Driving support control device for vehicle

Abstract

To provide a driving support control device for a vehicle capable of performing braking in consideration of a following vehicle during driving by cruise control.SOLUTION: A driving support control device for a vehicle that automatically adjusts a vehicle speed by controlling a driving unit and a braking unit of the vehicle includes a driving support control unit that has a first driving support mode for controlling the host vehicle so as to maintain a vehicle speed set by a driver and a second driving support mode for performing acceleration according to an accelerator operation by the driver when there is the accelerator operation by the driver, and a lane change detection unit that detects that the host vehicle has changed a lane and has gone ahead of another vehicle. The driving assist controller may be configured to, after the lane change detector detects that the vehicle has gotten out in front of the other vehicle, execute a deceleration relaxation control to make deceleration in the first driving assist mode more gradual than usual.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a driving assistance control device for a vehicle. [Background technology]

[0002] In recent years, vehicles equipped with a function (cruise control) that assists driving operations have become widespread. Cruise control mainly automatically controls the acceleration and deceleration of a vehicle and has several driving modes. For example, the driving modes include a mode (constant speed driving mode) in which the vehicle accelerates or decelerates to maintain a vehicle speed set by the driver (hereinafter referred to as the set speed), a mode (accelerator priority mode) in which the vehicle accelerates according to accelerator operation when the driver steps on the accelerator during cruise control, and a mode (following mode) in which the vehicle accelerates or decelerates to maintain a constant distance from another vehicle ahead (hereinafter referred to as the leading vehicle) when the distance between the vehicle and the leading vehicle becomes close.

[0003] Patent Document 1 discloses a vehicle equipped with a following suppression function that suppresses the distance between the host vehicle and a preceding vehicle from becoming too close. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-24337 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, there are cases where a vehicle using cruise control on a highway or the like catches up with a vehicle ahead, changes lanes, passes the vehicle ahead, and then returns to the original lane. In this case, the cruise control's driving mode switches to accelerator priority mode when the driver depresses the accelerator to pass, and switches to constant speed cruising mode when the driver returns to the original lane and releases the accelerator. In such a situation, when switching from accelerator priority mode to constant speed cruising mode, the vehicle speed is often higher than the set speed, and the vehicle decelerates to return to the set speed.

[0006] However, immediately after overtaking, there is another vehicle (following vehicle) behind the own vehicle, and if the own vehicle suddenly decelerates to reach the set vehicle speed, the driver of the following vehicle may feel uncomfortable without the driver intending it. Also, it is possible that the following vehicle will also decelerate due to the deceleration of the own vehicle.

[0007] Patent Document 1 controls the distance between the vehicle and a preceding vehicle, but does not disclose the relationship with a following vehicle.

[0008] Therefore, an object of the present disclosure is to provide a driving assistance control device for a vehicle that can perform braking taking into consideration following vehicles when driving using cruise control. [Means for solving the problem]

[0009] The present disclosure has been made to solve at least some of the above-mentioned problems, and can be realized as the following aspects or application examples.

[0010] The driving assistance control device of a vehicle according to this application example is a driving assistance control device for a vehicle that automatically adjusts vehicle speed by controlling the drive and braking units of the vehicle, and has a driving assistance control unit that has a first driving assistance mode that controls the vehicle to maintain a vehicle speed set by the driver, and a second driving assistance mode that accelerates the vehicle in accordance with accelerator operation when the driver operates the accelerator, and a lane change detection unit that detects when the vehicle has changed lanes and moved in front of another vehicle, and is characterized in that the driving assistance control unit is capable of executing deceleration mitigation control that makes deceleration in the first driving assistance mode more gradual than usual after detecting that the vehicle has moved in front of the other vehicle using the lane change detection unit.

[0011] In other words, according to this application example, when the host vehicle changes lanes and moves ahead of another vehicle, the deceleration rate in the first driving assistance mode is made gentler than normal, thereby alleviating discomfort felt by the driver of the following vehicle. Furthermore, chain braking of the following vehicles can be suppressed, thereby mitigating the occurrence of traffic congestion. In this way, this application example allows braking that takes following vehicles into consideration when driving using cruise control. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing the configuration of a vehicle equipped with a driving assistance control device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a schematic diagram illustrating an example of a vehicle overtaking another vehicle according to the present embodiment. [Figure 3] 4 is a flowchart showing a driving assistance control routine according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the content described below, and can be implemented with any modifications within the scope of the gist of the present invention. Furthermore, the drawings used to explain the embodiments are all schematic representations of components, and may be partially emphasized, enlarged, reduced, or omitted to facilitate understanding, and may not accurately represent the scale, shape, etc. of the components.

[0014] 1 is a schematic diagram showing a host vehicle 1 equipped with a driving assistance control device according to this embodiment. The host vehicle 1 is a commercial vehicle such as a bus or truck. As shown in FIG. 1, the host vehicle 1 includes a drive unit 10 that is a drive source for traveling, a braking unit 11 that brakes the host vehicle, and an ECU 12 that controls the host vehicle 1.

[0015] The drive unit 10 is an engine. Although not shown, the output shaft of the engine is connected to left and right drive wheels via a power transmission unit consisting of a transmission and a differential, and a drive shaft. The drive force generated by the drive unit 10 is transmitted to the drive wheels, enabling the host vehicle 1 to travel. In this embodiment, the left and right rear wheels 20RR, 20RL are drive wheels, and the front wheels 20FR, 20FL are driven wheels and steered wheels.

[0016] Specifically, the braking unit 11 is made up of drum brakes 21FR, 21FL, 21RR, and 21RL provided on the wheels 20FR, 20FL, 20RR, and 20RL. The type of brake is not limited to drum brakes, and may be, for example, disc brakes. Furthermore, the braking unit 11 is not limited to friction brakes such as drum brakes and disc brakes, and may include auxiliary brakes such as an engine compression release brake, a retarder, an exhaust brake, and a regenerative brake.

[0017] The ECU (Electronic Control Unit) 12 is a computer including a central processing unit (CPU), a main memory device (ROM, RAM, etc.) for storing control programs, control maps, etc., an input / output device, a timer counter, etc. The ECU 12 is communicatively connected to various devices and other control units mounted on the vehicle 1 via a CAN (Control Area Network), which is an in-vehicle communication network.

[0018] For example, the ECU 12 of this embodiment is connected to various sensors and switches, such as an accelerator sensor 23 that detects the amount of operation of the accelerator pedal 22, a brake switch 25 that detects the depression of the brake pedal 24, a direction indicator sensor 26 that detects the operation of a turn signal, a cruise control switch 27 that starts and stops cruise control and changes the set vehicle speed, a vehicle speed sensor 28 that detects the speed of the vehicle 1, and object detection sensors 29F, 29R, 29L, and 29B (collectively referred to as object detection sensors 29) provided on the left, right, front, and rear of the vehicle 1.

[0019] The object detection sensors 29 are, for example, millimeter-wave radars, with object detection sensor 29F at the front of the vehicle detecting objects in front of the vehicle, object detection sensor 29B at the rear of the vehicle detecting objects behind the vehicle, object detection sensor 29L at the left of the vehicle detecting objects to the left of the vehicle, and object detection sensor 29R at the right of the vehicle detecting objects to the right of the vehicle. The objects to be detected are mainly other vehicles (including four-wheeled vehicles and two-wheeled vehicles), and not only can they detect the presence or absence of an object, but they can also detect the distance and direction of the detected object relative to the vehicle. Note that the object detection sensors are not limited to millimeter-wave radars as long as they can detect objects in each direction, and may be, for example, cameras that capture images, or a combination of a camera and radar.

[0020] The ECU 12 of this embodiment includes a lane change detection unit 12a and a driving assistance control unit 12b.

[0021] The lane change detection unit 12a has a function of detecting that the host vehicle 1 has changed lanes and is ahead of another vehicle. Specifically, the lane change detection unit 12a detects that the host vehicle 1 has changed lanes based on direction indication information detected by the direction indication sensor 26. The lane change detection unit 12a then detects that the host vehicle 1 has moved ahead of another vehicle based on object information detected by the object detection sensor 29. For example, the lane change detection unit 12a detects that the host vehicle 1 has moved ahead of another vehicle by detecting a following vehicle that is at a following vehicle distance Dr that is less than a predetermined following vehicle distance threshold D2 using the object detection sensor 29R at the rear of the vehicle after the lane change.

[0022] The driving assistance control unit 12b has a function of performing so-called cruise control to assist the driving operation of the vehicle 1. The cruise control performed by the driving assistance control unit 12b in this embodiment controls the drive unit 10 and the brake unit 11 to automatically control the acceleration and deceleration of the vehicle, and has three driving modes.

[0023] The first driving assistance mode is a so-called constant speed mode in which the host vehicle 1 is controlled to maintain a vehicle speed set by the driver (set vehicle speed). Specifically, when the driver operates the cruise control switch 27 to activate cruise control, the driving assistance control unit 12b starts the first driving assistance mode. Then, the driving assistance control unit 12b sets the vehicle speed detected by the vehicle speed sensor 28 at the time of activation of cruise control as the set vehicle speed, and accelerates or decelerates the vehicle to maintain the set vehicle speed. Furthermore, when the set vehicle speed is changed by the cruise control switch 27, the driving assistance control unit 12b accelerates or decelerates the vehicle to maintain the changed set vehicle speed. Furthermore, when the brake switch 25 detects that the brake pedal 24 is depressed, the driving assistance control unit 12b terminates the cruise control.

[0024] The second driving assistance mode is a so-called accelerator priority mode in which acceleration is performed in response to accelerator operation by the driver. Specifically, the driving assistance control unit 12b starts the second driving assistance mode when the accelerator sensor 23 detects depression of the accelerator pedal 22 while the first driving assistance mode is being executed, and ends the second driving assistance mode when depression of the accelerator pedal 22 is no longer detected.

[0025] The third driving assistance mode is a so-called following mode in which the host vehicle 1 travels while maintaining a certain inter-vehicle distance when the inter-vehicle distance to the preceding vehicle becomes short. Specifically, while the first driving assistance mode or the second driving assistance mode is being executed, the driving assistance control unit 12b detects a vehicle ahead of the host vehicle 1 (hereinafter referred to as the preceding vehicle) using the object detection sensor 29F at the front of the vehicle, and starts the third driving assistance mode when the inter-vehicle distance to the preceding vehicle (hereinafter referred to as the preceding vehicle distance Df) becomes less than a predetermined preceding vehicle distance threshold D1, and ends the third driving assistance mode when the preceding vehicle distance Df becomes equal to or greater than the preceding vehicle distance threshold D1.

[0026] Furthermore, when the lane change detection unit 12a detects that the host vehicle 1 has moved ahead of another vehicle, the driving assistance control unit 12b of this embodiment can execute deceleration mitigation control to make deceleration in the first driving assistance mode more gradual than usual. The deceleration mitigation control may, for example, change the deceleration rate to a rate lower than usual, or may delay the timing of starting deceleration by a predetermined time compared to usual. Furthermore, in the deceleration mitigation control of this embodiment, it is desirable to decelerate to a level that does not turn on the brake lights during deceleration, but in deceleration that does turn on the brake lights, the start of turning on the brake lights may be delayed.

[0027] Specifically, Fig. 2 shows an explanatory diagram illustrating a situation in which the host vehicle 1 equipped with a driving assistance control device changes course, passes beside the preceding vehicle, and moves ahead of it, so-called overtaking, and a situation in which deceleration mitigation control by the driving assistance control unit 12b is executed will be described based on the same diagram. The road shown in Fig. 2 is a two-lane expressway, with the lane on the left side of the host vehicle 1's traveling direction being the first lane L1 (so-called driving lane), the lane on the right side being the second lane L2 (so-called overtaking lane), and the line between the first lane L1 and the second lane L2 being the boundary line BL (so-called lane boundary line).

[0028] 2(a), another vehicle 2 is traveling ahead of the host vehicle 1 at a slower speed than the host vehicle 1. At this time, the driving assistance control unit 12b is driving in the first driving assistance mode of the cruise control. Note that the preceding vehicle distance Df to the preceding vehicle 2 is assumed to be equal to or greater than the preceding vehicle distance threshold D1.

[0029] 2(b) is a situation in which the driver of the vehicle 1 depresses the accelerator pedal in order to overtake the other vehicle 2 from the situation in (a) and has completed a lane change to the second lane L2. At this time, the driving assistance control unit 12b transitions from the first driving assistance mode to the second driving assistance mode in response to the depression of the accelerator pedal.

[0030] The situation shown in (c) of FIG. 2 is a situation in which the host vehicle 1 has overtaken the other vehicle 2 from the situation in (b) and has completed a lane change back to the first lane L1. At this time, when the accelerator pedal is released, the driving assistance control unit 12b transitions from the second driving assistance mode to the first driving assistance mode. Furthermore, when the object detection sensor 29B at the rear of the vehicle detects that the host vehicle 1 has moved ahead of the other vehicle 2 as a result of the lane change, the driving assistance control unit 12b executes deceleration reduction control to make the deceleration rate in the first driving assistance mode more gradual than normal. Particularly in this embodiment, the deceleration reduction control is executed when the following vehicle distance Dr to the other vehicle 2 is less than a predetermined following vehicle distance threshold D2 within a predetermined time after the lane change. In the above, it was stated that deceleration mitigation control is executed when the object detection sensor 29B at the rear of the vehicle detects that the host vehicle 1 has moved ahead of the other vehicle 2 as a result of changing lanes, and the following vehicle distance Dr to the other vehicle 2 is less than the predetermined following vehicle distance threshold D2 within a predetermined time after the lane change. However, this is not limited to this, and the driving assistance control unit 12b may execute deceleration mitigation control when either the object detection sensor 29B at the rear of the vehicle detects that the host vehicle 1 has moved ahead of the other vehicle 2 as a result of changing lanes, or the following vehicle distance Dr to the other vehicle 2 is less than the predetermined following vehicle distance threshold D2 within a predetermined time after the host vehicle 1 has changed lanes.

[0031] 3 is a flowchart showing the control procedure of the cruise control in the driving assistance control device of the host vehicle 1. The cruise control executed by the ECU 12 will be described below with reference to the flowchart of FIG.

[0032] First, in step S100, the lane change detection unit 12a of the ECU 12 determines whether or not the host vehicle 1 has changed lanes. If the determination result in step S100 is true (Yes), that is, if a lane change has occurred, the ECU 12 proceeds to step S101. On the other hand, if the determination result in step S100 is false (No), that is, if a lane change has not occurred, the ECU 12 returns from the routine.

[0033] In step S101, the driving assistance control unit 12b of the ECU 12 determines whether the inter-vehicle distance to the preceding vehicle (preceding vehicle distance Df) is less than a predetermined preceding vehicle distance threshold D1 that has been set in advance. That is, in step S101, it is determined whether the host vehicle 1 is approaching the preceding vehicle. If the determination result in step S101 is true (Yes), that is, if the inter-vehicle distance to the preceding vehicle is less than the predetermined preceding vehicle distance threshold D1, the ECU 12 proceeds to step S102. On the other hand, if the determination result in step S101 is false (No), that is, if the preceding vehicle distance Df is equal to or greater than the predetermined preceding vehicle distance threshold D1, the ECU 12 proceeds to step S103.

[0034] In step S102, the driving assistance control unit 12b of the ECU 12 executes cruise control in the third driving assistance mode (following mode), and then returns from the routine.

[0035] On the other hand, in step S103, the driving assistance control unit 12b of the ECU 12 determines whether or not the driver is depressing the accelerator pedal. If the determination result in step S103 is true (Yes), that is, if the accelerator sensor 23 detects depression of the accelerator pedal 22, the ECU 12 proceeds to step S104. On the other hand, if the determination result in step S103 is false (No), that is, if the accelerator sensor 23 does not detect depression of the accelerator pedal 22, the ECU 12 proceeds to step S105.

[0036] In step S104, the driving assistance control unit 12b of the ECU 12 executes cruise control in the second driving assistance mode (accelerator priority mode), and then returns from the routine.

[0037] Meanwhile, in step S105, the driving assistance control unit 12b of the ECU 12 determines whether the following vehicle distance Dr is less than a predetermined following vehicle distance threshold D2. That is, in step S105, it is determined whether the following vehicle is close. If the determination result in step S105 is false (No), that is, if the inter-vehicle distance to the following vehicle is equal to or greater than the predetermined following vehicle distance threshold D2, that is, if the distance between the host vehicle 1 and the following vehicle is sufficiently far or there is no following vehicle, the process proceeds to step S106. On the other hand, if the determination result in step S106 is true (Yes), that is, if the inter-vehicle distance to the following vehicle is less than the predetermined following vehicle distance threshold D2, the ECU 12 proceeds to step S107.

[0038] In step S106, the driving assistance control unit 12b of the ECU 12 executes cruise control in the first driving assistance mode (constant speed mode) and returns the routine. In this case, deceleration in the first driving assistance mode is performed at a normal deceleration rate.

[0039] On the other hand, in step S107, the driving assistance control unit 12b of the ECU 12 executes cruise control in the first driving assistance mode (constant speed mode) in which deceleration is reduced by deceleration reduction control, and then returns from the routine.

[0040] As described above, the driving assistance control device for a vehicle according to this embodiment executes deceleration mitigation control to slow down deceleration in the first driving assistance mode more slowly than normal when the lane change detection unit of the host vehicle 1 detects that the host vehicle 1 has moved ahead of another vehicle 2. This makes it possible to mitigate discomfort felt by the driver of the following vehicle even when the host vehicle 1 moves ahead of another vehicle. It is also possible to suppress braking by the following vehicle. In this way, the driving assistance control device for a vehicle can perform deceleration taking into account the following vehicle when driving using cruise control.

[0041] This concludes the description of the embodiment of the present invention, but the aspects of the present invention are not limited to this embodiment.

[0042] In the above embodiment, the lane change detection unit 12a detects that the host vehicle has moved in front of another vehicle using the object detection sensor 29B at the rear of the vehicle, but this is not limited to this. For example, the object detection sensors 29L and 29R at the sides of the vehicle may detect another vehicle to the side of the host vehicle 1, and then the host vehicle may overtake the other vehicle, lose detection of the other vehicle, and change lanes to the lane where the other vehicle was within a predetermined time, thereby detecting that the host vehicle has moved in front of the other vehicle.

[0043] In the above embodiment, the deceleration reduction control has been described using an example of a situation in which the host vehicle overtakes another vehicle as shown in Fig. 2, but the situation in which the deceleration reduction control is executed is not limited to this. For example, the deceleration reduction control is executed in a so-called overtaking situation in which the host vehicle is originally traveling in a different lane from the other vehicle, passes the side of the other vehicle, and then moves in front of the other vehicle. Note that if there is a preceding vehicle in front of the host vehicle after changing lanes, deceleration using the third driving assistance mode (following mode) is prioritized if the preceding vehicle distance Df is less than a predetermined preceding vehicle distance threshold D1.

[0044] In the above embodiment, the host vehicle is a commercial vehicle such as a bus or truck, but it may also be a passenger car. Furthermore, while the host vehicle is an engine vehicle using an engine as a drive source, the present invention can also be applied to an electric vehicle using a motor as a drive source, a hybrid electric vehicle using an engine and a motor as drive sources, and the like. When the present invention is applied to an electric vehicle using a motor as a drive source, a hybrid electric vehicle using an engine and a motor as drive sources, and the like, for example, the drive unit 10 (drive source) in the above embodiment and FIG. 1 can be applied in place of or in addition to the engine. [Explanation of symbols]

[0045] 1. Your vehicle 2 Other vehicles 10 Drive unit 11 Braking part 12 ECU 12a Lane change detection unit 12b Driving assistance control unit 20FL, 20FR front wheel 20RL, 20RR rear wheel 21FL, 21FR, 21RL, 21RR drum brakes 22 Accelerator pedal 23 Accelerator sensor 24 Brake pedal 25 Brake switch 26 Directional sensor 27 Cruise control switch 28 Vehicle speed sensor 29 Object detection sensor D1 Preceding vehicle distance threshold D2 Following vehicle distance threshold Df Distance to preceding vehicle Dr. Distance from following vehicle L1 Lane 1 L2 Second lane BL boundary line

Claims

[Claim 1] A driving assistance control device for a vehicle that automatically adjusts vehicle speed by controlling a drive unit and a brake unit of the vehicle, a driving assistance control unit having a first driving assistance mode that controls the host vehicle to maintain a vehicle speed set by a driver, and a second driving assistance mode that, when an accelerator pedal operation is performed by the driver, accelerates the host vehicle in accordance with the accelerator pedal operation; a lane change detection unit that detects when the host vehicle changes lanes and moves in front of another vehicle, The driving assistance control unit is capable of executing deceleration mitigation control to make deceleration in the first driving assistance mode more gradual than normal deceleration after the lane change detection unit detects that the other vehicle has moved ahead of the other vehicle. Vehicle driving assistance control device.

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