Vehicle control system

Abstract

The present invention provides a vehicle control device that can reduce the likelihood of an increased risk of collision even if the driver is late in recognizing the collision warning when another warning is activated. [Solution] When the collision warning condition is met, which is that the risk of the vehicle colliding with an object is above the warning threshold, the vehicle control device issues a collision warning to reduce the risk of collision. If another warning other than the collision warning is issued, the vehicle control device relaxes the collision warning condition compared to when no other warning is issued.

Description

Technical Field

[0004] , , ,

[0005] , ,

[0001] The present invention relates to a vehicle control device configured to issue a collision warning for reducing a collision risk when a collision warning condition that the collision risk of a vehicle colliding with an object has reached or exceeded a warning threshold is satisfied.

Background Art

[0002] Conventionally, a vehicle control device that issues a collision warning when a collision warning condition that the collision risk has reached or exceeded a warning threshold is satisfied is known. For example, a vehicle control device described in Patent Document 1 (hereinafter referred to as the "conventional device") sets priorities among an attention warning, a lane departure warning, a collision warning, and a failure warning, and activates a warning based on the priorities. The conventional device can prevent multiple warnings from being issued simultaneously.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] If a driver does not recognize a collision warning, the collision risk increases. Therefore, a vehicle control device that gives priority to a collision warning over other warnings has been studied. Even if such a device switches from another warning to a collision warning when the collision warning condition is satisfied while another warning is being activated, the driver may not notice the switch to the collision warning and may be delayed in recognizing the collision warning. Since the time from when the collision warning is issued until the vehicle collides with an object is relatively short, there is a possibility that the collision risk has already become high by the time the driver recognizes the collision warning late.

[0005] This invention was made to address the aforementioned problems. Specifically, one of the objectives of this invention is to provide a vehicle control device that can reduce the possibility of an increased risk of collision even if the driver is late in recognizing the collision warning when another warning is activated.

[0006] The vehicle control device of the present invention (hereinafter referred to as "the present invention device") is configured to issue a collision warning to reduce the collision risk (step 340) when a collision warning condition is met, which is that the collision risk of a vehicle colliding with an object is equal to or greater than a warning threshold (step 330 "Yes"). The vehicle control device is configured such that, when another warning different from the collision warning is issued, it relaxes the collision warning conditions compared to when the other warning is not issued (step 345). Vehicle control system.

[0007] If a collision warning is issued while other warnings are active, the driver may be slow to recognize the collision warning. This delay in recognition could mean that by the time the driver recognizes the warning, the risk of collision may have already increased significantly. The present invention relaxes the collision warning conditions when other warnings are active compared to when no other warnings are active. This reduces the possibility that the risk of collision may have already increased by the time the driver recognizes the warning, even if the driver's recognition of the collision warning is delayed due to other warnings. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a vehicle control device according to an embodiment of the present invention. [Figure 2] This is an explanatory diagram illustrating the general operation of a vehicle control device according to an embodiment of the present invention. [Figure 3] Figure 1 is a flowchart of the collision warning determination routine executed by the CPU of the ECU. [Figure 4]Figure 1 is a flowchart of the vehicle control decision routine executed by the CPU of the ECU. [Figure 5] Figure 1 shows a flowchart of the collision avoidance judgment subroutine executed by the CPU of the ECU. [Figure 6] Figure 1 is a flowchart of the gaze detection subroutine executed by the CPU of the ECU. [Modes for carrying out the invention]

[0009] As shown in Figure 1, the vehicle control device according to this embodiment (hereinafter referred to as "this device 10") is applied to a vehicle VA and comprises the components shown in Figure 1.

[0010] In this specification, "ECU20" is an electronic control unit comprising a microcomputer as its main component. ECU20 is also referred to as a control unit, controller, and computer. The microcomputer includes a CPU (processor), ROM, RAM, and interfaces, etc. The functions realized by ECU20 may be realized by multiple ECUs.

[0011] Camera 22 acquires image data by photographing the scenery in front of the vehicle VA. Millimeter-wave radar 24 acquires radar data by receiving reflected waves that are reflected by an object from millimeter waves transmitted in front of the vehicle VA. The radar data includes the position of the object relative to the vehicle VA and the relative velocity Vr of the object relative to the vehicle VA. Driver camera 26 acquires driver image data by photographing the area around the face of the driver seated in the driver's seat of the vehicle VA. ECU 20 acquires image data, radar data, and driver image data from camera 22, millimeter-wave radar 24, and driver camera 26, respectively.

[0012] The vehicle speed sensor 27 measures the vehicle speed Vs, which represents the speed of the vehicle VA. The acceleration sensor 28 measures the acceleration G of the vehicle VA. The acceleration operation amount sensor 30 measures the acceleration operation amount AP, which represents the amount of depression (operation amount) of the accelerator pedal (acceleration operator) (not shown) of the vehicle VA. The deceleration operation amount sensor 32 measures the deceleration operation amount BP, which represents the amount of depression (operation amount) of the brake pedal (deceleration operator) (not shown) of the vehicle VA. The steering angle sensor 34 measures the steering angle θ of the steering wheel (not shown) of the vehicle VA. Note that the steering angle θ is "0deg" when the steering wheel is in the neutral position. When the steering wheel is rotated to the left from the neutral position, the steering angle θ is a positive value, and when the steering wheel is rotated to the right from the neutral position, the steering angle θ is a negative value.

[0013] The ECU20 acquires measurements from the vehicle speed sensor 27, acceleration sensor 28, acceleration operation amount sensor 30, deceleration operation amount sensor 32, and steering angle sensor 34.

[0014] The powertrain actuator 40 modifies the driving force generated by the vehicle VA's drive system (e.g., internal combustion engine and / or electric motor). The brake actuator 42 controls the braking force applied to the vehicle VA's wheels. The steering motor 44 is incorporated into the steering mechanism 46. The steering mechanism 46 is a mechanism for steering the steering wheels in response to the operation of the steering wheel. Furthermore, the steering motor 44 generates an automatic steering torque in the steering mechanism 46 to change the steering angle of the steering wheels in response to instructions from the ECU 20.

[0015] The display device 48 displays collision warning display elements, which will be described later. The speaker 50 outputs a collision warning sound, which will be described later.

[0016] The ECU20 recognizes objects in front of the vehicle VA based on image data and radar data. The ECU20 acquires the TTC (Time To Collision), which represents the time it takes for the vehicle VA to collide with an object. The TTC is a value that represents the collision risk of the vehicle VA colliding with an object. A smaller TTC value means a higher collision risk.

[0017] When the collision warning condition that the TTC is less than or equal to the warning threshold time Tal is satisfied, the ECU 20 issues a collision warning. The collision warning condition is a condition that is satisfied when the collision risk becomes greater than or equal to the warning threshold value.

[0018] In the collision warning, the ECU 20 displays a collision warning display element on the display device 48 and outputs a collision warning sound from the speaker 50. That is, the collision warning is given in a manner that the driver perceives it through vision and hearing. The collision warning display element is a display element for notifying the driver of the collision risk. Specifically, a message prompting the driver to perform an avoidance operation (for example, a deceleration operation) is displayed as the collision warning display element. The collision warning sound is a sound (pip pip pip...) for notifying the driver of the collision risk. Since the driver performs an avoidance operation against the collision when recognizing the collision warning, the collision warning can be expressed as a warning for reducing the collision risk.

[0019] When the control condition that the TTC is less than or equal to the control threshold time Tve, which is smaller than the warning threshold time Tal, is satisfied, the ECU 20 performs vehicle control for reducing the collision risk. The control condition is a condition that is satisfied when the collision risk becomes greater than or equal to a control threshold value that is greater than the warning threshold value.

[0020] The ECU 20 performs at least one of automatic braking control and automatic steering control as vehicle control. The automatic braking control is control for automatically braking the vehicle VA. The automatic steering control is control for automatically steering the vehicle VA to move it to an avoidance space PS (see FIG. 2) on the side of an object.

[0021] (Outline of operation) The outline of the operation of the present device 10 will be described while referring to FIG. 2. When other warnings are being issued, the ECU 20 of the present device 10 relaxes the collision warning conditions more than when no other warnings are being issued. Specifically, when no other warnings are being issued, the ECU 20 sets the warning threshold time Tal to the first warning value Tal1, and when other warnings are being issued, the ECU 20 sets the warning threshold time Tal to "a second warning value Tal2 greater than the first warning value Tal1".

[0022] As shown in FIG. 2, when other warnings are being issued, the timing at which the collision warning is issued is earlier than when no other warnings are being issued (normal time). Even if the driver is delayed in recognizing the collision warning due to other warnings, the possibility that the collision risk has increased can be reduced.

[0023] Note that other warnings are, for example, an attention warning, a lane departure warning, a failure warning, a clearance sonar warning, etc. The attention warning is issued when the driver's attention has decreased. The lane departure warning is issued when the vehicle VA has deviated from the lane. The failure warning is issued when a failure has occurred in the vehicle VA. The clearance sonar warning is issued when the clearance sonar provided in the vehicle VA has detected an object. Other warnings are issued in a manner that the driver can recognize them through vision and hearing, similar to the collision warning.

[0024] Furthermore, when the "driver's driving operation situation (driving operation situation) and the driver's situation of gazing at an object (gazing situation)" after the collision warning started when other warnings are being issued satisfy a predetermined relaxation condition, the ECU 20 relaxes the control conditions more than when no other warnings are being issued.

[0025] More specifically, when a collision warning is issued, the ECU 20 determines whether the collision between the vehicle VA and the object can be avoided by the driver's driving operation, and also determines whether the driver is gazing at the object.

[0026] When vehicle control is activated even though a collision can be avoided through driver intervention, the driver is likely to find that vehicle control system annoying. Therefore, the ECU20 does not activate vehicle control when a collision can be avoided through driver intervention. This reduces the likelihood that the driver will find the vehicle control system annoying.

[0027] If a collision cannot be avoided by the driver's driving actions, and the driver is paying attention to the object, the driver is likely to take driving actions to avoid a collision with the object. In this case, the ECU20 determines the control condition using the "control threshold time Tve set in the first control value Tve1". That is, if the TTC becomes less than or equal to the first control value Tve1, the ECU20 determines that the control condition is met and executes vehicle control.

[0028] If a collision with an object cannot be avoided by the driver's driving actions, and the driver is not paying attention to the object, the driver may not yet be aware of the object posing a collision risk. Therefore, the driver may perform driving actions to avoid a collision with the object with a delay. In this case, the ECU20 determines that the mitigation condition has been met and determines the control condition using "a control threshold time Tve set to a second control value Tve2 that is greater than the first control value Tve1". The control condition in this case is more relaxed than the control condition under normal circumstances (when no other warnings are issued). Therefore, the ECU20 can perform vehicle control at an earlier timing than under normal circumstances, increasing the possibility of avoiding a collision with an object. Note that the second control value Tve2 is smaller than the first warning value Tal1.

[0029] (Specific operation) <Collision warning determination routine> The CPU of ECU20 executes the routine shown in the flowchart in Figure 3 at predetermined intervals. When the appropriate time arrives, the CPU starts processing from step 300 in Figure 3, and the processing proceeds to step 305.

[0030] In step 305, the CPU determines whether the collision warning flag Xal is "0". The collision warning flag Xal is set to "1" when a collision warning is issued and to "0" when a collision warning is not issued. Note that the collision warning flag Xal is set to "0" in the initialization routine. The initialization routine is executed by the CPU when the ignition key switch (not shown) of the vehicle VA is changed from the off position to the on position.

[0031] If the collision warning flag Xal is "0", the CPU determines "Yes" in step 305 and executes steps 310 and 315.

[0032] Step 310: The CPU recognizes an object in front of the vehicle VA based on image data and radar data. Step 315: The CPU determines whether or not other alarms have been triggered. If another ECU (not shown) is issuing another alarm by sending an instruction signal to a device that actually issues an alarm (e.g., a display device 48 and a speaker 50), the CPU may determine that the other alarm is activated when it receives the instruction signal sent by the other ECU. Furthermore, the device that actually issues the alarm may send a status notification signal to the CPU indicating the status of the alarm at predetermined intervals, and the CPU may determine whether or not the other alarm is being issued based on the status notification signal. In addition, the device 10 is equipped with a sound collection device (e.g., a microphone) installed in the vehicle cabin, and the CPU may determine whether or not the other alarm is being issued based on the sound data collected by the sound collection device.

[0033] If no other alarms are issued, the CPU determines "No" in step 315 and executes steps 320 through 330. Step 320: The CPU sets the alarm threshold time Tal to the first alarm value Tal1 and the control threshold time Tve to the first control value Tve1. Step 325: The CPU obtains the TTC of the object recognized in Step 310. Specifically, the CPU obtains the TTC by dividing the distance from the vehicle VA to the object by the relative velocity Vr of the object. Step 330: The CPU determines whether the minimum TTC is less than or equal to the alarm threshold time Tal.

[0034] If the minimum TTC is greater than the alarm threshold time Tal, the CPU determines "No" in step 330. Then, the process proceeds to step 395, and the CPU terminates this routine.

[0035] If the minimum TTC is less than or equal to the alarm threshold time Tal, the CPU determines "Yes" in step 330 and executes steps 335 and 340. An object that has a TTC less than or equal to the alarm threshold time Ta1 and is subject to collision warning is referred to as a "target object". Step 335: The CPU sets the collision warning flag Xal to "1" and the timer T to "0". Timer T is a timer used to count the time the driver is looking at the object after the collision warning. Step 340: The CPU issues a collision warning. If another warning is issued and can be temporarily suspended, the CPU will temporarily suspend that warning before issuing the collision warning. The process then proceeds to step 395, and the CPU terminates this routine.

[0036] On the other hand, if another alarm is triggered when the process proceeds to step 315, the CPU determines "Yes" in step 315, and the process proceeds to step 325. In step 325, the CPU sets the alarm threshold time Tal to the second alarm value Tal2 and the control threshold time Tve to the second control value Tve2. After that, the process proceeds to step 325.

[0037] As mentioned above, the second alarm value Tal2 is greater than the first alarm value Tal1. The collision alarm conditions are more likely to be met when other alarms are sounded than when other alarms are not sounded. Therefore, when other alarms are sounded, the collision alarm will start earlier than when other alarms are not sounded.

[0038] If the collision warning flag Xal is "1" when the process proceeds to step 305, the CPU determines "No" in step 305 and executes steps 350 and 355.

[0039] Step 350: The CPU obtains the acceleration input AP and the steering angle θ. Step 355: The CPU determines whether the termination condition has been met. Specifically, the CPU determines that the termination condition has been met if at least one of conditions E1 through E3 is met. Condition E1: Vehicle speed Vs is "0" (i.e., vehicle VA has stopped). Condition E2: An accelerator override has occurred. Specifically, if the subtraction value ΔAP (=AP-AP') obtained by subtracting the acceleration control amount AP' obtained in step 350 of this routine from the current acceleration control amount AP is greater than or equal to the threshold amount ΔAPth, the CPU determines that an accelerator override has occurred. Condition E3: The CPU determines that a steer override has occurred. Specifically, if the magnitude of the subtraction value Δθ (=θ-θ') obtained by subtracting the steering angle θ' obtained in step 350 of this routine from the current steering angle θ is greater than or equal to the threshold amount Δθth, the CPU determines that a steer override has occurred. The CPU may also determine that the termination condition has been met if any condition other than conditions E1 through E3 is met. For example, the CPU may determine that the termination condition has been met if the target object is no longer detected.

[0040] If none of conditions E1 through E3 are met, the termination condition is not met. In this case, the CPU determines "No" in step 355, and the process proceeds to step 340.

[0041] If at least one of conditions E1 through E3 is met, the termination condition is met. In this case, the CPU determines "Yes" in step 355, and the process proceeds to step 360. In step 360, the CPU sets the collision warning flag Xal, the automatic braking control flag Xbr, and the automatic steering control flag Xst to "0", and also sets the timer T to "0". After that, the process proceeds to step 395, and the CPU terminates this routine.

[0042] The automatic braking control flag Xbr is set to "1" when automatic braking control is performed, and to "0" when automatic braking control is not performed. The automatic braking control flag Xbr is set to "0" in the initialization routine.

[0043] The automatic steering control flag Xst is set to "1" when automatic steering control is performed, and to "0" when automatic steering control is not performed. The automatic steering control flag Xst is set to "0" in the initialization routine.

[0044] <Vehicle control determination routine> The CPU of ECU20 executes the routine shown in the flowchart in Figure 4 at predetermined intervals. When the appropriate time arrives, the CPU starts processing from step 400 in Figure 4, and the processing proceeds to step 405. In step 405, the CPU determines whether the collision warning flag Xal is "1".

[0045] If the collision warning flag Xal is "0", the CPU determines "No" in step 405. Then, the process proceeds to step 495, and the CPU terminates this routine.

[0046] If the collision warning flag Xal is "1", the CPU determines "Yes" in step 405 and executes steps 410 and 415.

[0047] Step 410: The CPU identifies the target object based on image data and radar data. Step 415: The CPU determines whether both the automatic braking control flag Xbr and the automatic steering control flag Xst are "0".

[0048] If both the automatic braking control flag Xbr and the automatic steering control flag Xst are "0", the CPU determines "Yes" in step 415 and executes steps 420 and 425.

[0049] Step 420: The CPU executes a collision avoidance determination subroutine to determine whether a collision with the target object can be avoided by the driver's driving actions. Step 425: The CPU determines in the collision avoidance determination subroutine whether or not a collision with the target object can be avoided by the driving operation.

[0050] If a collision with the target object can be avoided, the CPU determines "Yes" in step 425. The process then proceeds to step 495, and the CPU terminates this routine. As a result, if it is determined that a collision with the target object can be avoided by driving operations, neither automatic braking control nor automatic steering control is executed (i.e., vehicle control is not executed).

[0051] On the other hand, if a collision with the target object is unavoidable through driving operations, the CPU determines "No" in step 425 and executes steps 430 and 435.

[0052] Step 430: The CPU executes a gaze determination subroutine to determine whether the driver is looking at the target object. Step 435: The CPU determines whether the gaze determination subroutine has determined that the driver is looking at the target object.

[0053] If the driver is intently watching the target object, the CPU determines "Yes" in step 435 and executes steps 440 and 445.

[0054] Step 440: The CPU sets the control threshold time Tve to the first control value Tve1. If another warning is issued at the same time that the collision warning conditions are met, the control threshold time Tve is set to the second control value Tve2 in step 345 shown in Figure 3, and therefore, in step 440 shown in Figure 4, the control threshold time Tve is returned to the first control value Tve1. If the driver is intently watching the target object, there is a high probability that the driver will perform appropriate evasive maneuvers, so there is no need to advance the timing of vehicle control execution. Step 445: The CPU determines whether the target object's TTC is less than or equal to the control threshold time Tve.

[0055] If TTC is greater than the control threshold time Tve, the CPU determines "No" in step 445. Then, the process proceeds to step 495, and the CPU terminates this routine.

[0056] If the TTC is less than or equal to the control threshold time Tve, the CPU determines "Yes" in step 445, and the process proceeds to step 450. In step 450, the CPU determines whether the vehicle VA can move to the avoidance space PS.

[0057] First, the CPU determines whether there is a avoidance space PS to the side of the target object that is larger than the size of the vehicle VA's body. If an avoidance space PS exists, the CPU obtains the lateral movement De of the vehicle VA if it were traveling at the current speed Vs and a predetermined steering angle θpd during the period from the current moment until the target object's TTC has elapsed. The CPU then obtains the required lateral movement Dn, which represents the lateral distance between the vehicle VA and the avoidance space PS at the current moment. The CPU determines that the vehicle VA can move to the avoidance space PS if the lateral movement De is greater than the required lateral movement Dn, and that the vehicle VA cannot move to the avoidance space PS if the lateral movement De is less than or equal to the required lateral movement Dn.

[0058] If vehicle VA cannot move to the avoidance space PS, the CPU determines "No" in step 450 and executes steps 455 and 460. Step 455: The CPU sets the automatic braking control flag Xbr to "1" and the automatic steering control flag Xst to "0". In this embodiment, both the automatic braking control flag Xbr and the automatic steering control flag Xst are never set to "1". When vehicle control is performed, either the automatic braking control flag Xbr or the automatic steering control flag Xst is set to "1". Step 460: The CPU performs automatic braking control. Specifically, the CPU controls the powertrain actuator 40 and the brake actuator 42 so that the acceleration G of the vehicle VA matches a predetermined target deceleration Gbr. The process then proceeds to step 495, and the CPU terminates this routine.

[0059] On the other hand, if vehicle VA can move to avoidance space PS, the CPU determines "Yes" in step 450 and executes steps 465 and 470. Step 465: The CPU sets the automatic braking control flag Xbr to "0" and the automatic steering control flag Xst to "1". Step 470: The CPU performs automatic steering control. Specifically, the CPU controls the steering motor 44 so that the steering angle θ matches the "target steering angle θtgt for the vehicle VA to travel along the path to move to the avoidance space PS". The process then proceeds to step 495, and the CPU terminates this routine.

[0060] If at least one of the automatic braking control flag Xbr and the automatic steering control flag Xst is "1" when the process proceeds to step 415, the CPU determines "No" in step 415 and the process proceeds to step 475. In step 475, the CPU determines whether or not the automatic braking control flag Xbr is "1".

[0061] If the automatic braking control flag Xbr is "1", the CPU determines "Yes" in step 475, and the process proceeds to step 460.

[0062] On the other hand, if the automatic braking control flag Xbr is "0", then the automatic steering control flag Xst is "1". In this case, the CPU determines "No" in step 475, and the process proceeds to step 470.

[0063] If the driver is not looking at the target object when the process proceeds to step 435 (i.e., the mitigation condition is met), the CPU determines "No" in step 435, and the process proceeds to step 445. As a result, if other warnings are issued, the control threshold time Tve is set to the second control value Tve2 in step 345 as shown in Figure 3, so the timing of vehicle control execution is advanced.

[0064] <Collision Avoidance Detection Subroutine> If the process proceeds to step 420, the CPU starts processing from step 500 as shown in Figure 5, and the process proceeds to step 505. In step 505, the CPU determines whether or not there is an avoidance space PS to the side of the target object.

[0065] If an avoidance space PS exists, the CPU determines "Yes" in step 505 and executes steps 510 and 515.

[0066] Step 510: The CPU obtains the measurement value from the steering angle sensor 34 and determines the steering angle θ. Step 515: The CPU determines the steering direction of the steering wheel based on the steering angle θ and determines whether the steering direction is in the direction of the avoidance space PS.

[0067] If the steering direction is in the direction of the avoidance space PS, the CPU determines "Yes" in step 515 and executes steps 520 to 530.

[0068] Step 520: The CPU estimates the lateral displacement De, which represents the amount of lateral movement of vehicle VA when it travels at the current "vehicle speed Vs and steering angle θ" during the period from the current time until the time to the object's TTC has elapsed. Step 525: The CPU obtains the required lateral movement amount Dn, which represents the lateral distance between the vehicle VA and the avoidance space PS at the current time. Step 530: The CPU determines whether the lateral movement amount De is greater than the required lateral movement amount Dn.

[0069] If the lateral movement amount De is greater than the required lateral movement amount Dn, the CPU determines "Yes" in step 530, and the process proceeds to step 535. In step 535, the CPU determines that a collision with the target object can be avoided by driving operations. The process then proceeds to step 595, and the CPU terminates this routine. The process then proceeds to step 425, as shown in Figure 4.

[0070] If there is no avoidance space PS to the side of the target object (step 505 "No" shown in Figure 5), if the steering direction is not in the direction of the avoidance space PS (step 515 "No"), and if the lateral movement amount De is less than or equal to the required lateral movement amount Dn (step 530 "No"), the CPU executes steps 540 to 550.

[0071] Step 540: The CPU obtains the measurement value from the deceleration amount sensor 32 and determines the deceleration amount BP. Step 545: The CPU obtains the required deceleration Gn so that the relative velocity Vr of the target object becomes "0" when the time to traffic (TTC) of the target object has elapsed from the current point in time, assuming that the target object continues to move at its current velocity. Note that the required deceleration Gn is the deceleration that would allow a collision with the target object to be avoided. Step 550: The CPU determines whether the deceleration Gd corresponding to the deceleration operation amount BP is greater than the required deceleration Gn.

[0072] If the deceleration Gd is greater than the required deceleration Gn, the CPU determines "Yes" in step 550, and the process proceeds to step 535. In this case, the CPU determines that a collision with the target object can be avoided by driving maneuvers.

[0073] On the other hand, if the deceleration Gd is less than or equal to the required deceleration Gn, the CPU determines "No" in step 550, and the process proceeds to step 555. In step 555, the CPU determines that a collision with the target object is unavoidable through driving operations. The process then proceeds to step 595, where the CPU terminates this routine. The process then proceeds to step 425, as shown in Figure 4.

[0074] <Looking detection subroutine> If the process proceeds to step 430, the CPU starts processing from step 600 as shown in Figure 6 and executes steps 605 and 610.

[0075] Step 605: The CPU acquires driver image data from the driver camera 26. Step 610: The CPU obtains the gaze direction, which represents the direction of the driver's gaze, based on the driver image data, and determines whether the gaze direction matches the direction of the target object. Specifically, if the angular difference between the gaze direction and the direction of the target object is less than or equal to a threshold, the CPU determines that the gaze direction matches the direction of the target object.

[0076] If the line of sight matches the direction of the target object, the CPU determines "Yes" in step 610 and executes steps 615 and 620. Step 615: The CPU adds "1" to Timer T. Step 620: The CPU determines whether timer T is greater than or equal to the threshold Tth.

[0077] If timer T is greater than or equal to threshold Tth, the CPU determines "Yes" in step 620, and the process proceeds to step 625. In step 625, the CPU determines that the driver is looking at the target object. The process then proceeds to step 695, where the CPU terminates this routine. The process then proceeds to step 435, as shown in Figure 4.

[0078] If the line of sight does not match the direction of the target object (step 610 "No"), and if timer T is less than the threshold Tth (step 620 "No"), the process proceeds to step 630. In step 630, the CPU determines that the driver is not looking at the target object. The process then proceeds to step 695, where the CPU terminates this routine. The process then proceeds to step 435 as shown in Figure 4.

[0079] As explained above, the device 10 relaxes the collision warning conditions when other warnings are issued compared to when other warnings are not issued. This allows the device 10 to reduce the likelihood of an increased collision risk even if the driver is late in recognizing the collision warning.

[0080] In the above embodiment, the CPU used TTC as an index value for collision risk, but other values ​​may be used. For example, the CPU may use "distance between the object and the vehicle VA" as the index value. This index value means that the shorter the distance, the higher the collision risk.

[0081] In the above embodiment, the CPU relaxed the collision warning conditions and control conditions by increasing the threshold time, but the collision warning conditions and control conditions may also be relaxed by making the TTC smaller than the actual value (i.e., by making the collision risk index value represent a collision risk higher than the actual value).

[0082] The first alarm value Tal1, the second alarm value Tal2, the first control value Tve1, and the second control value Tve2 may be set to larger values ​​as the relative velocity Vr of the object increases.

[0083] In the above embodiment, the CPU does not automatically decelerate the vehicle VA in automatic steering control, but it may automatically decelerate the vehicle VA in automatic steering control. The CPU only needs to perform at least one of automatic braking control and automatic steering control as vehicle control.

[0084] Collision warnings and other warnings should be provided in a manner that allows the driver to perceive them through at least one of their visual and auditory senses.

[0085] This device 10 is applicable to vehicles such as engine-powered vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, and electric vehicles. Furthermore, this device 10 is also applicable to vehicles that perform autonomous driving to assist the driver. [Explanation of symbols]

[0086] 10...Vehicle control device, 26...Driver's seat camera, 40...Powertrain actuator, 42...Brake actuator, 44...Steering motor, 48...Display device, 50...Speaker.

Claims

1. In a vehicle control device configured to issue a collision warning to reduce the collision risk when the collision warning condition is met, such that the risk of a vehicle colliding with an object is greater than or equal to a warning threshold, The vehicle control device is configured to relax the collision warning conditions when another warning different from the collision warning is issued, compared to when the other warning is not issued. Vehicle control device.

2. In the vehicle control device according to claim 1, The aforementioned vehicle control device is When the control condition is met that the collision risk is greater than or equal to a control threshold greater than the warning threshold, the vehicle control is executed, which includes at least one of the following: automatic braking control that automatically brakes the vehicle to reduce the collision risk, and automatic steering control that automatically steers the vehicle to reduce the collision risk. When the collision warning conditions are met and the other warnings are issued, if the driving operation status, which represents the state of the driver's driving operations of the vehicle after the collision warning, and the attention status, which represents the state of the driver's attention to the object after the collision warning, satisfy the predetermined relaxation conditions, the control conditions are relaxed compared to when the other warnings are not issued. A vehicle control device configured as follows.

3. In the vehicle control device according to claim 2, The vehicle control device is configured such that, when the collision warning condition is met and another warning is issued, the mitigation condition is met when the collision between the vehicle and the object cannot be avoided by the driving operation and the driver is not paying attention to the object, thereby mitigating the control condition compared to when no other warning is issued. Vehicle control device.

4. In the vehicle control device according to claim 2, The aforementioned vehicle control device is When the collision warning conditions are met and the other warnings are being issued, When the collision is avoided by the aforementioned driving operation, the vehicle control is not performed. If the collision is not avoided by the aforementioned driving operation and the driver is keeping their eyes on the object, the control conditions are not relaxed. A vehicle control device configured as follows.

5. In the vehicle control device according to claim 2, The aforementioned vehicle control device is The vehicle is equipped with a driver camera that acquires image data of the driver's face, If there is a clearance space to the side of the object, and the amount of lateral movement of the vehicle before it collides with the object is greater than the lateral distance between the vehicle and the clearance space, or if the deceleration corresponding to the driver's current deceleration control operation is greater than the deceleration required to avoid the collision, then it is determined that the collision can be avoided by the driving operation. If, based on the image data, the driver's gaze is directed toward the object for a predetermined period of time or longer, it is determined that the driver is intently watching the object. A vehicle control device configured as follows.

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