Driving Support Devices

Abstract

To provide a driving support device which can avoid generation of an event in which, when a driving support device which executes following travel control for following another vehicle travelling in front of an own vehicle and travelling and specific speed reduction control for avoiding getting closer to a pedestrian (object pedestrian) executes both of these controls together, when an object pedestrian is newly detected after the execution of the specific speed reduction control is finished, the travel speed of the own vehicle has become relatively large or a distance with the newly detected object pedestrian has become small.SOLUTION: When the magnitude of the speed reduction degree required for specific speed reduction control becomes larger than the magnitude of the speed reduction degree required for following travel control, the execution of the following travel control is stopped.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a driving assistance device that performs follow-up cruise control for controlling the driving force and braking force of a host vehicle so that the inter-vehicle distance between the host vehicle and another vehicle traveling ahead of the host vehicle coincides with a target inter-vehicle distance. [Background technology]

[0002] There is known a driving support device that performs collision avoidance control (deceleration control) that generates a braking force for the host vehicle to avoid the host vehicle colliding with a three-dimensional target in addition to the following cruise control. One of these driving support devices (hereinafter also referred to as a "conventional device") stops the following cruise control when the required acceleration for the following cruise control is a negative value and the magnitude of the required acceleration is smaller than the magnitude of the deceleration required to avoid a collision with a "collision determination object" that is an object with a high probability of colliding with the host vehicle (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-001188 A Summary of the Invention

[0004] Generally, compared to a vehicle, a pedestrian's traveling direction and speed can change in a short time. Therefore, even when there is a pedestrian who is not currently within the predicted traveling area (passage area) of the vehicle and therefore has a relatively low possibility of collision, it is desirable to appropriately reduce the traveling speed of the vehicle. However, in the conventional device, it has not been considered to reduce the traveling speed of the vehicle in advance, particularly to avoid a collision with a pedestrian.

[0005] Therefore, one object of the present invention is to provide a driving assistance device that can execute deceleration control for a pedestrian who is not currently present in the vehicle's passing area, and can stop the execution of following driving control at an appropriate timing when the deceleration control is being executed.

[0006] A driving assistance device for achieving the above object (hereinafter also referred to as "the device of the present invention") includes a target detection device, a braking / driving force control device, and a controller.

[0007] The target detection device (the front camera 31 and the driving assistance ECU 21) A three-dimensional target present in the area ahead of the vehicle (10) is detected.

[0008] The braking / driving force control device (the driving control ECU 22 and the braking control ECU 23) The driving force and braking force of the vehicle are controlled.

[0009] The controller (driving assistance ECU 21) A following acceleration (Af) is obtained, which is the acceleration required to make the inter-vehicle distance between the vehicle and the "vehicle to be followed" that is the detected three-dimensional target traveling in front of the vehicle, match the target inter-vehicle distance, and a "following driving control" is executed to control the braking / driving force control device so that the actual acceleration of the vehicle matches the following acceleration (steps 515, 555, and 560 in FIG. 5).

[0010] In addition, the controller When there is a "target pedestrian" that is the detected three-dimensional object approaching the vehicle passage area through which the vehicle is expected to pass, a "specific deceleration" which is a negative acceleration value is obtained so that the magnitude of the specific deceleration increases as the target pedestrian's approach speed to the vehicle passage area in the vehicle width direction of the vehicle increases, and a "specific deceleration control" (second braking control) is executed to control the braking / driving force control device so that the actual acceleration of the vehicle matches the specific deceleration (steps 525, 555, and 560 in FIG. 5).

[0011] Further, the controller When the specific deceleration becomes smaller than the following acceleration while both the following cruise control and the specific deceleration control are being executed, the execution of the following cruise control is stopped (steps 535 and 540 in FIG. 5).

[0012] The device of the present invention may be configured such that, if no target vehicle is detected during execution of the following running control, the vehicle runs at a speed (set vehicle speed) set by the driver of the vehicle. If a target pedestrian is detected during execution of the following running control, specific deceleration control is executed. That is, the host vehicle decelerates according to the specific deceleration. Thereafter, when execution of the specific deceleration control ends, the host vehicle may accelerate due to the following running control. In this case, when a new target pedestrian (following target pedestrian) is detected, the running speed of the host vehicle may be relatively high at that time, or the distance to the following target pedestrian may be relatively short.

[0013] Therefore, the device of the present invention stops the execution of the following cruise control when the specific deceleration becomes smaller than the following acceleration when both the following cruise control and the specific deceleration control are executed. Therefore, the device of the present invention is more likely to be able to avoid the occurrence of an event in which the running speed of the host vehicle becomes higher than necessary or the host vehicle approaches too close to the following target pedestrian when the following target pedestrian is detected due to the execution of the following cruise control.

[0014] 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 embodiments defined by the names and / or symbols. 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]

[0015] [Figure 1] 1 is a schematic diagram of a vehicle equipped with a driving assistance device according to an embodiment of the present invention (the present assistance device). [Diagram 2] FIG. 2 is a block diagram of the support device. [Diagram 3] 11 is a diagram showing an example in which the support device executes follow-up cruise control and second braking control. FIG. [Figure 4] 5 is a time chart showing changes over time in the acceleration, following acceleration, and specific deceleration of a vehicle to be followed when following travel control and second braking control are executed. [Diagram 5] 4 is a flowchart showing a driving assistance control processing routine executed by the assistance device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (composition) Hereinafter, a driving assistance device according to an embodiment of the present invention (hereinafter also referred to as "this assistance device") will be described with reference to the drawings. This assistance device is applied to a vehicle 10 shown in FIG. 1. As can be seen from FIG. 2, which is a block diagram of this assistance device, this assistance device includes "a driving assistance ECU 21, a drive control ECU 22, and a braking control ECU 23," each of which is an electronic control unit (ECU).

[0017] The driving assistance ECU 21 includes, as its main components, a microcomputer equipped with a CPU, a non-volatile memory, and a RAM. The CPU sequentially executes a predetermined program (routine) to read data, perform numerical calculations, and output the calculation results. The non-volatile memory is composed of a ROM and a rewritable flash memory, and stores the programs executed by the CPU and look-up tables (maps) referenced when the programs are executed. The RAM temporarily stores data referenced by the CPU.

[0018] Each of the drive control ECU 22 and the brake control ECU 23 includes a microcomputer as a main element, similar to the drive assistance ECU 21. These ECUs are capable of data communication (data exchange) with each other via a CAN (Controller Area Network) 24.

[0019] In addition, these ECUs can receive output values ​​of sensors connected to other ECUs from the "other ECUs" via the CAN 24. For example, each of the drive control ECU 22 and the brake control ECU 23 can receive a vehicle speed Vs detected by a vehicle speed sensor 32 (described later) connected to the driving assistance ECU 21 from the driving assistance ECU 21 via the CAN 24. Furthermore, all or some of these ECUs may be integrated into one ECU (control unit).

[0020] Hereinafter, the driving assistance ECU 21 is also simply referred to as the ECU 21. The ECU 21 is connected to a forward camera 31, a vehicle speed sensor 32, a display 33, and a speaker .

[0021] The front camera 31 is disposed near a rearview mirror (not shown) at the top of the passenger compartment of the vehicle 10 (see FIG. 1). The front camera 31 captures a "front image" of the area in front of the vehicle 10 at every predetermined time interval ΔTc (fixed value), and outputs a signal representing the front image to the ECU 21.

[0022] The vehicle speed sensor 32 detects the vehicle speed Vs, which is the traveling speed of the vehicle 10, and outputs a signal indicative of the vehicle speed Vs to the ECU 21.

[0023] The display 33 is a liquid crystal display (LCD) disposed in a position visible to the driver within the cabin of the vehicle 10. The characters, figures, and the like displayed on the display 33 are controlled by the ECU 21.

[0024] The speaker 34 is disposed in the passenger compartment of the vehicle 10. The warning sounds, voice messages, and the like reproduced by the speaker 34 are controlled by the ECU 21.

[0025] (Drive force control) The drive control ECU 22 adjusts the drive force of the vehicle 10 by controlling the engine 41 and the transmission 42. The drive control ECU 22 is connected to various drive control sensors 43 and receives output values ​​of these sensors. The drive control sensors 43 are sensors that detect operating state quantities (parameters) of the engine 41 and operations by the driver related to drive control.

[0026] The drive control sensor 43 includes an accelerator pedal operation amount (depression amount) sensor, a shift position sensor that detects the operation state of the shift lever, a throttle valve opening sensor, an engine rotation speed sensor, an intake air amount sensor, etc. The drive control ECU 22 determines a required drive torque Frq (which is a required value of a drive torque Fd described later) based on the vehicle speed Vs and the output value of the drive control sensor 43, etc.

[0027] Furthermore, the drive control ECU 22 is connected to an engine actuator 44 including a throttle valve actuator, a fuel injection valve, etc., and controls these actuators to control the torque generated by the engine 41. The drive control ECU 22 controls the engine actuator 44 and the transmission 42 so that the drive torque Fd transmitted to the drive wheels of the vehicle 10 matches the required drive torque Frq, thereby controlling the acceleration Ac which is the amount of change in vehicle speed Vs per unit time.

[0028] Furthermore, when the drive control ECU 22 receives a "driving force control request" including the target drive torque Ftg from the ECU 21 via the CAN 24, it controls the engine actuator 44 and the transmission 42 so that the actual drive torque Fd matches the target drive torque Ftg. If the drive control ECU 22 does not receive a new drive force control request from the ECU 21 for a predetermined period of time after receiving the drive force control request, it resumes the process of controlling the acceleration Ac so that the drive torque Fd matches the requested drive torque Frq.

[0029] (Braking force control) The braking control ECU 23 controls the brake mechanism 45, which is a hydraulic friction braking device (braking mechanism) mounted on the vehicle 10. The braking control ECU 23 is connected to various braking control sensors 46 and receives output values ​​of these sensors. The braking control sensors 46 are sensors that detect state quantities used to control the brake mechanism 45 and operations by the driver related to braking control, and include a brake pedal operation amount sensor and a brake oil pressure sensor acting on the brake mechanism 45. The braking control ECU 23 determines a required braking force Brq (which is a required value of a braking force Bf described later) based on the vehicle speed Vs and the output values ​​of the braking control sensors 46, etc.

[0030] In addition, the brake control ECU 23 is connected to various brake actuators 47, which are hydraulic control actuators for the brake mechanism 45. The brake control ECU 23 controls the brake actuators 47 so that the braking force Bf, which is the total amount of friction braking force generated by each wheel of the vehicle 10, matches the required braking force Brq, thereby controlling the acceleration Ac. Note that the acceleration Ac in this case is a negative value, and the magnitude of the acceleration Ac represents the deceleration.

[0031] Furthermore, when the brake control ECU 23 receives a "braking force control request" including the target braking force Btg from the ECU 21 via the CAN 24, the brake control ECU 23 generates a braking force Bf using the brake actuator 47 so that the actual braking force Bf matches the target braking force Btg. If the brake control ECU 23 does not receive a new braking force control request from the ECU 21 for a predetermined period of time after receiving the braking force control request, the brake control ECU 23 resumes the process of controlling the brake actuator 47 so that the braking force Bf matches the required braking force Brq. Note that if the target braking force Btg is smaller than the required braking force Brq, the brake control ECU 23 controls the brake actuator 47 so that the actual braking force Bf matches the required braking force Brq.

[0032] (Driver assistance control) Next, the driving assistance control executed by the ECU 21 will be described. The driving assistance control executed by the ECU 21 includes "follow-up driving control," "first braking control," and "second braking control." The following driving control is also called adaptive cruise control (ACC). The first braking control is also called pre-crash safety (PCS). For convenience, the second braking control is also called "specific deceleration control."

[0033] First, a process of detecting (extracting) a three-dimensional object that is a target of driving support control from a forward image will be described. The three-dimensional object detected from the forward image will be hereinafter also referred to as a "detected object."

[0034] In the following description, an XY coordinate system is used with the origin at the front end of the vehicle 10 in the left-right center (see FIG. 1). The axis extending in the width direction of the vehicle 10 is the X axis, and the axis extending in the front-rear direction of the vehicle 10 is the Y axis. The X axis and the Y axis are perpendicular to each other. The X coordinate value is a positive value in the right direction relative to the traveling direction of the vehicle 10, and a negative value in the left direction relative to the traveling direction of the vehicle 10. The Y coordinate value is a positive value in the forward direction of the vehicle 10, and a negative value in the backward direction of the vehicle 10.

[0035] The ECU 21 detects (extracts) three-dimensional objects (i.e., detected objects) such as other vehicles and pedestrians based on a forward image (specifically, a signal representing the forward image) received from the forward camera 31. More specifically, the ECU 21 detects detected objects from the forward image using a well-known template matching method. For this purpose, the ECU 21 stores various "templates" corresponding to other vehicles, pedestrians, etc. in advance in a non-volatile memory.

[0036] If an area similar to one of the stored templates is included in the forward image, the ECU 21 determines that the detected object corresponding to that template (corresponding template) is included in that area. That is, in this case, the ECU 21 detects (extracts) the detected object from the forward image.

[0037] When the ECU 21 detects a detected object from the forward image, the ECU 21 acquires the type of the template corresponding to the detected object (i.e., the corresponding template) as the type of the detected object. In this embodiment, the types of the detected object (i.e., the types of the templates pre-stored in the ECU 21) include "other vehicle" and "pedestrian".

[0038] Furthermore, the ECU 21 uses a known method to acquire the left and right edge positions of the detected object relative to the vehicle 10. Each of the left and right edge positions is represented by a combination of an X coordinate value and a Y coordinate value.

[0039] The ECU 21 acquires the Y coordinate value of the detected target as the vertical position Dy. Specifically, the ECU 21 acquires the smaller value of the Y coordinate value of the left end position or the Y coordinate value of the right end position of the detected target as the vertical position Dy.

[0040] In addition, the ECU 21 obtains the X coordinate value of the detected target as the lateral position Dx. Specifically, the ECU 21 obtains the average value of the X coordinate value of the left end position and the X coordinate value of the right end position of the detected target as the lateral position Dx.

[0041] If the detected object detected in the forward image (latest image) last received by the ECU 21 from the forward camera 31 is also detected in the previously received image (i.e., the image acquired a time interval ΔTc before the latest image was acquired), the ECU 21 acquires the moving speed of the detected object. The moving speed of the detected object is represented by a combination of the longitudinal speed Vy and the lateral speed Vx.

[0042] The ECU 21 obtains the longitudinal speed Vy by dividing the "amount of change ΔDy of the longitudinal position Dy during the time interval ΔTc" by the time interval ΔTc (i.e., Vy=ΔDy / ΔTc). In addition, the ECU 21 obtains the lateral speed Vx by dividing the "amount of change ΔDx of the lateral position Dx during the time interval ΔTc" by the time interval ΔTc (i.e., Vx=ΔDx / ΔTc).

[0043] (Driver assistance control - Adaptive cruise control) Next, the following driving control will be described. When the driver of the vehicle 10 performs a predetermined operation, the ECU 21 starts the following driving control. When the following driving control starts, the ECU 21 stores the vehicle speed Vs at that time in the RAM as a set vehicle speed Vset. If there is no other vehicle (i.e., a detected object whose type is determined to be "other vehicle" and hereinafter also referred to as "vehicle to be followed") traveling ahead of the vehicle 10, the ECU 21 determines a following acceleration Af, which is the value of the acceleration Ac for matching the vehicle speed Vs with the set vehicle speed Vset.

[0044] On the other hand, if a vehicle to be followed is present, the ECU 21 determines the following acceleration Af so that the inter-vehicle distance to the vehicle to be followed becomes equal to the "target inter-vehicle distance Dtg set by a predetermined operation by the driver."

[0045] If neither the first braking control nor the second braking control is being executed, the ECU 21 sets the target acceleration Atg to a value equal to the following acceleration Af, and in addition, the ECU 21 requests the drive control ECU 22 and the braking control ECU 23 to make the actual acceleration Ac equal to the target acceleration Atg.

[0046] Generally, when the target acceleration Atg is a positive value, the ECU 21 acquires (determines) a target driving torque Ftg so that the actual acceleration Ac is equal to the target acceleration Atg, and transmits a driving force control request including the acquired target driving torque Ftg to the drive control ECU 22. When the target acceleration Atg is a negative value, the ECU 21 requests the drive control ECU 22 to reduce the driving torque Fd.

[0047] If the target acceleration Atg is a negative value and its absolute value is relatively large, the ECU 21 acquires (determines) a target braking force Btg so that the actual acceleration Ac becomes equal to the target acceleration Atg. In addition, the ECU 21 transmits a braking force control request including the acquired target braking force Btg to the brake control ECU 23, while requesting the drive control ECU 22 to set the drive torque Fd to "0".

[0048] (Driving assistance control - 1st braking control) If a detected object (specifically, another vehicle, a pedestrian, etc.) is included in the predicted travel path of the vehicle 10 (i.e., if there is a detected object whose lateral position Dx is smaller than half the vehicle width Wd (see FIG. 1) of the vehicle 10), the ECU 21 acquires (calculates) a collision time Tc which is a predicted time until the detected object collides with the vehicle 10. If the collision time Tc becomes smaller than a predetermined time threshold Tth, the ECU 21 executes a first braking control.

[0049] When the first braking control is executed, the ECU 21 transmits to the brake control ECU 23 a braking force control request including a target braking force Btg set to a value equal to "a maximum braking force Bmx, which is a maximum value of the braking force Bf that can be generated by the brake mechanism 45 in many cases." In addition, the ECU 21 transmits to the drive control ECU 22 a driving force control request in which the target driving torque Ftg is set to "0."

[0050] (Driving assistance control - Secondary braking control) The second braking control is executed to avoid a collision with a pedestrian approaching the predicted travel route of the vehicle 10. The pedestrian targeted by the second braking control (i.e., the detected target whose target type is determined to be "pedestrian" and satisfies the conditions described later) is also referred to as the "target pedestrian".

[0051] In the present embodiment, the target pedestrian is a detected target that satisfies all of the following conditions (a) to (e). Condition (a): The target type of the detected target is "pedestrian". Condition (b): The magnitude of the lateral position Dx of the detected target is greater than half of the vehicle width Wd of the vehicle 10 and less than or equal to a predetermined first distance threshold Dth1 (i.e., -Dth1 ≤ Dx < -Wd / 2, or Wd / 2 < Dx ≤ Dth1; refer to FIG. 3 described later). Condition (c): The longitudinal position Dy of the detected target is 0 or more and less than or equal to a predetermined second distance threshold Dth2 (i.e., 0 ≤ Dy < Dth2). Condition (d): The detected target is approaching in the vehicle width direction (i.e., the X-axis direction) of the vehicle 10 and the magnitude of the lateral speed Vx is less than or equal to a predetermined first speed threshold Vth1 (i.e., Dx × Vx < 0, and -Vth1 ≤ Vx ≤ Vth1). Condition (e): The detected target is approaching in the longitudinal direction (i.e., the Y-axis direction) of the vehicle 10 and the magnitude of the longitudinal speed Vy is less than or equal to a predetermined second speed threshold Vth2 (i.e., -Vth2 ≤ Vy < 0).

[0052] If a target pedestrian exists, the ECU 21 acquires (determines) a specific deceleration Ds. The specific deceleration Ds is a negative value (i.e., Ds < 0). In addition, the ECU 21 controls the drive control ECU 22 and the braking control ECU 23 so that the actual acceleration Ac matches the specific deceleration Ds.

[0053] The ECU 21 acquires the specific deceleration Ds based on the position (i.e., lateral position Dx and longitudinal position Dy) and speed (i.e., lateral velocity Vx and longitudinal velocity Vy) of the target pedestrian (i.e., the detected object) relative to the vehicle 10. The magnitude of the specific deceleration Ds increases as the lateral position Dx of the target pedestrian decreases and as the longitudinal position Dy decreases. In addition, the magnitude of the specific deceleration Ds increases as the lateral velocity Vx of the target pedestrian increases and as the longitudinal velocity Vy increases. In other words, the ECU 21 acquires the specific deceleration Ds such that the magnitude of the specific deceleration Ds increases as the magnitude of the lateral velocity Vx (i.e., the approach speed of the vehicle 10 to the predicted driving area (subject vehicle passing area) in the vehicle width direction of the vehicle 10) increases.

[0054] If the following cruise control is not being executed when the second braking control is executed (that is, when the target pedestrian is present), the ECU 21 sets the target acceleration Atg to a value equal to the specific deceleration Ds.

[0055] When the second braking control is executed during the execution of the follow-up running control and the specific deceleration Ds becomes smaller than the follow-up acceleration Af, the ECU 21 stops the follow-up running control. In this case, the ECU 21 sets the target acceleration Atg to a value equal to the specific deceleration Ds.

[0056] On the other hand, when the second braking control is executed during the execution of the following driving control, if the following acceleration Af is smaller than the specific deceleration Ds (i.e., if the "deceleration required by the following driving control" is greater than the "deceleration required by the second braking control"), the ECU 21 sets the target acceleration Atg to a value equal to the following acceleration Af.

[0057] An example in which the following driving control and the second braking control are both executed is shown in the schematic diagram of Fig. 3 and the time chart of Fig. 4. The vehicle 10 and another vehicle 51 shown in Fig. 3 are traveling in a lane 61. The other vehicle 51 is a vehicle to be followed. At the time shown in Fig. 3 (time t1 in Fig. 4, which will be described later), the inter-vehicle distance between the vehicle 10 and the other vehicle 51 is equal to the target inter-vehicle distance Dtg.

[0058] A pedestrian 52 is traveling on a sidewalk 62 adjacent to a traffic lane 61. The sidewalk 62 has a portion where its width is narrowed by an obstacle 71 on the sidewalk 62.

[0059] A curve L1 indicates a planned travel route of the pedestrian 52. As can be seen from the curve L1, the pedestrian 52 is about to approach the lane 61 in order to go around the obstacle 71.

[0060] The pedestrian 53 is located on the opposite side of the obstacle 71 to the vehicle 10. The curve L2 indicates the planned travel route of the pedestrian 53. The pedestrian 53 is also attempting to approach the lane 61 to go around the obstacle 71.

[0061] 4, a dashed line L3 indicates the change over time in the other vehicle acceleration Ao, which is the acceleration of the other vehicle 51. A curve L4 indicates the change over time in the following acceleration Af. A dashed line L5 indicates the change over time in the specific deceleration Ds.

[0062] As can be seen from the dashed line L3, in the period from "time t0 before time t1" to time t1, the other vehicle acceleration Ao is "0." That is, in this period, the traveling speed of the other vehicle 51 does not change.

[0063] In the period from time t0 to time t1, the following acceleration Af is 0. That is, in this period, the inter-vehicle distance between the vehicle 10 and the other vehicle 51 is maintained at the target inter-vehicle distance Dtg, and the vehicle speed Vs does not change.

[0064] At time t1, the driver of the other vehicle 51 starts decelerating to reduce the possibility of a collision with the pedestrian 52. That is, after time t1, the other vehicle acceleration Ao becomes a negative value. Therefore, if the vehicle 10 does not decelerate, the inter-vehicle distance between the vehicle 10 and the other vehicle 51 becomes smaller than the target inter-vehicle distance Dtg.

[0065] Therefore, at time t2, in order to maintain the inter-vehicle distance between the vehicle 10 and the other vehicle 51 at the target inter-vehicle distance Dtg, the following acceleration Af becomes a negative value. That is, the vehicle speed Vs decreases.

[0066] Furthermore, at time t3, the pedestrian 52 becomes a target pedestrian (i.e., the pedestrian 52 satisfies all of the above-mentioned conditions (a) to (e)), and thus the second braking control is initiated. That is, the ECU 21 acquires the specific deceleration Ds. In the period from time t3 to time t6 (described later), the magnitude of the specific deceleration Ds increases as the lateral position Dx and vertical position Dy of the pedestrian 52 decrease.

[0067] However, in the period from time t3 to time t4, since the following acceleration Af is smaller than the specific deceleration Ds, the ECU 21 requests the drive control ECU 22 and the brake control ECU 23 to make the actual acceleration Ac coincident with the following acceleration Af.

[0068] After that, at time t4, the specific deceleration Ds becomes smaller than the following acceleration Af, so the ECU 21 stops executing the following cruise control.

[0069] Next, at time t5, the other vehicle acceleration Ao starts to increase. More specifically, the other vehicle 51 stops decelerating because it passes beside the pedestrian 52, and then starts accelerating in a period (not shown) after time t6. Meanwhile, at time t6, the vehicle 10 passes beside the pedestrian 52, and the second braking control ends.

[0070] Here, it is assumed that the execution of the follow-up running control is not stopped at time t4. In this case, the follow-up acceleration Af during the period after time t4 is shown by the dashed line L6. In this case, however, the ECU 21 sets the target acceleration Atg to the smaller one of the follow-up acceleration Af and the specific deceleration Ds.

[0071] After time t4, the target acceleration Atg is set to a value equal to the "specific deceleration Ds smaller than the target acceleration Atg" (i.e., the second braking control is executed), and as a result, the vehicle speed Vs decreases, and as a result, the inter-vehicle distance between the vehicle 10 and the other vehicle 51 becomes larger than the target inter-vehicle distance Dtg. Therefore, in order to reduce the inter-vehicle distance between the vehicle 10 and the other vehicle 51 to the target inter-vehicle distance Dtg, the following acceleration Af increases.

[0072] After that, when the execution of the second braking control ends at time t6, the target acceleration Atg is set to a value equal to the following acceleration Af. As a result, the vehicle 10 accelerates at least during the period from time t6 to when the inter-vehicle distance between the vehicle 10 and the other vehicle 51 becomes equal to the target inter-vehicle distance Dtg.

[0073] In other words, after the vehicle 10 passes beside the pedestrian 52, the vehicle 10 starts accelerating due to the following cruise control. Therefore, when the longitudinal position Dy of the pedestrian 53 is relatively small and the pedestrian 53 appears from the obstacle 71 (more specifically, when the pedestrian 53 is extracted from the forward image and satisfies the condition of a target pedestrian), the vehicle speed Vs becomes a relatively large value.

[0074] As a result, the magnitude of the specific deceleration Ds at the time when the pedestrian 53 satisfies the condition of a target pedestrian may become a relatively large value, which may increase the deceleration of the vehicle 10. Therefore, the ECU 21 stops the execution of the following running control at the time when the specific deceleration Ds becomes smaller than the following acceleration Af.

[0075] (Specific operation) Next, a specific operation of the ECU 21 will be described. The CPU (hereinafter, simply referred to as "CPU") of the ECU 21 executes a "driving assistance control processing routine" shown in the flowchart of Fig. 5 every time a predetermined time elapses.

[0076] During execution of the following cruise control, the CPU executes a routine, not shown, to display a symbol indicating that the following cruise control is being executed on the display 33. In addition, when a situation arises in which the first braking control should be executed, the CPU executes a routine, not shown, to execute the first braking control.

[0077] At an appropriate timing, the CPU starts the process from step 500 in Fig. 5 and proceeds to step 505 to acquire target information. Specifically, the CPU extracts a detected target based on a forward image received from the forward camera 31. When a detected target is extracted, the CPU acquires the lateral position Dx, the longitudinal position Dy, the lateral velocity Vx, and the longitudinal velocity Vy of the detected target. If multiple detected targets are extracted, the CPU acquires the lateral position Dx, the longitudinal position Dy, the lateral velocity Vx, and the longitudinal velocity Vy of each of the detected targets.

[0078] Next, the CPU proceeds to step 510 to determine whether or not follow-up cruise control is being executed. If follow-up cruise control is being executed, the CPU determines "Yes" in step 510 and proceeds to step 515 to obtain the follow-up acceleration Af. Furthermore, the CPU proceeds to step 520.

[0079] On the other hand, if follow-up cruise control is not being executed, the CPU makes a “No” determination in step 510 and proceeds directly to step 520 .

[0080] The CPU determines whether or not a target pedestrian is present in step 520. Specifically, the CPU determines whether or not a detected object that satisfies all of the above-mentioned conditions (a) to (e) is present.

[0081] If a target pedestrian is present, the CPU determines "Yes" in step 520 and proceeds to step 525 to acquire a specific deceleration Ds for the target pedestrian. If multiple target pedestrians are present, the CPU acquires a specific deceleration Ds for each of the target pedestrians and selects the minimum of these values ​​as the specific deceleration Ds.

[0082] Next, the CPU proceeds to step 530 to notify the driver of the presence of the target pedestrian. Specifically, the CPU displays a symbol representing the presence of the target pedestrian on the display 33 until a predetermined time has elapsed, and also causes the speaker 34 to play a predetermined warning sound.

[0083] Furthermore, the CPU proceeds to step 535 and determines whether or not the specific deceleration Ds is smaller than the following acceleration Af. If the following cruise control is not being executed, the CPU determines "No" in step 535.

[0084] If the specific deceleration Ds is smaller than the following acceleration Af, the CPU judges "Yes" in step 535 and proceeds to step 540 to stop the following cruise control. Next, the CPU proceeds to step 545 to notify the driver of the stop of the following cruise control. Specifically, the CPU ends the display of the symbol indicating that the following cruise control is being executed, which was being displayed on the display 33. Then, the CPU proceeds to step 550.

[0085] On the other hand, if the specific deceleration Ds is equal to or greater than the following acceleration Af (or if following cruise control is not being executed), the CPU determines “No” in step 535 and proceeds directly to step 550 .

[0086] In step 550, the CPU determines whether or not at least one of the following acceleration Af and the specific deceleration Ds has been acquired. That is, the CPU determines whether or not at least one of step 515 and step 525 has been executed during the current execution of this routine.

[0087] If at least one of the following acceleration Af and the specific deceleration Ds has been acquired, the CPU determines "Yes" in step 550 and proceeds to step 555 to acquire the target acceleration Atg.

[0088] Specifically, if both the following acceleration Af and the specific deceleration Ds have been acquired, the CPU acquires the smaller of the following acceleration Af and the specific deceleration Ds as the target acceleration Atg. If either the following acceleration Af or the specific deceleration Ds has been acquired, the CPU acquires the acquired value as the target acceleration Atg. If the execution of the following driving control is stopped in step 540, the CPU acquires the specific deceleration Ds as the target acceleration Atg.

[0089] Next, the CPU proceeds to step 560 to control the acceleration Ac. Specifically, the CPU requests the drive control ECU 22 and the brake control ECU 23 to make the actual acceleration Ac coincident with the target acceleration Atg. Furthermore, the CPU proceeds to step 595 to end the processing of this routine.

[0090] On the other hand, if neither the following acceleration Af nor the specific deceleration Ds has been acquired, the CPU determines “No” in step 550 and proceeds directly to step 595 .

[0091] If the determination condition in step 520 is not met (that is, if the target pedestrian is not present), the CPU determines “No” in step 520 and proceeds directly to step 550 .

[0092] As described above, the support device executes the second braking control for a pedestrian (i.e., a target pedestrian) who is not included in the host vehicle passing area where the vehicle 10 is expected to travel (i.e., the size of the lateral position Dx is larger than half the vehicle width Wd) and who satisfies a predetermined condition. In addition, when both the following running control and the second braking control are being executed, the support device stops execution of the following running control if the specific deceleration Ds becomes smaller than the following acceleration Af.

[0093] Therefore, according to this support device, it is possible to avoid an event in which the vehicle 10 accelerates due to the following running control when the second braking control ends, and the vehicle speed Vs becomes relatively high at the time when the second braking control is executed for a newly detected target (e.g., a target pedestrian) thereafter. Meanwhile, since this support device does not immediately stop the following running control when the second braking control is started during the execution of the following running control, it is possible to extend the period during which the following running control is executed as long as possible.

[0094] Although the embodiment of the driving support device according to the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the object of the present invention. For example, the first distance threshold Dth1, the second distance threshold Dth2, the first speed threshold Vth1, and the second speed threshold Vth2 in the present embodiment are fixed values. However, some or all of these values ​​may be set to larger values ​​as the vehicle speed Vs increases.

[0095] In addition, the driving assistance ECU 21 according to the present embodiment determines that the pedestrian is not included in the area (the vehicle passing area) in which the vehicle 10 is expected to travel if the lateral position Dx of the pedestrian is larger than half the vehicle width Wd of the vehicle 10 (see condition (b)). However, the driving assistance ECU 21 may determine whether the pedestrian is included in the vehicle passing area based on a method different from the above. For example, the driving assistance ECU 21 may be configured to acquire the vehicle passing area based on the steering angle of the vehicle 10, and determine that the pedestrian is not included in the vehicle passing area if the distance between the vehicle passing area and the position of the pedestrian (i.e., the combination of the lateral position Dx and the vertical position Dy) is larger than a predetermined threshold value.

[0096] In addition, the driving assistance ECU 21 according to the present embodiment extracts (detects) a three-dimensional object included in the forward image. However, the process of extracting a three-dimensional object included in the forward image may be executed by the forward camera 31. In this case, the forward camera 31 may be configured to output to the ECU 21 the position and speed of the three-dimensional object included in the forward image relative to the vehicle 10, as well as the type of the object.

[0097] In addition, the driving assistance ECU 21 according to the present embodiment detects three-dimensional objects (specifically, a vehicle to be followed and a pedestrian to be followed, etc.) based on a forward image acquired by the forward camera 31. However, the driving assistance ECU 21 may be configured to detect three-dimensional objects based on detection information from a sensor other than the forward camera 31 (for example, a LiDAR (Light Detection and Ranging) device and a millimeter wave radar device).

[0098] In addition, the functions realized by the driving assistance ECU 21 according to the present embodiment may be realized by a plurality of ECUs. [Explanation of symbols]

[0099] 10...vehicle, 21...driving assistance ECU, 22...drive control ECU, 23...braking control ECU, 24...CAN, 31...forward camera, 32...vehicle speed sensor, 33...display, 34...speaker, 51...other vehicles, 52...pedestrian, 53...pedestrian, 61...lane, 62...sidewalk, 71...obstacle.

Claims

[Claim 1] A target detection device that detects a three-dimensional target present in a forward area of ​​a vehicle; a braking / driving force control device for controlling a driving force and a braking force of the vehicle; obtain a following acceleration, which is an acceleration required for making the inter-vehicle distance between the vehicle and a following target vehicle traveling ahead of the vehicle, equal to a target inter-vehicle distance, and execute a following travel control for controlling the braking / driving force control device so that an actual acceleration of the vehicle equals the following acceleration; when the detected three-dimensional object is present within a vehicle passing area through which the vehicle is expected to travel, and a collision time, which is an expected time until a collision between the three-dimensional object and the vehicle, becomes smaller than a predetermined time threshold, a first braking control is executed to cause the braking / driving force control device to generate a predetermined braking force for avoiding a collision between the three-dimensional object and the vehicle; executes a specific deceleration control different from the first braking control, in which, when a target pedestrian is present, the target pedestrian is one of the detected three-dimensional objects that is outside the host vehicle passing area and is approaching the host vehicle passing area, a specific deceleration which is an acceleration having a negative value is acquired such that the magnitude of the specific deceleration increases as the approach speed of the target pedestrian to the host vehicle passing area in the vehicle width direction of the vehicle increases, and the braking / driving force control device is controlled so that an actual acceleration of the vehicle coincides with the specific deceleration; when the specific deceleration becomes smaller than the following acceleration while both the following running control and the specific deceleration control are being executed, execution of the following running control is stopped. With a controller, Driving assistance device.

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