Travel control device

Abstract

Provided is a travel control device mounted to a vehicle, the travel control device comprising a computer device which executes control of causing an own vehicle to carry out constant travel at a set speed or causing the own vehicle to carry out travel while following a preceding vehicle. Moreover, the computer device comprises: a control target setting unit which carries out, for a vehicle detected on a merging lane, which is a path merging to a lane on which the own vehicle is traveling, processing of determining whether or not the vehicle matches a vehicle intending to enter immediately before the own vehicle and registers the vehicle as a merging vehicle according to the determination; and a following control unit which considers the merging vehicle registered by the control target setting unit as a following control target to carry out following processing.

Description

Technical Field

[0001] The present invention relates to a driving control device mounted on a vehicle.

Background Art

[0002] In the description of Patent Document 1 below, a configuration including a driving support unit, a communication unit, a range acquisition unit, and a vehicle setting unit discloses the processing on the vehicle side that attempts to merge onto the main line. Specifically, the driving support unit executes a process of calculating a target driving speed when the vehicle is traveling on the merging lane. The communication unit communicates with a vehicle traveling on the main line side where the vehicle attempts to merge. The range acquisition unit acquires a detection range for detecting a vehicle that may reach the merging point at the same time as the merging vehicle among the vehicles traveling on the main line side road. When there is a vehicle that can communicate within the detection range acquired by the range acquisition unit, the vehicle setting unit sets at least one of the communicable vehicles as a vehicle to be merged in front of it. In this configuration, when the vehicle to be merged is set, the driving support unit calculates a target driving speed for merging in front of the vehicle to be merged.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In ACC (Adaptive Cruise Control), driving control is performed to maintain a target inter-vehicle distance by setting a target acceleration based on the speed and inter-vehicle distance between the host vehicle and the preceding vehicle. Considering the vehicle side traveling on the main line, at merging points provided at interchanges, service areas, etc. on motor vehicle-only roads such as highways, the driver of the vehicle traveling on the main line side often turns off ACC.

[0005] Generally, ACC performs preceding vehicle registration targeting a preceding vehicle traveling ahead of the host vehicle for maintaining a following distance, and causes the host vehicle to maintain an appropriate following distance from the preceding vehicle. For a vehicle traveling on a merging lane, preceding vehicle registration is to be performed when the vehicle enters the host vehicle's traveling lane. However, at this time, the merging vehicle often has a low speed, and the driver of the host vehicle often cancels the ACC with the intention of maintaining an appropriate following distance from the merging vehicle due to this speed difference. This is the cause of reducing the operation rate of ACC. On the other hand, if a vehicle traveling on a merging lane is arbitrarily set as an ACC target, inter-vehicle distance maintenance control is also performed on a vehicle that has no intention of entering in front of the host vehicle, and smooth driving cannot be achieved due to sudden braking or the like.

[0006] Therefore, an object of the present invention is to enable smooth driving while continuing the ACC even at the time of merging.

Means for Solving the Problem

[0007] A driving control device according to an embodiment of the present invention is a driving control device having a computer device that performs control to cause the host vehicle to travel at a set vehicle speed or to follow a preceding vehicle, wherein the computer device performs a determination process on the suitability of a vehicle detected in a merging lane, which is a merging path to the lane in which the host vehicle is traveling, being a vehicle that intends to enter immediately in front of the host vehicle, and registers it as a merging vehicle to be a following control target according to the determination, and includes a control target setting unit that performs a following process with the merging vehicle registered by the control target setting unit as a following control target, and in the determination process of the suitability, the control target setting unit performs a process of comparing a collision margin time between the host vehicle and the vehicle to be determined with a threshold value, and when the collision margin time is less than or equal to the threshold value, makes a determination of no element to register the vehicle to be determined as a following control target, and selects the threshold value so that the distance measured between the vehicle and the vehicle to be determined is long and the time becomes long. is self The longer the distance measured between the vehicle and the vehicle to be determined how short Select so that the time becomes long.

Effect of the Invention

[0008] According to the present invention, it becomes possible to register, as a following control target, a vehicle on a merging lane that is assumed to enter immediately in front of the host vehicle. As a result, from the time before the merging vehicle enters the traveling lane of the host vehicle, speed control assuming the merging vehicle is performed by ACC, and smooth traveling becomes possible without canceling the ACC. Therefore, the safety of traveling by ACC is improved and the operation rate of ACC is also improved.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the traveling control device of the present invention will be described. It is assumed that the traveling control device is mounted on a vehicle and constitutes a part of a vehicle control system in the vehicle. For the sake of explanation, the "merging vehicle" refers to a vehicle in a merging lane, which is a merging road for merging into the lane on which the host vehicle is traveling. In the present embodiment, for example, among the merging vehicles traveling in the merging lane, a vehicle that intends to enter the lane on which the host vehicle is traveling is registered as an object of follow-up control by ACC.

[0011] <1. Configuration of Vehicle Control System> FIG. 1 shows a vehicle control system 1. The vehicle control system 1 is mounted on a vehicle 100 and controls the traveling of the vehicle 100. The vehicle control system 1 is composed of a plurality of hardware components. And as one of the hardware components constituting the vehicle control system 1, a traveling control device 2 according to the embodiment is provided.

[0012] This vehicle control system 1 includes a traveling control device 2 and, as ACC, can perform control to make the host vehicle travel at a set vehicle speed or make the host vehicle follow a preceding vehicle. Note that FIG. 1 shows mainly the configuration of the main part related to the present invention among the configurations provided in the vehicle control system 1. Therefore, the vehicle control system 1 may include configurations not shown in FIG. 1. Also, the vehicle control system 1 does not necessarily need to include all the configurations shown in the figure.

[0013] The vehicle control system 1 includes a traveling control device 2, an external environment recognition device 3, a map locator 4, a communication unit 5, an engine control unit 7, a transmission control unit 8, a brake control unit 9, a steering control unit 10, an engine-related actuator 12, a transmission-related actuator 13, a brake-related actuator 14, a steering-related actuator 15, and sensors / operators 16. The vehicle control system 1 also includes, for example, a GNSS receiver 21 which is a receiver for a Global Navigation Satellite System (GNSS), and a map database (DB) 22 in which high-precision map data is stored.

[0014] The travel control device 2, the external environment recognition device 3, the communication unit 5, the map locator 4, the engine control unit 7, the transmission control unit 8, the brake control unit 9, and the steering control unit 10 are interconnected via a bus 17.

[0015] The external environment recognition device 3 is a device having a function for recognizing the external environment of the vehicle 100 and acquiring external environment information, and is configured by, for example, a microcomputer including a Central Processing Unit (CPU), a Read Only Memory (ROM), a Random Access Memory (RAM), and the like.

[0016] The external environment recognition device 3 includes a stereo camera 18 capable of imaging the front of the vehicle 100, an image processing unit 19 that performs various processes on the image acquired from the stereo camera 18, a radar device 20 such as a millimeter-wave radar or a lidar, and other sensing devices.

[0017] The stereo camera 18 includes a plurality of imaging units, each of which is configured to include a camera optical system and an imaging element. An object image is formed on the imaging surface of the imaging element by the camera optical system, and an electrical signal corresponding to the received light amount is obtained in pixel units. Each imaging unit is installed so as to enable distance measurement by a so-called stereo imaging method. Then, the electrical signal obtained by each imaging unit is subjected to A / D conversion and predetermined correction processing, and is supplied to the image processing unit 19 as a digital image signal (imaging image data) representing a luminance value with a predetermined gradation in pixel units.

[0018] The image processing unit 19 is composed of a microcomputer equipped with, for example, a CPU, ROM, RAM, etc. Based on the captured image data obtained by an imaging unit such as the stereo camera 18, it executes predetermined image processing related to the recognition of the external environment of the vehicle. The image processing by the image processing unit 19 is performed using a storage unit such as a non-volatile memory provided in the external environment recognition device 3.

[0019] The image processing unit 19 executes various image processes based on each captured image data obtained by stereo imaging, and recognizes forward information such as three-dimensional object data in front of the host vehicle and lane lines (such as center lines and lane boundary lines). Then, based on these recognized information, etc., it detects the road and lane (host vehicle running lane) on which the host vehicle is traveling, and objects on the host vehicle running lane. For example, it detects a preceding vehicle traveling ahead of the host vehicle, white line data, guardrail existing along the road, side wall data such as curbs, three-dimensional object data such as vehicles, a stop line, a traffic signal, a level crossing, a crosswalk, a lane, etc. Also, depending on the viewing angle, arrangement, etc. of the stereo camera 18, the image processing unit 19 can also detect a vehicle traveling parallel to the host vehicle. A vehicle traveling parallel is, for example, a merging vehicle traveling on a merging lane.

[0020] Also, the image processing unit 19 can recognize surrounding objects based on the captured image of the stereo camera 18 and can also recognize their behaviors. For example, it is also possible to recognize the speed, acceleration (positive or negative acceleration due to acceleration or deceleration), change in the traveling direction, blinking of the turn signal lamp, etc. of a preceding vehicle or a merging vehicle.

[0021] The image processing unit 19 calculates information on various surrounding environments as described above, for example, for each frame of the captured image data, and sequentially stores the calculated information in the storage unit.

[0022] The driving control device 2 is composed of a microcomputer equipped with, for example, a CPU, ROM, RAM, etc. The driving control device 2 executes various driving control processes for driving support based on information obtained from the external environment recognition device 3, the map locator 4, the communication unit 5, various sensors provided in the sensor / operator group 16, and operation input information, etc.

[0023] This travel control device 2 is connected via a bus 17 to each of the control units including an engine control unit 7, a transmission control unit 8, a brake control unit 9, and a steering control unit 10, all of which are also composed of microcomputers, and can perform mutual data communication with these control units. The travel control device 2 gives instructions to the necessary control units among the above-mentioned control units to execute operations related to driving support (driving support control).

[0024] Examples of the driving support control executed by the travel control device 2 include, for example, auto lane keep control, collision damage mitigation braking control (AEB: Autonomous Emergency Braking), cruise control with vehicle distance control (ACC), and automatic lane change control.

[0025] In the figure, as functions in the travel control device 2, functions as a control target setting unit 2a and a following control unit 2b are shown. These are some functions related to ACC and are functions realized by program modules.

[0026] And the control target setting unit 2a performs a process of setting a following control target for ACC. Normally, the control target setting unit 2a sets a preceding vehicle traveling ahead of the host vehicle as the following control target for ACC. However, in the case of this embodiment, a merging vehicle detected in the merging lane is also set as the following control target for ACC. For example, for a vehicle detected in a merging lane, which is a merging road into the lane in which the host vehicle is traveling, the control target setting unit 2a performs a determination process on the suitability of the vehicle's intention to enter immediately in front of the host vehicle, and performs a process of registering the merging vehicle as a following control target according to the determination.

[0027] The following distance control unit 2b performs a target acceleration setting process in order to perform following driving while maintaining a target inter-vehicle distance with respect to a vehicle that is the following control target of the ACC, for example, a preceding vehicle. In particular, in the case of the present embodiment, the following distance control unit 2b performs a merging-corresponding following process when a merging vehicle is the following control target. The merging-corresponding following process is a process that allows a shorter inter-vehicle distance than the target inter-vehicle distance in a normal following process in which a preceding vehicle traveling in the same lane as the host vehicle is the following control target.

[0028] The communication unit 5 is capable of performing network communication, so-called V2V communication (vehicle-to-vehicle communication), and vehicle-road communication. The driving control device 2 can acquire various information received by the communication unit 5. Further, the communication unit 5 can also acquire various information, such as surrounding environment information and road information of the current location, by network communication such as the Internet.

[0029] The sensors / operators 16 comprehensively represent various sensors and operators provided in the vehicle 100. Examples of the sensors included in the sensors / operators 16 include a vehicle speed sensor 16a that detects the speed of the host vehicle, an engine speed sensor 16b that detects the rotational speed of the engine, an accelerator opening sensor 16c that detects the accelerator opening from the depression amount of the accelerator pedal, a steering angle sensor 16d that detects the steering angle, a yaw rate sensor 16e that detects the yaw rate, and a brake switch 16f that is turned on or off according to the operation or non-operation of the brake pedal.

[0030] Examples of the operators in the sensors / operators 16 include an ignition switch 16X for instructing the start / stop of the engine, an operation lever 16Y of the turn signal, and an operator 16Z for switching, for example, the on / off or control mode of the ACC as an operation related to driving support control. Note that these are merely examples, and various other sensors and operators may be provided.

[0031] Various detection signals and operation signals from the sensor / operator group 16 are supplied to the necessary parts such as the travel control device 2, the engine control unit 7, the transmission control unit 8, the brake control unit 9, and the steering control unit 10.

[0032] Based on the detection signals from a predetermined sensor in the sensor / operator group 16 and the operation input information by the operator, etc., the engine control unit 7 controls various actuators provided as the engine-related actuators 12. As the engine-related actuators 12, various actuators related to engine drive such as a throttle actuator that drives a throttle valve and an injector that performs fuel injection are provided.

[0033] Based on the detection signals from a predetermined sensor in the sensor / operator group 16 and the operation input information by the operator, etc., the transmission control unit 8 controls various actuators provided as the transmission-related actuators 13. As the transmission-related actuators 13, for example, actuators for performing shift control of an automatic transmission are provided.

[0034] Based on the detection signals from a predetermined sensor in the sensor / operator group 16 and the operation input information by the operator, etc., the brake control unit 9 controls various actuators provided as the brake-related actuators 14. As the brake-related actuators 14, various brake-related actuators such as a hydraulic control actuator for controlling the output hydraulic pressure from the brake booster to the master cylinder and the hydraulic pressure in the brake fluid piping are provided.

[0035] The steering control unit 10, for example, obtains the necessary steering torque according to the target steering angle given from the travel control device 2, and realizes the necessary automatic steering by controlling the steering-related actuators 15.

[0036] The map locator 4 can accurately identify the current position of the vehicle 100 using the GNSS receiver 21 and the map DB 22. For example, the map locator 4 can identify not only the road on which the vehicle 100 is traveling but also the driving lane. For example, based on the information from the map locator 4, the driving control device 2 can recognize the presence of a merging lane on an exclusive motorway for automobiles, including the start position to the end position of the merging lane. It can also recognize the lane in which the vehicle 100 is traveling. Note that the map locator 4 includes not only a narrow - sense locator used for determining a driving route in autonomous driving but also a navigation system using GNSS, etc. That is, it refers to something that can acquire the current position and surrounding road information, etc.

[0037] <2. Overview of Merging Control> The overview of the ACC control during merging in this embodiment will be described. Hereinafter, for the purpose of distinguishing the vehicle 100 in the above - mentioned configuration from the merging vehicle 150 and the preceding vehicle 200, it is denoted as the "host vehicle 100".

[0038] FIG. 2 shows a situation where the host vehicle 100 is traveling on the driving lane 300 on an exclusive motorway. In particular, it shows a location where there is a merging lane 301 for merging into the driving lane 300. This figure shows an example where there is also a passing lane 302. And when the host vehicle 100 is following the preceding vehicle 200 by ACC, it represents a situation where the merging vehicle 150 in the merging lane 301 is about to enter the driving lane 300 in front of the host vehicle 100.

[0039] Note that the dashed line shown diagonally forward from the host vehicle 100 indicates the range of the field of view 400 of the stereo camera 18. Also, for the merging lane 301, the start position PS and the end position PE are shown. The driving route from this start position PS to the end position PE is called the merging lane 301. The starting position PS is a position where it is possible to merge into the driving lane 300 which is the main line, for example, a position where a lane as the merging lane 301 starts to be in contact with the driving lane 300. The ending position PE is a position where the merging lane 301 no longer exists.

[0040] Also, the distance in the Z direction (travel direction) between the host vehicle 100 and the merging vehicle 150 is defined as the distance dZ, and the distance in the Z direction between the host vehicle 100 and the preceding vehicle 200 is defined as the distance dZP.

[0041] Here, it is assumed that the merging vehicle 150 is presumed to be attempting to enter immediately in front of the host vehicle 100, that is, between the host vehicle 100 and the preceding vehicle 200. In the present embodiment, in such a case, the host vehicle 100 registers the merging vehicle 150 as an object of follow-up control by ACC (hereinafter, also referred to as "ACC registration"), thereby realizing smooth merging and natural acceleration and deceleration of the host vehicle 100.

[0042] Regarding ACC in such a merging opportunity, the following points are considered. First, if all the vehicles in the merging lane 301 are registered as objects of follow-up control, the host vehicle 100 will be subject to a sharp deceleration, which is likely to result in an undesirable driving state for the following vehicle 250. Therefore, the intention of the merging vehicle 150 is estimated, and the merging vehicle 150 that will enter immediately in front of the host vehicle 100 is selected and registered as an object of follow-up control. This enables smooth merging and ensures that as little sharp deceleration as possible occurs during the driving of the host vehicle 100 by ACC.

[0043] For this purpose, ACC registration is performed considering all or part of the following points. · Based on the information from the map locator 4, vehicles closer to the ending position PE of the merge are more likely to be registered. · The TTC (Time To Collision) until the host vehicle 100 and the merging vehicle 150 meet at the merging point is used to determine the appropriateness of ACC registration. · The selection condition based on acceleration is used to determine the appropriateness of ACC registration. ·The selection condition based on the lateral position is used to determine the applicability of ACC registration. The lateral direction is a direction substantially perpendicular to the traveling direction of the vehicle, that is, the lane direction. Therefore, it can be said that the lateral direction corresponds to the vehicle width direction. Thereby, the merging vehicle 150 traveling at a position close to the traveling lane 300 is selected.

[0044] In addition, when the merging vehicle 150 overtakes the host vehicle 100 from behind or in the case of merging during a curve with a small radius of curvature, the timing for registering as a follow-up control target may be delayed. Therefore, ACC registration is also performed on the merging vehicle 150 whose vehicle body side is recognized by the image of the stereo camera 18. This means not waiting until the vehicle body rear can be recognized. In addition, there may be cases where the white line cannot be recognized due to blurring or snowfall, or cases where ACC registration of a merging vehicle cannot be performed during a curve with a small radius of curvature. Therefore, the effective lateral position may be enlarged or reduced based on the preceding vehicle 200. By these means, it becomes possible to select the merging vehicle 150 for ACC registration using only the information of the map locator 4 and the image information of the stereo camera 18 without using a millimeter-wave radar, a lidar (LiDAR: light detection and ranging), or vehicle-to-vehicle communication for detecting the merging vehicle.

[0045] In the present embodiment, examples of cases where the merging vehicle 150 performs ACC registration and cases where it does not perform ACC registration are illustrated in each case (CASE1, CASE2, CASE3, CASE4) of FIG. 3.

[0046] ·CASE1 This is a case where the host vehicle 100, the preceding vehicle 200, and the merging vehicle 150 are each traveling at 100 km / h. That is, it is a case where a merging vehicle 150 with a small vehicle speed difference enters the viewing angle of the stereo camera 18 in the presence of the preceding vehicle 200. In this case, the merging vehicle 150 is registered for ACC assuming a high possibility that the merging vehicle 150 will enter just in front of the host vehicle 100.

[0047] ·CASE2 This is the case where the host vehicle 100 and the preceding vehicle 200 are each traveling at 100 km / h, and the speed of the merging vehicle 150 is 60 km / h. Since the speed difference between the host vehicle 100 and the merging vehicle 150 is large, it is assumed that the host vehicle 100 will overtake the merging vehicle 150. Therefore, regardless of the presence or absence of the preceding vehicle 200, it is considered that the possibility of the merging vehicle 150 entering immediately in front of the host vehicle 100 is low, and the merging vehicle 150 is not registered for ACC. However, when the merging vehicle 150 is near the end position PE, it is registered for ACC to achieve a smooth merge.

[0048] ·CASE3 This is the case where the host vehicle 100 is traveling at 100 km / h and the speed of the merging vehicle 150 is 80 km / h. However, it is assumed that the acceleration of the merging vehicle 150 is large. In this case, although the speed difference between the host vehicle 100 and the merging vehicle 150 is large, there is a high possibility that the merging vehicle 150 will accelerate and enter immediately in front of the host vehicle 100. Therefore, the merging vehicle 150 is registered for ACC.

[0049] ·CASE4 This is the case where the host vehicle 100 is traveling at 30 km / h and the speed of the merging vehicle 150 is 20 km / h. That is, it is a traffic jam. For example, if the speed of the host vehicle 100 is below a predetermined value and there is a preceding vehicle 200, it can be determined that there is a traffic jam. In the case of a traffic jam, the speed difference between the host vehicle 100 and the merging vehicle 150 is small and the distance is also short. In such a case, the merging vehicle 150 with a short distance is registered for ACC.

[0050] The above is merely an example. In this embodiment, by selecting the merging vehicle 150 to be registered for ACC, smooth merging by ACC and natural driving of the host vehicle 100 are realized.

[0051] <3. Processing Example> A specific processing example for ACC registration of the merging vehicle 150 by the driving control device 2 performed based on the above concept will be described. Figures 4 and 5 show an example of the process for ACC registration when a merging vehicle 150 is recognized as part of the ACC process by the driving control device 2 during driving on an expressway for automobiles. This is a process executed by the driving control device 2 through the function of the control target setting unit 2a. For example, the driving control device 2 repeatedly executes the process of Figure 4 during ACC operation.

[0052] In step S101 of Figure 4, based on the information from the map locator 4, the driving control device 2 recognizes the location where the merging lane 301 exists on the expressway for automobiles, and when reaching that location, detects the remaining distance to the merging point. For example, the remaining distance is detected with the vicinity of the end position PE as the merging point.

[0053] In step S102, the driving control device 2 determines whether the host vehicle 100 is traveling in the lane to be merged, that is, the driving lane 300 in Figure 2. For example, if the host vehicle 100 is traveling in the overtaking lane 302, since the host vehicle 100 will not be merged in front, the process returns to step S101.

[0054] When the host vehicle 100 is traveling in the driving lane 300, the driving control device 2 proceeds to step S103 and determines whether the host vehicle 100 is in a state corresponding to merging, that is, whether it is in a state of accepting the merging vehicle 150 in front of the host vehicle. For example, if the host vehicle 100 is blinking the turn signal lamp, or during a curve beyond expectation or when the driver is making a large steering operation as a hazard avoidance behavior and trying to change lanes to the overtaking lane 302 side, it is assumed not to be in a merging corresponding state. In that case, since merging is not assumed, the process returns to step S101.

[0055] When the host vehicle 100 maintains traveling in the driving lane 300, that is, the lane to be merged, at the location where the merging lane 301 exists, the process of the driving control device 2 proceeds to step S104. In step S104, the driving control device 2 calculates the effective horizontal position range as the horizontal range. Confluence information obtained from the map locator 4 may be used for this calculation.

[0056] An example of setting the effective lateral position range is shown in FIG. 6. The driving control device 2 identifies the lateral area start point AS, for example, based on the driving lane 300 of the host vehicle 100. For example, the position of the white line between the driving lane 300 and the merging lane 301 is set as the area start point AS. If the white line cannot be clearly recognized in the image of the stereo camera 18 due to deterioration of the white line or weather conditions, etc., the left end position of the preceding vehicle 200, or a position shifted by a predetermined amount from the left end position toward the merging lane 301 side may be set as the area start point AS.

[0057] The driving control device 2 sets the range obtained by adding the area width W1 from this area start point AS toward the merging lane 301 side as the effective area AA. This effective area AA is calculated to determine the merging vehicle 150 to be registered. For example, there is a purpose of excluding structures other than vehicles that are misrecognized as the merging vehicle 150, and vehicles that are traveling or stopped near the road shoulder of the merging vehicle 150. Therefore, as a vehicle for which a merging intention is estimated, a range on the merging lane 301 that is relatively close to the driving lane 300 to some extent is set as the effective area AA. And the merging vehicle 150 within the effective area AA is regarded as a registration candidate.

[0058] For this reason, it is conceivable that the area width W1 is determined to be an appropriate value such as 5 m to 7 m. However, since various situations are assumed, it is desirable that the area width W1 be variable according to the conditions as follows.

[0059] For example, it is assumed that the first condition is satisfied by the OR condition of the following items. · The object recognized on the merging lane 301 is identified as a vehicle by the recognition result of the stereo camera 18 image or vehicle-to-vehicle communication, etc. · In the driving lane 300 during a curve, the inclination with respect to the traveling direction of the object is in a state where it can be determined as the merging vehicle 150.

[0060] Also, for example, it is assumed that the second condition is satisfied by the OR condition of the following items. · The object is the merging vehicle 150 that has already been registered for ACC. · The merging lane 301 is a merging path from the inside of the curve of the driving lane 300. · It is a state in which the inclination with respect to the traveling direction of the object can be determined as the merging vehicle 150 with respect to the straight driving lane 300.

[0061] Then, according to the first condition and the second condition, the area width W1 is set as follows. · Satisfying the first condition and also satisfying the second condition: Area width W1 = d1 (m) · Satisfying the first condition but not satisfying the second condition: Area width W1 = d2 (m) · Not satisfying the first condition but satisfying the second condition: Area width W1 = d3 (m) · Not satisfying the first condition and also not satisfying the second condition: Area width W1 = d4 (m) Note that d1 > d2 ≥ d3 > d4.

[0062] By doing so, the effective area AA can be set to an appropriate range for the determination of the ACC registration target according to the merging situation.

[0063] Subsequently, the travel control device 2 calculates a merging vehicle candidate to be registered in step S105 of FIG. 4. A detailed processing example of this step S105 is shown in FIG. 5.

[0064] In step S151, the travel control device 2 sets the merging vehicle 150 to be determined. That is, as the merging vehicle 150 recognized in the merging lane 301, the target for determining whether or not to be registered is set. Basically, the travel control device 2 sets one or more vehicles recognized from the image of the stereo camera 18 as the merging vehicle 150 to be determined.

[0065] Here, for example, the driving control device 2 is configured to include not only vehicles whose rear body is visible but also vehicles where only the side is visible in the determination target. FIG. 7 shows an example in which an object resembling a vehicle is recognized as frames TG1, TG2, and TG3 from the image of the stereo camera 18. Frame TG3 recognizes only the side of the vehicle body, and such a vehicle is also taken as a determination target. In this example, the vehicle in frame TG1 has already been set as the following control target for the preceding vehicle 200, and it becomes the determination target for whether to register the vehicles in frames TG2 and TG3 in the merging lane 301 for ACC.

[0066] In this step S151, the merging vehicle 150 in the merging lane 301 is set as the determination target. However, it is not always possible to accurately recognize from the image of the stereo camera 18 that it is definitely a vehicle. There may be a case where a structure other than a vehicle is misrecognized as the side of the vehicle body and is taken as the determination target. Although not shown in FIGS. 4 and 5, if no object that may be a vehicle is detected in the merging lane 301, it may be considered that there is no determination target, and the process may return to step S101 in FIG. 4.

[0067] After setting one or more objects as the determination target, in step S152 and subsequent steps in FIG. 5, the driving control device 2 checks whether each determination target has an element to be registered for ACC or is the merging vehicle 150.

[0068] First, in step S152, the driving control device 2 performs a wrap determination for each target object. This is a process of determining that there is an element for registering a vehicle that is not in the traveling lane 300 of the host vehicle 100, that is, the traveling route of the host vehicle 100. A specific example is shown in FIG. 8.

[0069] In step S201, the driving control device 2 determines whether the vehicle is already registered for ACC in the processing of the previous frame or the like. If it is already registered, in step S205, it is determined that there is a registered element. This is to continue to maintain the registration.

[0070] In each of the following processes, when it is determined that the merging vehicle 150 has elements suitable for ACC registration, it is determined as "with registration elements", and when it does not have suitable elements, it is determined as "without registration elements". For example, vehicles with many registration elements are preferentially registered for ACC. Therefore, in reality, in the case of "with registration elements", for example, it can be considered that a process of incrementing a determination counter is performed. In the case of "without registration elements", the above determination counter may be decremented, or it may not be incremented. Alternatively, in the case of "without registration elements", a registration ineligibility counter may be incremented. From step S152 to step S157, for the merging vehicle 150 to be determined, the suitability of ACC registration is confirmed from various viewpoints, the presence or absence of registration elements is determined, and as a result, it is determined whether to actually perform ACC registration. Many actual processing examples can be considered.

[0071] If it is determined as unregistered in step S201 of FIG. 8, the travel control device 2 determines in step S202 whether the probability as a vehicle is high. For example, it may be determined whether it can be confirmed by some method as a vehicle. Specifically, this corresponds to the case where it is recognized as probable as a vehicle by 3D determination of an image, the case where it is recognized as a vehicle by vehicle-to-vehicle communication, etc. When it is determined that the object is probable as a vehicle, the travel control device 2 determines as "with registration elements" in step S206.

[0072] When it cannot be confirmed as a vehicle, the travel control device 2 determines in step S203 whether the object is at a short distance. In this case, the distance is determined, for example, whether the distance dZ in the Z direction (travel direction) in FIG. 2 is within a predetermined distance. For example, the predetermined distance is set to 10 m or the like. A condition that the inclination of the side surface of the object with respect to the travel direction is within 10 degrees may be added. If it corresponds, the travel control device 2 determines as "with registration elements" in step S207.

[0073] If it is not applicable in step S203, the driving control device 2 determines in step S204 whether the lap rate is 0%. The lap rate is the ratio in the width direction of the host vehicle 100 in which the object is overlapping. That the lap rate of the object recognizable from the image of the stereo camera 18 is 0% means that the object is not the preceding vehicle 200, but may be the merging vehicle 150 in the merging lane 301. In that case, the driving control device 2 determines that there is a registered element in step S208. If the lap rate is not 0%, the driving control device 2 determines that there is no registered element for the object in step S209.

[0074] The above lap determination is a process assuming that there is an element for which an object not in the driving lane 300 of the host vehicle 100, in other words, an object in the merging lane 301 should be registered. As an exception to this, even if the lap rate is not 0%, already registered merging vehicles 150, vehicles whose sides can be confirmed at a short distance, etc. are not excluded from ACC registration.

[0075] Subsequently, the driving control device 2 determines in step S153 of FIG. 5 whether it was registered as the preceding vehicle 200 for ACC target before the current frame. If it is registered, it is determined that there is no registered element. If it was not previously registered as the preceding vehicle 200 for ACC target, it is determined that there is a registered element.

[0076] In step S154, the driving control device 2 performs TTC and acceleration determination. This process is shown in FIG. 9. The TTC to be determined is the TTC calculated based on the distance dZ (see FIG. 2) from the host vehicle 100 to the object considered to be the merging vehicle 150. The idea is that an object with an overly short TTC is not a registration target. This is because a merging vehicle 150 with an overly short TTC has a short distance from the host vehicle 100, and generally, a merging that unreasonably cuts in front of the host vehicle 100 is not considered to occur.

[0077] In step S220 of FIG. 9, the travel control device 2 selects such a threshold value th1 for the determination of TTC. This threshold value th1 is selected according to the speed of the host vehicle 100 and the distance to the object. For example, when the distance dZ to the object is less than 15 m, the following is done.

[0078] · When the host vehicle speed is 0 km / h or more and less than 30 km / h: th1 = t1 seconds · When the host vehicle speed is 30 km / h or more and less than 60 km / h: th1 = t2 seconds · When the host vehicle speed is 60 km / h or more and less than 100 km / h: th1 = t3 seconds · When the host vehicle speed is 100 km / h or more and less than 135 km / h: th1 = t4 seconds Note that t1 < t2 < t3 < t4.

[0079] Also, when the distance dZ to the object is 15 m or more, regardless of the host vehicle speed, for example, the threshold value th1 = 1.8 seconds. This is to make it easier to register when the distance dZ is sufficient.

[0080] In step S221, the travel control device 2 calculates the TTC with the object and determines whether the TTC is within the threshold value th1. When the TTC is not within the threshold value th1, that is, when the state where the TTC is too short does not exist, the travel control device 2 proceeds to step S223 and determines that there is a registration element.

[0081] When the TTC is determined to be too short within the threshold value th1, subsequently, the travel control device 2 selects a threshold value th2 for the determination of acceleration in step S222. Even if the TTC is short, when the acceleration of the merging vehicle 150 regarded as the object is high, it can be estimated that the merging vehicle 150 intends to merge in front of the host vehicle 100.

[0082] The acceleration threshold value th2 is selected as follows according to, for example, the relative speed between the host vehicle 100 and the object. The relative speed is (the speed of the object regarded as the merging vehicle 150) - (the host vehicle speed). Note that "s^2" indicates the square of s (seconds).

[0083] · When the relative speed is -10 km / h or more and less than 10 km / h: th2 = a1 (mm / s^2) · When the relative speed is -20 km / h or more and less than -10 km / h: th2 = a2 (mm / s^2) · When the relative speed is -30 km / h or more and less than -20 km / h: th2 = a3 (mm / s^2) · When the relative speed is -40 km / h or more and less than -30 km / h: th2 = a4 (mm / s^2) Note that a1 < a2 < a3 < a4

[0084] For example, as in this example, the slower the speed of the merging vehicle 150 is compared to the host vehicle 100, the higher the acceleration becomes the threshold value th2

[0085] In step S224, the driving control device 2 calculates the acceleration of the object and determines whether it is within the threshold value th2 And when the acceleration is equal to or greater than the threshold value th2, that is, when it can be estimated that the acceleration of the merging vehicle 150 intends to merge ahead by overtaking the host vehicle 100, the driving control device 2 proceeds to step S225 and determines that there is a registered element On the other hand, if it does not correspond, the driving control device 2 determines that there is no registered element in step S226

[0086] Although the case where the relative speed is 10 km or more is not exemplified, when the vehicle speed of the merging vehicle 150 is sufficiently faster than the host vehicle 100, for example, when the relative speed is 10 km or more, it is estimated that the merging vehicle 150 merges further ahead, that is, ahead of the preceding vehicle 200, rather than immediately in front of the host vehicle 100. Therefore, it is conceivable to determine that there is no registered element

[0087] Subsequently, the driving control device 2 performs an effective lateral position determination in step S155 of FIG. 5. A specific example is shown in FIG. 10 In step S230, the driving control device 2 acquires the information of the effective area AA calculated in step S104 of FIG. 4 earlier

[0088] In step S231, the travel control device 2 determines whether the object is within the effective area AA as the lateral position. And if the object is within the effective area AA, the travel control device 2 determines that there is a registered element in step S232. If the object is not within the effective area AA, the travel control device 2 determines in step S233 that there is no registered element. This is because the object may be a vehicle that does not intend to merge or a structure other than a vehicle.

[0089] Subsequently, the travel control device 2 makes a forward movement determination in step S156 of FIG. 5. In this case, the travel control device 2 determines whether the object is moving forward. That is, whether it can be said to be the merging vehicle 150 that is moving. Also, even if it is a vehicle, the idea is to exclude a parked vehicle. For this reason, the speed of the object is confirmed. If the object is moving forward, the travel control device 2 determines that there is a registered element, and if it is not moving forward, it determines that there is no registered element.

[0090] In step S157, the travel control device 2 determines whether there is a preceding vehicle. A processing example is shown in FIG. 11.

[0091] In step S240, the travel control device 2 determines whether the preceding vehicle 200 exists. If it does not exist, in step S242, it is set that there is a registered element for the object. This is because when the preceding vehicle 200 does not exist, a smooth merge can be realized by registering the object as an ACC target since a merge in front of the host vehicle 100 is assumed.

[0092] If the preceding vehicle 200 exists, in step S241, the travel control device 2 compares the distance dZ between the host vehicle 100 and the object with a value obtained by adding a predetermined distance d1 to the distance dZP (see FIG. 2) between the host vehicle 100 and the preceding vehicle 200. The predetermined distance d1 is, for example, 10 m.

[0093] If the distance dZ < (the distance dZP + a predetermined distance d1), the travel control device 2 determines that there is a registered element in step S243. This is because it can be determined that the merging vehicle 150, which is the object, may merge between the host vehicle 100 and the preceding vehicle 200.

[0094] On the other hand, if dZ ≥ (the distance dZP + a predetermined distance d1), the travel control device 2 determines that there is no registered element in step S244. This is because it can be estimated that the merging vehicle 150, which is the object, is likely to merge in front of the preceding vehicle 200.

[0095] So far, an example has been given in which the determination of "there is a registered element" and "there is no registered element" is made based on various determination conditions from step S152 to step S157 shown in FIG. 5. Such determination is not limited to the above example, and may be made for other conditions, and it is not necessary to perform all of the above. And in step S158, one or more candidates for the merging vehicle 150 to be registered in ACC are set based on the determination of some of these elements. For example, an object for which the number of times (count value) of determination as "there is a registered element" is equal to or more than a predetermined value is a candidate for ACC registration. Also, the number of times of determination as "there is no registered element" and the type of determination item may also be one of the criteria for whether to be a candidate.

[0096] As step S105 in FIG. 4, when the processing is performed as in FIG. 5 above, the travel control device 2 then performs priority assignment for the registration candidates in step S106 in FIG. 4. In this case, the priority is set particularly according to the traveling direction position (Z-direction position) of the merging vehicle 150 that is a candidate. For example, the closer the distance dZ to the host vehicle 100 of the merging vehicle 150, the higher the priority. Also, it is conceivable to increase the priority for the merging vehicle 150 near the end position PE. Priority assignment may be, for example, increasing the count value of "there is a registered element", or may be a process of giving weighting.

[0097] In step S107, the driving control device 2 determines the reliability of the candidate merging vehicle 150. For example, the reliability is determined based on the condition type with registered elements, the number of times, the certainty of being a vehicle, etc. When the reliability of the determination is sufficient, registration is preferentially performed. When the process of step S105 in FIG. 4 is repeated at the timing of each frame of the image of the stereo camera 18, it may be regarded as having reliability when the determination with registered elements continues during a predetermined frame period. If the reliability is not high for all of the candidate merging vehicles 150, the driving control device 2 returns to step S101. If there is a registered candidate merging vehicle 150 determined to have high reliability, it proceeds to step S108.

[0098] For the object with high reliability, the driving control device 2 checks whether it is in a safe state even if it performs ACC registration in step S108. For example, it determines whether there is a possibility of danger such as sudden braking when performing ACC registration. When there is a possibility of danger due to ACC registration, registration is not performed.

[0099] If it is determined that there is no danger, the driving control device 2 performs ACC registration on the corresponding object (merging vehicle 150) in step S109.

[0100] By performing ACC registration in this way, with the function of the following control unit 2b for the merging vehicle 150, the driving control device 2 recognizes the merging vehicle and performs following control. This enables a smooth merge and prevents the host vehicle 100 from performing unnatural driving.

[0101] <4. Effects and Modifications of the Embodiment> According to the above embodiment, the following effects can be obtained. The travel control device 2 according to the embodiment includes a computer device that performs ACC to maintain a constant speed of the host vehicle 100 at a set vehicle speed or to cause the host vehicle 100 to follow a preceding vehicle 200. Then, the computer device as the travel control device 2 performs a determination process on the suitability of a vehicle detected in a merging lane 301, which is a merging path into the lane in which the host vehicle 100 travels, being a merging vehicle 150 that intends to enter immediately in front of the host vehicle 100, as shown in FIGS. 4 and 5 for example, and has a control target setting unit 2a that registers it as a merging vehicle to be a following control target according to the determination. Further, it includes a following control unit 2b that performs ACC processing with the merging vehicle 150 registered by the control target setting unit 2a as a following control target.

[0102] As a result, among the merging vehicles 150 traveling in the merging lane 301, a merging vehicle 150 that may enter immediately in front of the host vehicle 100 is registered as a following control target. That is, it is registered at a stage before entering the traveling lane 300 of the host vehicle 100. Then, since speed control assuming such a merging vehicle 150 is performed by ACC from a point in time before such a merging vehicle 150 enters the traveling lane of the host vehicle, smooth travel becomes possible without canceling ACC.

[0103] Also, as described with reference to FIGS. 4 and 5, in order to perform a determination process on the suitability of a vehicle being a vehicle that intends to enter immediately in front of the host vehicle 100 and register it as a merging vehicle 150 to be a following control target according to the determination, not all vehicles in the merging lane 301 are unconditionally set as following control targets. Among the vehicles on the merging lane 301, a vehicle estimated to be an ACC target, that is, a vehicle with a high probability of entering in front of the host vehicle 100, is accurately registered as a following control target. This does not cause an increase in the number of vehicles targeted by ACC without reason and an increase in large acceleration and deceleration of the host vehicle 100. From these, the safety of travel by ACC is improved, and the operation rate of ACC is also improved.

[0104] Also, in the case of the processing of the embodiment, for detecting the merging vehicle 150 to be registered, it is possible without using a millimeter-wave radar, a lidar, vehicle-to-vehicle communication, etc. That is, the merging vehicle 150 to be registered as an ACC target can be selected only by the information of the map locator 4 and the information of the stereo camera 18. In this regard, there is also an advantage that it is easy to implement.

[0105] In the embodiment, in the determination process of compatibility by the function of the control target setting unit 2a, the travel control device 2 performs a process of comparing the TTC (time to collision) between the host vehicle 100 and the vehicle to be determined with a threshold value th1 selected according to the speed of the host vehicle or the distance measured between the host vehicle and the vehicle to be determined (see FIG. 9). When the TTC is too short for the vehicle to be determined traveling on the merging lane 301, that vehicle is not likely to enter immediately in front of the host vehicle 100. Therefore, it is unlikely that that vehicle is a merging vehicle entering immediately in front of the host vehicle 100. In other words, when the TTC is longer than the threshold value th1, there is a possibility that it corresponds to the merging lane. Also, the TTC indicating a state where it is easy to merge varies depending on the speed of the host vehicle 100 and the distance dZ in the traveling direction. Therefore, the threshold value th1 is selected according to the distance dZ between the vehicle to be determined and the host vehicle 100 and the speed of the host vehicle 100. As a result, when the TTC is longer than the threshold value th1, the probability that the vehicle to be determined is a merging vehicle 150 immediately in front of the host vehicle 100 increases. Therefore, by performing the determination of the TTC and the threshold value th1, the determination accuracy of the compatibility as the merging vehicle 150 to be an ACC target can be improved.

[0106] In the embodiment, in the determination process of compatibility by the function of the control target setting unit 2a, the travel control device 2 performs a process of comparing the acceleration of the vehicle to be determined with a threshold value th2 selected according to the relative speed between the vehicle to be determined and the host vehicle (see FIG. 9). When the acceleration of the vehicle to be determined traveling in the merging lane 301 is large, it can be said that there is a high possibility that the host vehicle 100 will enter and merge into the traveling lane 300 on which it is traveling. In particular, accelerating to a certain extent from a state where the TTC is short can be regarded as an action to increase the distance dZ in the traveling direction from the host vehicle 100. That is, even if the TTC is shorter than the threshold value th1, if the acceleration is greater than the threshold value th2, there is a high possibility that it is the merging vehicle 150 that will enter just in front of the host vehicle 100. Therefore, such determination can improve the determination accuracy of the compatibility as the merging vehicle 150 to be the ACC target. In addition, since the degree of acceleration for merging varies depending on the relative speed, the threshold value th2 can be selected according to the relative speed, thereby improving the determination accuracy.

[0107] In the embodiment, in the determination process of compatibility by the function of the control target setting unit 2a of the travel control device 2, an example is given in which the effective area AA in the lateral direction from the host vehicle is set according to the conditions, and a process of detecting whether or not the vehicle to be determined is within the effective area AA is performed (step S104 in FIG. 4, step S155 in FIG. 5, see FIG. 10). It is not appropriate to determine that all vehicles detected on the merging lane 301 side as viewed from the traveling lane 300 of the host vehicle 100 are merging vehicles 150. This is because there may be cases where a vehicle stopped away laterally from the traveling lane 300 is detected, or an object other than a vehicle is misrecognized and detected. Therefore, as one of the conditions for determining the merging vehicle 150, it is confirmed that the vehicle is within the effective area AA. This can improve the determination accuracy. In addition, the range of the effective area AA can be changed according to conditions such as the curve of the road, the vehicle recognition state, and the presence or absence of the preceding vehicle 200, so that it can be used as one of the appropriate determination criteria for whether or not the merging vehicle 150 will merge just in front of the host vehicle.

[0108] In the embodiment, the travel control device 2 gives an example in which a vehicle whose vehicle body side surface is recognized in the merging lane 301 is made the target of the determination process of compatibility by the function of the control target setting unit 2a. For a vehicle traveling in the merging lane 301, the rear of the vehicle body cannot be recognized unless there is a certain distance dZ in the traveling direction as seen from the host vehicle 100. Normally, for follow-up control, the rear of the preceding vehicle 200 is recognized. However, for registration as an ACC target of the merging vehicle 150, it is assumed that the registration will be delayed with only the recognition of the rear. Therefore, vehicles for which the side of the vehicle body has been recognized are also made targets of the determination process. As a result, even a vehicle traveling in the merging lane 301 with a relatively short Z distance from the host vehicle 100 can be registered as the merging vehicle 150. Accordingly, the merging vehicle 150 can be registered as an ACC target at an appropriate timing.

[0109] Note that the above embodiments are examples of implementing the present invention, and the implementation of the present invention is not limited to the above examples, and various modifications can be considered.

[0110] In addition, a program for causing a computer device to execute processes such as those in FIGS. 4, 5, 8, 9, 10, and 11 can be stored in a storage medium such as a non-volatile memory in the travel control device 2 or a non-volatile memory provided in the vehicle control system 1. Further, the program can be stored in a portable storage medium, or can be downloaded to the vehicle 100 from a server device via network communication.

Explanation of Reference Numerals

[0111] 1 Vehicle control system 2 Travel control device 2a Control target setting unit 2b Follow-up control unit 3 External environment recognition device 4 Map locator 18 Stereo camera 100 Vehicle (host vehicle) 150 Merging vehicle 200 Preceding vehicle 250 Following vehicle 300 Travel lane 301 Merging lane

Claims

1. A driving control device having a computer device that controls the host vehicle to travel at a set vehicle speed or to follow a preceding vehicle, wherein the computer device performs a determination process on the suitability of a vehicle detected in a merging lane, which is a merging road into the lane in which the host vehicle is traveling, being a vehicle that intends to enter immediately in front of the host vehicle, and registers it as a merging vehicle to be the target of following control according to the determination; a following control unit that performs a following process on the merging vehicle registered by the control target setting unit as a following control target; and the control target setting unit, in the suitability determination process, performs a process of comparing the collision margin time between the host vehicle and the vehicle to be determined with a threshold value; when the collision margin time is less than or equal to the threshold value, makes a determination without an element of registering the vehicle to be determined as a following control target; the threshold value is selected such that the longer the distance measured between the host vehicle and the vehicle to be determined, the shorter the time; a driving control device.

2. The control target setting unit, in the suitability determination process, sets an effective area in the lateral direction from the host vehicle according to conditions, and performs a process of detecting whether the vehicle to be determined is within the effective area. The driving control device according to claim 1.

3. The control target setting unit targets a vehicle whose vehicle body side surface is recognized in the merging lane for the suitability determination process. The driving control device according to claim 1 or claim 2.

4. A driving control device having a computer device that controls the host vehicle to travel at a set vehicle speed or to follow a preceding vehicle, wherein the computer device performs a determination process on the suitability of a vehicle detected in a merging lane, which is a merging road into the lane in which the host vehicle is traveling, being a vehicle that intends to enter immediately in front of the host vehicle, and registers it as a merging vehicle to be the target of following control according to the determination; a following control unit that performs a following process on the merging vehicle registered by the control target setting unit as a following control target; and the control target setting unit, in the suitability determination process, performs a process of comparing the acceleration of the vehicle to be determined with a threshold value selected according to the relative speed between the vehicle and the host vehicle. A driving control device.

Images