Driving assistance systems

Abstract

To provide a drive supporting device capable of suppressing a frequent change of a drive supporting level.SOLUTION: A drive supporting device comprises: an on-vehicle sensor that acquires target information about a target located around the own vehicle; and a processor capable of executing a drive supporting process that determines a drive supporting level, which is a degree of support for a driving operation, based on the target information, and that controls the own vehicle so that the drive supporting level of assistance is provided to a driver. When a predefined first condition is established as a condition for lowering the drive supporting level while the processor is executing a drive supporting process of a predetermined first level, the processor starts execution of a drive supporting process of a second level, which is lower than the first level, instead of the drive supporting process of the first level, and during a period in which a predefined second condition is established as a condition for determining that the first condition is likely to be established, the processor maintains the drive supporting level at the second level.SELECTED DRAWING: Figure 6

Description

[[Technical Field]]

[0001] The present invention relates to a driving assistance device that assists the driving operation of a host vehicle. [[Background Art]]

[0002] Driving assistance devices that assist the driving operation of a host vehicle have been proposed (see, for example, Patent Document 1 below). This driving assistance device (hereinafter referred to as "conventional device") has an automatic driving function that automatically advances the host vehicle. When the conventional device is executing automatic driving control, if there is a high possibility that another vehicle will enter (cut into) the space between the host vehicle and a preceding vehicle (the vehicle located immediately in front of the host vehicle), the conventional device controls the braking device (and / or the driving device) of the host vehicle such that the distance between the host vehicle and the preceding vehicle is increased. This makes it easier for said another vehicle to enter between the host vehicle and the preceding vehicle. [[Prior Art Literature]] [[Patent Literature]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Application Publication No. 2015-153153 [[Summary of the Invention]]

[0004] Meanwhile, as operation modes for automatic driving control, driving assistance devices that include, for example, a hands-on mode and a hands-off mode have been proposed. In either operation mode, the steering angle is automatically adjusted. In the hands-on mode, the driver is required to lightly touch the steering wheel. On the other hand, in the hands-off mode, taking the hands off the steering wheel (hands-off) is permitted. However, in the hands-off mode, if a predetermined condition (cancellation condition) is satisfied, the mode is forcibly changed from the hands-off mode to the hands-on mode. For example, the cancellation condition is satisfied when the distance between the host vehicle and another vehicle that has entered between the host vehicle and the preceding vehicle in the hands-off mode becomes less than a threshold value. In this way, the driving assistance device lowers the driving assistance level when the predetermined condition is satisfied.

[0005] In this scenario, where the cancellation condition is met, there is a high probability that the same cancellation condition will be met repeatedly within a short period of time. If the driver assistance system is configured to revert to the original level when the cancellation condition is no longer met, there is a risk that the driver assistance level will be changed frequently. Drivers may find the frequent changes in the driver assistance level (chattering) bothersome.

[0006] One of the objectives of the present invention is to provide a driver assistance device that can suppress frequent changes in the driver assistance level.

[0007] To solve the above problems, the driver assistance device (1) of the present invention assists in the driving operation of the vehicle. This driver assistance device includes an on-board sensor (20) that acquires target information relating to targets located around the vehicle (V), and a processor (10) that can execute a driver assistance process that determines a driver assistance level, which is the degree of assistance for the driving operation, based on the target information, and controls the vehicle so that the driver is provided with the assistance of that level. The processor is configured such that, while executing a predetermined first level of driver assistance processing, if a first condition (Xn1) predetermined as a condition for lowering the driver assistance level is met, it starts executing a second level of driver assistance processing that is lower than the first level instead of the first level of driver assistance processing, and maintains the driver assistance level at the second level during the period in which a second condition (Xn2) predetermined as a condition for determining that there is a high probability that the first condition will be met is met.

[0008] According to the driver assistance device of the present invention, after the driver assistance level is lowered from the first level to the second level, the state in which the second level of driver assistance is provided to the driver is maintained under circumstances where the first condition is likely to be met. Therefore, compared to the conventional device described above, the frequent changes in the driver assistance level are suppressed.

[0009] In a driving assistance device according to one aspect of the present invention, the processor determines that there is a high probability that another vehicle traveling in a second driving lane adjacent to the first driving lane in which the own vehicle is traveling will enter the first driving lane, and executes a vehicle-to-vehicle adjustment process to control the drive and / or braking devices of the own vehicle so that the other vehicle can enter the area directly in front of the own vehicle. The processor determines that the first condition has been met when, while the vehicle-to-vehicle adjustment process is being executed, the distance between the own vehicle and the other vehicle (Δd1) or the predicted time until the own vehicle and the other vehicle make contact (TTC1) falls below a threshold.

[0010] According to this system, the driver assistance level is lowered when there is a high probability that another vehicle will enter the area directly in front of the vehicle, and there is a high probability that the two vehicles will collide. This allows the driver to immediately begin taking action to avoid an emergency (for example, when the two vehicles come very close together).

[0011] In another aspect of the present invention, the driver assistance device determines that the second condition is met when the vehicle is traveling in a lane merging section.

[0012] In merging sections, there is a possibility that multiple other vehicles will sequentially enter the area directly in front of the vehicle, making the first condition likely to be met relatively frequently. According to the present invention, the driver assistance level is maintained at the second level while driving through such a section. In other words, frequent changes in the driver assistance level are suppressed.

[0013] In another aspect of the present invention, the driver assistance device determines that the second condition is met when there is a high probability that another vehicle, different from the other vehicle, will enter the area.

[0014] A scenario is envisioned where, after the driver assistance level is lowered triggered by another vehicle (first other vehicle) approaching the area directly in front of the vehicle, another other vehicle (second other vehicle) attempts to enter the same area. In this case, even if the first condition is not met at that moment, there is a high probability that the first condition will be met later for the second other vehicle. According to the driver assistance device of this embodiment, the driver assistance level is maintained at the second level in this scenario. In other words, frequent changes in the driver assistance level are suppressed.

[0015] In another aspect of the present invention, the driver assistance device measures the elapsed time (Δt) from a first time point in time when it is determined that the first condition has been met, and if it is no longer possible to detect the other vehicle after the first time point, it determines that the second condition has been met under the condition that the elapsed time is less than a threshold (Δtth).

[0016] For example, at night or in rainy weather, it may be difficult for the vehicle's sensors to accurately recognize other vehicles. In this case, the driver assistance level is maintained at the second level when the elapsed time is below a threshold (for example, the average time it takes for a typical vehicle to change lanes). In other words, frequent changes in the driver assistance level are suppressed. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 is a block diagram of a driver assistance device according to one embodiment of the present invention. [Figure 2] Figure 2 is a plan view of the highway merging section and its surrounding area. [Figure 3] Figure 3 is a plan view showing the sections of the expressway other than the merging sections. [Figure 4] Figure 4 is a flowchart of the program that sets the flag FH. [Figure 5] Figure 5 is a flowchart of the program that sets the flag FXn. [Figure 6]FIG. 6 is a flowchart of a program for determining whether a specific condition is satisfied. MODE FOR CARRYING OUT THE INVENTION

[0018] (Outline) A driving assistance device 1 according to one embodiment of the present invention is mounted on a vehicle V (hereinafter referred to as "the own vehicle"). The driving assistance device 1 assists a driving operation performed by a driver. For example, the driving assistance device 1 has a function (autonomous driving function) of executing autonomous driving control that controls the own vehicle so that the own vehicle travels automatically. The driving assistance device 1 changes the degree of assistance for driving operation (driving assistance level) according to the situation.

[0019] (Specific Configuration) As shown in FIG. 1, the driving assistance device 1 includes a driving assistance ECU 10, an on-board sensor 20, a drive device 30, a brake device 40, and a steering device 50.

[0020] The driving assistance ECU 10 includes a CPU 10a, a ROM 10b, a RAM 10c, a timer 10d, and the like. The driving assistance ECU 10 is connected to other ECUs (for example, ECUs of the drive device 30, the brake device 40, and the steering device 50 described later) via a CAN.

[0021] The on-board sensor 20 includes a radar 21, a sonar 22, and a camera 23 serving as surrounding sensors that acquire information related to targets existing around the own vehicle (target information).

[0022] The radar 21 includes a transmission / reception unit and a signal processing unit. The transmission / reception unit radiates radio waves in the millimeter wave band (hereinafter referred to as "millimeter waves") forward of the own vehicle, and receives millimeter waves (reflected waves) reflected by a three-dimensional object located within the radiation range. The signal processing unit recognizes the distance between the own vehicle and the three-dimensional object, the relative position (direction) of the three-dimensional object with respect to the own vehicle, and the like based on the time from when the transmission / reception unit radiates the millimeter wave to when it receives the reflected wave, the phase difference between the transmitted millimeter wave and the received reflected wave, the attenuation degree of the reflected wave, and the like, and transmits the recognition result to the driving assistance ECU 10.

[0023] The sonar 22 intermittently emits ultrasonic waves to the area surrounding the own vehicle and receives the ultrasonic waves (reflected waves) reflected by a three-dimensional object. The sonar 22 recognizes the distance between the own vehicle and the three-dimensional object, the relative position (direction) of the three-dimensional object with respect to the own vehicle, and the like based on the time from transmitting the ultrasonic waves to receiving the reflected waves, and transmits the recognition result to the driving support ECU 10.

[0024] The camera 23 includes an imaging device and an image analysis device. The imaging device incorporates, for example, a CCD. The imaging device is installed at the front portion of the own vehicle. The imaging device captures the foreground of the own vehicle at a predetermined frame rate to acquire image data. The image analysis device analyzes the image data to recognize targets and signs existing around the own vehicle from the image. For example, the image analysis device recognizes other vehicles, lane marks (marking lines that divide travel lanes, curbs, medians, etc.) and the like, and transmits the recognition result to the driving support ECU 10. Note that the image analysis device can identify a plurality of other vehicles based on the shape and color of each other vehicle, the number written on the license plate, and the like.

[0025] Further, the in-vehicle sensor 20 includes a vehicle speed sensor 24 that detects the vehicle speed of the own vehicle. Furthermore, the in-vehicle sensor 20 includes a switch 25. The switch 25 includes a push-button type start switch 25a for a driver to request the driving support device 1 to start an automatic driving process described later. Each time the start switch 25a is pressed, the on-off state of the switch 25a is alternately switched.

[0026] Furthermore, the in-vehicle sensor 20 includes a navigation system 26. In addition, the in-vehicle sensor 20 includes a sensor (not shown) that detects the depression depth of a brake pedal, a sensor (not shown) that detects whether a driver is touching a steering wheel, and the like.

[0027] The drive unit 30 applies driving force to the drive wheels. The drive unit 30 includes an engine ECU, an internal combustion engine, a transmission, and a power transmission mechanism that transmits driving force to the wheels. The engine ECU controls the throttle valve so that the output of the internal combustion engine matches a target value. The engine ECU also controls the transmission so that the shift position of the transmission in the vehicle matches a target position.

[0028] Furthermore, if the vehicle to which the driver assistance system 1 is applied is a hybrid electric vehicle (HEV), the engine ECU can control the vehicle's driving force generated by either the internal combustion engine or the electric motor, or both, as the vehicle's power source. Also, if the vehicle to which the driver assistance system 1 is applied is an electric electric vehicle (BEV), an electric motor ECU is used instead of the engine ECU to control the vehicle's driving force generated by the electric motor, which is the vehicle's power source.

[0029] The braking system 40 applies braking force to the wheels (brake discs). The braking system 40 includes a brake ECU, brake calipers, etc. The brake ECU controls the brake calipers so that the braking force applied to the wheels matches a target value.

[0030] The steering system 50 controls the steering angle of the steering wheels (left front wheel and right front wheel). The steering system 50 includes a steering ECU, a steering mechanism, and the like. The steering system 50 further includes actuators that drive the steering mechanism to change the steering angle. The steering ECU controls the actuators so that the steering angle matches a target value.

[0031] (Automated Driving Function) When the driver assistance ECU 10 detects that the start switch 25a has transitioned to the ON state, it starts the automated driving process (driver assistance process). That is, the driver assistance ECU 10 controls the drive unit 30, braking unit 40, and steering unit 50 (hereinafter referred to as "drive unit, etc.") so that the vehicle automatically moves along the currently running lane (or a pre-set route). The driver assistance device 1 has hands-off mode and hands-on mode as operating modes MD of the automated driving function, similar to the conventional device described above. In hands-on mode, when the driver assistance ECU 10 detects that the driver is not touching the steering wheel, it controls the notification device so that a predetermined warning is issued.

[0032] The driver assistance ECU 10 uses the flags FXn (n=1,2,···,max) and FH to switch the operating mode MD during the autonomous driving process.

[0033] Flag FXn is associated with each condition Xn1 used to determine whether it is preferable to set the operating mode MD to hands-on mode. The driver assistance ECU 10 sets flag FXn to "1" if condition Xn1 is true. On the other hand, the driver assistance ECU 10 sets flag FXn to "0" if condition Xn1 is false. However, after the driver assistance ECU 10 sets flag FXn(n=a,b,c,...) to "1" triggered by the fulfillment of a specific condition Xn1(n=a,b,c,...), even if that specific condition Xn1 becomes false, it maintains flag FXn to "1" during the period when condition Xn2, which determines that there is a high probability that that specific condition Xn1 will be true, is true. Subsequently, the driver assistance ECU 10 sets flag FXn to "0" if both condition Xn1 and condition Xn2 are false. Thus, the conditions for changing a specific flag FXn (n=a,b,c,···) from "1" to "0" are stricter than the conditions for changing it from "0" to "1".

[0034] Flag FH indicates whether hands-off driving is permitted or not. When flag FH is "0", hands-off driving is prohibited, and when flag FH is "1", hands-off driving is permitted. The driver assistance ECU 10 sets flag FH to "0" if at least one flag FXn is "1" (the logical OR of all flags FXn is "1"). In other words, the driver assistance ECU 10 prohibits hands-off driving. That is, the driver assistance ECU 10 sets the operating mode MD to hands-on mode. On the other hand, the driver assistance ECU 10 sets flag FH to "1" if all flags FXn are "0" (the logical OR of all flags FXn is "0"). That is, the driver assistance ECU 10 permits hands-off driving. That is, the driver assistance ECU 10 sets the operating mode MD to hands-off mode.

[0035] For example, when the vehicle is traveling on an ordinary road or on a highway at a relatively high speed (e.g., 40 km / h or more), the driver assistance ECU 10 determines that condition X11 is met and sets flag FX1 to "1". On the other hand, when the vehicle is traveling on a highway at a relatively low speed (less than 40 km / h), the driver assistance ECU 10 determines that condition X11 is not met and sets flag FX1 to "0". In this embodiment, service areas (rest stops) on highways are included in ordinary roads.

[0036] Furthermore, for example, if the distance Δd0 between the vehicle and the preceding vehicle (vehicle V2) is less than the threshold Δd0th (or if the predicted time TTC0 until the vehicle collides with vehicle V2 is less than the threshold TTC0th), the driver assistance ECU 10 determines that condition X21 is met and sets flag FX2 to "1". On the other hand, if the distance Δd0 is greater than or equal to the threshold Δd0th (or if the predicted time TTC0 is greater than or equal to the threshold ΔTTC0th), the driver assistance ECU 10 determines that condition X21 is not met and sets flag FX2 to "0". In this embodiment, "preceding vehicle" (vehicle V2) means a vehicle traveling in the same lane L0 as the vehicle departing, and that is traveling directly in front of the vehicle departing. A vehicle that straddles the lane line separating lane L0 and the adjacent lane L1 is not included in "preceding vehicle".

[0037] Furthermore, the driver assistance ECU 10 determines that condition X31 is met and sets flag FX3 to "1" if there is a high risk of contact between the vehicle and another vehicle (vehicle V1) traveling in lane L1. Specifically, the driver assistance ECU 10 monitors the behavior of vehicle V1 traveling in lane L1 adjacent to the lane L0 in which the vehicle is traveling. For example, as shown in Figure 2, the driver assistance ECU 10 determines that there is a high probability that vehicle V1 will enter the area R0 directly in front of the vehicle if vehicle V1, located in a predetermined area in lane L1 and diagonally in front of the vehicle, is flashing its turn signal on the lane L0 side. Area R0 is a rectangular area extending forward from the front end of the vehicle. The width of area R0 is the same as the width of lane L0. The length of area R0 is the same as the distance between the rear end of vehicle V2 and the front end of the vehicle. If vehicle V2 is not present, the length of region R0 is approximately twice the total length of the vehicle itself. The driver assistance ECU 10 also determines that if vehicle V1 is straddling the lane marking that separates lane L0 and lane L1 in front of the vehicle itself, there is a high probability that vehicle V1 will enter region R0. If the driver assistance ECU 10 determines that there is a high probability that vehicle V1 will enter region R0, it executes a distance adjustment process that controls the vehicle's drive unit 30 and / or braking unit 40 so that the distance Δd1 (distance in the longitudinal direction) between the vehicle itself and vehicle V1 is greater than or equal to the threshold Δd1th (>Δd0th) (or the predicted time TTC1 is greater than or equal to the threshold TTC1th (>TTC0th)). The driver assistance ECU 10 encourages vehicle V1 to enter region R0 by executing the distance adjustment process, but for example, if vehicle V1 decelerates suddenly, the distance Δd1 may temporarily fall below the threshold Δd1th. In this case, the driver assistance ECU 10 determines that there is a high risk of contact between vehicle V1 and the vehicle in question. In this case, the driver assistance ECU 10 determines that condition X31 (the first condition of the present invention) has been met and sets flag FX3 to "1". That is, hands-off driving is prohibited. This allows the driver to avoid contact between the vehicle in question and vehicle V1 by immediately operating the steering wheel (steering override) if, for example, vehicle V1 slows down further and approaches the vehicle in question.

[0038] The driver assistance ECU 10 continues to monitor the behavior of vehicle V1 after setting flag FX3 to "1". Here, even if condition X31 is temporarily not met after it has been met, condition X31 may be met again immediately afterward.

[0039] For example, even if, after condition X31 is met (before vehicle V1 completes its entry into region R0), the distance Δd1 temporarily increases to exceed the threshold Δd1th, causing condition X31 to become unmet, it is possible that later (before vehicle V1 completes its entry into region R0), the distance Δd1 may decrease again to fall below the threshold Δd1th, thus making condition X31 met again.

[0040] Furthermore, if your vehicle is traveling in the merging section M between driving lane L1 and driving lane L0, there is a possibility that another vehicle V3 may enter area R0 from area R1, following vehicle V1. Also, as shown in Figure 3, while traveling in a section of the highway other than the merging section, there is a possibility that vehicle V3 may enter area R0, following vehicle V1 (a vehicle that has completed a lane change (vehicle V2 in the same figure)). In these cases, even if condition X31 is not met for vehicle V1, there is a high probability that condition X31 will be met for vehicle V3.

[0041] Therefore, the driver assistance ECU 10 maintains flag FX3 at "1" during the period in which condition X32, which determines that there is a high probability that condition X31 is met, is met, as described below.

[0042] Specifically, the driver assistance ECU 10 determines that condition X32 is met when vehicle V1 is in the process of entering area R0. Furthermore, the driver assistance ECU 10 determines that condition X32 is met when the vehicle is traveling through a merging section M. Additionally, the driver assistance ECU 10 determines that condition X32 is met regardless of distance Δd1 if the vehicle is traveling in a section other than a merging section M (a non-merging section) and there is a vehicle V3 in area R1 with its turn signal on the L0 side flashing.

[0043] On the other hand, the driver assistance ECU 10 recognizes that vehicle V1 has completed its entry into area R0, and determines that condition X32 is not met if its own vehicle is not traveling in the merging section M and there is no vehicle V3 attempting to enter area R0.

[0044] Furthermore, under conditions where the image recognition accuracy of camera 23 is reduced (such as rain or nighttime), the driver assistance ECU 10 may have difficulty recognizing that vehicle V1 has completed its entry into region R0. In this case, if the driver assistance ECU 10 loses track of vehicle V1 after setting flag FX3 to "1" at time t0, it will consider that vehicle V1 has completed its entry into region R0 at time t1, when the elapsed time Δt from time t0 reaches the threshold Δtth.

[0045] Furthermore, if the brake pedal is depressed, the driver assistance ECU 10 determines that condition X41 is met and sets flag FX4 to "1". On the other hand, if the brake pedal is released, the driver assistance ECU 10 determines that condition X41 is not met and sets flag FX3 to "0". However, if the brake pedal is depressed while the driver assistance ECU 10 is performing distance adjustment processing, it determines that condition X31 is met in addition to condition X41. That is, the driver assistance ECU 10 sets flag FX4 to "1" and sets flag FX3 to "1" regardless of the distance Δd1 (even if the distance Δd1 is greater than or equal to the threshold Δd1th).

[0046] Next, referring to Figures 4 and 5, we will describe the programs PR1, PR2, and PR3 executed by the CPU 10a (hereinafter simply referred to as "CPU") to realize the function of switching the operating mode MD according to the situation. When the CPU detects that the start switch 25a has transitioned to the ON state, it starts executing programs PR1 to PR3. When the CPU detects that the switch 25a is in the OFF state, it interrupts the execution of programs PR1 to PR3.

[0047] (Program PR1) The CPU starts executing Program PR1 (Figure 4) from step 100 and proceeds to step 101.

[0048] In step 101, the CPU calculates the logical OR of flags FX1 through FXmax and determines whether the OR is "0". The CPU executes program PR1 and simultaneously executes programs PR2 and PR3 (described later) (parallel processing) to set flags FX1 through FXmax to "1" or "0", respectively. If the CPU determines that the OR is "0" (101: Yes), it proceeds to step 102. On the other hand, if the CPU does not determine that the OR is "0" (101: No), it proceeds to step 103.

[0049] In step 102, the CPU sets the flag FH to "1" (allowing hands-off) and returns processing to step 101. On the other hand, in step 103, the CPU sets the flag FH to "0" (disabling hands-off) and returns processing to step 101.

[0050] (Program PR2) Program PR2 sequentially selects flags FXn (n=1,2,3,...,max) as targets for processing, and includes a step that changes flag FXn from "0" to "1" if condition Xn1 is met. Note that the step of changing flag FXn from "1" to "0" is not included in Program PR2, but is included in Program PR3, which will be described later.

[0051] The CPU starts executing program PR2 (Figure 5(A)) from step 200 and proceeds to step 201.

[0052] In step 201, the CPU sets index n to "1" to specify (select) the flag FXn to be processed. Next, the CPU proceeds to step 202.

[0053] In step 202, the CPU determines whether the flag FXn is "0". If the CPU determines that the flag FXn is "0" (202: Yes), it proceeds to step 203. On the other hand, if the CPU does not determine that the flag FXn is "0" (202: No), it proceeds to step 205, which will be described later.

[0054] In step 203, the CPU determines whether condition Xn1 is true. If the CPU determines that condition Xn1 is true (203: Yes), it proceeds to step 204. On the other hand, if the CPU does not determine that condition Xn1 is true (203: No), it proceeds to step 205.

[0055] In step 204, the CPU sets the flag FXn to "1". Then, the CPU proceeds to step 205.

[0056] In step 205, the CPU determines whether index n is less than the maximum value max. If the CPU determines that index n is less than the maximum value max (205: Yes), it proceeds to step 206. On the other hand, if the CPU does not determine that index n is less than the maximum value max (205: No), it returns to step 201.

[0057] In step 206, the CPU increments index n. Then, the CPU returns to step 202.

[0058] (Program PR3) Program PR3 sequentially selects flags FXn (n=1,2,3,...,max) as targets for processing, and includes a process (step) that changes flag FXn from "1" to "0" if condition Xn1 (condition Xn1 and condition Xn2 for a particular flag FXn) is not met.

[0059] The CPU starts executing program PR3 (Figure 5(B)) from step 300 and proceeds to step 301.

[0060] In step 301, the CPU sets index n to "1" to specify (select) the flag FXn to be processed. Next, the CPU proceeds to step 302.

[0061] In step 302, the CPU determines whether the flag FXn is "1". If the CPU determines that the flag FXn is "1" (302: Yes), it proceeds to step 303. On the other hand, if the CPU does not determine that the flag FXn is "1" (302: No), it proceeds to step 307, which will be described later.

[0062] In step 303, the CPU determines whether condition Xn1 is false or not. If the CPU determines that condition Xn1 is false (303: Yes), it proceeds to step 304. On the other hand, if the CPU does not determine that condition Xn1 is false (303: No), it proceeds to step 306, which will be described later.

[0063] In step 304, the CPU determines whether it has selected a specific flag FXn to be processed. That is, the CPU determines whether index n corresponds to one of the specific values ​​[a, b, c, ...]. If the CPU determines that it has selected a specific flag FXn to be processed (304: Yes), it proceeds to step 305. On the other hand, if the CPU does not determine that it has selected a specific flag FXn to be processed (304: No), it proceeds to step 306.

[0064] In step 305, the CPU determines whether condition Xn2 is true. If the CPU determines that condition Xn2 is true (305: Yes), it proceeds to step 307. In other words, in this case, the flag FXn is not changed. That is, the CPU maintains the state where hands-off driving is prohibited (a state set to hands-on mode, which has a lower level of driving assistance compared to hands-off mode). On the other hand, if the CPU does not determine that condition Xn2 is true (305: No), it proceeds to step 306.

[0065] In step 306, the CPU sets the flag FXn to "0". Then, the CPU proceeds to step 307.

[0066] In step 307, the CPU determines whether index n is less than the maximum value max. If the CPU determines that index n is less than the maximum value max (307: Yes), it proceeds to step 308. On the other hand, if the CPU does not determine that index n is less than the maximum value max (307: No), it returns to step 301.

[0067] In step 308, the CPU increments index n. Then, the CPU returns to step 302.

[0068] Next, we will explain a specific example of the process for determining whether conditions Xn1 and Xn2 are met. When the brake pedal is not pressed, the CPU executes program PR4 (Figure 6(A)) to determine whether condition X31 is met. The CPU also executes program PR5 (Figure 6(B)) to determine whether condition X32 is met.

[0069] (Program PR4) The CPU starts executing Program PR4 from step 400 and proceeds to step 401.

[0070] In step 401, the CPU determines whether or not there is a vehicle V1 that is likely to enter region R0. If the CPU determines that vehicle V1 is present (401: Yes), it starts the vehicle distance adjustment process and proceeds to step 402. On the other hand, if the CPU does not determine that vehicle V1 is present (401: No), it proceeds to step 404, which will be described later.

[0071] In step 402, the CPU determines whether the distance Δd1 (predicted time TTC1) is less than the threshold Δd1th (threshold TTC1th). If the CPU determines that the distance Δd1 (predicted time TTC1) is less than the threshold Δd1th (threshold TTC1th) (402; Yes), it proceeds to step 403. On the other hand, if the CPU does not determine that the distance Δd1 (predicted time TTC1) is less than the threshold Δd1th (threshold TTC1th) (402; No), it proceeds to step 404.

[0072] In step 403, the CPU determines that condition X31 is met. In this case, the CPU starts measuring the elapsed time Δt. Then, in step 405, the CPU terminates the execution of program PR4.

[0073] Furthermore, in step 404, the CPU determines that condition X31 is not met. Next, the CPU proceeds to step 405, in which step 405, the execution of program PR4 is terminated.

[0074] (Program PR5) The CPU starts executing Program PR5 (Figure 6(B)) from step 500 and proceeds to step 501.

[0075] In step 501, the CPU determines whether vehicle V1 has entered area R0 (whether it has detected that the interrupt has been completed). If the CPU determines that vehicle V1 has entered area R0 (501: Yes), it proceeds to step 504, which will be described later. On the other hand, if the CPU does not determine that vehicle V1 has entered area R0 (either because vehicle V1 is in the process of entering area R0 or because it has lost track of vehicle V1 (501: No)), it proceeds to step 502.

[0076] In step 502, the CPU determines whether it has lost track of vehicle V1 (the vehicle related to the factor that caused flag FX3 to be set to "1"). If the CPU determines that it has lost track of vehicle V1 (502: Yes), it proceeds to step 503. On the other hand, if the CPU does not determine that it has lost track of vehicle V1 (502: No), it proceeds to step 506.

[0077] In step 503, the CPU determines whether the elapsed time Δt is greater than or equal to the threshold Δtth. If the CPU determines that the elapsed time Δt is greater than or equal to the threshold Δtth (503: Yes), it proceeds to step 504, which will be described later. On the other hand, if the CPU does not determine that the elapsed time Δt is greater than or equal to the threshold Δtth (503: No), it proceeds to step 506.

[0078] In step 504, the CPU determines whether the vehicle is traveling in merging section M. If the CPU determines that the vehicle is traveling in merging section M (504: Yes), it proceeds to step 506. On the other hand, if the CPU does not determine that the vehicle is traveling in merging section M (504: No), it proceeds to step 505.

[0079] In step 505, the CPU determines whether there is a vehicle V3 that is highly likely to enter region R0. If the CPU determines that vehicle V3 exists (505: Yes), it proceeds to step 506. On the other hand, if the CPU does not determine that vehicle V3 exists (505: No), it proceeds to step 507.

[0080] In step 506, the CPU determines that condition X32 is true. In step 507, the CPU determines that condition X32 is false. Finally, in step 508, the CPU terminates the execution of program PR5.

[0081] (Effect) According to the driver assistance device 1, after the operating mode MD (driver assistance level) is changed from hands-off mode (first level) to hands-on mode (second level), the operating mode MD is maintained in hands-on mode when there is a high probability that condition Xn1 (first condition) is met (when condition Xn2 is met). Therefore, compared to the conventional device described above, the frequent changes in the driver assistance level are suppressed. [Explanation of Symbols]

[0082] 1…Driver assistance system, 10…Driver assistance ECU, 20…On-board sensor, 30…Drive system, 40…Braking system, 50…Steering system

Claims

1. A driver assistance device that assists in the operation of the vehicle, An on-board sensor that acquires object information about objects located around the vehicle, A processor capable of executing a driving assistance process that determines a driving assistance level, which is the degree of assistance for the driving operation, based on the aforementioned target information, and controls the vehicle so that the driver is provided with the assistance of that level. Equipped with, The processor is configured such that, while executing a predetermined first level of driver assistance processing, if a first condition predetermined as a condition for lowering the driver assistance level is met, it will start executing a second level of driver assistance processing that is lower than the first level, instead of the first level of driver assistance processing, and will maintain the driver assistance level at the second level during the period in which a second condition predetermined as a condition for determining that there is a high probability that the first condition will be met is met. A driver assistance device configured to perform a distance adjustment process that controls the drive and / or braking systems of the vehicle in order to allow the other vehicle to enter the area directly in front of the vehicle, when it is determined that there is a high probability that another vehicle traveling in a second driving lane adjacent to the first driving lane in which the vehicle is traveling will enter the first driving lane, and to determine that the first condition has been met when the distance between the vehicle and the other vehicle or the predicted time until the vehicle and the other vehicle make contact falls below a threshold while the distance adjustment process is being performed.

2. In the driving support device according to claim 1, The processor determines that the second condition is met when the vehicle is traveling in a lane merging section. A driver assistance system configured in such a way.

3. In the driving support device according to claim 1, The aforementioned processor is a driver assistance device configured to determine that the second condition is met when there is a high probability that another vehicle, different from the aforementioned other vehicle, will enter the area.

4. In the driving support device according to claim 1, The driver assistance device is configured such that the processor measures the elapsed time from a first point in time when it is determined that the first condition has been met, and if it is no longer able to detect the other vehicle after the first point in time, it determines that the second condition has been met if the elapsed time is less than a threshold.

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