Driving assistance device, driving assistance method, driving assistance program, and vehicle

Abstract

To suppress acceleration of a vehicle according to whether or not a pedestrian or the like is likely to suddenly jump out to a road while preventing a driver from feeling troublesome, when the driver feels troublesome due to automatic deceleration and acceleration operations of the vehicle, every time the vehicle approaches a crosswalk.SOLUTION: According to a driving support device comprising a control unit for controlling a driving device that generates driving force of one's own vehicle; the control unit acquires information in front of the one's own vehicle (S10) and controls a driving device in such a manner that a level of target acceleration and an increase amount of the target acceleration are suppressed at a preset suppression degree by driving force suppression control, based on the acquired information, when it is determined that a crosswalk is preset in front of the one's own vehicle, and an opposite lane is congested (S70, S80).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a driving assistance device for a vehicle such as an automobile, a driving assistance method, a driving assistance program, and a vehicle. [Background technology]

[0002] As one type of driving assistance device, a vehicle control device that automatically decelerates a vehicle when a sign that warns of the presence of a pedestrian crossing is recognized is known, as described in the following Patent Document 1. This type of driving assistance device can automatically decelerate the vehicle when the vehicle approaches a pedestrian crossing without requiring the driver to apply the brakes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-089516 A Summary of the Invention

[0004] [Problem to be solved by the invention] In a conventional driving assistance device such as the vehicle control device described in the above Patent Document 1, the vehicle is automatically decelerated every time the vehicle approaches a pedestrian crossing, and the driver must then perform an acceleration operation to increase the vehicle speed. Therefore, the automatic deceleration and acceleration operation can be annoying to the driver.

[0005] When a vehicle approaches a crosswalk and the driver recognizes that there are pedestrians or the like beside the crosswalk, the driver brakes the vehicle to a stop and starts the vehicle after the pedestrians or the like have crossed the road. However, even if the driver recognizes that there are no pedestrians or the like beside the crosswalk, there is a risk that the pedestrians or the like may suddenly jump out onto the road, so it is preferable that the vehicle's acceleration be suppressed when the vehicle passes through a crosswalk, even if the vehicle is not automatically decelerated.

[0006] The main objective of the present invention is to suppress the acceleration of the vehicle depending on whether or not there is a risk of pedestrians or the like suddenly running out onto the road when the vehicle passes through a crosswalk, while avoiding the inconvenience to the driver caused by automatic deceleration and acceleration operations.

[0007] [Means for solving the problems and effects of the invention] According to the present invention, a driving assistance device (100) includes a control unit (driving assistance ECU 10 and driving ECU 20) that controls a driving device (24) that generates a driving force for a host vehicle (50). The control unit acquires information ahead of the host vehicle (S10), and when it determines based on the acquired information that there is a pedestrian crossing ahead of the host vehicle and that the oncoming lane is congested (S20, S40), controls the driving device so that the driving force of the host vehicle is suppressed at a first suppression degree by driving force suppression control. death (S70, S140, S150, S190, S200, S230), When it is determined based on the acquired information that there is a pedestrian crossing ahead of the vehicle and the oncoming lane is not congested (S20, S40), and when it is determined that there is no pedestrian crossing ahead of the vehicle and the oncoming lane is congested (S20, S30), the drive device is controlled so that the driving force of the vehicle is suppressed at a second suppression degree lower than the first suppression degree (S70, S170, S180, S190, S200, S230). A driving assistance device configured to:

[0008] Further, according to the present invention, A driving assistance device including a forward information acquisition device and a control unit, A driving assistance method for controlling a drive device that generates a drive force for a host vehicle, comprising: By using the forward information acquisition device A step (S10) of acquiring information about a front area of ​​the vehicle; Be Based on the information, if there is a pedestrian crossing ahead of the vehicle and the oncoming lane is congested, By the control unit judgement Be At some point (S20, S40), the driving force of the host vehicle is suppressed to a first suppression degree by the driving force suppression control. , by the control unit Steps of controlling the drive device (S70, S140, S150, S190, S200, S230); When the control unit determines based on the acquired information that there is a pedestrian crossing ahead of the host vehicle and the oncoming lane is not congested (S20, S40), and when the control unit determines that there is no pedestrian crossing ahead of the host vehicle and the oncoming lane is congested (S20, S30), the control unit controls the drive device so that the drive force of the host vehicle is suppressed at a second suppression degree that is lower than the first suppression degree (S70, S170, S180, S190, S200, S230); A driving assistance method is provided, including the steps of:

[0009] Further, according to the present invention, there is provided a driving assistance program for causing an electronic control device (a driving assistance ECU 10 and a driving ECU 20) mounted on a vehicle to execute driving assistance for controlling a driving device that generates a driving force for the vehicle, the driving assistance program including a step (S10) of acquiring information about a front area of ​​the vehicle; BeBased on this information, it is determined that there is a pedestrian crossing ahead of the vehicle and that the oncoming lane is congested. Be When the vehicle reaches the threshold (S20, S40), the driving device is controlled so that the driving force of the vehicle is suppressed at a first suppression degree by driving force suppression control (S70, S140, S150, S190, S200, S230); When it is determined based on the acquired information that there is a pedestrian crossing ahead of the host vehicle and the oncoming lane is not congested (S20, S40), and when it is determined that there is no pedestrian crossing ahead of the host vehicle and the oncoming lane is congested (S20, S30), a step of controlling a drive device so that the driving force of the host vehicle is suppressed at a second suppression degree lower than the first suppression degree (S70, S170, S180, S190, S200, S230); A driving assistance program including the following will be provided.

[0010] According to the above driving assistance device, driving assistance method, and driving assistance program, information about the area ahead of the vehicle is acquired, and when it is determined based on the acquired information that there is a crosswalk ahead of the vehicle and that the oncoming lane is congested, the drive device is controlled so that the drive force of the vehicle is suppressed to a first suppression degree by driving force suppression control.

[0011] Therefore, even if there is a pedestrian crossing ahead of the vehicle, the vehicle is not automatically decelerated, and the vehicle is automatically decelerated every time it approaches a pedestrian crossing, and the driver can be prevented from feeling annoyed due to the driver subsequently performing an acceleration operation.

[0012] In addition, when there is a crosswalk ahead of the vehicle and the oncoming lane is congested, there is a high possibility that a pedestrian or the like may suddenly jump out onto the road between the vehicles in the oncoming lane, compared to when the oncoming lane is not congested. In such cases, the driver is often unable to recognize the pedestrian or the like until he or she jumps out from between the vehicles.

[0013] According to the above-mentioned driving assistance device, the driving force of the vehicle is suppressed at a first suppression degree, so that even if a pedestrian or the like suddenly runs out onto the road, the risk of the vehicle colliding with the pedestrian or the like due to the sudden deceleration of the vehicle can be reduced, compared to a case where the driving force of the vehicle is not suppressed at the first suppression degree.

[0015] When there is a crosswalk in front of the vehicle and the oncoming lane is not congested, or when there is no crosswalk in front of the vehicle and the oncoming lane is congested, there is a low risk of pedestrians suddenly running out onto the road compared to when there is a crosswalk in front of the vehicle and the oncoming lane is congested. Conversely, when there is a crosswalk in front of the vehicle and the oncoming lane is not congested, or when there is no crosswalk in front of the vehicle and the oncoming lane is congested, there is a high risk of pedestrians suddenly running out onto the road compared to when there is no crosswalk in front of the vehicle and the oncoming lane is not congested.

[0016] the above Driving support devices, etc. According to the method, when it is determined that there is a crosswalk ahead of the vehicle and the oncoming lane is not congested, and when it is determined that there is no crosswalk ahead of the vehicle and the oncoming lane is congested, the drive device is controlled so that the driving force of the vehicle is suppressed at a second suppression degree lower than the first suppression degree.

[0017] Therefore, while avoiding excessive suppression of the driving force of the vehicle, compared to a case where the driving force of the vehicle is not suppressed to the second suppression degree, the risk of the vehicle colliding with a pedestrian or the like if the pedestrian or the like suddenly runs out onto the road can be reduced due to the vehicle's sudden deceleration.

[0018] [Mode of the invention] The present invention One In one aspect, the control unit (driving assistance ECU 10 and drive ECU 20) is configured to, when it determines based on the acquired information that there is a crosswalk ahead of the host vehicle, the oncoming lane is congested, and there is no other vehicle ahead within a predetermined distance range ahead of the host vehicle (S20, S40, S50), control the drive device so that the driving force of the host vehicle is suppressed at a first suppression degree (S70, S140, S150, S190, S200, S230), and when it determines that there is a crosswalk ahead of the host vehicle, the oncoming lane is congested, and there is another vehicle ahead within a predetermined distance range ahead of the host vehicle (S20, S40, S50), control the drive device so that the inter-vehicle distance between the host vehicle and the other vehicle is equal to or greater than a reference inter-vehicle distance (S60, S210-S230).

[0019] According to the above aspect, when it is determined that there is a pedestrian crossing within a predetermined distance range ahead of the vehicle, the oncoming lane is congested, and there is no other vehicle ahead of the vehicle, the drive device is controlled so that the driving force of the vehicle is suppressed at a first suppression degree. Therefore, since the driving force of the vehicle is suppressed at the first suppression degree, even if a pedestrian or the like suddenly jumps out onto the road, the risk of the vehicle colliding with the pedestrian or the like due to the sudden deceleration of the vehicle can be reduced compared to a case where the driving force of the vehicle is not suppressed at the first suppression degree.

[0020] In addition, in a situation where there is a crosswalk ahead of the vehicle, the oncoming lane is congested, and there is another vehicle ahead of the vehicle within a specified distance range, if a pedestrian or other person suddenly runs out onto the road and the other vehicle suddenly decelerates, there is a risk that the vehicle will rear-end the other vehicle.

[0021] According to the above aspect, when it is determined that there is a crosswalk ahead of the vehicle, the oncoming lane is congested, and another vehicle ahead is within a predetermined distance range ahead of the vehicle, the drive unit is controlled so that the inter-vehicle distance between the vehicle and the other vehicle is equal to or greater than the reference inter-vehicle distance. Therefore, compared to a case where the drive unit is not controlled so that the inter-vehicle distance between the vehicle and the other vehicle is equal to or greater than the reference inter-vehicle distance, it is possible to reduce the risk of the vehicle colliding with the other vehicle when a pedestrian or the like suddenly jumps out onto the road and the other vehicle suddenly decelerates.

[0022] In another aspect of the present invention, the control unit (the driving assistance ECU 10 and the driving ECU 20) Vehicle The higher the vehicle speed, the larger the reference vehicle distance becomes. Vehicle The reference inter-vehicle distance is variably set (S210) according to the vehicle speed.

[0023] In a situation where there is another vehicle ahead of the host vehicle within a predetermined distance range, if the other vehicle suddenly decelerates, the risk of the host vehicle colliding with the other vehicle increases as the vehicle speed of the host vehicle increases. Therefore, the vehicle distance is Vehicle It is preferable that the value is larger as the vehicle speed increases.

[0024] According to the above aspect, Vehicle The higher the vehicle speed, the larger the reference vehicle distance becomes. Vehicle The reference inter-vehicle distance is variably set according to the vehicle speed. Vehicle The higher the vehicle speed, the larger the reference vehicle distance becomes. Vehicle Compared to a case where the reference inter-vehicle distance is not variably set according to vehicle speed, the risk of the host vehicle colliding with another vehicle when the vehicle ahead of the host vehicle within a specified distance range suddenly decelerates can be reduced.

[0025] In another aspect of the present invention, the control unit (the driving assistance ECU 10 and the driving ECU 20) Vehicle The higher the vehicle speed, the higher the degree of first suppression. Vehicle The first suppression degree is variably set in response to the vehicle speed (S170, S180).

[0026] When a pedestrian suddenly jumps out onto the road, it is important to avoid a collision between the vehicle and the pedestrian. Vehicle The higher the vehicle speed, the more difficult it becomes. Vehicle It is preferable that the higher the vehicle speed is, the greater the degree to which the driving force of the host vehicle is suppressed.

[0027] According to the above aspect, Vehicle The higher the vehicle speed, the higher the degree of first suppression. Vehicle The first suppression degree is variably set in accordance with the vehicle speed. Vehicle The higher the vehicle speed, the higher the degree of first suppression. Vehicle Compared to a case where the first suppression degree is not variably set according to the vehicle speed, the risk of the host vehicle colliding with a pedestrian or the like who suddenly runs out onto the road can be reduced even when the host vehicle is traveling at a high speed.

[0028] Furthermore, in another aspect of the present invention, the control units (driving assistance ECU 10 and drive ECU 20) are configured to control the drive device so that the driving force of the vehicle is suppressed by reducing at least one of the ratio of the driving force of the vehicle to the amount of driving operation by the driver and the ratio of the increase in the driving force of the vehicle to the increase in the amount of driving operation by the driver.

[0029] According to the above aspect, the driving force of the host vehicle is suppressed by reducing at least one of the ratio of the driving force of the host vehicle to the driving operation amount of the driver and the ratio of the increase in the driving force of the host vehicle to the increase in the driving operation amount of the driver. Therefore, the driving force of the host vehicle can be reliably suppressed.

[0030] Furthermore, according to the present invention, there is provided a vehicle equipped with the above-mentioned deceleration assistance device. With this vehicle, it is possible to obtain the same effects as those of the above-mentioned deceleration assistance device, deceleration assistance method, and deceleration assistance program.

[0031] In the above description, in order to facilitate understanding of the present invention, the names and / or symbols used in the embodiments described below are added in parentheses to the configurations of the invention corresponding to those embodiments. However, each component of the present invention is not limited to the components of the embodiments corresponding to the names and / or symbols added in parentheses. Other objects, other features, and associated advantages of the present invention will be easily understood from the description of the embodiments of the present invention described below with reference to the drawings. [Brief description of the drawings]

[0032] [Figure 1] 1 is a schematic configuration diagram showing an embodiment of a driving assistance device according to the present invention; [Diagram 2] 5 is a flowchart showing a command control routine for suppressing driving force in the embodiment. [Diagram 3] 4 is a flowchart showing a driving force control routine in the embodiment. [Figure 4] 2 is a map for calculating a correction coefficient Ka of the target acceleration Gdt based on the vehicle speed V. [Diagram 5] 2 is a map for calculating a limited increase amount ΔGdtc of the target acceleration Gdt based on the vehicle speed V. [Figure 6] 11 is a map for calculating a reference inter-vehicle distance Dfc based on a vehicle speed V. [Figure 7] FIG. 13 is a diagram showing a case where there is no pedestrian crossing ahead of a vehicle and the oncoming lane is congested. [Figure 8] FIG. 13 is a diagram showing a case where there is a pedestrian crossing ahead of a vehicle and the oncoming lane is not congested. [Figure 9] FIG. 1 shows a case where there is a pedestrian crossing ahead of a vehicle, the oncoming lane is congested, and there is no preceding vehicle. [Figure 10] 11 is a flowchart showing a case where there is a pedestrian crossing ahead of the vehicle, the oncoming lane is congested, and there is a vehicle ahead. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A driving assistance device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0034] <Configuration> 1, a driving assistance device 100 according to an embodiment is applied to a vehicle 50, and includes a driving assistance ECU 10, a drive ECU 20, a braking ECU 30, and a meter ECU 40. In the following description, the vehicle 50 will be referred to as the host vehicle as necessary in order to distinguish it from other vehicles such as a preceding vehicle.

[0035] Each ECU is an electronic control unit having a microcomputer as its main component, and is connected to each other via a CAN (Controller Area Network) 52 so that they can transmit and receive information to each other. The microcomputer of each ECU includes a CPU, a ROM, a RAM, a non-volatile memory, an interface, etc. The CPU is adapted to realize various functions by executing instructions (programs, routines) stored in the ROM. Some or all of these ECUs may be integrated into one ECU.

[0036] As will be described in detail later, the ROM of the driving assistance ECU 10 stores a command control program for driving force suppression corresponding to the flowchart shown in Fig. 2, and the CPU executes command control for driving force suppression according to the program. The ROM of the drive ECU 20 stores a driving force control program for driving assistance control corresponding to the flowchart shown in Fig. 3, and the CPU executes driving force control according to the program. Thus, the driving assistance ECU 10 and the drive ECU 20 cooperate with each other to function as control units that execute driving force suppression control for driving assistance control corresponding to the flowcharts shown in Figs. 2 and 3.

[0037] 1, the driving assistance ECU 10 is connected to a camera sensor 12, a radar sensor 14, a navigation device 16, and a vehicle speed sensor 18. As described later, the camera sensor 12 and the radar sensor 14 function as a forward information acquisition device that acquires information about the area ahead of the vehicle 50.

[0038] Although not shown in the figure, the camera sensor 12 includes a camera unit and a recognition unit that analyzes image data captured by the camera unit to recognize targets such as white lines on a road, pedestrian crossings, road signs, traffic lights, and other vehicles. The camera unit of the camera sensor 12 captures images of the scenery ahead of the vehicle 50. The recognition unit of the camera sensor 12 supplies information about the recognized targets to the driving assistance ECU 10 at predetermined time intervals. Note that a LiDAR (Light Detection And Ranging) may be used instead of the camera sensor 12.

[0039] The radar sensor 14 includes a radar transmitting / receiving unit and a signal processing unit (not shown), and the radar transmitting / receiving unit emits millimeter-wave band radio waves (hereinafter referred to as "millimeter waves") and receives millimeter waves (i.e., reflected waves) reflected by three-dimensional objects (e.g., other vehicles, bicycles, guardrails, etc.) present within the emission range. The signal processing unit acquires information (hereinafter referred to as surrounding information) indicating the distance between the vehicle and the three-dimensional object, the relative speed between the vehicle and the three-dimensional object, the relative position (direction) of the three-dimensional object with respect to the vehicle, etc., based on the phase difference between the transmitted millimeter waves and the received reflected waves, the attenuation level of the reflected waves, and the time from transmitting the millimeter waves to receiving the reflected waves, and supplies the information to the driving assistance ECU 10 at predetermined time intervals.

[0040] The navigation device 16 includes a GPS receiver that detects the position of the vehicle 50, a storage device that stores map information and road information, and a communication device that acquires the latest map information and road information from an external device. The road information includes information on pedestrian crossings. When there is a sidewalk ahead of the vehicle, the navigation device 16 outputs a signal indicating this to the driving assistance ECU 10 based on the vehicle's position on the map and the road information.

[0041] The vehicle speed sensor 18 detects the vehicle speed V of the vehicle 50, and supplies a signal indicating the vehicle speed V to the driving assistance ECU 10 at predetermined time intervals. At least one of the camera sensor 12, the radar sensor 14, the navigation device 16, and the vehicle speed sensor 18 may be connected to the CAN 52.

[0042] The drive ECU 20 is connected to an accelerator opening sensor 22 and a drive device 24 that generates a drive force for the vehicle 50. The accelerator opening sensor 22 detects an accelerator opening Acc that indicates the amount of drive operation by the driver, and supplies a signal that indicates the accelerator opening Acc to the driving assistance ECU 10. The drive device 24 includes an engine actuator 26 and an engine 28.

[0043] The engine actuator 26 is an actuator for changing the operating state of the engine 28, and includes, for example, a throttle valve actuator for changing the opening of a throttle valve. The drive ECU 20 calculates a target acceleration Gdt of the vehicle based on the accelerator opening Acc detected by the accelerator opening sensor 22, and controls the operation of the engine actuator 26 so that the driving force of the vehicle 50 corresponds to the target acceleration Gdt.

[0044] When the drive ECU 20 receives a drive force suppression command from the driving assistance ECU 10, it controls the operation of the engine actuator 26 to suppress the output torque (drive force of the vehicle 50) generated by the engine 28. If the vehicle is an electric vehicle, the engine actuator 26 is a drive device for the electric motor, and if the vehicle is a hybrid vehicle, the engine actuator 26 is a drive device for the engine actuator and the electric motor.

[0045] The brake ECU 30 is connected to a pressure sensor 32 and a brake device 34 that generates a braking force for the vehicle 50. The pressure sensor 32 detects a master cylinder pressure Pm that indicates the amount of braking operation by the driver, and supplies a signal indicating the master cylinder pressure Pm to the driving assistance ECU 10. The brake device 34 includes a brake actuator 36 and a friction brake mechanism 38.

[0046] The brake actuator 32 is provided in a hydraulic circuit between a master cylinder (not shown) that pressurizes hydraulic fluid in response to the depression force of the brake pedal, and friction brake mechanisms 38 provided on the left and right front wheels and the left and right rear wheels. The friction brake mechanisms 38 include brake discs 38a that rotate together with the corresponding wheels, and brake calipers 38b supported by the vehicle body (not shown). The brake actuator 32 adjusts the hydraulic pressure supplied to a wheel cylinder built into the brake caliper 38b in response to a command from the braking ECU 30, and generates a friction braking force by pressing brake pads (not shown) against the brake discs 38a with the hydraulic pressure.

[0047] The brake ECU 30 calculates a target deceleration of the vehicle 50 based on the master cylinder pressure Pm detected by the pressure sensor 32, and controls the operation of the brake actuator 32 so that the deceleration of the vehicle becomes the target deceleration. When the brake ECU 30 receives a braking command such as for collision prevention from the driving assistance ECU 10, the brake ECU 30 controls the operation of the brake actuator 32 so that the vehicle 50 decelerates at a required deceleration included in the braking command.

[0048] A display 42 is connected to the meter ECU 40. When a driving force suppression command is output from the driving assistance ECU 10 (when a driving force suppression flag F described later is 1 to 3 and the driving force is suppressed), the meter ECU 40 displays on the display 42 that the driving force is being suppressed. The display 42 is, for example, a head-up display or a multi-information display that displays meters and various information.

[0049] <Command control routine for suppressing driving force> Next, a command control routine for suppressing driving force in the embodiment will be described with reference to the flowchart shown in Fig. 2. The command control for suppressing driving force according to the flowchart shown in Fig. 2 is repeatedly executed by the CPU of the driving support ECU 10 at a predetermined control period when a driving support switch not shown in Fig. 1 is on. In the following description of the command control, the command control for suppressing driving force will be simply referred to as "command control." In the following description of the command control, the CPU is the CPU of the driving support ECU 10.

[0050] First, in step S10, the CPU determines targets such as white lines on the road ahead of the vehicle 50, pedestrian crossings, other vehicles, etc., based on information supplied from the camera sensor 12 and the radar sensor 14, and determines the distances to those targets.

[0051] In step S20, the CPU determines whether or not there is a pedestrian crossing within a range of a predetermined distance (positive constant) ahead of the vehicle 50. If the CPU determines yes, it advances command control to step S40, and if the CPU determines no, it advances command control to step S30. Note that information from the navigation device 16 may also be used when determining whether or not there is a pedestrian crossing.

[0052] In this case, the crosswalk may be either a crosswalk with a traffic light or a crosswalk without a traffic light, but this control is executed when the traffic light at a crosswalk with a traffic light is green as seen from the vehicle 50. If the traffic light at a crosswalk with a traffic light is red or yellow as seen from the vehicle 50, the driver will decelerate and stop the vehicle 50, so this control is not executed and, for example, a warning that the traffic light is red or yellow may be displayed on the display device 42.

[0053] In step S30, the CPU judges whether the oncoming lane is congested. If the CPU judges yes, the CPU advances command control to step S80, and if the CPU judges no, the CPU advances command control to step S90. In this case, the oncoming lane may be judged to be congested when there are a reference number (a positive integer) or more of other vehicles within a distance (a positive constant) for judging congestion in the oncoming lane and the speed of the fastest vehicle among those other vehicles is equal to or less than the reference speed (a positive constant).

[0054] In step S40, the CPU determines whether or not the oncoming lane is congested, similarly to step S30. If the CPU determines that the oncoming lane is congested, the CPU advances command control to step S80, and if the CPU determines that the oncoming lane is congested, the CPU advances command control to step S50.

[0055] In step S50, the CPU determines whether or not there is another vehicle ahead of the host vehicle 50 and within a distance (positive constant) from the host vehicle that is the preceding vehicle determination distance. If the CPU determines that there is a negative determination, it advances command control to step S70, and if the CPU determines that there is a positive determination, it advances command control to step S60.

[0056] In step S60, the CPU transmits a signal indicating that flag F is 3 to the drive ECU 20, thereby outputting a command to the drive ECU 20 to increase the inter-vehicle distance between the host vehicle 50 and the preceding vehicle.

[0057] In step S70, the CPU transmits a signal indicating that the flag F is 1 to the drive ECU 20, thereby outputting a command to the drive ECU 20 to suppress the drive force of the vehicle 50 at the first suppression degree.

[0058] In step S80, the CPU sends a signal indicating that flag F is 2 to the drive ECU 20, thereby outputting a command to the drive ECU 20 to suppress the driving force of the vehicle 50 at a second suppression degree lower than the first suppression degree.

[0059] In step S90, the CPU transmits a signal indicating that the flag F is 0 to the drive ECU 20, thereby outputting a command to the drive ECU 20 to perform normal control without suppressing the drive force of the vehicle 50.

[0060] The flag F is initialized to 0 when the command control starts, and is then set to 0 to 3 as described above according to the flowchart shown in FIG. 2. For example, the flag F may be composed of flags Fa and Fb. In this case, when flags Fa and Fb are 0, the flag F is 0, and when flags Fa are 1 and Fb are 0, the flag F is 1. Furthermore, when flags Fa are 0 and Fb are 1, the flag F is 2, and when flags Fa and Fb are 1, the flag F is 3.

[0061] <Driving force control routine> Next, a driving force control routine in the embodiment will be described with reference to the flowchart shown in Fig. 3. The driving force control according to the flowchart shown in Fig. 3 is repeatedly executed by the CPU of the driving ECU 20 at a predetermined control period when a driving support switch, not shown in Fig. 1, is on. In the following description of the driving force control, the CPU is the CPU of the driving ECU 20.

[0062] First, in step S110, the CPU determines whether or not the flag F is 0, that is, whether or not normal control should be performed without suppressing the driving force of the vehicle 50. If the CPU makes a negative determination, it advances the driving force control to step S130, and if the CPU makes a positive determination, it advances the driving force control to step S120.

[0063] In step S120, the CPU sets the correction coefficient Ka of the target acceleration Gdt of the vehicle 50 to 1, and sets the limited increase amount ΔGdtc of the target acceleration Gdt to ΔGdt3. Note that the limited increase amount ΔGdtc is a maximum value that allows an increase in the target acceleration Gdt for each cycle of the driving force control according to the flowchart shown in Fig. 3, and ΔGdt3 is a positive constant that is large enough not to limit the increase in the target acceleration Gdt due to the driving operation of the driver.

[0064] In step S130, the CPU determines whether or not the flag F is 1, that is, whether or not the driving force of the vehicle 50 should be suppressed by the first suppression degree. If the CPU makes a negative determination, it proceeds to step S160 for the driving force control, and if the CPU makes a positive determination, it proceeds to step S140 for the driving force control.

[0065] In step S140, the CPU calculates a modification coefficient Ka (first modification coefficient Ka1) for the target acceleration Gdt of the vehicle 50 by referring to the map shown by the solid line in Fig. 4 based on the vehicle speed V. As shown in Fig. 4, the first modification coefficient Ka1 is variably set according to the vehicle speed so that it becomes smaller within a range of 1 or less and larger than 0 as the vehicle speed V becomes higher.

[0066] In step S150, the CPU calculates a limited increase ΔGdtc (first limited increase ΔGdt1) of the target acceleration Gdt of the vehicle 50 by referring to the map shown by the solid line in Fig. 5 based on the vehicle speed V. As shown in Fig. 5, the first limited increase ΔGdt1 is variably set according to the vehicle speed so that it increases as the vehicle speed V increases.

[0067] In step S160, the CPU determines whether or not flag F is 2, that is, whether or not the driving force of the vehicle 50 should be suppressed by the second suppression degree. If the CPU makes a negative determination, it proceeds to step S210 for the driving force control, and if the CPU makes a positive determination, it proceeds to step S170 for the driving force control.

[0068] In step S170, the CPU calculates a modification coefficient Ka (second modification coefficient Ka2) for the target acceleration Gdt of the vehicle 50 by referring to the map indicated by the dashed line in Fig. 4 based on the vehicle speed V. As shown in Fig. 4, the second modification coefficient Ka2 is larger than the first modification coefficient Ka1, and is variably set according to the vehicle speed so as to become smaller within a range of 1 or less and greater than 0 as the vehicle speed V becomes higher.

[0069] In step S180, the CPU calculates a limited increase ΔGdtc (second limited increase ΔGdt2) of the target acceleration Gdt of the vehicle 50 by referring to the map indicated by the dashed line in Fig. 5 based on the vehicle speed V. As shown in Fig. 5, the second limited increase ΔGdt2 is larger than the first limited increase ΔGdt1 and is variably set according to the vehicle speed so as to become larger as the vehicle speed V becomes higher.

[0070] In step S190, the CPU calculates the target acceleration Gdt of the vehicle 50 based on the accelerator opening Acc and the correction coefficient Ka, using Kg as a conversion coefficient from the accelerator opening Acc to the target acceleration Gdt of the vehicle 50, according to the following equation (1). Gdt = Kg Ka Acc … (1)

[0071] In step S200, the CPU calculates the increase amount ΔGdt (=Gdt-Gdtf) of the target acceleration Gdt, using the previous value of the target acceleration Gdt as Gdtf, and when the increase amount ΔGdt exceeds the restricted increase amount ΔGdtc, the target acceleration Gdt is reduced to Gdtf+ΔGdtc. That is, the CPU limits the increase of the target acceleration Gdt by the restricted increase amount ΔGdtc. Note that when the increase amount ΔGdt does not exceed the restricted increase amount ΔGdtc, the target acceleration Gdt is not reduced.

[0072] In step S210, the CPU calculates a reference inter-vehicle distance Dfc by referring to a map shown in Fig. 6 based on the vehicle speed V. As shown in Fig. 6, the reference inter-vehicle distance Dfc is variably set according to the vehicle speed so that it increases as the vehicle speed V increases.

[0073] In step S220, when the inter-vehicle distance Df between the host vehicle 50 and the preceding other vehicle is less than the reference inter-vehicle distance Dfc, the CPU calculates a target acceleration Gdt of the vehicle 50 for making the inter-vehicle distance Df equal to the reference inter-vehicle distance Dfc in a manner known in the art. Although not shown in FIG. 3, when the inter-vehicle distance Df is greater than or equal to the reference inter-vehicle distance Dfc, the CPU advances the driving force control to step S170.

[0074] In step S230, the CPU controls the engine 28 via the engine actuator 26 so that the acceleration Gd of the vehicle 50 becomes the target acceleration Gdt. The CPU decelerates the vehicle 50 by controlling the braking device 34 via the braking ECU 30 as necessary.

[0075] <Operation of the embodiment> <C1. When there is no crosswalk in front of the vehicle 50 and the oncoming lane is not congested> In steps S20 and S30, since a negative determination is made, in step S90, the flag F is set to 0. Therefore, in step S110, an affirmative determination is made, and in step S120, the correction coefficient Ka of the target acceleration Gdt of the vehicle 50 is set to 1, and the restricted increase amount ΔGdtc of the target acceleration Gdt is set to ΔGdt3.

[0076] Therefore, the target acceleration Gdt of the vehicle 50 is calculated as the product of the conversion coefficient Kg and the accelerator opening Acc in step S190, and in step S200, the increase of the target acceleration Gdt is not restricted. Thus, the acceleration Gd of the vehicle 50 is controlled by normal control that is not subject to suppression by the driving support control in step S230.

[0077] <C2. When there is no crosswalk in front of the vehicle 50 and the oncoming lane is congested> As shown in FIG. 7, C2 is a case where the vehicle 50 is traveling in the lane 60, there is no crosswalk in front of the vehicle 50, the oncoming lane 62 is congested, and a number of vehicles 64 are traveling at a low speed or stopped.

[0078] In step S20, a negative determination is made. In step S30, an affirmative determination is made. In step S80, the flag F is set to 2. Therefore, in steps S110 and S130, negative determinations are made, and in step S160, an affirmative determination is made. Further, in step S170, the correction coefficient Ka of the target acceleration Gdt of the vehicle 50 is calculated as the second correction coefficient Ka2, and in step S180, the limited increase amount ΔGdtc of the target acceleration Gdt is calculated as the second limited increase amount ΔGdt2.

[0079] Therefore, in step S190, the target acceleration Gdt of the vehicle 50 is calculated as the product of the second correction coefficient Ka2, the conversion coefficient Kg, and the accelerator opening Acc. In step S200, the increase in the target acceleration Gdt is limited by the second limited increase amount ΔGdt2. Thus, the magnitude and increase of the acceleration Gd of the vehicle 50 are suppressed by the second suppression degree compared to the normal control, so that it is possible to ensure the possibility of coping with a pedestrian or the like jumping out in front of the own vehicle from between the congested vehicles in the oncoming lane by deceleration or the like.

[0080] <C3. When there is a crosswalk in front of the vehicle 50 and the oncoming lane is not congested> As shown in FIG. 8, C3 is a case where the vehicle 50 is traveling in the lane 60, there is a crosswalk 66 in front of the vehicle 50, the oncoming lane 62 is not congested, and other vehicles 64 are also traveling smoothly.

[0081] In step S20, an affirmative determination is made, and in step S40, a negative determination is made. Therefore, in step S80, flag F is set to 2. Thus, similar to the case of C2 above, the magnitude of the acceleration Gd of the vehicle 50 and the magnitude and increase of the driving force corresponding to the increase are suppressed at a second suppression level compared to normal control. Therefore, even if a pedestrian or the like jumps out onto the sidewalk in front of the host vehicle, it is possible to ensure the possibility of coping with it by deceleration or the like.

[0082] Note that the second correction coefficient Ka2 is variably set according to the vehicle speed V so that it becomes smaller as the vehicle speed V is higher, and the second limit increase amount ΔGdt2 is variably set according to the vehicle speed V so that it becomes larger as the vehicle speed V is higher. Therefore, in the cases of C2 and C3 above, the higher the vehicle speed V and the longer the braking distance, the higher the second suppression level for the driving force can be made. Therefore, compared to the case where the second suppression level is constant regardless of the vehicle speed V, even if a pedestrian or the like jumps out in front of the host vehicle from between the congested vehicles in the oncoming lane, the possibility of coping with it by deceleration can be increased.

[0083] Also, the second suppression level is lower than the first suppression level in the case of C3 described later. Therefore, also in the cases of C2 and C3, compared to the case where the magnitude and increase of the driving force are suppressed at the second suppression level, it is possible to reduce the possibility that the driver feels dissatisfaction due to the acceleration Gd of the vehicle 50 being excessively suppressed.

[0084] <C4. There is a crosswalk in front of the vehicle 50, the oncoming lane is congested, and there is no preceding vehicle> As shown in FIG. 9, C4 is a case where the vehicle 50 is traveling in the lane 60, there is a crosswalk 66 in front of the vehicle 50, the oncoming lane 62 is congested, and there is no other vehicle traveling ahead in the lane 60 within a predetermined distance range in front of the vehicle 50.

[0085] In steps S20 and S40, an affirmative determination is made. In step S50, a negative determination is made. In step S70, flag F is set to 1. Therefore, in step S110, a negative determination is made. In step S130, an affirmative determination is made. In step S140, the correction coefficient Ka of the target acceleration Gdt of the vehicle 50 is calculated as the first correction coefficient Ka1. In step S150, the restricted increase amount ΔGdtc of the target acceleration Gdt is calculated as the first restricted increase amount ΔGdt1.

[0086] Therefore, in step S190, the target acceleration Gdt of the vehicle 50 is calculated as the product of the first correction coefficient Ka1, the conversion coefficient Kg, and the accelerator opening Acc. In step S200, the increase in the target acceleration Gdt is restricted by the first restricted increase amount ΔGdt1. Therefore, the magnitude of the acceleration Gd of the vehicle 50 and the magnitude and increase of the driving force corresponding to the increase are suppressed with a first suppression degree higher than the second suppression degree. Thus, even if a pedestrian or the like jumps out in front of the host vehicle from between the congested vehicles in the oncoming lane, the possibility of being able to cope by deceleration or the like can be increased.

[0087] Note that the first correction coefficient Ka1 is variably set according to the vehicle speed V so as to become smaller as the vehicle speed V is higher. The first restricted increase amount ΔGdt1 is variably set according to the vehicle speed V so as to become larger as the vehicle speed V is higher. Therefore, in the case of C4 above, as the vehicle speed V is higher and the braking distance is longer, the first suppression degree with respect to the driving force can be increased. Thus, compared with the case where the first suppression degree is constant regardless of the vehicle speed V, the possibility of coping with the jumping out of a pedestrian or the like can be increased.

[0088] <C5. When there is a crosswalk in front of the vehicle 50, the oncoming lane is congested, and there is a preceding vehicle> As shown in FIG. 10, C5 is a case where the vehicle 50 is traveling in the lane 60, there is a crosswalk 66 in front of the vehicle 50, the oncoming lane 62 is congested, and there is another vehicle 68 traveling ahead in the lane 60 within a predetermined distance range in front of the vehicle 50.

[0089] In steps S20, S40, and S50, positive determinations are made, and in step S60, flag F is set to 3. Therefore, in steps S110, S130, and S160, negative determinations are made, and in step S210, a reference inter-vehicle distance Dfc is calculated. Furthermore, in step S220, when the inter-vehicle distance Df between the host vehicle 50 and the preceding vehicle is less than the reference inter-vehicle distance Dfc, a target acceleration Gdt of the vehicle 50 for bringing the inter-vehicle distance Df to the reference inter-vehicle distance Dfc is calculated.

[0090] Therefore, when there is a crosswalk ahead of the vehicle 50, the oncoming lane is congested, and there is a preceding vehicle, the target acceleration Gdt is calculated so that the inter-vehicle distance Df between the host vehicle 50 and the preceding vehicle does not become less than the reference inter-vehicle distance Dfc, and the driving force of the host vehicle 50 is controlled based on the target acceleration Gdt. Therefore, compared to the case where the driving force control is not performed to control the inter-vehicle distance as described above, it is possible to reduce the risk of the host vehicle 50 colliding with the preceding vehicle even when a pedestrian or the like jumps out in front of the preceding vehicle and the preceding vehicle suddenly decelerates.

[0091] The reference inter-vehicle distance Dfc is variably set according to the vehicle speed V so that it increases as the vehicle speed V increases. Therefore, in the case of C5 described above, the higher the vehicle speed V and the longer the braking distance, the greater the inter-vehicle distance Df between the host vehicle 50 and the preceding vehicle can be. This increases the possibility of reducing the risk of the host vehicle 50 colliding with the preceding vehicle, compared to when the reference inter-vehicle distance Dfc is constant regardless of the vehicle speed V.

[0092] As described above, the driving assistance method and driving assistance program of the present invention include a step of acquiring information about the area ahead of the vehicle, and when it is determined based on the acquired information that there is a crosswalk ahead of the vehicle and that the oncoming lane is congested, a step of controlling the drive device so that the driving force of the vehicle is suppressed to a first suppression degree by driving force suppression control.

[0093] The former step corresponds to step S10 in Fig. 2 and is executed by the CPU of the driving assistance ECU 10. The judgment in the latter step corresponds to steps S20 and S40 in Fig. 2 and is executed by the CPU of the driving assistance ECU. Furthermore, the control of the drive device in the latter step corresponds to steps S70, S140, S150, S190, S200, and S230 in Fig. 3 and is executed by the CPU of the drive ECU 30.

[0094] As can be seen from the above description, according to the embodiment, even if there is a pedestrian crossing ahead of the vehicle, the vehicle is not automatically decelerated, so that the driver can be prevented from feeling annoyed when the vehicle automatically decelerates every time the vehicle approaches a pedestrian crossing and then accelerates. Furthermore, when there is a pedestrian crossing ahead of the vehicle and / or the oncoming lane is congested, the driving force of the vehicle is suppressed at the first or second suppression degree, so that even if a pedestrian or the like suddenly jumps out onto the road, the risk of the vehicle colliding with the pedestrian or the like due to the sudden deceleration of the vehicle can be reduced compared to when the driving force of the vehicle is not suppressed.

[0095] In particular, according to the embodiment, both the magnitude of the target acceleration Gdt and the increase amount ΔGdt of the target acceleration are limited, so that the driving force of the host vehicle can be effectively suppressed compared to a case in which only one of the magnitude of the target acceleration Gdt and the increase amount ΔGdt of the target acceleration is limited.

[0096] Furthermore, according to the embodiment, when the driving force of the host vehicle is suppressed by the driving force suppression control, the fact that the driving force is being suppressed by the driving force suppression control is displayed on the display 42. This reduces the risk that the driver will feel a lack of driving force and perform an unnecessary acceleration operation.

[0097] Although the present invention has been described in detail above with reference to specific embodiments, it will be apparent to those skilled in the art that the present invention is not limited to the above-described embodiments, and that various other embodiments are possible within the scope of the present invention.

[0098] For example, in the above embodiment, both the magnitude of the target acceleration Gdt and the increase amount ΔGdt of the target acceleration are limited. However, the present invention may be modified so that only one of the magnitude of the target acceleration Gdt and the increase amount ΔGdt of the target acceleration is limited.

[0099] In the above embodiment, the first modification coefficient Ka1 and the second modification coefficient Ka2 are variably set according to the vehicle speed V so as to become smaller as the vehicle speed V increases. However, at least one of the first modification coefficient Ka1 and the second modification coefficient Ka2 may be constant regardless of the vehicle speed V.

[0100] In the above embodiment, the first limited increase amount ΔGdt1 and the second limited increase amount ΔGdt2 are variably set according to the vehicle speed V so as to become larger as the vehicle speed V increases. However, at least one of the first limited increase amount ΔGdt1 and the second limited increase amount ΔGdt2 may be constant regardless of the vehicle speed V.

[0101] In the above embodiment, in step S210, the reference inter-vehicle distance Dfc is variably set according to the vehicle speed so as to become larger as the vehicle speed V increases. However, the reference inter-vehicle distance Dfc may be constant regardless of the vehicle speed V. Also, the reference inter-vehicle distance Dfc may be variably set according to the relative speed Vr of the host vehicle relative to the preceding vehicle so as to become larger as the relative speed Vr of the host vehicle increases.

[0102] In the above embodiment, the driving force control according to the flowchart shown in Fig. 3 is executed by the CPU of the drive ECU 20. However, at least a part of the steps of the flowchart shown in Fig. 3 may be executed by the CPU of the driving assistance ECU 10.

[0103] Furthermore, in the above-described embodiment, in the case of C5, i.e., when there is a crosswalk ahead of the vehicle 50, the oncoming lane is congested, and there is a preceding vehicle, a reference inter-vehicle distance Dfc is calculated, and when the inter-vehicle distance Df between the vehicle 50 and the preceding vehicle is less than the reference inter-vehicle distance Dfc, a target acceleration Gdt of the vehicle 50 is calculated to set the inter-vehicle distance Df to the reference inter-vehicle distance Dfc. However, when there is a pedestrian crossing ahead of the vehicle 50 and the oncoming lane is congested, regardless of whether there is a preceding vehicle or not, the magnitude and increase of the driving force corresponding to the magnitude and increase of the acceleration Gd of the vehicle 50 may be modified to be suppressed to a first suppression degree compared to that during normal control, similar to the case of C4 described above. [Explanation of symbols]

[0104] 10...driving assistance ECU, 12...camera sensor, 14...radar sensor, 16...navigation device, 18...vehicle speed sensor, 20...drive ECU, 22...accelerator opening sensor, 24...drive device, 28...engine, 30...braking ECU, 38...braking mechanism, 40...meter ECU, 50...vehicle, 62...oncoming lane, 66...pedestrian crossing, 100...driving assistance device

Claims

1. A driving assistance device including a control unit for controlling a drive device that generates a drive force for a host vehicle, The control unit is configured to acquire information about the area ahead of the host vehicle, and when it is determined based on the acquired information that there is a crosswalk ahead of the host vehicle and the oncoming lane is congested, control the drive device so that the drive force of the host vehicle is suppressed at a first suppression degree through drive force suppression control, and when it is determined based on the acquired information that there is a crosswalk ahead of the host vehicle and the oncoming lane is not congested, and when it is determined that there is no crosswalk ahead of the host vehicle and the oncoming lane is congested, control the drive device so that the drive force of the host vehicle is suppressed at a second suppression degree lower than the first suppression degree.

2. 2. The driving assistance device according to claim 1, wherein the control unit is configured to, when it determines based on the acquired information that there is a crosswalk ahead of the host vehicle, the oncoming lane is congested, and there is no other vehicle ahead within a predetermined distance range ahead of the host vehicle, control the drive device so that the driving force of the host vehicle is suppressed at a first suppression degree, and when it determines that there is a crosswalk ahead of the host vehicle, the oncoming lane is congested, and there is another vehicle ahead within the predetermined distance range ahead of the host vehicle, control the drive device so that the inter-vehicle distance between the host vehicle and the other vehicle is equal to or greater than a reference inter-vehicle distance.

3. 3. The driving assistance device according to claim 2, wherein the control unit is configured to variably set the reference inter-vehicle distance in accordance with the vehicle speed of the host vehicle such that the reference inter-vehicle distance becomes larger as the vehicle speed of the host vehicle increases.

4. 4. The driving assistance device according to claim 1, wherein the control unit is configured to variably set the first suppression degree in accordance with a vehicle speed of the host vehicle such that the first suppression degree becomes higher as the vehicle speed of the host vehicle becomes higher.

5. 5. A driving assistance device according to any one of claims 1 to 4, wherein the control unit is configured to control the drive device so that the driving force of the vehicle is suppressed by reducing at least one of a ratio of the driving force of the vehicle to an amount of driving operation by a driver and a ratio of an increase in the driving force of the vehicle to an increase in the amount of driving operation by the driver.

6. A driving assistance method for controlling a drive device that generates a driving force for a vehicle by a driving assistance device including a forward information acquisition device and a control unit, A driving assistance method including the steps of: acquiring information ahead of the host vehicle by the forward information acquisition device; when the control unit determines based on the acquired information that there is a crosswalk ahead of the host vehicle and that the oncoming lane is congested, controlling the drive device by the control unit so that the drive force of the host vehicle is suppressed at a first suppression degree by drive force suppression control; and when the control unit determines based on the acquired information that there is a crosswalk ahead of the host vehicle and that the oncoming lane is not congested, and when the control unit determines that there is no crosswalk ahead of the host vehicle and that the oncoming lane is congested, controlling the drive device by the control unit so that the drive force of the host vehicle is suppressed at a second suppression degree lower than the first suppression degree.

7. A driving assistance program for causing an electronic control device mounted on a vehicle to execute driving assistance for controlling a drive device that generates a driving force for the vehicle, comprising: A driving assistance program comprising: a step of acquiring information about a region ahead of the host vehicle; and when it is determined based on the acquired information that there is a crosswalk ahead of the host vehicle and that the oncoming lane is congested, a step of controlling the drive device so that the drive force of the host vehicle is suppressed at a first suppression degree by drive force suppression control; and when it is determined based on the acquired information that there is a crosswalk ahead of the host vehicle and that the oncoming lane is not congested, and when it is determined that there is no crosswalk ahead of the host vehicle and that the oncoming lane is congested, a step of controlling the drive device so that the drive force of the host vehicle is suppressed at a second suppression degree lower than the first suppression degree.

8. A vehicle comprising a driving assistance device according to any one of claims 1 to 5.

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