Systems and methods of level 2 autonomous vehicle driving on multiply digitized roads

Autonomous driving techniques comprise determining a Form of Way (FOW) classification of a road along which a vehicle is traveling and when the determined FOW classification is FOW 1 or FOW 9, permitting level 2 autonomous driving of the vehicle. When the determined FOW classification is FOW 2, the techniques determine whether a set of operating conditions relating to autonomous driving satisfies a set of criteria that assesses a set of upcoming stubs along a future section of the road along which the vehicle will potentially travel are satisfied and when the set of criteria are satisfied, permitting level 2 autonomous driving of the vehicle and when the set of criteria are not initially satisfied or are subsequently no longer satisfied, not permitting or at least temporarily interrupting level 2 autonomous driving of the vehicle.

FIELD

The present application generally relates to autonomous vehicle driving and, more particularly, to systems and methods of level 2 autonomous vehicle driving on multiply or separately digitized roads.

BACKGROUND

Level 2 autonomous driving refers to partial driving automation where a vehicle provides assistance to steer, accelerate, and brake in certain circumstances, but a driver is always required to supervise the driving task. Level 2 autonomous driving could include, for example, a combination of adaptive cruise control and lane centering. Level 2 autonomous driving is often limited to certain types of roads, such as specific freeways and controlled access roads having defined entrance and exit ramps. The ERTICO ADASIS V2 protocol classifies these types of roads as Form-Of-Way (FOW) 1 and FOW 9 roads. Level 2 autonomous driving would also be desirable for use on multiply digitized roads, which are also identified as FOW 2 roads in the ERTICO ADASIS V2 protocol.

In a FOW 2 road, each side of the road is separately digitized and there is some sort of divider (a physical barrier, a curbed island area, a ditch, etc.) similar to a FOW 1 road. Additionally, a FOW 2 road may be punctuated by road crossings, traffic lights, or stub roads that butt up against the road and allow traffic to enter the roadway. A highway having a crossing road is one example of a FOW 2 road. Thus, while conventional autonomous driving systems do work well for their intended purpose, there remains a desire for improvement in the relevant art.

SUMMARY

According to one example aspect of the invention, an autonomous driving system for a vehicle is presented. In one exemplary implementation, the system comprises: a set of sensors configured to monitor a set of operating conditions relating to autonomous driving, a digitized maps module that stores digitized maps based on a defined protocol, and a controller configured to: determine a Form of Way (FOW) classification of a road along which the vehicle is traveling using the digitized maps module, when the determined FOW classification is FOW 1 or FOW 9, permit level 2 autonomous driving of the vehicle, when the determined FOW classification is FOW 2, determine whether the set of operating conditions satisfies a set of criteria, wherein the set of criteria assesses a set of upcoming stubs along a future section of the road along which the vehicle will potentially travel, when the set of operating conditions satisfies the set of criteria, permit level 2 autonomous driving of the vehicle, when the set of operating conditions fails to satisfy or no longer satisfies the set of criteria, not permit or at least temporarily interrupt level 2 autonomous driving of the vehicle, and when the determined FOW classification is none of FOW 1, FOW 2, and FOW 9 or the FOW classification of the road is otherwise indeterminable, not permit or disable level 2 autonomous driving of the vehicle.

In some implementations, the set of criteria includes a quantity of stubs in the set of stubs or a frequency of the set of stubs across a time period or distance being less than a quantity or frequency threshold. In some implementations, the set of criteria further includes a speed limit of the road derived from the digitized maps module or from a camera of the vehicle that reads speed signs being greater than a speed limit threshold. In some implementations, the set of criteria further includes at least one of a time and a distance until the vehicle reaches a first stub of the set of stubs being greater than respective thresholds. In some implementations, at least temporarily interrupting level 2 autonomous driving includes alerting a driver of the vehicle.

In some implementations, the controller is configured to resume level 2 autonomous driving after the temporary interruption in response to an action by the driver. In some implementations, at least temporarily interrupting level 2 autonomous driving includes at least temporarily disabling level 2 autonomous driving. In some implementations, the level 2 autonomous driving of the vehicle comprises a combination of adaptive cruise control (ACC) and lane centering. In some implementations, the road is classified as FOW 2 when it has two sides that are multiply or separately digitized and are divided by a physical barrier. In some implementations, the defined protocol the ERTICO ADASIS V. 2.0 protocol.

According to another example aspect of the invention, an autonomous driving method for a vehicle is presented. In one exemplary implementation, the method comprises: determining, by a controller of the vehicle and utilizing a digitized maps module that stores digitized maps based on a defined protocol, a Form of Way (FOW) classification of a road along which the vehicle is traveling, when the determined FOW classification is FOW 1 or FOW 9, permitting, by the controller, level 2 autonomous driving of the vehicle, when the determined FOW classification is FOW 2, determining, by the controller, whether a set of operating conditions relating to autonomous driving satisfies a set of criteria, wherein the set of criteria assesses a set of upcoming stubs along a future section of the road along which the vehicle will potentially travel, when the set of operating conditions satisfies the set of criteria, permitting, by the controller, level 2 autonomous driving of the vehicle, when the set of operating conditions fails to satisfy or no longer satisfies the set of criteria, not permitting or at least temporarily interrupting, by the controller, level 2 autonomous driving of the vehicle, and when the determined FOW classification is none of FOW 1, FOW 2, and FOW 9 or the FOW classification of the road is otherwise indeterminable, not permitting or disabling, by the controller, level 2 autonomous driving of the vehicle.

In some implementations, the set of criteria includes a quantity of stubs in the set of stubs or a frequency of the set of crossing roads across a time period or distance being less than a quantity or frequency threshold. In some implementations, the set of criteria further includes a speed limit of the road derived from the digitized maps module or from a camera of the vehicle that reads speed signs being greater than a speed limit threshold. In some implementations, the set of criteria further includes at least one of a time and a distance until the vehicle reaches a first stub of the set of stubs being greater than respective thresholds. In some implementations, at least temporarily interrupting level 2 autonomous driving includes alerting a driver of the vehicle.

In some implementations, the controller is configured to resume level 2 autonomous driving after the temporary interruption in response to an action by the driver. In some implementations, at least temporarily interrupting level 2 autonomous driving includes at least temporarily disabling level 2 autonomous driving. In some implementations, the level 2 autonomous driving of the vehicle comprises a combination of adaptive cruise control (ACC) and lane centering. In some implementations, the road is classified as FOW 2 when it has two sides that are multiply or separately digitized and are divided by a physical barrier. In some implementations, the defined protocol is the ERTICO ADASIS V. 2.0 protocol.

DETAILED DESCRIPTION

FIGS. 1A-1Dillustrates overhead views of example Form of Way (FOW) 1, 2, 9, and 10 classified roads per the ERTICO ADASIS V2 protocol. These are merely examples and the various FOW road classifications could have many different appearances. Referring first toFIG. 1A, FOW 1 and FOW 10 classified road portions are illustrated. The FOW 1 road portion is a controlled access freeway or interstate where the road is separated by a physical barrier, where each side of the roadway is digitized separately, and where the driver needs to travel over a defined or controlled access entrance or exit ramp in order to enter or exit the freeway. The FOW 10 road portion is the controlled access entrance and exit ramps of the FOW 1 road portion. Level 2 autonomous driving is appropriate for the FOW 1 road portion but is not allowed for the FOW 10 road portion because the driver needs to be in control of the entry or exit of the vehicle to/from the FOW 1 road portion via the FOW 10 portion.FIG. 1Billustrates an interchange between FOW 1 classified road portions in addition to FOW 9 classified road portions. The FOW 9 road portions are transitional ramps between different FOW 1 road portions that permit traffic to pass from one FOW 1 road to another FOW 1 road without crossing traffic streams. Level 2 autonomous driving is appropriate for the FOW 9 road portions as well as the FOW 1 road portions because such a series of road portions (FOW 1→FOW 9→FOW 1) is essentially the same as continuous travel along a FOW 1 road portion.

FIG. 1Cillustrates a FOW 2 classified road portion where there are two sides of the road that are multiply or separately digitized (e.g., separately stored and identifiable in a map system), some sort of divider therebetween (a physical barrier, a curbed island, a ditch, etc.), and potentially some crossing roads therealong. Level 2 autonomous driving would appropriate for some FOW 2 road portions, such as those having high speed limits and few or no crossing roads where the number of possible and probably situations is limited or lower than on other FOW 2 road portions. Some systems, however, typically do not permit any level 2 autonomous driving on FOW 2 classified roads. This approach involves “geo-fencing” that only permits level 2 autonomous driving in areas that are well-known to be FOW 1 and FOW 9 classified road portions. Lastly,FIG. 1Dillustrates a FOW 3 classified road portion, the best example of which is a typical undivided two-lane road portion. Level 2 autonomous driving is not appropriate on FOW 3 roads because the vehicles could potentially steer into the neighboring and opposing lane and into the path of oncoming vehicles.

Accordingly, improved autonomous driving systems and methods that provide for at least temporary level 2 autonomous driving on FOW 2 classified roads are presented. The extension of level 2 autonomous driving to FOW 2 road portions will allow for autonomous vehicle operation as most drivers would expect and thus could potentially improve the driver experience. Referring now toFIG. 2, a functional block diagram of a vehicle100having an example autonomous driving system104according to the principles of the present disclosure is illustrated. The vehicle100comprises a powertrain (e.g., an engine, an electric motor, or some combination thereof) that generates drive torque and transfers it to a driveline112to propel the vehicle100. A controller116controls operation of the vehicle100, e.g., based on driver input via an interface120and/or measurements or information from a set of one or more sensors124or similar devices (including, but not limited to, exterior cameras, radio detection and ranging (RADAR), light detection and ranging (LIDAR), vehicle speed sensors, a transceiver or radio receiving information, such as the FOW road classification, etc.). In addition to an accelerator pedal, brake pedal, and steering wheel, the interface120could further include, for example, a driver-facing camera, steering wheel hand contact sensors, steering torque sensing, and haptic, visual, and audible indications/alerts. A brake system128applies a braking force to the driveline112to decrease the speed of the vehicle100and a steering system132controls steering of the vehicle100. The controller116can also request torque from the powertrain, in order to increase the speed of the vehicle100.

The autonomous driving system104generally comprises the controller116, the interface120, the sensor(s)124, the brake system128, the steering system132, the powertrain system108, a GPS location/map matching system, and a digitized maps module136. Level 2 autonomous driving could comprise, for example only, a combination of adaptive cruise control (ACC) where the controller116controls acceleration and braking to maintain a desired speed and a desired distance from nearby vehicles and lane centering where the controller116controls steering to maintain the vehicle100traveling down the center of a lane of the road. It will be appreciated that level 2 autonomous driving could include combinations of additional or different features. It will be appreciated that the term “controller” as used herein refers to any suitable control device or set of multiple control devices that is/are configured to perform at least a portion of the techniques of the present disclosure. Non-limiting examples include an application-specific integrated circuit (ASIC), one or more processors and a non-transitory memory having instructions stored thereon that, when executed, cause the controller to perform a set of operations corresponding to at least a portion of the techniques of the present disclosure. The one or more processors could be either partitioned within a single processor or two or more processors operating in a parallel or distributed architecture.

The digitized maps module136, which could be part of a memory of the controller116or a separately accessible module, stores digitized maps that are primarily utilized to determine distances to upcoming crossing roads or stubs, which is described in greater detail below. The stored maps in the digitized maps module136could also include road classifications according to the ERTICO ADASIS V2 protocol.

Referring now toFIG. 3, an example overhead view of the vehicle100traveling along a FOW 2 classified road portion300is illustrated. The FOW 2 road portion comprises first and second multiply or separately digitized roads304aand304b, respectively. First road304acomprises two first lanes308aand308band is for travel in a first direction (right). Second road304bcomprises two second lanes308cand308dand is for travel in an opposing second direction (left). The first and second road304aand304bare separated by divider312(a physical barrier, a curbed island, a ditch, etc.). As shown, vehicle100is traveling in the first direction (right) along first lane308aof first road304aand other vehicles316aand316bare traveling in the opposing second direction (left) along second lanes308dand308c, respectively, of second road304b. The FOW 2 road300further comprises first and second stubs320aand320b. While the first stub320aonly connects to first road304a, the second stub320bis a crossing road that crosses over both the first and second roads304a,304bvia a gap322in the divider312. As shown, yet another vehicle324is waiting at a stop sign or traffic light326to turn onto the first road304aor to cross the first road304aand turn onto the second road304bvia the gap322, or to cross both the first and second roads304a,304band there is also another traffic light or stop sign328along the first road304aat the second stub320b. Thus, vehicle324could interfere with vehicle100or vice-versa. More specifically, if level 2 autonomous driving were on a conventional vehicle in place of vehicle100and/or vehicle324and its driver(s) was/were not paying attention or was/were distracted and vehicle324turned onto first road304aor crossed the first road304a, the conventional autonomous driving system could pass directly through an intersection or a grade crossing and vehicle100could strike vehicle324or vehicle324could strike vehicle100, especially if vehicle100were passing through a red traffic signal (e.g., by traffic light328) without stopping.

The autonomous driving system104of vehicle100monitors distance d1to the first stub320aand distance d2to the second stub320b(also referred to as stub offsets) using digitized maps from the digitized maps module136. A distance that the vehicle100has already traveled along road304a(also referred to as a vehicle offset) and distances of stubs320a,320bfrom the start of road304a(also referred to as stub offsets) could be determined. For example, distance d2to the second stub320bcould be calculated by subtracting this vehicle offset from the stub offset for the second stub320b, and then the time to reach the second stub320bcould be determined based on the calculated distance d2and the vehicle speed. The digitized maps module136is utilized because the distance to a next stub could be very far away (e.g., miles away) and thus could not be sensed by sensor(s)124. The autonomous driving system104could also monitor (e.g., using sensor(s)124) distances to other objects, such a distance to traffic light or stop sign328. For example, the distance traffic light or sign328could be indicative of how far the vehicle100has until potential obstacles could be encountered. Based on the known speed of the vehicle100, the times for it to reach these various points is also determinable. The autonomous driving system104also calculates or determines a set of crossing roads that the vehicle100will encounter in a future period, which could also be described as a crossing road quantity or frequency (e.g., one crossing road every 1000 feet or every 2 seconds).

Based on the times, distances, and/or the quantity or frequency of upcoming crossing roads, the autonomous driving system104could permit level 2 autonomous driving, could temporarily interrupt ongoing level 2 autonomous driving, or could not permit or could disable ongoing or future level 2 autonomous driving. The speed of the vehicle100also could be a primary factor in whether level 2 autonomous driving is permitted. For example, level 2 autonomous driving could be limited only to roads having speed limits greater than speed limit threshold, which are more characteristic of highways remote from urban areas where fewer stubs can be expected. The speed limit can be derived from the digitized maps in the digitized maps module136or from a camera (e.g., sensor(s)124) that reads speed limit signs. In one exemplary implementation, the autonomous driving system104permits level 2 autonomous driving when the quantity or frequency of crossing loads is less than a quantity or frequency threshold. The autonomous driving system104could further require that the time and/or distance to the next crossing road (i.e., crossing road320a) is greater than respective thresholds. These various conditions are also referred to herein as a “set of criteria for level 2 autonomous driving.” When any of the set of criteria are not satisfied, level 2 autonomous driving is either not permitted or is disabled or is at least temporarily interrupted. It will be appreciated that other information could also be leveraged in determining whether or not to permit level 2 autonomous driving, such as a current destination and corresponding route from the vehicle's navigation/global positioning satellite (GPS) system.

Temporary interruption of the level 2 autonomous driving could include alerting the driver of the vehicle100and/or temporarily disabling at least some of the level 2 autonomous driving functionality, thereby forcing the driver to assume more control of the vehicle100. For example only, ACC operation could continue but lane centering could be at least temporarily disabled. Alternatively, both functionalities could be at least temporarily disabled. The alerts provided to the driver could be audible, visual, and/or haptic alerts and are provided via the interface120. For example only, the alerts could instruct the driver to perform specific action(s) in order to maintain level 2 autonomous driving. This could include, for example only, instructing the driver to take control of the steering wheel and/or instructing the driver to move their visual focus to the scene in front of the vehicle100(e.g., if they were looking elsewhere, such as looking downward at a mobile device). Other actions could also be required, such as a touch input by the driver confirming that they are aware of the upcoming crossing roads that could require their intervention into the level 2 autonomous driving. If the required action is not taken by the driver, the autonomous driving system104could fully disable level 2 autonomous driving and could provide further alerts.

Referring now toFIG. 4, a flow diagram of an example autonomous driving method400according to the principles of the present disclosure is illustrated. At404, the autonomous driving system104(i.e., the controller116together with a digitally stored map from the digitized maps module136) determines a FOW classification of a road along which the vehicle100is traveling. At408, the controller116determines whether the determined FOW classification of the road is FOW 1 or FOW 9. When true, the method400proceeds to412where the controller116permits level 2 autonomous driving and the method400ends/returns to the start. When the determined FOW classification of the road is not FOW 1 or FOW 9, the method400proceeds to416. At416, the controller116determines whether the determined FOW classification is FOW 2. When false, or when the FOW classification of the road is otherwise indeterminable, the method400proceeds to420where the controller116does not permit level 2 autonomous driving and the method400ends/returns. When the determined FOW classification of the road is FOW 2, the method400proceeds to424.

At424, the controller116determines whether the speed limit of the road is greater than a speed limit threshold. When true, the method400proceeds to428. When false, the method400proceeds to420where the controller116does not permit level 2 autonomous driving and the method400ends/returns. At428, the controller116calculates or determines at least one of a time and a distance to the next crossing road or stub that the vehicle100will encounter and a quantity or frequency of a set of crossing roads or stubs that the vehicle100will encounter in a future time or distance. These calculations could take into account, for example only, vehicle speed, vehicle path, vehicle length, an angle at which the crossing road or stub meets the road, and a FOW classification of the crossing road or stub. At432, the controller116determines whether at least one of the time and distance until the next crossing road or stub is greater than respective time/distance thresholds and whether the quantity or frequency of the set of crossing roads or stubs is less than a quantity or frequency threshold.

When true, the method400proceeds to412where the controller116permits level 2 autonomous driving. Otherwise, the method400proceeds to436where the controller116determines whether level 2 autonomous driving is currently occurring. When false, the method400ends/returns. When true, the method400proceeds to440where the controller116at least partially interrupts level 2 autonomous driving, such as providing driver alert(s) and/or disabling at least some level 2 autonomous driving functionality. At optional444, the controller116determines whether a required driver action was taken such that level 2 autonomous driving can resume. When true, the method400proceeds to448where the controller116resumes level 2 autonomous driving and the method400ends/returns. When false, however, the method400proceeds to452where the controller116fully disables level 2 autonomous driving and optionally provides further driver alert(s) and the method400ends/returns.