Patent Publication Number: US-2017349181-A1

Title: Lane management system for an automated vehicle

Description:
TECHNICAL FIELD OF INVENTION 
     This disclosure generally relates to a lane management system for operating an automated vehicle, and more particularly relates to a system that determines an alternate-route when the relative-location of an other-vehicle is such that a preferred-lane of a preferred-route is obstructed by the other-vehicle. 
     BACKGROUND OF INVENTION 
     Automated vehicles that select a preferred-route to a destination are known. The timing of when lane changes are made can affect the quality of the passenger experience as the automated vehicle drives itself to the destination. For example, it is preferable to delay traveling in the right-most lane of a roadway that has numerous vehicles entering and exiting the roadway via the right-most lane until as late as possible. However, unexpected traffic situations may prevent the automated vehicle from actually following the preferred-route. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment, a lane management system for operating an automated vehicle is provided. The system includes a navigation-device, a vehicle-detector, and a controller suitable for use on a host-vehicle. The navigation-device is used to determine a preferred-route to a destination of the host-vehicle. The vehicle-detector is used to determine a relative-location of an other-vehicle proximate to the host-vehicle. The controller is in communication with the navigation-device and the vehicle-detector. The controller is configured to determine an alternate-route when the relative-location is such that a preferred-lane of the preferred-route is obstructed whereby the host-vehicle is unable to follow the preferred-route. 
     In another embodiment, a lane management system for operating an automated vehicle is provided. The system includes a navigation-device, a vehicle-detector, and a controller suitable for use on a host-vehicle. The navigation-device is used to determine a preferred-route to a destination of the host-vehicle. The vehicle-detector is used to determine a relative-location of an other-vehicle proximate to the host-vehicle. The controller is in communication with the navigation-device and the vehicle-detector. The controller is configured to determine an initiate-time to perform a lane-change necessary to maneuver the host-vehicle into a preferred-lane of the preferred-route so the host-vehicle can follow the preferred-route, wherein the initiate-time is determined based on the relative-location. 
     Further features and advantages will appear more clearly on a reading of the following detailed description of the preferred embodiment, which is given by way of non-limiting example only and with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The present invention will now be described, by way of example with reference to the accompanying drawings, in which: 
         FIG. 1  is a diagram of a lane management system in accordance with one embodiment; and 
         FIG. 2  is a traffic-scenario encountered by the system of  FIG. 1  in accordance with one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a non-limiting example of a lane management system  10 , hereafter referred to as the system  10 , which is generally configured for operating an automated vehicle, for example a host-vehicle  12 . The examples presented herein are generally directed to instances when the host-vehicle  12  is being operated in an automated-mode  14 , i.e. a fully autonomous mode, where a human operator (not shown) of the host-vehicle  12  does little more than designate a destination  16  to operate the host-vehicle  12 . However, it is contemplated that the teachings presented herein are useful when the host-vehicle  12  is operated in a manual-mode  18  where the degree or level of automation may be little more than providing steering advice to the human operator who is generally in control of the steering, accelerator, and brakes of the host-vehicle  12 , i.e. the system  10  assists the human operator as needed to reach the destination  16  and/or avoid a collision. 
     The system  10  includes a navigation-device  20  suitable for use on the host-vehicle  12  because the navigation-device  20  is designed to operate over the temperature range and other environmental conditions that the host-vehicle  12  may experience. In general, the navigation-device  20  is used by a controller  40  (described in more detail later) of the system  10  to determine a preferred-route  22  to the destination  16  of the host-vehicle  12 . The navigation-device  20  may consist of, but is not limited to, a location-device  24  such as a global-position-system (GPS) receiver used to determine the location of the host-vehicle  12  on a digital-map  42 . Alternatively, or in combination with the GPS receiver, the navigation-device  20  may include an image-device  26 , the function of which may be provided by, but not limited to, a camera  28 , a radar-unit  30 , a lidar-unit  32 , or any combination thereof. While these devices are illustrated as being part of or forming a vehicle-detector  34 , it is contemplated that these devices may also be used by the navigation-device  20  to provide information useful to navigate the host-vehicle  12 . That is, the camera  28 , the radar-unit  30 , and/or the lidar-unit  32  may be used by both the navigation-device  20  and the vehicle-detector  34 . 
     It follows that the vehicle-detector  34  is also suitable for use on the host-vehicle  12 , and is generally used by the controller  40  of the system  10  to determine a relative-location  36  of an other-vehicle  38  proximate to the host-vehicle  12 . By way of example and not limitation, the relative-location  36  of the other-vehicle  38  may be expressed in terms of a bearing-angle (i.e. direction) relative to the forward facing direction of the host-vehicle  12 , and a distance from the host-vehicle  12  to the other-vehicle  38 . Alternatively, the relative-location  36  may be calculated from a difference in global coordinates indicated by the navigation-device  20  and an indication of the global coordinates of the other-vehicle  38  transmitted by the other-vehicle  38  using known vehicle-to-vehicle (V2V) communications. 
     As suggested in  FIG. 1 , the controller  40  is generally in communication with the navigation-device  20  and the vehicle-detector  34  which may be by way of wires, wireless communication, or optical-fiber, as will be recognized by those in the art. The controller  40  may include a processor (not specifically shown) such as a microprocessor or other control circuitry such as analog and/or digital control circuitry including an application specific integrated circuit (ASIC) for processing data as should be evident to those in the art. The controller  40  may include memory (not specifically shown), including non-volatile memory, such as electrically erasable programmable read-only memory (EEPROM) for storing one or more routines, thresholds, and captured data. The one or more routines may be executed by the processor to perform steps for determining, for example, the relative-location  36  based on signals received by the controller  40  for operating the host-vehicle  12  as described herein. 
     In one embodiment of the system  10 , the controller  40  is configured to determine an alternate-route  44  when the relative-location  36  is such that a preferred-lane  46  of the preferred-route  22  is obstructed by the other-vehicle  38  for example. When this happens, the host-vehicle  12  is unable to follow the preferred-route  22 . That is, if the presence of the other-vehicle  38  and/or numerous other-vehicles present in the preferred-lane  46  prevents the host-vehicle  12  from being able to comply with a lane-change-request  50  to complete a lane-change  52  into the preferred-lane  46 , the system  10 , or more specifically the controller  40 , determines that the preferred-route  22  cannot be followed, so the alternate-route  44  is determined or selected to follow to the destination  16 . By way of example and not limitation, the alternate-route  44  may specify a next-turn for the host-vehicle to take if an upcoming-turn that is indicated as the preferred-route is unavoidably missed. 
       FIG. 2  illustrates a non-limiting example of a traffic-scenario  60  where the host-vehicle  12  needs to make the lane-change  52  into the preferred-lane  46  in order to follow the preferred-route  22 . As noted above, in order to provide a pleasant travel experience to a passenger or occupant of the host-vehicle  12 , it may be preferable for the host-vehicle  12  to travel in the left-lane  62  so the speed of the host-vehicle  12  is relatively constant when compared to the possible start/stop traffic caused by the numerous vehicles present in the preferred-lane  46 , which may be making turns onto side-roads  64 A,  64 B. However, in order to prepare for the upcoming turn indicated by the preferred-route  22 , the host-vehicle  12  needs to move into the preferred-lane  46  prior to the upcoming turn. That is, the optimum way to travel the preferred-route  22  is to stay in the left-lane  62  as long as possible, and make the lane-change  52  into the preferred-lane  46  as close as possible to the upcoming turn indicated by the arrow that represents the preferred-route  22 . 
     In view of this preferred strategy when following the preferred-route  22 , an alternative embodiment of the system  10  is envisioned that optimizes the timing for making the lane-change  52 . In this alternative embodiment the controller  40  is configured to determine an initiate-time  48  ( FIG. 1 ) to perform the lane-change  52  necessary to maneuver the host-vehicle  12  into the preferred-lane  46  of the preferred-route  22  so the host-vehicle  12  can follow the preferred-route  22 . By way of example and not limitation, the initiate-time  48  may be determined based on the relative-location  36 . That is, if the relative-location  36  is such that the lane-change  52  is not obstructed or blocked by the other-vehicle  38  or any of the multiple vehicles shown in  FIG. 2  as present in the preferred-lane  46 , the initiate-time  48  can be later, e.g. delayed until a time when the host-vehicle  12  is relatively close to the upcoming turn illustrated by the arrow for the preferred-route  22 . However, if the relative-location  36  is such that the host-vehicle  12  is unable to make the lane-change  52  at any desired moment, the initiate-time  48  would be advantageously selected earlier so there was sufficient time for the host-vehicle  12  to take some action in order to find space to make the lane-change  52 . By way of example and not limitation, if traffic in the preferred-lane  46  is relatively heavy and closely spaced, the host-vehicle  12  may mark the initiate-time  48  by activating a turn-signal  66  to indicate to the other-vehicles in the preferred-lane  46  that the lane-change  52  is desired. 
     Another embodiment is contemplated that combines the above described embodiments so that the controller  40  determines the initiate-time  48  based on the relative-location  36 , and then if it is not possible to make the lane-change  52  before reaching the upcoming turn, the controller  40  abandons the preferred-route  22  and instead follows the alternate-route  44 . 
     Alternatively, or in addition to relying on the relative-location  36  to determine the initiate-time  48 , the controller  40  may be further configured to determine a traffic-density  68  based on how many other-vehicles are present in the preferred-lane  46 , and further determine the initiate-time  48  based on the traffic-density  68 . The traffic-density  68  may be determined using the vehicle-detector  34  and be based on the number of vehicles in the preferred-lane  46  within (e.g. forward and or behind) some predetermined distance of the host-vehicle, within fifty meters (50 m) for example. Alternatively, the average spacing between five other vehicles nearest the host-vehicle  12  and in the preferred-lane  46  may be used as a measure of the traffic-density  68 . If the traffic-density  68  is relatively high, then an earlier value of the initiate-time  48  may be determined. For example, if the traffic-density  68  is relatively high, e.g. there are no spaces between the other vehicles in the preferred-lane  46  large enough for the host-vehicle  12  to occupy following the lane-change  52 , the initiate-time  48  may be set to ninety seconds (90 s) prior to arriving at the upcoming turn indicated by the preferred-route  22 . However, if the traffic-density  68  is relatively low so the host-vehicle  12  can readily make the lane-change  52 , the initiate-time  48  may be set to fifteen seconds (15 s) prior to arriving at the upcoming turn. 
     Alternatively, or in addition to the embodiments describe above, the controller  40  may be further configured to determine a speed  70  (e.g. a mean or median) of other-vehicles present in the preferred-lane  46 , and further determine the initiate-time  48  based on the speed  70 . If the other-vehicles are moving at a relatively low speed, thirty-five kilometers per hour (35 kph) for example, the initiate-time  48  may be delayed as compared to when the other-vehicles are moving at a relatively high speed, one-hundred kilometers per hour (100 kph) for example. 
     Alternatively, or in addition to the embodiments describe above, the controller  40  may be further configured to determine a lane-count  72  and/or lane-width  74  of lanes that must be crossed to reach the preferred-lane  46 , and further determine the initiate-time  48  based on the lane-count  72  and/or lane-width  74 . For the example shown in  FIG. 2 , the lane-count  72  is one so the initiate-time  48  may be relatively short, fifteen seconds (15 s) for example. However, if the roadway has more than the two lanes for a direction of travel shown in  FIG. 2 , additional time may be required to transition across multiple-lanes and/or if the lane-width  74  is unusually large. 
     Alternatively, or in addition to the embodiments describe above, the navigation-device  20  may be used to detect a traffic-signal  76 , and the controller  40  may be further configured to determine a signal-distance  78  from the host-vehicle  12  to the traffic-signal  76 , and further determine the initiate-time  48  based on the signal-distance. That is, the system  10  is configured to decide when to perform lane-change  52  based on the signal-distance  78  to traffic-signal  76  while considering of the traffic-density  68  of the surrounding traffic. By way of further example, if the traffic-signal  76  is relatively close, e.g. within 10 seconds, the system  10  will not try to do a lane change before the traffic-signal or an upcoming intersection that may or may not have a traffic-signal, but will perform the traffic after the traffic-light or intersection. However, if there is a traffic-signal that is not too close, e.g. not less than within 20 seconds, and the traffic-density is relative high (i.e. the traffic is heavy), the system  10  will not try to perform a lane-change before this intersection. Otherwise, if the traffic-density is not too high when the traffic-signal that is not too close, e.g. not less than within 20 seconds, then the system  10  may perform the lane-change. 
     Accordingly, a lane management system (the system  10 ), a controller  40  for the system  10 , and a method of operating the system  10  is provided. The system  10  is generally configured to, as much as possible, keep the host-vehicle in a travel-lane where traffic moves at a steady speed, and delay, as much as possible, making a lane-change into a lane where wide speed variation may be present, where the lane-change is necessitated by the desire to follow a preferred-route to a destination. 
     While this invention has been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow.