Patent Application
20170001636
This disclosure generally relates to a system for automated operation of a host-vehicle, and more particularly relates to a system that determines when a rear-end collision is imminent, and then operates the host-vehicle in a manner selected to reduce the effect of a rear-end collision experienced by an operator of the host-vehicle.
Whiplash and other injuries can be suffered by occupants of a host-vehicle that is rear-ended by a rearward-vehicle approaching from behind the host-vehicle. Rear-end collisions are often the result of the operator of the rearward-vehicle tailgating and/or being distracted by, for example, a text message or a child in the rearward-vehicle. Ice covered roads that are undetected as being so by the operator of the rearward-vehicle can also lead to rear-end collisions. Unfortunately, the operator of the host-vehicle that is rear-ended often has no advanced warning or knowledge that the host-vehicle is about to be rear-ended, i.e. that a rear-end collision is imminent.
As vehicles become more automated, progressing from partially automated to fully automated where an operator of a host-vehicle is little more than a passenger, the vehicle systems that keep track of objects and other vehicles forward of and beside the host-vehicle can also keep track of traffic situations behind the host-vehicle, and take evasive or remedial action when rear-end collision is imminent. As used herein, the characterization of a rear-end collision as imminent includes situations when a rear-end collision is likely (e.g. greater than 50% probability) if no-action is taken by the host-vehicle (or operator thereof) that is about to be rear-ended, but could be avoided if some sort of action is taken; and situations when no possible action by the host-vehicle (or operator thereof) that is about to be rear-ended will avoid the rear-end collision. That is, the classification or characterization of a rear-end collision as imminent does not require that the rear-end collision is absolutely unavoidable, but does not exclude those situations. Described herein is a system for automated vehicles, either partially automated or fully automated (i.e. autonomous) that takes various actions with regard to acceleration/deceleration/steering of the host-vehicle to reduce the effect(s) of a rear-end collision experienced by an operator (occupant, passenger) of the host-vehicle. As will be described in more detail herein, an action taken by the host-vehicle may not prevent the rear-end collision, but may serve to lessen the impact and thereby reduce the effect(s) of a rear-end collision experienced by the operator of the host-vehicle.
In accordance with one embodiment, a system for automated operation of a host-vehicle is provided. The system includes a vehicle-control device, an object-detection device, and a controller. The vehicle-control device is operable to control one or more of acceleration of the host-vehicle, braking of the host-vehicle, and steering of the host-vehicle. The object-detection device is operable to detect a rearward-vehicle located behind the host-vehicle. The controller is configured to determine when the object-detection device indicates that a rear-end collision into the host-vehicle by the rearward-vehicle is imminent, and operate the vehicle-control device to reduce the effect of the rear-end collision experienced by an operator of the host-vehicle when the rear-end collision is imminent.
In accordance with one embodiment, a system for automated operation of a host-vehicle is provided. The system includes an object-detection device, and a controller. The object-detection device is operable to detect a rearward-vehicle located behind a host-vehicle. The controller is configured to determine when the object-detection devices indicates that a rear-end collision by the rearward-vehicle into the host-vehicle is imminent, and operate the host-vehicle to reduce the effect of the rear-end collision on an occupant of the host-vehicle when the rear-end collision is imminent.
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:
Accordingly, the system 10 includes an object-detection device 18 operable or useful to detect when the rearward-vehicle 16 is approaching the host-vehicle 14. The object-detection device 18 may include, but is not limited to a video camera, a radar unit, and/or a LIDAR unit suitably configured to detect various objects about the host-vehicle 14. Information gathered by the operation of the object-detection device 18 may be provided to a controller 20 for further analysis. That is, the object-detection device 18 may not by itself actually determine the location of or classification of the rearward-vehicle 16. Typically that task falls to the controller 20, but this is not a requirement of the system 10. In other words, either the object-detection device 18 or the controller 20 may perform the data or signal processing necessary to determine a relative location or classification of the rearward-vehicle 16.
The object-detection device 18 may also include a vehicle-to-vehicle (V2V) transceiver. If the rearward-vehicle 16 is another-vehicle that is also equipped with a V2V transceiver, then the system 10 may be able to notify the operator 12 that the rearward-vehicle 16 is approaching even if the operator 12 and the object-detection device 18 cannot see the rearward-vehicle 16 because the line of sight between the two is obstructed.
The controller 20 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 20 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 processing signals received by the controller 20 for operating the host-vehicle 14 as described herein.
The system 10 may include an operator-detection device 22 that is operable or useful to determine when the operator 12 of the host-vehicle 14 is aware of the rearward-vehicle 16. The operator-detection device 22 may include a camera configured to capture images of the operator 12 in the visible light spectrum and/or the infrared light spectrum, and a light source that emits light in a suitable portion of the light spectrum so the camera can see the operator 12 regardless of ambient lighting conditions. The images of the operator 12 may be processed/analyzed by the operator-detection device 22 or the controller 20 to, for example, determine if the operator 12 is farding, determine if the eyes of the operator 12 are closed indicating that the operator 12 is sleeping, determine if the head-pose of the operator varies in a manner that indicates that the operator 12 is tired, and/or determine if the eye-gaze direction of the operator 12 indicates that the operator 12 has or has not seen the rearward-vehicle 16. Image processing techniques to determine a cognitive state of the operator 12 such as where the operator is looking (eye-gaze direction) and/or if the operator 12 is alert (eye-blinking, head-pose variation) are well-known.
If the eye-gaze direction of the operator 12 is observed or determined via the operator-detection device 22 to not be in a direction that would allow the operator 12 to see the rearward-vehicle 16 directly, via a minor, or via peripheral vision, then that may be an indication that the operator 12 is not aware of the rearward-vehicle 16. If the system 10 determines that the operator 12 is not aware of the rearward-vehicle 16, and the relative location of the rearward-vehicle 16 relative to the host-vehicle 14 is such that a rear-end collision is possible, then the system 10 may take various actions to assist the operator 12 to avoid the collision with the rearward-vehicle 16.
In order for the controller 20 to be able to influence or control the position or trajectory of the host-vehicle 14 with respect to the rearward-vehicle 16 and other objects or other vehicles proximate to the host-vehicle 14, the system 10 includes a vehicle-control device 28 operable to control one or more of acceleration, braking, and steering of the host-vehicle 14. Multiple configurations of the vehicle-control device 28 are contemplated. For example, in one configuration the steering-wheel 40 may rotate as the controller 20 varies the steering direction of the host-vehicle. In this case, the system 10 may be configured so the operator 12 could physically overcome the intent of the controller 20 via the manual-controls 24.
Alternatively, the host-vehicle 14 may not have a steering-wheel or any means for the operator 12 to influence the steering direction of the host-vehicle 14. That is, the host-vehicle 14 may be configured to operate in a fully-automated or autonomous mode where the operator 12 of the host-vehicle 14 cannot influence the manual-controls 24 that control acceleration, braking, or steering of the host-vehicle 14, so the controller 20 may have total or absolute control of the manual-controls 24. As another alternative, the vehicle-control device 28 may include a control-override 26 be able to decouple the steering-wheel 40 from the steering mechanism that controls the steering direction of the host vehicle 14 and thereby override any attempt by the operator 12 to influence or otherwise steer the host-vehicle 14.
By way of example and not limitation, the control-override 26 of the vehicle-control device 28 may include one or more of an accelerator-control device 30 operable to over-ride operation of an accelerator-pedal 32 by an operator of the host-vehicle 14; a brake-control device 34 operable to over-ride operation of a brake-pedal 36 by the operator of the host-vehicle 14; and a steering-control device 38 operable to over-ride operation of a steering-wheel 40 by the operator of the host-vehicle 14.
With the information from the an object-detection device 18 to detect the rearward-vehicle 16 located behind the host-vehicle 14, the controller 20 may be equipped or programmed to determine or perform a rearward-vehicle-path analysis 56 to project a travel-path 42 of the rearward-vehicle 16 based on, but not limited to, a speed 44 and a trajectory 46 of the rearward-vehicle 16. This information may be provided to a rear-end-collision estimator 48 that determines if a rear-end collision is not imminent or is imminent.
It should be recognized that references to a rear-end collision does not mean that a collision has occurred. Rather, it means that circumstances are such that a rear-end collision is possible. As used herein, the characterization of a rear-end collision as imminent includes situations when a rear-end collision is likely (e.g. greater than 50% probability) if no intervening action is taken by the operator 12 or the host-vehicle 14 via the vehicle-control device 28. That is, a possible rear-end collision may be characterized as imminent even if the collision could be avoided by the operator 12 and/or the host-vehicle 14 taking some sort of intervening action. Also, situations when no possible action by the host-vehicle 14 or the operator 12 thereof will avoid the occurrence of a rear-end collision are characterized as imminent. That is, the classification or characterization of a rear-end collision as imminent does not require that the rear-end collision is absolutely unavoidable, but does not exclude those situations.
In addition to the controller 20 being configured to determine what the object-detection device 18 indicates about the rearward-vehicle, and the rear-end-collision estimator 48 indicates that a rear-end collision into the host-vehicle 14 by the rearward-vehicle 16 is imminent, the controller 20 may be advantageously configured to operate the vehicle-control device 28 to reduce the effect of the rear-end collision experienced by the operator 12 or passengers of the host-vehicle 14. That is, as will be explained in more detail below by way of several example traffic scenarios, the controller 20 may be configured or programmed to identify or consider a variety of optional actions that the controller 20 could execute via the vehicle-control device 28 to operate the host-vehicle 14 in a manner effective to reduce the likelihood of the rear-end collision actually occurring. Furthermore, if the pending rear-end collision is unavoidable, actions by the controller may operate the host-vehicle 14 in a manner that reduces the severity of the collision and thereby possibly reduce or prevent injury to the operator 12 and any passengers.
The system 10, or more specifically the object-detection device 18, may also be configured to detect a forward-vehicle-50 traveling in front of or beside the host-vehicle 14. The forward-vehicle 50 is generally distinguished from the rearward-vehicle 16 by the fact that the forward-vehicle 50 is not behind the host-vehicle 14. As will become apparent in the example traffic scenarios described below, the action that the controller 20 takes to prevent or avoid a rear-end collision, or reduce the severity of a rear-end collision, may in some circumstances need to includes some consideration or knowledge about the location of the forward-vehicle 50 relative to the host-vehicle 14.
In general, the controller 20 is configured to operate the vehicle-control device 28 to maintain a separation-distance 204 greater than a threshold-distance 52 (
While not subscribing to any particular theory, it has been suggested that the severity of a rear-end collision could be reduced if the controller 20 operated the host-vehicle to decrease the separation-distance 204 to less than the threshold-distance 52 when the rear-end collision is imminent. In the case where the host-vehicle 14 and the forward-vehicle 50 are both stopped, the controller 20 may be configured to operate the vehicle-control device 28 so the host-vehicle 14 makes contact with the forward-vehicle 50 when the rear-end collision is imminent, i.e. prior to the occurrence of the rear-end collision. If contact is made, the sudden acceleration experienced by the operator 12 at the moment of impact by the rearward-vehicle 16 may be decreased because the kinetic energy transferred from the rearward-vehicle 16 would be distributed to or shared by the host-vehicle 14 and the forward-vehicle 50. I.e. the combined mass of the host-vehicle 14 and the forward-vehicle 50, plus the multiple crush zones of the host-vehicle 14 and the forward-vehicle 50 that would cooperatively absorb the kinetic energy would serve to lessen the severity of the impact experienced by the operator 12.
In the case of the host-vehicle 14 and the forward-vehicle 50 traveling at about one hundred kilometers-per-hour (100 kph), the controller 20 may be configured to accelerate the host-vehicle 14 prior to the rear-end collision so the speeds of the host-vehicle 14 and the rearward-vehicle 16 were more closely matched at the time of impact. Having the speeds more closely matched would lessen the severity of impact, as will be recognized by those in the art. It is recognized that the timing and amount of acceleration by the host-vehicle 14 would need to consider the separation-distance 204 and the speeds of the host-vehicle 14 and the forward-vehicle 50.
Continuing to refer to
If the host-vehicle 14 is, for example, operating in a fully-automated mode, the controller may be configured to operate the vehicle-control device 28 to control a brake-pressure 58 of the host-vehicle 14 to a hold-pressure that is sufficient to keep the host-vehicle 14 stopped at the intersection 302 when a rear-end collision is not imminent. While not subscribing to any particular theory, it is believed that unnecessarily operating a vehicle brake-system at maximum-pressure to hold a vehicle stopped exposes the brake-system to unnecessary stress that may cause premature degradation of the brake-system. The controller 20 may be pre-programmed with the hold-pressure, or the hold-pressure may be learned by the controller 20 through experience. However, if information output by the object-detection device 18 and analyzed by the rearward-vehicle-path analysis 56 causes the rear-end-collision estimator 48 to determine that a rear-end collision is imminent, the controller 20 may operate the brake-control device 34 to increase the brake-pressure 58 to greater than the hold-pressure when the rear-end collision is imminent to keep the host-vehicle 14 stopped if the rear-end collision occurs. That is, the brake-pressure 58 is increased so the host-vehicle 14 is less likely to be pushed into the intersection 302 by the rearward-vehicle 16 if a rear-end collision occurs.
In general, the controller 20 is configured to operate the vehicle-control device 28 to operate the host-vehicle 14 in accordance with a traffic-regulation 60 (preferably all traffic regulations) when the rear-end collision is not imminent. That is, under normal circumstances the controller 20 is configured or programmed to obey traffic regulations. However, when the rear-end collision is imminent, it may be preferable for the controller 20 to operate the host-vehicle in a manner that is not in accordance with the traffic-regulation 60. For example, in the situation described above, the controller 20 is configured to operate the vehicle-control device 28 to stop the host-vehicle 14 at a stop-light 62 (e.g. the traffic-light 308 when the red-light R is displayed) when the rear-end collision is not imminent.
However, if there is no cross-traffic in or approaching the intersection 302 from directions perpendicular to the travel direction of the host-vehicle 14 and the rearward-vehicle 16, it may be preferable for the controller 20 to be configured to proceed through the stop-light 62 when the rear-end collision is imminent. That is, the controller 20 may be advantageously configured to operate the host-vehicle in accordance with a traffic-light-law (i.e. remain stopped at the intersection 302 when the traffic light 308 displays a red-light R) when the rear-end collision is not imminent, and ignore the traffic-light-law when stopped and the rear-end collision is imminent. For example, if the destination of the host-vehicle 14 necessitates traveling straight through the intersection 302, the controller 20 may operate the host-vehicle 14 to proceed through the intersection 302 even though the traffic-light is displaying a red-light R. Alternatively, for the same situation, the controller 20 may execute a right-turn if the rearward-vehicle-path analysis 56 indicates that proceeding straight will not be effective to avoid the rear-end collision because the host-vehicle 14 is unable to accelerate quickly enough to avoid the rear-end collision.
It is imagined that situations may arise when any action to reduce the effect of the rear-end collision experienced by an operator 12 of the host-vehicle 14 could cause an alternative collision. For example, and referring to
As such, the controller 20 may be advantageously configured to determine when any action to reduce the effect of the rear-end collision experienced by the operator 12 of the host-vehicle 14 will cause an alternative collision, e.g. contact with the other-vehicle 218, and select which action to take based on a multiple-collision-hierarchy 64. The multiple-collision-hierarchy 64 may include determining a collision-severity 66 for each collision, e.g. the pending rear-end collision and any alternative collisions that may arise by the host-vehicle 14 taking action to avoid the rear-end collision. The collision-severity 66 may be a numerical ranking assigned to each option based on a predicted or projected differential speed between the host-vehicle 14 and the vehicle involved in the predicted collision being analyzed.
The multiple-collision-hierarchy may also consider a time-to-collision 68 of the rear-end collision and/or any alternative collisions being analyzed. If the time-to-collision 68 of the rear-end collision is greater than the time-to-collision of any of the alternative collisions, the controller 20 may delay taking any action and hope that the rearward-vehicle 16 will recover control and/or slow down to reduce the severity of the rear-end collision. Contrariwise, if the time-to-collision 68 of the rear-end collision is less than the time-to-collision of one of the alternative collisions, e.g. changing lanes when an approaching-vehicle (not shown) is fast approaching in a projected location of the host-vehicle after the lane change is executed, then the controller 20 may execute the lane change and hope that the approaching-vehicle will be able to take some action to avoid or lessen the severity of the alternative collision caused by the lane change.
The system 10 may also include a warning-device 70 operable to provide a warning to the operator 12 that a rear-end collision is imminent. The warning may be visible, audible, or haptic such as vibrating the seat in which the operator 12 resides. The audible warning may be verbal such as “brace for impact” or informing the operator 12 of some pending action such as “changing lanes” or “braking”.
Accordingly, a system 10 for automated operation of a host-vehicle 14, and a controller 20 for the system 10 are provided. Since the operator 12 is often less aware of what is happening behind the host-vehicle 14 compared to what is happing in front of the host-vehicle 14 while manually operating the host-vehicle 14. While the various situations (traffic scenario 200, 300) are generally described as occurring during fully-automated operation of the host-vehicle 14, it is contemplated that the teachings presented herein are applicable during partial automation where the operator 12 may be manually operating the host-vehicle, and the controller 20 may temporarily take control of the host-vehicle 14 to execute an evasive maneuver or some maneuver to lessen the severity of rear-end collision. The system 10 and controller 20 described herein are particular advantageous because some maneuvers may be complicated and/or may exceed the driving skills of the operator 12, e.g. making contact with the forward-vehicle 50 without ramming the forward-vehicle 50. Furthermore, the system 10 never gets tired, distracted, or inattentive, as may be the situation with the operator 12, particularly in regard to imminent rear-end collisions.
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.
