Lane departure warning device, lane departure warning method, and program

Abstract

The position information of the target vehicle is acquired on the basis of the measurement results of a sensor mounted on the target vehicle, and includes the horizontal position and the vertical position of the target vehicle. A position reliability calculation method for calculating reliability of position information of a target vehicle includes: (A) acquiring, as a sensor-based height, a height of a representative point at a horizontal position of the target vehicle on the basis of a vertical position included in the position information; (B) acquiring the height of a representative point at the horizontal position of the target vehicle as the height based on a height map showing the correspondence of the latitude, longitude, and height of the road surface; and (C) calculating the reliability such that the reliability becomes lower as the deviation between the sensor-based height and the map-based height becomes larger.

Description

Technical Field

[0001] This disclosure relates to lane departure warning devices, lane departure warning methods, and procedures. Background Technology

[0002] As a driver assistance control for vehicles, lane departure warning control (hereinafter referred to as LDA control) is known to suppress a vehicle from deviating from its driving lane. For example, Patent Document 1 discloses a technique in which LDA control is executed earlier when it is determined that the driver is releasing the handrail, compared to when it is determined that the driver has not released the handrail.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2023-082251 Summary of the Invention

[0006] In vehicle driver assistance control, in addition to LDA control mentioned above, there is also Lane Trace Assist Control (LTA control), which keeps the vehicle in its driving lane. Both LDA and LTA controls issue lane departure warnings when the vehicle deviates from or is about to deviate from its driving lane. Therefore, when LTA-based and LDA-based lane departure warnings operate in parallel, both types of warnings are generated continuously, which can be annoying to the driver.

[0007] The technology disclosed herein was developed to solve the aforementioned problems, with the aim of effectively suppressing the continuous generation of two lane departure warnings.

[0008] The disclosed technology is a lane departure warning device that provides an alert when a vehicle deviates from or is about to deviate from its lane, the lane departure warning device comprising:

[0009] The first alarm unit, during the execution of lane keeping control to keep the vehicle in the lane, determines whether there is a possibility that the vehicle may deviate from the lane, and implements a first deviation alarm when it determines that there is a possibility of deviation.

[0010] The second warning unit, while the vehicle is in motion, determines whether there is a possibility that the vehicle may deviate from the lane, and when it determines that there is a possibility of deviation, implements steering control to suppress the vehicle from deviating from the lane and a second lane departure warning; and

[0011] The priority processing unit performs priority processing during the execution of the lane keeping control, prioritizing the implementation of the steering control and / or the second departure warning by the second alarm unit over the implementation of the first departure warning by the first alarm unit. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating the hardware configuration of the vehicle involved in this embodiment.

[0013] Figure 2 This is a schematic diagram illustrating the software configuration of the control device involved in this embodiment.

[0014] Figure 3 This is a schematic diagram illustrating LDA control.

[0015] Figure 4 This is a schematic diagram illustrating the LDA priority processing involved in this embodiment.

[0016] Figure 5 This is a schematic diagram illustrating an existing example.

[0017] Figure 6 This is a flowchart illustrating the routine for LDA priority processing involved in this embodiment. Detailed Implementation

[0018] Hereinafter, the lane departure warning device, lane departure warning method and procedure involved in this embodiment will be described with reference to the accompanying drawings.

[0019] [Hardware Components]

[0020] Figure 1 This is a schematic diagram illustrating the hardware configuration of the vehicle VH according to this embodiment.

[0021] The vehicle (VH) has an ECU (Electronic Control Unit) 10. The ECU 10 includes a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, and an interface device 14. The CPU 11 is a processor that executes various programs stored in the ROM 12. The ROM 12 is non-volatile memory that stores data required by the CPU 11 to execute various programs. The RAM 13 is volatile memory that provides the operating area when the CPU 11 executes various programs. The interface device 14 is a communication device for communicating with external devices.

[0022] ECU 10 is the central device for performing driving assistance functions such as LDA control and LTA control. Driving assistance includes the concept of autonomous driving. Drive unit 20, braking unit 21, steering unit 22, interior sensor unit 30, exterior sensor unit 40, HMI (Human Machine Interface) 60, etc., are connected to ECU 10 in a communicative manner.

[0023] The drive unit 20 generates a driving force that is transmitted to the drive wheels of the vehicle VH. Examples of drive units 20 include electric motors and engines. The braking unit 21 applies braking force to the wheels of the vehicle VH.

[0024] The steering mechanism 22 applies steering force to the wheels of the vehicle VH. The steering mechanism 22 can be either a rack and pinion type or a steer-by-wire type. The steering mechanism 22 has a steering operation unit 23 including a steering wheel SW. Additionally, the steering mechanism 22 includes a steering motor 25 that imparts steering torque to the steering shaft 24. The steering motor 25 generates steering torque according to commands from the ECU 10. This steering torque enables the left and right steering wheels of the vehicle VH to be steered. Furthermore, the steering operation unit 23 is not limited to a steering wheel SW and can be a steering stick or other shape besides a steering wheel.

[0025] The interior sensor device 30 is a sensor group that detects the vehicle's VH (vehicle speed, steering angle, and steering torque) state. Specifically, the interior sensor device 30 includes a vehicle speed sensor 31, a steering angle sensor 32, a steering torque sensor 33, a yaw rate sensor 34, and an acceleration sensor 35.

[0026] Vehicle speed sensor 31 detects the vehicle speed (V) of vehicle VH. Steering angle sensor 32 detects the rotation angle of the steering wheel SW or steering shaft 24 of vehicle VH, i.e., steering angle σD. Steering torque sensor 33 detects the rotational torque of the steering wheel SW or steering shaft 24, i.e., steering torque Tq. Yaw rate sensor 34 detects the yaw rate of vehicle VH. Acceleration sensor 35 detects the acceleration of vehicle VH. The interior sensor device 30 sends the vehicle VH status detected by each sensor 31 to sensor 35 to the ECU 10 at predetermined intervals.

[0027] The external sensor device 40 is a group of sensors that identifies landmark information related to objects around the vehicle VH. Specifically, the external sensor device 40 includes a radar sensor 41, a camera sensor 42, etc. Here, landmark information can include, for example, surrounding vehicles, road markings such as white lines drawn on the road surface, curbs, guardrails, walls, etc.

[0028] Radar sensor 41 detects objects present around the vehicle VH. Radar sensor 41 includes millimeter-wave radar and / or lidar. The millimeter-wave radar emits millimeter-wave radio waves (millimeter waves) and receives millimeter waves (reflected waves) reflected by objects present within its emission range. Based on the phase difference between the emitted and received millimeter waves, the attenuation level of the reflected waves, and the time from the emission of the millimeter waves to the reception of the reflected waves, the millimeter-wave radar obtains the relative distance and relative speed between the vehicle VH and the objects. The lidar sequentially scans pulsed laser light with wavelengths shorter than millimeter waves in multiple directions and receives reflected light from objects, thereby obtaining the shape of objects detected in front of the vehicle VH, the relative distance and relative speed between the vehicle VH and the objects.

[0029] Camera sensor 42 acquires object information about the vicinity of vehicle VH by capturing images of the area around the vehicle VH and processing the captured image data. For example, a digital camera with imaging elements such as CMOS or CCD can be used as camera sensor 42. Object information includes information such as the type of object detected around vehicle VH, the relative distance between vehicle VH and the object, and the relative speed between vehicle VH and the object. The type of object can be identified, for example, through machine learning such as pattern matching.

[0030] The external sensor device 40 repeatedly sends the acquired target information to the ECU 10 at predetermined intervals. The ECU 10 determines the relative relationship between the vehicle's VH and the target by synthesizing the relative relationship between the vehicle's VH and the target obtained by the radar sensor 41 and the relative relationship between the vehicle's VH and the target obtained by the camera sensor 42. Furthermore, the external sensor device 40 does not necessarily need to include both the radar sensor 41 and the camera sensor 42; for example, it may only include the camera sensor 42.

[0031] HMI 60 is an interface for inputting and outputting information between ECU 10 and the driver, and includes input and output devices. Input devices may include an LTA start switch 61, a touch panel, and a sound-collecting microphone. The LTA start switch 61 is a switch that allows the driver to select whether to start or stop the LTA. Output devices may include a display device 62 and a speaker 63. The display device 62 may be a central display, multi-information display, head-up display, or navigation system display, such as one installed on the instrument panel. The speaker 63 may be a speaker for an audio system or navigation system.

[0032] [Software Composition]

[0033] Figure 2 This is a schematic diagram illustrating the software configuration of the ECU 10 according to this embodiment. Figure 2 As shown, the ECU 10 includes a lane recognition unit 100, an LDA control unit 110, an LTA control unit 120, and an LDA priority processing unit 130 as functional elements. These functional elements 100-130 are implemented by the CPU 11 of the ECU 10 reading a program stored in the ROM 12 into the RAM 13 and executing it. Furthermore, while each of the functional elements 100-130 is described as an integral part of the ECU 10 in this embodiment, any part thereof can also be provided in another ECU separate from the ECU 10. Additionally, all or part of the functional elements 100-130 of the ECU 10 can also be provided in an information processing device of a facility capable of communicating with the vehicle's VH (e.g., a management center).

[0034] The lane recognition unit 100 identifies the lane in which the vehicle is traveling (VH) based on the detection results of the external sensor device 40. Here, a lane refers not only to the white lines, yellow lines, and other dividing lines drawn on the road surface, but also to the driving area defined by structures such as curbs, guardrails, and walls. Furthermore, for convenience, the boundaries of the driving area defined by these dividing lines, structures, etc., will be referred to as "boundary lines" below.

[0035] like Figure 3 As shown, the lane recognition unit 100 recognizes the left boundary line LL and the right boundary line LR. Furthermore, the lane recognition unit 100 calculates the curvature radius R of the center line LC, which is the center position of these left and right boundary lines LL and LR, and calculates the deviation angle (hereinafter referred to as the yaw angle θy) between the direction of the center line LC and the direction in which the vehicle VH is facing. Further, the lane recognition unit 100 calculates the respective road width directions of distance (hereinafter referred to as the lateral position Δx) between the vehicle VH (e.g., the left front wheel) and the left boundary line LL, and between the vehicle VH (e.g., the right front wheel) and the right boundary line LR. Figure 3 Only the lateral position Δx between vehicle VH and the left boundary LL is shown. In this case, there are two lateral positions Δx, one on the left and one on the right. However, during LDA control described later, the lateral position Δx in the direction in which vehicle VH deviates from the lane, i.e., the direction indicated by the yaw angle θy, is used. Hereinafter, the lateral position Δx, yaw angle θy, and curve radius R calculated by the lane recognition unit 100 will be collectively referred to as "lane information".

[0036] When the vehicle VH is traveling at a speed exceeding a predetermined threshold speed Vv, if it deviates from or is about to deviate from its lane, the LDA control unit 110 issues an alarm and performs LDA control to prevent the vehicle VH from deviating from its lane by controlling the operation of the steering device 22. Hereinafter, the alarm issued by the LDA control unit 110 will be referred to as the "LDA lane departure alarm." Furthermore, the steering control performed by the LDA control unit 110 will be referred to as "LDA steering control."

[0037] When the vehicle speed V of vehicle VH is above the threshold speed Vv, the LDA control unit 110 determines whether the LDA steering start condition is met. For example, an LDA steering start condition could be defined as the predicted arrival time TR (or the lateral position Δx of vehicle VH) before vehicle VH reaches the boundary lines LL and LR (left boundary LL in the example) becoming the prescribed LDA steering threshold T. LDA＿1 In the following cases, the predicted arrival time TR can be calculated, for example, based on well-known formulas assuming that the vehicle VH undergoes uniformly accelerated linear motion before reaching the boundary lines LL and LR.

[0038] When the LDA steering start condition is met, the LDA control unit 110 calculates the target steering angle (hereinafter referred to as the LDA target steering angle σB) for LDA control based on the lane information (Δx, θY, R) obtained by the lane recognition unit 100. The LDA target steering angle σB is a steering angle set in a way that prevents the vehicle VH from deviating to the outside of the boundary lines LL, LR (left boundary LL in the example). The LDA control unit 110 calculates the LDA auxiliary torque Ts based on the steering angle difference Δσ between the LDA target steering angle σB and the actual steering angle σD obtained by the steering angle sensor 32. After calculating the LDA auxiliary torque Ts, the LDA control unit 110 sends a command signal containing information representing the LDA auxiliary torque Ts to the steering device 22. As a result, the LDA auxiliary torque Ts is transmitted from the steering motor 25 to the steering shaft 24, causing the steering wheels of the vehicle VH to steer.

[0039] Furthermore, when performing LDA steering control, the LDA control unit 110 determines whether the LDA alarm execution conditions are met. For example, an LDA alarm execution condition might be that the predicted arrival time TR (or the lateral position Δx of vehicle VH) before reaching the boundary lines LL and LR is greater than the LDA steering threshold T. LDA_1 Small specified LDA alarm threshold T LDA_2 The following situations apply. Additionally, the LDA alarm threshold T... LDA_2 It can also be related to the LDA steering threshold T. LDA_1The same value. When the LDA alarm execution conditions are met, the LDA control unit 110 executes the LDA deviation alarm. The LDA deviation alarm is activated, for example, by displaying a warning image on the display device 62, emitting a warning sound from the speaker 63, or applying vibration to the steering wheel SW.

[0040] After starting LDA control, when the lateral position Δx of vehicle VH obtained by lane recognition unit 100 becomes more than or equal to the predetermined lateral position Δx2 for termination determination, LDA control unit 110 considers that the lane deviation of vehicle VH has been eliminated (LDA termination condition is met) and terminates LDA control.

[0041] The LTA control unit 120 performs LTA (Lane Tapping Adjustment) to automatically change the steering angle (steering angle of the steering wheels) in a manner that keeps the center of gravity of the vehicle (VH) near the target driving line within the lane. LTA itself is well-known, and will therefore be described simply below. When the LTA start switch 61 is turned on, the LTA control unit 120 sets the target driving line of the vehicle (VH) based on the left and right boundary lines LL and LR identified by the lane recognition unit 100. The target driving line is, for example, set at the center of the left and right boundary lines LL and LR (center line LC). The LTA control unit 120 changes the steering angle of the vehicle (VH) by controlling the operation of the steering device 22 in a manner that keeps the center of gravity of the vehicle (VH) near the target driving line within the lane. Thus, the vehicle (VH) is kept within the driving lane.

[0042] When the vehicle VH deviates from or is about to deviate from the lane due to driver intervention or control limits during curve driving, the LTA control unit 120 issues an alert. Hereinafter, the alert issued by the LTA control unit 120 will be referred to as the "LTA Departure Alert". The LTA control unit 120 determines whether the LTA alert execution conditions are met during LTA control execution. For example, the predicted arrival time TR (or the lateral position Δx of the vehicle VH) before reaching the boundary lines LL and LR can be used as the predetermined LTA alert threshold T. LTA The following situations apply. LTA alarm threshold T LTA There are no specific limitations, for example, it is greater than the LDA steering threshold T mentioned above. LDA＿1 LDA alarm threshold T LDA＿2 Larger values. If the LTA alarm execution conditions are met, the LTA control unit 120 executes the LTA deviation alarm. The LTA deviation alarm is activated, for example, by emitting a warning sound from the speaker 63 or by displaying a warning image (such as a hand-off warning display urging steering wheel operation) on the display device 62.

[0043] Simultaneously, during the execution of LTA control, if the vehicle speed V of vehicle VH reaches or exceeds the threshold speed Vv, then LDA control also becomes effective. In existing devices, under such circumstances, if vehicle VH deviates from or is about to deviate from its lane, in addition to the LTA lane departure warning, an LDA lane departure warning will also be continuously generated.

[0044] Specifically, such as Figure 5 As shown, suppose that during LTA control and with LDA control active, the LTA alarm execution condition is met at time t1. In this case, an LTA lane departure warning (warning sound and warning display) is executed at time t1. Furthermore, immediately following at time t2, if the LDA steering start condition is met, LDA steering control is executed. In this case, due to the intervention of LDA steering control, LTA control ends, so the LTA lane departure warning at time t1 becomes an instantaneous warning. Further, at time t3, if the LDA alarm execution condition is met, an LDA lane departure warning (warning sound, warning display, and vibration) is executed. That is, the problem arises from the instantaneous LTA lane departure warning at time t1 and the subsequent identical LDA lane departure warning at time t3, which can be annoying to the driver.

[0045] The LDA priority processing unit 130 effectively suppresses driver frustration by preventing the continuous generation of both LTA and LDA deviation alarms. Specifically, during LTA control execution, the LDA priority processing unit 130 performs LDA priority processing in a manner that prioritizes LDA control over LTA deviation alarms, making LDA control easier to operate. LDA priority processing can be achieved, for example, by setting an LDA steering threshold T that enables LDA steering initiation conditions. LDA＿1 The LTA alarm threshold T is greater than the condition that triggers the LTA alarm. LTA This can be done, or it can be achieved by setting the LDA steering threshold T. LDA＿1 To match the LTA alarm threshold T LTA The same value can be used, or the LDA steering threshold T can be set. LDA＿1 This is done when LTA control is not being executed. Alternatively, LTA control can be prioritized by causing LTA to deviate from the alarm itself and stop.

[0046] Thus, by performing LDA priority processing during the execution of LTA control, for example, as Figure 4As shown, if vehicle VH is about to deviate from its lane at time t1, LDA steering control is initiated before the LTA lane departure warning is issued. That is, by intervening early with LDA steering control, LTA control is canceled, thereby suppressing the instantaneous generation of the LTA lane departure warning. As a result, even if the LDA lane departure warning is issued at time t2 due to the fulfillment of the LDA warning execution conditions, the consecutive generation of both lane departure warnings can be effectively prevented. Furthermore, by initiating LDA steering control at time t1, the stage before vehicle VH deviates from its lane, the likelihood of vehicle VH avoiding lane departure can be effectively increased.

[0047] Figure 6 This is a flowchart illustrating the routine of LDA priority processing performed by the CPU 11 of ECU 10. This routine begins, for example, by the movement of the vehicle VH.

[0048] In step S100, ECU 10 determines whether the LTA start switch 61 is turned on. If the LTA start switch 61 is turned on ("Yes"), ECU 10 proceeds to step S110. On the other hand, if the LTA start switch 61 is not turned on ("No"), that is, if the LTA start switch 61 is off, ECU 10 returns to the previous procedure.

[0049] In step S110, ECU 10 performs LTA control. Next, in step S120, ECU 10 determines whether the LTA alarm execution condition is met. If the LTA alarm execution condition is met ("Yes"), ECU 10 proceeds to step S130. On the other hand, if the LTA alarm execution condition is not met ("No"), ECU 10 returns to step S100.

[0050] In step S130, ECU 10 terminates LTA control and executes LDA control. Next, in step S140, ECU 10 determines whether the LDA steering start condition and the LDA alarm execution condition are met. If the LDA steering start condition and the LDA alarm execution condition are met ("Yes"), ECU 10 proceeds to step S145, executes LDA steering control and the LDA deviation alarm, and returns to step S140. Conversely, if the LDA steering start condition and the LDA alarm execution condition are not met ("No"), ECU 10 proceeds to step S150.

[0051] In step S150, ECU 10 determines whether the LDA termination condition is met. If the LDA termination condition is met ("Yes"), ECU 10 proceeds to step S160 and terminates LDA control. On the other hand, if the LDA termination condition is not met ("No"), ECU 10 returns to step S140.

[0052] In step S170, ECU 10 determines whether the LTA restart condition for restarting LTA control is met. Examples of LTA restart conditions include a decrease in the steering torque Tq detected by the steering torque sensor 33 to below a predetermined value (i.e., a situation where the driver's steering operation has converged to some extent, such as when the driver and LTA steering control overlap). If the LTA restart condition is met ("Yes"), ECU 10 proceeds to step S180. Conversely, if the LTA restart condition is not met ("No"), ECU 10 returns to step S170.

[0053] In step S180, ECU 10 restarts LTA control. Afterwards, ECU 10 returns to the previous routine.

[0054] The lane departure warning device, lane departure warning method and procedure involved in this embodiment have been described above. However, this disclosure is not limited to the above embodiment. Various modifications can be made as long as they do not deviate from the purpose of this disclosure.

[0055] For example, in the above embodiment, LDA priority processing is described as being performed by advancing the timing of LDA steering control actions. However, it can also be configured to advance the timing of LDA deviation warning actions in addition to advancing the timing of LDA steering control actions. Furthermore, the technology disclosed herein can also be applied to autonomous vehicles that perform some or all of their driving operations automatically.

Claims

1. A lane departure warning device that issues an alert when a vehicle deviates from or is about to deviate from its lane, the lane departure warning device comprising: The first alarm unit, during the execution of lane keeping control to keep the vehicle in the lane, determines whether there is a possibility that the vehicle may deviate from the lane, and implements a first deviation alarm when it determines that there is a possibility of deviation. The second warning unit determines, while the vehicle is in motion, whether there is a possibility that the vehicle may deviate from the lane, and when it is determined that there is a possibility of deviation, implements steering control to suppress the vehicle from deviating from the lane and a second deviation warning. as well as The priority processing unit performs priority processing during the execution of the lane keeping control, prioritizing the implementation of the steering control and / or the second departure warning by the second alarm unit over the implementation of the first departure warning by the first alarm unit.

2. The lane departure warning device according to claim 1, wherein, The priority processing is performed by advancing the timing of the steering control and / or the second deviation alarm implemented by the second alarm unit compared to the timing of the first deviation alarm implemented by the first alarm unit.

3. The lane departure warning device according to claim 1, wherein, If either the first alarm unit or the second alarm unit determines that there is a possibility that the vehicle may deviate from the lane, the priority processing is performed by stopping the first lane departure warning issued by the first alarm unit and causing the second alarm unit to implement the steering control and / or the second lane departure warning.

4. A lane departure warning method, which issues a warning when a vehicle deviates from or is about to deviate from its lane, wherein, During the execution of lane-keeping control to keep the vehicle within the lane, it is determined whether there is a possibility that the vehicle may deviate from the lane, and a first deviation warning is issued when it is determined that there is a possibility of deviation. While the vehicle is in motion, it is determined whether there is a possibility that the vehicle may deviate from the lane, and if it is determined that there is a possibility of deviation, steering control to prevent the vehicle from deviating from the lane and a second lane departure warning are implemented. During the execution of the lane keeping control, a priority process is performed that prioritizes the implementation of the steering control and / or the second lane departure warning over the implementation of the first lane departure warning.

5. A program that causes a computer of a lane departure warning device to execute a warning when a vehicle deviates from or is about to deviate from its lane: The first alarm processing involves determining, during the execution of lane keeping control to keep the vehicle within the lane, whether there is a possibility that the vehicle may deviate from the lane, and implementing a first deviation alarm when it is determined that there is a possibility of deviation. The second alarm process involves determining, while the vehicle is in motion, whether there is a possibility that the vehicle may deviate from the lane, and if it is determined that there is a possibility of deviation, implementing steering control to suppress the vehicle from deviating from the lane and a second deviation alarm. as well as Priority processing is performed during the execution of lane keeping control, such that the implementation of steering control and / or the second departure warning based on the second alarm takes precedence over the implementation of the first departure warning based on the first alarm.

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