Vehicle control device

Abstract

The present invention relates to a vehicle control device. The vehicle control device is configured to execute collision avoidance control for avoiding a collision with an object. The collision avoidance control at least includes: steering control that varies the steering angle of the steering wheel of the vehicle along a target path (TP); and braking force control that applies a braking force to the wheels of the vehicle in accordance with a target deceleration (TG). When a prescribed steering end condition is satisfied, the vehicle control device ends the braking force control by reducing the magnitude of the target deceleration at a first gradient. When a prescribed cancellation condition is satisfied, the vehicle control device ends the braking force control by reducing the magnitude of the target deceleration at a second gradient. The second gradient is larger than the first gradient.

Description

Technical Field

[0001] The present disclosure relates to a vehicle control device configured to perform collision avoidance control. Background Art

[0002] Conventionally, a vehicle control device has been proposed that is configured to perform collision avoidance control for avoiding a collision between a vehicle and an obstacle (for example, Patent Document 1). For example, the collision avoidance control includes steering control that changes the steering angle of the steering wheel of the vehicle and braking force control that applies a braking force to the wheels.

[0003] When the vehicle control device determines that the vehicle may collide with an obstacle, it performs steering control and braking force control. As a result, the vehicle passes by the side of the obstacle while decelerating.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-043262

[0007] For example, it is assumed that when the collision with the obstacle is avoided, the vehicle control device ends the steering control and the braking force control simultaneously. In this case, the deceleration of the vehicle immediately ends, so the driver may feel discomfort.

[0008] In another example, it is assumed that the driver performs a driving operation (for example, an operation of the accelerator pedal) during the execution of the steering control and the braking force control. In this case, the acceleration of the vehicle is suppressed by the braking force control. Since the driver's driving operation is not reflected in the vehicle, the driver may feel discomfort. Summary of the Invention

[0009] The present disclosure provides a technique that can change the end process of the braking force control according to the situation, thereby reducing the possibility that the driver feels discomfort.

[0010] The vehicle control device in one or more embodiments includes:

[0011] a sensor (17) configured to acquire object information, which is information related to an object present in a peripheral area of the vehicle including at least the front area of the vehicle; and

[0012] a control unit (10) configured to determine whether a prescribed execution condition that is established when the possibility of collision between the vehicle and the object is high is established based on the object information, and perform collision avoidance control for avoiding a collision with the object when it is determined that the prescribed execution condition is established.

[0013] The collision avoidance control at least includes:

[0014] Steering control to vary the steering angle of the steering wheel of the vehicle along a target path that is a path for avoiding a collision with the object; and

[0015] Braking force control to apply a braking force to the wheels of the vehicle in accordance with a target deceleration (TG).

[0016] The control unit is configured to:

[0017] When a prescribed steering end condition is satisfied, end the steering control and end the braking force control by reducing the magnitude of the target deceleration at a first inclination, where the prescribed steering end condition is a condition that is satisfied when the avoidance of a collision with the object is completed by the steering control

[0018] When a prescribed cancellation condition is satisfied, end the steering control and end the braking force control by reducing the magnitude of the target deceleration at a second inclination, where the prescribed cancellation condition is a condition that is satisfied when the driver of the vehicle performs a driving operation,

[0019] The second inclination is larger than the first inclination.

[0020] According to the above configuration, the vehicle control device can vary the ending process of the braking force control according to the situation. When the steering end condition is satisfied, the vehicle control device ends the braking force control by reducing the magnitude of the target deceleration at a first inclination. According to this configuration, when the steering end condition is satisfied, the magnitude of the target deceleration does not suddenly become zero but gradually decreases. Therefore, the possibility of the driver feeling discomfort can be reduced.

[0021] On the other hand, when the cancellation condition is satisfied, the vehicle control device ends the braking force control by reducing the magnitude of the target deceleration at a second inclination. The second inclination is larger than the first inclination. When the driver performs a driving operation, the magnitude of the target deceleration becomes zero faster than when the steering end condition is satisfied. Since the driver's driving operation is reflected in the vehicle, the possibility of the driver feeling discomfort can be reduced.

[0022] In one or more embodiments, the control unit is configured to: also when the cancellation condition is satisfied after the steering end condition is satisfied, end the braking force control by reducing the magnitude of the target deceleration at the second inclination.

[0023] According to the above configuration, when the driver performs a driving operation after the steering control ends, the braking force control ends quickly. Since the driver's driving operation is reflected in the vehicle, the possibility that the driver feels discomfort can be reduced.

[0024] In one or more embodiments, the control unit is configured to: when the vehicle passes by the side of the object and the magnitude of the steering angle is below a specified steering angle value (θn) and this state continues for a duration threshold (Tdth) or more, determine that the steering end condition is satisfied.

[0025] In one or more embodiments, the control unit is configured to: when at least one of a first condition and a second condition is satisfied, determine that the cancellation condition is satisfied, where the first condition is that the operation amount (AP) of the accelerator pedal is equal to or greater than a specified operation amount threshold (APth), and the second condition is that the magnitude of the steering torque (Tra) acting on the steering shaft by operating the steering wheel (SW) is equal to or greater than a specified torque threshold (Trth).

[0026] In one or more embodiments, it may be that the above control unit is implemented by a microprocessor programmed to execute one or more functions described in this specification. In one or more embodiments, it may be that the above control unit is implemented in whole or in part by hardware composed of one or more application specific integrated circuits (ASICs) and the like.

[0027] In the above description, for the components corresponding to one or more of the embodiments described later, the names and / or reference numerals used in the embodiments are added in parentheses. However, each component is not limited to the embodiments defined by the said names and / or reference numerals. From the description of one or more embodiments described with reference to the following drawings, other objects, other features, and accompanying advantages of the present disclosure will be easily understood. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic configuration diagram of a vehicle control device according to one or more embodiments.

[0029] Figure 2 is a diagram for explaining object information acquired by a surrounding sensor.

[0030] Figure 3 is a top view for explaining a target path (avoidance path).

[0031] Figure 4 is a state transition diagram of control states.

[0032] Figure 5 It is a top view showing the state of the vehicle when driving on the road where the object (n) exists.

[0033] Figure 6 It is a graph showing "the changes of the vehicle speed Vs and the target deceleration TG with respect to time t" in Working Example 1.

[0034] Figure 7 It is a graph showing "the changes of the vehicle speed Vs and the target deceleration TG with respect to time t" in Working Example 2.

[0035] Figure 8 It is a graph showing "the changes of the vehicle speed Vs and the target deceleration TG with respect to time t" in Working Example 3.

[0036] Figure 9 It is a flowchart showing the first routine executed by the collision avoidance ECU.

[0037] Figure 10 It is a flowchart showing the second routine executed by the collision avoidance ECU.

[0038] Figure 11 It is a flowchart showing the third routine executed by the collision avoidance ECU.

[0039] Explanation of reference numerals

[0040] 10... Collision avoidance ECU, 20... Engine ECU, 30... Brake ECU, 40... Steering ECU, 50... Instrument ECU. Detailed implementation manners

[0041] (Configuration of the vehicle control device)

[0042] As Figure 1 shown, the vehicle control devices of one or more embodiments are applied to the vehicle VA. The vehicle control device includes a collision avoidance ECU 10, an engine ECU 20, a brake ECU 30, a steering ECU 40, and an instrument ECU 50. Several or all of these ECUs may also be integrated into one ECU.

[0043] The above-mentioned ECUs 10 to 50 are electric control devices (Electric Control Unit: electronic control unit) having a microcomputer as the main part, and are connected in such a way that they can send information to and receive information from each other via a CAN (Controller Area Network) not shown.

[0044] In this specification, a microcomputer includes a CPU (Central Processing Unit), a ROM (Read-Only Memory), a RAM (Random Access Memory), a non-volatile memory, an interface I / F, etc. For example, the collision avoidance ECU 10 includes a microcomputer, which includes a CPU 101, a ROM 102, a RAM 103, a non-volatile memory 104, an interface (I / F) 105, etc. The CPU 101 realizes various functions by executing instructions (programs, routines) stored in the ROM 102.

[0045] The collision avoidance ECU 10 is connected to the sensors listed below and receives their detection signals or output signals. It should be noted that each sensor can also be connected to an ECU other than the collision avoidance ECU 10. In this case, the collision avoidance ECU 10 receives the detection signal or output signal of the sensor from the ECU to which the sensor is connected via the CAN.

[0046] The accelerator pedal operation amount sensor 11 detects the operation amount AP of the accelerator pedal 11a and outputs a signal representing the accelerator pedal operation amount AP. The brake pedal operation amount sensor 12 detects the operation amount BP of the brake pedal 12a and outputs a signal representing the brake pedal operation amount BP.

[0047] The vehicle speed sensor 13 detects the speed (traveling speed) Vs of the vehicle VA and outputs a signal representing the speed Vs. The yaw rate sensor 14 detects the yaw rate Yr of the vehicle VA and outputs a signal representing the yaw rate Yr.

[0048] The steering torque sensor 15 detects the steering torque Tra acting on the steering shaft US through the driver's operation of the steering wheel SW (steering operation) and outputs a signal representing the steering torque Tra. It should be noted that the value of the steering torque Tra is positive when the steering wheel SW is rotated in the first direction (left direction), and negative when the steering wheel SW is rotated in the second direction (right direction).

[0049] The steering angle sensor 16 detects the steering angle θ of the vehicle VA and outputs a signal representing the steering angle θ. The value of the steering angle θ is positive when the steering wheel SW is rotated from the specified reference position (neutral position) in the first direction (left direction), and negative when the steering wheel SW is rotated from the specified reference position in the second direction (right direction). It should be noted that the reference position is the position where the steering angle θ is zero, which is the position of the steering wheel SW when the vehicle VA is traveling straight.

[0050] After that, the "information indicating the driving state of the vehicle VA" output from the sensors 11 to 16 is sometimes referred to as "driving state information".

[0051] The surrounding sensor 17 acquires information related to the road around the vehicle VA (including the driving lane on which the vehicle VA is traveling) and information related to the three-dimensional objects existing on the road. The three-dimensional objects include, for example, moving objects such as pedestrians, four-wheeled vehicles, and two-wheeled vehicles, and stationary objects such as guardrails and fences. Hereinafter, these three-dimensional objects are referred to as "objects".

[0052] As Figure 2 shown, the surrounding sensor 17 acquires object information in a two-dimensional coordinate system. The two-dimensional coordinate system is defined by the x-axis and the y-axis. The origin of the x-axis and the origin of the y-axis are the central position O in the vehicle width direction at the front of the vehicle VA. The x-axis extends in a manner that passes through the central position O of the vehicle VA along the front-rear direction of the vehicle VA and has the front as the positive value axis. The y-axis is orthogonal to the x-axis and has the left direction of the vehicle VA as the positive value axis.

[0053] The object information includes the longitudinal distance Dfx(n) of the object (n), the lateral position Dfy(n) of the object (n), the azimuth θp of the object (n) with respect to the vehicle VA, the traveling direction of the object (n), the relative speed Vfx(n) of the object (n), and the category of the object (n), etc.

[0054] The longitudinal distance Dfx(n) is the signed distance between the object (n) in the x-axis direction and the origin O. The lateral position Dfy(n) is the signed distance between the object (n) in the y-axis direction and the origin O. The relative speed Vfx(n) is the difference between the speed Vn of the object (n) and the speed Vs of the vehicle VA (=Vn - Vs). The speed Vn of the object (n) is the speed of the object (n) in the x-axis direction. The category of the object (n) is information indicating which of the moving object and the stationary object the object corresponds to.

[0055] Referring again to Figure 1 , the surrounding sensor 17 includes a radar sensor 18 and a camera sensor 19.

[0056] The radar sensor 18 radiates radio waves in the millimeter wave band (hereinafter referred to as "millimeter waves") to a peripheral area including at least the front area of the vehicle VA, and receives the millimeter waves (i.e., reflected waves) reflected by the objects existing in the radiation range. And, the radar sensor 18 detects the object (n) based on the reflected wave information including the phase difference between the transmitted millimeter waves and the received reflected waves, the attenuation level of the reflected waves, and the time from transmitting the millimeter waves to receiving the reflected waves. Moreover, the radar sensor 18 acquires (calculates) the object information about the object (n) based on the reflected wave information.

[0057] The camera sensor 19 captures the scenery in front of the vehicle VA to obtain image data. The camera sensor 19 identifies the left dividing line LL and the right dividing line RL that define the driving lane based on the image data. And, as Figure 2 shown, the camera sensor 19 obtains the position information of the left dividing line LL and the right dividing line RL in a two-dimensional coordinate system. The information obtained by the camera sensor 19 is referred to as "lane information". It should be noted that the camera sensor 19 can also be configured to determine the presence or absence of an object based on the image data and calculate the object information.

[0058] The surrounding sensor 17 outputs the information related to the surrounding conditions of the vehicle VA, including "object information and lane information", as "vehicle surrounding information" to the collision avoidance ECU 10.

[0059] As Figure 2 shown, the collision avoidance ECU 10 uses the vehicle surrounding information to identify the shape of the driving lane Ln1 defined by the left dividing line LL and the right dividing line RL, the positions of the vehicle VA and the object (n) in the driving lane Ln1, and the orientation of the vehicle VA relative to the driving lane Ln1, etc.

[0060] Refer again to Figure 1 , the engine ECU 20 is connected to the engine actuator 21. The engine actuator 21 includes a throttle actuator that changes the opening degree of the throttle of the spark ignition gasoline fuel injection internal combustion engine 22. The engine ECU 20 can change the torque generated by the internal combustion engine 22 by driving the engine actuator 21. The torque generated by the internal combustion engine 22 is transmitted to the drive wheels (not shown) via a transmission (not shown). Therefore, the engine ECU 20 can control the driving force to change the acceleration state (acceleration) of the vehicle VA by controlling the engine actuator 21.

[0061] It should be noted that in the case where the vehicle VA is a hybrid vehicle, the engine ECU 20 can control the driving force generated by either one or both of the "internal combustion engine and electric motor" that are the vehicle drive sources. Moreover, in the case where the vehicle VA is an electric vehicle, the engine ECU 20 can control the driving force generated by the electric motor that is the vehicle drive source.

[0062] The brake ECU 30 is connected to the brake actuator 31. The brake actuator 31 includes a hydraulic circuit. The hydraulic circuit includes a master cylinder, a flow path for the brake fluid to flow, a plurality of valves, a pump, and a motor for driving the pump, etc. The brake ECU 30 adjusts the hydraulic pressure supplied to the wheel cylinder built in the braking mechanism 32 by controlling the brake actuator 31. The wheel cylinder uses this hydraulic pressure to generate frictional braking force on the wheels. Therefore, the brake ECU 30 can control the braking force by controlling the brake actuator 31 to change the acceleration state (deceleration, i.e., negative acceleration) of the vehicle VA.

[0063] The steering ECU 40 is a control device of a well-known electric power steering system and is connected to the assist motor 41. The assist motor 41 is assembled in the steering mechanism of the vehicle VA (including the steering wheel SW, the steering shaft US, and the steering gear mechanism, etc.). The assist motor 41 can generate torque and use this torque to apply a steering assist torque or steer the left and right steering wheels.

[0064] The meter ECU 50 is connected to the display 51 and the speaker 52. The display 51 is a multi-information display provided in the front of the driver's seat. The speaker 52 generates a sound corresponding to the sound generation command from the collision avoidance ECU 10 when receiving the sound generation command.

[0065] (Collision avoidance control)

[0066] After that, the collision avoidance ECU 10 will be only referred to as "ECU 10". The ECU 10 is configured to execute collision avoidance control. The collision avoidance control is a control for avoiding a collision with an obstacle existing in the front area of the vehicle VA. Such collision avoidance control is well-known (for example, refer to Japanese Unexamined Patent Application Publication No. 2017-043262 and Japanese Unexamined Patent Application Publication No. 2018-103645, etc.). Hereinafter, the processing flow of the collision avoidance control will be described.

[0067] The ECU 10 detects an object (n) existing in the peripheral area of the vehicle VA based on the object information included in the vehicle surrounding information.

[0068] The ECU 10 calculates a first predicted trajectory based on the driving state information (for example, speed Vs, yaw rate Yr, and steering angle θ, etc.). The first predicted trajectory is a trajectory predicted that the vehicle VA will pass through.

[0069] The ECU 10 determines whether the object (n) is a moving object or a stationary object based on the object information. In the case where the object is a moving object, the ECU 10 calculates a second predicted trajectory based on the object information (for example, the traveling direction of the object (n)). The second predicted trajectory is a trajectory predicted that the object (n) will pass through.

[0070] When the object (n) is a stationary object, the ECU 10 determines whether there is a possibility of a collision between the vehicle VA and the object (n) based on the first predicted trajectory and the position of the object (n). When the first predicted trajectory interferes with the position of the object (n), the ECU 10 determines that there is a possibility of a collision between the vehicle VA and the object (n).

[0071] On the other hand, when the object (n) is a moving object, the ECU 10 determines whether there is a possibility of a collision between the vehicle VA and the object (n) based on the first predicted trajectory and the second predicted trajectory. When the first predicted trajectory intersects the second predicted trajectory, the ECU 10 determines that there is a possibility of a collision between the vehicle VA and the object (n).

[0072] When the ECU 10 determines that there is a possibility of a collision between the vehicle VA and the object (n), the ECU 10 determines (sets) the object (n) as an obstacle.

[0073] Next, the ECU 10 determines whether a specified execution condition is satisfied. The execution condition is a condition for determining whether to execute (start) collision avoidance control. Specifically, the ECU 10 calculates the time to collision (TTC) required for the vehicle VA to collide with the obstacle based on the longitudinal distance Dfx(n) from the obstacle and the relative speed Vfx(n). Hereinafter, the time to collision TTC will be simply referred to as "TTC". The TTC is calculated by dividing the distance Dfx(n) by the relative speed Vfx(n).

[0074] The execution condition is satisfied when the TTC is equal to or less than a specified time threshold Tath. When the TTC is equal to or less than the time threshold Tath, this means that the possibility of a collision between the vehicle VA and the obstacle is high. Therefore, the ECU 10 executes collision avoidance control for the obstacle.

[0075] In this example, the collision avoidance control includes at least braking control and steering control. The steering control is a control that changes the steering angle of the steering wheel of the vehicle VA along a target path (avoidance path) TP for avoiding a collision with the obstacle. The braking control is a control that applies a braking force to the wheels of the vehicle VA according to a target deceleration TG. Hereinafter, the braking control and the steering control will be described separately.

[0076] · Steering control

[0077] As Figure 3As shown, the ECU 10 calculates the target path TP. The target path TP is the path that the center position O of the vehicle VA (the center position in the vehicle width direction at the front of the vehicle VA) will pass through. The target path TP is set such that the distance ds in the road width direction between the vehicle VA and the object (n) is equal to or greater than a specified distance threshold dth and the vehicle VA does not deviate from the driving lane Ln1. Moreover, the target path TP is set such that the traveling direction of the vehicle VA finally coincides with the direction dr1 in which the driving lane Ln1 extends. According to this configuration, the traveling direction of the vehicle VA finally becomes parallel to the left dividing line LL and the right dividing line RL. Even if the driver does not turn the steering wheel SW, the vehicle VA will not deviate from the driving lane Ln1.

[0078] The ECU 10 calculates the target steering torque Atr based on the target path TP. The target steering torque Atr is a control quantity for causing the vehicle VA to travel along the target path TP and is sometimes referred to as the "steering control quantity". The ECU 10 sends a steering instruction signal (including the target steering torque Atr) to the steering ECU 40. When the steering ECU 40 receives the steering instruction signal from the ECU 10, it drives the assist motor 41 based on the target steering torque Atr.

[0079] After starting the steering control, the ECU 10 determines whether a specified steering end condition is satisfied. The steering end condition is a condition that is satisfied when the avoidance of a collision with an obstacle (object (n)) is completed by the steering control.

[0080] Specifically, the steering end condition is satisfied when the vehicle VA passes by the side of the object (n) and the magnitude (absolute value) of the steering angle θ of the vehicle VA is equal to or less than a specified steering angle value θn (for example, a value close to zero) for a duration equal to or greater than a specified duration threshold Tdth. This means that the vehicle VA passes by the side of the object (n) and the traveling direction of the vehicle VA is parallel to the left dividing line LL and the right dividing line RL. Therefore, the vehicle VA will not collide with the object (n), and the vehicle VA will not deviate from the driving lane Ln1. Therefore, when the steering end condition is satisfied, the ECU 10 ends the steering control. Moreover, as described below, after ending the steering control, the ECU 10 ends the braking force control. In this way, the ECU 10 ends the steering control and the braking force control at different timings.

[0081] Moreover, after starting the collision avoidance control, the ECU 10 determines whether a specified cancellation condition is satisfied. The cancellation condition is a condition for canceling (terminating) the collision avoidance control and is a condition that is satisfied when the driver performs a specified driving operation.

[0082] Specifically, the cancellation condition is satisfied when at least one of the following condition A1 and condition A2 is satisfied.

[0083] (Condition A1) The accelerator pedal operation amount AP is equal to or greater than a specified operation amount threshold APth.

[0084] (Condition A2) The magnitude (absolute value) of the steering torque Tra is equal to or greater than a specified torque threshold Trth.

[0085] It should be noted that the timing when the cancellation condition is satisfied is as follows (a) or (b).

[0086] (a) Before the steering end condition is satisfied, the cancellation condition is satisfied. This means that before the vehicle VA passes by the side of the object (n), the driver performs a driving operation (operation of the accelerator pedal 11a and / or operation of the steering wheel SW) for avoiding a collision with the object (n).

[0087] (b) After the steering end condition is satisfied, the cancellation condition is satisfied. This means that after the vehicle VA passes by the side of the object (n), the driver resumes the driving operation (operation of the accelerator pedal 11a and / or operation of the steering wheel SW).

[0088] In the situation of (a), the ECU10 ends the steering control, and then ends the braking force control.

[0089] In the situation of (b), the steering control has already ended. Therefore, the ECU10 ends the braking force control.

[0090] · Braking force control

[0091] The ECU10 sets the target deceleration TG. The ECU10 sends a braking instruction signal including the target deceleration TG to the brake ECU30. When receiving the braking instruction signal from the ECU10, the brake ECU30 controls the brake actuator 31, thereby applying a braking force to the wheels so that the actual acceleration of the vehicle VA coincides with the target deceleration TG.

[0092] In this example, the braking force control includes a first deceleration control, a second deceleration control, and a third deceleration control. The ECU10 executes any one of the first deceleration control, the second deceleration control, and the third deceleration control according to Figure 4 the state transition of the control state shown.

[0093] As Figure 4 shown, the control state includes a first state 401, a second state 402, and a third state 403. After starting the braking force control, the ECU10 repeatedly determines which one of the first state 401, the second state 402, and the third state 403 the control state is.

[0094] As Figure 4As shown, when the execution condition is satisfied (i.e., when the braking force control starts), first, the ECU 10 determines that the control state is the first state 401. The first state 401 is a state in which neither the steering end condition nor the cancellation condition is satisfied. In the situation where the control state is the first state 401, the ECU 10 executes the first deceleration control. The first deceleration control is a control for decelerating the vehicle VA by setting the target deceleration TG to the deceleration da1 (negative acceleration).

[0095] When the steering end condition is satisfied in the situation where the control state is the first state 401, the ECU 10 changes the control state from the first state 401 to the second state 402. In the second state 402, the avoidance of a collision with an obstacle has been completed, and the driver has not yet restarted the driving operation (operation of the accelerator pedal 11a and / or operation of the steering wheel SW). If the deceleration of the vehicle VA is immediately ended in this state, the driver may feel discomfort. Therefore, in the situation where the control state is the second state 402, the ECU 10 executes the second deceleration control. The second deceleration control is a control for decelerating the vehicle VA while reducing the magnitude (absolute value) of the target deceleration TG at a first inclination. More specifically, the change amount per unit time dT of the magnitude of the target deceleration TG in the second deceleration control is the first change amount ΔG1 (>0). According to this configuration, since the magnitude of the target deceleration TG gradually decreases, the possibility that the driver feels discomfort can be reduced. Moreover, sufficient time delay can be given to the driver to restart the driving operation.

[0096] When the cancellation condition is satisfied in the situation where the control state is the first state 401 or the second state 402, the ECU 10 changes the control state to the third state 403. In the third state 403, the driver performs a driving operation (operation of the accelerator pedal 11a and / or operation of the steering wheel SW). If the acceleration of the vehicle VA is suppressed due to the braking force control, the driver may feel discomfort. Therefore, in the situation where the control state is the third state 403, the ECU 10 executes the third deceleration control. The third deceleration control is a control for decelerating the vehicle VA while reducing the magnitude (absolute value) of the target deceleration TG at a second inclination. The second inclination is larger than the first inclination. More specifically, the change amount per unit time dT of the magnitude of the target deceleration TG in the third deceleration control is the second change amount ΔG2 (>0). The second change amount ΔG2 is larger than the first change amount ΔG1.

[0097] It should be noted that after starting the braking force control, the ECU 10 determines whether a specified braking end condition is satisfied. The braking end condition is satisfied when one of the following condition B1 and condition B2 is satisfied. When the braking end condition is satisfied, the ECU 10 ends the braking force control.

[0098] (Condition B1) The target deceleration TG is zero.

[0099] (Condition B2) The speed Vs of the vehicle VA is zero.

[0100] (Working Example 1)

[0101] Use Figure 5 and Figure 6 to explain Working Example 1 of the vehicle control device. In the example of Figure 5 , the vehicle VA is traveling on the road RD. The road RD is a one-way dual-lane road, including a first driving lane Ln1 and a second driving lane Ln2. Most of the second driving lane Ln2 is omitted. The first driving lane Ln1 is defined by a left dividing line LL and a right dividing line RL. The vehicle VA is traveling in the first driving lane Ln1.

[0102] <Time t0>

[0103] At time t0, the center position O of the vehicle VA is located at position P0 (refer to Figure 5 ). The ECU10 detects an object (n) existing in the front area of the vehicle VA based on the object information. The ECU10 determines that there is a possibility of collision between the vehicle VA and the object (n), and determines (sets) the object (n) as an obstacle.

[0104] <Time t1>

[0105] At time t1, the center position O of the vehicle VA reaches position P1 (refer to Figure 5 ). At this time, the TTC becomes below the time threshold Tath. The execution condition is satisfied, so the ECU10 starts collision avoidance control. The ECU10 calculates the target path TP and starts steering control. Moreover, the ECU10 starts braking force control. The ECU10 sets the control state to the first state 401 and executes the first deceleration control. As shown in Figure 6 , the ECU10 sets the target deceleration TG to the deceleration da1 (negative acceleration) to decelerate the vehicle VA. Therefore, after time t1, the speed Vs of the vehicle VA gradually decreases.

[0106] <Time t2>

[0107] At time t2, the center position O of the vehicle VA reaches position P2 (refer to Figure 5 ). At this time, the steering end condition is satisfied. The ECU10 ends the steering control. After ending the steering control, the ECU10 also continues the braking force control as described below. Specifically, as shown in Figure 4As shown, the ECU 10 changes the control state from the first state 401 to the second state 402. The ECU 10 executes the second deceleration control instead of the first deceleration control. That is, the ECU 10 switches the braking force control from the first deceleration control to the second deceleration control. After time t2, the ECU 10 calculates the target deceleration TG according to the following formula (1) every time the time dT elapses.

[0108] TG←TG+ΔG1……(1)

[0109] Therefore, after time t2, the magnitude of the target deceleration TG decreases at the first inclination.

[0110] <Time t3>

[0111] At time t3, the center position O of the vehicle VA reaches the position P3 (refer to Figure 5 ). As Figure 6 shown, at this time, the speed Vs is not zero. However, the target deceleration TG is zero. Therefore, the braking end condition is satisfied. The ECU 10 ends the braking force control (the second deceleration control in this example).

[0112] According to this configuration, when the steering end condition is satisfied, the ECU 10 ends the steering control and ends the braking force control by reducing the magnitude of the target deceleration TG at the first inclination. After the steering control ends, the magnitude of the target deceleration TG does not suddenly become zero but gradually decreases. Therefore, the possibility of the driver feeling discomfort can be reduced.

[0113] (Operating Example 2)

[0114] Using Figure 5 and Figure 7 , the operating example 2 of the vehicle control device will be described. The operating example 2 corresponds to the situation of (a) above. It should be noted that the processing until time t1 is the same as that in the operating example 1, so the description is omitted. The processing after time t1 will be described.

[0115] <Time t1a>

[0116] At time t1a, the center position O of the vehicle VA reaches the position P1a (refer to Figure 5)。At this time, in order to avoid a collision with the object (n), the driver attempts to move the vehicle VA from the first driving lane Ln1 to the second driving lane Ln2. That is, the driver performs a driving operation to move the vehicle VA in the direction of the arrow Ar1. Specifically, the driver steps on the accelerator pedal 11a while holding the steering wheel SW. As a result, the accelerator pedal operation amount AP becomes equal to or greater than the operation amount threshold APth, and the magnitude of the steering torque Tra becomes equal to or greater than the torque threshold Trth. Therefore, the cancellation condition is satisfied. The ECU10 ends the steering control. After ending the steering control, the ECU10 also continues the braking force control as described below. Specifically, as Figure 4 shown, the ECU10 changes the control state from the first state 401 to the third state 403. The ECU10 performs the third deceleration control instead of the first deceleration control. That is, the ECU10 switches the braking force control from the first deceleration control to the third deceleration control. The ECU10 calculates the target deceleration TG according to the following formula (2) every time the time dT elapses.

[0117] TG←TG + ΔG2……(2)

[0118] Therefore, as Figure 7 shown, after the time t1a, the magnitude of the target deceleration TG decreases at the second inclination.

[0119] <Time t1b>

[0120] At the time t1b, the center position O of the vehicle VA reaches the position P1b (refer to Figure 5 ). As Figure 7 shown, the target deceleration TG is zero. Therefore, the braking end condition is satisfied. The ECU10 ends the braking force control (the third deceleration control in this example). Therefore, after the time t1b, the driving operation of the driver is reflected in the vehicle VA, and the vehicle VA accelerates.

[0121] According to this configuration, when the cancellation condition is satisfied, the ECU10 ends the steering control and ends the braking force control by decreasing the magnitude of the target deceleration TG at the second inclination. When the driver performs a driving operation, the magnitude of the target deceleration TG quickly becomes zero (that is, the braking force control ends quickly). Since the driving operation of the driver is reflected in the vehicle VA, the possibility of the driver feeling discomfort can be reduced.

[0122] (Working Example 3)

[0123] Use Figure 5 and Figure 8, an operation example 3 of the vehicle control device will be described. Operation example 3 corresponds to the situation of (b) above. The processing until time t2 is the same as that in operation example 1, so the description thereof is omitted. The processing after time t2 will be described.

[0124] <Time t2a>

[0125] At time t2a, the center position O of the vehicle VA reaches position P2a (refer to Figure 5 ). The driver steps on the accelerator pedal 11a. Since the accelerator pedal operation amount AP becomes equal to or greater than the operation amount threshold APth, the cancellation condition is satisfied. As Figure 4 shown, the ECU 10 changes the control state from the second state 402 to the third state 403. Therefore, the ECU 10 executes the third deceleration control instead of the second deceleration control. That is, the ECU 10 switches the braking force control from the second deceleration control to the third deceleration control. After time t2a, the ECU 10 calculates the target deceleration TG according to Equation (2) every time the elapsed time is dT.

[0126] Therefore, as Figure 8 shown, after time t2a, the magnitude of the target deceleration TG decreases at the second inclination.

[0127] <Time t2b>

[0128] At time t2b, the center position O of the vehicle VA reaches position P2b (refer to Figure 5 ). As Figure 8 shown, the target deceleration TG is zero. Therefore, the braking end condition is satisfied. The ECU 10 ends the braking force control (the third deceleration control in this example). Therefore, after time t2b, the driving operation of the driver (the operation of the accelerator pedal 11a) is reflected in the vehicle VA, and the vehicle VA accelerates.

[0129] According to this configuration, when the cancellation condition is satisfied after the steering end condition is satisfied, the ECU 10 also ends the braking force control by decreasing the magnitude of the target deceleration TG at the second inclination. When the driver resumes the driving operation after the steering control ends, the braking force control ends faster than in the case of operation example 1. Since the driving operation of the driver is reflected in the vehicle VA, the possibility that the driver feels discomfort can be reduced.

[0130] (Operation)

[0131] The CPU 101 of the ECU 10 (hereinafter, simply referred to as "CPU".) is configured to execute the Figures 9 to 11 routine every time the elapsed time is dT.

[0132] Moreover, every time the time dT elapses, the CPU acquires driving state information from various sensors 11 to 16 and vehicle surrounding information from the surrounding sensors 17, and stores this information in the RAM 103.

[0133] It should be noted that in the initialization routine executed when the ignition switch (not shown) changes from OFF to ON, the CPU sets various flags (XA1, XA2, XB1, and XB2 described later) to "0".

[0134] When it reaches a specified timing, the CPU starts processing from Figure 9 step 900 and enters step 901, and based on the object information, determines whether there is one or more objects in the surrounding area of the vehicle VA. If there are no objects in the surrounding area of the vehicle VA, the CPU determines "No" in step 901 and directly enters step 995 to temporarily end this routine.

[0135] In contrast, assume that the CPU detects an object (n). The CPU determines "Yes" in step 901 and enters step 902. As described above, the CPU determines whether there is a possibility of collision between the vehicle VA and the object (n). If there is no possibility of collision between the vehicle VA and the object (n), the CPU determines "No" in step 902 and directly enters step 995 to temporarily end this routine.

[0136] In contrast, if there is a possibility of collision between the vehicle VA and the object (n), the CPU determines "Yes" in step 902 and enters step 903. The CPU determines whether the above execution conditions are satisfied. Specifically, the CPU determines whether the TTC is less than or equal to the time threshold Tath. If the execution conditions are not satisfied, the CPU determines "No" in step 903 and directly enters step 995 to temporarily end this routine.

[0137] In contrast, if the execution conditions are satisfied, the CPU determines "Yes" in step 903 and enters step 904. In step 904, the CPU sets the flag XA1 to "1" and the flag XB1 to "1". After that, the CPU enters step 995 to temporarily end this routine. For the flag XA1, when its value is "1", it indicates the execution of the Figure 10 routine described later. For the flag XB1, when its value is "1", it indicates the execution of the Figure 11 routine described later.

[0138] Furthermore, when it reaches a specified timing, the CPU executes Figure 10routine. The CPU starts processing from step 1000 and enters step 1001 to determine whether the value of flag XA1 is "1". If the value of flag XA1 is not "1", the CPU determines "No" in step 1001 and directly enters step 1095 to temporarily end this routine.

[0139] Currently, it is assumed that Figure 9 in step 904 of the routine, flag XA1 is set to "1". In this case, the CPU determines "Yes" in step 1001 and enters step 1002 to determine whether the value of flag XA2 is "0". For the value of flag XA2, when its value is "0", it means that the steering control has not been executed, and when its value is "1", it means that the steering control has been executed.

[0140] Currently, the value of flag XA2 is "0", so the CPU determines "Yes" in step 1002 and sequentially executes the processes of steps 1003 to 1005 described below. After that, the CPU enters step 1095 to temporarily end this routine.

[0141] Step 1003: The CPU calculates the target path TP as described above.

[0142] Step 1004: The CPU sets flag XA2 to "1".

[0143] Step 1005: The CPU executes the steering control based on the target path TP. The CPU calculates the target steering torque Atr based on the target path TP and sends a steering instruction signal (including the target steering torque Atr) to the steering ECU 40. The steering ECU 40 drives the auxiliary motor 41 based on the target steering torque Atr.

[0144] After that, when the CPU starts Figure 10 the routine from step 1000 again and enters step 1002, it determines "No" and enters step 1006. The CPU determines in step 1006 whether the above cancellation condition is established. If the cancellation condition is not established, the CPU determines "No" in step 1006 and enters step 1007 to determine whether the above steering end condition is established. If the steering end condition is not established, the CPU determines "No" in step 1007 and enters step 1005 to execute the steering control. Thus, when the cancellation condition and the steering end condition are not established, the CPU continuously performs the steering control.

[0145] When the cancellation condition is established during the period when the CPU repeatedly executes Figure 10 the routine, the CPU determines "Yes" in step 1006 and enters step 1008.

[0146] When the CPU repeatedly executes Figure 10When the end condition of the turn during the routine is satisfied, the CPU determines "Yes" in step 1007 and proceeds to step 1008.

[0147] In step 1008, the CPU sets flag XA1 to "0" and flag XA2 to "0". As a result, the CPU determines "No" in step 1001, and thus the turn control ends.

[0148] Furthermore, when a specified timing is reached, the CPU executes Figure 11 the routine. The CPU starts processing from step 1100 and proceeds to step 1101, where it determines whether the value of flag XB1 is "1". If the value of flag XB1 is not "1", the CPU determines "No" in step 1101 and directly proceeds to step 1195 to temporarily end this routine.

[0149] Currently, it is assumed that Figure 9 in step 904 of the routine, flag XB1 is set to "1". In this case, the CPU determines "Yes" in step 1101 and proceeds to step 1102, where it determines whether the value of flag XB2 is "0". For the value of flag XB2, when its value is "0", it indicates that the braking force control has not been executed, and when its value is "1", it indicates that the braking force control has been executed.

[0150] Currently, the value of flag XB2 is "0", so the CPU determines "Yes" in step 1102 and sequentially executes the processes of steps 1103 and 1104 described below. After that, the CPU proceeds to step 1105.

[0151] Step 1103: The CPU starts the braking force control and then sets the control state to the first state 401.

[0152] Step 1104: The CPU sets flag XB2 to "1".

[0153] In step 1105, the CPU determines which of the first state 401, the second state 402, and the third state 403 the current control state is.

[0154] Currently, the control state is the first state 401, so the CPU sequentially executes the processes of steps 1106 and 1109 as described below. That is, the CPU executes the first deceleration control. After that, the CPU proceeds to step 1195 to temporarily end this routine.

[0155] Step 1106: The CPU sets the target deceleration TG to the deceleration da1.

[0156] Step 1109: The CPU sends a braking instruction signal including the target deceleration TG to the brake ECU 30. The brake ECU 30 controls the brake actuator 31 based on the target deceleration TG.

[0157] After that, when the CPU enters step 1102 again starting from step 1100 Figure 11 in the routine and determines "no", it enters step 1110. The CPU determines whether the above braking end condition is satisfied.

[0158] When the braking end condition is not satisfied, the CPU determines "no" in step 1110 and enters step 1111. The CPU determines the current control state. Specifically, the CPU determines whether the steering end condition or the cancellation condition is satisfied, and thereby Figure 4 changes the control state as shown. When the steering end condition is satisfied, the CPU changes the control state to the second state 402. After that, the CPU enters step 1105. Since the control state is the second state 402, the CPU sequentially executes the processes of step 1107 and step 1109 as described below. That is, the CPU executes the second deceleration control. After that, the CPU enters step 1195 and temporarily ends this routine.

[0159] Step 1107: The CPU calculates the target deceleration TG according to Equation (1).

[0160] Step 1109: The CPU sends a braking instruction signal including the target deceleration TG to the brake ECU 30. The brake ECU 30 controls the brake actuator 31 based on the target deceleration TG.

[0161] On the other hand, when the cancellation condition is satisfied, the CPU changes the control state to the third state 403 in step 1111. After that, the CPU enters step 1105. Since the control state is the third state 403, the CPU sequentially executes the processes of step 1108 and step 1109 as described below. That is, the CPU executes the third deceleration control. After that, the CPU enters step 1195 and temporarily ends this routine.

[0162] Step 1108: The CPU calculates the target deceleration TG according to Equation (2).

[0163] Step 1109: The CPU sends a braking instruction signal including the target deceleration TG to the brake ECU 30. The brake ECU 30 controls the brake actuator 31 based on the target deceleration TG.

[0164] When the CPU repeatedly executes Figure 11When the period braking end condition of the routine is satisfied, the CPU determines "Yes" in step 1110 and proceeds to step 1112. In step 1112, the CPU sets flag XB1 to "0" and flag XB2 to "0". As a result, the CPU determines "No" in step 1101, and thus the braking force control ends.

[0165] The vehicle control device having the above configuration can change the end process of the braking force control according to the situation. When the steering end condition is satisfied, the vehicle control device ends the braking force control by reducing the magnitude of the target deceleration TG at a first inclination. On the other hand, when the cancellation condition is satisfied, the vehicle control device ends the braking force control by reducing the magnitude of the target deceleration TG at a second inclination. As described above, the second inclination is larger than the first inclination. According to this configuration, when the steering end condition is satisfied, the magnitude of the target deceleration TG does not suddenly become zero but gradually decreases. Therefore, the possibility of the driver feeling discomfort can be reduced. Moreover, when the cancellation condition is satisfied (i.e., when the driver performs a driving operation), the magnitude of the target deceleration TG becomes zero faster than when the steering end condition is satisfied. Since the driver's driving operation is reflected in the vehicle VA, the possibility of the driver feeling discomfort can be reduced.

[0166] Moreover, when the cancellation condition is satisfied after the steering end condition is satisfied, the vehicle control device also ends the braking force control by reducing the magnitude of the target deceleration TG at a second inclination. When the driver resumes driving operation after the steering control ends, the braking force control ends quickly. Since the driver's driving operation is reflected in the vehicle VA, the possibility of the driver feeling discomfort can be reduced.

[0167] It should be noted that the present disclosure is not limited to the above-described embodiments, and various modifications can be adopted within the scope of the present disclosure.

[0168] (Modification Example 1)

[0169] The execution condition is not limited to the above example, and it can also be other conditions. For example, the execution condition may further include a condition related to the traveling distance Lx until the vehicle VA stops.

[0170] Specifically, the ECU 10 calculates the traveling distance Lx on the assumption that the vehicle VA decelerates at a deceleration da1 from the current moment. The traveling distance Lx is sometimes also referred to as the braking distance. The traveling distance Lx is calculated by one of various known methods. For example, the ECU 10 calculates the traveling distance Lx based on the speed Vs at the current moment and the deceleration da1, etc.

[0171] ECU 10 can also determine whether the arithmetic expression of the following formula (3) holds. As Figure 3 shown, Dfx(n) is the longitudinal distance up to the obstacle (object (n)). β is a specified distance.

[0172] Lx>(Dfx(n)-β)……(3)

[0173] When formula (3) holds, this means that the vehicle VA cannot stop at a position β away from the object (n) (refer to Figure 3 ), so the possibility of the vehicle VA colliding with the object (n) is high. Therefore, in addition to the above conditions related to TTC, it can also be that when the condition related to the driving distance Lx holds, the ECU 10 determines that the execution condition holds.

[0174] (Variant Example 2)

[0175] It can also be that the collision avoidance control further includes an attention reminder control for reminding the driver. Specifically, when the execution condition holds, the ECU 10 sends an attention reminder instruction signal to the meter ECU 50. When the meter ECU 50 receives the attention reminder instruction signal from the ECU 10, it causes the display 51 to display a mark for attention reminder and causes the speaker 52 to output an alarm sound.

[0176] (Variant Example 3)

[0177] The steering end condition is not limited to the above example. The steering end condition can be any condition for determining that the avoidance of the collision with the object (n) is completed, and it can also be other conditions. The cancellation condition is not limited to the above example. The cancellation condition can be any condition for determining the driving operation by the driver, and it can also be other conditions.

[0178] (Variant Example 4)

[0179] It can also be that the CPU calculates the target steering angle θt as the steering control amount, and the target steering angle θt is the target value of the steering angle θ of the vehicle VA. The CPU sends a steering instruction signal (including the target steering angle θt) to the steering ECU 40. The steering ECU 40 drives the assist motor 41 based on the target steering angle θt.

Claims

1. A vehicle control device, comprising: a sensor configured to acquire object information, the object information being information related to an object in a peripheral area of the vehicle existing in at least a front area of the vehicle ； and a control unit configured to determine whether a prescribed execution condition that holds when there is a high possibility of a collision between the vehicle and the object holds based on the object information, and execute collision avoidance control for avoiding a collision with the object when it is determined that the prescribed execution condition holds, the collision avoidance control at least including: steering control for changing a steering angle of a steering wheel of the vehicle along a target path that is a path for avoiding a collision with the object; and braking force control for applying a braking force to wheels of the vehicle according to a target deceleration, the control unit being configured to: when a prescribed steering end condition that holds when avoidance of a collision with the object is completed by the steering control holds during execution of the collision avoidance control, end the steering control and end the braking force control by decreasing a magnitude of the target deceleration at a first inclination, where the prescribed steering end condition is a condition that holds when avoidance of a collision with the object is completed by the steering control, when a prescribed cancellation condition that holds when a driver of the vehicle performs a driving operation holds during execution of the collision avoidance control, end the steering control and end the braking force control by decreasing the magnitude of the target deceleration at a second inclination, where the prescribed cancellation condition is a condition that holds when the driver of the vehicle performs a driving operation, the second inclination being larger than the first inclination, the control unit being configured to: when the cancellation condition holds during a period in which the magnitude of the target deceleration is decreased at the first inclination after the steering end condition holds, end the braking force control by decreasing the magnitude of the target deceleration at the second inclination.

2. The vehicle control device according to claim 1, wherein the control unit is configured to: determine that the steering end condition holds when the vehicle passes by the side of the object and a state in which a magnitude of the steering angle is equal to or less than a prescribed steering angle value continues for a period equal to or longer than a prescribed duration threshold.

3. The vehicle control device according to claim 1, wherein the control unit is configured to: determine that the cancellation condition holds when at least one of a first condition and a second condition holds, where the first condition is a condition that an operation amount of an accelerator pedal is equal to or more than a prescribed operation amount threshold, and the second condition is a condition that a magnitude of a steering torque applied to a steering shaft by an operation of a steering wheel is equal to or more than a prescribed torque threshold.

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