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. This computer device comprises: a control target setting unit which sets, to a following control target, a merging vehicle traveling on a merging lane, which is a path merging to a lane on which the own vehicle is traveling, and intending to enter the lane on which the own vehicle is traveling; and a following control unit which carries out, when the merging vehicle is set to the following control target, merging-adapted following processing which permits an inter-vehicle distance shorter than a target inter-vehicle distance used for following processing of setting, to a control target, a preceding vehicle traveling on the same lane as that of the own vehicle.

Description

Technical Field

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

Background Art

[0002] The following Patent Document 1 discloses a technique of assuming a virtual vehicle and performing follow - up driving with respect to the virtual vehicle in order to enable smooth acceleration and deceleration even when another vehicle cuts in between the host vehicle and the preceding vehicle during follow - up driving.

Prior Art Document

Patent Document

[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 according to the speeds and inter - vehicle distances of the host vehicle and the preceding vehicle. When the host vehicle is traveling on the main line of an exclusive road for automobiles such as a highway using ACC, even if there is a merging vehicle that is considered to merge in front of the host vehicle in the merging lane near an interchange or a service area merge, until the merging vehicle merges in front of the host vehicle and becomes the preceding vehicle, the merging vehicle is not an object of ACC control. As a result, there are cases where the host vehicle and the merging vehicle run side by side or are in a state close to that, making it difficult for the merging vehicle to merge into the main line. In addition, when the merging vehicle merges in front of the host vehicle and becomes an object of ACC control as the preceding vehicle of the host vehicle, in order to maintain a safe inter - vehicle distance from that vehicle, the braking of the host vehicle may act strongly, disturbing the smooth traffic flow. From the above, when driving near the merging point of the main line, the driver has to use more caution when using ACC or may turn off ACC than when driving in other places.

[0005] Therefore, an object of the present invention is to enable smooth driving while continuing ACC even at the opportunity of merging.

Means for Solving the Problems

[0006] 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 keep the host vehicle traveling at a set vehicle speed or to make the host vehicle follow a preceding vehicle. The computer device includes a control target setting unit that sets a merging vehicle detected in a merging lane, which is a merging path into the lane in which the host vehicle is traveling, as a following control target, and when the merging vehicle is set as the following control target, a following control unit that performs a merging-corresponding following process that allows a shorter inter-vehicle distance than the target inter-vehicle distance in the following process of setting a preceding vehicle traveling in the same lane as the host vehicle as the following control target. When the lap rate between the merging vehicle set as the following control target and the host vehicle is zero and the acceleration of the merging vehicle is less than a predetermined threshold, or when the target acceleration obtained by setting the merging vehicle as the following control target is less than a predetermined threshold, the target acceleration obtained by setting the merging vehicle as the following control target is invalidated, and a following process of setting a preceding vehicle traveling in the same lane as the host vehicle as the following control target is performed. When the lap rate between the merging vehicle and the host vehicle, which is the object of following control, is zero and the current speed of the merging vehicle is less than a predetermined amount compared to the speed when it is the object of following control, the following process is performed 。

Advantages of the Invention

[0007] According to the present invention, it is possible to prevent the host vehicle from suddenly decelerating in an attempt to open a gap from the merging vehicle by ACC, or from interfering with the merging vehicle by running parallel to the merging vehicle, and also to prevent the gap from being too large with respect to the merging vehicle. As a result, the natural flow at the merging point is not disturbed, and the safety of driving by ACC is improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the traveling control device of the present invention will be described. The traveling control device is mounted on a vehicle and is a device that 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 in which the host vehicle is traveling, and is a vehicle detected by the host vehicle. For example, a vehicle traveling in the merging lane and intending to enter the lane in which the host vehicle is traveling is detected as a merging vehicle.

[0010] <1. Configuration of Vehicle Control System> FIG. 1 shows a vehicle control system 1. The vehicle control system 1 is mounted on the vehicle 100 and performs traveling control of the vehicle 100. The vehicle control system 1 is composed of a plurality of hardware. And as one of the hardware constituting the vehicle control system 1, a traveling control device 2 according to the embodiment is provided.

[0011] FIG. 1 shows an example of a vehicle control system 1 mounted on a vehicle 100. This vehicle control system 1 includes a driving control device 2 and can perform control to keep the host vehicle traveling at a set vehicle speed or to follow a preceding vehicle as ACC. Note that FIG. 1 shows the configuration of the main part related to the present invention among the respective configurations included 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.

[0012] The vehicle control system 1 includes a driving 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: Global Navigation Satellite System), and a map DB (Database) 22 in which high-precision map data is stored.

[0013] The driving 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.

[0014] 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 CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc.

[0015] 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 images acquired from the stereo camera 18, a radar device 20 such as a millimeter-wave radar or a lidar, and other sensing devices.

[0016] 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 signals obtained by each imaging unit are subjected to A / D conversion and predetermined correction processing, and are supplied to the image processing unit 19 as digital image signals (imaging image data) representing luminance values with a predetermined gradation in pixel units.

[0017] The image processing unit 19 is composed of a microcomputer including, for example, a CPU, a ROM, a RAM, etc. Based on the imaging image data obtained by imaging units such as the stereo camera 18, it executes predetermined image processing related to the recognition of the external environment. The image processing by the image processing unit 19 is performed using a storage unit such as a non-volatile memory included in the external environment recognition device 3.

[0018] The image processing unit 19 executes various image processes based on each imaging image data obtained by stereo imaging, and recognizes three-dimensional object data in front of the host vehicle and front information such as lane lines (center lines, lane boundary lines, etc.). Then, based on these recognition information, etc., it detects the road and lane (host vehicle driving lane) on which the host vehicle is traveling, and objects on the host vehicle driving lane. For example, it detects a preceding vehicle traveling ahead of the host vehicle, white line data, guardrails existing along the road, side wall data such as curbs, three-dimensional object data such as vehicles, a stop line, a traffic signal, a railroad 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.

[0019] In addition, the image processing unit 19 can recognize surrounding objects based on the captured images of the stereo camera 18 and also recognize their behavior. 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 the preceding vehicle or the merging vehicle.

[0020] 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.

[0021] The travel control device 2 is composed of a microcomputer including, for example, a CPU, a ROM, a RAM, etc. The travel control device 2 executes various travel 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.

[0022] This travel control device 2 is connected via a bus 17 to each control unit of the engine control unit 7, the transmission control unit 8, the brake control unit 9, and the steering control unit 10, which are also composed of microcomputers, and it is possible to perform mutual data communication with these control units. The travel control device 2 gives instructions to the necessary control units among the above control units to execute operations related to driving support (driving support control).

[0023] 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-to-vehicle distance control (ACC), and automatic lane change control.

[0024] 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.

[0025] Then, the control target setting unit 2a performs a process of setting the following control target of ACC. The control target setting unit 2a usually sets the preceding vehicle traveling in front of the host vehicle as the following control target of ACC. However, in the case of this embodiment, the merging vehicle detected in the merging lane is also set as the following control target of ACC.

[0026] The following control unit 2b performs a process of setting a target acceleration in order to perform following driving while maintaining a target inter-vehicle distance with respect to the vehicle set as the following control target of ACC, for example, the preceding vehicle. Particularly, in the case of this embodiment, the following control unit 2b performs a following process corresponding to merging when the merging vehicle is set as the following control target. The following process corresponding to merging is a process that allows a shorter inter-vehicle distance than the target inter-vehicle distance in the normal following process in which the preceding vehicle traveling in the same lane as the host vehicle is set as the following control target.

[0027] 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. Also, the communication unit 5 can acquire various information, for example, surrounding environment information of the current location, road information, etc. through network communication such as the Internet.

[0028] The sensor / operator group 16 comprehensively represents various sensors and operators provided in the vehicle 100. Sensors included in the sensor / operator group 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, a brake switch 16f that is turned on or off according to the operation or non-operation of the brake pedal, and the like.

[0029] In addition, as operators in the sensor / operator group 16, there are an ignition switch 16X for instructing engine start / stop, a turn signal operation lever 16Y, and an operator 16Z for, for example, turning on / off ACC or switching the control mode as an operation related to driving support control, etc. Note that these are merely examples, and various other sensors and operators are provided in addition to these.

[0030] Various detection signals and operation signals from the sensor / operator group 16 are supplied to the necessary components 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.

[0031] The engine control unit 7 controls various actuators provided as engine-related actuators 12 based on detection signals from a predetermined sensor in the sensor / operator group 16, operation input information by an operator, etc. As the engine-related actuators 12, various actuators related to engine drive such as a throttle actuator for driving a throttle valve and an injector for performing fuel injection are provided.

[0032] The transmission control unit 8 controls various actuators provided as transmission-related actuators 13 based on detection signals from a predetermined sensor in the sensor / operator group 16, operation input information by an operator, etc. As the transmission-related actuators 13, an actuator for performing shift control of an automatic transmission is provided, for example.

[0033] The brake control unit 9 controls various actuators provided as brake-related actuators 14 based on detection signals from a predetermined sensor in the sensor / operator group 16, operation input information by an operator, etc. As the brake-related actuator 14, various brake-related actuators are provided, such as a hydraulic pressure control actuator for controlling the output hydraulic pressure from a brake booster to a master cylinder and the hydraulic pressure in brake fluid piping.

[0034] The steering control unit 10 obtains the necessary steering torque according to a target steering angle provided by, for example, the cruise control device 2, and controls the steering-related actuator 15 to realize the necessary automatic steering.

[0035] The map locator 4 is capable of identifying the current position of the vehicle 100 with high accuracy by using the GNSS receiver 21 and the map DB 22. For example, the map locator 4 is capable of identifying not only the road on which the vehicle 100 is traveling but also the traveling lane. For example, the cruise control device 2 can recognize the presence of a merging lane on a motorway including an expressway, and further the start and end positions of the merging lane, based on information from the map locator 4. It can also recognize the lane in which the vehicle 100 is traveling. The map locator 4 includes not only a locator in the narrow sense used for determining driving routes in autonomous driving, but also a navigation system using GNSS. In other words, it refers to a device that can obtain the current position and surrounding road information.

[0036] <2. Overview of merging control> An overview of the ACC control during merging in this embodiment will be described. In the following description, the vehicle 100 in the above configuration will be referred to as the “host vehicle 100” in order to distinguish it from the merging vehicle 150 and the preceding vehicle 200.

[0037] 2 shows a situation in which the vehicle 100 is traveling in a driving lane 300 on a highway. In particular, a merging lane 301 is present in order to merge into the driving lane 300. 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.

[0038] The dashed line shown obliquely forward from the host vehicle 100 indicates the range of the visual field 400 of the stereo camera 18. Regarding 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 shall be called the merging lane 301. The start position PS is a position where merging into the main driving lane 300 is possible. For example, it is a position where the lane as the merging lane 301 starts to be in contact with the driving lane 300. The end position PE is a position where the merging lane 301 no longer exists.

[0039] For example, in such a situation, in the conventional ACC logic, since the merging vehicle 150 is not a following control target until it enters the driving lane 300, the host vehicle 100 travels while maintaining the target inter-vehicle distance from the preceding vehicle 200. For this reason, there may be a case where the host vehicle 100 runs parallel to the merging vehicle 150, and the merging vehicle 150 cannot smoothly enter the driving lane 300.

[0040] Also, when the merging vehicle 150 enters the driving lane 300, the host vehicle 100 sets the merging vehicle 150 as a following control target. In this case, for the host vehicle 100, the inter-vehicle distance to the following control target suddenly becomes shorter. Therefore, in the ACC logic, the acceleration is changed in response to the suddenly shortened inter-vehicle distance. Specifically, it is changed to a relatively large negative acceleration (deceleration). As the behavior of the host vehicle 100, it will apply a relatively sudden brake. Then, as seen from the following vehicle 250, the host vehicle 100 seems to brake unnaturally.

[0041] That is, if the ACC for the preceding vehicle 200 is continued as it is when there is a merging vehicle 150, it may be difficult for the merging vehicle 150 to merge, or the host vehicle 100 may perform unnatural braking as viewed from the following vehicle 250, which is not desirable for maintaining smooth traffic at the merging point.

[0042] Therefore, in the present embodiment, for example, when the host vehicle is traveling on the driving lane 300 of an expressway by the map locator 4 and it is determined that the vehicle is near a merging point, the merging vehicle 150 on the merging lane 301 is set as the object of the follow-up control of the ACC before it enters the driving lane 300. And at that time, the ACC is executed as a follow-up process corresponding to merging, and by performing acceleration / deceleration control considering merging, unnecessary deceleration of the host vehicle 100 is suppressed. This is a control that temporarily allows the congestion of the inter-vehicle distance due to setting the merging vehicle 150 as the control object of the host vehicle 100.

[0043] Here, the merging vehicle 150 traveling on the merging lane 301 is the object of the follow-up control. However, vehicles whose acceleration of the merging vehicle 150, the target acceleration with respect to the merging vehicle 150, or the relative speed and relative distance from the host vehicle 100 are below a certain threshold value are not the objects of the follow-up control. Or they are excluded from the follow-up control object. For example, vehicles that are stopped on the merging lane 301 or vehicles that are traveling at an extremely low speed compared to the host vehicle 100 or the preceding vehicle 200, etc., are vehicles that are difficult to predict to merge from now on.

[0044] In addition, the follow-up process corresponding to merging in the present embodiment also corresponds to traffic jam situations. FIG. 3 shows a situation where there is a traffic jam at the merging point. In the control in the follow-up process corresponding to merging, when it is determined that there is a traffic jam, the inter-vehicle distance setting is set to be the shortest within a preset adjustable range, for example, and the target inter-vehicle distance is set for traffic jam at merging. Further, an acceleration correction value is calculated from the relative speed with the merging vehicle and the deviation between the target inter-vehicle distance and the actual inter-vehicle distance, and added to the target acceleration of the normal ACC logic. This prevents the inter-vehicle distance from opening too much. When performing control by ordinary ACC, when the inter-vehicle distance of each vehicle is congested in traffic jams, only the inter-vehicle distance in front of the host vehicle 100 is too wide, which will disrupt the traffic flow.

[0045] In addition, for the merging vehicle 150 that is the target of follow-up control, FIG. 4 shows the case where only the side surface of the vehicle body is recognized, and FIG. 5 shows the case where the rear surface is recognized. The recognition in this case means recognition from the image obtained by the stereo camera 18.

[0046] In the case of FIG. 4, usually, the rear surface of the preceding vehicle 200 indicated by the frame W0 is recognized, and follow-up driving is performed by ACC. In this state, when the side surface of the merging vehicle 150 indicated by the frame W1 enters the visual field 400 of the stereo camera 18, the driving control device 2 of the host vehicle 100 can recognize this merging vehicle 150 and set the merging vehicle 150 as the target of ACC follow-up control. In this case, when the merging vehicle 150 is set as the target of follow-up control, the vehicle interval becomes congested, but braking that rapidly widens the inter-vehicle distance, for example, widening the inter-vehicle distance to be equal to the inter-vehicle distance with the preceding vehicle 200 until then, is not performed.

[0047] In the case of FIG. 5, since the merging vehicle 150 has entered deeper into the visual field 400 of the stereo camera 18, the driving control device 2 of the host vehicle 100 is in a state where the rear surface of the merging vehicle 150 can be recognized as shown by the frame W2. After that, if it is determined that the merging vehicle 150 merges in front of the host vehicle 100 in the driving lane 300 under predetermined conditions, an appropriate target inter-vehicle distance is maintained from the relative distance and relative speed with respect to the merging vehicle 150. However, when the target acceleration by the ordinary ACC logic becomes negative (deceleration), the inter-vehicle distance setting is set to the shortest within the settable range, for example, to weaken the deceleration. Further, in the case of traffic jams, it is set to the target inter-vehicle distance for traffic jams at the merging point. Furthermore, an acceleration correction value is calculated from the relative speed with the merging vehicle and the deviation between the target inter-vehicle distance and the actual inter-vehicle distance, and added to the target acceleration of the ordinary ACC logic.

[0048] <3. Processing Example> A specific example of the merging-corresponding following process by the travel control device 2 performed with the above-described concept will be described. FIG. 6 shows an example of the process when a merging vehicle 150 is registered as an object of ACC following control as part of the ACC process by the travel control device 2 during travel on an expressway for automobiles.

[0049] As a premise of the process of FIG. 6, the travel control device 2 registers the merging vehicle 150 as an object of ACC following control by the function of the control target setting unit 2a. For example, based on information from the map locator 4, the travel control device 2 recognizes a location where the merging lane 301 exists on the expressway for automobiles, and when reaching that location, determines whether the host vehicle 100 is traveling in the travel lane 300 adjacent to the merging lane 301. And when it is determined that such a situation exists, a process of registering, as an object of ACC following control, the vehicle recognized on the merging lane 301 by the captured image of the stereo camera 18 as the merging vehicle 150 is performed. As shown in FIG. 4 described above, even when only the side surface of the merging vehicle 150 is recognized, the merging vehicle 150 can be registered as an object of following control.

[0050] FIG. 6 is a flowchart in the case of executing the merging-corresponding following process when the merging vehicle 150 is registered as an object of following control in this way. Therefore, during ACC execution, when the merging vehicle 150 is not registered as an object of following control, the travel control device 2 returns from step S101 to the normal ACC process. The normal ACC process is a process of performing acceleration / deceleration control so as to maintain a predetermined target inter-vehicle distance with respect to the preceding vehicle 200 when the preceding vehicle 200 exists, and performing constant-speed travel control at the set speed when the preceding vehicle 200 does not exist.

[0051] When the merging vehicle 150 is the target of ACC following control, the driving control device 2 repeats, as loop process LP1, the merging-corresponding following process in step S102 and the determination process in step S103. This loop process LP1 is repeated during the period in which the merging lane 301 continues and for a certain period of time after the merging lane ends. That is, when the host vehicle 100 is traveling in the driving lane 300 and the merging vehicle 150 is made the target of following control after reaching the start position PS of the merging lane 301, it is repeated from that point until a certain period of time has elapsed after the merging lane ends at the end position PE. However, depending on the determination in step S103 described later, there may be a case where this loop process LP1 is exited.

[0052] An example of the merging-corresponding following process in step S102 performed as this loop process LP1 is shown in FIG. 7. The process in FIG. 7 is a process executed by the driving control device 2 by the function of the following control unit 2b.

[0053] In step S120, the driving control device 2 calculates a target acceleration for the merging vehicle 150 using normal ACC logic. That is, the target acceleration is calculated for the merging vehicle 150 that is the target of following control in the same way as the target acceleration calculation logic for the preceding vehicle 200 that has been followed until then.

[0054] In step S121, the driving control device 2 branches the process depending on whether only the side surface of the vehicle body or the rear surface of the merging vehicle 150 that is the target of following control is recognized.

[0055] When only the side surface is recognized, the driving control device 2 proceeds to step S122 and limits the upper limit of the target acceleration to the throttle-off value.

[0056] When the merging vehicle 150 is the target of follow-up control, in a situation where only the side surface of the merging lane 301 is recognized, it can be estimated that the merging vehicle 150 is traveling on the merging lane 301 slightly ahead of the host vehicle. In this case, when compared with the inter-vehicle distance from the preceding vehicle 200, which has been the target of follow-up control until then, the inter-vehicle distance will rapidly decrease. In this state, if the target acceleration calculated in step S120 becomes 0 or more and the vehicle starts to accelerate or maintain a constant speed, there may be a movement that hinders the merging, even though an attempt is being made to allow the merging vehicle to merge in front of the host vehicle. Therefore, the upper limit of the calculated target acceleration is limited to a value corresponding to throttle-off to make it easier for the merging vehicle 150 to merge in front of the host vehicle.

[0057] After limiting the upper limit value of the target acceleration in this way, in step S127, the target acceleration is output. That is, braking according to the target acceleration is applied by the ACC.

[0058] On the other hand, at the time of step S121, in a situation where the rear of the merging vehicle 150 can be recognized, the travel control device 2 proceeds to step S123. In this case, the travel control device 2 determines whether the target acceleration based on the normal ACC logic becomes a negative value from the relative speed and relative distance with the merging vehicle 150.

[0059] The target acceleration calculated in step S120 described above is calculated based on the relative speed and relative distance with the merging vehicle 150. When it becomes a negative value, it means that deceleration is necessary. And the situation where the rear of the merging vehicle 150 is recognized can be determined as a situation just before or during the merging vehicle 150 entering in front of the host vehicle 100 in the driving lane 300. Therefore, deceleration is necessary to maintain a certain inter-vehicle distance. However, if an attempt is made to maintain the same target inter-vehicle distance as during normal driving at the time of merging, an unnecessarily long inter-vehicle distance will be opened at the merging point, and excessive braking will also be applied. Therefore, when it is determined in step S123 that deceleration is necessary, the travel control device 2 proceeds to step S124 and sets the target inter-vehicle distance to be the shortest within the settable range.

[0060] Note that if the target acceleration is not negative in step S123, this step S124 does not need to be performed.

[0061] Subsequently, in step S125, the travel control device 2 determines whether there is a preceding vehicle 200 on the travel lane 300 on which the host vehicle 100 is traveling and whether the speed of the host vehicle 100 is less than a predetermined threshold value. The threshold value can be set to a value within a range such as, for example, from 20 km / h to 40 km / h. That is, this step S125 is a process for determining whether or not it is in a traffic jam. Note that hysteresis is set for the determination in step S125. For example, less than 40 km / h is the operating condition, and the release condition is 50 km / h or more. This prevents the conditions from hunting when traveling around 40 km / h.

[0062] When the conditions of step S125 are met, it is determined that it is in a traffic jam, and the travel control device 2 proceeds to step S126. In this case, the travel control device 2 sets the inter-vehicle distance setting to be the shortest within the settable range and changes the target inter-vehicle distance to the setting for traffic jams at the time of merging. The setting for traffic jams is a short distance corresponding to a state where the vehicle intervals are congested in a traffic jam. For example, temporarily set a shorter inter-vehicle distance than the normal target inter-vehicle distance.

[0063] Also, in this step S126, the travel control device 2 calculates an acceleration correction value from the relative speed with the merging vehicle 150, the deviation between the target inter-vehicle distance and the actual inter-vehicle distance. Then, the acceleration correction value is added to the target acceleration calculated by the normal ACC logic in step S120. Note that the addition mentioned here includes cases where a negative acceleration correction value is added to a negative target acceleration, a positive acceleration correction value is added to a negative target acceleration, a negative acceleration correction value is added to a positive target acceleration, and a positive acceleration correction value is added to a positive target acceleration. That is, in the situation at that time, as a merging during traffic congestion, acceleration and deceleration are performed so that the vehicle-to-vehicle distance is not opened too much and the necessary vehicle-to-vehicle distance from the merging vehicle 150 is maintained.

[0064] Among the processes of steps S123, S124, S125, and S126 above, after performing the necessary processes according to the situation, the travel control device 2 outputs the target acceleration in step S127. That is, acceleration and deceleration are performed so that the vehicle-to-vehicle distance from the merging vehicle 150 is not opened more than necessary and excessive braking is not applied.

[0065] The above process of FIG. 7 is repeated as step S102 of FIG. 6. During this period, in step S103 of FIG. 6, the travel control device 2 determines the acceleration of the merging vehicle 150 and also determines the lap rate between the host vehicle 100 and the merging vehicle 150.

[0066] The definition of the lap rate is shown in FIG. 8. The lap rate indicates the degree of overlap in the width direction between the position of the host vehicle 100 and the merging vehicle 150. As shown in the figure, the case of a completely overlapping position relationship is defined as a lap rate of 100%, the case of a position relationship where half of the vehicle body width overlaps is defined as a lap rate of 50%, and the state where the vehicle body widths do not overlap is defined as a lap rate of 0%.

[0067] In step S103 of FIG. 6, when it is determined that the lap rate is 0%, it means that the merging vehicle 150 is still in the merging lane 301.

[0068] Also, the threshold value for the acceleration of the merging vehicle 150 is a certain negative acceleration value, and being less than the threshold value corresponds to a rapid deceleration. Therefore, the fact that the acceleration of the merging vehicle 150 is less than the threshold value means that the merging vehicle 150 is in a situation of rapid deceleration. Note that the situation of being stopped may also be determined by the relative speed.

[0069] When the wrapping rate is 0% and the acceleration of the merging vehicle 150 is less than the threshold value, it can be estimated that the merging vehicle 150 does not intend to merge. Therefore, in that case, the travel control device 2 exits the loop process LP1 and proceeds to step S104, invalidates the target acceleration obtained in step S102 with respect to the merging vehicle 150 as a following control target, and returns to the normal ACC process. That is, the merging vehicle 150 is removed from the following control target of ACC, and the process returns to the normal ACC process with the preceding vehicle 200 as the following control target.

[0070] Also, when the wrapping rate is 0% and the target acceleration with respect to the merging vehicle 150 is less than the threshold value, the travel control device 2 also exits the loop process LP1 and proceeds to step S104. This is a process considering that the acceleration of the merging vehicle 150 may not be correctly output according to the actual speed. Also, when the wrapping rate is 0% and the current speed of the merging vehicle 150 has decreased by a certain amount or more from the speed immediately after the merging vehicle 150 was registered in ACC, the travel control device 2 also exits the loop process LP1 and proceeds to step S104. This is to prevent the host vehicle 100 from following and decelerating or stopping when the merging vehicle 150 decelerates slowly and stops. In these cases as well, the process returns to the normal ACC process with the preceding vehicle 200 as the following control target.

[0071] <4. Effects and Modifications of the Embodiment> According to the above embodiment, the following effects can be obtained. The running control device 2 according to the embodiment includes a computer device that performs ACC to maintain the vehicle speed of the host vehicle 100 at a set speed or to make the host vehicle 100 follow the preceding vehicle 200. The computer device as the running control device 2 has a control target setting unit 2a that sets the merging vehicle 150 detected in the merging lane 301 as a follow-up control target for ACC. Further, the computer device as the running control device 2 performs a merging-corresponding follow-up process that allows a shorter inter-vehicle distance than the target inter-vehicle distance in the follow-up process of setting the preceding vehicle 200 traveling in the same running lane 300 as the host vehicle 100 as a follow-up control target when the merging vehicle 150 is the follow-up control target.

[0072] When the host vehicle 100 is maintaining the target inter-vehicle distance while traveling behind the preceding vehicle 200 in the same running lane 300 by normal ACC and the merging vehicle 150 enters the running lane 300, if the merging vehicle 150 is set as the follow-up control target to obtain the target inter-vehicle distance, a situation may occur where the host vehicle 100 decelerates rapidly. Therefore, the merging vehicle 150 traveling in the merging lane 301 is set as a follow-up control target for ACC before merging, and a merging-corresponding follow-up process is performed. Since this merging-corresponding follow-up process is an algorithm that allows the target inter-vehicle distance to be shortened as described in FIG. 7, it is possible to prevent the host vehicle 100 from being rapidly decelerated by ACC in an attempt to open a gap with the merging vehicle 150. Therefore, the deceleration of the host vehicle 100 is smoother even from the perspective of the following vehicle 250. Also, the gap with the merging vehicle 150 will not be too large. As a result, the natural flow at the merging point is not disturbed, and the safety of running by ACC is improved.

[0073] In addition, this also reduces the driver's need to turn off ACC at the merging opportunity and respond to the merging vehicle 150, improving the convenience of running by ACC.

[0074] Also, when the merging vehicle 150 is made the target of the ACC follow-up control while traveling in the merging lane 301, it is possible to avoid a situation where the merging vehicle 150 runs parallel to the host vehicle 100 and no opportunity for merging is given. Therefore, it is also possible to promote the smooth merging of the merging vehicle 150.

[0075] Furthermore, eliminating excessive braking control when putting the merging vehicle 150 in front of the host vehicle 100 also contributes to improving the fuel efficiency of the host vehicle 100.

[0076] In the embodiment, when the side surface of the vehicle of the merging vehicle 150 that is the target of the follow-up control is recognized and the rear surface of the vehicle is not recognized, an example is given in which in the follow-up process for merging response, the upper limit of the target acceleration of the ACC is limited to the acceleration by throttle-off (see step S122 in FIG. 7). A situation where the side surface of the merging vehicle 150 is recognized and the rear surface of the vehicle is not recognized can be presumed to be a situation where the merging vehicle 150 is traveling in the merging lane 301 looking for an opportunity to merge. Therefore, in a situation where the distance between vehicles is quickly widened with respect to the merging vehicle 150 that has become the target of the ACC follow-up control, it is acceptable to allow the distance between vehicles to be temporarily shortened. However, it is desirable to gradually widen the distance between vehicles to achieve smooth merging. Therefore, the upper limit of the target acceleration, that is, the negative acceleration for deceleration in this case, is limited to the acceleration by throttle-off. This realizes a driving in which the vehicle gradually decelerates and widens the distance between vehicles without performing braking by the brake as much as possible. As a result, it is possible to create a situation where the merging vehicle 150 can merge smoothly while achieving natural driving also from the perspective of the following vehicle.

[0077] Note that control is performed to allow a temporary congestion of the distance between vehicles with the throttle off without operating the brake as much as possible. However, when the merging vehicle cannot enter without brake control, the minimum target acceleration may be calculated from the relative speed and positional relationship with the merging vehicle 150, the speed and acceleration of the host vehicle 100, etc., and deceleration control may be performed.

[0078] In the embodiment, when recognizing the rear of the merging vehicle 150 as the object of following control, in the following control process for merging, an example is given in which when it is determined from the relative speed and the inter-vehicle distance between the merging vehicle 150 and the host vehicle 100 that deceleration is necessary, the target inter-vehicle distance is changed to a shorter value (see steps S123 and S124 in FIG. 7). In a situation where the rear of the merging vehicle 150 is recognized, it can be estimated that the merging vehicle 150 is in a situation where it starts to merge or is merging. In that case, if the target inter-vehicle distance remains at the normal setting, the distance between the host vehicle 100 and the merging vehicle 150 that enters in front of the host vehicle 100 will be too large. Therefore, by shortening the target inter-vehicle distance, it is possible to prevent the traffic flow from being disrupted due to an overly large inter-vehicle distance.

[0079] In the embodiment, when it is determined that there is a traffic jam, in the following control process for merging, an example is given in which the setting of the target inter-vehicle distance is changed to the setting for traffic jams and the target acceleration is set (see steps S125 and S126 in FIG. 7). During a traffic jam, if the distance between the host vehicle 100 and the merging vehicle 150 is too large, it may disrupt the smooth traffic flow. Therefore, for traffic jams, a shorter inter-vehicle distance is set as the target inter-vehicle distance so that the distance between the merging vehicle 150 and the host vehicle 100 does not become too large, enabling a merging response according to the traffic jam situation.

[0080] In the embodiment, when the acceleration of the merging vehicle as the object of following control is less than a predetermined threshold value and the lap rate with the host vehicle is zero, an example is given in which the process of invalidating the target acceleration obtained for the merging vehicle as the object of following control is performed (see steps S103 and S104 in FIG. 6). The case where the acceleration of the merging vehicle 150 is less than the predetermined threshold value and the lap rate is zero means that the merging vehicle 150 is stopped or decelerating rapidly in the merging lane 301, and it can be estimated that the vehicle does not intend to merge. Therefore, by invalidating the target acceleration obtained for the merging vehicle 150 as the control object, it is possible to avoid the running of the host vehicle 100 being disrupted by a vehicle that does not merge.

[0081] 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.

[0082] In addition, a program for causing a computer device to execute processing as shown in FIGS. 6 and 7 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.

Description of Reference Numerals

[0083] 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 (own vehicle) 150 Merging vehicle 200 Leading vehicle 250 Following vehicle 300 Travel lane 301 Merging lane

Claims

1. A driving control device having a computer device that controls the vehicle to travel at a set vehicle speed or to follow a preceding vehicle, comprising: The computer device includes: A control target setting unit that sets a merging vehicle detected in a merging lane, which is a merging route into the lane in which the host vehicle is traveling, as a following control target; A following control unit that performs a merging-corresponding following process that allows a shorter inter-vehicle distance than the target inter-vehicle distance in a following process that sets a preceding vehicle traveling in the same lane as the host vehicle as a following control target when the merging vehicle is set as the following control target; The lap rate between the merging vehicle set as the following control target and the host vehicle is zero, and When the acceleration of the merging vehicle is less than a predetermined threshold value, or when the target acceleration obtained by setting the merging vehicle as the following control target is less than a predetermined threshold value, Invalidate the target acceleration obtained by setting the merging vehicle as the following control target, and perform a following process that sets a preceding vehicle traveling in the same lane as the host vehicle as the following control target; When the lap rate between the merging vehicle set as the following control target and the host vehicle is zero and the current speed of the merging vehicle is less than a predetermined amount than the speed when it is set as the following control target, perform the following process Driving control device.

2. When the side of the vehicle is recognized for the merging vehicle set as the following control target and the rear of the vehicle is not recognized, In the merging-corresponding following process, the upper limit of the target acceleration is limited to the acceleration by throttle-off. When the rear of the vehicle is recognized for the merging vehicle set as the following control target, In the merging-corresponding following process, when it is determined that deceleration is necessary from the relative speed and the inter-vehicle distance between the merging vehicle and the host vehicle, the target inter-vehicle distance is changed to a shorter value. The driving control device according to claim 1.

3. When it is determined that there is a traffic jam, In the merging-corresponding following process, the setting of the target inter-vehicle distance is changed to a traffic jam setting to set the target acceleration. The driving control device according to claim 1 or claim 2.

Images