Control system for vehicle

Abstract

To properly execute, in a control system for a vehicle, an ACC function even when a road sign for prompting a driver to decelerate to a predetermined speed is provided.SOLUTION: A control system for vehicle includes: a sign recognition unit configured to recognize a road sign that prompts a driver to reduce a vehicle speed to a predetermined speed; a vehicle speed adjustment unit configured to execute vehicle speed adjustment control to decelerate the vehicle speed V of the vehicle to a minimum speed when the road sign is recognized in a case where an ACC function is executed. The vehicle speed adjustment unit is configured to: permit an increase in the vehicle speed according to an operation of an accelerator pedal when the accelerator pedal is operated by the driver during the vehicle speed adjustment control; terminate the vehicle speed adjustment control when the vehicle speed according to the operation of the accelerator pedal during the vehicle speed adjustment control exceeds a first speed that is higher than the minimum speed; and continue the operation of the vehicle speed adjustment control when the accelerator pedal is operated during the vehicle speed adjustment control and then the vehicle speed when the accelerator pedal is released is equal to or lower than the first speed.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle control system configured to perform adaptive cruise control functions. [Background technology]

[0002] To assist a driver in driving, an adaptive cruise control (ACC) function is known that controls the distance between vehicles so that the vehicle maintains an appropriate distance between the vehicles. When the ACC function is running, the vehicle's acceleration and deceleration are controlled to follow the vehicle ahead while maintaining a set distance between the vehicles. If there is no vehicle ahead, the vehicle is controlled to travel at a set speed. Regarding the ACC function, for example, Patent Document 1 discloses a device configured not to accelerate the vehicle when the surrounding conditions of the vehicle satisfy predetermined conditions while the ACC function is running. The device described in Patent Document 1 is configured to decelerate the vehicle without accelerating when the tail end of a traffic jam, a railroad crossing, or a stop sign is within a predetermined distance ahead of the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-86580 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, roads are sometimes equipped with road signs that prompt vehicles to decelerate to a predetermined speed as a traffic safety measure. When the ACC function automatically decelerates the vehicle in response to the road sign, if the vehicle speed differs from the driver's intended speed, the driver may operate the accelerator pedal and accelerate the vehicle. In such cases, the deceleration control by the ACC function and the driver's accelerator pedal operation may coexist, resulting in undesired fluctuations in vehicle speed. On the other hand, if the system is set to not permit the driver to operate the accelerator pedal, the driver's intention to accelerate cannot be reflected, reducing the convenience of the ACC function.

[0005] The present invention was made in consideration of the above-described circumstances, and its purpose is to enable the ACC function to be executed appropriately even when road signs are posted urging the driver to slow down to a predetermined speed. [Means for solving the problem]

[0006] According to one aspect of the present invention, a vehicle control system is configured to execute an ACC function that performs constant speed driving according to a set vehicle speed when there is no preceding vehicle in the lane in which the vehicle is traveling, and performs following driving while maintaining a set inter-vehicle distance when there is a preceding vehicle. The system includes: a sign recognition unit configured to recognize road signs that prompt the vehicle to slow down to a predetermined speed; and a vehicle speed adjustment unit configured to execute vehicle speed adjustment control to slow down the vehicle speed to a minimum speed when the road sign is recognized by the sign recognition unit while the ACC function is being executed. The vehicle speed adjustment unit is configured to allow the vehicle speed to increase in response to the operation of the accelerator pedal when the accelerator pedal is operated by the driver during the vehicle speed adjustment control, to terminate the vehicle speed adjustment control when the vehicle speed in response to the operation of the accelerator pedal during the vehicle speed adjustment control exceeds a first speed that is greater than the minimum speed, and to continue operation of the vehicle speed adjustment control if the accelerator pedal is operated during the vehicle speed adjustment control and the vehicle speed when the accelerator pedal is subsequently released is equal to or less than the first speed. [Effects of the Invention]

[0007] The vehicle control system according to the present invention can properly execute the ACC function even when road signs are installed urging the driver to slow down to a predetermined speed. [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 an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the control mode and the change in vehicle speed over time when vehicle speed adjustment control is executed. [Figure 3] FIG. 3 is a flowchart illustrating the flow of the vehicle speed adjustment control. DETAILED DESCRIPTION OF THE INVENTION

[0009] A vehicle control system according to an embodiment of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a block diagram showing a schematic configuration of a vehicle control system 1 according to this embodiment. The vehicle control system 1 according to this embodiment is configured to perform an ACC function in which, when there is no preceding vehicle in the lane in which the vehicle is traveling, the vehicle travels at a constant speed according to a set vehicle speed, and, when there is a preceding vehicle in the lane, the vehicle travels while maintaining a set inter-vehicle distance.

[0010] 1, the control system 1 includes a control device 20. The control system 1 may also optionally include an imaging device 11, an obstacle detection device 12, a vehicle speed sensor 13 that detects the vehicle speed, an operation input device 14, a notification device 30, a braking device 40, and a drive device 50.

[0011] The imaging device 11 is configured to capture an image of the area ahead of the vehicle. The imaging device 11 is configured as a digital camera having an imaging element such as a CCD or CMOS, and is configured to output information of the area ahead of the vehicle as a still image and / or a video. The image data of the area ahead captured by the imaging device 11 is input to the control device 20.

[0012] The obstacle detection device 12 is configured to detect an obstacle (e.g., a preceding vehicle) ahead of the vehicle and measure the relative distance (inter-vehicle distance) between the vehicle and the obstacle. For example, a millimeter-wave radar, a sonar sensor, or a LiDAR (Light Detection and Ranging) can be used as the obstacle detection device 12. The distance measurement by the obstacle detection device 12 is dynamically performed at a predetermined measurement period. The obstacles detected by the obstacle detection device 12 include road signs indicating the presence of a convex structure, which will be described later. The distance between the vehicle and the obstacle detected by the obstacle detection device 12 is input to the control device 20.

[0013] The operation input device 14 is configured to accept various operation inputs to the control device 20 by a user, for example, a driver. The operation input device 14 has, for example, an ACC switch operated by the driver to switch the ACC function on and off, a vehicle speed setting switch for setting the vehicle speed in the ACC function, a distance setting switch for setting the inter-vehicle distance in the ACC function, a deceleration request switch operated by the driver to request deceleration in vehicle speed adjustment control described later, and a reset switch operated by the driver to return the ACC function to normal operation during vehicle speed adjustment control. The operation input device 14 may be configured as, for example, a touch panel integrated with the display of a notification device 30 described later. Furthermore, the operation input device 14 may be configured so that multiple functions are assigned to one switch.

[0014] 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 ACC control unit 21, a sign recognition unit 22, a vehicle speed adjustment unit 23, a notification unit 24, etc., and to control the entire vehicle control system 1. Details of the control by the control device 20 will be described later.

[0015] The notification device 30 is configured to notify the vehicle occupants in response to commands from the control device 20. The notification device 30 has, for example, a liquid crystal display, indicator lights, a speaker, etc. arranged on the instrument panel at the front of the vehicle, and can provide information to the occupants visually and / or audibly.

[0016] The braking device 40 is a braking device that generates braking force according to the amount of depression of the brake pedal (not shown) by the driver, and is equipped with a brake controller and a brake actuator for generating braking force according to a braking command from the vehicle system or the control device 20.

[0017] The drive unit 50 is configured to generate a drive force for running the vehicle, and includes an engine controller (not shown) that controls the drive force in accordance with the amount of depression of an accelerator pedal (not shown) by the driver or in accordance with a control command from the control device 20. Note that the drive unit 50 of the vehicle may be, for example, an internal combustion engine, a motor, or the like.

[0018] Next, the control in the control device 20 will be described in detail. The control device 20 is configured to execute the ACC function using the ACC control unit 21 based on image data of the area ahead of the vehicle input from the imaging device 11 and the inter-vehicle distance from an obstacle input from the obstacle detection device 12. Specifically, when the ACC function is on and there is no preceding vehicle in the lane in which the vehicle is traveling, the ACC control unit 21 controls the braking device 40 and the drive unit 50 to travel at a constant speed in accordance with a set vehicle speed (target vehicle speed) input from the operation input device 14. Furthermore, when the ACC function is on and there is a preceding vehicle in the lane in which the vehicle is traveling, the ACC control unit 21 controls the braking device 40 and the drive unit 50 to follow the preceding vehicle while maintaining the set inter-vehicle distance input from the operation input device 14.

[0019] The ACC function is configured to operate within a predetermined vehicle speed range (for example, approximately 30 km / h to approximately 100 km / h). The ACC function is also configured to temporarily stop operation when the accelerator pedal is operated, and to stop operation when the brake pedal is operated.

[0020] Here, road signs are sometimes installed on roads to encourage vehicles to slow down to a predetermined speed (recommended speed) as a traffic safety measure. Road signs to encourage vehicles to slow down to a predetermined speed include slow down signs to encourage vehicles to slow down and stop signs to encourage vehicles to stop, but here we particularly focus on road signs that are installed in combination with physical devices installed on the road to encourage vehicles to slow down to a predetermined speed that is greater than 0 km / h.

[0021] An example of a physical device installed on a road to encourage vehicles to slow down to a predetermined speed is a convex structure installed on the road surface. The convex structure is a raised portion of the road surface that causes up and down vibrations on passing vehicles, thereby encouraging drivers who see it to slow down. Such convex structures are also called speed breakers, speed bumps, humps, etc., and are installed with the purpose of limiting vehicle speeds to, for example, approximately 40 km / h or less, approximately 30 km / h or less, or approximately 25 km / h or less.

[0022] A road sign (caution sign) indicating that a convex structure is installed on the road is installed a predetermined distance before the convex structure. This road sign indicates the presence of a convex structure that urges drivers to slow down to a predetermined speed. The distance from the road sign to the convex structure varies depending on the type of convex structure and the regulations of the country or region where the convex structure is installed, but is, for example, approximately 30 to 50 meters. When a driver drives the vehicle themselves, when the driver sees the road sign, they recognize that there is a speed breaker ahead and operate the brake pedal to slow down, drive over the speed breaker while maintaining a low vehicle speed, and after passing the speed breaker, they operate the accelerator pedal to accelerate.

[0023] If the ACC function is not configured to decelerate in response to a convex structure, a vehicle traveling at a constant speed using the ACC function will pass over the convex structure at the set vehicle speed. Also, when following a vehicle using the ACC function, if the preceding vehicle decelerates to pass over the convex structure, the vehicle will also decelerate. However, if the preceding vehicle accelerates after passing the convex structure, the vehicle will also accelerate and pass over the convex structure in an accelerated state. Thus, passing over a convex structure while the ACC function is operating at the set vehicle speed or following the preceding vehicle may cause discomfort to passengers or may cause unnecessary damage to the vehicle body or cargo.

[0024] Consider the case of a speed breaker installed as an example of a convex structure. Speed ​​breakers have been introduced in India, for example, as a traffic safety measure, and are installed to encourage vehicles to keep their speed below a certain limit. The recommended speed for passing through a speed breaker is approximately 25 km / h. However, because speed breakers protrude significantly from the road surface, in actual traffic flow, many drivers slow down to approximately 10 km / h, which is roughly equivalent to a creeping phenomenon, and pass through the speed breaker.

[0025] Considering this situation, even if the vehicle decelerates to the lower limit (e.g., about 30 km / h) within the ACC function's specified vehicle speed range (e.g., about 30 km / h to about 100 km / h) in response to a speed breaker, it may not be possible to sufficiently reduce the shock when going over the speed breaker. On the other hand, if the driver operates the brake pedal before the speed breaker every time they see a road sign in order to decelerate in response to a road sign, the ACC function is canceled, reducing the convenience of the ACC function.

[0026] Therefore, the vehicle control system 1 in this embodiment is configured to adjust the ACC function so that it can be executed appropriately even when a road sign is installed urging the driver to slow down to a predetermined speed. Therefore, the control device 20 further includes a sign recognition unit 22, a vehicle speed adjustment unit 23, and a notification unit 24. In the following, an example will be described in which a speed breaker is installed as the convex structure to urge the driver to keep the vehicle speed to approximately 25 km / h or less, and a road sign indicating that a speed breaker is installed is recognized as the road sign.

[0027] The sign recognition unit 22 is configured to recognize road signs that are installed ahead of the vehicle in the direction of travel on the road in which the vehicle is traveling and that urge the vehicle to slow down to a predetermined speed, based on image data of the area ahead of the vehicle input from the imaging device 11. Specifically, the sign recognition unit 22 recognizes road signs that indicate that speed breakers that urge the vehicle to slow down are installed on the road surface. Furthermore, the sign recognition unit 22 can recognize the distance to the recognized road sign based on information on the distance to the obstacle input from the obstacle detection device 12.

[0028] The vehicle speed adjustment unit 23 is configured to execute vehicle speed adjustment control that adjusts the vehicle speed while maintaining the ACC function when a road sign is recognized by the sign recognition unit 22 while the ACC function is being executed. Specifically, the vehicle speed adjustment control executed by the vehicle speed adjustment unit 23 includes a first control that decelerates the vehicle speed to a first speed when a road sign is recognized by the sign recognition unit 22, and a second control that decelerates the vehicle speed to a second speed lower than the first speed in response to a deceleration request by the driver while the first control is being executed. In other words, the vehicle speed adjustment control is configured to decelerate the vehicle speed in two stages to pass a speed breaker.

[0029] The notification unit 24 is configured to notify the driver via the alarm device 30 that the vehicle speed adjustment unit 23 is executing vehicle speed adjustment control. The notification to the driver can be, for example, by displaying a mark representing a speed breaker on a display or by emitting a buzzer sound.

[0030] Next, details of the vehicle speed adjustment control will be explained with reference to FIG. 2. FIG. 2 shows an example of the control mode and the change in vehicle speed V over time from when road sign A indicating the presence of a speed breaker is recognized until vehicle C passes speed breaker B. The control mode of the ACC function at time t0 is constant speed traveling mode. The control mode of the ACC function switches from constant speed traveling mode to first control mode, second control mode, and low speed holding mode in that order, and returns to constant speed traveling mode after passing over speed breaker B. During the period shown in FIG. 2, the ACC function remains on, and the first control mode, second control mode, and low speed holding mode are vehicle speed adjustment control modes. In the example of FIG. 2, road sign A indicating that speed breaker B is installed is installed a predetermined distance (e.g., approximately 40 m) before speed breaker B.

[0031] (1) First control mode At time t1, when the first control condition is met, the control mode of the ACC function switches from the constant speed traveling mode to the first control mode. That is, vehicle speed adjustment control is initiated to adjust the vehicle speed in response to speed breaker B. At this time, the notification device 30 notifies the occupants of vehicle C that the vehicle speed adjustment control will be executed. For example, the notification device 30 displays a mark indicating that the vehicle speed adjustment control will be executed. In addition to or instead of displaying the mark, the notification device 30 may emit a buzzer sound to notify the occupants that the first control of the vehicle speed adjustment control will be started.

[0032] The vehicle speed adjustment unit 23 determines that the first control condition is met when all of the following conditions (a) to (d) are met. (a) Road sign A indicating that speed breaker B is installed is recognized. (b) The ACC function is in operation. (c) The vehicle speed V is equal to or less than the upper threshold Vt. (d) The vehicle is traveling straight.

[0033] (a) Road sign A indicating that speed breaker B is installed is recognized. The sign recognition unit 22 recognizes road sign A installed ahead of the vehicle C based on image data input from the imaging device 11 and information on the distance to the obstacle input from the obstacle detection device 12. When road sign A is recognized, the sign recognition unit 22 also recognizes the distance to road sign A. In the example shown in FIG. 2 , the distance from vehicle C to road sign A at time t1 when road sign A is recognized by the sign recognition unit 22 is approximately 30 m. Note that this distance may vary depending on the detection performance of the imaging device 11 and the obstacle detection device 12, the presence or absence of an obstacle that obstructs the visibility of road sign A, etc.

[0034] (b) The ACC function is in operation. Although FIG. 2 shows an example of the constant speed running mode, the ACC function is also determined to be operating in the case of the following running mode of the ACC function.

[0035] (c) The vehicle speed V is equal to or less than the upper threshold Vt. When the vehicle speed V is in a high vehicle speed range exceeding the upper limit threshold Vt, the vehicle speed adjustment control including the first control and the second control may not be able to sufficiently decelerate the vehicle before reaching the speed breaker B, and there is also a possibility that road sign A may be erroneously detected. If road sign A is erroneously detected, there is a high risk of being hit from behind by a following vehicle traveling behind the vehicle C due to deceleration by the vehicle speed adjustment control. Therefore, when the vehicle speed V detected by the vehicle speed sensor 13 is in a high vehicle speed range exceeding the upper limit threshold Vt (for example, approximately 60 km), the vehicle speed adjustment control is not started.

[0036] (d) The vehicle is traveling straight. Speed ​​breaker B is basically installed on a straight road, and if road sign A is recognized while vehicle C is traveling on a curve, there is a possibility that the detection is erroneous. In addition, if vehicle C slows down due to vehicle speed adjustment control while traveling on a curve, this may affect the maneuverability of vehicle C. Therefore, vehicle speed adjustment control is not executed while vehicle C is traveling on a curve. Whether vehicle C is traveling straight or not can be determined based on a signal from a steering angle sensor (not shown), the current position of vehicle C, map information from a map information database, etc.

[0037] When the vehicle speed adjustment unit 23 determines that the first control condition is met, it starts vehicle speed adjustment control to adjust the vehicle speed V in accordance with the speed breaker B. The control mode of the ACC function switches from the constant speed traveling mode to the first control mode, and the vehicle speed adjustment unit 23 executes the first control to decelerate the vehicle speed V to a first speed V1. The first speed V1 can be, for example, a lower limit speed that can be set in the ACC function (e.g., approximately 30 km / h). The first speed V1 is preferably higher than the predetermined speed (approximately 25 km / h) at which deceleration is promoted by the speed breaker B. The vehicle speed adjustment unit 23 sends a command to the braking device 40 to decelerate to the first speed V1 at a first deceleration a1 that is set to an appropriate value in advance. As a result, the vehicle speed V automatically decreases from the set vehicle speed V0 to the first speed V1 at the first deceleration a1.

[0038] The first deceleration a1 may be a fixed value or a variable value. When the first deceleration a1 is set to be variable, it can be set, for example, based on the distance from the vehicle C to the road sign A when the road sign A is recognized by the sign recognition unit 22. The shorter the distance between the vehicle C and the road sign A, the larger the first deceleration a1 can be set. The distance from the vehicle C to the road sign A when the road sign A is recognized can vary depending on the detection performance of the imaging device 11 and the obstacle detection device 12, the presence or absence of an obstacle that obstructs the visibility of the road sign A, and other factors. Therefore, by setting the first deceleration a1 to be larger when the distance between the vehicle C and the road sign A is shorter, it becomes possible to sufficiently decelerate the vehicle speed V before reaching the speed breaker B.

[0039] If the driver operates the accelerator pedal while the first control is being executed, the vehicle speed adjustment unit 23 prioritizes the driver's intention to accelerate and permits an increase in the vehicle speed V in response to the accelerator pedal operation. That is, if the accelerator pedal is operated in the first control mode in which the vehicle speed is greater than the first speed V1 (when the termination condition, described later, is met), the vehicle speed adjustment control ends and the ACC function returns to normal operation. As described above, the ACC function is temporarily deactivated while the accelerator pedal is operated. When the driver releases the accelerator pedal, the ACC function resumes operation and the vehicle speed accelerates to the set vehicle speed V0 of the ACC function. In this case, to prevent the vehicle speed from unnecessarily accelerating before the speed breaker B, the acceleration required to accelerate to the set vehicle speed V0 may be set to a value smaller than the acceleration required for normal operation of the ACC function. This prevents the vehicle from unnecessarily accelerating before passing the speed breaker B.

[0040] Furthermore, if there is a preceding vehicle ahead of vehicle C, it is conceivable that the preceding vehicle will significantly decelerate in order to overcome speed breaker B. Therefore, when there is a preceding vehicle, vehicle C may be configured to decelerate at a deceleration rate greater than the first deceleration rate a1 in order to avoid the risk of colliding with the preceding vehicle that is decelerating. The deceleration rate in this case may be, for example, the maximum deceleration rate provided by the ACC function.

[0041] (2) Second control mode At time t2, when the second control condition is met, the control mode of the ACC function switches from the first control mode to the second control mode. The vehicle speed adjustment unit 23 determines that the second control condition is met when the following conditions (e) and (f) are met. At this time, the notification device 30 notifies the occupants of the vehicle C that the second control of the vehicle speed adjustment control will be executed. For example, the notification device 30 continues to display the mark that was displayed in the first control mode. In addition to or instead of displaying the mark, the notification device 30 may emit a buzzer sound to notify the occupants that the second control of the vehicle speed adjustment control will be started. (e) The first control condition is met. (f) The driver requests deceleration.

[0042] (e) The first control condition is met. The vehicle speed adjusting unit 23 permits a transition to the second control mode only when the first control mode is being executed.

[0043] (f) The driver requests deceleration. The speed breaker B is a convex portion installed on the road surface, and it is difficult to detect the presence of the speed breaker B using the imaging device 11 and the obstacle detection device 12 and accurately determine the distance from the vehicle C to the speed breaker B. Therefore, the vehicle speed adjustment unit 23 cannot determine the optimal deceleration timing based on the information input from the imaging device 11 and the obstacle detection device 12. Therefore, the vehicle speed adjustment unit 23 determines the deceleration timing based on a deceleration request from the driver who visually recognizes the speed breaker B. The deceleration request from the driver can be determined, for example, based on the operation of a deceleration request switch on the operation input device 14. While the vehicle speed V is being decelerated by the first control, the driver can determine the deceleration timing by operating the deceleration request switch on the operation input device 14 at the desired timing.

[0044] When the vehicle speed adjustment unit 23 determines that the second control condition is met, the control mode of the ACC function switches from the first control mode to the second control mode. The vehicle speed adjustment unit 23 executes second control to decelerate the vehicle speed V to a second speed V2 that is lower than the first speed V1. The second speed V2 is preferably a low vehicle speed that is equal to or lower than the predetermined speed (approximately 25 km / h) at which deceleration is promoted by the speed breaker B and is appropriate for the vehicle to safely cross the speed breaker B. For example, taking into account the vehicle speed when a driver passes through the speed breaker B in actual traffic flow, the second speed V2 can be set to, for example, approximately 10 km / h, which is a creeping level. The vehicle speed adjustment unit 23 sends a command to the braking device 40 to decelerate the vehicle to the second speed V2 at a second deceleration rate a2 that is set to an appropriate value in advance. As a result, the vehicle speed V is automatically further reduced from the first speed V1 to the second speed V2 at the second deceleration rate a2.

[0045] Here, the second deceleration a2 is set to a value greater than the first deceleration a1 (a2>a1). Even if the first deceleration a1 is variable as described above, a2>a1. The first control described above is automatically initiated when the road sign A is recognized by the sign recognition unit 22, so the first deceleration a1 is set to a small value so as to gently decelerate the vehicle C without placing an excessive burden on the driver. On the other hand, the second control is initiated by operation of the deceleration operation switch, which reflects the driver's intention to decelerate, so the second deceleration a2 is set to a large value so as to sufficiently decelerate the vehicle C before the speed breaker B. The first deceleration a1 and the second deceleration a2 are each set to appropriate values ​​based on test data, etc. By setting the first deceleration a1 and the second deceleration a2 in this manner, the vehicle can be decelerated gently when moving away from the speed breaker B (first control mode) and can be decelerated sufficiently greatly when approaching the speed breaker B (second control mode), thereby improving the vehicle's ability to traverse the speed breaker B.

[0046] If the driver operates the accelerator pedal while the second control is being executed, the vehicle speed adjustment unit 23 prioritizes the driver's intention to accelerate and permits an increase in the vehicle speed V in response to the accelerator pedal operation. If the accelerator pedal is operated in the second control mode in which the vehicle speed V is smaller than the first speed V1 and the vehicle speed V increases to exceed the first speed V1 (when an end condition, described later, is met), the vehicle speed adjustment control ends and the ACC function returns to normal operation. However, if the vehicle speed when the driver releases the accelerator pedal is equal to or lower than the first speed V1, the vehicle speed adjustment unit 23 continues to operate the vehicle speed adjustment control.

[0047] When the vehicle speed adjustment control operation is continued after the accelerator pedal is operated, the vehicle speed adjustment unit 23 decelerates the vehicle speed V to a second speed V2. That is, deceleration resumes when the driver releases the accelerator pedal. The deceleration here can be, for example, the second deceleration a2 described above. Alternatively, the vehicle speed adjustment unit 23 may maintain the vehicle speed V at the speed (<first speed V1) when the accelerator pedal is released.

[0048] (3) Low speed hold mode When the vehicle speed V drops to the second speed V2 at time t3, the control mode of the ACC function switches from the second control mode to the low speed holding mode. The vehicle speed adjustment unit 23 maintains the second speed V2 so that the vehicle C can safely overcome the speed breaker B at a low speed. The low speed holding mode can also be considered to be part of the second control mode.

[0049] If the driver operates the accelerator pedal while the low-speed holding mode is in progress, the vehicle speed adjustment unit 23 prioritizes the driver's intention to accelerate and permits an increase in the vehicle speed V in response to the accelerator pedal operation. If the accelerator pedal is operated in the low-speed holding mode in which the vehicle speed V is lower than the first speed V1 and the vehicle speed V increases to exceed the first speed V1 (when the termination condition, described later, is met), the vehicle speed adjustment control ends and the ACC function returns to normal operation. However, if the vehicle speed V when the driver releases the accelerator pedal is equal to or lower than the first speed V1, the vehicle speed adjustment unit 23 continues to operate the vehicle speed adjustment control. That is, from the point in time when the driver releases the accelerator pedal, the vehicle speed is decelerated to the second speed V2 and maintained at the second speed V2.

[0050] (4) Constant speed driving mode After vehicle C crosses over speed breaker B, when a predetermined termination condition is met at time t4, the control mode of the ACC function switches from low-speed maintenance mode to constant-speed driving mode. In other words, vehicle speed adjustment control ends, and the normal operation of the ACC function is restored. At this time, the mark displayed on the notification device 30 indicating that vehicle speed adjustment control is being executed is erased.

[0051] The predetermined termination conditions include the following conditions (g) to (i), and the vehicle speed adjustment unit 23 determines that the termination conditions are met when any one of the following conditions (g) to (i) is met. (g) The specified distance (end determination distance) has been traveled since the recognition of road sign A. (h) The driver must operate a switch to request the return of the ACC function. (i) The driver's operation of the accelerator pedal causes the vehicle to accelerate above a predetermined speed.

[0052] (g) The specified distance (end determination distance) has been traveled since the recognition of road sign A. After crossing over speed breaker B, there is no need to maintain the second speed V2, which is the low vehicle speed required to cross over speed breaker B. Therefore, it is desirable to promptly terminate vehicle speed adjustment control when a predetermined distance has been traveled since road sign A was recognized, i.e., since vehicle speed adjustment control was initiated, at which it can be determined that speed breaker B has been crossed. The distance from road sign A to speed breaker B is usually set to a predetermined specified distance (e.g., approximately 40 m). The distance from vehicle C's position to speed breaker B at time t1 when vehicle speed adjustment control was initiated can be estimated by adding the distance from vehicle C to road sign A (e.g., approximately 30 m) at time t1 when road sign A was recognized and vehicle speed adjustment control was initiated to the specified distance from road sign A to speed breaker B.

[0053] Therefore, the vehicle speed adjustment unit 23 sets an end determination distance based on the distance from the position of the vehicle C at time t1 when the road sign A was recognized to the speed breaker B, and determines that the end condition is met when it is determined that the vehicle C has traveled the end determination distance from the position of the vehicle C at time t1 when the road sign A was recognized. This ends the vehicle speed adjustment control and returns to the normal operation mode of the ACC function, and the vehicle C accelerates to the set vehicle speed V0 before the start of the vehicle speed adjustment control and travels in the constant speed traveling mode or the follow-up traveling mode.

[0054] (h) The driver must operate a switch to request the return of the ACC function. The reset switch of the operation input device 14 is a switch that is operated to return the ACC function to a normal operating mode (constant speed traveling mode or follow-up traveling mode). Operation of the reset switch can be understood as the driver's intention to return the ACC function to the normal mode or to accelerate. If the driver operates the reset switch of the operation input device 14 during vehicle speed adjustment control, it is considered that the driver intends to accelerate from the state decelerated by the vehicle speed adjustment control and return to the constant speed traveling mode or follow-up traveling mode of the ACC function.

[0055] Therefore, when it is detected that the reset switch of the operation input device 14 has been operated, the vehicle speed adjustment unit 23 determines that the termination condition has been met and terminates the vehicle speed adjustment control to prioritize the driver's intention. In this case, the control mode of the ACC function returns to the constant speed traveling mode or follow-up traveling mode at the set vehicle speed V0 before the start of the vehicle speed adjustment control. Note that, in any of the first control mode, second control mode, and low speed hold mode, when the reset switch is operated, the vehicle speed adjustment unit 23 can determine that the termination condition has been met and terminate the vehicle speed adjustment control.

[0056] (i) The driver's operation of the accelerator pedal causes the vehicle to accelerate above a predetermined speed. Since the speed breaker B is installed to limit the vehicle speed V to approximately 25 km / h or less, if the accelerator pedal is operated during vehicle speed adjustment control to accelerate to a predetermined speed exceeding 25 km / h, it can be understood that the driver intends to accelerate. Therefore, if the vehicle speed V detected by the vehicle speed sensor 13 is equal to or greater than the predetermined speed, the vehicle speed adjustment unit 23 determines that the termination condition is met and terminates the vehicle speed adjustment control to prioritize the driver's intention. In this case, the control mode of the ACC function returns to the constant speed cruising mode or follow-up cruising mode at the set vehicle speed V0 before the start of the vehicle speed adjustment control. Note that in any of the first control mode, second control mode, and low-speed hold mode, the vehicle speed adjustment unit 23 can determine that the termination condition is met and terminate the vehicle adjustment control if the vehicle speed V increases to or greater than the predetermined speed.

[0057] Here, the predetermined speed for determining whether or not the driver intends to accelerate is a value greater than the recommended speed for passing through a speed breaker (e.g., 25 km / h), and can be, for example, the lowest speed that can be set in the ACC function (e.g., approximately 30 km / h). In this case, the predetermined speed for determining whether or not the driver intends to accelerate is the same value as the first speed V1. For example, in the low-speed holding mode in which the second speed V2 is maintained, if the accelerator pedal is operated and the vehicle speed accelerates to or above the first speed V1, the vehicle adjustment control ends. This allows the driver's intention to accelerate to take priority, and makes it possible to quickly end the vehicle adjustment control and return to normal control of the ACC function, for example, when the sign recognition unit 22 erroneously detects road sign A.

[0058] When the vehicle speed adjustment unit 23 determines that the termination condition is met, the vehicle speed adjustment control ends and the ACC function returns to its normal operating mode, and the vehicle C gradually accelerates to the set vehicle speed V0 before the start of the vehicle speed adjustment control and travels in the constant speed traveling mode or the follow-up traveling mode.

[0059] The flow of vehicle speed adjustment control executed in response to a speed breaker while the ACC function is operating in this embodiment will be described below with reference to the flowchart in Fig. 3. Fig. 3 shows an example of the processing of vehicle speed adjustment control, which is periodically executed by the control device 20.

[0060] In step S101, the vehicle speed adjustment unit 23 determines whether or not the sign recognition unit 22 has recognized road sign A indicating that a speed breaker B is installed. The sign recognition unit 22 recognizes road sign A installed ahead in the direction of travel of the road on which the vehicle is traveling, based on image data of the area ahead of the vehicle input from the imaging device 11 and information input from the obstacle detection device 12. If road sign A is recognized, the sign recognition unit 22 also recognizes the distance between the recognized road sign A and the vehicle. If road sign A is recognized by the sign recognition unit 22, the process proceeds to step S102; if road sign A is not recognized, the process ends.

[0061] In step S102, the vehicle speed adjustment unit 23 determines whether the ACC function is operating. If the ACC function is turned on by the ACC switch of the operation input device 14 and the operation of the ACC function has not been temporarily stopped by operating the accelerator pedal or the like, it is determined that the ACC function is operating, and the process proceeds to step S103. If the ACC function is not operating, this process ends.

[0062] In step S103, vehicle speed adjustment unit 23 determines whether the above-mentioned first control condition is met. Specifically, it determines whether all of the following conditions are met: (a) road sign A indicating that speed breaker B is installed is recognized, (b) the ACC function is operating, (c) vehicle speed V is equal to or less than upper limit threshold Vt, and (d) the vehicle is traveling straight. Since it has been determined in steps S101 and S102 that conditions (a) and (b) are met, vehicle speed adjustment unit 23 further determines whether conditions (c) and (d) are met.

[0063] If the vehicle speed V is equal to or less than the upper limit threshold Vt and the vehicle is traveling straight, the vehicle speed adjustment unit 23 determines that all of the conditions (a) to (d) are satisfied and the first control condition is established, and proceeds to step S104. If the first control condition is not established, this process ends.

[0064] In step S104, the vehicle speed adjustment unit 23 determines whether the above-mentioned second control condition is satisfied. Specifically, it determines whether both of the following conditions are satisfied: (e) the first control condition is satisfied; and (f) there is a deceleration request from the driver. Since it has already been determined in step S103 that condition (e) is satisfied, the vehicle speed adjustment unit 23 determines whether condition (f) is satisfied. When the driver operates, for example, a deceleration request switch of the operation input device 14, the vehicle speed adjustment unit 23 determines that conditions (e) and (f) are satisfied and the second control condition is satisfied, and proceeds to step S106. If the second control condition is not satisfied, the process proceeds to step S105.

[0065] In step S105, vehicle speed adjustment unit 23 executes the first control described above. Specifically, vehicle speed adjustment unit 23 sends a command to braking device 40 to decelerate to first speed V1 at first deceleration a1. In addition, notification unit 24 sends a command to alarm device 30 to display a mark indicating that vehicle speed adjustment control will be executed and to emit a buzzer sound to notify that vehicle speed adjustment control will start. This starts vehicle speed adjustment control, and the control mode transitions from constant speed traveling mode or follow-up traveling mode to the first control mode.

[0066] In step S106, vehicle speed adjustment unit 23 executes the second control described above. Specifically, vehicle speed adjustment unit 23 sends a command to braking device 40 to decelerate to second speed V2 at second deceleration a2. This causes the control mode to transition from the first control mode to the second control mode. After vehicle speed V has decreased to second speed V2, the control mode transitions to low speed holding mode, and vehicle speed adjustment unit 23 sends a command to braking device 40 and drive device 50 to maintain second speed V2. In the second control mode and the low speed holding mode, the mark indicating that vehicle speed adjustment control is being executed continues to be displayed.

[0067] In step S107, vehicle speed adjustment unit 23 determines whether the above-mentioned termination condition is met. Specifically, the termination condition is determined to be met when any one of the following conditions is met: (g) a predetermined distance (termination determination distance) has been traveled since road sign A was recognized, (h) the driver has requested the return of the ACC function by operating a switch, or (i) the driver has accelerated to a predetermined speed or higher by operating the accelerator pedal. If the predetermined distance has been traveled since road sign A was recognized, if the driver has operated the reset switch of operation input device 14, or if the driver has operated the accelerator pedal to increase vehicle speed V to a first speed V1 or higher, vehicle speed adjustment unit 23 determines that the termination condition is met and proceeds to step S108. If the termination condition is not met, the process of step S107 is repeated.

[0068] In step S108, the vehicle speed adjustment control ends, and the operation of the ACC function that was being executed before the start of the vehicle speed adjustment control is restored. The vehicle speed adjustment unit 23 sends a command to the braking device 40 and the drive device 50 to gradually accelerate the vehicle up to the set vehicle speed V0 of the ACC function. With the end of the vehicle speed adjustment control, the mark displayed by the notification device 30 indicating that the vehicle speed adjustment control is being executed is turned off. This ends the processing shown in FIG. 3.

[0069] The vehicle control system 1 according to the present embodiment described above can achieve the following advantageous effects.

[0070] (1) A vehicle control system 1 is configured to execute an ACC function in which, when there is no preceding vehicle in the lane in which the vehicle C is traveling, the vehicle C travels at a constant speed according to a set vehicle speed V0, and, when there is a preceding vehicle, the vehicle C follows the preceding vehicle while maintaining a set inter-vehicle distance. The control device 20 of the control system 1 includes a sign recognition unit 22 configured to recognize a road sign A that prompts the vehicle C to decelerate its vehicle speed V to a predetermined speed, a vehicle speed adjustment unit 23 configured to execute vehicle speed adjustment control to adjust the vehicle speed V of the vehicle C when the sign recognition unit 22 recognizes the road sign A while the ACC function is being executed, and a notification unit 24 that notifies the driver that the vehicle speed adjustment control will be executed by the vehicle speed adjustment unit 23. The vehicle speed adjustment control includes a first control in which, when the sign recognition unit 22 recognizes the road sign A, the vehicle speed V is decelerated to a first speed V1, and a second control in which, during execution of the first control, the vehicle speed V is decelerated to a second speed V2 that is lower than the first speed V1 in response to a deceleration request from the driver.

[0071] Since the system is configured to decelerate in two stages by vehicle speed adjustment control when road sign A is recognized, even while the ACC function is running, the control device 20 can control the vehicle to decelerate appropriately in accordance with road sign A that urges the vehicle to decelerate. This improves the convenience of the ACC function and maintains driver comfort.

[0072] (2) Road sign A is a sign indicating that a convex structure has been installed on the road surface to encourage the driver to slow down. Even when the ACC function is running, the control device 20 can control the vehicle to appropriately slow down when a convex structure is present in front of the vehicle. This improves the convenience of the ACC function and maintains driver comfort.

[0073] (3) The vehicle control system 1 further includes an operation input device 14 (deceleration request switch) that is operated by the driver and receives a deceleration request. The ACC function is configured to be deactivated by operating the brake pedal. The vehicle speed adjustment unit 23 is configured to execute the second control while continuing the operation of the ACC function when the deceleration request switch is operated. A normal ACC function is configured to be deactivated by operating the brake pedal, so if the driver operates the brake pedal before the speed breaker, the operation of the ACC function will be stopped. Therefore, the ACC function will not return to an activated state unless the driver manually operates it again, which is annoying for the driver and reduces the convenience of the ACC function. Therefore, the convenience of the ACC function can be improved by decelerating the vehicle to the second speed V2 by operating the deceleration request switch while continuing the operation of the ACC function.

[0074] (4) In the first control, the first deceleration a1 for decelerating the vehicle speed V to the first speed V1 is smaller than the second deceleration a2 for decelerating the vehicle speed V to the second speed V2 in the second control. The first control is automatically initiated when the sign recognition unit 22 recognizes a road sign A, and therefore the first deceleration a1 is set to a small value so as to gently decelerate the vehicle C without placing an excessive burden on the driver. Even if the sign recognition unit 22 erroneously detects a road sign A, the impact on the driver and the driving can be suppressed by setting the first deceleration a1 to a small value. On the other hand, the second control is initiated by operation of the deceleration operation switch, which reflects the driver's intention to decelerate, and therefore the second deceleration a2 is set to a large value so as to allow sufficient deceleration before the speed breaker B. By setting the first deceleration a1 and the second deceleration a2 in this way, the vehicle can be decelerated gently when moving away from the speed breaker B (first control mode) and can be decelerated sufficiently rapidly when approaching the speed breaker B (second control mode), thereby improving the vehicle's ability to cross the speed breaker B. In addition, it is possible to execute deceleration control that reflects the tendency of actual traffic flow, which is to decelerate rapidly just before the speed breaker B.

[0075] (5) The first deceleration a1 is set to increase as the distance between the vehicle C and road sign A decreases when the road sign A is recognized by the sign recognition unit 22. The distance from the vehicle C to the road sign A when the road sign A is recognized may vary depending on the detection performance of the imaging device 11 and the obstacle detection device 12, the presence or absence of an obstacle that obstructs the visibility of the road sign A, and other factors. Therefore, by setting the first deceleration a1 to increase as the distance between the vehicle C and road sign A decreases, it becomes possible to sufficiently decelerate the vehicle speed V before reaching the speed breaker B.

[0076] (6) The vehicle speed adjustment unit 23 does not execute vehicle speed adjustment control when the vehicle speed V exceeds a preset upper threshold Vt. When the vehicle speed V is in a high vehicle speed range exceeding the upper threshold Vt, the deceleration rate when decelerating to the first speed V1 in the first control becomes large, resulting in a loss of comfort. Furthermore, in high vehicle speed ranges, the detection performance of the imaging device 11 and the obstacle detection device 12 for detecting road signs A decreases, resulting in a loss of accuracy in recognizing road signs A by the sign recognition unit 22. Therefore, by setting an upper threshold Vt for the vehicle speed V for executing vehicle speed adjustment control, it is possible to prevent the execution of vehicle speed adjustment control due to erroneous detection of road signs A, etc., and a loss of comfort.

[0077] (7) When the ACC function is being executed and road sign A is recognized by sign recognition unit 22, vehicle speed adjustment unit 23 is configured to execute vehicle speed adjustment control to decelerate vehicle speed V of vehicle C to second speed V2 (minimum speed). Here, when the accelerator pedal is operated by the driver during vehicle speed adjustment control, vehicle speed adjustment unit 23 is configured to allow an increase in vehicle speed V in response to the operation of the accelerator pedal, to terminate vehicle speed adjustment control when vehicle speed V in response to accelerator pedal operation during vehicle speed adjustment control exceeds first speed V1 which is greater than second speed V2, and to continue operation of vehicle speed adjustment control if the accelerator pedal is operated during vehicle speed adjustment control and vehicle speed V when the accelerator pedal is subsequently released is equal to or less than first speed V1.

[0078] When vehicle speed adjustment control is executed to decelerate vehicle speed V after recognizing road sign A ahead of the vehicle, which indicates a need to decelerate, it is conceivable that the driver may operate the accelerator pedal to accelerate the vehicle because, for example, the vehicle speed V has become slower than the driver intended. As described above, the ACC function temporarily stops operating when the accelerator pedal is operated, but normal operation of the ACC function is restored when the driver releases the accelerator pedal. That is, when the driver releases the accelerator pedal, the vehicle accelerates to the set vehicle speed V0 of the ACC function. If the driver operates the accelerator pedal to accelerate while vehicle speed adjustment control is being executed and then releases the accelerator pedal, there is a possibility that the vehicle will undesirably accelerate to the set vehicle speed V0. Therefore, by configuring the vehicle speed adjustment control to continue operating if vehicle speed V when the accelerator pedal is released is equal to or less than first speed V1, normal operation of the ACC function is restored, preventing unnecessary acceleration of vehicle speed V, and maintaining the effectiveness of the vehicle speed adjustment control. Furthermore, when the vehicle speed V corresponding to the operation of the accelerator pedal during vehicle speed adjustment control exceeds a first speed V1 that is greater than a second speed V2, the vehicle speed adjustment control is terminated and the ACC function returns to normal operation, so that control that reflects the driver's intention to accelerate can be executed.

[0079] (8) When the vehicle speed adjustment control continues to operate after the accelerator pedal is operated, the vehicle speed adjustment unit 23 decelerates the vehicle speed V to the second speed V2 (minimum speed). This allows the vehicle speed V to be sufficiently decelerated.

[0080] (9) When the vehicle speed adjustment control continues to operate after the accelerator pedal is operated, the vehicle speed adjustment unit 23 may maintain the vehicle speed V at the speed when the accelerator pedal is released. This allows the vehicle speed adjustment control to be executed in accordance with the driver's intention.

[0081] -Variations- (1) In the above-described embodiment, if the driver operates the accelerator pedal while the second control is being executed and the vehicle speed when the driver subsequently releases the accelerator pedal is equal to or less than the first speed V1, the vehicle speed adjustment control is continued to be operated. Then, when the vehicle speed adjustment control is continued to be operated, the vehicle speed V is decelerated to the second speed V2 (minimum speed). In the above-described embodiment, the deceleration at this time is set to the second deceleration a2, but this is not limited to this. For example, the deceleration when the vehicle speed adjustment control is continued to be operated to decelerate to the second speed V2 may be smaller than the first deceleration a1 used to decelerate the vehicle speed V to the first speed V1 in the first control. Because the driver operated the accelerator pedal with the intention of accelerating, by gradually decelerating the vehicle when the accelerator pedal is released, the driver is prevented from depressing the accelerator pedal in an attempt to accelerate again, and control that suits the driver's sense can be achieved.

[0082] (2) In the above-described embodiment, a deceleration request by a driver's switch operation is used as the condition (f) for determining whether the second control condition is satisfied. However, this is not limited to this, and the driver's deceleration request is not limited to a switch operation as long as it can be determined that the driver intends to decelerate. For example, the driver's brake pedal operation may also be used as the driver's deceleration request. As described above, the ACC function is configured to stop operation when the brake pedal is operated, so if the driver's brake pedal operation is used as the driver's deceleration request, this is configured as an exception to the normal operation of the ACC function.

[0083] (3) In the above-described embodiment, when the vehicle speed adjustment unit 23 determines that the termination condition is satisfied, the normal operation mode of the ACC function is restored. Here, the acceleration when accelerating to the set vehicle speed V0 of the ACC function may be a fixed set acceleration set in the ACC function, or an acceleration different from the set acceleration may be used. For example, as shown in the constant speed traveling mode after time t4 in FIG. 3, the vehicle may be configured to accelerate at a low acceleration at first and then accelerate at a high acceleration. This prevents the driver from feeling uncomfortable due to sudden acceleration from a vehicle speed lower than the first speed V1, which is the lower limit speed of the ACC function's vehicle speed range.

[0084] (4) In the above-described embodiment, the sign recognition unit 22 recognizes the road sign A based on image data input from the imaging device 11. However, this is not limited to this, and the sign recognition unit 22 may be configured to recognize the presence of the road sign A or a convex structure based on, for example, information obtained through road-to-vehicle communication, map information, or the like.

[0085] (5) In the above-described embodiment, the notification device 30 is configured to emit a buzzer sound when the first control and the second control start to be executed. However, this is not limited to this, and the notification device 30 may be configured to emit a buzzer sound continuously while the first control and / or the second control is being executed.

[0086] (6) In the above-described embodiment, an example was described in which a speed breaker was installed as a convex structure on the road surface to encourage deceleration. However, this is not limited to this, and the above-described embodiment can also be applied to cases in which a different type of convex structure other than a speed breaker is installed. Furthermore, the first speed V1, second speed V2 (minimum speed), etc. are not limited to the values ​​described above. The first speed V1, second speed V2 (minimum speed), etc. may be set to values ​​appropriate for the type of convex structure.

[0087] 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]

[0088] 1 Vehicle control system 20 Control device 21 ACC control unit 22 Sign recognition section 23 Vehicle speed adjustment section 24 Notification Department A road sign B Speed ​​breaker (convex structure) C vehicle

Claims

1. A vehicle control system configured to perform an ACC function in which, when there is no preceding vehicle in the lane in which the vehicle is traveling, the vehicle travels at a constant speed according to a set vehicle speed, and, when there is a preceding vehicle, the vehicle follows the preceding vehicle while maintaining a set inter-vehicle distance, a sign recognition unit configured to recognize a road sign that prompts the driver to slow down the vehicle to a predetermined speed; a vehicle speed adjustment unit configured to execute a vehicle speed adjustment control to reduce the vehicle speed to a minimum speed when the road sign is recognized by the sign recognition unit while the ACC function is being executed; Equipped with The vehicle speed adjustment unit When an accelerator pedal is operated by the driver during the vehicle speed adjustment control, an increase in the vehicle speed in response to the operation of the accelerator pedal is permitted; When the vehicle speed according to the operation of the accelerator pedal during the vehicle speed adjustment control exceeds a first speed that is higher than the minimum speed, the vehicle speed adjustment control is terminated; A vehicle control system configured to continue operation of the vehicle speed adjustment control if the accelerator pedal is operated during the vehicle speed adjustment control and the vehicle speed when the accelerator pedal is subsequently released is equal to or lower than the first speed.

2. The vehicle control system according to claim 1 , wherein the vehicle speed adjustment unit reduces the vehicle speed to the minimum speed when the vehicle speed adjustment control continues to operate after the accelerator pedal is operated.

3. 2. The vehicle control system according to claim 1, wherein the vehicle speed adjustment unit maintains the vehicle speed at the speed when the accelerator pedal is released when the vehicle speed adjustment control continues to operate after the accelerator pedal is operated.

4. the vehicle speed adjustment control includes a first control of decelerating the vehicle speed to the first speed when the road sign is recognized by the sign recognition unit, 3. The vehicle control system of claim 2, wherein the deceleration rate when the vehicle speed is reduced to the minimum speed while the vehicle speed adjustment control continues to operate after the accelerator pedal is operated is smaller than the first deceleration rate for reducing the vehicle speed to the first speed in the first control.

5. a notification unit that notifies a driver that the vehicle speed adjustment control is being executed by the vehicle speed adjustment unit, The road sign indicates that a convex structure for encouraging drivers to slow down is provided on the road surface, The vehicle speed adjustment control includes: a first control for decelerating the vehicle speed to the first speed when the road sign is recognized by the sign recognition unit; a second control for decelerating the vehicle speed to the minimum speed in response to a deceleration request based on a switch operation by the driver while the first control is being executed; 5. A vehicle control system according to claim 1, comprising:

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