This disclosure generally relates to a lane-keeping system for an automated vehicle, and more particularly relates to a system that initiates a lane-change to a first-lane from a second-lane after a first-time-interval after a lane-change to the second-lane that was initiated by an operator when the first-lane is available for unimpeded travel by the host-vehicle for greater than a second-time-interval.
It is known for an automated vehicle to autonomously change lanes to, for example, pass another vehicle. However, in some situations a passenger/operator of the automated-vehicle may want to change lanes for reasons unknown to the automated vehicle.
Described herein is a lane-keeping system that provides for relatively long timers (e.g. 25 s) that are used to prevent autonomous lane-changes. For example, an operator/passenger may abort an autonomous lane-change by, for example, moving the hand-wheel (i.e. steering-wheel) or by operating a turn signal control lever in direction opposite of the direction of the autonomous lane-change. As a result, a suppression timer is started that temporarily suppresses lane-changes in the direction of the aborted lane-change. In another scenario, when the operator manually changes lanes or otherwise requests a lane-change, a suppression timer is started that temporarily prevents a lane-change back to the previous lane. It is also contemplated that when timers from either of these scenarios are active and a highway exit or highway split is within a given distance (e.g., 1 km) of a host-vehicle position (as identified using a digital map), in the direction of the requested or manually-executed lane-change, the timer is extended until the exit or highway split is passed.
In accordance with one embodiment, a lane-keeping system for an automated vehicle is provided. The system includes a lane-detector, an object-detector, and a controller. The lane-detector indicates which lane of a roadway is occupied by a host-vehicle. The object-detector detects objects proximate to the host-vehicle. The controller is in communication with the lane-detector and the object-detector. The controller is configured to operate the host-vehicle to follow a first-lane using the lane-detector when no object is detected by the object-detector in the first-lane that warrants a lane-change, and no lane-change from the first-lane is initiated by an operator of the host-vehicle. The controller is also configured to allow a lane-change to a second-lane when initiated by the operator. The controller is also configured to initiate a lane-change to the first-lane from the second-lane after a first-time-interval after the lane-change to the second-lane that was initiated by the operator when the first-lane is available for unimpeded travel by the host-vehicle for greater than a second-time-interval.
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.
The present invention will now be described, by way of example with reference to the accompanying drawings, in which:
The system 10 includes a lane-detector 24 that indicates which lane of a roadway 26 (
The system 10 includes a controller 30 in communication with the lane-detector 24 and the object-detector 28. The communication may be by way of wires, optical-cable, or wireless communications. The controller 30 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 30 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 to determine the relative location of instances of the objects 20 based on signals received by the controller 30 from the lane-detector 24 and/or the object-detector 28 and to operate the host-vehicle via the vehicle-controls 32 as described herein.
In the examples presented herein it is generally presumed that the host-vehicle 12 will be operating in the automated-mode 14 where the controller 30 is generally in control of the steering, accelerator, and brakes of the host-vehicle 12. In certain circumstances the operator 18 of the host-vehicle may wish to initiate a lane-change or prevent the controller 30 from initiating/completing a lane-change. Various example scenarios of how the operator alters the operation of the host-vehicle 12 that is not consistent with the baseline programming of the controller 30 to operate the host-vehicle 12 in traffic will now be described.
As will be explained in more detail below, there are generally two circumstances that warrant a lane-change. The first being that there is something in the present lane of travel (e.g. the first-lane 40 in
Referring now to
While the center-lane is indicated as the second-lane 42, the lane-change could include moving the host-vehicle into the far-left-lane of the roadway 26 if there were reason to do so. For example, there may be other-vehicles to pass in both the right-lane and the center-lane. It is also contemplated that if the center-lane were the preferred lane and the host-vehicle was traveling in the center-lane of the roadway 26, the lane-change could be to the right-lane from the center-lane of the roadway 26 if there were a reason to do so such as an accident blocking the left-lane and the center-lane of the roadway 26.
Referring now to
It is recognized that the configuration or programming of the controller 30 may differ from what the operator 18 personally prefers. Also, the operator 18 may have personal/historical knowledge about traffic flow patterns on a frequently traveled road that may suggest when a preemptive or anticipatory lane-change may be advisable. As such, the controller 30 may be programmed or configured to maintain position in a lane that was selected by the operator 18 in certain situations. For example, the controller 30 may be further configured to remain in the second-lane 42 after the first-time-interval 44 expires when a roadway-divergence 48, e.g. an exit ramp or a fork in the roadway 26, is located within a predefined-distance 50 of the host-vehicle 12 and until the roadway-divergence 48 is passed by the host-vehicle 12. The presence of the roadway-divergence 48 may be detected by object-detector 28 or indicated on digital-map 52 accessible by the controller 30.
Another recognized situation where the configuration or programming of the controller 30 may differ from what the operator 18 personally prefers is when the controller 30 tries to return to the preferred lane after all of the various time-intervals have expired. If the controller 30 tries to initiate a lane-change to the preferred-lane, the operator 18 may take action to prevent that lane change. The operator 18 may be made aware of the controller preparing to make a lane change by a graphical-display in the host-vehicle 12 indicating that a lane-change is about to be initiated by the controller 30, or the controller may activate a turn-signal-indicator of the host-vehicle 12. That is, the controller 30 may be further configured to remain in the second-lane 42 for a third-time-interval 54 when the operator 18 overrides the lane-change to the first-lane 40 from the second-lane 42 that was initiated by the controller 30.
It follows that the controller 30 may be further configured to remain in the second-lane 42 after the third-time-interval 54 expires when a roadway-divergence 48 (e.g. exit ramp or fork in roadway 26) is located (e.g. detected by the object-detector 28 or indicated on digital-map 52) within a predefined-distance 50 of the host-vehicle 12 and until the roadway-divergence 48 is passed by the host-vehicle 12.
Returning to
It follows, as suggested above, the controller may be further configured to remain in the first-lane 40 after the fourth-time-interval 56 when a roadway-divergence 48 (exit ramp or fork in roadway 26) is located (detected by object-detector 28 or indicated on digital-map 52) within a predefined-distance 50 of the host-vehicle 12 and until the roadway-divergence 48 is passed by the host-vehicle 12.
Accordingly, a lane-keeping system (the system 10), a controller 30 for the system 10, and a method of operating the system 10 is provided. The system 10 and corresponding method provide for various time-intervals that controller 30 uses to better operate the host-vehicle 12 in accordance with the desires of the operator 18.
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.