to be stored away from the elements when not in use. Also, the ability in certain embodiments to internally illuminate the visual target facilitates the ability to distinguish the visual target in the presence of, for example, vehicle backup lights which will be illuminated during the trailer alignment process, as well as other sources of visible noise, such as the lines of the vehicle, and the like.
The trailer alignment system disclosed herein may include a display that is user friendly and relates the positioning between the vehicle hitch and the trailer hitch coupler as the vehicle moves towards the trailer. The driver interface module may be mounted inside the vehicle or held by the driver. An RF transceiver may be incorporated into the display and the sensor unit to transmit data wirelessly from the sensor unit and display the data on the video display. The display may show the positioning in a “birds-eye” view with each trailer hitch being depicted as either a dot or a circle. However, other embodiments may include other shapes. On the display, the trailer hitches will be oriented in a vertical relationship with the trailer coupler icon located at the bottom of the display in a stationary position and the vehicle hitch icon located at the top of the display. The top indicia will move in a vertical direction downwardly as the vehicle moves closer to the trailer. This alignment will be displayed by the incorrect path that the vehicle hitch indicia, or icon, takes on the display as it nears the trailer hitch icon. Once the dot is positioned inside the circle, the representation demonstrates that the ball hitch is located under the trailer hitch coupler such that the coupler can be lowered onto the ball hitch once a visual target is removed from the ball hitch. Upon alignment, an audible or visual acknowledgement of alignment may be generated by driver interface module 20.
Changes and modifications in the specifically described embodiments can be carried out without departing from the principles of the invention which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents.
This application claims priority from U.S. application Ser. No. 60/947,808, filed on Jul. 3, 2007, the disclosure of which is hereby incorporated herein by reference in its entirety.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US08/69038 | 7/2/2008 | WO | 00 | 12/28/2009 |
Number | Date | Country | |
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60947808 | Jul 2007 | US |