Patent Description:
A lane departure warning technology for autonomous driving is critical to ensure autonomous driving. Most of current lane departure warning technologies of autonomous driving lie in lane departure warning (LDW) and lane keeping assist (LKA), which provide transverse control or warning only when a vehicle has departed from a lane. In the lane departure warning (LDW), warning is performed when a current camera detects that a vehicle is about to depart from a lane line. In the lane keeping assist (LKA), information is sent to a control center when a current camera detects that a vehicle is about to depart from a lane line, and then the control center sends an instruction for timely correction of a traveling direction. An existing technology also provides transverse control over a vehicle, and its main manner is that, in most cases, in the case of lane departure during lane keeping support (LKS), the LKS is exited.

The prior art cannot provide, based on a lane departure degree or risk, a warning prompt that is more applicable to a scene and an emergency degree and that is associated with operations of a driver.

<CIT> relates to a warning device which includes a distance acquisition unit that acquires a lane width direction distance between two lane boundary lines of a driving lane and a vehicle; a speed acquisition unit that acquires a lane width direction speed of the vehicle toward the lane boundary lines; a safety threshold setting unit that sets a safety threshold for allowing that the lower the lane width direction speed is toward the lane boundary lines, the smaller the lane width direction distance is; and a warning unit that warns a driver of the vehicle when the lane width direction distance is smaller than the safety threshold, wherein the safety threshold setting unit sets the safety threshold based on a history of the lane width direction distance and the lane width direction speed for a traveling environment of the vehicle.

In view of the foregoing problem, the invention is intended to provide a lane departure warning method and a lane departure warning system, which can estimate a lane departure status of a vehicle and perform timely warning.

An aspect of the invention provides a lane departure warning method, including:.

The warning area calculation step includes:.

Optionally, in the departure value calculation substep, the departure value of the lane line is calculated based on any one of the following, or the departure value of the lane line is a sum of any two or more of the following:.

Optionally, in the departure value calculation substep,.

Optionally, in the decision making step, whether the driver exerts a torque greater than a specified threshold on the steering wheel is determined, if it is determined that the driver exerts the torque greater than the specified threshold on the steering wheel, autonomous driving navigation is exited, and if it is determined that the driver does not exert the torque greater than the specified threshold on the steering wheel, whether lane departure of the vehicle occurs is determined based on the modified lane line.

Optionally, in the decision making step, a decision instruction for performing warning at different intensities is output based on the departure value of the lane line.

An aspect of the invention provides a lane departure warning system, including:.

The warning area calculation apparatus includes:.

Optionally, the departure value calculation submodule includes any one or more of the following departure value calculation modules:.

Optionally, the first departure value calculation module uses, as the departure value of the lane line based on a preset correspondence between a lane width and a departure value of the lane line, a corresponding departure value of the lane line that is obtained based on a current lane width from the correspondence,.

Optionally, the decision making apparatus determines whether the driver exerts a torque greater than a specified threshold on the steering wheel, if it is determined that the driver exerts the torque greater than the specified threshold on the steering wheel, exits autonomous driving navigation, and if it is determined that the driver does not exert the torque greater than the specified threshold on the steering wheel, determines, based on the modified lane line, whether lane departure of the vehicle occurs.

Optionally, the decision making apparatus outputs, based on the departure value of the lane line, a decision instruction for performing warning at different intensities.

Further described is a vehicle, including the foregoing lane departure warning system.

Further described is a computer-readable medium having a computer program stored thereon, where the computer program implements, when executed by a processor, the foregoing lane departure warning method.

Further described is a computer device, which includes a storage module, a processor, and a computer program stored on the storage module and executable on the processor, where when executing the computer program, the processor implements the foregoing lane departure warning method.

Some of the embodiments of the invention are described below and are intended to provide a basic understanding of the invention. They are not intended to confirm key or decisive elements of the invention or limit the scope of protection.

For concise and illustrative purposes, this specification mainly describes the principles of the invention with reference to its exemplary embodiments. However, those skilled in the art will readily recognize that the same principles can be equivalently applied to all types of lane departure warning methods and lane departure warning systems, and the same principles can be implemented therein.

In addition, in the following description, reference is made to the accompanying drawings, which illustrate specific exemplary embodiments. Electrical, mechanical, logical, and structural changes can be made to these embodiments without departing from the spirit and scope of the invention. Furthermore, although the features of the invention are disclosed in combination with only one of several implementations/embodiments, if any given or recognizable function may be desired and/or advantageous, this feature can be combined with one or more other features of other implementations/embodiments. Therefore, the following description should not be considered in a limiting sense, and the scope of the invention is defined by the appended claims.

The terms such as "have" and "include" indicate that in addition to the units (modules) and steps that are directly and clearly described in the specification and the claims, other units (modules) and steps that are not directly or clearly described are not excluded in the technical solutions of the invention.

The invention relates to a lane departure warning method and a lane departure warning system, and in particular, to transverse control of autonomous driving. The main technical idea includes: firstly calculating a warning area for lane departure of a vehicle in real time based on information about the vehicle and information about an environment around the vehicle, for example, obtaining a lane line (that is, an original lane line) from sensors of the vehicle, calculating a departure value of the lane line, modifying the lane line based on the departure value of the lane line to obtain a modified lane line, and using, as the warning area for lane departure of the vehicle, an area defined by the modified lane line; and then comparing a current position of the vehicle with the warning area of the vehicle to learn whether the vehicle enters the warning area for lane departure of the vehicle, and if it is learned that the vehicle enters the warning area for lane departure of the vehicle, giving a warning to prompt a driver.

Before the lane departure warning method and the lane departure warning system of the invention are described, an ADAS of the vehicle is briefly described first.

The advanced driving assistance system (ADAS) uses a variety of sensors (such as a millimeter-wave radar, a laser radar, a monocular/binocular camera, and satellite navigation) mounted on an automobile to sense the surrounding environment at any time during traveling of the automobile, collect data, identify, monitor, and track a still/moving object, and perform system operations and analysis in combination with navigation map data, allowing for a driver to be aware of potential dangers in advance, thereby effectively improving the comfort and safety of the automobile during traveling.

<FIG> is a schematic structural diagram of an example of an ADAS to which a lane departure warning system according to the invention is applied.

As shown in <FIG>, a control system of the ADAS is connected to a camera, radar, a vehicular communication unit (VCU), a battery control unit (BCU), a steering control module (SCM), an auxiliary control module (ACM), a continuous damping control (CDC) system, an electric power steering (EPS) system, and other sensors, actuators, or controllers through a CAN bus, for information exchange.

The ADAS obtains information about a road, a road sign, and other vehicles by using the camera, the radar, and other sensors, and obtains information about a vehicle such as a speed, an acceleration, a gear, steering, a transverse control moment of a driver, a selected mode, and a fault by using the VCU, the BCU, the SCM, the ACM, the EPS, and the CDC. The ADAS allows a driver to always know a working status of the vehicle and conducts information exchange with the vehicle by using information such as a warning of the CDC, a current activation mode, and a lane. When a transverse control system of the vehicle is started, the ADAS outputs a target turning angle or target steering torque request to the EPS in real time to control steering of the vehicle, and replaces the driver to control the steering.

The ADAS includes two critical control systems: a longitudinal control system and a transverse control system. Only lane departure warning in transverse control is involved in the invention. As shown by the box "Transverse control" in <FIG>, after signal processing (for example, filtering, validity determination, and fault diagnosis) is performed on an input signal, a warning area for lane departure is calculated based on the processed input signal and output to a decision making apparatus, and the decision making apparatus makes a decision, for example, a decision for transverse control or a decision for warning intervention.

The following describes the lane departure warning method of the invention.

<FIG> is a schematic flowchart of a lane departure warning method according to an implementation of the invention.

As shown in <FIG>, the lane departure warning method of the invention mainly includes the following steps:.

The warning area calculation step S <NUM> may further include:.

Then, specific content of how to obtain a departure value of a lane line in the departure value calculation substep S <NUM> is described.

In the invention, the departure value of the lane line is obtained to modify the original lane line and obtain a modified lane line, the warning area for lane departure is defined by the modified lane line (that is, going beyond the modified lane line means that the vehicle enters the warning area for lane departure),
and lane departure is subsequently determined based on the warning area for lane departure.

<FIG> is a schematic diagram of calculation of a warning area for lane departure in a lane departure warning method according to the invention. As shown in <FIG>, a straight line on the left side represents an original left lane line, and a shadow area around the straight line represents a warning area for lane departure on the left side. Likewise, a straight line on the right side represents an original right lane line, and a shadow area around the straight line represents a warning area for lane departure on the right side. The "warning area for lane departure" is defined by the modified lane line that is obtained by modifying the original left/right lane line based on the departure value of the lane line.

In the invention, the warning area for lane departure on the left side and the warning area for lane departure on the right side are calculated in the same calculation method. The following gives a description by using the warning area for lane departure on the left side as an example. The calculation method for the right side is the same, and description is omitted herein.

In the lane departure warning method and the lane departure warning system of the invention, the warning area for lane departure is estimated in real time based on one or more of the following: a transverse acceleration of a vehicle, a current lane width, a road curvature, a transverse velocity relative to a lane, a torque exerted by a driver on a steering wheel, and the like.

Specifically, in the lane departure warning method and the lane departure warning system of the invention, preferably, the warning area DleftWarnZn for lane departure on the left side may, for example, be calculated according to the following formula (<NUM>): <MAT>.

Herein, DwL is a departure value of the lane line that is calculated based on a lane width;.

As shown in formula (<NUM>), when the lane width increases, the warning area is appropriately shifted to the inner side of the road, such that the vehicle does not frequently perform warning in a narrow road and can perform timely warning in a wide road (corresponding to DwL). When the transverse acceleration of the vehicle toward the outer side of the lane increases, the vehicle is more likely to depart from the lane. The warning area is moved to the inner side of the road, so that early warning is performed, and the driver has more time to take over. For a curved lane, whether the warning area is moved inward to the center of the lane is determined based on a curvature of the outer side of a curve (the side away from a center of the curve) (corresponding to DCurv); and whether the warning area is moved outward is determined based on the transverse velocity of the vehicle relative to the lane, so that false warning is prevented (corresponding to DRelLatSpd).

In another aspect, six parameters are used when the warning area DleftWarnZn for lane departure on the left side is calculated according to the foregoing formula. This is merely a preferred implementation. In actual applications, any one or more of the six parameters can be selected for calculation, which shall fall within the protection scope of the invention. The warning area for lane departure on the right side and the warning area for lane departure on the left side are calculated in the same calculation method. Description is omitted herein.

Then, calculations of the departure values in six scenarios represented by the six parameters are described in detail.

DwL is a departure value of the lane line that is calculated based on a lane width. <FIG> is a lane width graph showing a correspondence between DwL and a lane width wL. DwL is obtained based on the lane width graph shown in <FIG>. The lane width graph may be preset, or may be updated and adjusted in real time according to an actual situation. As shown in <FIG>, the transverse axis represents the lane width wL, and the longitudinal axis represents DwL. When the lane width wL increases, DwL increases. Then, the warning area is appropriately shifted to the inner side of the lane, such that the vehicle can also perform timely warning in a wide road and does not frequently perform warning in a narrow road. Herein, the lane width is calculated based on information about the left lane line and the right lane line that is input by a visual system.

DCurv is a departure value of the lane line that is calculated based on a lane curvature. <FIG> is a schematic diagram showing a relationship between DCurv and a road curvature. DCurv means that whether the warning area is moved outward or inward relative to the center of the lane is calculated based on a value of the road curvature. In an example of a leftward curve, as shown in <FIG>, the warning area on the right side of D1 is moved toward the center of the lane (moved inward) by a specific distance, and the warning area on the left side of D2 in <FIG> is moved to the outer side of the center of the lane (moved outward) by a specific distance. The road curvature is from the visual system of the vehicle. In the design of the invention, the warning area is moved closer to the curve center when the curvature increases, such that warning can be performed earlier.

DLatA is a departure value of the lane line that is calculated based on a transverse acceleration of the vehicle. Herein, the warning area is calculated based on the transverse acceleration (the transverse acceleration is from an air-bag control module (ACM)) by using the example of the leftward curve. Still referring to the example of the leftward curve in <FIG>, if there is a deviation between the actual transverse acceleration of the vehicle and an expected transverse acceleration for passing the curve, the warning area is modified based on the deviation value. If the current transverse acceleration (absolute value) of the vehicle is less than an acceleration for normal traveling in a curve, this means that the vehicle is more likely to depart from the center of the lane. In this case, the area D1 needs to be expanded and the area D2 needs to be narrowed or kept unchanged in <FIG>. If the current transverse acceleration (absolute value) of the vehicle is greater than an acceleration for normal traveling in a curve, this means that the vehicle is more likely to depart to the left side of the lane. In this case, the area D2 needs to be expanded and the area D1 needs to be narrowed or kept unchanged in <FIG>.

The foregoing content can be understood as: The departure value of the lane line that is calculated based on the transverse acceleration of the vehicle means that if an actual transverse acceleration of the vehicle is less than an expected transverse acceleration for passing a curve, the lane line on the outer side of the curve is moved inward, and the lane line on the inner side of the curve is unchanged or moved inward; or if the actual transverse acceleration of the vehicle is greater than the expected transverse acceleration for passing the curve, the lane line on the inner side of the curve is moved outward, and the lane line on the outer side of the curve is unchanged or moved outward.

DRelLatSpd is a departure value of the lane line that is calculated based on a transverse velocity of the vehicle relative to a lane. <FIG> is a schematic diagram showing a relationship between DRelLatSpd and a transverse velocity of a vehicle. As shown in <FIG>, in a current state, the vehicle with its head facing rightward is more likely to depart from a lane to the right side. Therefore, a distance of moving a warning area on the right side to the inner side of the lane is calculated based on a value of the transverse velocity as shown in D1 in <FIG>, so that warning is performed earlier, and a driver has sufficient time to take over. However, the vehicle is less likely to depart from the lane to the left side. Therefore, a warning area on the left side is moved outward, so that false warning is reduced.

The foregoing content can be understood as: The departure value of the lane line that is calculated based on the transverse velocity of the vehicle relative to the lane means that if the vehicle head faces the right side of the lane, the lane line on the right side is moved inward by a specified distance, and the lane line on the left side is moved outward by a specified distance; or if the vehicle head faces the left side of the lane, the lane line on the left side is moved inward by a specified distance and the lane line on the right side is moved outward by a specified distance.

DOvrd is a departure value of the lane line that is calculated based on operations of a driver on a steering wheel (torque). <FIG> is a schematic diagram showing a relationship between DOvrd and operations of a driver on a torque. DOvrd means that a warning area is modified based on the operations of the driver on the steering wheel (that are determined by using a steering wheel torque signal provided by the EPS) to obtain a departure value of a lane line so as to modify the lane line.

As shown in <FIG>, if the driver actively exerts a specific torque on the steering wheel and causes a vehicle to depart from a lane, the departure value of the lane line is adjusted based on a value of the torque exerted by the driver on the steering wheel. If the input of the driver causes the vehicle to drive toward the center of the lane, the value of the input of the driver on the steering wheel is determined, and the warning area on the side from which the vehicle is getting away is narrowed. As shown in <FIG>, because a rightward torque is increased on the steering wheel, the warning area on the left side is narrowed.

The foregoing content can be understood as: The departure value of the lane line that is calculated based on the operations of the driver on the steering wheel (torque) means that if the driver increases the rightward torque on the steering wheel, the lane line on the left side is moved outward by a specified distance; or if the driver increases a leftward torque on the steering wheel, the lane line on the right side is moved outward by a specified distance.

DSojurn is a departure value of the lane line that is calculated based on a staying time of the vehicle.

<FIG> is a schematic diagram showing a relationship between DSojurn and a staying time of a vehicle. As shown in <FIG>, if the vehicle stays on one side for a long time and up to a specific time, and there is no further tendency for outward departure, the area is moved outward and the warning area is narrowed.

The foregoing content can be understood as: The departure value of the lane line that is calculated based on the staying time of the vehicle means that if the staying time of the vehicle is greater than a preset threshold and there is no further tendency for outward departure, the lane line on the vehicle stop side is moved outward by a specified distance.

The foregoing describes specific content of calculating the warning area for lane departure according to formula (<NUM>). The departure value of the lane line can be calculated to modify the original lane line to obtain a calculation result of the warning area for lane departure. After that, whether the vehicle enters the warning area can be learned by comparing a current position of the vehicle with the warning area for lane departure.

<FIG> is a structural block diagram of a lane departure warning system according to an implementation of the invention.

As shown in <FIG>, the lane departure warning system according to an implementation of the invention includes:.

The warning area calculation apparatus <NUM> includes:.

In a preferred example, the departure value calculation submodule <NUM> includes any one or more of a first departure value calculation module <NUM> to a sixth departure value calculation module <NUM> in the following:.

The following describes specific functions of the first departure value calculation module <NUM> to the sixth departure value calculation module <NUM>.

The first departure value calculation module <NUM> uses, as the departure value of the lane line based on a preset correspondence between a lane width and a departure value of the lane line, a corresponding departure value of the lane line that is obtained based on a current lane width from the correspondence.

The second departure value calculation module <NUM> calculates, as the departure value of the lane line based on a value of a road curvature, a specified distance of moving the original lane line outward or inward relative to the center of the lane.

When an actual transverse acceleration of the vehicle is less than an expected transverse acceleration for passing through a curve, the third departure value calculation module <NUM> calculates a specified distance of moving the original lane line on an outer side of the curve inward as the departure value of the lane line, with a departure value of the original lane line on an inner side of the curve being <NUM>, or calculates a specified distance of moving the original lane line on the inner side of the curve inward as the departure value of the lane line; or when the actual transverse acceleration of the vehicle is greater than the expected transverse acceleration for passing through the curve, the third departure value calculation module calculates a specified distance of moving the original lane line on the inner side of the curve outward as the departure value of the lane line, with a departure value of the original lane line on the outer side of the curve being <NUM>, or calculates a specified distance of moving the original lane line on the outer side of the curve outward as the departure value of the lane line.

When a vehicle head faces a right side of the lane, the fourth departure value calculation module <NUM> calculates a specified distance of moving the original lane line on the right side inward or a specified distance of moving the original lane line on a left side outward as the departure value of the lane line; or when the vehicle head faces the left side of the lane, the fourth departure value calculation module calculates a specified distance of moving the original lane line on the left side inward or a specified distance of moving the original lane line on the right side outward as the departure value of the lane line.

When the driver increases a rightward torque on a steering wheel, the fifth departure value calculation module <NUM> calculates the specified distance of moving the original lane line on the left side outward as the departure value of the lane line; or when the driver increases a leftward torque on the steering wheel, the fifth departure value calculation module calculates the specified distance of moving the original lane line on the right side outward as the departure value of the lane line.

When the staying time of the vehicle is greater than a preset threshold and there is no further tendency for outward departure, the sixth departure value calculation module <NUM> calculates a specified distance of moving the original lane line on a vehicle stop side outward as the departure value of the lane line.

In an alternative implementation, the decision making apparatus <NUM> can further determine operations of the driver on the steering wheel. <FIG> is a schematic flowchart showing decision making and determination of an alternative implementation of a decision making apparatus.

As shown in <FIG>, the decision making apparatus determines a torque exertion status of a driver on a steering wheel, and specifically determines whether the driver obviously performs override (for example, exerting a torque greater than a specified threshold). When the decision making apparatus determines a degree at which the driver obviously performs override on the steering wheel and determines that the driver has an obvious intention to control the steering wheel, a decision making result for exiting an LKS is sent to exit transverse control and allow the driver to take over transverse control. When determining that the driver does not obviously perform override on the steering wheel, the decision making apparatus further determines whether the vehicle enters the warning area for lane departure (that is, determining, based on the modified lane line, whether the vehicle departs from the lane). If the vehicle enters the warning area for lane departure, a warning prompt is sent while transverse control is kept, otherwise processing ends.

The warning apparatus <NUM> is configured to perform a warning action based on the decision making result output by the decision making apparatus. For example, the warning module is configured to output response sound or light to warn the driver that the vehicle is about to depart from the lane. Further, if the vehicle still departs from the center of the lane after the prompt, when the vehicle increasingly departs from the lane, the warning sound is sent at an increasingly higher frequency to prompt the driver more obviously as shown in <FIG> is a schematic diagram of an example showing warning sound frequency changes of a warning module. <FIG> shows that the frequency of the warning sound of the warning module is increased as the vehicle increasingly departs from the lane.

Further, in an alternative implementation, if the decision making apparatus <NUM> determines that the vehicle still departs from the lane after the warning is performed by the first warning method such as sound and light, the decision making apparatus <NUM> further sends a decision instruction and causes the warning apparatus <NUM> to add a second warning method such as vibration of the steering wheel and vibration of a seat for a more obvious prompt. If the decision making apparatus <NUM> determines that the vehicle still departs from the lane under the action of these warning methods, when the middle line of the vehicle goes beyond the original lane line, the decision making apparatus <NUM> sends a decision instruction to exit transverse control.

According to the lane departure warning method and the lane departure warning system of the invention, the departure value of the original lane line is calculated to modify the original lane line and obtain a modified lane line, and the modified lane line is used to determine whether the vehicle departs from the lane, so that lane departure of the vehicle can be more accurately estimated and timely warning can be performed when there is a tendency for lane departure.

The invention further provides a vehicle, including the foregoing lane departure warning system.

The invention further provides a computer-readable medium having a computer program stored thereon, where the computer program implements, when executed by a processor, the foregoing lane departure warning method.

The invention further provides a computer device, which includes a storage module, a processor, and a computer program stored on the storage module and executable on the processor, where when executing the computer program, the processor implements the foregoing lane departure warning method.

Claim 1:
A lane departure warning method, comprising:
a warning area calculation step (S100) in which a warning area for lane departure of a vehicle is calculated based on information about the vehicle and information around the vehicle;
a decision making step (S200) in which a current position of the vehicle is compared with the warning area calculated in the warning area calculation step, to determine whether the vehicle is located in the warning area and output a decision instruction; and
a warning step (S300) in which a warning action is performed based on the decision instruction,
wherein
the warning area calculation step comprises:
a departure value calculation substep (S101) for obtaining a departure value of a lane line, which is a departure value calculated based on a transverse acceleration of the vehicle, or is a departure value calculated based on a staying time of the vehicle, or is a sum of the departure value calculated based on the transverse acceleration of the vehicle and the departure value calculated based on staying time of the vehicle; and
a warning area modification substep (S102) in which the original lane line is modified based on the departure value of the lane line calculated in the departure value calculation substep, to obtain a modified lane line, and an area defined by the modified lane line is used as the warning area for lane departure of the vehicle.