Driving assistance device for vehicle

Abstract

A calculation device of a vehicle driving support device estimates the type of a road surface on the basis of an image obtained by capturing an image of the road surface in front of a host vehicle, compares the state of the host vehicle with a threshold value relating to the state of the host vehicle determined in accordance with the type of the road surface, and notifies a driver of the host vehicle of a proposal of a deceleration operation on the basis of the comparison result.

Description

Technical Field

[0001] This invention relates to a driving assistance device for vehicles. Background Technology

[0002] Previously, technologies for vehicle control based on road surface information were known. Patent Document 1 describes an automatic braking device that uses information such as the road surface friction coefficient detected by sensors to calculate the threshold for automatic braking.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 5-50901 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In the automatic braking device described in Patent Document 1, the time required for deceleration is longer when the road resistance is low, which leads to a problem that the duration of automatic braking is longer and the risk of collision increases.

[0008] The purpose of this invention is to provide a vehicle driving assistance device that can reduce the risk of collision accidents when driving on roads with low road resistance.

[0009] Methods for solving problems

[0010] One aspect of the present invention is a vehicle driving assistance device having a computing unit, wherein the computing unit estimates the type of the road surface based on an image obtained by photographing the road surface in front of the vehicle, compares the state of the vehicle with a threshold related to the state of the vehicle determined according to the type of the road surface, and notifies the driver of the vehicle of a proposal to decelerate based on the comparison result.

[0011] The effects of the invention

[0012] According to the present invention, the risk of collision accidents when driving on roads with low road resistance can be reduced. Attached Figure Description

[0013] Figure 1 This is a block diagram schematically illustrating the hardware configuration of the vehicle driving assistance device according to the first embodiment.

[0014] Figure 2 This is a block diagram schematically illustrating the functional configuration of the vehicle driving assistance device according to the first embodiment.

[0015] Figure 3 This is a flowchart of the vehicle control process.

[0016] Figure 4 This is a flowchart of AEB action processing.

[0017] Figure 5 This is a flowchart of FCW action processing.

[0018] Figure 6 This is a flowchart of the AEB target deceleration calculation process.

[0019] Figure 7 This is a diagram showing an example of a road surface resistance gauge.

[0020] Figure 8 This is a flowchart of the braking control process.

[0021] Figure 9 This is a flowchart of the instrument control process.

[0022] Figure 10 This is a flowchart of the vehicle speed selection process.

[0023] Figure 11 This is a flowchart of the deceleration proposal display process.

[0024] Figure 12 This is a flowchart showing the process of obtaining and processing the license determination result.

[0025] Figure 13 This is a flowchart for obtaining and processing the deceleration proposal determination result.

[0026] Figure 14 This is a diagram representing an example of a deceleration proposal threshold table.

[0027] Figure 15 This is a diagram illustrating an example of a deceleration proposal threshold table in the second embodiment.

[0028] Figure 16 This is a flowchart of the deceleration proposal determination result acquisition process in the third embodiment.

[0029] Figure 17 This is a flowchart of the deceleration proposal determination result acquisition process in the fourth embodiment.

[0030] Figure 18 This is a flowchart of the deceleration proposal determination result acquisition process in the fifth embodiment. Detailed Implementation

[0031] <First Implementation>

[0032] Reference Figures 1 to 14 The vehicle driving assistance device according to an embodiment of the present invention will be described.

[0033] Figure 1This is a block diagram schematically illustrating the hardware configuration of the vehicle driving assistance device according to the first embodiment. The vehicle 1 is equipped with a vehicle driving assistance device 2, a stereo camera 3, a braking control device 4, and an instrument control device 5. These devices are communicatively connected to each other via a communication path such as CAN (Controller Area Network). The vehicle 1 has a so-called anti-lock braking system (ABS).

[0034] The vehicle driving assistance device 2 is mounted on the vehicle 1, which is the object of control, and performs driving control such as automatic deceleration control of the vehicle 1, and provides information to the driver of the vehicle 1. In the following description, the vehicle 1, which is the object of control of the vehicle driving assistance device 2, is sometimes referred to as "this vehicle".

[0035] The stereo camera 3 consists, for example, of a pair of left and right cameras using a solid-state imaging element such as a charge-coupled device (CCD). The stereo camera 3 is mounted near the roof of the vehicle compartment to capture images of the road surface in front of the vehicle 1 and obstacles located in front of the vehicle 1. The stereo camera 3 outputs the captured image data (stereo image data) of the left and right pairs to the vehicle's driving assistance device 2.

[0036] Braking control device 4 is connected to vehicle driving assistance device 2. Based on braking control information sent from vehicle driving assistance device 2, braking control device 4 controls braking device 6 connected to it to decelerate vehicle 1. Braking device 6 is, for example, a disc brake or drum brake, and generates friction with the wheels of vehicle 1, thus decelerating vehicle 1.

[0037] The instrument control unit 5 is connected to the vehicle driving assistance device 2. A buzzer 7 and a display device 8 are connected to the instrument control unit 5. Based on the notification control information sent from the vehicle driving assistance device 2, the instrument control unit 5 notifies the driver by emitting a prescribed sound effect from the buzzer 7 or displaying a prescribed message or image on the display device 8.

[0038] The vehicle driver assistance device 2 is a device that avoids or mitigates collision damage by controlling the brakes, etc. The vehicle driver assistance device 2 implements automatic deceleration control, i.e., Automatic Emergency Braking (AEB), to automatically control braking to avoid or mitigate collisions between the vehicle 1 and obstacles. The vehicle driver assistance device 2 also implements a forward collision warning (FCW) function to warn the driver of the possibility of a collision between the vehicle 1 and an obstacle. In the AEB function, the vehicle driver assistance device 2 sequentially applies initial braking and main braking to the vehicle 1.

[0039] The vehicle driving assistance device 2 is composed of a computer, which includes a CPU (Central Processing Unit), MPU (Micro Processing Unit), DSP (Digital Signal Processor) and other computing units 11, non-volatile memory such as ROM (Read Only Memory), flash memory, and hard disk drive 12, volatile memory called RAM (Random Access Memory) 13, input / output interfaces 14, and other peripheral circuits. This hardware works together to enable software operation to achieve various functions. Furthermore, the vehicle driving assistance device 2 can be composed of one computer or multiple computers. Additionally, as the processing unit, ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), etc., can be used.

[0040] The non-volatile memory 12 stores programs capable of performing various operations. That is, the non-volatile memory 12 is a storage medium (storage device) capable of reading programs that implement the functions of this embodiment. The volatile memory 13 is a storage medium (storage device) that temporarily stores the operation results of the arithmetic unit 11 and signals input from the input / output interface 14. The arithmetic unit 11 is a device that unfolds the program stored in the non-volatile memory 12 in the volatile memory 13 and performs operations, performing prescribed arithmetic processing on data retrieved from the input / output interface 14, the non-volatile memory 12, and the volatile memory 13 according to the program.

[0041] The input section of the input / output interface 14 converts signals input from various devices (such as the stereo camera 3) into data that can be processed by the arithmetic unit 11. Furthermore, the output section of the input / output interface 14 generates an output signal corresponding to the processing result in the arithmetic unit 11 and outputs this signal to various devices (such as the brake control device 4 and the instrument control device 5).

[0042] When the ignition voltage of the vehicle 1 decreases, the vehicle driving assistance device 2 stops the operation of the computing unit 11, etc., and starts the computing unit 11, etc. again when the ignition voltage of the vehicle 1 returns to above the starting voltage threshold. Therefore, in the state of low ignition voltage, that is, when the engine is stopped, the control processing does not operate.

[0043] Figure 2 This is a block diagram schematically illustrating the functional configuration of the vehicle driving assistance device 2 according to the first embodiment. The vehicle driving assistance device 2 includes an input unit 21, a parallax acquisition unit 22, a relative position calculation unit 23, a relative speed calculation unit 24, an object detection unit 25, a road surface estimation unit 26, a fault detection unit 27, a function stop detection unit 28, a braking control unit 29, an instrument control unit 30, a deceleration suggestion unit 31, and an output unit 32.

[0044] Stereoscopic image data and other data are input to the input unit 21 from an external device such as a stereoscopic camera 3. The disparity acquisition unit 22 acquires disparity information based on the stereoscopic image data input to the input unit 21 from the stereoscopic camera 3. The relative position calculation unit 23 calculates the relative position and relative distance between the vehicle 1 and a stereoscopic object (obstacle) located in front of the vehicle 1 based on the disparity information acquired by the disparity acquisition unit 22. The relative speed calculation unit 24 differentiates the relative position calculated by the relative position calculation unit 23 based on the elapsed time, thereby calculating the relative speed between the vehicle 1 and the obstacle. The object detection unit 25 detects obstacles in the image data using image data from either the left or right side. The object detection unit 25 classifies the detected obstacles into categories such as pedestrians, bicycles, vehicles, and other stopped obstacles. The detection and classification of obstacles can utilize known techniques such as pattern matching and machine learning. For example, the object detection unit 25 detects in the image data that a three-dimensional object of a certain size or larger (e.g., the area where a child or pedestrian is hidden) exists on the vehicle 1's travel path or within a certain distance (e.g., 10m to the left or right) from the vehicle 1's travel path. Here, the object detection unit 25 investigates whether a parallax of a certain size or larger exists on the vehicle 1's travel path or within a certain distance to the left or right of the vehicle 1's travel path based on the parallax information acquired by the parallax acquisition unit 22. If it exists, it determines that an obstacle exists ahead. The road surface estimation unit 26 acquires information about the color and brightness of the road on which the vehicle 1 is traveling based on image data from either the left or right side. Using this acquired information, the road surface estimation unit 26 estimates the type of road surface ahead of the vehicle 1. For example, the road surface estimation unit 26 classifies the road surface into categories such as dry paved road, wet paved road, dirt road, gravel road, and icy road.

[0045] The fault detection unit 27 performs the fault detection processing described later, detecting faults occurring in the vehicle driving assistance device 2, etc. The function stop detection unit 28 performs the function stop detection processing described later, detecting function stops occurring in the vehicle driving assistance device 2, etc. The brake control unit 29 generates data related to brake control. The instrument control unit 30 generates data related to instrument control. The deceleration suggestion unit 31 notifies the driver of vehicle 1 of a deceleration operation suggestion (hereinafter also referred to as a deceleration suggestion). The output unit 32 converts the data generated by the brake control unit 29 and the instrument control unit 30 into communication data, and outputs the communication data to the brake control device 4 and the instrument control device 5.

[0046] Figure 3 This is a flowchart of the vehicle control processing. The computing unit 11 of the vehicle driving assistance device 2 executes repeatedly at short intervals (e.g., every 50 milliseconds). Figure 3The vehicle control process is shown. Therefore, it is possible to perform corresponding vehicle control based on the constantly changing surrounding environment of vehicle 1, the movement status of vehicle 1, and the driving operations performed on vehicle 1.

[0047] In step S100, the input unit 21 receives stereoscopic image data from the stereoscopic camera 3. In step S110, the disparity acquisition unit 22 acquires disparity data from the stereoscopic image data received in step S100. In step S120, the relative position calculation unit 23 uses the disparity information acquired in step S110 to calculate the relative position and relative distance between the vehicle 1 and the obstacle. In step S130, the relative speed calculation unit 24 uses the relative position calculated in step S120 to calculate the relative speed between the vehicle 1 and the obstacle. In step S140, the object detection unit 25 uses the image data acquired in step S100 and the disparity information acquired in step S110, etc., to detect and classify obstacles mapped into the image data. In step S150, the road surface estimation unit 26 uses the image data acquired in step S100 and the disparity information acquired in step S110, etc., to estimate the road surface category of the road surface on which the vehicle 1 is traveling.

[0048] In step S160, the fault detection unit 27 performs fault detection processing. Fault detection processing detects whether the vehicle 1 has experienced a fault such that the processing performed by the vehicle driving assistance device 2 cannot be performed normally. The fault detection processing includes processing for detecting internal faults of the vehicle driving assistance device 2 and processing for detecting external faults of the vehicle driving assistance device 2 (e.g., faults in components connected to the vehicle driving assistance device 2).

[0049] In troubleshooting the internal faults of the vehicle driving assistance device 2, the voltage value of the power supply circuit of the vehicle driving assistance device 2 and the value of the temperature sensor provided with the vehicle driving assistance device 2 are monitored to detect deviations from the normal range. Additionally, by monitoring whether the value of the volatile memory 13, which temporarily holds the calculation results of each control process, has changed, it is confirmed that the calculation results of the control processes are performed as programmed. If it is determined that the calculation results of the control processes are not performed as programmed, an internal fault is considered to exist.

[0050] In the process of detecting external faults in the vehicle driver assistance device 2, for example, based on information received via CAN, the system detects situations where the information required for the correct execution of the vehicle driver assistance device 2 cannot be obtained. Examples include whether the circuit for detecting brake pedal operation is fixed or disconnected, preventing the driver's operation from being determined; whether the communication path for transmitting information from the wheel speed sensors to the vehicle driver assistance device 2 is disconnected, preventing the determination of the vehicle 1's movement status; or whether the stereo camera 3's shooting range is significantly deviated in one of the left or right directions, preventing the correct identification of the front of the vehicle 1. If a situation is determined where the information required for the correct execution of the vehicle driver assistance device 2 cannot be obtained, an external fault is considered to exist.

[0051] In the event of a malfunction, the driver is notified that a malfunction has been detected. Furthermore, it is preferable to store information useful for malfunction repair in the vehicle driving assistance device 2, which can be read during repairs to easily determine the repair location.

[0052] By constructing a fault detection process as described above, the system continuously monitors whether the vehicle driving assistance device 2 can be properly executed, preventing accidental miscontrol of the vehicle 1 and enabling rapid repair even if a fault occurs.

[0053] In step S170, the function stop detection unit 28 performs function stop detection processing. Similar to the fault detection processing, the function stop detection processing includes the following steps: determining whether the state of correctly executing the processing of the vehicle driving assistance device 2 can be maintained by monitoring the internal state of the vehicle driving assistance device 2, and determining whether the state of correctly executing the processing of the vehicle driving assistance device 2 can be maintained based on the external state of the vehicle driving assistance device 2.

[0054] Regarding internal status monitoring, for example, the voltage value of the power supply circuit of the vehicle driving assistance device 2 is monitored to determine whether the supply voltage is stable. Regarding the stability of the supply voltage, the time required for the charge of each component constituting the vehicle driving assistance device 2 to stabilize after the engine is turned on is determined, and it is determined whether sufficient time has elapsed after the voltage value reaches a certain level. In addition to the voltage value, the values ​​of temperature sensors and other sensors installed in the vehicle driving assistance device 2 are also monitored to ensure that normal operation of the vehicle driving assistance device 2 can continue. If it is determined that normal operation of the vehicle driving assistance device 2 cannot continue, the function is stopped due to an internal cause.

[0055] Regarding external status monitoring, for example, based on information obtained from the stereo camera 3, it is determined that the vehicle speed sensor information cannot be read immediately after the engine is turned on, or that the stereo camera 3's image cannot correctly identify the external environment of the vehicle 1 due to lens contamination or obstruction by inclement weather. If it is determined that the system is trapped in any of the following situations—inability to correctly detect the external environment of the vehicle 1, the vehicle 1's movement status, or its operational status—and the normal operation of the vehicle driver assistance device 2 cannot continue, it is considered a function stoppage due to an external cause. Furthermore, in the case of a function stoppage due to either an internal or external cause, it is considered a function stoppage related to the vehicle driver assistance device 2. In the event of a function stoppage, the driver is notified of the function stoppage.

[0056] By configuring the function stop detection process as described above, it is possible to continuously monitor whether the vehicle driving assistance device 2 can be correctly executed, thus preventing accidental miscontrol of the vehicle 1 and preventing the driver from over-relying on the vehicle driving assistance device 2 and neglecting deceleration operations.

[0057] In step S180, the brake control unit 29 performs the AEB (Autonomous Emergency Braking) operation processing described later. In step S190, the brake control unit 29 performs the FCW (Forward Collision Warning) operation processing described later. In step S200, the brake control unit 29 performs the AEB target deceleration calculation processing described later. In step S210, the brake control unit 29 performs the brake control processing described later. In step S220, the instrument control unit 30 performs the instrument control processing described later. In step S230, the deceleration suggestion unit 31 performs the vehicle speed selection processing described later. In step S240, the deceleration suggestion unit 31 performs the deceleration suggestion display processing described later.

[0058] In step S250, the output unit 32 performs data output processing. In this data output processing, based on the processing results of steps S100 to S240, data is converted for communication and transmitted to the braking control device 4 and the instrument control device 5. The conversion of the communication data involves converting the braking control indication, AEB target deceleration, warning display, AEB / FCW buzzer action indication, deceleration suggestion display, and deceleration suggestion buzzer action indication calculated and determined in each process according to the specifications of the communication path. For example, the AEB target deceleration calculated in floating-point format is converted to a 16-bit integer value. Furthermore, status signals such as braking control indications are assigned values ​​and converted to digital values ​​for communication, such as 0 for deactivation and 1 for activation (ABS disabled). Moreover, to avoid noise on the communication path, such as to prevent the erroneous transmission of excessively large emergency braking decelerations during communication, error detection symbols such as cyclic redundancy check (CRC), parity bits, and checksums are assigned to each data as communication data. Then, the brake control indication and AEB target deceleration, which are converted into communication signals, are sent to the brake control unit 4. The warning display, AEB / FCW buzzer action indication, deceleration proposal display, and deceleration proposal buzzer action indication are sent to the instrument control unit 5. This enables the reduction and avoidance of collision damage through the braking control of the vehicle 1, the reduction of collision damage and improvement of avoidance performance through notification to the driver, and the improvement of safety through the proposal to reduce the driving speed.

[0059] At this time, the buzzer 7 is controlled by the instrument control unit 5 to notify the driver. However, the buzzer 7 that sounds based on the AEB / FCW buzzer action indication has a larger volume, a longer sound duration, a higher pitch, or a combination of these features compared to the buzzer indicating a deceleration suggestion. This provides the driver with a greater sense of urgency. Furthermore, when the display device 8 is controlled by the instrument control unit 5 to notify the driver, the AEB or FCW warning display has a larger display area, brighter display, or uses a warning color such as red or yellow, or a combination of these features compared to the deceleration suggestion display. This further enhances the driver's sense of urgency. Conversely, the deceleration suggestion display provides a relatively smaller sense of urgency, and its prolonged display reduces driver inconvenience.

[0060] Figure 4 This is a flowchart of AEB action processing. AEB action processing starts from... Figure 3The process called in step S180. In step S300, the braking control unit 29 determines whether to permit AEB control. In this embodiment, the braking control unit 29 determines that AEB control is permitted if none of the following conditions are met. In other words, the braking control unit 29 determines that AEB control is not permitted if at least one of the following conditions is met.

[0061] (1) Fault detection and handling Figure 3 The result of step S160) is that a fault is detected.

[0062] (2) Function stop detection and processing ( Figure 3 The result of step S170) is that the function is detected to have stopped.

[0063] (3) Vehicle 1 stops.

[0064] (4) The speed of vehicle 1 exceeds the speed limit of AEB action.

[0065] (5) The gear position of vehicle 1 is reverse or parking.

[0066] (6) The driver’s rapid acceleration operation was detected.

[0067] (7) The driver’s sudden steering operation was detected.

[0068] (8) The driver’s steering input is above the prescribed amount.

[0069] (9) The absolute value of the yaw rate of vehicle 1 is above the specified amount.

[0070] (10) The stabilization control provided by the anti-skid device is in operation.

[0071] (11) The object detection unit 25 classifies objects into those that have little impact on the vehicle 1 even if it collides with the detected obstacle (e.g., grass).

[0072] (12) The obstacle detected by the object detection unit 25 does not exist on the travel path of the vehicle 1.

[0073] If any of the above conditions are met, the driver is likely to perceive the AEB as a malfunction when it activates. Therefore, in this embodiment, if any of the above conditions are met in step S300, the process proceeds to step S380. In step S380, the brake control unit 29 sets the AEB control to inactive, and the process ends. Figure 4 The AEB action processing is shown. On the other hand, if none of the above conditions are met in step S300, the processing proceeds to step S310.

[0074] In step S310, the braking control unit 29 acquires the collision probability judgment distance. The collision probability judgment distance is a threshold for determining whether to activate AEB. The braking control unit 29 acquires the collision probability judgment distance using the normal braking avoidance limit distance and the normal steering avoidance limit distance. The normal braking avoidance limit distance represents the limit of distance that can be avoided by the driver's normal braking operation, and is calculated by the following formula (1).

[0075] Normal braking avoidance limit distance [m] = (0.0167 × relative speed [km / h] + 1.00) × relative speed [m / s] … (1)

[0076] Here, relative speed refers to the relative speed between vehicle 1 and obstacle calculated by relative speed calculation unit 24.

[0077] The normal steering avoidance limit distance represents the limit of distance that a collision can be avoided by the driver's normal steering operation, and is calculated by the following formula (2).

[0078] The typical steering avoidance limit distance [m] = (0.0067 × overlap rate + 1.13) × relative speed [m / s]... (2)

[0079] Here, relative speed refers to the relative speed between vehicle 1 and the obstacle calculated by the relative speed calculation unit 24. In addition, the overlap rate represents the proportion of the obstacle on the travel path of vehicle 1, and is calculated based on the lateral position and lateral width of the obstacle, the width of vehicle 1, and the steering condition.

[0080] The braking control unit 29 compares the normal braking avoidance limit distance calculated by equation (1) above with the normal steering avoidance limit distance calculated by equation (2) above, and uses the shorter distance as the collision probability judgment distance. By setting the collision probability judgment distance in this way, AEB will only activate when the driver feels that a physical collision with an obstacle is unavoidable, and the driver will not over-rely on AEB. In addition, in step S310, if the AEB control processed in the previous cycle (the previous step S310) is the main braking, it is preferable to add a predetermined offset value to the collision probability judgment distance. As a result, even if the main braking is initiated due to noise or error in the detection result, AEB will not be immediately deactivated.

[0081] In step S320, the braking control unit 29 compares the relative distance between the vehicle 1 and the obstacle ahead, calculated by the relative position calculation unit 23, with the collision probability judgment distance obtained in step S310. If the relative distance is shorter than the collision probability judgment distance, the process proceeds to step S330. In step S330, the braking control unit 29 sets the AEB control to primary braking and ends the process. Figure 4The AEB (Autonomous Emergency Braking) operation is shown. On the other hand, if the relative distance in step S320 is not shorter than the collision probability judgment distance, the process proceeds to step S340. In step S340, the braking control unit 29 acquires the pre-braking judgment distance. Similar to the collision probability judgment distance, the pre-braking judgment distance is calculated based on the relative speed between the vehicle 1 and the obstacle calculated by the relative speed calculation unit 24 and the aforementioned overlap rate. Furthermore, the pre-braking judgment distance is set to a distance longer than the collision probability judgment distance.

[0082] The pre-braking determination distance has the following effects: it warns the driver of the deceleration of vehicle 1 and reduces the delay until the main braking force of AEB is applied, while increasing the deceleration amount; therefore, it is desirable to set a longer distance. On the other hand, if the pre-braking determination distance is too long, the driver may over-rely on AEB. Furthermore, if prolonged braking control is performed, the actual positional relationship between vehicle 1 and obstacles may differ from the initial prediction. Therefore, the pre-braking determination distance is adjusted according to the vehicle 1's characteristics and the capability of the braking device 6. Additionally, in step S340, if the AEB control processed in the previous cycle (previous step S340) is either main braking or pre-braking, it is preferable to add a predetermined offset value to the pre-braking determination distance. Thus, even if main braking is initiated due to noise or error in the detection result, AEB will not immediately disengage.

[0083] In step S350, the braking control unit 29 compares the relative distance between the vehicle 1 and the obstacle ahead, calculated by the relative position calculation unit 23, with the pre-braking determination distance obtained in step S340. If the relative distance is shorter than the pre-braking determination distance, the process proceeds to step S360. In step S360, the braking control unit 29 sets the AEB control to pre-braking and ends the process. Figure 4 The AEB (Automatic Emergency Braking) operation process is shown. On the other hand, if the relative distance in step S350 is not shorter than the pre-braking determination distance, the process proceeds to step S370. In step S370, the braking control unit 29 sets the AEB control to inactive, and the process ends. Figure 4 The AEB action processing is shown.

[0084] Figure 5 This is a flowchart of FCW action processing. FCW action processing starts from... Figure 3 The process called in step S190. In step S400, the braking control unit 29 determines whether to permit FCW control. In this embodiment, the braking control unit 29 determines that FCW control is permitted if none of the following conditions are met. In other words, the braking control unit 29 determines that FCW control is not permitted if at least one of the following conditions is met.

[0085] (1) Fault detection and handling Figure 3 The result of step S160) is that a fault is detected.

[0086] (2) Function stop detection and processing ( Figure 3 The result of step S170) is that the function is detected to have stopped.

[0087] (3) Vehicle 1 stops.

[0088] (4) The speed of vehicle 1 exceeds the FCW action limit speed.

[0089] (5) The gear position of vehicle 1 is reverse or parking.

[0090] (6) The driver’s rapid acceleration operation was detected.

[0091] (7) The driver’s sudden steering operation was detected.

[0092] (8) The driver’s steering input is above the prescribed amount.

[0093] (9) The absolute value of the yaw rate of vehicle 1 is above the specified amount.

[0094] (10) The stabilization control provided by the anti-skid device is in operation.

[0095] (11) The object detection unit 25 classifies objects into those that have little impact on the vehicle 1 even if it collides with the detected obstacle (e.g., grass).

[0096] (12) The obstacle detected by the object detection unit 25 does not exist on the travel path of the vehicle 1.

[0097] If any of the above conditions are met, the driver is likely to perceive the FCW as a malfunction when it activates. Therefore, in this embodiment, if any of the above conditions are met in step S400, the process proceeds to step S450. In step S450, the brake control unit 29 sets the FCW control to inactive, and the process ends. Figure 5 The FCW action processing is shown. On the other hand, if none of the above conditions are met in step S400, the processing proceeds to step S410.

[0098] In step S410, the braking control unit 29 acquires the FCW (Forward Collision Warning) action distance. Similar to the collision probability assessment distance and the pre-braking assessment distance, the FCW action distance is calculated based on the relative speed and overlap ratio between the vehicle 1 and the obstacle. Furthermore, the FCW action distance is set to be a distance longer than the pre-braking assessment distance.

[0099] The FCW (Forward Collision Warning) action distance is set so that the driver can avoid a collision by braking in response to the warning. For example, based on the characteristics of a typical driver of vehicle 1, the following are calculated: the unloaded distance traveled from the warning action to the application of the brake pedal; the braking distance traveled at a deceleration (e.g., 2.5 m / ss to 4 m / ss) without excessive pitch due to brake pedal operation until the relative speed between the obstacle and vehicle 1 is zero; and the distance after deceleration ends when the relative speed is zero (e.g., 0.2 to 0.9 m). The sum of these three distances is then set as the FCW action distance. Furthermore, in cases of reduced overlap, there is a risk of over-action due to steering of vehicle 1 or lateral movement of the obstacle relative to the vehicle; therefore, it is preferable to adjust the FCW action distance to be shorter.

[0100] In step S420, the braking control unit 29 compares the relative distance between the vehicle 1 and the obstacle ahead, calculated by the relative position calculation unit 23, with the FCW (Forward Collision Warning) action distance obtained in step S410. If the relative distance is shorter than the FCW action distance, the process proceeds to step S430. In step S430, the braking control unit 29 sets the FCW control to action and ends the process. Figure 5 The FCW (Forward Collision Warning) operation is shown. On the other hand, if the relative distance in step S420 is not shorter than the FCW operation distance, the process proceeds to step S440. In step S440, the braking control unit 29 sets the FCW control to inactive, and the process ends. Figure 5 The FCW action processing is shown.

[0101] By configuring FCW action processing as described above, false alarms can be suppressed, and the driver can be warned at appropriate times. The opportunity for the driver to perform braking operations can be set before the automatic braking action performed by AEB control occurs, enabling the driver to strive for safe driving.

[0102] Figure 6 This is a flowchart of the AEB target deceleration calculation process. The AEB target deceleration calculation process starts from... Figure 3 The processing of step S200 is called. In step S500, the braking control unit 29 determines that... Figure 4 The AEB action processing is configured to determine whether AEB control is the primary braking mechanism. If AEB control is the primary braking mechanism, the process proceeds to step S510. In step S510, the braking control unit 29 sets the deceleration during primary AEB braking to the target AEB deceleration and ends the process. Figure 6 The braking control unit 29 uses the following formula (3) to calculate the initial value of the deceleration during AEB main braking.

[0103] AEB target deceleration initial value = relative velocity2 / (2×(relative distance-0.5))…(3)

[0104] Here, relative speed refers to the relative speed between vehicle 1 and obstacle calculated by relative speed calculation unit 24, and relative distance refers to the relative distance between vehicle 1 and obstacle in front calculated by relative position calculation unit 23.

[0105] The braking control unit 29 performs various corrections on the initial value calculated by the above formula (3) to obtain the final AEB target deceleration. For example, it adds a distance corresponding to the control delay time after the braking unit receives the action start signal, or it corrects the value by using a specified lower limit of the main braking deceleration (e.g., 6 m / ss) to limit the lower limit of the AEB target deceleration so that it does not become too slow and becomes a deceleration that can definitely bring a sense of crisis to the driver.

[0106] On the other hand, if the AEB control is not the main braking mechanism in step S500, the process proceeds to step S520. In step S520, the braking control unit 29 determines that... Figure 4 The AEB control set in the AEB action processing is determined to be in the pre-braking state. If the AEB control is in the pre-braking state, the processing proceeds to step S530. In step S530, the braking control unit 29 obtains the road surface category estimated by the road surface estimation unit 26. In step S540, the braking control unit 29 uses the road surface category obtained in step S530 to obtain the deceleration limit value.

[0107] Figure 7 This is a diagram illustrating an example of a road surface resistance gauge. Pre-stored in non-volatile memory 12... Figure 7 The road resistance table 50 is shown. The road resistance table 50 stores the road resistance value corresponding to each road surface category. The braking control unit 29, through... Figure 7 The road resistance is obtained by referring to the road type obtained in step S530 in the road resistance table 50, and the road resistance corresponding to the road type is obtained. The braking control unit 29 processes the obtained road resistance value as a deceleration limit value. Here, since the unit of road resistance is G and the unit of deceleration limit value is m / ss, the braking control unit 29 multiplies the road resistance value by a predetermined coefficient to change the unit. Alternatively, the value after pre-changing the unit can be stored in the road resistance table 50.

[0108] in addition, Figure 7The contents of the road resistance table 50 shown are one example, and the contents of the road resistance table 50 can also be different. For example, for the case of road surface type soil, road resistance values ​​can be prepared separately for dry and wet conditions. Alternatively, the road surface type can be simplified to two types: paved road and dirt road, treating gravel roads and dirt roads as the latter, and all other road surfaces as the former. This is based on the following idea: if it is a paved road, the deceleration required for AEB, i.e., a deceleration of 6 m / ss or more, can be expected in both dry and wet conditions, so there is no need to distinguish between them. In addition, in the case of snow-covered or icy road surfaces, even the driver's normal braking operation will be hindered by insufficient road resistance, such as stopping actions. Therefore, if deceleration control itself is initiated, the stability control will act immediately. At this time, because in Figure 4 In step S300, AEB control is suppressed, so it can be considered unnecessary to consider whether the road surface is covered with snow or ice.

[0109] In step S550, the braking control unit 29 compares the deceleration limit value obtained in step S540 with the predetermined lower limit value of the main braking deceleration. If the deceleration limit value is greater than the lower limit value of the main braking deceleration, the process proceeds to step S560. In this case, even after the AEB control switches from pre-braking to main braking, the likelihood of achieving the desired deceleration performance is high. Therefore, in step S560, the braking control unit 29 calculates the deceleration during pre-braking and sets it as the AEB target deceleration, then ends the process. Figure 6 The braking control unit 29 calculates the deceleration during pre-braking based on the relative distance between the vehicle 1 and the obstacle in front calculated by the relative position calculation unit 23, and the relative speed between the vehicle 1 and the obstacle calculated by the relative speed calculation unit 24.

[0110] Specifically, based on the relative distance and relative speed at the start of pre-braking, the deceleration is set to be stronger as the relative distance decreases, or stronger as the relative speed of vehicle 1 approaches the obstacle more closely. Furthermore, the deceleration calculated here for pre-braking is preferably a weak deceleration that does not lead to excessive trust in the AEB by the driver, and a deceleration to which the driver can feel the deceleration caused by the braking action.

[0111] The deceleration calculated at the start of pre-braking is maintained until AEB control becomes the main brake or the pre-braking is released due to reasons such as avoiding obstacles. The increase in deceleration does not give the driver much sense of security. In addition, if noise is generated in the relative distance or relative speed information, or if the deceleration is weaker than expected due to the temperature of the braking unit, it is preferable that the brake control unit 29 recalculates the deceleration at the start of pre-braking.

[0112] The braking control unit 29 corrects the calculated deceleration during pre-braking by limiting it to an upper limit value of a predetermined pre-braking deceleration (e.g., 4 m / ss), so that a strong deceleration that would cause the driver to overestimate it will not occur during pre-braking.

[0113] On the other hand, if the deceleration limit value in step S550 is not greater than the lower limit of the main braking deceleration, the process proceeds to step S570. In this case, even if AEB control is switched to main braking, the vehicle 1 cannot be expected to achieve the desired deceleration as it continues to approach the obstacle. That is, even if strong deceleration braking control is performed along with main braking, the road surface and tire grip cannot be maintained, and the desired deceleration cannot be achieved, thus the effect of avoiding or mitigating collision damage is insufficient. Therefore, in step S570, the braking control unit 29 sets a predetermined upper limit value for the preparatory braking deceleration for the AEB target deceleration and ends the process. Figure 6 The processing.

[0114] The upper limit of the pre-braking deceleration is set to a value that prevents the driver from overestimating the deceleration of the AEB. Here, setting the upper limit of the pre-braking deceleration is intended to improve the AEB's effectiveness in reducing the collision speed by supplementing the insufficient deceleration during the main braking phase. For example, in step S550, although it is possible to consider starting the pre-braking action earlier based on road conditions, this action is not taken; instead, the setting of the upper limit of the pre-braking deceleration is maintained. This helps to suppress the increased risk of false braking caused by starting braking control from a distance and the driver's over-reliance on the AEB due to early AEB activation.

[0115] If the AEB control is not in the pre-braking state in step S520, the process proceeds to step S580. In step S580, the braking control unit 29 sets the AEB target deceleration to zero (0 [m / ss]) and ends the process. Figure 6 The processing involves steps S520. In step S520, "AEB control not preparing for braking" refers to a scenario where braking control by AEB is not required. Therefore, the value indicating that braking control by AEB will not be performed is set to the AEB target deceleration. Alternatively, a value other than zero can be set as the value indicating that braking control will not be performed. For example, a sufficiently large negative value (representing acceleration) can be set. Furthermore, a flag indicating that braking control will not be performed can be set separately from the AEB target deceleration.

[0116] By constructing the AEB target deceleration calculation process as described above, it is possible to suppress the driver's excessive reliance on AEB and to calculate and update the braking control quantity of AEB in order to maximize the effectiveness of avoiding and mitigating collision damage.

[0117] Figure 8 This is a flowchart of the braking control process. The braking control process starts from... Figure 3 The processing called in step S210. In step S600, the braking control unit 29 determines that... Figure 6 The process checks whether the AEB target deceleration set in the process is a value that indicates the execution of braking control (e.g., a value greater than zero). If the AEB target deceleration becomes a value greater than zero, the process proceeds to step S610.

[0118] In step S610, the brake control unit 29 acquires the road surface category estimated by the road surface estimation unit 26. In step S620, the brake control unit 29 determines whether the road surface category acquired in step S610 is a gravel road surface. If the road surface category is a gravel road surface, the process proceeds to step S630. In step S630, the brake control unit 29 sets the brake control instruction (disables ABS) and ends the process. Figure 8 The processing involves a gravel road surface, meaning the road ahead of vehicle 1 is composed of gravel. Generally, on gravel roads, the braking distance is shorter when ABS is not activated (because the tires get stuck in the gravel). Therefore, in step S630, a braking control instruction is set to disable ABS while performing braking control.

[0119] On the other hand, if the road surface type is not gravel in step S620, the process proceeds to step S640. In step S640, the brake control unit 29 sets the brake control instruction (enables ABS), and the process ends. Figure 8 The handling of this issue. On surfaces other than gravel roads, if the ABS does not activate when slippage occurs, the grip between the road surface and the tires is lost, and evasive maneuvers cannot be performed by steering. Therefore, the ABS is not disabled in step S640.

[0120] In step S600, if the AEB target deceleration does not reach a value greater than zero, the process proceeds to step S650. In this case, since braking control is considered unnecessary, in step S650, the braking control unit 29 deactivates the braking control instruction setting, and the process ends. Figure 8 The processing.

[0121] In addition, when monitoring the road surface grip condition, if the ABS is configured to release the braking pressure when it is assumed to be a gravel road surface, steps S610 to S630 can be omitted.

[0122] Figure 9 This is a flowchart of the instrument control process. The instrument control process starts from... Figure 3 The processing of step S220 is called. In step S700, the instrument control unit 30 determines that... Figure 4 The process involves determining whether the AEB control is set as the primary braking mechanism. If the AEB control is set as the primary braking mechanism, the process proceeds to step S710. In step S710, the instrument control unit 30 sets the warning display to a request. In the next step S715, the instrument control unit 30 sets the buzzer operation indicator to a continuous tone, and the process ends. Figure 9 The processing.

[0123] On the other hand, if the AEB control is not set to primary braking in step S700, the process proceeds to step S720. In step S720, the instrument control unit 30 determines whether the AEB control is for pre-braking. If the AEB control is set to pre-braking, the process proceeds to step S730. In step S730, the instrument control unit 30 sets the warning display to request. In the next step S735, the instrument control unit 30 sets the buzzer operation indicator to intermittent tone, and the process ends. Figure 9 The processing.

[0124] If the AEB control is not set to pre-braking in step S720, the process proceeds to step S740. In step S740, the instrument control unit 30 determines that... Figure 5 The process checks whether the FCW control is set to active. If the FCW control is set to active, the process proceeds to step S750. In step S750, the instrument control unit 30 sets the warning display to request. In the next step S755, the instrument control unit 30 sets the buzzer operation indicator to intermittent tone and ends the process. Figure 9 The processing.

[0125] If the FCW control is not set to operate in step S740, the process proceeds to step S760. In step S760, the instrument control unit 30 sets the warning display to stop. In the next step S765, the instrument control unit 30 sets the buzzer operation indicator to stop, and the process ends. Figure 9 The processing.

[0126] By configuring the instrument control process as described above, the priority of control states, determined in the order of AEB control (main braking), pre-braking, and FCW control, is set from high to low. That is, the control state that is set to notify the driver of the highest level of danger is selected, and higher priority control states are set to provide stronger warnings to the driver. Furthermore, in... Figure 9 In the example, a difference between continuous and intermittent tones was set in the buzzer sound, but if the volume and pitch were set differently before the control state, the current state could be communicated to the driver more effectively.

[0127] Figure 10 This is a flowchart of the vehicle speed selection process. The vehicle speed selection process starts from... Figure 3 The process called in step S230. In step S800, the deceleration suggestion unit 31 determines whether the ACC / CC acceleration control is in the set speed driving state. ACC / CC acceleration control refers to the control state of the adaptive cruise control (ACC) function or the cruise control (CC) function. That is, it means that the driver sets the driving speed of the vehicle 1 by operating a switch, and even if the accelerator pedal is not operated, the engine control unit or vehicle control device controls the engine or transmission, thereby maintaining the driving at the set speed.

[0128] If, in step S800, the ACC / CC acceleration control is set to a set speed while driving, the process proceeds to step S810. In this case, it indicates that vehicle 1 is driving at the speed set by the driver using the ACC or CC function, without any operation to adjust the vehicle speed via the accelerator pedal or any speed control based on the vehicle in front of vehicle 1. In step S810, the deceleration suggestion unit 31 sets the ACC / CC set speed and ends the process. Figure 10 The processing proceeds to step S820 if, in step S800, the ACC / CC acceleration control is not set at the set speed. In step S820, the deceleration suggestion unit 31 sets the wheel speed sensor values ​​to the vehicle speed, and the process ends. Figure 10 The processing.

[0129] When controlling speed using ACC or CC functions, a difference may arise between the set speed (the speed the driver desires) and the wheel speed immediately after the driver changes the set speed or switches between having and not having control. By configuring the speed selection process as described above, unwanted deceleration suggestions can be suppressed, and delays in deceleration suggestions can be prevented. Furthermore, by targeting only the ACC or CC functions, situations such as making deceleration suggestions while using the accelerator pedal for speed control, or making excessive deceleration suggestions when the ACC or CC function's set speed is high but the vehicle can travel at an appropriate speed according to the speed of the vehicle in front, can be prevented.

[0130] Figure 11 This is a flowchart of the deceleration proposal display process. The deceleration proposal display process starts from... Figure 3 The process called in step S240. In step S900, the deceleration proposal unit 31 performs the display permission determination result acquisition process described later. The display permission determination result acquisition process sets the display permission determination to be permitted or prohibited. In step S910, the deceleration proposal unit 31 determines whether the processing result of step S900 indicates that the display permission determination has been set to permitted. If the display permission determination has not been set to permitted, the process proceeds to step S960. In step S960, the deceleration proposal unit 31 sets the deceleration proposal display to stop, and the process proceeds to step S970.

[0131] On the other hand, if the permission determination is set to permission in step S910, the process proceeds to step S920. In step S920, the deceleration proposal unit 31 performs the deceleration proposal determination result acquisition process described later. Based on the deceleration proposal determination result acquisition process, the deceleration proposal is set to display or stop. In step S930, the deceleration proposal unit 31 determines whether the processing result of step S920 indicates that the deceleration proposal is set to display. If the deceleration proposal is set to display, the process proceeds to step S940. In step S940, the deceleration proposal unit 31 sets the deceleration proposal display to request, and the process proceeds to step S970. On the other hand, if the deceleration proposal is not set to display in step S930, the process proceeds to step S950. In step S950, the deceleration proposal unit 31 sets the deceleration proposal display to stop, and the process proceeds to step S970.

[0132] In step S970, the deceleration suggestion unit 31 compares the deceleration suggestion display set in steps S940-S960 with the deceleration suggestion display set in the previous deceleration suggestion display process (one cycle ago) to determine whether the change from a stop to a request has occurred. If the deceleration suggestion display has changed from a stop to a request compared to one cycle ago, the process proceeds to step S980. In step S980, the deceleration suggestion unit 31 sets a single tone for the deceleration suggestion buzzer operation indicator and ends the process. Figure 11 The processing continues. On the other hand, if in step S970 the deceleration proposal display has not changed from a stop to a request compared to one cycle ago, the processing proceeds to step S990. In step S990, the deceleration proposal unit 31 sets the deceleration proposal buzzer operation indicator to stop, and the process ends. Figure 11 The processing.

[0133] By configuring the deceleration proposal display process as described above, the driver can be notified of the start of the deceleration proposal display by sounding a short, single-tone buzzer. Furthermore, since... Figure 11 The deceleration suggestion display is executed continuously and repeatedly in short cycles. Therefore, when the road surface changes or the driver reduces the vehicle speed through braking operations and no further deceleration is required, the deceleration suggestion display can be stopped quickly. The system can notify the driver of the deceleration suggestion at the appropriate time without misleading the driver.

[0134] Figure 12 This is a flowchart of the process for obtaining and displaying the license determination result. The process for obtaining and displaying the license determination result starts from... Figure 11 The processing of step S900 is called. In the display permission determination result acquisition processing, the deceleration proposal unit 31 sequentially performs the determinations of steps S1000 to S1070. If all the conditions of steps S1000 to S1070 are met, the processing of step S1080 is executed to set the permission for the display permission determination and end. Figure 12 On the other hand, if any of the conditions in steps S1000 to S1070 are not met, the deceleration proposal unit 31 executes the processing of step S1090, sets a prohibition on the display permission determination, and ends the process. Figure 12 The processing.

[0135] In step S1000, the deceleration suggestion unit 31 determines the fault detection process ( Figure 3 The result of step S160) is whether no fault was detected. If a fault is detected, there is a possibility of incorrect display or display at a time different from the expected time, therefore the display is disabled.

[0136] In step S1010, the deceleration proposal unit 31 determines whether the function stops detection processing ( Figure 3The result of step S170) is whether no function stop was detected. If a function stop is detected, there is a possibility of incorrect display or display at a time different from the expected time, therefore the display is disabled.

[0137] In step S1020, the deceleration suggestion unit 31 determines whether a display stop operation has been performed. A display stop operation refers to an operation by which the driver disables the deceleration suggestion function. If the deceleration suggestion function is disabled by a display stop operation, the display permission determination is set to prohibit.

[0138] The activation or deactivation of the deceleration suggestion function can be confirmed, for example, through the display on the vehicle 1's navigation screen or multi-information display, or by checking whether indicator lights are illuminated. This can be achieved by operating the touch panel on the navigation screen, using switches or levers located around the driver's seat such as on the steering wheel, or by voice commands from the driver. When the driver uses the vehicle 1 in environments where there is no risk of collision due to obstacles cutting in front of the vehicle, such as at a racetrack, the deceleration suggestion function can be deactivated without displaying complex deceleration suggestion messages. Furthermore, the deceleration suggestion function can be configured to switch between being activated and deactivated independently, or it can be linked to driver operation for activating or deactivating the AEB (Autonomous Emergency Braking) function. That is, the deceleration suggestion function can be activated when the AEB function is active, and deactivated when the AEB function is inactive.

[0139] In step S1030, the deceleration suggestion unit 31 determines whether the object detection unit 25 has detected an obstacle in front of the vehicle 1. If no obstacle is detected, the probability of collision is considered zero, and therefore the display is disabled. This reduces the problems caused by excessive display and improves safety by appropriately displaying the object when necessary.

[0140] Alternatively, instead of using the detection results from the object detection unit 25, the parallax information acquired by the parallax acquisition unit 22 can be used to confirm that there are no obstacles in front of the vehicle 1. For example, it can be determined whether there is a parallax of a certain size or larger on the vehicle 1's travel path or within a certain distance to the left or right of the vehicle 1's travel path. If it exists, it is determined that there is an obstacle in front; if it does not exist, it is determined that there is no obstacle in front. In this way, by using only parallax information to determine whether there are obstacles, for example, by detecting all three-dimensional objects of arbitrary shapes without performing pedestrian or vehicle pattern matching, it is possible to display the object to the driver even if there is a risk that a pedestrian may fly out of the shadow of the three-dimensional object.

[0141] In step S1040, the deceleration suggestion unit 31 determines whether the vehicle 1 is not following. The determination of whether following is in progress is based on the results of obstacle detection and classification by the object detection unit 25. Specifically, following is determined to be in progress if an obstacle is detected that meets all of the following conditions.

[0142] (1) Obstacles are objects that can move on the road, such as vehicles, motorcycles, bicycles, and pedestrians. They are three-dimensional objects that follow other vehicles.

[0143] (2) The lateral width of the obstacle is not narrower than the lateral width of vehicle 1 by a certain amount (e.g., 0.5m). This condition is set so that the obstacle with a small lateral width, such as a motorcycle, can be easily weaved through or avoided by steering, and therefore the display is not cancelled.

[0144] (3) It exists on the travel path of vehicle 1.

[0145] (4) The relative distance to vehicle 1 in the front-rear direction exists within the range of vehicle speed × 4 [s]. Since it is considered difficult to cut into within this range, it is deemed unnecessary to continue displaying it.

[0146] (5) The absolute value of the relative speed with vehicle 1 is within a certain speed range (e.g., 20 km / h). This condition is set so as not to be regarded as following when the speed difference is large, thereby preventing unnecessary deceleration proposals to stop.

[0147] When a vehicle is traveling in front of vehicle 1 and vehicle 1 is following that vehicle, and vehicle 1's travel path is exactly after the vehicle in front has passed, it is assumed that the risk of an accident is low because the vehicle is traveling on the same path. Therefore, if a suggestion to slow down is made while following, the driver may perceive this as excessive display and find the notification inconvenient. By disabling the display while following, such inconvenience can be prevented.

[0148] In step S1050, the deceleration proposal unit 31 determines the instrument control processing ( Figure 9 The result determines whether the warning display is set to stop, i.e., whether an AEB or FCW warning to the driver has not been issued. AEB or FCW warnings to the driver take precedence over the deceleration proposal function and represent a stronger braking action than the deceleration proposal's intended braking action. Therefore, to enable the driver to perform a stronger braking action, the deceleration proposal display is disabled, thus not hindering the AEB or FCW warning and improving safety.

[0149] Alternatively, the results of instrument control processing can be processed using AEB action processing instead of instrument control processing. Figure 4 ) and FCW motion processing ( Figure 5 The result indicates that neither AEB nor FCW will take action.

[0150] In step S1060, the deceleration suggestion unit 31 determines whether the speed limit device (SLD) control is inactive. SLD control refers to using the maximum speed set by the driver for vehicle 1, or the road speed limit read from traffic signs using a stereo camera 3, as the maximum vehicle speed. Even if the driver accelerates using the accelerator pedal or other means, the vehicle 1's speed will not exceed this maximum speed (e.g., by reducing engine output). SLD control being active means that vehicle 1 is already decelerating, and in this case, a deceleration suggestion is not needed. By disabling the display of deceleration suggestions during SLD control operation, excessive deceleration suggestions are not made to the driver, thus avoiding driver confusion.

[0151] By constructing the display license determination result acquisition process as described above, it is possible to prevent excessive or unnecessary slowdown proposal notifications.

[0152] Figure 13 This is a flowchart of the deceleration proposal determination result acquisition and processing. The deceleration proposal determination result acquisition and processing starts from... Figure 11 The process called in step S920. In step S1100, the deceleration proposal unit 31 obtains the road surface category estimation result given by the road surface estimation unit 26. In step S1110, the deceleration proposal unit 31 uses the road surface category obtained in step S1100 to obtain the deceleration proposal threshold for making a deceleration proposal.

[0153] Figure 14 This is a diagram illustrating an example of a deceleration proposal threshold table. Pre-stored in non-volatile memory 12... Figure 14 The deceleration proposal threshold table 60 is shown. In the deceleration proposal threshold table 60, a deceleration proposal threshold corresponding to each road surface category is stored. The deceleration proposal unit 31, through... Figure 14 The deceleration proposal threshold is obtained by referring to the road surface category obtained in step S1100 in the deceleration proposal threshold table 60.

[0154] The deceleration proposal threshold stored in the deceleration proposal threshold table 60 is a pre-calculated value for a speed where the braking distance is longer than the AEB main braking action distance. The braking distance at this time is the braking distance traveled before the vehicle speed reaches 0 when decelerating with maximum braking force on a road of the corresponding road type, obtained experimentally using vehicle 1. Furthermore, the AEB main braking action distance at this time refers to the distance that, assuming a stationary object in front of vehicle 1 (an obstacle with a relative speed of 0 km / h and a 100% overlap rate relative to the front and rear of vehicle 1), would move relative to the stationary object in front of vehicle 1 at the current vehicle speed under the control of AEB main braking, obtained through testing... Figure 4The collision probability judgment distance used in step S310 is calculated based on the vehicle speed.

[0155] Additionally, if the deceleration proposal was displayed as a request during execution one cycle ago, it is preferable to subtract a certain amount (e.g., 5 km / h) from the obtained deceleration proposal threshold before using it. By setting a certain lag range in this way, it is possible to prevent the judgment result from changing frequently when driving at a speed close to the deceleration proposal threshold stored in the deceleration proposal threshold table 60, thus avoiding inconvenience to the driver regarding notifications.

[0156] In addition, to prevent false displays of deceleration suggestions, if the road surface estimation unit 26 fails to estimate the road surface type, it is preferable to set the deceleration suggestion threshold to the same level as that for paved roads (dry).

[0157] In step S1120, the deceleration suggestion unit 31 compares the vehicle speed of vehicle 1 with the deceleration suggestion threshold obtained in step S1110 to determine whether the vehicle speed exceeds the deceleration suggestion threshold. If the vehicle speed exceeds the deceleration suggestion threshold, the process proceeds to step S1130. In step S1130, the deceleration suggestion unit 31 displays the deceleration suggestion settings and the process ends. Figure 13 The processing proceeds to step S1140 if the vehicle speed does not exceed the deceleration proposal threshold in step S1120. In step S1140, the deceleration proposal unit 31 sets the deceleration proposal to stop, thus ending the process. Figure 13 The processing.

[0158] By constructing the deceleration proposal determination result acquisition and processing as described above, safety during AEB activation can be improved. Furthermore, even if AEB does not activate, the likelihood of the driver avoiding a collision by performing braking operations is increased, further enhancing safety.

[0159] According to the first embodiment described above, the following effects are achieved.

[0160] (1) The computing device 11 estimates the road surface type based on an image of the road surface in front of the vehicle 1 (the vehicle itself), compares the vehicle speed (state) of the vehicle 1 (the vehicle itself) with a deceleration proposal threshold (threshold) related to the vehicle speed (state) of the vehicle 1 (the vehicle itself) determined according to the road surface type, and notifies the driver of the vehicle 1 (the vehicle itself) of a deceleration operation proposal based on the comparison result. Therefore, the risk of collision accidents when driving on roads with low road resistance can be reduced.

[0161] (2) The computing device 11 determines whether to perform automatic deceleration control of vehicle 1 (this vehicle) based on the relative position and relative speed of the obstacle in front of vehicle 1 (this vehicle). The deceleration proposal threshold (threshold) is determined according to the road surface type and the braking force of automatic deceleration control. Therefore, it is possible to increase the deceleration when automatic deceleration control is performed earlier, increase the deceleration amount, and further improve the safety of vehicle 1.

[0162] (3) The state of vehicle 1 (this vehicle) is the speed of vehicle 1 (this vehicle), and the proposed deceleration threshold (threshold) is set to the speed at which a collision between vehicle 1 (this vehicle) and an obstacle in front of it can be avoided. Therefore, the risk of collision accidents when driving on roads with low road resistance can be reduced.

[0163] (4) The road surface category includes unpaved roads, which include dirt roads and gravel roads. Therefore, especially on unpaved roads where road resistance is low, deceleration can be proposed earlier, improving the safety of vehicle 1.

[0164] (5) The computing device 11 informs the driver of the risk of collision with an obstacle based on the relative position and relative speed, with a higher priority than the deceleration proposal. Therefore, the deceleration proposal does not interfere with the warnings of AEB or FCW, and can reduce the inconvenience felt by the driver while maintaining safety.

[0165] (6) The computing device 11 detects three-dimensional objects located in front of the vehicle 1 (the vehicle) based on an image obtained by photographing the front of the vehicle 1 (the vehicle itself). If no three-dimensional object larger than a specified size is detected, the device does not notify the driver of a deceleration operation suggestion. Therefore, the frequency of deceleration suggestion notifications is reduced in scenarios where deceleration is not required, thus reducing the inconvenience felt by the driver.

[0166] (7) The arithmetic unit 11 calculates the relative position of a three-dimensional object located in front of the vehicle 1 (the vehicle) and the vehicle 1 (the vehicle) based on an image obtained by capturing the front of the vehicle 1 (the vehicle itself). Based on the relative speed of the three-dimensional object and the vehicle 1 (the vehicle) based on the change in relative position per unit time, it determines whether to perform automatic deceleration control of the vehicle 1 (the vehicle itself), and determines the braking force of the automatic deceleration control based on the road surface type. Therefore, it is possible to increase the deceleration rate when performing automatic deceleration control earlier, increase the deceleration amount, and further improve the safety of the vehicle 1.

[0167] (8) The calculation device 11 suppresses the operation of the anti-lock braking system according to the type of road surface. Therefore, on roads where the braking distance is shorter when the ABS is not activated, the risk of collision accidents can be reduced.

[0168] <Second Implementation Method>

[0169] Reference Figure 15 The second embodiment of the vehicle driving assistance device of the present invention will be described. Furthermore, for components that are identical or equivalent to those described in the first embodiment, the differences will be mainly explained.

[0170] In the first embodiment, the deceleration proposal determination result acquisition process ( Figure 13 A deceleration suggestion threshold is obtained for comparison with vehicle speed corresponding to various road surface types. However, in situations where road resistance is very low, such as on snow-covered or icy roads, skidding can occur even when waiting at a traffic light or stopping. Therefore, drivers are more likely to suppress their speed from normal driving conditions, recognizing the danger of driving at higher speeds. Furthermore, even on wet conditions such as paved roads, where road resistance is high, AEB can effectively provide the necessary deceleration. Therefore, suggesting a speed reduction does not necessarily improve safety. Thus, if a system is established that identifies and suggests a deceleration in environments where normal driving (i.e., driving at a deceleration of 4 m / ss or less) is possible, but not in situations requiring AEB (such as dirt or gravel roads), then this system can reduce the cost of estimating road surface types and reliably convey risks that are difficult for drivers to notice.

[0171] Figure 15 Is with Figure 14 The same figure is an example of a deceleration proposal threshold table in the second embodiment. Figure 15 The deceleration proposal threshold table 600 shown is configured with three categories: gravel and soil as road surface categories, and in cases where the road surface is neither gravel nor soil, a large, normally unused value (400) is used as the deceleration proposal threshold. This large, normally unused value represents an invalid value.

[0172] According to the second embodiment described above, the following effects are achieved.

[0173] (1) Only gravel and soil, and other classifications, are used as road surface categories. This reduces the cost of estimating road surface categories and accurately conveys risks that drivers may not notice.

[0174] <Third Implementation Method>

[0175] Reference Figure 16 The third embodiment of the vehicle driving assistance device of the present invention will be described. Furthermore, for components that are identical or equivalent to those described in the first embodiment, the main differences will be explained.

[0176] In the second embodiment described above, by setting the deceleration proposal threshold table to something different from that in the first embodiment, the processing itself is not changed, the cost of estimating road surface categories is suppressed, and risks that are difficult for drivers to notice are reliably communicated. In the third embodiment described below, a deceleration proposal determination result acquisition process is performed without using the deceleration proposal threshold table. Figure 13 To further reduce costs, the company is taking advantage of the fact that gravel and dirt roads have similar road resistance and classifying them as "unpaved".

[0177] Figure 16 Is with Figure 13 The same diagram is a flowchart of the deceleration proposal determination result acquisition process in the third embodiment. In step S1200, the deceleration proposal unit 31 acquires the road surface estimation result of the road surface estimation unit 26 regarding the road surface category. At this time, if the road surface category estimation result is gravel or soil, the road surface category is replaced with unpaved. In step S1210, the deceleration proposal unit 31 determines whether the road surface category acquired in step S1200 is unpaved. If the road surface category is not unpaved, the process proceeds to step S1250. In step S1250, the deceleration proposal unit 31 sets the deceleration proposal to stop, and the process ends. Figure 16 The processing.

[0178] On the other hand, if the road surface category is unpaved in step S1210, the process proceeds to step S1220. In step S1220, the deceleration suggestion unit 31 determines whether the vehicle speed is faster than 40 km / h. If the vehicle speed is faster than 40 km / h, the process proceeds to step S1230. In step S1230, the deceleration suggestion unit 31 displays the deceleration suggestion setting and the process ends. Figure 16 The processing continues. On the other hand, if the vehicle speed is not higher than 40 km / h in step S1220, the processing proceeds to step S1240. In step S1240, the deceleration suggestion unit 31 sets the deceleration suggestion to stop, and the process ends. Figure 16 The processing.

[0179] According to the third embodiment described above, the following effects are achieved.

[0180] (1) The deceleration suggestion unit 31 uses a fixed value (40 km / h) as the deceleration suggestion threshold when the road surface category is unpaved, and does not make a deceleration suggestion when the road surface is not unpaved. As a result, there is no need to perform a deceleration suggestion threshold table retrieval process, which can achieve simple and low-cost installation and improved safety.

[0181] <Fourth Implementation Method>

[0182] Reference Figure 17The fourth embodiment of the present invention describes a vehicle driving assistance device. Furthermore, reference numerals are used to denote components that are identical or equivalent to those described in the first embodiment; the main differences are explained.

[0183] In the first embodiment, the vehicle speed of vehicle 1 is used as the state of vehicle 1 compared with a threshold. Therefore, the threshold (deceleration proposal threshold) used for comparison also represents the vehicle speed. A state other than vehicle speed can also be used as the state of vehicle 1 compared with the threshold. In the fourth embodiment, an example using distance instead of vehicle speed is described.

[0184] Figure 17 Is with Figure 13 The same diagram is a flowchart of the deceleration proposal determination result acquisition process in the fourth embodiment. In step S1300, the deceleration proposal unit 31 acquires the road surface estimation result of the road surface estimation unit 26 regarding the road surface category. In step S1310, the deceleration proposal unit 31 acquires the collision probability judgment distance (AEB main braking distance) at a vehicle speed and an overlap rate of 100%. In step S1320, the deceleration proposal unit 31 calculates the braking distance of vehicle 1 using the vehicle speed acquired in step S1310 and the road surface category acquired in step S1300. In step S1330, the deceleration proposal unit 31 compares the AEB main braking distance acquired in step S1310 with the braking distance calculated in step S1320, and determines whether the AEB main braking distance is shorter than the braking distance. If the AEB main braking distance is shorter than the braking distance, the process proceeds to step S1340. In step S1340, the deceleration proposal unit 31 displays the deceleration proposal settings and ends the process. Figure 17 The processing proceeds to step S1350 if, in step S1330, the AEB main braking action distance is not shorter than the braking distance. In step S1350, the deceleration proposal unit 31 sets the deceleration proposal to stop, thus ending the process. Figure 17 The processing.

[0185] As mentioned above, Figure 17 The deceleration proposal determination result acquisition process shown involves directly installing the calculation method for the parameters used to design the deceleration proposal threshold table as part of the software installation. Therefore, this differs from a deceleration proposal threshold table calculated before software installation. Figure 13 Compared to the treatment, Figure 17 The computational cost of processing increases. However, when the method for obtaining the collision probability assessment distance is adjusted due to changes in the characteristics and concept of vehicle 1, there is no need to redesign the deceleration proposal threshold table, which has the advantage of low maintenance costs.

[0186] According to the fourth embodiment described above, the following effects are achieved.

[0187] (1) The state of vehicle 1 (this vehicle) is the distance required for vehicle 1 (this vehicle) to stop, and the threshold is the distance from vehicle 1 (this vehicle) to an obstacle existing in front of vehicle 1 (this vehicle). Therefore, even if the method for obtaining the distance for judging the probability of collision is adjusted due to changes in the characteristics and concept of vehicle 1, there is no need to redesign the deceleration proposal threshold table, thus reducing maintenance costs.

[0188] <Fifth Implementation>

[0189] Reference Figure 18 The fifth embodiment of the vehicle driving assistance device of the present invention will be described. Furthermore, for components that are identical or equivalent to those described in the first embodiment, the main differences will be explained.

[0190] In the first embodiment, the vehicle speed of vehicle 1 is used as the state of vehicle 1 compared with a threshold. Therefore, the threshold (deceleration proposal threshold) to which it is compared also represents the vehicle speed. A state other than vehicle speed can also be used as the state of vehicle 1 compared with the threshold. In the fifth embodiment, an example of using deceleration instead of vehicle speed is described.

[0191] Figure 18 Is with Figure 13 The same diagram is a flowchart of the deceleration proposal determination result acquisition process in the fifth embodiment. In step S1400, the deceleration proposal unit 31 acquires the road surface estimation result of the road surface estimation unit 26 regarding the road surface category. In step S1410, the deceleration proposal unit 31 acquires the AEB deceleration corresponding to the vehicle speed. The AEB deceleration refers to the deceleration value set for each vehicle speed required to initiate AEB main braking, obtained in advance through experiments or theoretical calculations. The deceleration proposal unit 31 acquires the AEB deceleration corresponding to the vehicle speed, for example, by using calculations of a prescribed mathematical formula or by referring to a table storing the AEB deceleration for each vehicle speed. In step S1420, the deceleration proposal unit 31 acquires the deceleration limit value corresponding to the road surface category. The deceleration proposal unit 31 acquires the value stored in the... Figure 7 The road resistance values ​​in the illustrated road resistance table 50 are used as deceleration limit values.

[0192] In step S1430, the deceleration proposal unit 31 compares the AEB deceleration obtained in step S1410 with the deceleration limit value obtained in step S1420, and determines whether the AEB deceleration is greater than the deceleration limit value. If the AEB deceleration is greater than the deceleration limit value, the process proceeds to step S1440. In step S1440, the deceleration proposal unit 31 displays the deceleration proposal setting and ends the process. Figure 18The processing proceeds to step S1450 because, in this case, it is considered that the deceleration performance of AEB cannot be utilized. On the other hand, if the AEB deceleration is not greater than the deceleration limit value in step S1430, the processing proceeds to step S1450. In this case, since it is considered that the deceleration performance of AEB can be utilized, in step S1450, the deceleration proposal unit 31 sets the deceleration proposal to stop, and the process ends. Figure 18 The processing.

[0193] Furthermore, in step S1420, the deceleration suggestion unit 31 can also perform various corrections to the deceleration limit value. For example, it can detect whether the vehicle 1 is equipped with studless anti-skid tires or whether the tires are equipped with snow chains. If the vehicle 1 increases road resistance by using studless anti-skid tires or snow chains, the deceleration suggestion unit 31 corrects the deceleration limit value to a higher value (e.g., by adding a predetermined correction value or multiplying by a predetermined correction coefficient greater than 1). As another example, it stores the occurrence of deceleration when braking on the same road surface in the past, and performs corrections to offset the difference if there is a difference from the parameters stored in the road resistance table 50. In this way, road resistance can be corrected and learned successively, improving the accuracy of the threshold. In addition, as another example, if it is determined from the image data output by the stereo camera 3 that the driving path ahead of the vehicle 1 is a curve, the deceleration limit value is corrected according to the curvature of the curve. Specifically, when driving on roads with high curvature, the force applied to the lateral side of vehicle 1 reduces the force of the tires gripping the road in the longitudinal direction. Therefore, in cases of high curvature, a correction is implemented by reducing the deceleration limit. Alternatively, multiple corrections can be combined.

[0194] According to the fifth embodiment described above, the following effects are achieved.

[0195] (1) The state of vehicle 1 (this vehicle) is the deceleration required to stop vehicle 1 (this vehicle) in front of an obstacle by automatic deceleration control. The threshold is the deceleration that vehicle 1 (this vehicle) can generate under the premise of road resistance corresponding to the road surface type. Therefore, the risk of collision accidents when driving on roads with low road resistance can be reduced.

[0196] (2) The calculation device 11 estimates the curve radius of the predetermined travel path of the vehicle 1 (the vehicle itself). The smaller the curve radius, the easier it is to notify the deceleration operation suggestion. Therefore, it is possible to more accurately determine the threshold for making a deceleration suggestion that matches the shape of the road, thereby improving safety while reducing the hassle of deceleration suggestions.

[0197] The following variations are also within the scope of the present invention. The configurations shown in the variations can be combined with the configurations described in the above embodiments, or the configurations described in the different embodiments described above, or the configurations described in the different variations below can be combined.

[0198] <Variation Example 1>

[0199] The configuration of the second embodiment, specifically designed for high-risk earthen pavements, can also be combined with the third or fourth embodiment. In this case, the advantages of using distance or acceleration for comparison can be obtained while reducing computational costs.

[0200] <Variation Example 2>

[0201] exist Figure 12 In step S1040 of the process for obtaining the permission determination result, it is determined whether there is a vehicle following the vehicle in front. However, it is also possible to further add whether the vehicle 1 is traveling on a highway to the determination condition. For example, the determination in step S1040 can be made if there is no following or if vehicle 1 is not traveling on a highway. In other words, if following is performed in step S1040 and vehicle 1 is traveling on a highway, the process can proceed to step S1080.

[0202] Furthermore, any method can be used to determine whether vehicle 1 is traveling on a highway. For example, traffic signs specific to highways can be identified based on image data acquired from stereo camera 3, or the vehicle's position can be determined using a Global Navigation Satellite System, and then compared with pre-prepared map data.

[0203] By configuring it as described above, the scenario in which the suggestion to prohibit deceleration during following is limited to highway driving. In other words, the computing device 11 does not notify the vehicle 1 (this vehicle) of a deceleration operation suggestion when the vehicle is traveling on a dedicated motor vehicle lane. On ordinary roads, the risk of obstacles cutting into the road is high. In addition, the frequency of road branching or merging on ordinary roads is higher than on highways, and even when following, it is conceivable that an obstacle might be suddenly detected in front of this vehicle when the vehicle in front changes its course. Therefore, by limiting the scenario in which the suggestion to prohibit deceleration to highway driving, safety can be improved.

[0204] <Variation Example 3>

[0205] The above-described embodiment is an example using a stereo camera 3 with a pair of left and right cameras. The present invention is not limited to this embodiment. For example, a monocular camera may be used instead of a stereo camera to implement each embodiment.

[0206] The embodiments of the present invention have been described above. However, the above embodiments only represent a part of the application examples of the present invention and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0207] Symbol Explanation

[0208] 1…Vehicle (this vehicle), 2…Vehicle driving assistance device, 3…Stereo camera, 4…Brake control device, 5…Instrument control device, 6…Brake device, 7…Buzzer, 8…Display device, 11…Arithmetic unit, 12…Non-volatile memory, 13…Volatile memory, 14…Input / output interface, 50…Road resistance gauge, 60, 600…Deceleration suggestion threshold table.

Claims

1. A driving assistance device for a vehicle, comprising a computing unit, The vehicle driving assistance device is characterized in that... The computing device estimates the type of the road surface based on an image of the road surface in front of the vehicle, compares the state of the vehicle with a threshold related to the state of the vehicle determined based on the type of the road surface, and notifies the driver of the vehicle of a suggestion to slow down based on the comparison result.

2. The vehicle driving assistance device according to claim 1, characterized in that, The computing device determines whether to implement automatic deceleration control for the vehicle based on the relative position and relative speed of the obstacle in front of the vehicle and the vehicle itself. The threshold is determined based on the type of road surface and the braking force of the automatic deceleration control.

3. The vehicle driving assistance device according to claim 1, characterized in that, The state of the vehicle is its speed, and the threshold is the speed at which a collision between the vehicle and an obstacle in front of it can be avoided.

4. The vehicle driving assistance device according to claim 1, characterized in that, The road surface category includes unpaved roads, which include dirt roads and gravel roads.

5. The vehicle driving assistance device according to claim 1, characterized in that, The state of the vehicle is the distance required for the vehicle to stop, and the threshold is the distance from the vehicle to an obstacle in front of the vehicle.

6. The vehicle driving assistance device according to claim 2, characterized in that, The state of the vehicle is the deceleration required by the automatic deceleration control to stop the vehicle in front of an obstacle, and the threshold is the deceleration that the vehicle can generate under the premise of road resistance corresponding to the type of road surface.

7. The vehicle driving assistance device according to claim 2, characterized in that, The computing device informs the driver of the risk of collision with the obstacle with a higher priority than the proposed deceleration operation, based on the relative position and the relative speed.

8. The vehicle driving assistance device according to claim 1, characterized in that, The computing device obtains an image from the front of the vehicle, detects three-dimensional objects located in front of the vehicle, and does not notify the proposal of deceleration operation if no three-dimensional object larger than a specified size is detected.

9. The vehicle driving assistance device according to claim 1, characterized in that, The computing device estimates the radius of the curves along the predetermined path of the vehicle's travel. The smaller the radius of the curve, the easier it is to notify the vehicle of the deceleration operation proposal.

10. The vehicle driving assistance device according to claim 1, characterized in that, The computing device calculates the relative position of a three-dimensional object located in front of the vehicle and the vehicle based on an image obtained by capturing the front of the vehicle, determines whether to perform automatic deceleration control of the vehicle based on the relative speed of the three-dimensional object and the vehicle based on the change in the relative position per unit time, and determines the braking force of the automatic deceleration control based on the type of road surface.

11. The vehicle driving assistance device according to claim 1, characterized in that, The computing device suppresses the operation of the anti-lock braking system based on the type of road surface.

12. The vehicle driving assistance device according to claim 1, characterized in that, The computing device does not notify the proposed deceleration operation when the vehicle is traveling on a dedicated motor vehicle road.

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