Vehicle turning assist system and method

[0001] The present invention generally relates to vehicle imaging systems and, more particularly, to a video information system and method for assisting the driver of the vehicle when maneuvering turns, particularly for a trailering vehicle.

[0002] Automotive vehicles are commonly equipped with exterior mounted side view mirrors located on both lateral sides of the vehicle. The side view mirrors allow the driver to generally view the exterior side regions of the vehicle. Typical mirror assemblies employ a linear or non-linear convex reflective lens providing a limited field of view (e.g., fifteen to twenty degrees (15°-20°)) to allow the driver to view the nearby side region. The side mounted mirrors assist the driver in detecting objects in the adjacent side lanes, particularly prior to performing a lane change maneuver.

[0003] The side view mirror assemblies alone are generally sufficient to monitor the adjacent lane for many automotive passenger vehicles. However, for vehicles hauling towed structures, such as passenger vehicles with towed trailers or commercial vehicles (e.g., semi-trucks) with towed trailers, the conventional side view mirror assembly alone may be insufficient to adequately monitor the entire side regions as the vehicle turns. When a trailering vehicle turns severely towards the left or right side, the vehicle, particularly the trailered body, is pulled in a travel path that projects into the turn.

[0004] With the conventional vehicle mirror assembly, the resulting field of view offered by the mirror does not allow the driver of the vehicle to easily view the entire path of the trailered body, thereby resulting in a trailer-side blind zone. In lieu of a conventional linear mirror, a non-linear convex mirror surface could be employed. However, the driver may find it difficult to optically interpret the non-linear mirror image that is presented.

[0005] It is therefore desirable to provide for a system and method that assists the driver of the vehicle when turning the vehicle. In particular, it is desirable to provide for such a system and method that enables the driver of a trailer towing vehicle to more easily manipulate sharp turning maneuvers of the vehicle.

[0006] In accordance with one aspect of the present invention, a turning maneuver assist system is provided for assisting the driver of a vehicle with a visual image while turning the vehicle. The system includes first and second cameras positioned to generate video images on respective first and second sides of a vehicle. The system also includes a display adapted to be located onboard the vehicle for displaying images generated by one of the first and second video cameras when one of the first and second video cameras is activated. The system further includes a controller for controlling activation of the first and second cameras and the presentation of images on the display. The controller activates one of the first and second cameras and controls the display to output images captured by the activated camera when the vehicle is determined to be turning.

[0007] According to another aspect of the present invention, a method of assisting a driver of a vehicle when the vehicle is turning is provided. The method includes the steps of determining when the vehicle is turning towards a first side. The method also includes the step of activating a first camera to capture video images on the first side of the vehicle when the vehicle is determined to be turning towards the first side. The method further includes the step of displaying the video images captured by the first camera on a display onboard the vehicle. The method further includes the step of deactivating the first camera when the vehicle is not turning sufficiently in a direction towards the first side.

[0008] Accordingly, the system and method of the present invention provide a video image on the display showing a view of the side region of the vehicle toward which the vehicle is turning. The system and method are particularly well adapted for use on a trailering vehicle to enable the driver to view a video image of a side region of the vehicle and the trailered body when the vehicle is performing a tight turning maneuver.

[0009] These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.

[0019] Referring to FIGS. 1 and 2, a trailer towing vehicle 10 is generally illustrated traveling in a substantially straight path in FIG. 1, and traversing a tight turn towards the right side in FIG. 2. The vehicle 10 may include a commercial vehicle, such as a semi-truck, towing a trailer body 12 according to one embodiment. According to another embodiment, vehicle 10 may include a passenger vehicle, such as a recreational vehicle, adapted to tow a trailer body 12. The vehicle 10 shown generally includes a hitch 14, such as a fifth wheel hitch, for connecting to the trailer body 12.

[0020] The vehicle 10 is shown having first and second externally mounted side view mirrors 16A and 16B. The first side view mirror 16A is mounted on the left side, also referred to as the driver side, of the vehicle 10 and allows the driver of the vehicle 10 to view a limited side region of the vehicle 10 within a limited field of view 18A. The second side view mirror 16B is mounted on the right side, also referred to as the passenger side, of the vehicle 10 and allows the driver to view the right side of the vehicle 10 within a limited field of view 18B. Mirrors 16A and 16B provide a viewing angle θ_MIRROR that defines the respective mirror fields of view 18A and 18B.

[0021] The vehicle 10 employs a turning maneuver assist system 20 for assisting the driver of the vehicle 10 in maneuvering turns according to the present invention. The turning maneuver assist system 20 includes a first video camera 22A located on the first side of the vehicle 10 and a second video camera 22B located on the second side of the vehicle 10. The first and second video cameras 22A and 22B are mounted on the vehicle 10 at unobtrusive locations on the respective lateral sides of the vehicle 10 that enable each of the cameras 22A and 22B to capture an enhanced field of view video image of the corresponding exterior side region of the vehicle 10.

[0022] The first video camera 22A provides a video image of a field of view that is wider than the field of view 18A of the reflective image seen on mirror 16A. Similarly, the second video camera 22B provides an enlarged field of view 24 wider than the field of view 18B provided by the second mirror 16B. The first and second video cameras 22A and 22B each provide an imaging angle θ_CAMERA that defines the corresponding camera field of view 24.

[0023] The first and second video cameras 22A and 22B may be mounted on the corresponding left and right exterior sides of the vehicle 10 looking rearward, so that each of cameras 22A and 22B is capable of providing a field of view 24 that is substantially parallel to the ground along the side region of the vehicle 10 and its trailer 12. Each of the first and second cameras 22A and 22B may possess a sufficient azimuth and elevation field of view 24 to allow a complete unobtrusive view along the entire side of the trailer 12 at the maximum turning angle between the vehicle 10 and its trailer 12.

[0024] In order to minimize the required camera field of view 24, the first and second video cameras 22A and 22B may be mounted towards the front of the vehicle 10, such as in a space behind the left and right corners of the front bumper of the vehicle 10, looking rearward. As a result, each of the first and second video cameras 22A and 22B is capable of providing a sufficient field of view 24 to observe objects, such as object 26 (e.g., curb, tree, utility pole, etc.), in the near side vicinity of the trailer 12 that may be in the travel path of the trailer 12 when the vehicle 10 traverses a turning maneuver at turning angle θ_TURN, such as is seen in FIG. 2.

[0025] The turning maneuver assist system 20 is shown in FIG. 3 further having a controller 30, an onboard display 50, and left and right infrared (IR) illuminators 28A and 28B. The IR illuminators 28A and 28B may be activated at night to illuminate the field of view 24 of the corresponding left and right cameras 22A and 22B. The onboard display 50 receives the video images captured by the left and right video cameras 22A and 22B and displays the video images to the driver of the vehicle 10 when the vehicle 10 is turning.

[0026] The controller 30 receives a plurality of signal inputs, including a steering wheel angle θ_STEERING signal 40, a vehicle speed V_YAW signal 42, a yaw rate ω_YAW sensor signal 44, a left turn signal 46, a right turn signal 48 and the transmission position signal PRNDL 49. Controller 30 has a microprocessor 32 and memory 34. The microprocessor 32 may include a conventional microprocessor having the capability for processing algorithms and data. Memory 34 may include read-only memory (ROM), random access memory (RAM), flash memory and other commercially available volatile and non-volatile memory devices. Stored within memory 34 and executed by microprocessor 32 is a turning assist routine 100. It should be appreciated that the controller 30 may include an electronic controller dedicated to the turning maneuver assist system 20, or may include a shared controller, such as a body controller of the host vehicle 10, according to other embodiments.

[0027] The controller 30 receives and processes any of a number of the inputs 40-49, and estimates the turning angle θ_TURN, according to one embodiment. This may be achieved by employing a turning angle estimation routine. According to one embodiment, the turn angle θ_TURN is estimated as a function of vehicle speed V_YAW, yaw rate ω_YAW and steering angle θ_STEERING. It should be appreciated that the turning angle θ_TURN may be determined based on any of a number of input signals.

[0028] Controller 30 processes the determined turning angle θ_TURN of the vehicle 10 and controls activation of the left and right cameras 22A and 22B and display 50, in order to assist the driver of the vehicle 10 by providing displayed video images of the side of the vehicle 10 towards which vehicle 10 is turning. Additionally, controller 30 may activate the left and right infrared illuminators 28A and 28B to provide sufficient illumination for capturing video images during nighttime operation. In addition, or alternatively, the illuminators 28A and 28B may include visible light illuminators.

[0029] The onboard vehicle display 50 is further illustrated in FIGS. 4-7. The display 50 shown is a drop-down display that moves between an upward stowed position in an overhead storage compartment 56 as seen in FIGS. 6 and 7 and a use position in view forward of the driver above the steering wheel 54 as seen in FIGS. 4 and 5. The display 50 moves upward and downward through an opening 70 in the lower region of the overhead storage compartment 56. The display 50 is a forward view display located on the driver's centerline looking forward in front of windshield 52, and is easily viewable from the driver seat and the rear cab of the vehicle 10.

[0030] The drop-down display 50 may include a liquid crystal display (LCD), or other relatively thin panel monitor display. The display 50 is rigidly connected to a generally T-shaped transport rack 66 via fasteners, such as bolts, for example. Transport rack 66 has teeth 68 which engage teeth 64 of gear 62. Gear 62 is driven by a motor 60. The motor 60 is an electric motor that may be controlled by the controller 30 to drive the drop-down display 50 downward to the fully downward use position and to raise the display 50 to its retracted position fully stowed in compartment 56. The motor 60 and gear 62 are mounted in the overhead compartment 56.

[0031] It should be appreciated that the display 50 may include alternative automatic and manual actuated display devices. According to another embodiment, the drop-down display 50 may be manually actuated by the driver of the vehicle 10 between the upward stowed position and downward use position. According to a further embodiment, the display 50 may include a flip-type display in which the display pivots on one end between a downward extending use position and an upper stowed position. For example, a flip-type display could be integrated into the overhead visor of the vehicle 10 and pivot about one edge of the visor.

[0032] Referring to FIG. 8, the turning assist routine 100 is illustrated according to one embodiment. Routine 100 begins at step 102 when the vehicle ignition is turned on and, hence, the vehicle 10 is operating. Thereafter, variables and constants are initialized in step 104. The initialization step includes setting angle θ_HYSTERESIS equal to constant C_HYSTERESIS and setting angle θ_MIRROR equal to constant C_MIRRORS. Angle θ_HYSTERESIS defines the amount of angular hysteresis that is factored in when determining if the vehicle is turning or no longer turning. Angle θ_MIRROR represents the angular field of view of the side view mirrors. Additionally, the display and camera logic variables L_DISPLAY and L_CAMERA, respectively, are set to the logic off setting.

[0033] Following the initialization, turning assist routine 100 proceeds to step 106 to collect vehicle data. The vehicle data collected includes the vehicle speed (V_YAW), the steering wheel angle (θ_STEERING), and the sensed yaw rate (ω_YAW). Additionally, the collected vehicle data includes the left and right turn signals and the transmission position indicator signal PRNDL. The collected vehicle data signals are then filtered and conditioned according to known signal processing techniques in step 108.

[0034] Proceeding to decision step 110, routine 100 determines if the vehicle transmission is engaged in either park (P) or reverse (R) and, if so, deactivates the display and cameras by setting the display and camera logic variables L_DISPLAY and L_CAMERA to the off setting. In effect, the turning assist system 20 is disabled whenever the vehicle 10 is in park or reverse, according to one embodiment. It should be appreciated that according to another embodiment, the turning assist system 20 may be enabled when the vehicle 10 is in reverse to provide turning assist viewing when the vehicle 10 is backing up.

[0035] The turning assist routine 100 determines several system variables in step 112. These system variables include the turn angle θ_TURN, the turn angle rate {dot over (θ)}_TURN, and the mirror correction angle θ_CORRECTION. The turn angle θ_TURN may be estimated as a function of the yaw rate ω_YAW, vehicle speed V_YAW, and the steering angle θ_STEERING, according to one embodiment. This may be achieved by using the steering angle θ_STEERING when vehicle speed V_YAW is less than a speed threshold e.g., ten miles per hour. The angle θ_TURN may be determined based on various one or more parameters including any of the steering wheel angle θ_STEERING, vehicle speed V_YAW, yaw rate ω_YAW, left and right turn signals and other data.

[0036] The turn angle rate {dot over (θ)}_TURN may be determined by computing the derivative of the turn angle θ_TURN. Turn angle rate {dot over (θ)}_TURN is the rate of change of the turn angle as a function of time. The mirror correction angle θ_CORRECTION defines the field of view not seen in the viewing angle of the mirror. The mirror correction angle θ_CORRECTION may be determined as a function of the turn angle θ_TURN and the turn angle rate {dot over (θ)}_TURN. This determination is predetermined based on the vehicle geometry including any towed structures.

[0037] Turn assist routine 100 determines if the display logic L_DISPLAY setting is set on in step 114. If the display logic L_DISPLAY is set on, routine 100 proceeds to step 116 which determines if the absolute value of the turn angle θ_TURN is less than the mirror angle θ_MIRROR minus both the correction angle θ_CORRECTION and angle θ_HYSTERESIS and, if so, returns to step 106. If the absolute value of the turn angle θ_TURN is greater than or equal to the mirror angle θ_MIRROR minus both the correction angle θ_CORRECTION and hysteresis angle θ_HYSTERESIS, then routine 100 proceeds to step 118 to deactivate the display and cameras by setting the camera and display logic L_CAMERA and L_DISPLAY to off before returning to step 106. Accordingly, routine 100 deactivates the display and the cameras whenever the turn angle θ_TURN is less than a turn threshold, wherein the turn threshold is determined as a function of the mirror angle θ_MIRROR, correction angle θ_CORRECTION, and hysteresis angle θ_HYSTERESIS, according to the embodiment shown.

[0038] Returning back to step 114, if the display logic L_DISPLAY is set to off, turn assist routine 100 proceeds to decision step 120 to determine if the absolute value of the turn angle θ_TURN is greater than the mirror angle θ_MIRROR minus the correction angle θ_CORRECTION, and, if not, deactivates the display and cameras by setting logic L_DISPLAY and L_CAMERA off in step 118, before returning to step 106. If the absolute value of the turn angle θ_TURN is less than or equal to the difference in the mirror angle θ_MIRROR and correction angle θ_CORRECTION, routine 100 activates the display in step 122 by setting the display logic L_DISPLAY on, and then proceeds to activate the appropriate side camera. This includes decision step 124 which determines if the turn angle θ_TURN is to the right or left. If the vehicle is determined to be turning to the right in decision step 124, then the right side camera is activated in step 126. Otherwise, if the vehicle is determined to be turning left, then the left side camera is activated in step 128. Thereafter, routine 100 is repeated by returning to step 106, until the vehicle ignition is turned off.

[0039] Accordingly, the turn assist routine 100 estimates the turn angle θ_TURN, and determines when the vehicle 10 is turning sufficiently beyond a threshold angle sufficient to require activation of a side view camera and the display to aid while the vehicle is performing a tight turning maneuver. The captured video images from the activated camera are displayed on the drop-down display 50 to enable the driver of the vehicle 10 to monitor the side view blind zone when performing the turning maneuver.

[0040] The vehicle turning maneuver assist system 20 and turn assist routine 100 advantageously provides for a low cost integrated turn assist system for assisting the driver of the vehicle 10 in maneuvering the vehicle 10 during a tight turning maneuver. It should be appreciated that various components of the system 20 including the video cameras 22A and 22B, display 50, and IR illuminators 28A and 28B may be integrated within the vehicle 10 to provide other functionality. For example, the side view cameras 22A and 22B, IR illuminators 28A and 28B, and display 50 could be employed to provide vehicle security monitoring as disclosed in U.S. application Ser. No. 11/123,429, entitled “VEHICLE SECURITY MONITOR SYSTEM AND METHOD,” filed on the same date, the entire disclosure of which is hereby incorporated herein by reference. The cameras 22A and 22B, IR illuminators 28A and 28B, and display 50 could also serve to monitor the adjacent lanes for assistance in changing lanes. It should further be appreciated that the drop-down display 50 may be employed to display video images and information using any of a number of applications including navigation, entertainment and other information.

[0041] It will be understood by those who practice the invention and those skilled in the art, that various modifications and improvements may be made to the invention without departing from the spirit of the disclosed concept. The scope of protection afforded is to be determined by the claims and by the breadth of interpretation allowed by law.