Vehicle control system

Abstract

To provide a vehicle control system capable of performing proper automatic brake control according to the surrounding environment of a vehicle.SOLUTION: A vehicle control system 1 includes: a collision determination section 21a that determines a possibility of collision with a target obstacle present in front of a vehicle; a brake control section 21c that controls braking force so as to perform automatic brake control according to the collision possibility determined by the collision determination section 21a; an environment determination section 22 that determines a surrounding environment of the vehicle; and an adjustment section 23 that changes a type of the target obstacle in the automatic brake control according to the surrounding environment of the vehicle determined by the environment determination section 22.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control system. [Background technology]

[0002] Systems that support safety when a collision between a vehicle and an obstacle ahead is predicted are being put into practical use. Known safety support systems include a collision mitigation braking system that automatically activates the brakes and / or an alarm, and a so-called pedestrian airbag system that protects a person in a collision with a vehicle. Patent Document 1 discloses a protection control device that activates a protection device to protect a collided object when the output of a collision sensor corresponding to the impact applied during a collision between the object and the vehicle exceeds a collision detection threshold. In the device of Patent Document 1, the object is a specific object, including a bicycle and a bicycle rider, and the collision detection threshold is set to a low threshold when an obstructing environment, such as rain or fog, occurs that obstructs recognition of the object before the collision. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-081428 Summary of the Invention [Problem to be solved by the invention]

[0004] The protection control device described in the aforementioned Patent Document 1 changes the collision determination threshold based on whether the object is a specific object and whether an obstructing environment, such as rain or fog, is occurring. Even in a system that performs collision mitigation braking control when a collision between a vehicle and an obstacle is predicted, it is desirable to perform control taking into account the environment around the vehicle. For example, in an environment where multiple types of obstacles, including four-wheeled vehicles, motorcycles, and pedestrians, are present around the vehicle, performing automatic braking control targeting the obstacle ahead may cause the vehicle to slow down, potentially resulting in a rear-end collision with a following vehicle. In this case, the reliability and safety of the system are reduced. On the other hand, in an environment where there are few obstacles around the vehicle, it is desirable to reliably perform automatic braking control when there is a possibility of a collision with an obstacle. In other words, it is desirable to improve the safety and reliability of the system and perform appropriate automatic braking control according to the environment around the vehicle.

[0005] The present invention has been made in consideration of the above-described circumstances, and its purpose is to provide a vehicle control system that can execute appropriate automatic brake control in accordance with the surrounding environment of the vehicle. [Means for solving the problem]

[0006] According to one aspect of the present invention, a vehicle control system includes a collision determination unit that determines the possibility of a collision with a target obstacle present in front of the vehicle, a brake control unit that controls braking force to perform automatic brake control in accordance with the possibility of collision determined by the collision determination unit, an environment determination unit that determines the surrounding environment of the vehicle, and an adjustment unit that changes the type of target obstacle in the automatic brake control in accordance with the surrounding environment of the vehicle determined by the environment determination unit. [Effects of the Invention]

[0007] The vehicle control system according to the present invention can execute appropriate automatic brake control in accordance with the surrounding environment of the vehicle. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a vehicle control system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart showing the flow of collision damage mitigation brake control in the first embodiment. [Figure 3] FIG. 3 is a flowchart showing the flow of a specific environment determination process in the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] -First embodiment- DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle control system according to a first embodiment of the present invention will now be described in detail with reference to the drawings. Fig. 1 is a block diagram showing a schematic configuration of the vehicle control system according to this embodiment.

[0010] 1, the vehicle control system 1 includes, for example, an obstacle detection device 10 that detects obstacles around the vehicle, a vehicle speed sensor 11 that detects the vehicle speed, a positioning device 12 that acquires vehicle position information, a map information database 13, an operation input device 14, a control device 20 that performs control related to collision damage mitigation brake control of the vehicle, a brake device 30, and an alarm device 40. The vehicle control system 1 according to this embodiment is configured to be mounted on the vehicle and to execute control related to collision damage mitigation brake control of the vehicle. Optionally, the vehicle control system 1 may further include an ambient environment acquisition device 15 that acquires environmental information around the vehicle, and a display device 50.

[0011] The obstacle detection device 10 is configured to detect obstacles around the vehicle and measure the relative position and relative distance (inter-vehicle distance) between the vehicle and the obstacle. For example, a millimeter-wave radar, a camera, a sonar sensor, or a LiDAR (Light Detection and Ranging) can be used as the obstacle detection device 10. The detection of obstacles by the obstacle detection device 10 is dynamically performed at a predetermined measurement period. Information about the obstacles detected by the obstacle detection device 10 and the vehicle speed detected by the vehicle speed sensor 11 are input to the control device 20.

[0012] The positioning device 12 is configured to acquire vehicle position information based on information from, for example, a Global Navigation Satellite System (GNSS), etc. The vehicle position information acquired by the positioning device 12 and the map information in the map information database 13 are input to the control device 20.

[0013] The operation input device 14 is configured to accept various operation inputs to the vehicle by a user, for example, a driver. The operation input device 14 includes a function changeover switch that is operated by the driver to enable or disable the function changeover of the collision damage mitigation brake control. The operation input device 14 may be configured as, for example, a touch panel integrated with the display of the alarm device 40 or the display device 50 described below.

[0014] The surrounding environment acquisition device 15 is composed of various detection means for acquiring information about the environment around the vehicle. The surrounding environment acquisition device 15 will be described later.

[0015] The control device 20 is configured by a computer including, for example, a ROM that stores programs and data, a CPU that performs arithmetic processing, a RAM that stores dynamic data and arithmetic processing results, an input / output interface, etc. The control device 20 is configured to execute the functions of an AEB control unit 21, an environment determination unit 22, an adjustment unit 23, etc., and to control the entire vehicle control system 1. Note that the vehicle control system 1 may also implement the AEB control unit 21 as a controller separate from the control device 20.

[0016] The AEB control unit 21 is configured to execute so-called Autonomous Emergency Braking (AEB) control, which issues a warning to the driver and / or activates automatic braking depending on the possibility of collision between the vehicle and an obstacle. The collision mitigation braking control executed by the AEB control unit 21 includes warning control, in which the warning device 40 issues a warning to prompt the driver to apply the brakes when it is determined that there is a risk of collision with an obstacle, and automatic braking control, in which the brake device 30 generates a strong braking force when it is determined that there is a high possibility of collision with an obstacle. The AEB control unit 21 has, for example, a collision determination unit 21a, a warning control unit 21b, and a brake control unit 21c.

[0017] The collision determination unit 21a is configured to determine the possibility of a collision between the vehicle and an obstacle based on the relative distance to the obstacle ahead of the vehicle input from the obstacle detection device 10. The collision determination unit 21a can calculate, for example, a collision prediction time TTC (Time-To-Collision) required for the vehicle to approach and come into contact with the obstacle as the collision possibility. Specifically, the collision determination unit 21a calculates the relative speed between the vehicle and the obstacle, which represents the change in relative distance per unit time, from the relative distance to the obstacle, and calculates the collision prediction time TTC as a value obtained by dividing the relative distance by the relative speed.

[0018] The warning control unit 21b is configured to issue a warning by the notification device 40 when the collision prediction time TTC calculated by the collision determination unit 21a is equal to or less than a preset first predetermined value TTC1. The brake control unit 21c is configured to control the brake device 30 so as to generate a braking force equivalent to the maximum deceleration of the system, for example, when the collision prediction time TTC calculated by the collision determination unit 21a is equal to or less than a preset second predetermined value TTC2. The second predetermined value TTC2 is smaller than the first predetermined value TTC1.

[0019] The braking device 30 includes a brake (e.g., a disc brake, a drum brake, etc.) provided on the wheel, a brake actuator connected to the brake via hydraulic piping, and a brake controller, and is configured to control the hydraulic pressure in accordance with a deceleration command from the control device 20 and control the braking force of the brake.

[0020] The notification device 40 is configured to issue an alarm in response to a command from the control device 20 when there is a possibility of a collision with an obstacle. The notification device 40 may have, for example, a display, indicator lights, a speaker, etc., arranged on an instrument panel at the front of the vehicle, and can issue a warning to the driver visually and / or audibly. The notification device 40 may also be configured to issue a warning through the sense of touch, for example. The display device 50 is configured, for example, by a liquid crystal display installed on the instrument panel, and is configured to display an image on the display screen in response to a command from the control device 20.

[0021] As described above, the vehicle control system 1 according to this embodiment is configured to perform warning control and automatic braking control using the AEB control unit 21 in response to the possibility of a collision between the vehicle and an obstacle ahead of the vehicle. Here, obstacles present around the vehicle include various types of objects, such as four-wheeled vehicles, two-wheeled vehicles, bicycles, and pedestrians. The surrounding environment of the vehicle, such as the types and amounts of obstacles present around the vehicle, may vary depending on, for example, the region in which the vehicle is traveling. Furthermore, driver characteristics, such as the distance the driver maintains between the vehicle and a preceding vehicle during normal driving, may also vary depending on the region.

[0022] In some regions or countries, drivers tend to drive closely in crowded urban areas and other situations where there are many vehicles, motorcycles, and pedestrians. In such environments, implementing collision mitigation braking control for all types of obstacles may result in excessive execution of warning control and automatic braking control. In some situations, automatic braking control may slow the vehicle down, potentially inducing a collision between the vehicle and a following vehicle. This may result in a loss of safety and reliability of the system. On the other hand, in environments where there are few obstacles around the vehicle and the possibility of a rear-end collision from a following vehicle is low, it is expected that automatic braking control will be reliably executed when there is a high possibility of a collision with an obstacle in front of the vehicle.

[0023] Therefore, in this embodiment, the control is adjusted to execute appropriate collision mitigation brake control according to the vehicle's surrounding environment. For example, when the vehicle's surrounding environment is a specific environment (described later), the control device 20 restricts the collision mitigation brake control compared to when the vehicle's surrounding environment is not the specific environment. In other words, when the vehicle's surrounding environment is not the specific environment, the collision mitigation brake control is extended compared to when the vehicle's surrounding environment is the specific environment.

[0024] Specifically, when the vehicle's surrounding environment is a specific environment, the control device 20 is configured to reduce the types of obstacles (target obstacles) to be controlled in the collision damage mitigation brake control and limit the functions (control content), and when the vehicle's surrounding environment is not a specific environment, the control device 20 is configured to increase the types of target obstacles and expand the functions. The adjustment of the collision damage mitigation brake control will be described in detail below.

[0025] In order to adjust the collision mitigation brake control, the control device 20 has an environment determination unit 22 and an adjustment unit 23. The environment determination unit 22 is configured to determine whether the environment around the vehicle is a specific environment for adjusting the collision mitigation brake control, based on information input from the obstacle detection device 10, the vehicle speed sensor 11, the positioning device 12, etc.

[0026] In this embodiment, a specific environment refers to an environment in which the effect of the collision mitigation brake control may not be fully achieved by targeting all types of obstacles present around the vehicle. For example, in an environment such as an urban area or a busy shopping district where multiple types of obstacles are present, executing automatic brake control may actually induce a collision between the vehicle and the obstacle. Therefore, an environment in which multiple types of obstacles are densely packed, such as an urban area or a busy shopping district, can be specified as a specific environment. On the other hand, in an environment such as a suburban or rural area where multiple types of obstacles are not densely packed, it is expected that the function of the collision mitigation brake control can be fully demonstrated by targeting the obstacles present there. Therefore, an environment in which multiple types of obstacles are not densely packed, such as a suburban or rural area, can be specified as a non-specific environment.

[0027] The environment determination unit 22 can set the following surrounding environments of the vehicle as specific environments, for example. (A) If the vehicle's current location is within a predetermined geographic area (B) When the density of obstacles within a predetermined range around the vehicle is higher than a predetermined value. (C) When there is a possibility of contact between the vehicle and a vehicle following the vehicle. Each case will be explained below.

[0028] (A) If the vehicle's current location is within a predetermined geographic area The predetermined geographical area includes, for example, an area classified as an urban area or a busy street, i.e., an area where multiple types of obstacles (e.g., pedestrians, bicycles, and vehicles) are expected to be present. Information regarding the predetermined geographical area is, for example, set in advance in the map information database 13. The environment determination unit 22 can determine that the surrounding environment of the vehicle is a specific environment when the current position of the vehicle is within the predetermined geographical area based on the vehicle position information input from the positioning device 12 and the map information input from the map information database 13. The environment determination unit 22 may also determine whether the vehicle is traveling in an area classified as an urban area or a busy street, i.e., within the predetermined geographical area, based on image data of the area ahead of the vehicle input from the obstacle detection device 10 and the vehicle speed acquired from the vehicle speed sensor 11. For example, the environment determination unit 22 can determine that the vehicle is traveling in an area classified as an urban area or a busy street when multiple buildings are lined up along the road ahead of the vehicle and the vehicle is traveling at a low speed.

[0029] (B) When the density of obstacles within a predetermined range around the vehicle is higher than a predetermined value. The environment determination unit 22 can determine whether the environment around the vehicle is a specific environment based on the density of obstacles within a predetermined range around the vehicle. The environment determination unit 22 identifies the type of obstacle using a technique such as pattern matching based on the obstacle information input from the obstacle detection device 10, and calculates the density of the specific obstacle within the predetermined range. Here, the specific obstacle may be, for example, a pedestrian. The environment determination unit 22 can determine that the environment around the vehicle is a specific environment when the density of obstacles is higher than a predetermined value, for example, when the area around the vehicle is crowded with pedestrians.

[0030] The above cases (A) and (B) are congested areas such as urban areas and downtown areas where multiple types of obstacles are present, and these areas are set as specific environments from the perspective that if collision damage mitigation brake control is executed for all types of obstacles, the full effect of collision damage mitigation brake control may not be achieved.

[0031] (C) When there is a possibility of contact between the vehicle and a vehicle following the vehicle. The environment determination unit 22 can determine whether the environment around the vehicle is a specific environment based on whether there is a following vehicle behind the vehicle that may come into contact with the vehicle. For example, if automatic braking control is executed in response to the possibility of a collision between the vehicle and an obstacle ahead, and the following vehicle is traveling at a close distance, the vehicle may decelerate and be rear-ended by the following vehicle. In such a case, the safety of the system and user trust in the system may be reduced. Therefore, in order to limit collision damage mitigation braking control when there is a possibility of contact with the following vehicle, the possibility of contact with the following vehicle is set as a specific environment.

[0032] The environment determination unit 22 calculates the predicted time to collision TTC between the vehicle and the following vehicle based on the relative distance and relative speed between the vehicle and a vehicle (following vehicle) present behind the vehicle detected by the obstacle detection device 10. The environment determination unit 22 preferably calculates changes in the relative distance and relative speed between the vehicle and the following vehicle based on the deceleration of the vehicle for executing automatic braking control, and calculates the predicted time to collision TTC between the vehicle and the following vehicle when automatic braking control is executed. If the predicted time to collision TTC between the vehicle and the following vehicle is smaller than a preset value and there is a possibility that the vehicle and the following vehicle will come into contact as a result of executing automatic braking control, it can be determined that the environment around the vehicle is a specific environment.

[0033] In addition to the above cases (A) to (C), the environment determination unit 22 can also determine whether the environment around the vehicle is a specific environment based on environmental information around the vehicle input from the ambient environment acquisition device 15. The ambient environment acquisition device 15 has, for example, detection means for detecting the weather, temperature, brightness, and / or time around the vehicle. The ambient environment acquisition device 15 can also have detection means for detecting information about the road surface on which the vehicle is traveling. The environment determination unit 22 can estimate whether the area around the vehicle is crowded with pedestrians and the like based on the environmental information around the vehicle input from the ambient environment acquisition device 15, and determine whether the environment around the vehicle is a specific environment, from the viewpoints that there are more people and traffic during the day than at night, more people and traffic on sunny days than on rainy days, more people and traffic in warm seasons than in cold seasons, and more people and traffic on clear roads than on icy roads.

[0034] The environment determination unit 22 may be configured to determine whether the vehicle's surrounding environment is a specific environment by combining the environmental information about the vehicle's surroundings input from the surrounding environment acquisition device 15 with the above-described cases (A) to (C). For example, even if a geographical area is not an urban area, if a major event is scheduled to be held at a certain time (season) of the year, the area is expected to be crowded with pedestrians, etc., and therefore, if the vehicle is in the area at that time, the environment determination unit 22 may determine that the vehicle's surrounding environment is not a specific environment even if the area is an urban area, from the viewpoint that drivers are expected to drive more carefully at night than during the day, or when the road surface is icy than when it is not icy.

[0035] The adjustment unit 23 is configured to adjust the collision mitigation brake control in accordance with the vehicle's surrounding environment determined by the environment determination unit 22. The collision mitigation brake control includes automatic brake control and warning control, and obstacles that may be present around the vehicle include four-wheeled vehicles, two-wheeled vehicles, bicycles, pedestrians, etc. If the vehicle's surrounding environment is a specific environment, the adjustment unit 23 sets the obstacle that is the target of the collision mitigation brake control to a first target obstacle and sets the function to first control. If the vehicle's surrounding environment is not a specific environment, the adjustment unit 23 sets the obstacle that is the target of the collision mitigation brake control to a second target obstacle and sets the function to second control.

[0036] The first target obstacle in the specific environment is, for example, a four-wheeled vehicle, and the first control is warning control. The second target obstacle outside the specific environment is, for example, a four-wheeled vehicle and a pedestrian, and the second control is warning control and automatic braking control. That is, in the specific environment, the target obstacles for the collision mitigation braking control are limited to four-wheeled vehicles, and the function is narrowed down to warning control, while outside the specific environment, pedestrians are added to the list of target obstacles for the collision mitigation braking control, and the function is expanded to include automatic braking control in addition to warning control.

[0037] This allows the target obstacle and function of the collision mitigation brake control to be switched according to the surrounding environment of the vehicle, and appropriate collision mitigation brake control can be executed according to the surrounding environment of the vehicle. Note that the adjustment of the collision mitigation brake control (switching of functions) can be set to enabled or disabled by, for example, operating a function selector switch by the user.

[0038] The flow of collision damage mitigation brake control in this embodiment will be described in detail below with reference to the flowchart of Fig. 2. The process shown in Fig. 2 is periodically executed by the control device 20.

[0039] First, in step S101, it is determined whether or not the function switching of the collision damage mitigation brake control has been enabled by operating the function switching switch included in the operation input device 14. If the function switching has been enabled, the process proceeds to step S102, and if it has been disabled, the process proceeds to step S104.

[0040] In step S102, the environment determination unit 22 acquires information for determining the vehicle's surrounding environment. Specifically, the environment determination unit 22 acquires information input from the obstacle detection device 10, the vehicle speed sensor 11, the positioning device 12, the map information database 13, and the surrounding environment acquisition device 15. In step S103, the environment determination unit 22 determines whether the vehicle's surrounding environment corresponds to the specific environment described above. If the vehicle's surrounding environment corresponds to the specific environment, the process proceeds to step S104, and if the vehicle's surrounding environment does not correspond to the specific environment, the process proceeds to step S111.

[0041] In step S104, the adjustment unit 23 sets the obstacle that is the target of the collision mitigation brake control as the first target obstacle and sets the function as the first control. The first target obstacle in the specific environment is, for example, a four-wheeled vehicle, and the first control is the warning control. The adjustment unit 23 can notify the driver of the target obstacle and function of the collision mitigation brake control that has been set, for example, by displaying it on the display device 50.

[0042] In step S105, the collision determination unit 21a calculates the collision prediction time TTC for the first target obstacle set in step S104, i.e., the four-wheeled vehicle ahead of the vehicle. In step S106, it is determined whether the collision prediction time TTC calculated in step S105 is equal to or less than a preset first predetermined value TTC1. If the collision prediction time TTC is equal to or less than the first predetermined value TTC1, the process proceeds to step S107, where the warning control unit 21b sends a command to the alarm device 40 to issue a warning. As a result, when the environment around the vehicle is a specific environment, warning control for the first target obstacle is executed as collision damage mitigation brake control. If the collision prediction time TTC is greater than the first predetermined value TTC1, this process ends.

[0043] Meanwhile, in step S111, the adjustment unit 23 sets the obstacle that is the target of the collision mitigation brake control as the second target obstacle and sets the function to the second control. The second target obstacle outside the specific environment is, for example, a four-wheeled vehicle or a pedestrian, and the second control is warning control and automatic brake control. The adjustment unit 23 can notify the driver of the target obstacle and function of the collision mitigation brake control that have been set, for example, by displaying them on the display device 50.

[0044] In step S112, the collision determination unit 21a calculates a collision prediction time TTC for the second target obstacles set in step S111, i.e., a four-wheeled vehicle and a pedestrian ahead of the vehicle. In step S113, it is determined whether the collision prediction time TTC calculated in step S112 is equal to or less than a second predetermined value TTC2 set in advance. If it is determined that the collision prediction time TTC is equal to or less than the second predetermined value TTC2, the process proceeds to step S114, where the brake control unit 21c controls the brake device 30 to generate a braking force equivalent to the maximum deceleration.

[0045] If it is determined in step S113 that the collision prediction time TTC calculated in step S112 is greater than the second predetermined value TTC2, the process proceeds to step S115, where it is determined whether the collision prediction time TTC is equal to or less than the first predetermined value TTC1. If the collision prediction time TTC is equal to or less than the first predetermined value TTC, the process proceeds to step S116, where the warning control unit 21b sends a command to the alarm device 40 to issue a warning. On the other hand, if the collision prediction time TTC is greater than the first predetermined value TTC1, this process ends. As a result, when the environment around the vehicle is outside the specific environment, automatic brake control and warning control are executed as collision damage mitigation brake control targeting the second target obstacle.

[0046] The vehicle control system 1 according to the present embodiment described above can achieve the following advantageous effects.

[0047] (1) The vehicle control system 1 includes a collision determination unit 21a that determines the possibility of a collision with a target obstacle present in front of the vehicle, a brake control unit 21c that controls the braking force to perform automatic brake control in accordance with the possibility of collision determined by the collision determination unit 21a, an environment determination unit 22 that determines the environment surrounding the vehicle, and an adjustment unit 23 that changes the type of target obstacle in the automatic brake control in accordance with the environment surrounding the vehicle determined by the environment determination unit 22.

[0048] The effects and impacts of executing collision mitigation braking control may differ between an environment where multiple types of obstacles, such as four-wheeled vehicles, motorcycles, and pedestrians, are present around the vehicle and an environment where there are fewer obstacles around the vehicle. For example, in an environment where multiple types of obstacles are present, collision mitigation braking control may be executed excessively, or automatic braking control may result in a rear-end collision with a following vehicle. Therefore, by changing the type of obstacle targeted by automatic braking control depending on the environment around the vehicle, it is possible to execute appropriate automatic braking control according to the environment.

[0049] (2) When the environment determination unit 22 determines that the environment around the vehicle is not a specific environment, the adjustment unit 23 is configured to increase the types of target obstacles. By changing the types of target obstacles depending on whether the environment around the vehicle is a specific environment or not, appropriate automatic brake control can be performed according to the surrounding environment.

[0050] (3) The environment determination unit 22 sets a predetermined geographical area as the specific environment. For example, by defining as the predetermined geographical area an area corresponding to an urban area or a busy street where there are many obstacles such as pedestrians and bicycles, or an area where drivers tend to drive closely to their vehicles, it is possible to narrow down the target obstacles in these areas and perform effective collision mitigation braking control. Outside the predetermined geographical area, the number of target obstacles increases, allowing the collision mitigation braking control to fully function.

[0051] (4) The environment determination unit 22 determines whether the environment around the vehicle is a specific environment based on the density of obstacles within a predetermined range around the vehicle. When there are many obstacles around the vehicle, for example, when the area around the vehicle is crowded with pedestrians, the environment determination unit 22 determines that the environment around the vehicle is a specific environment, thereby narrowing down the target obstacles and enabling effective collision mitigation brake control in such an environment. In an environment with a low density of obstacles, the number of target obstacles increases, allowing the collision mitigation brake control to fully function. Note that, when adjusting the collision mitigation brake control, the adjustment unit 23 may exclude obstacles determined to be present at a high density from the target obstacles and include obstacles determined to be present at a low density.

[0052] (5) The environment determination unit 22 determines whether the vehicle is in an urban area as the vehicle's surrounding environment, and the adjustment unit 23 sets four-wheeled vehicles as target obstacles (first target obstacles) when the vehicle is in an urban area, and sets four-wheeled vehicles and pedestrians as target obstacles (second target obstacles) when the vehicle is outside an urban area. Since it is believed that there are many pedestrians in urban areas, excluding pedestrians from the target obstacles in urban areas can prevent excessive execution of collision mitigation braking control or the execution of automatic braking control, which could lead to a rear-end collision with a following vehicle. By including pedestrians in the target obstacles outside urban areas, it is expected that the collision mitigation braking control will be able to fully function.

[0053] (6) The environment determination unit 22 determines that the surrounding environment of the vehicle is a specific environment when the execution of automatic braking control is likely to result in contact between the vehicle and a vehicle following the vehicle. When there is a possibility of contact between the vehicle and a vehicle following the vehicle, the type of target obstacles is reduced and the collision damage mitigation brake control is limited, thereby preventing the execution of automatic braking control from inducing a rear-end collision by the vehicle following the vehicle. When there is no possibility of contact between the vehicle and a vehicle following the vehicle, the type of target obstacles is increased, which is expected to fully demonstrate the function of the collision damage mitigation brake control.

[0054] (7) The adjustment unit 23 sets at least one type of obstacle as a target obstacle regardless of the surrounding environment of the vehicle. As a result, whether the surrounding environment of the vehicle is a specific environment or not, the collision damage mitigation brake control can be continuously executed to support the driver's driving operation.

[0055] (8) The environment determination unit 22 determines at least one of the time of day, season, and weather as the vehicle's surrounding environment. This allows adjustment to be made so that appropriate collision damage mitigation brake control is performed in accordance with the surrounding environment, taking into account various scenes in the vehicle's surrounding environment.

[0056] (9) The vehicle further includes a warning control unit 21b that performs warning control in accordance with the likelihood of a collision determined by the collision determination unit 21a, and the adjustment unit 23 is configured to switch between a first control that performs only warning control and a second control that performs warning control and automatic braking control in accordance with the vehicle's surrounding environment. This allows for appropriate collision mitigation brake control to be performed in accordance with the vehicle's surrounding environment. For example, the adjustment unit 23 can select the first control when the vehicle's surrounding environment is a specific environment, and select the second control when the vehicle's surrounding environment is not the specific environment. By limiting the function of the collision mitigation brake control to warning control in the specific environment, a situation in which a following vehicle would rear-end the vehicle can be prevented. However, by expanding the function of the collision mitigation brake control to warning control and automatic braking control outside the specific environment, the collision mitigation brake control function can be fully utilized.

[0057] -Second embodiment- A vehicle control system 1 according to a second embodiment of the present invention will be described below. The basic configuration of the vehicle control system 1 according to the second embodiment is the same as that of the first embodiment described above. The following mainly describes the differences from the first embodiment.

[0058] In the first embodiment described above, the vehicle's surrounding environment is determined to be a specific environment when it corresponds mainly to any one of the above-described cases (A) to (C). In the second embodiment, these cases (A) to (C) are combined to determine whether the vehicle's surrounding environment is a specific environment. The flow of the specific environment determination process in this embodiment will be described using the flowchart in FIG. 3. The determination process in FIG. 3 corresponds to the process in step S103 in the flowchart in FIG. 2 described above.

[0059] In step S301, the environment determination unit 22 determines whether or not information for determining the vehicle's surrounding environment was acquired in step S102 of the flowchart in Fig. 2. If information was successfully acquired from the obstacle detection device 10, the vehicle speed sensor 11, the positioning device 12, the map information database 13, the surrounding environment acquisition device 15, etc., the process proceeds to step S302. On the other hand, if it is determined that information for determining the vehicle's surrounding environment cannot be acquired, for example, if vehicle position information cannot be acquired due to a malfunction of the positioning device 12, the process proceeds to step S305.

[0060] In step S302, it is determined whether the current location of the vehicle is within an area such as an urban area or a shopping district. If the current location of the vehicle is within an area such as an urban area, the process proceeds to step S303. If the current location of the vehicle is outside an urban area, the process proceeds to step S306.

[0061] In step S303, it is determined whether the density of pedestrians within a predetermined range around the vehicle is higher than a predetermined value. If the density of pedestrians within the predetermined range is high, the process proceeds to step S304. If the density of pedestrians is equal to or lower than the predetermined value, the process proceeds to step S306.

[0062] In step S304, it is determined whether the predicted collision time TTC between the vehicle and the following vehicle is less than a preset value and whether there is a possibility that the vehicle and the following vehicle will collide due to the execution of automatic brake control. If there is a possibility that the vehicle and the following vehicle will collide, the process proceeds to step S305, and if there is no possibility that the vehicle and the following vehicle will collide, the process proceeds to step S306.

[0063] In step S305, the environment determination unit 22 determines that the environment around the vehicle is a specific environment. That is, the environment around the vehicle is determined to be a specific environment when the current location of the vehicle is in an area such as an urban area, the area around the vehicle is crowded with pedestrians, and there is a possibility of contact between the vehicle and a following vehicle. In this case, the process proceeds to step S104 in the flowchart of FIG. 2, where a first target obstacle is set as an obstacle that is the target of collision mitigation braking control, and the function is set to first control. As a result, the environment around the vehicle is strictly determined, and collision mitigation braking control is limited only in environments where it is considered that executing collision mitigation braking control may compromise the safety or reliability of the system.

[0064] If any of steps S302 to S304 is judged to be negative, then in step S306, it is judged that the environment surrounding the vehicle is outside the specific environment. For example, even if the current location of the vehicle is in an area such as an urban area, if the area around the vehicle is not crowded with pedestrians or if there is no possibility of contact with a following vehicle, it is judged to be outside the specific environment. In this case, the process proceeds to step S111 of the flowchart in FIG. 2, where a second target obstacle is set as an obstacle that is the target of the collision mitigation braking control, and the function is set to the second control. As a result, in an environment where it is considered unlikely that the safety or reliability of the system will be compromised by executing the collision mitigation braking control, the collision mitigation braking control can be expanded to fully demonstrate its function.

[0065] If step S301 is judged to be negative and information cannot be normally acquired from the obstacle detection device 10, the vehicle speed sensor 11, the positioning device 12, the map information database 13, the surrounding environment acquisition device 15, etc., it is judged in step S305 that the surrounding environment of the vehicle is a specific environment. As a result, a first target obstacle is set as an obstacle that is a target of collision mitigation braking control, the function is set to first control, and the target obstacles and functions of collision mitigation braking control are limited.

[0066] -Variations- (1) In the above-described embodiment, the target obstacle and function of the collision mitigation braking control are adjusted according to the vehicle's surrounding environment. However, this is not limited to this, and a configuration may be adopted in which only the target obstacle is adjusted without adjusting the function. For example, when the vehicle's surrounding environment is determined to be a specific environment, the target obstacle may be set as a first target obstacle, and warning control and automatic braking control may be executed for the first target obstacle. When the vehicle's surrounding environment is determined to be outside the specific environment, the target obstacle may be set as a second target obstacle, and warning control and automatic braking control may be executed for the second target obstacle. Alternatively, the collision mitigation braking control may be configured to execute only automatic braking control. In this case, when the vehicle's surrounding environment is determined to be a specific environment, the target obstacle may be set as a first target obstacle, and automatic braking control may be executed for the first target obstacle. When the vehicle's surrounding environment is determined to be outside the specific environment, the target obstacle may be set as a second target obstacle, and automatic braking control may be executed for the second target obstacle.

[0067] (2) In the above-described embodiment, the specific environment is, for example, an environment where multiple types of obstacles are densely packed, such as an urban area. However, this is not limited to this, and an area where only limited types of obstacles are expected to exist can also be specified as the specific environment. For example, on a highway, only four-wheeled vehicles or two-wheeled vehicles usually exist. Therefore, by setting the highway as the specific environment, a first target obstacle (e.g., a four-wheeled vehicle) can be set as an obstacle to be subjected to the collision mitigation braking control. By excluding pedestrians from the obstacles to be subjected to the collision mitigation braking control on a highway, it is possible to prevent malfunction of the control due to erroneous detection. In this case, regardless of whether the surrounding environment of the vehicle corresponds to a specific environment, the function of the collision mitigation braking control can be set to execute both warning control and automatic brake control, thereby effectively demonstrating the function of the collision mitigation braking control.

[0068] (3) In the above-described embodiment, the system is configured to reduce the number of target obstacles and limit the functions when the vehicle's surrounding environment is a specific environment, and to increase the number of target obstacles and expand the functions when the vehicle's surrounding environment is not a specific environment. However, the present invention is not limited to this. The system may be configured to reduce the number of target obstacles and limit the functions when the vehicle's surrounding environment is not a specific environment, and to increase the number of target obstacles and expand the functions when the vehicle's surrounding environment is a specific environment. In this case, for example, the vehicle's surrounding environment can be determined to be a specific environment when the vehicle's current location is in a suburban area rather than an urban area. Furthermore, the environmental information surrounding the vehicle used to determine whether the vehicle's surrounding environment is a specific environment is not limited to the information described above. In other words, in order to optimize the collision damage mitigation brake control function according to the vehicle's environment, it is possible to determine whether the vehicle's surrounding environment corresponds to a specific environment based on various information other than the above-described environmental information surrounding the vehicle.

[0069] (4) In the above-described embodiment, four-wheeled vehicles are set as the first target obstacles, and four-wheeled vehicles and pedestrians are set as the second target obstacles. However, this is not limited to this, and two-wheeled vehicles and / or bicycles may also be added as second target obstacles.

[0070] (5) In the above-described embodiment, the function switching of the collision mitigation braking control is switched between enabled and disabled by operating a function switching switch included in the operation input device 14. However, this is not limited to this, and the function switching of the collision mitigation braking control may be configured to be enabled without operating a function switching switch. Also, in the flowchart of FIG. 2 described above, when the function switching of the collision mitigation braking control is disabled, the function of the collision mitigation braking control is set to the first control and the target obstacle is set to the first target obstacle. However, this is not limited to this, and when the function switching of the collision mitigation braking control is disabled, the second control and the second target obstacle may be set.

[0071] Although several embodiments of the present invention have been described above, it should be noted that the present invention is not limited to the above-described embodiments, and various modifications and variations are possible within the scope of the present invention. [Explanation of symbols]

[0072] 1 Vehicle control system 10 Obstacle detection device 11 Vehicle speed sensor 12 Positioning equipment 20 Control device 21 AEB control unit, 21a collision determination unit, 21b warning control unit, 21c brake control unit 22 Environmental Judgment Department 23 Adjustment part 30 Brake device 40 Alarm device 50 Display device

Claims

1. a collision determination unit that determines the possibility of a collision with a target obstacle present in front of the vehicle; a brake control unit that controls a braking force so as to perform automatic brake control in accordance with the possibility of a collision determined by the collision determination unit; an environment determination unit that determines a surrounding environment of the vehicle; an adjustment unit that changes the type of the target obstacle in the automatic brake control in accordance with the surrounding environment of the vehicle determined by the environment determination unit; A vehicle control system comprising:

2. The vehicle control system according to claim 1 , wherein the adjustment unit is configured to increase the types of the target obstacles when the environment determination unit determines that the surrounding environment of the vehicle is not a specific environment.

3. The vehicle control system according to claim 2 , wherein the environment determination unit sets a predetermined geographical area as the specific environment.

4. The vehicle control system according to claim 2 , wherein the environment determination unit determines whether the surrounding environment of the vehicle is the specific environment based on a density of obstacles within a predetermined range around the vehicle.

5. the environment determination unit determines whether the vehicle is in an urban area as a surrounding environment of the vehicle; 2. The vehicle control system according to claim 1, wherein the adjustment unit sets a four-wheeled vehicle as the target obstacle when the vehicle is in an urban area, and sets a four-wheeled vehicle and a pedestrian as the target obstacle when the vehicle is outside an urban area.

6. 3. The vehicle control system of claim 2, wherein the environment determination unit determines that the surrounding environment of the vehicle is the specific environment when there is a possibility that the vehicle will come into contact with a vehicle following the vehicle due to the execution of the automatic brake control.

7. The vehicle control system according to claim 1 , wherein the adjustment unit sets at least one type of obstacle as the target obstacle regardless of the surrounding environment of the vehicle.

8. The vehicle control system according to claim 1 , wherein the environment determination unit determines at least one of a time of day, a season, and weather as the surrounding environment of the vehicle.

9. a warning control unit that performs warning control in accordance with the possibility of collision determined by the collision determination unit, 9. The vehicle control system according to claim 1, wherein the adjustment unit is configured to switch between a first control that performs only the warning control and a second control that performs the warning control and the automatic brake control, depending on the surrounding environment of the vehicle.

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