Driving assistance device

Abstract

A drive assist device executes deployment control including at least deployment of an airbag of a vehicle, if a collision index value satisfies a predetermined collision condition. The drive assist device executes brake drive force control in which drive force of the vehicle is made smaller than required drive force of a driver of the vehicle or brake force is applied to the vehicle, if the collision index value does not satisfy the collision condition and satisfies a predetermined light collision condition established at a collision degree lighter than the collision condition. Further, the longer an elapsed time is, the easier the light collision condition is established by the drive assist device. The elapsed time indicates a time elapsed since a time point at which an abnormal condition in which the driver is in an abnormal state in which normal driving is not performed is established, and the driver remains in the abnormal state. Thus, while the possibility of executing the brake drive force control in a case where the vehicle collides with a guardrail, a curbstone or the like is increased, the possibility of the driver feeling annoyed by the brake drive force control is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to a drive assist device for executing damage mitigating control for mitigating damage caused by a collision in the case where a vehicle has collided. BACKGROUND

[0002] Hitherto, a drive assist device for executing damage mitigating control in the case where a vehicle has collided is known. As the damage mitigating control, control for deploying an airbag (hereinafter referred to as "deployment control") is known.

[0003] It is desirable to execute brake drive force control as the damage mitigating control in the case where a slight collision, which is a collision of a degree lighter than the degree at which the deployment control is executed, has occurred. The brake drive force control is control for making the drive force of the vehicle smaller than the required drive force of the driver or providing a brake force to the vehicle in order to mitigate secondary damage in which the vehicle moves after a collision and further collides with another object. This brake drive force control is also sometimes referred to as "secondary damage mitigating control".

[0004] In order to make it possible to execute the brake drive force control also in the case where the vehicle has collided with a guardrail, a curbstone, or the like, it is desirable to set a threshold value for determining whether to execute the above-described brake drive force control (in other words, a threshold value used in the determination of whether a slight collision has occurred, hereinafter referred to as "slight collision threshold value") to a relatively small value.

[0005] However, when the slight collision threshold value is set to a relatively small value, there is a possibility that the brake drive force control is erroneously executed although a slight collision has not occurred in the case where the vehicle is running on a poor road or the like. Therefore, the slight collision threshold value is set to a relatively high value.

[0006] For example, a drive assist device described in Patent Literature 1 (hereinafter referred to as "conventional device") executes the brake drive force control if the driver is in a drowsy state and does not execute the brake drive force control if the driver is not in a drowsy state in the case where a collision index value, which indicates the degree of a collision, becomes equal to or greater than the slight collision threshold value (that is, in the case where a slight collision has occurred).

[0007] PRIOR ART DOCUMENT

[0008] Patent Literature 1: Japanese Patent Application Laid-Open No. 2021-112983 SUMMARY

[0009] In the conventional device, the condition that the driver is in a drowsy state is a necessary condition for executing the brake drive force control. Therefore, even if the brake drive force control is erroneously executed, since the brake drive force control alerts the attention of the driver in a drowsy state, the possibility that the driver is annoyed by the brake drive force control is low. Therefore, the above-described slight collision threshold value can be set to a relatively low value.

[0010] However, the existing device can erroneously determine that the driver is in a drowsy state even when the driver is not in the drowsy state. If the erroneous determination is made and the brake driving force control is erroneously executed, the driver is likely to feel annoyed by the brake driving force control.

[0011] The present application has been achieved in order to address the aforementioned problems. That is, one of the objects of the present application is to provide a driving assistance device that can reduce the likelihood that a driver feels annoyed by brake driving force control while increasing the likelihood that the brake driving force control is executed in a case where a vehicle collides with a guardrail, a curbstone, or the like.

[0012] The driving assistance device of the present application (hereinafter referred to as "the device of the present application") includes:

[0013] an acceleration sensor (24) configured to measure an acceleration (G) acting on a vehicle body of a vehicle (VA); and

[0014] a control unit (20, 30, 40) configured to execute, in a case where the vehicle has collided, damage mitigation control for mitigating damage caused by the collision,

[0015] the control unit is configured to:

[0016] in a case where a collision index value indicating a degree of collision of the vehicle satisfies a predetermined collision condition (step 540 "Yes"), the collision index value being an index value obtained on the basis of the acceleration, execute, as the damage mitigation control, deployment control including at least control to deploy an airbag (62) of the vehicle (step 565),

[0017] in a case where the collision index value does not satisfy the collision condition and satisfies a predetermined light collision condition established in a case of a collision of a lighter degree than the collision condition (step 535 "Yes", step 545 "Yes"), execute, as the damage mitigation control, brake driving force control to make a driving force of the vehicle smaller than a required driving force of a driver of the vehicle or to provide a braking force to the vehicle (step 550, steps 700 to 795),

[0018] the longer an elapsed time, which indicates a time elapsed since a point in time at which the abnormal condition that the driver is in an abnormal state in which normal driving is not performed is established, has passed while the driver remains in the abnormal state, the more easily the light collision condition is established (steps 620 to 640).

[0019] According to the device of the application, the longer the elapsed time that has elapsed since the time point at which the abnormal condition of the driver is maintained, the more easily the light collision condition is established, and thus the braking / driving force control is easily executed in the case where a collision of a light degree has occurred. Thus, the higher the possibility that the driver is in an abnormal state, the more the possibility that the braking / driving force control is executed in the case where a guardrail or a curbstone or the like has been collided with can be increased. Even if the braking / driving force control is erroneously executed, the braking / driving force control alerts the driver who has a high possibility of being in an abnormal state, and thus the driver has a low possibility of feeling annoyed by the braking / driving force control.

[0020] In one aspect of the device of the application,

[0021] The control unit is configured to:

[0022] In the case where the collision index value is equal to or higher than a predetermined collision threshold value (GAth) (step 540, "Yes"), the collision condition is established,

[0023] In the case where at least the first condition that the collision index value is equal to or higher than a predetermined light collision threshold value (GBth) and lower than the collision threshold value is established (step 535, "Yes"), the light collision condition is established, and the predetermined light collision threshold value is set to a value lower than the collision threshold value,

[0024] The light collision threshold value is decreased as the elapsed time is longer, and thus the light collision condition is easily established (step 620, step 625, step 635).

[0025] Thus, the longer the elapsed time, the lower the light collision threshold value, and thus the longer the elapsed time, the more the light collision condition can be easily established.

[0026] In the above aspect,

[0027] The control unit is configured to establish the light collision condition in the case where the first condition is established (step 535, "Yes") and a second condition that the magnitude of the integrated value of the collision index value is equal to or higher than a predetermined integrated threshold value is established (step 545, "Yes").

[0028] The magnitude of the integrated value of the collision index value in the case where a light collision has occurred has a tendency to be larger than the magnitude of the integrated value of the collision index value in the case where the vehicle is running on a poor road. Thus, according to the above aspect, the possibility that the light collision condition is erroneously determined to be established in the case where the vehicle is running on a poor road can be reduced.

[0029] In the above aspect,

[0030] The control unit is configured to make the light collision condition more likely to be established by making the light collision threshold value and the integration threshold value smaller as the elapsed time is longer (steps 620 to 640).

[0031] Thus, the longer the elapsed time, the smaller the light collision threshold value and the integration threshold value are made, and therefore the longer the elapsed time, the more likely the light collision condition is made to be established.

[0032] In one aspect of the device of the application,

[0033] The control unit is configured to make the abnormal condition established in a case where the driver is in a misoperation state (step 410 "Yes") in which the driver erroneously operates an acceleration operation member, which is a member operated to accelerate the vehicle, or in a case where the driver is in a drowsy state (step 310 "Yes").

[0034] When the driver is in a misoperation state or a drowsy state, the driver is highly likely not to be driving normally. The abnormal condition is made in such a case, and the longer the elapsed time from the point in time at which the abnormal condition is made, the more likely the light collision condition is made to be established, and therefore the brake / drive force control can be executed in a lighter collision, and even if the brake / drive force control is erroneously executed, the driver is less likely to feel annoyed.

[0035] Further, in the above description, in order to facilitate understanding of the application, names and / or reference numerals used in the embodiments described later are added in parentheses to the configurations of the application. However, the respective components of the application are not limited to the embodiments defined by the names and / or reference numerals. Other objects, other features, and incidental advantages of the application will be easily understood from the description of the embodiments of the application described below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a schematic system configuration diagram of a driving assistance device to which an embodiment of the application relates.

[0037] Figure 2 is an explanatory diagram of an outline of the operation of a driving assistance device to which an embodiment of the application relates.

[0038] Figure 3 is a flowchart showing a drowsy determination routine executed by a CPU of the driving assistance ECU shown in Figure 1

[0039] Figure 4 is a flowchart showing a misoperation determination routine executed by a CPU of the driving assistance ECU shown in Figure 1 ​​

[0040] Figure 5 is a flowchart showing a collision determination routine executed by the CPU of the drive assist ECU. Figure 1

[0041] Figure 6 is a flowchart showing a threshold value setting sub-routine executed by the CPU of the drive assist ECU. Figure 1

[0042] Figure 7 is a flowchart showing a 1st brake control routine executed by the CPU of the drive assist ECU. Figure 1

[0043] Figure 8 is a flowchart showing a 2nd brake control routine executed by the CPU of the drive assist ECU. Figure 1

[0044] Reference Signs

[0045] 10 drive assist device, 20 drive assist ECU, 30 drive ECU, 32a accelerator pedal, 34 drive source actuator, 34a drive source, 40 brake ECU, 44 brake actuator, 44a brake device, 60 inflator, 62 airbag. DETAILED DESCRIPTION

[0046] One embodiment of the present application relates to a drive assist device (hereinafter referred to as "the present assist device".) 10 mounted on a vehicle VA. As shown in FIG. 1, the present assist device 10 is provided with a drive assist ECU (hereinafter referred to as "DSECU".) 20, a drive ECU 30, a brake ECU 40, and a notification ECU 50. These ECUs are connected to each other in a manner capable of exchanging data (capable of communication) via a CAN (Controller Area Network) not shown. Figure 1

[0047] ECU is an abbreviation of Electronic Control Unit, and is an electronic control circuit having a microcomputer including a CPU, a ROM, a RAM, and an interface (I / F) as main constituent parts. The ECU is sometimes referred to as a "control unit", a "controller", or a "computer". The CPU realizes various functions by executing instructions (routines) stored in a memory (ROM). All or several of the above-described ECUs 20 to 50 can be combined into one ECU.

[0048] The DSECU 20 is connected to a plurality of wheel speed sensors 22, an acceleration sensor 24, and a driver seat camera 26 in a manner capable of exchanging data.

[0049] ​​​​​A wheel speed sensor 22 is provided to each wheel of the vehicle VA, and generates a pulse signal each time the corresponding wheel rotates by a predetermined angle. The DSECU 20 measures the number of pulses of the pulse signal generated by each wheel speed sensor 22 in a unit time, and acquires the rotational speed (wheel speed) of each wheel on the basis of the measured number of pulses. The DSECU 20 acquires the vehicle speed Vs representing the speed of the vehicle VA on the basis of the rotational speeds of the wheels. As one example, the average of the rotational speeds of the four wheels is acquired as the vehicle speed Vs.

[0050] An acceleration sensor 24 measures the acceleration G of the vehicle body of the vehicle VA (acceleration in the front-rear direction and acceleration in the left-right direction of the vehicle VA). The acceleration sensor 24 generates a detection signal representing the acceleration G. The DSECU 20 determines the acceleration G on the basis of the detection signal generated by the acceleration sensor 24.

[0051] A driver seat camera 26 acquires a driver seat image by capturing the scenery of a region including the position of the face of the driver of the vehicle VA when the driver is seated at the driver seat of the vehicle VA. The driver seat camera 26 transmits the driver seat image to the DSECU 20.

[0052] The DSECU 20 is connected to the accelerator pedal operation amount sensor 32 and the drive source actuator 34 in a manner enabling exchange of data.

[0053] The accelerator pedal operation amount sensor 32 measures the operation amount of the accelerator pedal 32a of the vehicle VA (the amount of depression of the accelerator pedal 32a by the driver), and generates a detection signal representing the operation amount. In the following, the operation amount of the accelerator pedal 32a will be referred to as "accelerator operation amount AP". The accelerator pedal 32a is an operation member operated by the driver in order to accelerate the vehicle VA, and is also sometimes referred to as "acceleration operation member".

[0054] The drive source actuator 34 is connected to a drive source (electric motor, internal combustion engine, etc.) 34a. The drive ECU 30 changes the operation state of the drive source 34a by controlling the drive source actuator 34. Thereby, the drive ECU 30 can adjust the driving force (driving force generated by the drive source 34a) provided to the vehicle VA. The drive ECU 30 controls the drive source actuator 34 in such a manner that the greater the accelerator operation amount AP, the greater the driving force provided to the vehicle VA.

[0055] The brake ECU 40 is connected to the brake pedal operation amount sensor 42 and the brake actuator 44 in a manner enabling exchange of data.

[0056] The brake pedal operation amount sensor 42 measures the operation amount of the brake pedal 42a of the vehicle VA (the amount of depression of the brake pedal 42a), and generates a detection signal indicative of the operation amount. The operation amount of the brake pedal 42a is referred to as "brake operation amount BP" in the following.

[0057] The brake actuator 44 is connected to a brake device 44a of the oil pressure type, which is well known. The brake ECU 40 changes the frictional braking force generated by the brake device 44a by controlling the brake actuator 44. Thus, the brake ECU 40 is able to adjust the braking force provided to the vehicle VA. The brake ECU 40 controls the brake actuator 44 in such a manner that the greater the brake operation amount BP, the greater the braking force provided to the vehicle VA.

[0058] The notification ECU 50 is connected to the display 52, the hazard warning lamp 54, and the speaker 56 in a manner that enables exchange of data.

[0059] The display 52 is, for example, a multifunctional information display, and is disposed at a position facing the driver when the driver is seated on the driver's seat. The display 52 has a misoperation display lamp and a drowsiness display lamp, neither of which is shown. The misoperation display lamp is lit in a case where it is determined that the driver is operating the accelerator pedal 32a incorrectly, and the drowsiness display lamp is lit in a case where it is determined that the driver is in a drowsy state.

[0060] The hazard warning lamp 54 is lit in a case where it is determined that the driver is in a drowsy state.

[0061] The speaker 56 emits an alarm sound in a case where it is determined that the driver is in a drowsy state.

[0062] Further, the DSECU 20 is connected to the inflator 60 in a manner that enables exchange of data.

[0063] The inflator 60 generates gas to deploy (inflate) the airbag 62 in a case where it receives the ignition signal from the DSECU 20. An appropriate number of airbags 62 are disposed at appropriate positions of the vehicle VA.

[0064] (Outline of Operation)

[0065] The present assist device 10 executes deployment control in a case where the magnitude of the acceleration G is equal to or greater than a predetermined collision threshold value GAth, which is a collision condition. The deployment control includes control to deploy the airbag 62 and brake control to provide a braking force to the vehicle VA. Further, the above acceleration G is a value indicative of the degree of collision of the vehicle VA, and is sometimes referred to as a "collision index value". The collision index value is not limited to the acceleration G, and can be a value obtained on the basis of the acceleration G. For example, the collision index value can be a value obtained by multiplying the mass of the vehicle VA by the acceleration G.

[0066] The assist device 10 determines that a light collision has occurred when the first condition and the second condition below are established in the light collision condition. In this case, the assist device 10 executes the brake control that provides the braking force to the vehicle VA. The brake control executed when the light collision condition is established is referred to as "first brake control" or "braking drive force control", and the brake control executed when the collision condition is established is referred to as "second brake control".

[0067] The brake control executed when the light collision condition is established and the deployment control executed when the collision condition is established are controls for mitigating damage at the time of collision (or after collision), and are also referred to as damage mitigation controls.

[0068] First condition: the magnitude of the acceleration G is equal to or greater than a predetermined light collision threshold value GBth and less than a collision threshold value GAth.

[0069] Second condition: the magnitude of the acceleration integral value V, which is an integral value of the acceleration G, is equal to or greater than an integral threshold value Vth.

[0070] Further, the light collision threshold value GBth is set to a value smaller than the collision threshold value GAth.

[0071] The assist device 10 determines whether or not the abnormal condition in which the driver is in an abnormal state in which the driver cannot normally drive is established. In detail, the assist device 10 determines that the abnormal condition is established when either of the following conditions C1 and C2 is established.

[0072] Condition C1: a predetermined determination time Td has elapsed while the drowsy state is maintained from the time point at which the driver is detected to be in the drowsy state (time point tl shown in FIG. 1). Figure 2 Condition C2: the determination time Td has elapsed while the state in which the accelerator pedal 32a is erroneously operated is maintained from the time point at which the driver is detected to erroneously operate the accelerator pedal 32a.

[0073] Condition C2: the determination time Td has elapsed while the state in which the accelerator pedal 32a is erroneously operated is maintained from the time point at which the driver is detected to erroneously operate the accelerator pedal 32a.

[0074] The longer the time (hereinafter referred to as "elapsed time") that has elapsed while the driver maintains the abnormal state from the time point at which the abnormal condition is established, the more easily the light collision condition is established. As one example, the longer the elapsed time, the more the assist device 10 reduces the light collision threshold value GBth and the integral threshold value Vth.

[0075] The longer the elapsed time, the higher the possibility that the driver is in the abnormal state. Further, the more easily the light collision condition is established, the higher the possibility that the first brake control is erroneously executed.

[0076] Even if the first brake control is erroneously executed in the case where the driver is in an abnormal state, the possibility that the driver feels annoyed is low according to the following reasons.

[0077] In the case where the driver is erroneously operating the accelerator pedal 32a, the vehicle VA is accelerating against the driver's intention, and therefore, even if the first brake control is executed, the possibility that the driver feels annoyed is low.

[0078] In the case where the driver is in a drowsy state, there is a possibility that the driver wakes up due to the behavior change of the vehicle VA caused by the first brake control, and the possibility that the driver feels annoyed is low.

[0079] According to the present assist device 10, the higher the possibility that the driver is in an abnormal state is, the easier the light collision condition is made to be established, and therefore, even in the case where a light collision (collision of the vehicle VA against a guardrail, a curbstone, or the like) occurs which makes the deployment control not to be executed, the possibility that the first brake control is executed is increased. Thereby, it is possible to increase the possibility that the secondary damage after the light collision is mitigated. Further, when the light collision condition is easily established, the possibility that the first brake control is erroneously executed is increased. However, even if the first brake control is erroneously executed, since the possibility that the driver is in a specific state is high, the possibility that the driver feels annoyed with the first brake control is low.

[0080] (Working Example)

[0081] Reference Figure 2 A working example of the present assist device 10 will be described.

[0082] <Time point t1>

[0083] At the time point t1, the present assist device 10 detects that the driver is in a drowsy state based on the driver's seat image, and warns the driver. In detail, the present assist device 10 causes the drowsy display lamp of the display 52 to be lit, causes the hazard warning lamp 54 to be lit, and causes the speaker 56 to emit a warning sound.

[0084] <Time point t2>

[0085] The time point t2 is a time point after the determination time Td elapses from the time point t1 while the driver remains in the drowsy state. At the time point t2, the present assist device 10 determines that the above condition C1 is established, and determines that the abnormal condition is established.

[0086] In the normal time when the abnormal condition does not exist, the assist device 10 sets the slight collision threshold value Gbth to "GBthl" and sets the integration threshold value Vth to "Vthl". At the time point t2, the assist device 10 sets the slight collision threshold value Gbth to "GBth2" and sets the integration threshold value Vth to "Vth2". "GBth2" is a value smaller than "GBthl", and "Vth2" is a value smaller than "Vthl".

[0087] <Time point t3>

[0088] The assist device 10 sets the slight collision threshold value Gbth to "GBth3" and sets the integration threshold value Vth to "Vth3" at the time point t3 which is a certain time Tc after the time point t2 when the abnormal condition exists. "GBth3" is a value smaller than "GBth2", and "Vth3" is a value smaller than "Vth2".

[0089] <Time point t4>

[0090] At the time point t4, the vehicle VA collides with the guard rail GR, the acceleration G becomes equal to or greater than the slight collision threshold value GBth3, and the acceleration integration value V becomes equal to or greater than the integration threshold value Vth3. At the time point t4, the assist device 10 determines that the slight collision condition exists, and executes the first brake control.

[0091] For example, assume that the acceleration G at the time point t4 is equal to or greater than GBth3 and smaller than GBth2, and the integration value at the time point t4 is equal to or greater than Vth3 and smaller than Vth2. The assist device 10 can determine the collision of the vehicle VA with the guard rail GR at the time point t4 as a slight collision by making the slight collision condition more likely to exist as the elapsed time is longer, and can execute the first brake control.

[0092] (Detailed operation)

[0093] <Drowsiness determination routine>

[0094] The CPU of the DSECU 20 (hereinafter, unless otherwise specified, the CPU of the DSECU 20) executes the drowsiness determination routine represented by the flowchart in the CPU of the DSECU 20 each time a predetermined time elapses. Figure 3

[0095] Therefore, when the predetermined timing occurs, the CPU starts the process from step 300 of the drowsiness determination routine, proceeds to step 305, and determines whether the value of the drowsiness flag XC1 is "0". Figure 3

[0096] ​​The value of the drowsiness flag XC1 is set to "1" when the condition C1 described above is satisfied (see step 315), and is set to "0" when it is determined that the driver has recovered from the drowsy state to the normal state (see step 330). Further, in an initial routine executed by the CPU when the not-illustrated ignition switch is changed from the off position to the on position, the value of the drowsiness flag XC1 is set to "0".

[0097] When the value of the drowsiness flag XC1 is "0", the CPU determines "Yes" in step 305, and proceeds to step 310. In step 310, the CPU determines whether the drowsy state has continued for the determination time Td or more (i.e., whether the condition C1 described above is satisfied) based on the driver's seat image.

[0098] In detail, the CPU detects the drowsy state when the state in which the driver has his eyes closed has continued for a predetermined time or more. Also, the CPU determines whether the drowsy state has continued for the determination time Td from the detection time point. Further, the CPU starts the lighting of the drowsy display lamp described above, the lighting of the hazard warning lamp 54, and the sounding of the alarm sound when the drowsy state is detected.

[0099] When the drowsy state has not continued for the determination time Td or more, the CPU determines "No" in step 310, and proceeds to step 395 to temporarily end the routine.

[0100] When the drowsy state has continued for the determination time Td or more, the CPU determines "Yes" in step 310, and proceeds to step 315. In step 315, the CPU sets the value of the drowsiness flag XC1 to "1", and sets the value of the drowsy timer TMC1 to "0". Then, the CPU proceeds to step 395 to temporarily end the routine.

[0101] The drowsy timer TMC1 is a timer that counts the elapsed time from the time point at which the condition C1 described above is satisfied.

[0102] On the other hand, when the CPU proceeds to step 305 and the value of the drowsiness flag XC1 is "1", the CPU determines "No" in step 305, and proceeds to step 320. In step 320, the CPU determines whether the state in which the driver has his eyes open (hereinafter referred to as the "open eyes state") has continued for a predetermined time or more.

[0103] When the open eyes state has not continued for the predetermined time or more, the CPU determines "No" in step 320, and proceeds to step 325. In step 325, the CPU adds "1" to the value of the drowsy timer TMC1, and proceeds to step 395 to temporarily end the routine.

[0104] In the case where the open-eye state continues for more than the predetermined time, the CPU determines YES in step 320, and proceeds to step 330. In step 330, the CPU sets the value of the doze flag XCl to "0", and sets the value of the doze timer TMC1 to "0". Then, the CPU proceeds to step 395, and temporarily ends the present routine.

[0105] <Maloperation determination routine>

[0106] The CPU executes the maloperation determination routine represented by the flowchart in the main routine every time a predetermined time elapses. Figure 4

[0107] Therefore, when the predetermined time elapses, the CPU starts processing from step 400 of the main routine, proceeds to step 405, and determines whether the value of the maloperation flag XC2 is "0". Figure 4

[0108] The value of the maloperation flag XC2 is set to "1" in the case where the above condition C2 is satisfied (see step 415), and is set to "0" in the case where it is determined that the maloperation of the accelerator pedal 32a has not been performed (see step 430). Further, in the above initial routine, the value of the maloperation flag XC2 is set to "0".

[0109] In the case where the value of the maloperation flag XC2 is "0", the CPU determines YES in step 405, and proceeds to step 410. In step 410, the CPU determines whether the maloperation of the accelerator pedal 32a has continued for more than the determination time Td, on the basis of the accelerator operation amount AP.

[0110] In detail, the CPU detects the condition that the maloperation of the accelerator pedal 32a has been performed in the case where the accelerator operation amount AP becomes more than a predetermined first operation amount threshold value APthl within a predetermined time from the point in time at which the accelerator operation speed APV becomes more than a predetermined speed threshold value APVth. Further, the CPU determines whether the accelerator operation amount AP does not become "a predetermined second operation amount threshold value APth2 which is set to a value smaller than the first operation amount threshold value APthl" and more than the determination time Td from the detection point in time of the maloperation of the accelerator pedal 32a.

[0111] In the case where the maloperation of the accelerator pedal 32a has not continued for more than the determination time Td, the CPU determines NO in step 410, and proceeds to step 495, and temporarily ends the present routine.

[0112] ​​On the other hand, if the erroneous operation of the accelerator pedal 32a continues for more than the determination time Td, the CPU determines "yes" in step 410 and proceeds to step 415. In step 415, the CPU sets the value of the erroneous operation flag XC2 to "1" and sets the value of the erroneous operation timer TMC2 to "0". Then, the CPU proceeds to step 495 and temporarily terminates this routine.

[0113] The misoperation timer TMC2 is a timer that counts the elapsed time since the point when the above condition C2 is met.

[0114] If the CPU enters step 405 and the error flag XC2 is set to "1", the CPU determines "No" in step 405 and proceeds to step 420. In step 420, the CPU determines whether the accelerator operation quantity AP is below the second operation quantity threshold APth2.

[0115] If the accelerator operation amount AP is greater than the second operation amount threshold APth2, the CPU determines that the erroneous operation of the accelerator pedal 32a is still ongoing. In this case, the CPU determines "No" in step 420 and proceeds to step 425. In step 425, the CPU adds "1" to the value of the erroneous operation timer TMC2, proceeds to step 495, and temporarily terminates this routine.

[0116] If the accelerator operation quantity AP is below the second operation quantity threshold APth2, the CPU determines that the misoperation of the accelerator pedal 32a has ended. In this case, the CPU determines "yes" in step 420 and proceeds to step 430. In step 430, the CPU sets the value of the misoperation flag XC2 to "0" and sets the value of the misoperation timer TMC2 to "0". Then, the CPU proceeds to step 495 and temporarily terminates this routine.

[0117] Collision Detection Routine

[0118] The CPU executes at predetermined intervals. Figure 5 The collision determination routine is represented by a flowchart.

[0119] Therefore, when the scheduled time is reached, the CPU starts from... Figure 5 Step 500 begins processing, proceeding to step 505, where it is determined whether the value of the collision flag Xc is "0".

[0120] The value of the collision flag Xc is set to "1" in the event of a collision (see step 560), and set to "0" if the termination condition of the second braking control (described later) is met (see...). Figure 8 (See step 825 shown.) Furthermore, in the initial routine described above, the value of the collision flag Xc is set to "0".

[0121] In the case where the value of the collision flag Xc is "0", the CPU determines "Yes" in step 505, and sequentially executes steps 510 to 520.

[0122] Step 510: The CPU determines the acceleration G based on the detection signal from the acceleration sensor 24.

[0123] Step 515: The CPU obtains the acceleration integral value V by integrating the acceleration G.

[0124] This integration processing is described in paragraphs 0044 to 0047 of Japanese Patent Application Publication No. 2021-112983, and thus a brief explanation will be given below.

[0125] The CPU obtains the integral value of the acceleration G from the start timing to the end timing in the following as the acceleration integral value V.

[0126] The start timing is a timing at which the interval integral value of the acceleration G becomes a predetermined 1st integral threshold value or more. The interval integral value is an integral value of the acceleration G in a predetermined interval width.

[0127] The end timing is a timing of an earlier one of a timing at which the interval integral value becomes a predetermined 2nd integral threshold value or less after a predetermined 1st set time has elapsed and a timing at which the start timing has elapsed after a predetermined 2nd set time has elapsed. The 2nd set time is set to be longer than the 1st set time.

[0128] Step 520: The CPU determines whether the values of the drowsiness flag Xc1 and the misoperation flag Xc2 are both "0".

[0129] In the case where the values of the drowsiness flag Xc1 and the misoperation flag Xc2 are both "0", the CPU determines "Yes" in step 520, and sequentially executes steps 525 to 535.

[0130] Step 525: The CPU sets the light collision threshold value GBth to "GBth1".

[0131] Step 530: The CPU sets the integral threshold value Vth to "Vth1".

[0132] Step 535: The CPU determines whether the magnitude of the acceleration G is the light collision threshold value GBth or more and less than the collision threshold value GAth.

[0133] In the case where the magnitude of the acceleration G is less than the light collision threshold value GBth or is the collision threshold value GAth or more, the CPU determines "No" in step 535, and proceeds to step 540. In step 540, the CPU determines whether the magnitude of the acceleration G is the collision threshold value GAth or more.

[0134] In the case where the magnitude of the acceleration G is smaller than the collision threshold value Gath, the CPU determines "NO" in step 540, and proceeds to step 595 to temporarily end the routine.

[0135] In the case where the magnitude of the acceleration G is equal to or greater than the light collision threshold value GBth and smaller than the collision threshold value Gath when the CPU proceeds to step 535, the CPU determines "YES" in step 535, and proceeds to step 545.

[0136] In step 545, the CPU determines whether the magnitude of the acceleration integral value V is equal to or greater than the integral threshold value Vth.

[0137] In the case where the magnitude of the acceleration integral value V is smaller than the integral threshold value Vth, the CPU determines that no light collision has occurred. In this case, the CPU determines "NO" in step 545, and proceeds to step 595 to temporarily end the routine.

[0138] In the case where the magnitude of the acceleration integral value V is equal to or greater than the integral threshold value Vth, the CPU determines that a light collision has occurred. In this case, the CPU determines "YES" in step 545, and proceeds to step 550. In step 550, the CPU sets the value of the light collision flag XLc to "1", and proceeds to step 595 to temporarily end the routine.

[0139] In the case where the magnitude of the acceleration G is equal to or greater than the collision threshold value GAth when the CPU proceeds to step 540, the CPU determines that a collision has occurred. In this case, the CPU determines "YES" in step 540, and sequentially executes step 560 and step 565.

[0140] Step 560: The CPU sets the value of the collision flag Xc to "1".

[0141] Step 565: The CPU sends an ignition signal to the inflator 60.

[0142] As described above, the inflator 60 causes the airbag 62 to deploy when receiving the ignition signal.

[0143] Then, the CPU proceeds to step 595 to temporarily end the routine.

[0144] In the case where the value of at least one of the doze flag XCl and the misoperation flag XC2 is "1" when the CPU proceeds to step 520, the CPU determines "NO" in step 520, and proceeds to step 570 to execute the threshold value setting subroutine. Then, the CPU proceeds to the processing after step 535.

[0145] <Threshold Value Setting Subroutine>

[0146] The CPU proceeds to step 535 when the value of the doze flag XCl is "0" and the value of the misoperation flag XC2 is "0" when the CPU proceeds to step 520.Figure 5 The step 570 shown is followed by a step 575 in which the CPU determines whether the value of the drowsiness flag XCl is "1". Figure 6 The processing shown in the step 600 is started, and a step 605 is entered. In the step 605, the CPU determines whether the values of both the drowsiness flag XCl and the misoperation flag XC2 are "1".

[0147] In the case where the value of at least one of the drowsiness flag XCl and the misoperation flag XC2 is "0", the CPU determines "No" in the step 605, and a step 610 is entered. In the step 610, the CPU determines "Yes" in the step 610 in the case where the value of the drowsiness flag XCl is "1", and a step 615 and a step 620 are sequentially executed.

[0148] Step 615: The CPU sets the value of the elapsed time timer TM to the value of the drowsiness timer TMC1.

[0149] Step 620: The CPU determines whether the value of the elapsed time timer TM is below a predetermined certain time threshold Tcth. The certain time threshold Tcth is set so that the value of the elapsed time timer TM reaches the certain time threshold Tcth when the elapsed time reaches a certain time Tc.

[0150] In the case where the value of the elapsed time timer TM is below the certain time threshold Tcth, the CPU determines "Yes" in the step 620, and a step 625 and a step 630 are sequentially executed.

[0151] Step 625: The CPU sets the light collision threshold GBth to "GBth2".

[0152] Step 630: The CPU sets the point threshold Vth to "Vth2".

[0153] Then, the CPU enters a step 695 and temporarily ends the present routine, and enters the step 535 shown. Figure 5

[0154] In the case where the value of the elapsed time timer TM is larger than the certain time threshold Tcth when the CPU enters the step 620, the CPU determines "No" in the step 620, and a step 635 and a step 640 are sequentially executed.

[0155] Step 635: The CPU sets the light collision threshold GBth to "GBth3".

[0156] Step 640: The CPU sets the point threshold Vth to "Vth3".

[0157] Then, the CPU enters the step 695 and temporarily ends the present routine, and enters the step 535 shown. Figure 5

[0158] ​​In the case where the value of the drowsy flag XCl is "0" when the CPU enters step 610, since the determination in step 520 shown in Fig. 5 is "No", the value of the misoperation flag XC2 is "1". In this case, the CPU determines "No" in step 610, and enters step 645. In step 645, the CPU sets the value of the elapsed time timer TM to the value of the misoperation timer TMC2. Then, the CPU enters the processing after step 620. Figure 5

[0159] In the case where the values of the drowsy flag XCl and the misoperation flag XC2 are both "1" when the CPU enters step 605, the CPU determines "Yes" in step 605, and enters step 650.

[0160] In step 650, the CPU determines whether the value of the drowsy timer TMC1 is equal to or greater than the value of the misoperation timer TMC2.

[0161] In the case where the value of the drowsy timer TMC1 is equal to or greater than the value of the misoperation timer TMC2, the CPU determines "Yes" in step 650, and sets the value of the elapsed time timer TM to the value of the drowsy timer TMC1 in step 615. Then, the CPU enters the processing after step 620.

[0162] In the case where the value of the drowsy timer TMC1 is less than the value of the misoperation timer TMC2, the CPU determines "No" in step 650, and sets the value of the elapsed time timer TM to the value of the misoperation timer TMC2 in step 645. Then, the CPU enters the processing after step 620.

[0163] <1st Brake Control Routine>

[0164] The CPU executes the 1st brake control routine shown by the flowchart in Fig. 6 every time a predetermined time elapses. Figure 7

[0165] Therefore, when it becomes the predetermined timing, the CPU starts the processing from step 700 in Fig. 6, enters step 705, and determines whether the value of the slight collision flag XLc is "1". Figure 7

[0166] In the case where the value of the slight collision flag XLc is "0", the CPU determines "No" in step 705, enters step 795, and temporarily ends the routine.

[0167] In the case where the value of the slight collision flag XLc is "1", the CPU determines "Yes" in step 705, and enters step 710.

[0168] In step 710, the CPU determines whether the end condition of the 1st brake control is satisfied.​​​

[0169] More specifically, the CPU determines that the above termination condition is met if any one of the following conditions D1 to D3 is met.

[0170] Condition D1: The driver recovers from drowsiness and the value of the drowsiness indicator XC1 changes from "1" to "0".

[0171] Condition D2: The erroneous operation of the accelerator pedal 32a ends and the value of the erroneous operation flag XC2 changes from "1" to "0".

[0172] Condition D3: Vehicle speed Vs becomes "0km / h".

[0173] If none of the above conditions D1 to D3 are met, the CPU determines "no" in step 710 and executes steps 715 and 720 in sequence.

[0174] Step 715: The CPU sets the target acceleration Gtgt to the predetermined first deceleration Gd1 (<0).

[0175] Step 720: Send a deceleration command, including the target acceleration Gtgt, to the drive ECU 30 and brake ECU 40.

[0176] Upon receiving a deceleration command, the drive ECU 30 and brake ECU 40 control the drive source actuator 34 and brake actuator 44 respectively, so that the longitudinal component Gx of the vehicle's acceleration G is consistent with the first deceleration Gd1 mentioned above.

[0177] Then, the CPU proceeds to step 795 and temporarily terminates this routine.

[0178] If any one of the conditions D1 to D3 is met, the CPU determines "yes" in step 710 and proceeds to step 725. In step 725, the CPU sets the value of the light collision flag XLc to "0". Therefore, if any one of the conditions D1 to D3 is met, the CPU does not send a deceleration command, and the first braking control ends.

[0179] Then, the CPU proceeds to step 795 and temporarily terminates this routine.

[0180] <Second Braking Control Routine>

[0181] The CPU executes at predetermined intervals. Figure 8 The second braking control routine is represented by a flowchart.

[0182] Therefore, when the scheduled time is reached, the CPU starts from... Figure 8The process starts at step 800, and proceeds to step 805, where it is determined whether the value of the collision flag Xc is "1".

[0183] When the value of the collision flag Xc is "0", the CPU determines "No" at step 805, and proceeds to step 895 to temporarily end this routine.

[0184] When the value of the collision flag Xc is "1", the CPU determines "Yes" at step 805, and proceeds to step 810. At step 810, the CPU determines whether the end condition of the 2nd brake control is satisfied.

[0185] More specifically, the CPU determines that the end condition is satisfied when the above condition D3 is satisfied.

[0186] When the above condition D3 is not satisfied, the CPU determines "No" at step 810, and sequentially executes steps 815 and 820.

[0187] Step 815: The CPU sets the target acceleration Gtgt to a predetermined 2nd deceleration Gd2 (<0). Further, the 2nd deceleration Gd2 is set to a negative value smaller than the 1st deceleration Gdl.

[0188] Step 820: A deceleration command including the target acceleration Gtgt is sent to the drive ECU 30 and the brake ECU 40.

[0189] Then, the CPU proceeds to step 895 to temporarily end this routine.

[0190] When the above condition D3 is satisfied, the CPU determines "Yes" at step 810, and proceeds to step 825. At step 825, the CPU sets the value of the collision flag Xc to "0". Thus, when the above condition D3 is satisfied, the CPU does not send a deceleration command, and the 2nd brake control ends.

[0191] Then, the CPU proceeds to step 895 to temporarily end this routine.

[0192] According to the above, when a slight collision occurs, the value of the slight collision flag XLc is set to "1", and the 1st brake control is executed. On the other hand, when a collision occurs, the value of the collision flag Xc is set to "1", and the deployment control (deployment of the airbag and the 2nd brake control) is executed. When the driver is in an abnormal state, the longer the elapsed time from the point in time at which the driver became in an abnormal state, the smaller the values of the threshold values (the slight collision threshold value GBth and the integration threshold value Vth) used in the determination of a slight collision (in other words, the threshold values are set in such a manner that the longer the elapsed time, the easier the slight collision condition is satisfied).

[0193] Thus, the possibility of executing the first brake control in a case where the vehicle collides with a guardrail, a curbstone, or the like can be increased, and even in a case where the first brake control is erroneously executed, the possibility of feeling annoyed by the first brake control can be reduced.

[0194] The present application is not limited to the foregoing embodiment, and various modifications thereof can be employed.

[0195] (First Modification)

[0196] The driving assistance device 10 according to the present modification executes driving force suppression control instead of the first brake control in a case where a slight collision occurs. The driving force suppression control is control that suppresses the driving force generated by the drive source 34a to be a driving force smaller than the "required driving force as the driving force based on the accelerator operation amount AP". The driving force suppression control can also be control that causes the drive source 34a to generate a threshold driving force in a case where the required driving force is equal to or greater than the threshold driving force (i.e., control that limits the driving force generated by the drive source 34a so as not to exceed the threshold driving force).

[0197] The first brake control and the above-described driving force suppression control are control of the braking force and the driving force of the vehicle VA, and are thus also referred to as "braking / driving force control".

[0198] Further, the present assistance device 10 can also execute the above-described driving force suppression control instead of the second brake control in a case where a collision occurs.

[0199] (Second Modification)

[0200] The present assistance device 10 according to the present modification determines that the slight collision condition is established in a case where the above-described second condition is not established but the above-described first condition is established.

[0201] However, when the slight collision condition is determined to be established in a case where both the first condition and the second condition are established, the possibility of erroneously determining that a slight collision has occurred in a case where the vehicle VA is running on a rough road can be reduced. This is because the magnitude of the acceleration integral value V in a case where a slight collision actually occurs has a tendency to be greater than the magnitude of the acceleration integral value V in a period during which the vehicle VA is running on a rough road.

[0202] (Third Modification)

[0203] In the above-described embodiment, the slight collision threshold value GBth and the integral threshold value Vth are made smaller than in normal times at the time point (time point t2 shown in FIG. 12) at which the abnormal condition is established, and at a time point (time point t3 shown in FIG. 12) after a certain time Tc has elapsed from the time point at which the abnormal condition is established. Figure 2 Figure 3 (Third Modification)

[0203] In the above-described embodiment, the slight collision threshold value GBth and the integral threshold value Vth are made smaller than in normal times at the time point (time point t2 shown in FIG. 12) at which the abnormal condition is established, and at a time point (time point t3 shown in FIG. 12) after a certain time Tc has elapsed from the time point at which the abnormal condition is established. Figure 2 Figure 3 (Third Modification)

[0203] In the above-described embodiment, the slight collision threshold value GBth and the integral threshold value Vth are made smaller than in normal times at the time point (time point t2 shown in FIG. 12) at which the abnormal condition is established, and at a time point (time point t3 shown in FIG. 12) after a certain time Tc has elapsed from the time point at which the abnormal condition is established. Figure 2 Figure 3The time point t3) shown further reduces the light collision threshold value GBth and the integration threshold value Vth. In this modification, the light collision threshold value GBth and the integration threshold value Vth can also be reduced by a predetermined value each time a certain time Tc elapses from the time point at which the abnormal condition is established.

[0204] (4th Modification)

[0205] In the above embodiment, the light collision threshold value GBth and the integration threshold value Vth are reduced the longer the elapsed time, thereby making it easier for the light collision condition to be established, but it is not limited to the above example. For example, either one of the light collision threshold value GBth and the integration threshold value Vth can be reduced the longer the elapsed time.

[0206] (5th Modification)

[0207] The driving assistance device 10 according to the present modification can determine that the light collision condition is established when the first multiplication value obtained by multiplying the acceleration G by the first weight coefficient a is equal to or greater than the light collision threshold value GBth and the second multiplication value obtained by multiplying the acceleration integration value V by the second weight coefficient β is equal to or greater than the integration threshold value Vth. In this case, at least one of the first weight coefficient a and the second weight coefficient β can be increased the longer the elapsed time, thereby making it easier for the light collision condition to be established.

[0208] (6th Modification)

[0209] The driving assistance device 10 according to the present modification does not perform the second brake control but performs deployment of the airbag 62 in the case where a collision has occurred.

[0210] (7th Modification)

[0211] The driving assistance device 10 can be mounted on a vehicle such as an engine automobile, a hybrid vehicle (HEV: Hybrid Electric Vehicle), a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle), a fuel cell vehicle (FCEV: Fuel Cell Electric Vehicle), and an electric vehicle (BEV: Battery Electric Vehicle).

Claims

1. A driving assistance device, comprising: An acceleration sensor configured to measure the acceleration acting on the vehicle body; and The control unit is configured to perform damage mitigation control to reduce damage caused by the collision in the event of a collision. The control unit is configured as follows: If a collision index value, representing the severity of a collision with the vehicle, meets predetermined collision conditions, deployment control is executed as damage mitigation control. The collision index value is based on the acceleration. The deployment control includes at least control that deploys the vehicle's airbags. If the collision index value does not meet the collision conditions, but a predetermined minor collision condition that is less severe than the collision conditions is met, then braking drive force control is performed to make the driving force of the vehicle less than the driving force required by the driver of the vehicle, or to provide braking force to the vehicle, as the damage mitigation control. The longer the elapsed time, the easier it is for the minor collision condition to be met. The elapsed time refers to the time that has elapsed since the abnormal condition of the driver not driving normally was met, and the driver has maintained the abnormal state. The control unit is configured as follows: If the collision index value is above a predetermined collision threshold, the collision condition is met. The light collision condition is met if the first condition is met (that the collision index value is at least above and below a predetermined light collision threshold) and the second condition is met (that the integral value of the collision index value is above a predetermined integral threshold). The predetermined light collision threshold is set to a value smaller than the collision threshold. The control unit is configured to decrease the minor collision threshold and the integral threshold as the elapsed time increases, thereby making it easier for the minor collision condition to be met. The control unit is configured to cause the abnormal condition to be met when the driver is in a state of erroneous operation of the acceleration control component or when the driver is drowsy. The acceleration control component is a component that is operated to accelerate the vehicle.

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