Vehicle driving assistance apparatus

Abstract

To provide a vehicle driving assistance apparatus that can reduce discomfort to the driver when applying to the own vehicle, the driving force corresponding to the amount of operation of the accelerator pedal when stopping the automatic braking control after stopping the own vehicle by the automatic braking control.SOLUTION: When there is a possibility that an own vehicle 100 collides with an object 200, a vehicle driving assistance apparatus 10 executes driving force limiting control for limiting an applied driving force to a predetermined driving force or less, and also an automatic braking control for automatically braking the own vehicle to stop the own vehicle before the own vehicle collides with the object. After stopping the own vehicle, the vehicle driving assistance device stops the driving force limit control and the automatic braking control and applies a requested driving force to the own vehicle. When applying a driving force greater than the predetermined driving force to the own vehicle, the vehicle driving assistance device executes a driving force restoration control for changing a manner of increasing the applied driving force to the requested driving force according to a relative relation between the own vehicle and the object.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle driving assistance device. [Background technology]

[0002] A vehicle driving assistance device is known that, when there is a possibility that the host vehicle will collide with a target object ahead of the host vehicle, executes driving force limiting control to limit the driving force applied to the host vehicle to a predetermined driving force or less, and also executes automatic braking control to automatically brake the host vehicle and stop the host vehicle before the host vehicle collides with the target. One such vehicle driving assistance device is known that, after the host vehicle is stopped by executing driving force limiting control and automatic braking control, if a predetermined stopping condition is met, stops the driving force limiting control and automatic braking control and applies to the host vehicle a driving force corresponding to the amount of accelerator pedal operation by the driver of the host vehicle (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-109504 Summary of the Invention

[0004] After the host vehicle is stopped by automatic braking control, if a driving force corresponding to the amount of accelerator pedal operation is applied to the host vehicle when the automatic braking control is stopped, if the driving force applied to the host vehicle is increased in the same manner regardless of the relative relationship between the host vehicle and the target, the acceleration of the host vehicle may be extremely small even though the target is not present near the host vehicle, which may cause discomfort to the driver.

[0005] The object of the present invention is to provide a vehicle driving assistance device that can prevent the driver from feeling uncomfortable when a driving force corresponding to the accelerator pedal operation amount is applied to the vehicle after the vehicle has been stopped by automatic braking control and the automatic braking control is stopped.

[0006] A vehicle driving assistance device according to the present invention includes a control device that, when there is a possibility of a collision between a host vehicle and a target object in front of the host vehicle, executes driving force limiting control to limit an additional driving force, which is a driving force applied to the host vehicle, to a predetermined driving force or less, and executes automatic braking control to automatically brake the host vehicle and stop the host vehicle before the host vehicle collides with the target. The control device is configured to stop the driving force limiting control and the automatic braking control when a predetermined stop condition is met after the host vehicle is stopped by executing the driving force limiting control and the automatic braking control, and apply to the host vehicle a requested driving force, which is a driving force corresponding to an accelerator pedal depression amount by the driver of the host vehicle. When the predetermined stop condition is met and a driving force greater than the predetermined driving force is applied to the host vehicle, the control device is configured to execute driving force return control to change how the additional driving force is increased to the requested driving force depending on the relative relationship between the host vehicle and the target object.

[0007] When the vehicle is stopped by automatic braking control and then a requested driving force is added to the vehicle when the automatic braking control is stopped, if the added driving force is increased in the same manner regardless of the relative relationship between the vehicle and the target, the acceleration of the vehicle may be extremely small even though the target is not located near the vehicle, which may cause discomfort to the driver.

[0008] According to the vehicle driving assistance device of the present invention, when a requested driving force is applied to the host vehicle after the host vehicle has been stopped by automatic braking control and the automatic braking control is stopped, the method of increasing the applied driving force up to the requested driving force is changed depending on the relative relationship between the host vehicle and a target object, thereby preventing discomfort to the driver.

[0009] In the vehicle driving assistance device according to the present invention, the relative relationship is, for example, a distance between the host vehicle and the target object. In this case, the control device may be configured to change the manner in which the additional driving force is increased by increasing the gradient of the additional driving force when the distance is equal to or greater than a predetermined distance, compared to when the distance is less than the predetermined distance.

[0010] When the distance between the host vehicle and the target increases, for example, when the target moves away from the host vehicle, slowly increasing the supplemental driving force may cause discomfort to the driver. According to the vehicle driving assistance device of the present invention, when the target moves away from the host vehicle, the supplemental driving force is quickly increased, thereby preventing discomfort to the driver.

[0011] In the vehicle driving assistance device according to the present invention, the control device may be configured to stop the driving force recovery control when the additional driving force reaches the required driving force.

[0012] According to the vehicle driving assistance device of the present invention, it is possible to prevent unnecessary execution of driving force restoration control even after the additional driving force has reached the requested driving force.

[0013] The components of the present invention are not limited to the embodiments of the present invention described below with reference to the drawings. Other objects, features, and attendant advantages of the present invention will be easily understood from the description of the embodiments of the present invention. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing a vehicle driving assistance device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. [Figure 3]FIG. 3 is a flowchart showing a routine executed by the vehicle driving assistance device according to the embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing a scene in which a target exists ahead of the host vehicle. [Figure 5] FIG. 5 is a diagram showing the transition of the driving force applied to the vehicle when the driving force limit control, the automatic braking control, and the driving force recovery control are executed. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a vehicle driving assistance device according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a vehicle driving assistance device 10 according to an embodiment of the present invention. The vehicle driving assistance device 10 is mounted on a host vehicle 100.

[0016] As shown in FIG. 1, the vehicle driving assistance device 10 includes an ECU (electronic control unit) 90 as a control device. The ECU 90 includes a microcomputer as a main component. The microcomputer includes a CPU, storage media such as a ROM, a RAM, and a non-volatile memory, as well as an interface. The CPU executes instructions, programs, or routines stored in the storage media to realize various functions. In particular, in this example, the vehicle driving assistance device 10 stores programs in the storage media that realize various controls executed by the vehicle driving assistance device 10.

[0017] In this example, the vehicle driving assistance device 10 has only one ECU 90, but it may also be configured to have multiple ECUs, with each ECU sharing the functions of the vehicle driving assistance device 10 described below.

[0018] Furthermore, the vehicle driving assistance device 10 may be configured so that the program stored in the storage medium can be updated via wireless communication with an external device (for example, via the Internet).

[0019] The host vehicle 100 is equipped with a drive unit 20 and a brake unit 30. The drive unit 20 and the brake unit 30 are each electrically connected to an ECU 90. The drive unit 20 includes an internal combustion engine and / or a motor generator. The vehicle driving assistance device 10 controls the operation of the drive unit 20 to control the magnitude of the drive force (additional drive force Pa) applied to the host vehicle 100 from the drive unit 20. The brake unit 30 includes a hydraulic brake unit and an electric parking brake unit. The vehicle driving assistance device 10 controls the magnitude of the braking force applied to the host vehicle 100 from the brake unit 30 by controlling the operation of the brake unit 30.

[0020] Furthermore, the host vehicle 100 is equipped with an accelerator pedal 41, an accelerator pedal operation amount sensor 42, a brake pedal 43, a brake pedal operation amount sensor 44, a vehicle speed detection device 45, and a surrounding information detection device 60. The surrounding information detection device 60 includes an electromagnetic wave sensor 61 and an image sensor 62. The accelerator pedal operation amount sensor 42, the brake pedal operation amount sensor 44, the vehicle speed detection device 45, the electromagnetic wave sensor 61, and the image sensor 62 are each electrically connected to the ECU 90.

[0021] The vehicle driving assistance device 10 acquires the operation amount of the accelerator pedal 41 as an accelerator pedal operation amount AP using an accelerator pedal operation amount sensor 42. The vehicle driving assistance device 10 acquires the driving force that is requested to be applied to the host vehicle 100 based on the accelerator pedal operation amount AP and the traveling speed of the host vehicle 100 as a requested driving force Pr. When a first driving force limit control, a second driving force limit control, or a driving force return control, which will be described later, is not being executed, the vehicle driving assistance device 10 controls the operation of the drive device 20 so that the requested driving force Pr is applied to the host vehicle 100.

[0022] Furthermore, the vehicle driving assistance device 10 acquires the operation amount of the brake pedal 43 as the brake pedal operation amount BP using the brake pedal operation amount sensor 44. The vehicle driving assistance device 10 acquires the braking force that is requested to be applied to the host vehicle 100 based on the brake pedal operation amount BP as the requested braking force. When automatic braking control, which will be described later, is not being executed, the vehicle driving assistance device 10 controls the operation of the braking device 30 so that the requested braking force is applied to the host vehicle 100.

[0023] Furthermore, the vehicle driving assistance device 10 acquires the traveling speed of the host vehicle 100 as the host vehicle speed V by the vehicle speed detection device 45.

[0024] The electromagnetic wave sensor 61 is, for example, a radio wave sensor such as a millimeter wave radar or an ultrasonic sensor such as a clearance sonar. The vehicle driving assistance device 10 acquires information (target information IO) relating to targets present ahead of the host vehicle 100 as surrounding information IS using the electromagnetic wave sensor 61. The image sensor 62 is, for example, a camera. The vehicle driving assistance device 10 acquires image information IC of the area ahead of the host vehicle 100 as surrounding information IS using the image sensor 62.

[0025] <Operation of vehicle driving assistance device> Next, a description will be given of the operation of the vehicle driving assistance device 10. The vehicle driving assistance device 10 is configured to execute driving force limit control and automatic braking control as automatic driving control when predetermined conditions are met, to stop the driving force limit control and automatic braking control when another predetermined condition is met after the driving force limit control and the automatic braking control are started, to execute driving force return control as automatic driving control, and to stop the driving force return control when yet another predetermined condition is met.

[0026] The vehicle driving assistance device 10 executes the routines shown in FIGS. 2 and 3 to execute and stop the driving force limit control and the automatic braking control, and to execute and stop the driving force return control.

[0027] The vehicle driving assistance device 10 is configured to execute the routine shown in Fig. 2 at predetermined time intervals. Therefore, when the processing timing arrives, the vehicle driving assistance device 10 starts the processing from step S200 of the routine shown in Fig. 2, and proceeds to step S205, where it determines whether or not the first collision condition CC1 is satisfied.

[0028] As shown in Fig. 4, the first collision condition CC1 is a condition that there is a possibility that the host vehicle 100 will collide with the target 200 in a situation where the target 200 is present on the path of the host vehicle 100 ahead in the traveling direction of the host vehicle 100, and more specifically, a condition that the target distance D is equal to or less than a first distance threshold D1 and is greater than a second distance threshold D2. The target distance D is the distance between the host vehicle 100 and the target 200. The vehicle driving assistance device 10 detects the target 200 based on the surrounding information IS, and acquires the target distance D based on the surrounding information IS.

[0029] The first distance threshold D1 is set to a value greater than the second distance threshold D2. Although the first distance threshold D1 and the second distance threshold D2 may each be constant values ​​independent of the host vehicle speed V, in this example, the first distance threshold D1 and the second distance threshold D2 are set to a longer distance as the relative speed of the host vehicle 100 with respect to the target 200 increases. Therefore, in this example, the first collision condition CC1 may be a condition that the time required for the host vehicle 100 to reach the target 200 (target arrival time TTC) is equal to or less than the first time threshold TTC1 and longer than the second time threshold TTC2. In this case, the first time threshold TTC1 is set to a time longer than the second time threshold TTC2.

[0030] The vehicle driving assistance device 10 acquires the relative speed of the host vehicle 100 with respect to the target 200 based on the surrounding information IS. In addition, the vehicle driving assistance device 10 acquires the target arrival time TTC based on the target distance D and the relative speed of the host vehicle 100 with respect to the target 200.

[0031] Although the target 200 shown in FIG. 3 is a vehicle, the target 200 may also be a person, a two-wheeled vehicle, or a structure.

[0032] If the determination in step S205 is "Yes," the vehicle driving assistance device 10 proceeds to step S210, where it executes first driving force limiting control as one type of driving force limiting control. Next, the vehicle driving assistance device 10 proceeds to step S220.

[0033] The first driving force limiting control is a control that limits the additional driving force Pa (driving force added to the host vehicle 100) to a predetermined driving force Pg1 or less. In this example, the predetermined driving force Pg1 is set to a smaller value as the target distance D becomes shorter, and is particularly set to a value greater than zero. Therefore, as shown in FIG. 5, when the first collision condition CC1 is met at time t50, if the required driving force Pr is greater than the predetermined driving force Pg1, the additional driving force Pa decreases over time.

[0034] The first driving force limit control is stopped when the driver operates the brake pedal 43 or when the driver operates a shift lever (not shown) to decelerate the host vehicle 100.

[0035] On the other hand, if the determination in step S205 is "No," the vehicle driving assistance device 10 proceeds to step S215, where, if the first driving force limit control is being executed at this time, the first driving force limit control is stopped. Next, the vehicle driving assistance device 10 proceeds to step S220.

[0036] When the process proceeds to step S220, the vehicle driving assistance device 10 determines whether or not the second collision condition CC2 is met.

[0037] The second collision condition CC2 is a condition that, when a target 200 is present on the path of the host vehicle 100 ahead in the traveling direction of the host vehicle 100, there is a possibility that the host vehicle 100 will collide with the target 200. More specifically, the second collision condition CC2 is a condition that the target distance D is equal to or less than a second distance threshold D2 and greater than a third distance threshold D3. The second distance threshold D2 is set to a value greater than the third distance threshold D3. The third distance threshold D3 may be a constant value independent of the host vehicle speed V, but in this example, the third distance threshold D3 is set to a longer distance as the relative speed of the host vehicle 100 with respect to the target 200 increases. Therefore, in this example, the second collision condition CC2 may be a condition that the target arrival time TTC is equal to or less than a second time threshold TTC2 and greater than a third time threshold TTC3. The second time threshold TTC2 is set to a time longer than the third time threshold TTC3.

[0038] If the determination in step S220 is "Yes," the vehicle driving assistance device 10 proceeds to step S225, where it executes second driving force limiting control as one type of driving force limiting control. Next, the vehicle driving assistance device 10 proceeds to step S235.

[0039] The second driving force limit control is a control that limits the additional driving force Pa to equal to or less than a predetermined driving force Pg2, and in this example, the predetermined driving force Pg2 is set to zero. Therefore, in this example, the second driving force limit control is a control that stops the application of driving force to the host vehicle 100. Therefore, when the driving force limit control is executed, the vehicle driving assistance device 10 sets the additional driving force Pa to zero even if the required driving force Pr is greater than zero. That is, as shown in FIG. 5, when the second collision condition CC2 is met at time t51, the second driving force limit control is started and the additional driving force Pa becomes zero.

[0040] Furthermore, the second driving force limit control executed in step S225 is stopped when the driver operates the brake pedal 43 or when the driver operates the shift lever (not shown) to decelerate the vehicle 100.

[0041] On the other hand, if the determination in step S220 is "No," the vehicle driving assistance device 10 proceeds to step S230, where, if the second driving force limiting control is being executed, the second driving force limiting control is stopped. Next, the vehicle driving assistance device 10 proceeds to step S235.

[0042] When the process proceeds to step S235, the vehicle driving assistance device 10 determines whether or not the third collision condition CC3 is met.

[0043] The third collision condition CC3 is a condition that there is a possibility that the host vehicle 100 will collide with the target 200 when the target 200 is present ahead of the host vehicle 100 on the path of the host vehicle 100 in the traveling direction of the host vehicle 100, and more specifically, a condition that the target distance D is equal to or less than a third distance threshold D3. Note that the third collision condition CC3 may also be a condition that the target arrival time TTC is equal to or less than a third time threshold TTC3.

[0044] If the vehicle driving assistance device 10 determines "Yes" in step S235, the process proceeds to step S240, where the second driving force limit control and the automatic braking control are executed. That is, as shown in FIG. 5, when the third collision condition CC3 is satisfied at time t52, the second driving force limit control and the automatic braking control are started. The automatic braking control is a control that automatically brakes the host vehicle 100 to stop the host vehicle 100 before the host vehicle 100 collides with the target 200. Next, the vehicle driving assistance device 10 proceeds to step S245.

[0045] In this way, when there is a possibility that the host vehicle 100 will collide with the target 200 in front of the host vehicle 100, the vehicle driving assistance device 10 is configured to execute a second driving force limiting control that limits the additional driving force Pa, which is the driving force added to the host vehicle 100, to a predetermined driving force Pg2 or less, and to execute an automatic braking control that automatically brakes the host vehicle 100 to stop the host vehicle 100 before it collides with the target 200.

[0046] On the other hand, if the vehicle driving assistance device 10 determines "No" in step S235, the process proceeds directly to step S245.

[0047] When the process proceeds to step S245, the vehicle driving assistance device 10 determines whether or not a first stop condition CS1 is satisfied. The first stop condition CS1 is a condition that the host vehicle 100 is stopped by automatic braking control, and the stopped state of the host vehicle 100 continues for a predetermined time (predetermined stop duration Ts_th). However, the first stop condition CS1 may also be a condition that the host vehicle 100 is stopped by automatic braking control.

[0048] If the determination in step S245 is "No," the vehicle driving assistance device 10 proceeds directly to step S295 and temporarily ends the processing of this routine.

[0049] On the other hand, if the vehicle driving assistance device 10 determines "Yes" in step S245, the process proceeds to step S250 and executes the routine shown in Figure 3. Therefore, when the vehicle driving assistance device 10 proceeds to step S250, it starts the process from step S300 of the routine shown in Figure 3, proceeds to step S305, and stops the second driving force limit control and the automatic braking control. Next, the vehicle driving assistance device 10 proceeds to step S310 and executes the driving force return control. Therefore, the first stop condition CS1 is a condition for stopping the second driving force limit control and the automatic braking control, and is also a condition for executing the driving force return control.

[0050] The driving force return control is a control that increases the additional driving force Pa at a predetermined gradient θth toward the required driving force Pr. In other words, the driving force return control is a control that increases the additional driving force Pa at a predetermined increase rate Rth toward the required driving force Pr. The predetermined increase rate Rth is the amount by which the additional driving force Pa increases per unit time. Furthermore, when the target distance D is equal to or greater than the predetermined distance Dth, the predetermined gradient θth and the predetermined increase rate Rth are set to larger values ​​than when the target distance D is less than the predetermined distance Dth. In particular, in this example, the predetermined gradient θth and the predetermined increase rate Rth are set to larger values ​​as the target distance D becomes longer.

[0051] 5, if the target distance D is equal to or greater than the predetermined distance Dth when the first stop condition CS1 is satisfied at time t53, the additional driving force Pa increases along the line indicated by the symbol La, and reaches the required driving force Pr at time t54. On the other hand, if the target distance D is less than the predetermined distance Dth when the first stop condition CS1 is satisfied at time t53, the additional driving force Pa increases along the line indicated by the symbol Lb, and reaches the required driving force Pr at time t55, which is later than time t54. In other words, if the target distance D is equal to or greater than the predetermined distance Dth when the first stop condition CS1 is satisfied at time t53, the additional driving force Pa reaches the required driving force Pr in a shorter time than when the target distance D is shorter than the predetermined distance Dth.

[0052] In this way, the vehicle driving assistance device 10 is configured to stop the host vehicle 100 by executing the second driving force limit control and the automatic braking control, and when the first stop condition CS1 (predetermined stop condition) is satisfied, stop the second driving force limit control and the automatic braking control and apply the requested driving force Pr to the host vehicle 100. Furthermore, when the first stop condition CS1 (predetermined stop condition) is satisfied and a driving force greater than the predetermined driving force Pg2 is applied to the host vehicle 100, the vehicle driving assistance device 10 is configured to execute driving force return control that changes how the added driving force Pa is increased up to the requested driving force Pr in accordance with the target distance D (the relative relationship between the host vehicle 100 and the target 200).

[0053] Furthermore, if the driver accidentally operates the accelerator pedal 41 when the vehicle 100 is stopped by the automatic braking control, the additional driving force Pa does not suddenly increase to the required driving force Pr, but the additional driving force Pa gradually increases due to the driving force recovery control. This makes it possible to prevent the vehicle 100 from suddenly starting.

[0054] Furthermore, if the accelerator pedal operation amount AP is zero at the time the first stop condition CS1 is met, the additional driving force Pa will match the required driving force Pr at that time, so in effect, driving force recovery control will not be performed.

[0055] Next, the vehicle driving assistance device 10 proceeds to step S315 to determine whether the second stop condition CS2 is met.

[0056] The second stop condition CS2 is one of the following: the additional driving force Pa has reached the required driving force Pr; the driver has released the accelerator pedal 41; and the time elapsed since the start of the driving force return control (return duration Tr) has reached a predetermined return duration Tr_th.

[0057] If the determination in step S315 is "No," the vehicle driving assistance device 10 proceeds directly to step S395 and temporarily ends the processing of this routine.

[0058] On the other hand, if the vehicle driving assistance device 10 determines "Yes" in step S315, the process proceeds to step S320 and stops the driving force return control. Next, the vehicle driving assistance device 10 proceeds to step S395 and temporarily ends the processing of this routine. In this case, the vehicle driving assistance device 10 determines that the first stop condition CS1 is not satisfied in step S245 of the routine shown in FIG. 5. In the example shown in FIG. 5, the second stop condition CS2 is satisfied at time t54 or time t55, and the driving force return control is stopped.

[0059] The operation of the vehicle driving assistance device 10 is as described above.

[0060] When the subject vehicle 100 is stopped by automatic braking control and the requested driving force Pr is applied to the subject vehicle 100 when the automatic braking control is stopped, if the applied driving force Pa is increased in the same manner regardless of the target distance D, the acceleration of the subject vehicle 100 may be extremely small even though the target 200 is not near the subject vehicle 100, which may cause discomfort to the driver.

[0061] According to the vehicle driving assistance device 10, after the host vehicle 100 is stopped by automatic braking control, when the requested driving force Pr is applied to the host vehicle 100 when the automatic braking control is stopped, the driving force recovery control is executed and the way in which the added driving force Pa is increased up to the requested driving force Pr is changed according to the target distance D. This makes it possible to prevent the driver from feeling uncomfortable.

[0062] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. [Explanation of symbols]

[0063] 10... vehicle driving assistance device, 20... drive device, 30... braking device, 41... accelerator pedal, 42... accelerator pedal operation amount sensor, 50... vehicle speed detection device, 60... surrounding information detection device, 90... ECU, 100... host vehicle, 200... target

Claims

1. a control device that, when there is a possibility that the host vehicle will collide with a target object ahead of the host vehicle, executes a driving force limiting control that limits an additional driving force that is a driving force added to the host vehicle to a predetermined driving force or less, and also executes an automatic braking control that automatically brakes the host vehicle to stop the host vehicle before it collides with the target object, the control device is configured to stop the host vehicle by executing the driving force limit control and the automatic braking control, and when a predetermined stop condition is met, stop the driving force limit control and the automatic braking control, and apply to the host vehicle a requested driving force, which is a driving force corresponding to an operation amount of an accelerator pedal by a driver of the host vehicle. In a vehicle driving assistance device, The control device is configured to execute a driving force recovery control that changes a manner in which the additional driving force is increased up to the required driving force in accordance with a relative relationship between the host vehicle and the target object when the predetermined stop condition is satisfied and a driving force greater than the predetermined driving force is applied to the host vehicle. Vehicle driving assistance device.

2. The vehicle driving assistance device according to claim 1, the relative relationship is a distance between the host vehicle and the target; The control device is configured to change the manner in which the additional driving force is increased by increasing the gradient of the additional driving force when the distance is equal to or greater than a predetermined distance, compared to when the distance is less than the predetermined distance. Vehicle driving assistance device.

3. 3. The vehicle driving assistance device according to claim 1, the control device is configured to stop the driving force recovery control when the additional driving force reaches the required driving force. Vehicle driving assistance device.

Images