Collision avoidance device for vehicle

Abstract

The vehicle collision avoidance device (100) includes a driver assistance ECU (10) as a control unit. The driver assistance ECU (10) is configured to perform automatic braking to reduce the concern (S50) if the detection result of the target information acquisition device (18) as a target detection device determines that there is a concern that the vehicle (102) may collide with an obstacle (S10). The driver assistance ECU (10) is configured to determine whether a specific condition is met when the accelerator opening (A) based on the driver's driving operation is at least a reference opening (Ac) when the automatic braking ends. If the specific condition is met (S60 to S80), the driver assistance ECU (10) controls the driving force (Fd) of the vehicle such that the vehicle speed (V) does not exceed the upper limit of the vehicle speed range (Vu) for which automatic braking is performed (S90 to S120).

Description

Technical Field

[0001] This invention relates to a collision avoidance device for automobiles and other vehicles. Background Technology

[0002] As one of the collision avoidance devices for automobiles and other vehicles, there is a known collision avoidance device configured as follows: when there is a concern that the vehicle may collide with an obstacle, the concern is reduced by automatic braking; if it is determined that the concern about the collision has disappeared, the automatic braking is terminated.

[0003] For example, Patent Document 1 describes a collision avoidance device configured to reduce the risk of collision by automatic braking when there is a risk of collision, and to control the engine to rise in such a way that the engine driving force does not exceed a preset limit driving force when it is determined that a collision has been avoided.

[0004] According to this collision avoidance device, it is possible to prevent the engine driving force from exceeding the preset limit driving force after avoiding a collision with an obstacle, thereby preventing the vehicle from suddenly starting after collision avoidance.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2012-61932 Summary of the Invention

[0008] [The problem that the invention aims to solve]

[0009] When there is concern about a collision between the vehicle and an obstacle, drivers may sometimes mistakenly press the accelerator pedal instead of the brake pedal. In this situation, the accelerator pedal opening increases rapidly and becomes fully open.

[0010] In conventional collision avoidance devices like the one described in Patent Document 1, if a collision is determined to have been avoided, the system controls the engine to increase its speed so that the engine driving force does not exceed a preset limit. However, if the engine driving force increases, the vehicle speed gradually increases, and sometimes the vehicle speed increases against the driver's wishes.

[0011] In particular, if the vehicle speed is not below the preset upper limit speed, the automatic braking for collision avoidance will not be activated. Even if there is a renewed concern that the vehicle may collide with an obstacle, the automatic braking may not be activated because the vehicle speed exceeds the upper limit speed, thus making it impossible to avoid a collision.

[0012] The present invention provides a collision avoidance device that is improved to prevent a collision even after the automatic braking performed when the vehicle speed is below the maximum vehicle speed has ended and there is a concern that the vehicle may collide with an obstacle again.

[0013] [The means used to solve the problem and the effects of the invention]

[0014] According to the present invention, a collision avoidance device (100) for a vehicle is provided, comprising: an object detection device (object information acquisition device 18) that detects at least an object in front of the vehicle (102); and a control unit (driving assistance ECU 10) configured to perform automatic braking to reduce the concern if the detection result of the object detection device determines that there is a concern that the vehicle may collide with an obstacle (S10).

[0015] The control unit (driving assistance ECU 10) is configured to determine whether a specific condition is met when the accelerator opening (A) based on the driver's driving operation is at or above the reference opening (Ac) after the automatic braking ends, and when the specific condition is met (S60 to S80), control the driving force (Fd) of the vehicle (102) in such a way that the vehicle speed (V) does not exceed the upper limit speed (Vu) of the vehicle speed range in which the automatic braking is performed (S90 to S120).

[0016] Based on the aforementioned collision avoidance device, it is determined whether a specific condition is met: the accelerator opening based on the driver's driving operation is at or above a reference opening at the end of automatic braking. If the specific condition is met, the driving force of the vehicle is controlled such that the vehicle speed does not exceed the upper limit of the speed range for which automatic braking is performed.

[0017] Therefore, if certain conditions are met when automatic braking ends, the vehicle's speed will not exceed the maximum speed limit. Thus, even if a concern arises again about the vehicle colliding with an obstacle after automatic braking ends, automatic braking is executed once this concern is determined, allowing the vehicle to slow down and avoid a collision.

[0018] [Method of Invention]

[0019] In one embodiment of the invention, the control unit (driving assistance ECU 10) is configured to control the driving force of the vehicle in a manner that limits the temporal increase of the driving force when it is determined that a specific condition is not met (S80, S130 to S170).

[0020] Based on the above method, when a specific condition is determined not to be met, the vehicle's driving force is controlled by limiting the time-dependent increase in driving force. Therefore, it is possible to limit the rate of increase in driving force after automatic braking ends, without the driver mistakenly pressing the accelerator pedal as the brake pedal, thereby preventing a rapid increase in vehicle speed.

[0021] In another embodiment of the invention, the control unit (driving assistance ECU 10) is configured to limit the temporal increase of the driving force (ΔFdl) such that the driving force of the vehicle (Fd) is less than the driving force (Fda) based on the accelerator opening (A) when the vehicle speed (V) is less than a reference speed (Vre) which is lower than the upper limit speed (Vu); to make the temporal increase of the driving force 0 when the vehicle speed is the reference speed; and to make the temporal increase of the driving force negative when the vehicle speed exceeds the reference speed. Thus, the driving force is controlled such that the vehicle speed does not exceed the upper limit speed (S90, S100).

[0022] According to the above method, when the vehicle speed is lower than a reference speed which is lower than the upper limit speed, the time-dependent increase in driving force is limited by ensuring that the driving force of the vehicle is less than the driving force based on the accelerator opening. When the vehicle speed is at the reference speed, the time-dependent increase in driving force is set to 0; when the vehicle speed exceeds the reference speed, the time-dependent increase in driving force is set to a negative value.

[0023] Therefore, the timing increase of the driving force can be controlled based on the relationship between the vehicle's speed and a reference speed lower than the upper speed limit. Thus, it is possible to reliably prevent the vehicle's speed from exceeding the upper speed limit.

[0024] In another embodiment of the invention, the control unit (driving assistance ECU 10) is configured to terminate automatic braking (S60) when the vehicle has been stopped for more than the end reference time.

[0025] According to the above method, automatic braking ends when the vehicle remains stationary for a period of time or longer. Therefore, compared to the case where automatic braking ends when the vehicle is determined to be stationary without considering the duration of the stationary state, automatic braking can reliably end when the concern about a collision between the vehicle and an obstacle disappears.

[0026] In another embodiment of the invention, the control unit (driving assistance ECU 10) is configured to determine that a specific condition is met (S80) when the accelerator opening is above a reference opening for a reference duration or longer.

[0027] According to the above technical solution, when the accelerator opening is above the reference opening for a reference duration, it is determined that a specific condition is met. Therefore, compared with determining that a specific condition is met without judging the duration of the accelerator opening being above the reference opening, it is possible to accurately determine that the accelerator opening is above the reference opening.

[0028] In the foregoing description, to aid in understanding the present invention, the names and / or reference numerals used in the embodiments described below are enclosed in brackets to indicate the components of the invention. However, the constituent elements of the present invention are not limited to the constituent elements of the embodiments corresponding to the names and / or reference numerals enclosed in brackets. Other objects, features, and incidental advantages of the present invention will be readily understood from the description of the embodiments of the present invention as illustrated in the following drawings. Attached Figure Description

[0029] Figure 1 This is a schematic configuration diagram illustrating an embodiment of the collision avoidance device for vehicles according to the present invention.

[0030] Figure 2 This is a flowchart corresponding to the collision avoidance control procedure in the implementation method.

[0031] Figure 3 It is a graph corresponding to the mapping used to calculate the limiting additive driving force ΔFdl based on vehicle speed V when the accelerator opening A is the reference opening Ac or above.

[0032] Figure 4 It is a graph corresponding to the mapping used to calculate the limiting additive driving force ΔFdl based on vehicle speed V when the accelerator opening A is less than the reference opening Ac.

[0033] Figure 5 This is a timing diagram illustrating an example of the operation of an implementation where the accelerator opening A is greater than or equal to the reference opening Ac.

[0034] Figure 6 This is a timing diagram illustrating an example of the operation of an implementation when the accelerator opening A is less than the reference opening Ac. Detailed Implementation

[0035] Hereinafter, the collision avoidance device according to the embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0036] like Figure 1As shown, the driving control device 100 according to the embodiments of the present invention is applied to a vehicle 102 and includes a driving assistance ECU 10. The vehicle 102 is a vehicle capable of autonomous driving and includes a drive ECU 20, a brake ECU 30, and an instrument ECU 50. An ECU refers to an Electronic Control Unit (ECU) with a microcomputer as its main component. To distinguish it from other vehicles, the vehicle 102 is referred to as this vehicle 102 as needed.

[0037] Each ECU's microcomputer includes a CPU, ROM, RAM, read / write non-volatile memory (N / M), and interfaces (I / F). The CPU executes instructions (programs, routines) stored in the ROM to perform various functions. Furthermore, these ECUs are interconnected via CAN (Controller Area Network) 104 to exchange data (communication). Therefore, the detection values ​​of sensors (including switches) connected to a specific ECU are also sent to other ECUs.

[0038] The driver assistance ECU 10 is a central control device for driving control, including collision avoidance control, following distance control, and lane keeping control. In this embodiment, as detailed later, the driver assistance ECU 10 collaborates with other ECUs to perform driving control for the vehicle 102. In the collision avoidance control of this embodiment, if the driver assistance ECU 10 determines that there is a possibility of collision with an obstacle located in front of the vehicle in its direction of travel, it issues a warning of this possibility. Furthermore, an obstacle is an object that would cause damage to the vehicle and / or other vehicles if collided with, such as a stopped vehicle, a slow-moving vehicle, or a pedestrian crossing the road.

[0039] Furthermore, if the driver assistance ECU 10 determines that the possibility of a collision with the vehicle has increased and there is a concern about a collision, it will execute automatic braking to reduce this concern. Additionally, automatic braking is executed when the vehicle's speed V is below the maximum speed limit Vu. Therefore, the maximum speed limit Vu is the upper limit of the speed range at which automatic braking is executed.

[0040] The driver assistance ECU 10 is connected to a camera sensor 12, a radar sensor 14, and a setting operator 16. The camera sensor 12 and the radar sensor 14 each include multiple camera devices and multiple radar devices. The camera sensor 12 and the radar sensor 14 function as a target information acquisition device 18 to obtain at least target information in front of the vehicle 102.

[0041] Although not shown in the diagram, each camera device of the camera sensor 12 includes a camera unit that captures images of the area around the vehicle 102 and an identification unit that analyzes the image data captured by the camera unit to identify targets such as road lines and other vehicles. The identification unit supplies information related to the identified targets to the driver assistance ECU 10 at predetermined intervals.

[0042] Each radar device in radar sensor 14 includes a radar transceiver unit and a signal processing unit (not shown). The radar transceiver unit transmits millimeter-wave radio waves (hereinafter referred to as "millimeter waves") and receives millimeter waves (i.e., reflected waves) reflected by three-dimensional objects (e.g., other vehicles, bicycles, etc.) within the transmission range. Based on the phase difference between the transmitted millimeter waves and the received reflected waves, the attenuation level of the reflected waves, and the time from transmitting the millimeter waves to receiving the reflected waves, the signal processing unit supplies the driver assistance ECU 10 with information such as the distance between the vehicle and the three-dimensional object, the relative speed between the vehicle and the three-dimensional object, and the relative position (direction) of the three-dimensional object relative to the vehicle at predetermined intervals. Alternatively, LiDAR (Light Detection and Ranging) can be used instead of radar sensor 14, or based on radar sensor 14.

[0043] Setting the operator 16, for example Figure 1 The steering wheel, not shown, is positioned in a location where it can be operated by the driver. Although... Figure 1 Not shown in the diagram, but the setting operator 16 includes a collision avoidance switch. As detailed later, the driver assistance ECU 10 performs collision avoidance control when the collision avoidance switch is activated.

[0044] The drive ECU 20 is connected to a drive unit 22 that accelerates the vehicle 102 by applying driving force to the drive wheels 24. The drive ECU 20 normally controls the drive unit 22 so that the driving force generated by the drive unit 22 varies according to the driver's driving operation. If a command signal is received from the driving assistance ECU 10, the drive unit 22 is controlled based on the command signal.

[0045] The braking ECU 30 is connected to a braking device 32 that decelerates the vehicle 102 by applying braking force to the wheels 34. Normally, the braking ECU 30 controls the braking device so that the braking force generated by the braking device 32 varies according to the driver's braking operation. If a command signal is received from the driver assistance ECU 10, the braking device 32 is controlled based on the command signal to perform automatic braking. Furthermore, as described above, automatic braking to avoid collisions with obstacles is performed when the vehicle speed V is below the upper limit speed Vu.

[0046] Therefore, the braking ECU 30 and the braking device 32 cooperate to function as the automatic braking device 36. Furthermore, when applying braking force to the wheels through automatic braking or the like, Figure 1 The brake lights, not shown, are illuminated.

[0047] The instrument cluster ECU 50 is connected to a touch panel-type display 52 that displays the control status of the driver assistance ECU 10, and an alarm device 54 that issues warnings. The display 52 may be, for example, a multi-information display showing instrument cluster information and various other information, or a display for a navigation device. As will be described later, if the display 52 receives a signal from the driver assistance ECU 10, it displays the collision avoidance control status.

[0048] The alarm device 54 activates when it determines that there is a possibility of a collision between vehicle 102 and an obstacle, issuing an alarm indicating that there is a possibility of a collision between vehicle 102 and an obstacle. Furthermore, the alarm device 54 activates when it determines that there is a concern about a potential collision between vehicle 102 and an obstacle, issuing an alarm indicating that there is a concern about a potential collision between vehicle 102 and an obstacle. The alarm device 54 can be any one of the following: a visual alarm device such as a warning light; an auditory alarm device such as a siren buzzer; or a haptic alarm device such as seat vibration; or any combination thereof. Additionally, the alarm indicating a concern about a potential collision between vehicle 102 and an obstacle has a higher appeal level than the alarm indicating a possibility of a collision between vehicle 102 and an obstacle.

[0049] The driving operation sensor 60 and the vehicle status sensor 70 are also connected to the CAN 104. Information detected by the driving operation sensor 60 and the vehicle status sensor 70 (referred to as sensor information) is sent to the CAN 104. The sensor information sent to the CAN 104 can be appropriately utilized by each ECU. Alternatively, the sensor information can also be information from sensors connected to a specific ECU, sent from that specific ECU to the CAN 104.

[0050] The driving operation sensor 60 includes an accelerator opening sensor that detects the accelerator opening A (0-100%) as the amount of operation of the accelerator pedal, a brake operation amount sensor that detects the master cylinder pressure or the force Fbp applied to the brake pedal, and a brake switch that detects the presence or absence of brake pedal operation. Furthermore, the driving operation sensor 60 includes a steering angle sensor that detects the steering angle, a steering torque sensor that detects the steering torque, and so on.

[0051] The vehicle status sensor 70 includes a vehicle speed sensor for detecting the vehicle speed V of the vehicle 102, a front-rear acceleration sensor for detecting the vehicle's front-to-back acceleration Gx, a lateral acceleration sensor for detecting the vehicle's lateral acceleration, and a yaw rate sensor for detecting the vehicle's yaw rate.

[0052] In the implementation, the ROM of the driving assistance ECU 10 stores information related to... Figure 2 The flowchart shown corresponds to the collision avoidance control program. Furthermore, in this embodiment, the ROM of the driver assistance ECU 10 stores... Figure 3 as well as Figure 4 The diagram shown corresponds to a mapping.

[0053] Collision Avoidance Control

[0054] Next, refer to Figure 2 The flowchart shown illustrates the collision avoidance control routine in the implementation embodiment. When the collision avoidance assist switch is activated, the CPU of the driver assistance ECU 10 repeatedly executes the routine at predetermined intervals. Figure 2 The flowchart shown illustrates the control process.

[0055] First, in step S10, the CPU obtains, for example, information about the relative distance Lr between the vehicle and the obstacle, and the relative speed Vr of the vehicle relative to the obstacle, detected by the camera sensor 12 or the radar sensor 14. Then, based on the relative distance Lr and the relative speed Vr, the CPU determines whether there is a risk of collision between the vehicle and the obstacle. If a positive determination is made, the control proceeds to step S30; if a negative determination is made, the control proceeds to step S20.

[0056] Furthermore, the predicted time until the vehicle collides with the obstacle, also known as the Collision Prediction Time (TTC), is calculated by dividing the relative distance Lr by the relative speed Vr. When the TTC is below the first reference value TTC1 (a positive constant), a risk of collision between the vehicle and the obstacle is considered. The Collision Prediction Time (TTC) is an indicator of the likelihood of the vehicle colliding with an obstacle; the smaller the value, the higher the risk of collision.

[0057] In step S20, the CPU determines whether there is a possibility of the vehicle colliding with an obstacle based on the relative distance Lr and the relative velocity Vr. If a negative determination is made, the control temporarily ends; if a positive determination is made, the control proceeds to step S40. Furthermore, if the TTC is below the second reference value TTC2 (a positive constant greater than the first reference value TTC1), it is determined that there is a possibility of the vehicle colliding with an obstacle.

[0058] In step S30, the CPU determines whether the vehicle speed V detected by the vehicle speed sensor is below the upper limit vehicle speed Vu (e.g., a positive constant of 15 km / h). If an affirmative determination is made, the control proceeds to step S50; if a negative determination is made, the control proceeds to step S40.

[0059] In step S40, the CPU outputs a command signal to the instrument ECU 50, thereby displaying an alarm on the display 52 indicating the possibility of a collision between the vehicle and an obstacle, and activating the alarm device 54 to issue an alarm indicating the possibility of a collision between the vehicle and an obstacle.

[0060] Furthermore, if step S40 is executed after a negative determination in step S30, an alarm indicating a concern that the vehicle may collide with an obstacle is displayed on the display 52, and the alarm device 54 activates, issuing an alarm indicating a concern that the vehicle may collide with an obstacle. Additionally, the alarm issued after a negative determination in step S30 and execution of step S40 has a higher appeal level than the alarm issued after a positive determination in step S20 and execution of step S40.

[0061] In step S50, the CPU calculates a target deceleration Gbt for the vehicle to prevent a collision with the obstacle based on the relative distance Lr between the vehicle 102 and the obstacle and the relative speed Vr of the vehicle relative to the obstacle. Furthermore, the CPU outputs a command signal to the braking ECU 30 to decelerate the vehicle at the target deceleration Gbt, thereby executing automatic braking based on the automatic braking device 36 in such a way that the vehicle's deceleration becomes the target deceleration Gbt.

[0062] In step S60, the CPU determines whether the automatic braking system used to prevent the vehicle from colliding with an obstacle should be terminated. If a negative determination is made, the control returns to step S50; if a positive determination is made, the control proceeds to step S70. Alternatively, the automatic braking system may be terminated if the vehicle has been stopped for more than a specified end reference time te (a positive constant) or if it is determined that there is no possibility of the vehicle colliding with an obstacle.

[0063] In step S70, the CPU determines whether the driver has performed a driving operation while the vehicle is stationary. If a negative determination is made, the control temporarily terminates; if a positive determination is made, the control proceeds to step S80. Alternatively, the driver can be identified as performing a driving operation if the accelerator opening A is not 0 but a positive value.

[0064] In step S80, the CPU determines whether, before and after the moment the vehicle stops, the accelerator opening A is at or above the reference opening Ac (a positive constant of 100% or close to 100%) for a reference duration tc (a positive constant) or more. If a negative determination is made, the control proceeds to step S130; if a positive determination is made, the control proceeds to step S90. Furthermore, if the accelerator opening A is at or above the reference opening Ac until the moment the vehicle stops and its duration is at or above the reference duration tc, a positive determination is also made. Additionally, if the accelerator opening A is at or above the reference opening Ac from the moment the vehicle stops and its duration is at or above the reference duration tc, a positive determination is also made.

[0065] As can be seen from the above description, steps S60 to S80 are steps to determine whether the specific condition of the accelerator opening A based on the driver's driving operation being above the reference opening Ac when the automatic braking ends is met.

[0066] In step S90, the CPU, based on the vehicle speed V, according to... Figure 3 The diagram shown corresponds to a mapping used to calculate the limiting additive driving force ΔFdl. For example... Figure 3 As shown, when the vehicle speed V is above 0 and below V1 (a positive constant), the limiting additive driving force ΔFdl decreases from ΔFdl1 (a positive constant) to ΔFdl2 (a positive constant smaller than ΔFdl1) as the vehicle speed increases. When the vehicle speed V is above V1 and below V2 (a positive constant larger than V1), the limiting additive driving force ΔFdl remains ΔFdl2 regardless of the vehicle speed. When the vehicle speed V is above V2 and below the reference vehicle speed Vre (a positive constant larger than V2 and smaller than the upper limit vehicle speed Vu), it decreases from ΔFdl2 to 0 as the vehicle speed increases. Furthermore, when the vehicle speed V is above the reference vehicle speed Vre, the limiting additive driving force ΔFdl decreases from 0 as the vehicle speed increases (becoming a negative value with an increasing absolute value).

[0067] In step S100, the CPU calculates the limiting driving force Fdl as the sum of the previous value of the driving force Fdf and the limiting driving force ΔFdl, i.e., Fdf + ΔFdl. Furthermore, the CPU controls the driving force by outputting a command signal to the drive ECU 20, thereby making the vehicle's driving force Fd the limiting driving force Fdl.

[0068] In step S110, the CPU determines, in the same way as in step S70, whether the driving operation was performed by the driver. If a positive determination is made, the control returns to step S90; if a negative determination is made, the control proceeds to step 120.

[0069] In step S120, the CPU terminates the control of the driving force of the vehicle, that is, it controls the driving force Fd of the vehicle to the limited driving force Fdl.

[0070] In step S130, the CPU calculates the driving force Fda based on the accelerator opening A using methods known in the art. The larger the accelerator opening A, the larger the driving force Fda.

[0071] In step S140, the CPU, based on the vehicle speed V, according to... Figure 4 The graph shown by the solid line corresponds to the mapping used to calculate the limiting additive driving force ΔFdl. For example... Figure 4 As shown by the solid line, when the vehicle speed V is above 0 and less than V3 (a positive constant), the limiting additive driving force ΔFdl decreases from ΔFdl3 (a positive constant) to ΔFdl4 (a positive constant smaller than ΔFdl3) as the vehicle speed increases. When the vehicle speed V is above V3, the limiting additive driving force ΔFdl is always ΔFdl4, regardless of the vehicle speed. Furthermore, ΔFdl3 and ΔFdl4 can be the same as ΔFdl1 and ΔFdl2, respectively, and V3 can be the same as V1.

[0072] In step S150, the CPU calculates the limiting driving force Fdl as the sum of the previous value of the driving force Fdf and the limiting additive driving force ΔFdl, i.e., Fdf + ΔFdl. Furthermore, the CPU determines whether the driving force Fda based on the accelerator opening A is greater than or equal to the limiting additive driving force ΔFdl. If a negative determination is made, the control proceeds to step S170; if a positive determination is made, the control proceeds to step S160.

[0073] In step S160, the CPU outputs a command signal to the drive ECU 20 to control the driving force so that the driving force Fd of the vehicle becomes the limiting driving force Fdl. Conversely, in step S170, the CPU outputs a command signal to the drive ECU 20 to control the driving force so that the driving force Fd of the vehicle becomes the driving force Fda based on the accelerator opening A.

[0074] <Examples of actions in the implementation method>

[0075] 1. The case where a positive determination is made in step S80 ( Figure 5 )

[0076] like Figure 5As shown, at time t1, the determinations in steps S10 and S30 become affirmative, and automatic braking begins. At time t2, the vehicle speed V becomes 0, and at time t3, automatic braking ends. The braking force Fb based on automatic braking increases sharply at time t1, becomes Fba from time t1 to time t3, and then becomes 0 immediately after time t3, after which the braking force Fb also becomes 0. The driving force Fd of vehicle 102 begins to decrease sharply at time t1, and becomes 0 from time t1 to time t3. Furthermore, the aforementioned changes in vehicle speed V, braking force Fb, and driving force Fd will be described later. Figure 6 The same applies to China.

[0077] Immediately before time t1, the driver mistakenly presses the accelerator pedal instead of the brake pedal, causing the accelerator opening A to reach 100% before time t2, and thereafter the accelerator opening A remains at 100%.

[0078] At time t3, the decisions in steps S60 and S70 become affirmative, and an affirmative decision is made in step S80, repeatedly executing steps S90 to S110. Therefore, the increase in the driving force Fd of vehicle 102 is based on... Figure 3 The limits are calculated by adding the driving force ΔFdl corresponding to the mapping operation shown in the graph. The vehicle speed V gradually increases after time t3.

[0079] At time t4, when the vehicle speed V reaches the reference speed Vre, the limiting additive driving force ΔFdl becomes 0. Immediately after time t4, the limiting additive driving force ΔFdl becomes negative, and the driving force Fd decreases. Subsequently, if the vehicle speed V fluctuates around the reference speed Vre, the limiting additive driving force ΔFdl fluctuates between negative and positive values, so the vehicle speed V is effectively maintained at the reference speed Vre.

[0080] Therefore, the vehicle speed V will not exceed the upper limit vehicle speed Vu, which is higher than the reference vehicle speed Vre. Therefore, it is possible to prevent a situation where, although there is an obstacle in front of the vehicle 102 again and a positive determination is made in step S10, a negative determination is made in step S30, and it is possible to prevent the automatic braking in step S50 from not being executed.

[0081] 2. The case where a negative determination is made in step S80 ( Figure 6 )

[0082] like Figure 6 As shown, without sharp depressing of the accelerator pedal, the accelerator opening A remains constant at Ae%. After time t3, the decisions in steps S60 and S70 become affirmative, but a negative decision is made in step S80. Therefore, due to the execution of steps S130 to S170, the increase in the driving force Fd of vehicle 102 is based on... Figure 4The constraints corresponding to the mapping calculations shown in the diagram are added together with the driving force ΔFdl to form a constraint.

[0083] The driving force Fd and vehicle speed V of vehicle 102 gradually increase after time t3. After time t5, vehicle speed V exceeds the reference speed Vre, and after time t6, it exceeds the upper limit speed Vu. The sum of the previous value of the driving force Fdf and the limiting driving force ΔFdl, i.e., the limiting driving force Fdl, becomes greater than the driving force Fda based on the accelerator opening A after time t7. The driving force Fd of vehicle 102 is controlled as the limiting driving force Fdl after time t3 and before time 7, and is controlled as the driving force Fda based on the accelerator opening A after time t7.

[0084] Therefore, even when the accelerator opening A is a large value, as long as the accelerator opening A is less than the reference opening Ac, the increase in the driving force Fd and vehicle speed V of vehicle 102 is suppressed, preventing them from increasing sharply. Therefore, compared to the case where the increase in driving force Fd is not suppressed, the moment t6 when vehicle speed V becomes greater than the upper limit vehicle speed Vu can be delayed, thereby delaying the moment of the negative determination in step S30. Therefore, the moment when vehicle speed V becomes greater than the upper limit vehicle speed Vu and automatic braking for collision avoidance is delayed. Furthermore, it is possible to prevent the driving force Fd from becoming greater than the driving force Fda based on the accelerator opening A.

[0085] In addition, Figure 6 The accelerator opening A is constant, but if the accelerator opening A varies within a range smaller than the reference opening Ac, a negative determination is also made in step S30. Therefore, the vehicle speed V, braking force Fb, and driving force Fd, in addition to varying according to the accelerator opening A, are all related to... Figure 6 The same changes.

[0086] <Examples of previous collision avoidance control>

[0087] For example, regarding the situation where a driver mistakenly presses the accelerator pedal as the brake pedal and continues to press it forcefully, the operation of a conventional collision avoidance device like the one described in Patent Document 1 will be explained.

[0088] In conventional collision avoidance devices, after a positive determination is made in step S60, steps S70 and S80 are not performed; instead, the same control as after step S130 is performed. Therefore, in Figure 5 As shown by the dashed line, the driving force Fd of vehicle 102 increases sharply after time t3, becoming a driving force Fda based on the accelerator opening A. As a result, the vehicle speed V increases sharply after time t3, compared to time t4 and... Figure 6At times t5 and t6, for example, at time t8 and later, the vehicle speed V becomes higher than the upper limit vehicle speed Vu. Therefore, when the situation again becomes one where there is an obstacle in front of the vehicle 102 and a positive determination is made in step S10, a negative determination is made in step S30, so the automatic braking in step S50 is not executed. Therefore, it is impossible to avoid a collision with the obstacle through automatic braking.

[0089] As can be seen from the above description, according to the implementation method, it is determined whether a specific condition is met (S60 to S80) that the accelerator opening A based on the driver's driving operation is at or above the reference opening Ac when the automatic braking ends. When the specific condition is determined to be met, the driving force Fd of the vehicle is controlled in such a way that the vehicle speed V does not exceed the upper limit speed Vu of the vehicle speed range in which the automatic braking is performed (S90 to S120).

[0090] Therefore, if certain conditions are met when automatic braking ends, the vehicle's speed V will not exceed the maximum speed limit Vu. Thus, even if a concern arises again about the vehicle colliding with an obstacle after automatic braking ends, automatic braking is executed once the concern is determined, thereby slowing the vehicle down to avoid a collision with the obstacle.

[0091] Furthermore, according to the implementation method, when it is determined that a specific condition is not met, the driving force Fd of the vehicle is controlled by limiting the time-dependent increase in driving force ΔFdl (S80, S130 to S170). Therefore, it is possible to limit the rate of increase in driving force after automatic braking ends, without the driver mistakenly pressing the accelerator pedal as the brake pedal, thereby preventing a sharp increase in vehicle speed.

[0092] Furthermore, according to the implementation method, when the vehicle speed V is less than a reference speed Vre that is lower than the upper limit speed Vu, the time-dependent increase in driving force ΔFdl is limited such that the driving force Fd of the vehicle becomes less than the driving force Fda based on the accelerator opening. When the vehicle speed is the reference speed, the time-dependent increase in driving force is set to 0; when the vehicle speed exceeds the reference speed, the time-dependent increase in driving force is set to a negative value.

[0093] Therefore, the time-dependent increase in driving force ΔFdl can be controlled based on the relationship between the vehicle speed V and a reference speed Vre, which is lower than the upper limit speed Vu. Thus, it is possible to reliably prevent the vehicle speed V from exceeding the upper limit speed Vu.

[0094] Furthermore, according to the embodiment, automatic braking is terminated when the vehicle remains stationary for a period of time te or longer. Therefore, compared to the case where automatic braking is terminated when the vehicle is determined to be stationary without determining the duration of the stationary state, automatic braking can be reliably terminated when the concern about a collision between the vehicle and an obstacle has disappeared.

[0095] Furthermore, according to the implementation method, when the accelerator opening A is at or above the reference opening Ac for a reference duration tc or more, it is determined that a specific condition has been met. Therefore, compared to determining that a specific condition has been met without considering the duration of the accelerator opening being at or above the reference opening, it is possible to accurately determine that the accelerator opening is at or above the reference opening.

[0096] The present invention has been described in detail above with respect to specific embodiments, but the present invention is not limited to the embodiments described above. Various other embodiments can be carried out within the scope of the present invention, which will be obvious to those skilled in the art.

[0097] For example, in the above-described embodiments, based on and Figure 4 The graph shown by the solid line corresponds to a constant additive driving force ΔFdl calculated based on the mapping. When the vehicle speed V is above V3, regardless of the actual vehicle speed, the additive driving force ΔFdl remains constant at ΔFdl4. The additive driving force ΔFdl can also be calculated as follows: Figure 4 As shown by the dashed line, when the vehicle speed V is greater than V3 and lower than the reference vehicle speed Vre (above V4 but less than the reference vehicle speed Vre), it decreases from ΔFdl4 to 0 as the vehicle speed increases, and is 0 when the vehicle speed V is above the reference vehicle speed Vre.

[0098] According to this revised example, when the vehicle speed V is above V4 but below the reference vehicle speed Vre, the rate of increase in driving force decreases as the vehicle speed increases. When the vehicle speed V is above the reference vehicle speed Vre, the driving force does not increase even if the vehicle speed increases. Therefore, the time t7 at which the sum of the previous value of the driving force Fdf and the limiting summed driving force ΔFdl, i.e., the limiting driving force Fdl, becomes greater than the driving force Fda based on the accelerator opening A is delayed compared to the case of the implementation method.

[0099] Furthermore, in the above embodiment, when a negative determination is made in step S80, that is, when it is determined that a specific condition is not met, steps S130 to S170 are executed. However, the restriction on the increase of the driving force Fd of the vehicle 102 when a negative determination is made in step S80 can also be performed according to a method other than steps S130 to S170.

[0100] Furthermore, in the above-described embodiment, when automatic braking is performed, the driving force Fd of vehicle 102 is reduced to 0. However, the driving force Fd may also be reduced to a value higher than 0, or the driving force may not be reduced.

[0101] [Explanation of reference numerals in the attached figures]

[0102] 10…Driver assistance ECU, 12…Camera sensor, 14…Radar sensor, 18…Object information acquisition device, 22…Drive system, 32…Braking system, 36…Automatic braking system, 100…Collision avoidance device, 102…Vehicle

Claims

1. A collision avoidance device for vehicles, comprising: An object detection device that detects at least objects in front of the vehicle; and The control unit is configured to, based on the detection results of the object detection device, determine that there is a risk of collision between the vehicle and an obstacle, and then perform automatic braking to reduce the risk. The control unit is configured to determine whether a specific condition is met when the accelerator opening based on the driver's driving operation is above a reference opening at the end of the automatic braking, and when the specific condition is met, to control the driving force of the vehicle in such a way that the vehicle speed does not exceed the upper limit of the speed range in which the automatic braking is performed.

2. The vehicle collision avoidance device according to claim 1, wherein, The control unit is configured to control the driving force of the vehicle in a manner that limits the temporal increase of the driving force when it is determined that the specific condition is not met.

3. The vehicle collision avoidance device according to claim 1, wherein, The control unit is configured to: when the vehicle speed is less than a reference speed lower than the upper limit speed, limit the time-dependent increase of the driving force by making the driving force of the vehicle less than the driving force based on the accelerator opening; when the vehicle speed is the reference speed, make the time-dependent increase of the driving force zero; and when the vehicle speed exceeds the reference speed, make the time-dependent increase of the driving force negative, thereby controlling the driving force so that the vehicle speed does not exceed the upper limit speed.

4. The vehicle collision avoidance device according to claim 1, wherein, The control unit is configured to terminate the automatic braking when the vehicle has been stopped for more than a specified end time.

5. The vehicle collision avoidance device according to claim 1, wherein, The control unit is configured to determine that the specific condition is met when the accelerator opening is above the reference opening for a reference duration or longer.

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