VEHICLE SPEED CONTROL DEVICE AND SPEED CONTROL METHOD

Abstract

Vehicle speed control device (10) in which an imaging device (21) for imaging an area in front of a self-propelled vehicle (50) is mounted, wherein the vehicle speed control device comprises: - a boundary line detection device that detects a lane boundary line (61) that defines a self-driving lane (63) that is a lane driven on by the self-driving vehicle, based on an image captured by the imaging device; - a vehicle identification device that performs a lane-entry determination and a lane-out determination with respect to a front vehicle (51) traveling in front of the vehicle itself, wherein the front vehicle traveling on an adjacent lane (64) adjacent to the vehicle itself is determined as a lane-entry vehicle merging into the vehicle itself, and the front vehicle traveling on the vehicle itself is determined as a lane-out vehicle merging out of the vehicle itself, based on a relative position (VL) with respect to a detected boundary line, which is the lane boundary line detected by the boundary line detection device, in a vehicle width direction of the front vehicle; and - a distance determination device that determines whether or not the vehicle in front is within a detection distance range of the detected boundary line, as determined by the boundary line detection device, wherein - the vehicle identification device: - performs the lane-entry and lane-out determinations based on the relative position with respect to the detected boundary line in the vehicle width direction of the vehicle in front, when the distance determination device determines that the vehicle in front is within the detection distance range, and - a first determining device that performs the merging and merging determination based on the relative position with respect to the detected boundary line in the vehicle width direction of the front vehicle, and a second determining device that performs the merging and merging determination based on a relative position with respect to the own vehicle in the vehicle width direction of the front vehicle, and prevents the execution of the merging and merging determination by the second determining device if the distance determining device determines that the front vehicle is within the detection distance area.

Description

[Area of ​​invention]

[0001] The present invention relates to a driving control technology for controlling the driving of a vehicle in which an imaging device is mounted. [State of the art]

[0002] Known as vehicle speed control, a vehicle following control system is one in which a self-driving vehicle follows a selected vehicle ahead. The ahead vehicle is chosen from among vehicles traveling in a dedicated lane that corresponds to the self-driving vehicle's lane. With such a vehicle following control system, it is important to accurately select a vehicle traveling in a dedicated lane from among vehicles detected by a distance sensor, a vehicle-mounted camera, or similar devices. Typically, the process involves calculating a predicted route as a future travel path for the self-driving vehicle and using a vehicle located on that calculated predicted route as the target for the vehicle following control system.For example, JP 2007-331608A discloses the following technique as a method for selecting a leading vehicle as a vehicle-following control target. In the technique according to JP 2007-331608A, a turning circle calculated based on a yaw rate and vehicle speed is used as a predicted route for a leading vehicle. Furthermore, the technique according to JP 2007-331608A calculates a leading-vehicle lane probability, which describes the probability that a leading vehicle is in a leading-vehicle lane, in accordance with an offset distance of a lateral position, which is a position in a lateral direction, between a leading-vehicle lane path and the leading vehicle. In this way, the technique according to JP 2007-331608A selects a leading vehicle to follow in accordance with the calculated leading-vehicle lane probability.

[0003] JP 2007-176483A discloses the following technique. The technique according to JP 2007-176483A calculates a lateral speed, which is a speed in a lateral direction of a lane of a leading vehicle, in order to initiate a lane change by a preceding vehicle at an early stage. Furthermore, the technique according to JP 2007-176483A calculates a predicted lateral position, which is a lateral position of a leading vehicle predicted in accordance with the calculated lateral speed, and the technique according to JP 2007-176483A selects a preceding vehicle to follow based on the calculated predicted lateral position.

[0004] In such a conventional selection procedure, for example, while a vehicle is driving further to the right or further to the left in its own lane, or while a front vehicle driving in an adjacent lane is driving closer to the own lane, there is a risk that a vehicle driving in the adjacent lane will be mistakenly selected as a preceding vehicle and thus as the target of a vehicle following process.

[0005] From DE 10 2009 033 124 A1, a method for determining a lane-change or lane-change maneuver of a vehicle driving ahead of the driver's own vehicle is also known, wherein the driver's own vehicle comprises a driver assistance system serving longitudinal guidance and a camera recording the area in front of the vehicle in the form of two-dimensional images, wherein at least one lane marking delimiting the driver's own lane and at least one image point or image section defined by a vehicle driving ahead are detected in a recorded image, whereupon, taking into account a value representing a measure of the actual distance of the vehicle to the driver's own vehicle, the actual horizontal distance of the distinguished image point or image section to the lane marking is determined, which serves as a measure for determining a lane-change or lane-change maneuver.

[0006] DE 10 2009 007 885 A1 discloses a method for detecting vehicles merging into or out of a vehicle's lane, in which at least one vehicle traveling in the lane adjacent to or ahead of the vehicle in the vehicle's lane is detected by technical means. Based on the detected data, the vehicle's behavior with regard to a possible lane change is automatically assessed.

[0007] From DE 10 2004 013 818 A1, an object location system for motor vehicles is also known, which has a detection device for merging and swerving operations, and DE 11 2006 003 277 T5 teaches a method for detecting or predicting a vehicle merging into a lane. [Brief description of the invention][Objective of the present invention]

[0008] The object of the present invention is to provide a technique for vehicle speed control that can improve the stability of the selection / non-selection of a preceding vehicle as an objective of vehicle following control when a preceding vehicle changes lanes.

[0009] The problem is solved by the subject matter of the independent claims. Advantageous further developments are specified in the dependent claims.

[0010] According to the invention, when the front vehicle changes lanes, it moves in the width direction by crossing the lane boundary line. Consequently, the relative position of the front vehicle with respect to the lane boundary line changes. However, the lane boundary line of the dedicated lane is a stationary object on the road. Therefore, the relative position of the front vehicle with respect to the lane boundary line is defined independently of the position (lateral position) of the vehicle itself in a lateral direction on the dedicated lane. In light of the above points, the speed control device according to the invention is designed to determine whether another vehicle is merging into or out of the lane based on the relative position of the front vehicle with respect to a lane boundary line in the width direction.In particular, the speed control device according to the invention is designed to determine whether a front vehicle traveling in an adjacent lane is a vehicle merging into a dedicated lane (hereinafter also referred to as the merging vehicle), and whether a front vehicle traveling in the dedicated lane is a vehicle merging out of the dedicated lane (hereinafter also referred to as the merging vehicle), based on its relative position with respect to the lane boundary line in the width direction of the front vehicle. Using this configuration, the speed control device according to the invention can determine with high accuracy whether a front vehicle is merging or merging into its lane, even if the dedicated lane is traveling further to the right or left.This means that the speed control device according to the invention can improve the stability of selecting / not selecting a vehicle ahead as a goal of vehicle following control when a vehicle ahead changes lanes. [Brief description of the drawings] Fig. Figure 1 shows a block diagram illustrating a schematic configuration of a vehicle speed control device. Fig. Figure 2 shows an illustration to demonstrate a determination of whether another vehicle is entering or exiting the lane by a first determining device. Fig. Figure 3 shows an illustration to demonstrate the determination of the lane entry and lane exit of another vehicle by a second determining device. Fig. Figure 4 shows a flowchart to illustrate the process of determining the lane entry and lane exit of another vehicle. Fig. Figure 5 shows a flowchart to illustrate the sequence of a first determination process. [Description of the embodiments]

[0011] An embodiment of a vehicle speed control device is described below with reference to the drawings. The speed control device of this embodiment is mounted in a vehicle and performs a vehicle following control, according to which the vehicle travels by following a preceding vehicle traveling in a dedicated lane, which is the same lane as that of the vehicle, under vehicles traveling in front of the vehicle. In the vehicle following control of this embodiment, a following distance is maintained between the vehicle and the preceding vehicle. First, a schematic configuration of the speed control device of this embodiment is shown with reference to the drawings. Fig. 1 described.

[0012] In the Fig. In this embodiment, a cruise control device 10 is a computer comprising a CPU, ROM, RAM, I / O, and the like. The cruise control device 10 includes a white line detection unit 11, a lane-change / lane-out detection unit 12, a vehicle-ahead selection unit 13, and a target value calculation unit 14. The cruise control device 10 implements the aforementioned functions through the CPU, which executes a program installed in the ROM. An object detection device is mounted in the vehicle (own vehicle) to which the cruise control device 10 is attached. This device detects objects in the vicinity of the vehicle. Furthermore, in this embodiment, an imaging device 21 and a radar device 22 are mounted as the object detection device.When information about a detected object is entered by the object detection device, the speed control device 10 performs the vehicle following control with respect to the vehicle ahead on the basis of the entered information.

[0013] The imaging device 21 is a vehicle-mounted camera and consists of a CCD camera, a CMOS sensor, a near-infrared camera, and the like. The imaging device 21 images the vehicle's surroundings (the vehicle's environment), including the roadway, and generates image data of the captured image. The imaging device 21 transmits the generated image data sequentially to the cruise control device 10. For example, the imaging device 21 is installed near the upper edge of the vehicle's windshield and images or captures an area extending in front of the vehicle with an imaging axis as its center point, within a region with a predetermined angle δ1 (capture area of ​​the imaging device 21). Furthermore, the imaging device 21 can be a monocular camera or a stereo camera.

[0014] The radar device 22 is a scanning device that emits electromagnetic waves as transmission waves and detects an object by receiving reflected waves from the transmission waves. Furthermore, in this embodiment, the radar device 22 is constructed from a millimeter-wave radar. The radar device 22 is mounted on the front of the vehicle and scans an area (detection area of ​​the radar device 22) extending in front of the vehicle with a light axis as its center within a region with a predetermined radar angle δ2 (δ2 < δ1), using a radar signal. The radar device 22 generates distance measurement data of the detected object based on the time from the transmission of the electromagnetic waves from the vehicle forward until the reception of the reflected waves. The radar device 22 sequentially transmits the generated distance measurement data to the cruise control device 10.The distance measurement data contains information about the direction in which the object is located relative to the vehicle, the distance from the vehicle to the object, and the relative speed of the object relative to the vehicle.

[0015] In the imaging device 21 and the radar device 22, the imaging axis, which is a reference axis of the imaging device 21, and the light axis, which is a reference axis of the radar device 22, are such that they run in a direction that is parallel to a road surface of the road traveled by the vehicle. A detection range (detectable range) of the imaging device 21 and a detection range (detectable range) of the radar device 22 partially overlap.

[0016] The cruise control device 10 receives inputs of image data from the imaging device 21 and distance measurement data from the radar device 22. Furthermore, the cruise control device 10 receives inputs of detection signals from various types of sensors provided in the vehicle. These other types of sensors include a yaw rate sensor 23, a vehicle speed sensor 24, a steering angle sensor 25, and an ACC switch 26, among others. The yaw rate sensor 23 detects the angular velocity (yaw rate) with respect to the vehicle's direction of rotation. The vehicle speed sensor 24 detects the vehicle's speed. The steering angle sensor 25 detects the vehicle's steering angle. The ACC switch 26 is an input switch for selecting permission to execute a vehicle following control mode.

[0017] The speed control device 10 comprises the white line detection unit 11, the lane-change / lane-out determination unit 12, the vehicle-ahead selection unit 13, and the control target value processing unit 14. The white line detection unit 11 serves as a boundary line detection device that recognizes a white line on a road surface as a lane boundary line defining a dedicated lane, which is the lane occupied by the vehicle. In this embodiment, the white line is detected as follows: The white line detection unit 11 receives image data inputs from the imaging device 21 and extracts edge points as white line candidates from the input image data based on the rate of change or similar characteristic of the luminance in a transverse direction of the input image.The white line detection unit 11 sequentially stores the extracted edge points for each frame and detects a white line based on a dataset of the stored edge points. The white line detection unit 11 stores the detection result as white line information (information about the detected lane boundary line).

[0018] The merging / exit detection unit 12 serves as a vehicle detection device that identifies a merging vehicle entering its own lane (the lane it is traveling in) and an exiting vehicle exiting its own lane among the objects detected by the object detection device. In short, the merging / exit detection unit 12 corresponds to a merging detection function and an exit detection function with respect to another vehicle. For simplicity, an object detected by the object detection device is hereinafter also referred to as a "target".The lane-change / lane-out detection unit 12 of this embodiment performs a fusion of data from a target detected by the imaging device 21 and a target detected by the radar device 22, both belonging to the same object (image data and distance measurement data containing a target belonging to the same object). The lane-change / lane-out detection unit 12 determines the presence or absence of a leading vehicle, targeting a fusion target obtained by fusion. If the presence of a leading vehicle is determined, the lane-change / lane-out detection unit 12 performs lane-change and lane-out detection of the other vehicle.According to an example of data fusion, with respect to image data and distance measurement data, multiple detection points present within a predetermined fusion area are fused as data belonging to the same object. If the target detected by the imaging device 21 and the target detected by the radar device 22 have a predetermined positional ratio, the data fusion is performed under the assumption that the image data and the distance measurement data belong to the same object, corresponding to the detected target. It should be noted that the data fusion procedure is not limited to this.

[0019] The lead vehicle selection unit 13 selects (or deselects) a lead vehicle, which will be the target of a vehicle following process, from among the objects detected by the object detection device, based on the determination result of the merging / exiting of the other vehicle by the merging / exiting determination unit 12. In the speed control device 10 of this embodiment, a base image in which a lane probability is defined, indicating the probability that a lead vehicle is present in the lane, which is the lane traveled by the lead vehicle, is stored in advance in accordance with an offset position (hereinafter referred to as the "lateral offset position"), which is a relative position with respect to a lead vehicle in a vehicle width direction (lateral direction) of the lead vehicle.In short, the cruise control device 10 stores map data in a predetermined memory area (such as a memory location) in which an offset position in the lateral direction of the leading vehicle and the probability of its own lane are linked in advance. The leading vehicle selector 13 reads the probability of its own lane, corresponding to an offset position in the lateral direction of the leading vehicle, from the data of the base map and corrects the probability of its own lane in accordance with the determination result of the lane-change determination unit 12. The leading vehicle selector 13 selects a leading vehicle for which the corrected probability of its own lane is greater than or equal to a predetermined value as a leading vehicle for the vehicle following control.Otherwise, with respect to a leading vehicle where the probability of following its own lane is below a predetermined value, the selection as the leading vehicle for the vehicle following control is deleted. Regarding the offset position in the lateral direction of the leading vehicle, the offset position is obtained, for example, by correcting a position coordinate in the vehicle width direction (lateral direction), which is detected by the imaging device 21, based on an estimate R that describes a curve radius of a predicted route (curve) in the leading vehicle. Furthermore, in this embodiment, a mid-position in the lateral direction of a target corresponding to the leading vehicle is used as an offset position in the lateral direction of the leading vehicle.

[0020] The speed control device 10 of this embodiment controls the vehicle speed (driving speed) of the vehicle in order to maintain a predetermined target distance (interval) between the vehicle ahead, selected by the vehicle ahead selector unit 13, and the vehicle itself. The target value control unit 14 calculates a target value for executing such vehicle speed control. In particular, the target value control unit 14 calculates a target output power, a required braking force, and the like for the vehicle's internal combustion engine and outputs the calculated control value as a control signal to the electronic internal combustion engine control unit (ECU) 31.The cruise control device 10 of this embodiment is designed to output a control signal to the internal combustion engine ECU 31, which in turn outputs the control signal to the electronic brake control unit (brake ECU) 32. It should be noted that the output configuration of a control signal is not limited to this. The cruise control device 10 can, for example, be designed to output the control signal to both the internal combustion engine ECU 31 and the brake ECU 32.

[0021] The following describes in more detail the determination of whether another vehicle is merging into or out of a lane according to this embodiment. The merging / out-determining unit 12 performs several determination processes in which the determination parameters used to determine whether a front vehicle is merging into or out of a lane with respect to its own lane, which is the lane being traveled, are each different from one another. In particular, the merging / out-determining unit 12 has a first determination device that determines whether a front vehicle is merging into or out of a lane based on its relative position with respect to a white line detected by the white-line detection unit 11 (detected boundary line) in the vehicle width direction (transverse direction).Furthermore, the lane-change / lane-out determination unit 12 has a second determination device that determines lane-change and lane-out based on a relative position with respect to the vehicle's own width (transverse direction) of a preceding vehicle. The lane-change / lane determination unit 12 performs the lane-change determination and lane-out determination of another vehicle (first determination process) by the first determination device or the lane-change determination and lane-out determination of another vehicle (second determination process) by the second determination device in accordance with the fulfillment or non-fulfillment of a predetermined execution condition.

[0022] First, the lane-entry and lane-out determinations of the other vehicle are to be carried out using the first determining device with reference to the Fig. 2 described. Fig. Figure 2 shows a case in which a front vehicle 51 is present within a range of a detected distance in the transverse direction of a white line 61 (a detection distance in the transverse direction of a boundary line detected by the white line detection unit 11) which is detected by an imaging device 21 which is mounted in the own vehicle 50. Fig. Figure 2 shows an example where the imaging device 21 detects a white line 61a on the right side and a white line 61b on the left side with respect to a direction of travel of the own vehicle 50.

[0023] The front vehicle 51, which is traveling in an adjacent lane 64 next to a dedicated lane 63, can change lanes onto the dedicated lane 63 and merge in front of the dedicated vehicle 50. In this case, the front vehicle 51 approaches as described in Fig. As shown in Figure 2(A), the white line 61a is on the right-hand side with respect to the direction of travel of the vehicle 50, and the leading vehicle 51 finally crosses the white line 61a. That is, the leading vehicle 51 moves from the adjacent lane 64 to the dedicated lane 63. Furthermore, for example, the leading vehicle 51, which is traveling in the same lane as the vehicle 50 (dedicated lane 63), can change lanes to the adjacent lane 64 and pull out of the dedicated lane 63. In this case, the leading vehicle 51 approaches, as shown in Figure 2(A). Fig. As shown in Figure 2(B), the white line 61a is on the right-hand side with respect to the direction of travel of the vehicle 50, and the vehicle 51 leading the front finally crosses the white line 61a. That is, the vehicle 51 leading the front moves from its own lane 63 to the adjacent lane 64. In short, when the vehicle 51 leading the front changes lanes, it crosses the white line 61a and moves in a transverse direction (direction of the arrow), which is a vehicle width direction. In this way, the relative position with respect to the white line 61 changes in the vehicle width direction (transverse direction) of the vehicle 51 leading the front.

[0024] Taking these circumstances into account, the merging and exiting determination of the other vehicle by the first determining device uses a relative position with respect to the white line 61 in the vehicle width direction (transverse direction) of the front vehicle 51 to determine the merging into and exiting from the dedicated lane 63 of the front vehicle 51. In particular, in this embodiment, the merging and exiting determination of another vehicle is based on a change amount and a sign of the change amount (direction of change) at the relative position with respect to the white line 61 in the vehicle width direction (transverse direction) of the front vehicle 51.

[0025] In particular, the lane-change determination unit 12 performs the following initial determination process. The lane-change determination unit 12 calculates a white-line crossing amount VL, which indicates the degree to which the leading vehicle 51 crosses the white line 61, as a parameter that indicates the relative position of the leading vehicle 51 with respect to the white line 61 in the vehicle width direction (transverse direction). The lane-change determination unit 12 then performs the lane-change determination and the lane-change determination of another vehicle based on the calculated white-line crossing amount VL. The term "crossing amount" here describes the degree to which a vehicle crosses the white line 61, more precisely, the degree to which the vehicle merges or enters the other lane after crossing the white line 61.

[0026] The white-line crossing amount VL of this embodiment is described in more detail below. As in Fig. As shown in Figure 2, the white line crossing amount VL is the amount by which the front vehicle 51 crosses the white line 61a. In the Fig. 2 is shown as VL as a distance from a left side to the white line 61a in a transverse direction in the direction of travel of the front vehicle 51. Furthermore, according to the definition mentioned above, the value of the white-line crossing amount VL takes on a value of zero in a state in which the left side of the front vehicle 51 is on the white line 61a and is approaching the white line 61a maximally, and then a positive value when the front vehicle 51 crosses the white line 61a by moving in the transverse direction. In this way, as in Fig. 2 (A) shows the merge / exit determination unit 12 that the front vehicle 51 is a vehicle merging into the dedicated lane 63 when a time series change amount of the white line crossing amount VL is a positive value (a change amount ΔVL per unit time is a positive value) and the white line crossing amount VL is above a first threshold TH1.

[0027] In a case where the leading vehicle 51 moves to the adjacent lane 64 by changing lanes from the lane of its own vehicle 50 (own lane 63), VL assumes a negative value if the leading vehicle 51 crosses the white line 61a by moving laterally. In this way, the lane-change determination unit 12 determines, as in Fig. 2(B) showed that the front vehicle 51 is a vehicle pulling out of its own lane 63 if the time series change amount of the white line crossing amount VL has a negative value (a change amount ΔVL per unit time is a negative value) and the white line crossing amount VL is below a second threshold TH2.

[0028] The following are the determination of the other vehicle's lane entry and lane exit by the second determining device with reference to the Fig. 3 described. Fig. Figure 3 shows a case in which the front vehicle 51 is outside the area of ​​the detected distance in the transverse direction of the white line 61 according to a detection by the imaging device 21 (a detection distance of a detected boundary line by the white line detection unit 11) and the relative position with respect to the white line 61 in the vehicle width direction (transverse direction) of the front vehicle 51 cannot be used.

[0029] The determination of the other vehicle's entry and exit by the second determination device corresponds to a second determination process for performing an entry and exit determination using a relative position in the vehicle width direction (transverse direction) of the front vehicle 51, which has been calculated with respect to the own vehicle 50 as a determination parameter. The entry / exit determination unit 12 performs the following second determination process. The entry / exit determination unit 12 calculates an offset position (offset position in the transverse direction) Rx, which is a position coordinate based on the own vehicle 50 in the x-axis direction of the front vehicle 51, based on an orthogonal coordinate system in which a vehicle width direction (transverse direction) of a vehicle is used as an x-axis and a vehicle's direction of travel is used as a y-axis.Furthermore, according to this embodiment, on the x-axis, the right side is defined as positive with respect to the direction of travel of the vehicle 50 and the left side as negative. The lane-change / lane-out determination unit 12 performs the lane-change determination and the lane-out determination of another vehicle based on the calculated offset position (offset position in the transverse direction of the front vehicle 51) Rx and a transverse speed (speed in the transverse direction of the front vehicle 51) Vf, which is obtained by a time derivative of the offset position Rx.

[0030] In particular, the reeving / removal determination unit 12 determines, as in Fig. 3(A) shows that the leading vehicle 51 is a lane-change vehicle if the sign of the offset position Rx in the transverse direction of the leading vehicle 51 and the sign of the transverse velocity Vf of the leading vehicle 51 are different, and the transverse velocity Vf is greater than or equal to a threshold value and the offset position Rx is below a threshold value. Furthermore, the lane-change / lane-out determination unit 12, as shown in Fig. 3(B) shown that the leading vehicle 51 is a drifting vehicle if the sign of the offset position Rx in the transverse direction of the leading vehicle 51 and the sign of the transverse velocity Vf of the leading vehicle 51 are the same and the transverse velocity Vf is greater than or equal to a threshold and the offset position Rx is greater than or equal to a threshold.

[0031] The lane-change / lane-out determination unit 12 determines a first condition that the driving state of the vehicle 50 is stable with respect to the white line 61, and performs the lane-change determination and the lane-out determination of another vehicle under the condition that the first condition is met. In this embodiment, the following three subconditions are included as the first condition. (I) A position in the transverse direction of the own vehicle 50 on the own lane 63 can be obtained from the white line information. (II) The lateral speed Vf of the leading vehicle 51 can be calculated. In short, the discontinuous lateral movement width of the own vehicle 50 is less than or equal to a predetermined value. (III) A travel amount in the transverse direction of the own vehicle 50 is less than or equal to a threshold value, and a state in which the travel amount is less than or equal to the threshold value lasts for a predetermined time.

[0032] The lane-change / lane-out determination unit 12 serves as a state determination device that determines that the driving state of the own vehicle 50 is stable with respect to the white line 61 when these three sub-conditions are met and thus the first condition is met.

[0033] The lane-change / lane-out detection unit 12 of this embodiment preferably performs the lane-change and lane-out detection of the other vehicle by means of the first detection device located between the first detection device and the second detection device. In particular, the lane-change / lane-out detection unit 12 serves as a distance detection device that determines whether or not the front vehicle 51, which is detected by the object detection device, is present within a detection distance range in the transverse direction of the white line 61, which is detected by the white line detection unit 11. If it is determined that the front vehicle 51 is present within the detection distance range of the white line 61, the lane-change / lane-out detection unit 12 prevents the second detection device from performing the lane-change and lane-out detection of the other vehicle.In short, when a white line is detected, the selection of a lane-entering and lane-departing vehicle using the offset position Rx in the transverse direction of the leading vehicle 51 as a determination parameter is prevented. This is because lane-entering and lane-departing determination of another vehicle using the white line 61 is possible if the leading vehicle 51 is within the detection range of the white line 61. Otherwise, if it is determined that the leading vehicle 51 is outside the detection range of the white line 61, the lane-entering / lane-departing unit 12 performs lane-entering and lane-departing determination of the other vehicle using the second determination device.This is because the lane-change and lane-change determination of the other vehicle using the white line 61 is not possible if the leading vehicle 51 is outside the detection range of the white line 61. The lane-change / lane-change determination unit 12, as described above, determines a second condition that the leading vehicle 51 is within the detection range of the white line 61, and performs the lane-change and lane-change determination of the other vehicle subject to the condition that the second condition is met.

[0034] The following is the lane-closing and lane-out determination process of another vehicle, which is implemented in the speed control device 10 of this embodiment, with reference to the information in the Fig. 4 and Fig. The flowcharts shown in the 5 diagrams are described. First, a process is described in the Fig. The main routine shown in Figure 4 is described. This process is carried out in a specific cycle by the lane-change / lane-out control unit 12, which is provided in the speed control device 10, when the ACC switch 26 is turned on (when a vehicle following control mode is in operation).

[0035] As in Fig. As shown in Figure 4, the lane-change determination unit 12 determines whether or not the front vehicle 51 has been detected by the object detection device (step S100). In a process within step S100, the presence or absence of the front vehicle 51 is determined with respect to a fusion target. Furthermore, if multiple front vehicles 51 are present, one vehicle is selected as the target from among the multiple front vehicles 51. This results in the lane-change determination unit 12 terminating this routine if it is determined that a front vehicle 51 has not been detected (that the front vehicle 51 is not present) (step S100: NO). Otherwise, if it is determined that the front vehicle 51 has been detected (that the front vehicle 51 is present) (step S100: YES), the lane-change determination unit 12 proceeds to step S101.The reeving / re-ejection determination unit 12 acquires white line information calculated on the basis of the image data from the imaging device 21 from the white line detection unit 11 (step S101).

[0036] The lane-change determination unit 12 then determines whether the driving state of the vehicle 50 is stable with respect to the white line 61, based on the result of the fulfillment of the first condition (step S102). This means that if it is determined that the first condition is not fulfilled and the driving state of the vehicle 50 is not stable with respect to the white line 61 (step S102: NO), the lane-change determination unit 12 terminates this routine. Otherwise, if it is determined that the first condition is fulfilled and the driving state of the vehicle 50 is stable with respect to the white line 61 (step S102: YES), the lane-change determination unit 12 proceeds to step S103 and determines the second condition.The lane-change / lane-out determination unit 12 determines whether or not the front vehicle 51, detected by the object detection device, is within the detection range of the white line 61, which is detected based on the white line information (step S103). Furthermore, in the process of step S101, the lane-change / lane-out determination unit 12 performs the determination of the second condition using the image data from the imaging device 21, which is acquired together with the white line information from the white line detection unit 11.

[0037] This means that if it is determined that the front vehicle 51 is within the detection distance of the white line 61 (step S103: YES), the lane-change / lane-out determination unit 12 proceeds to step S104. That is, if the first and second conditions are met, the lane-change / lane determination unit 12 proceeds to step S104. The lane-change / lane determination unit 12 performs the lane-change and lane-out determination of the other vehicle using the first determination device (step S104). Simultaneously with this step, the lane-change / lane determination unit 12 prevents the lane-change and lane-out determination of the other vehicle by the second determination device.Otherwise, if it is determined that the front vehicle 51 is not within the detection range of the white line 61 (is outside the detection range) (step S103: NO), the lane-change determination unit 12 proceeds to step S105. That is, if the first condition is met and the second condition is not met, the lane-change determination unit 12 proceeds to step S105. The lane-change determination unit 12 performs the lane-change determination and the lane-change determination of the other vehicle using the second determination device (step S105).

[0038] The following are the determination of the other vehicle's lane entry and lane exit by the first determining device (the first determination process of the aforementioned step S104) with reference to the Fig. 5 described. As in Fig. As shown in Figure 5, the lane-change / lane-out determination unit 12 calculates the white-line crossing amount VL, which indicates the degree to which the front vehicle 51 crosses the white line 61, using the image data from the imaging device 21 acquired by the white-line detection unit 11 (step S201). In this embodiment, the white-line crossing amount VL is calculated using the following equation (1) using, for example, a vehicle width CW of the front vehicle 51 and a distance LA between a vehicle centerline of the front vehicle 51 and the white line 61. VL=CW / 2−LA

[0039] Furthermore, the distance LA is a value that can be detected from the image data of the imaging device 21 and is used, in the process of step S201, as a detected distance between the white line 61a, which is to be crossed by the front vehicle 51 when changing lanes, and the vehicle center axis.

[0040] The merging / exiting determination unit 12 then determines whether the white line crossing amount VL increases and whether the white line crossing amount VL exceeds the first threshold TH1 (step S202). Furthermore, the merging / exiting determination unit 12 determines that the white line crossing amount VL increases by applying a change amount ΔVL per unit time of the white line crossing amount VL, and makes a positive determination if ΔVL is a positive value (if ΔVL > 0). In this embodiment, a positive value has also been set as the first threshold TH1 to detect a condition in which the leading vehicle 51 crosses the white line 61a provided between the dedicated lane 63 and the adjacent lane 64.

[0041] This means that when the white line crossing amount VL increases (ΔVL > 0) and exceeds the first threshold TH1 (VL > TH1) (step S202: YES), the lane-crossing determination unit 12 advances to step S203. The lane-crossing determination unit 12 determines that the leading vehicle 51 is a lane-crossing vehicle (step S203). Furthermore, in step S202, it can be determined that the rate of change ΔVL of the white line crossing amount VL increases by determining whether or not an increase per unit time of the white line crossing amount VL is greater than or equal to a predetermined amount.

[0042] Otherwise, if the white line crossing amount VL does not increase (ΔVL ≤ 0) or the white line crossing amount VL is less than or equal to the first threshold TH1 (VL ≤ TH1) (step S202: NO), the reefing / exiting determination unit 12 advances to step S204. The reefing / exiting determination unit 12 determines whether or not the white line crossing amount VL decreases and whether the white line crossing amount VL is below the second threshold TH2 (step S204). Furthermore, the retardation / decision unit 12 determines that the white line crossing amount VL decreases by using a change amount ΔVL per unit time of the white line crossing amount VL, and the retardation / decision unit 12 makes a positive determination when ΔVL is a negative value (when ΔVL < 0).Furthermore, in this embodiment, a positive value has been set as the second threshold TH2 to detect a condition in which the front vehicle 51 crosses the white line 61a, which is provided between the dedicated lane 63 and the adjacent lane 64. Furthermore, the first threshold TH1 and the second threshold TH2 can be the same or different from each other.

[0043] This means that if the white line crossing amount VL does not decrease (ΔVL ≥ 0) or the white line crossing amount VL is greater than or equal to the second threshold TH2 (VL ≥ TH2) (Step S204: NO), the merge / exit determination unit 12 terminates this routine. Otherwise, if the white line crossing amount VL decreases (ΔVL < 0) and the white line crossing amount VL is below the second threshold (VL < TH2) (Step S204: YES), the merge / exit determination unit 12 proceeds to step S205. The merge / exit determination unit 12 determines that the leading vehicle 51 is an exiting vehicle (Step S205). Furthermore, in step S204, it can be determined that the change amount ΔVL of the white line crossing amount VL decreases by determining whether or not a decrease amount per unit time of the white line crossing amount VL is greater than or equal to a predetermined amount.

[0044] The speed control device 10 of this embodiment can produce the following advantageous effect, as described in more detail above.

[0045] The speed control device 10 of this embodiment is designed to perform the lane-entry and lane-out determination based on the relative position of the front vehicle 51 with respect to the white line 61 in the vehicle width direction (transverse direction), which is the lane boundary line of the dedicated lane 63. In particular, the device 10 is designed to determine that the front vehicle 51, which is traveling in the adjacent lane 64, is a lane-entry vehicle into the dedicated lane 63, and to determine that the front vehicle 51, which is traveling in the dedicated lane 63, is a lane-out vehicle from the dedicated lane 63. According to this configuration, in the speed control device 10 of this embodiment, the lane-entry and lane-out determination of the front vehicle 51 can be performed with high accuracy, even if the dedicated lane 63 is traveling further to the right or further to the left.This leads to an improvement in the stability of the selection / non-selection of a preceding vehicle, which will be a target in a vehicle following control, in the speed control device 10 of this embodiment when the front vehicle 51 changes lanes.

[0046] The speed control device 10 of this embodiment is designed to perform the lane-change determination and the lane-out determination based on the magnitude and sign of the change (direction of change) at a relative position with respect to the white line 61 in the vehicle width direction (transverse direction) of the leading vehicle 51. The direction of change of the aforementioned relative position differs between a case in which the leading vehicle 51 lanes from the adjacent lane 64 onto its own lane 63 and a case in which the leading vehicle 51 lanes from its own lane 63 onto the adjacent lane 64. Furthermore, the magnitude of change of the aforementioned relative position can be used to determine the degree (amount) of crossing of the white line 61 by the leading vehicle 51.In view of this fact, the accuracy in determining whether the front vehicle 51 is a lane-entering vehicle or a lane-out vehicle can be improved in the speed control device 10 of this embodiment using the configuration described above.

[0047] The speed control device 10 of this embodiment is designed to perform lane-entry and lane-out determination based on the relative position with respect to the white line 61 in the vehicle width direction (transverse direction) of the front vehicle 51, provided that the front vehicle 51 is determined to be within the detection distance of the white line 61. That is, the speed control device 10 of this embodiment is designed to perform a determination process based on the relative position with respect to the white line 61 in the vehicle width direction (transverse direction) of the front vehicle 51 only if lane-entry and lane-out determination using the white line 61 is possible.According to this configuration, in the speed control device 10 of this embodiment, an incorrect determination during the merging determination and during the merging determination of another vehicle can be prevented.

[0048] The speed control device 10 of this embodiment is designed to perform the lane-entry and lane-out determination (determination process by the first determining device) based on the relative position with respect to the white line 61 in the vehicle width direction (transverse direction) of the front vehicle 51 when it is determined that the front vehicle 51 is within the detection distance of the white line 61. In this case, the speed control device 10 of this embodiment is designed to prevent the lane-entry and lane-out determination (the execution of the determination process by the second determining device) based on a relative position with respect to the vehicle 50 in the vehicle width direction (transverse direction) of the front vehicle 51.The speed control device 10 of this embodiment is designed to preferably execute the determination process by the first determination device before the second determination device when it is determined that the front vehicle 51 is within the detection range of the white line 61. For example, when the second determination device determines whether the other vehicle is merging or changing lanes, there is a risk that the front vehicle 51, which is traveling in the adjacent lane 64, will be identified as merging. Consequently, the determination process by the second determination device has a lower degree of accuracy than the determination of whether the other vehicle is merging or changing lanes by the first determination device.Accordingly, based on the configuration described above, the speed control device 10 of this embodiment can improve the accuracy of determining the lane-entry and lane-out determination of another vehicle to the greatest extent possible.

[0049] The speed control device 10 of this embodiment is designed to perform the lane-change and lane-change determination of the other vehicle by the second determining device when it is determined that the front vehicle 51 is outside the detection distance of the white line 61. In a situation where lane-change and lane-change determination (the determination by the first determining device) cannot be performed based on the relative position with respect to the white line 61 in the width direction (transverse direction) of the front vehicle 51, lane-change and lane-change determination of another vehicle are performed by a different determining device (by the second determining device).Based on this configuration, the speed control device 10 of this embodiment can maximally improve the response to a change in the selection / non-selection of a preceding vehicle that will be a target in a vehicle following control.

[0050] The speed control device 10 of this embodiment uses the white-line crossing amount VL, which describes the degree to which the front vehicle 51 has crossed the white line 61, as the parameter indicating the relative position of the front vehicle 51 with respect to the white line 61 in the vehicle width direction (transverse direction). Furthermore, the speed control device 10 of this embodiment is designed to perform the lane-change determination and lane-change determination of another vehicle based on the white-line crossing amount VL. Using this configuration, the speed control device 10 of this embodiment can immediately detect with high accuracy that the lane change has been initiated by the front vehicle 51, based on the degree to which the front vehicle 51 has crossed the white line 61.This means that the speed control device 10 of this embodiment can improve the stability of the and the response to the selection / non-selection of a preceding vehicle, which will be a target in a vehicle following control.

[0051] The speed control device 10 of this embodiment is designed to perform the lane-change and lane-change determination based on the relative position with respect to the white line 61 in the transverse direction of the front vehicle 51, provided that the driving state of the own vehicle 50 is determined to be stable with respect to the white line 61. In a case where the driving state of the own vehicle 50 is unstable with respect to the white line 61, such as when the own vehicle 50 intends to change lanes or when the own vehicle 50 is oscillating, it is very likely that the lane-change and lane-change determination of the front vehicle 51 will be incorrect (highly likely to be incorrectly determined).In view of this fact, the speed control device 10 of this embodiment, based on the configuration described above, can prevent a decrease in accuracy in determining the merging and merging of another vehicle.

[0052] The speed control device 10 of this embodiment uses the white-line crossing amount VL, which describes the degree to which the front vehicle 51 has crossed the white line 61, as the parameter indicating the relative position of the front vehicle 51 with respect to the white line 61 in the vehicle width direction (transverse direction). Furthermore, the speed control device 10 of this embodiment is designed to perform the lane-change determination and lane-out determination of the other vehicle based on the white-line crossing amount VL. In addition, a situation is assumed in which the front vehicle 51, traveling in the adjacent lane 64, moves closer to its own lane 63. In such a case, it is assumed that the front vehicle 51, traveling in the adjacent lane 64, may be erroneously identified as a preceding vehicle that will be the target of a vehicle following control.In light of this fact, and based on the configuration described above, the cruise control device 10 of this embodiment can immediately detect with high accuracy that the lane change was initiated by the vehicle 51 ahead by using the degree to which the vehicle 51 has crossed the white line 61. This allows the cruise control device 10 of this embodiment to improve the stability of the vehicle and its response to the selection / non-selection of a vehicle ahead as a target of vehicle following control. (Other embodiments)

[0053] The speed control device 10 of the present invention is not limited to the embodiment described above, but can be implemented, for example, as follows.

[0054] In the embodiment described above, the white-line crossing amount VL is calculated as the degree to which the front vehicle 51 crosses the white line 61. This parameter indicates the relative position of the front vehicle 51 relative to the white line 61 in the vehicle width direction (transverse direction). Furthermore, in the embodiment described above, the merging and merging of the other vehicle are determined using the calculated white-line crossing amount VL. However, the determination parameter is not limited to the white-line crossing amount VL. For example, other embodiments may be designed to calculate a position coordinate relative to the white line 61 in the vehicle width direction (transverse direction) of the front vehicle 51 and to perform the merging and merging of another vehicle based on this calculated position coordinate.

[0055] In the embodiment described above, the extent to which the front vehicle 51 crosses the white line 61 is used as the white line crossing amount VL; however, the manner in which the degree of crossing of the white line 61a by the front vehicle 51 is indicated is not limited to this. In further embodiments, a distance between the side surface of the front vehicle 51 and the white line 61a can be defined as XL, and the ratio of a distance XL to a lane width WL of a traffic lane (XL / WL) can be defined as the white line crossing amount VL. Furthermore, the white line crossing amount VL can be a distance from the vehicle centerline of the front vehicle 51 to the white line 61a.Alternatively, the white line crossing amount VL can be not the amount of a crossing of the own lane 63 travelled by the own vehicle 50, but an amount of a crossing of the adjacent lane 64 by the front vehicle 51.

[0056] In the embodiment described above, the white-line crossing amount VL is calculated using the white line 61a, which the front vehicle 51 is to cross, as a reference line, but the calculation is not limited to this. In further embodiments, the white-line crossing amount VL can be calculated using the white line 61b as a reference line, which differs from the white line 61a to be crossed by the front vehicle 51, between the right and left white lines 61 that describe the lane boundaries of the dedicated lane 63.

[0057] In the embodiment described above, the first determining device determines whether the front vehicle 51 is a merging vehicle or a merging vehicle when determining whether the other vehicle is merging or merging, based on the white-line crossing amount VL, which describes the extent to which the front vehicle 51 crosses the white line 61 (degree of crossing). However, the present configuration is not limited to this. In further embodiments, for example, it can be determined whether the front vehicle 51 is a merging vehicle or a merging vehicle based on the extent to which it approaches the white line 61.In further embodiments, in a state where the front vehicle 51 is approaching the lane 63 occupied by the self-propelled vehicle 50, the determination of whether the vehicle is merging into or out of the lane is based on a distance ZL from the side surface of the front vehicle 51 in the transverse direction to the white line 61a. In this case, in further embodiments, a direction in which the front vehicle 51 moves towards the lane 63 is defined as positive and a direction in which the front vehicle 51 moves away from the lane 63 is defined as negative at a positional coordinate in the transverse direction. In this way, when the front vehicle 51 merges into or drives onto the lane 63, the distance ZL is described by a positive value, and then when the front vehicle 51 leaves the lane 63, the distance ZL is described by a negative value.In further embodiments, when an approximation degree is used, the distance ZL in the transverse direction from the side surface of the front vehicle 51 to the white line 61a, as described above, is compared with a predetermined threshold value and, based on the comparison result, it is determined whether the front vehicle 51 is a merging or a merging vehicle.

[0058] In the embodiment described above, the lane-change / lane-out determination unit 12 comprises the first determination device and the second determination device. Furthermore, in the embodiment described above, the determination by the first determination device or the determination by the second determination device is carried out in accordance with the fulfillment or non-fulfillment of a predetermined operating condition. However, the present configuration is not limited to this. The lane-change / lane-out determination unit 12 according to further embodiments can be configured to comprise only the first determination device and to perform the lane-change and lane-out determination of a different vehicle.

[0059] In the embodiment described above, if the front vehicle 51 is outside the detection range of the white line 61 (further away than the detection range), the lane-entry and lane-out determinations of the other vehicle are performed by the second determination device. However, the present configuration is not limited to this. In further embodiments, the processing of the lane-entry and lane-out determinations of another vehicle may not be carried out at all (a configuration to prevent the determination from being carried out). In particular, if a negative determination occurs in the process of step S103 in the Fig. 4. The processing of step S105 may not be carried out, and this routine can be terminated.

[0060] In the embodiment described above, if it is determined that the driving state of the vehicle 50 is unstable with respect to the white line 61, the lane-entry and lane-out determinations of another vehicle are not executed (a configuration to prevent the execution of the determination). However, the present configuration is not limited to this. For example, other embodiments may be designed to execute the lane-entry and lane-out determinations of the other vehicle using the second determination device.

[0061] In the embodiment described above, a state in which the driving state of the vehicle 50 is stable with respect to the white line 61 is defined as the first condition, and the merging and merging determinations of another vehicle are performed under the condition that the first condition is met. In the embodiment described above, if all three sub-conditions (I)-(III) describing the first condition are met, the driving state of the vehicle 50 is determined to be stable with respect to the white line 61. However, the present configuration is not limited to this. In further embodiments, if at least two of the three sub-conditions (I)-(III) mentioned above are met, it can be determined that the first condition is met.In further embodiments, if at least one of the three aforementioned subconditions (I)-(III) is satisfied, it can be determined that the first condition is satisfied.

[0062] In the embodiment described above, the lane-entry and lane-out detection of another vehicle is performed by targeting a fusion target. However, the present configuration is not limited to this. Other embodiments may, for example, be designed to perform the lane-entry and lane-out detection of another vehicle either by targeting the target detected by the imaging device 21 or the target detected by the radar device 22.

[0063] In the embodiment described above, the imaging device 21 and the radar device 22 are provided as the object detection device. However, the present configuration is not limited to this. In further embodiments, for example, a sonar for detecting an object using ultrasonic waves for the transmission waves can be provided as an alternative to the radar device 22. Furthermore, in other embodiments, the technology according to the invention can be applied to a system in which only the imaging device 21 is provided as the object detection device. [List of reference symbols] 10 Speed ​​control device 11 White line detection unit 12 Shearing / Shearing Determination Unit 13 Leading vehicle selector unit 14 Control target value calculation unit 21 Imaging device 22 Radar device 23 Yaw rate sensor 31 Internal combustion engine ECU 32 Brake ECU

Claims

[1] Vehicle speed control device (10) in which an imaging device (21) for imaging an area in front of a self-propelled vehicle (50) is mounted, wherein the vehicle speed control device comprises: - a boundary line detection device that detects a lane boundary line (61) that defines a self-driving lane (63) that is a lane driven on by the self-driving vehicle, based on an image captured by the imaging device; - a vehicle identification device that performs a lane-entry determination and a lane-out determination with respect to a front vehicle (51) traveling in front of the vehicle itself, wherein the front vehicle traveling on an adjacent lane (64) adjacent to the vehicle itself is determined as a lane-entry vehicle merging into the vehicle itself, and the front vehicle traveling on the vehicle itself is determined as a lane-out vehicle merging out of the vehicle itself, based on a relative position (VL) with respect to a detected boundary line, which is the lane boundary line detected by the boundary line detection device, in a vehicle width direction of the front vehicle; and - a distance determination device that determines whether or not the vehicle in front is within a detection distance range of the detected boundary line, as determined by the boundary line detection device, wherein - the vehicle identification device: - performs the lane-entry and lane-out determinations based on the relative position with respect to the detected boundary line in the vehicle width direction of the vehicle in front, when the distance determination device determines that the vehicle in front is within the detection distance range, and - a first determining device that performs the merging and merging determination based on the relative position with respect to the detected boundary line in the vehicle width direction of the front vehicle, and a second determining device that performs the merging and merging determination based on a relative position with respect to the own vehicle in the vehicle width direction of the front vehicle, and prevents the execution of the merging and merging determination by the second determining device if the distance determining device determines that the front vehicle is within the detection distance area. [2] Vehicle speed control device according to claim 1, wherein the vehicle determination device performs the lane-in determination and the lane-out determination on the basis of a change amount and a change direction at a relative position with respect to the detected boundary line in the vehicle width direction of the front vehicle. [3] Vehicle speed control device according to claim 1 or 2, wherein the vehicle detection device performs the lane-in detection and lane-out detection by the first detection device when the distance detection device determines that the front vehicle is within the detection distance range, and the lane-in detection and lane-out detection by the second detection device when the distance detection device determines that the front vehicle is outside the detection distance range. [4] Vehicle speed control device according to one of claims 1 to 3, wherein the vehicle detection device calculates an approach or crossing degree of the front vehicle with respect to the detected boundary line as a parameter indicating the relative position with respect to the detected boundary line in the vehicle width direction of the front vehicle, and performs the lane-cut determination and lane-out determination on the basis of the calculated degree. [5] Vehicle speed control device according to any one of claims 1 to 4, further comprising: - a state determination device that determines whether or not a driving state of the own vehicle is a stable driving state with respect to the detected boundary line, wherein the vehicle determination device performs the lane-in determination and the lane-out determination on the basis of the relative position with respect to the detected boundary line in the vehicle width direction of the front vehicle, if the state determination device determines that the driving state of the own vehicle is a stable driving state with respect to the detected boundary line. [6] Speed ​​control method by a vehicle speed control device (10) in which an imaging device (21) for imaging an area in front of a self-propelled vehicle (50) is attached, the method comprising the following steps: - a boundary line detection step for detecting a lane boundary line (61) defining a self-driving lane (63) that is a lane driven on by the self-driving vehicle, based on an image captured by the imaging device; - a vehicle determination step for performing a merging determination and a merging determination with respect to a front vehicle (51) traveling in front of the own vehicle, wherein the front vehicle traveling in an adjacent lane (64) adjacent to the own lane is determined as a vehicle merging into the own lane based on a relative position (VL) with respect to a detected boundary line, which is the lane boundary line detected by the boundary line detection step, in the vehicle width direction of the front vehicle, and the front vehicle traveling in the own lane is determined as a merging vehicle merging out of the own lane; and - a distance determination step to determine whether or not the front vehicle is within a detection distance range of the detected boundary line, which is detected by the boundary line detection step, wherein - the vehicle identification step includes: - Performing the lane-in determination and the lane-out determination based on the relative position with respect to the detected boundary line in the vehicle width direction of the front vehicle, if the distance determination step determines that the front vehicle is within the detection distance range, and - a first determination step to perform the lane-in determination and the lane-out determination based on the relative position with respect to the detected boundary line in the vehicle width direction of the front vehicle, and a second determination step to perform the lane-in determination and the lane-out determination based on a relative position with respect to the own vehicle in the vehicle width direction of the front vehicle, and wherein the vehicle determination step prevents the execution of the lane-in determination and the lane-out determination by the second determination step if the distance determination step determines that the front vehicle is within the detection distance area. [7] Vehicle speed control device (10) in which an imaging device (21) for imaging an area in front of a self-propelled vehicle (50) is attached, wherein the vehicle speed control device comprises: - a boundary line detection device that detects a lane boundary line (61) that defines a self-driving lane (63) that is a lane driven on by the self-driving vehicle, based on an image captured by the imaging device; - a vehicle identification device that performs a lane-entry determination and a lane-out determination with respect to a front vehicle (51) traveling in front of the vehicle itself, wherein the front vehicle traveling on an adjacent lane (64) adjacent to the vehicle itself is determined as a lane-entry vehicle merging into the vehicle itself, and the front vehicle traveling on the vehicle itself is determined as a lane-out vehicle merging out of the vehicle itself, based on a relative position (VL) with respect to a detected boundary line, which is the lane boundary line detected by the boundary line detection device, in a vehicle width direction of the front vehicle; and - a state determination device that determines whether or not a driving state of the own vehicle is a stable driving state with respect to the detected boundary line, wherein - the vehicle determination device performs the lane-in determination and the lane-out determination based on the relative position with respect to the detected boundary line in the vehicle width direction of the vehicle in front, if the state determination device determines that the driving state of the own vehicle is a stable driving state with respect to the detected boundary line. [8] Speed ​​control method by a vehicle speed control device (10) in which an imaging device (21) for imaging an area in front of a self-propelled vehicle (50) is mounted, the method comprising the following steps: - a boundary line detection step for detecting a lane boundary line (61) defining a self-driving lane (63) that is a lane driven on by the self-driving vehicle, based on an image captured by the imaging device; - a vehicle determination step for performing a merging determination and a merging determination with respect to a front vehicle (51) traveling in front of the own vehicle, wherein the front vehicle traveling in an adjacent lane (64) adjacent to the own lane is determined as a vehicle merging into the own lane based on a relative position (VL) with respect to a detected boundary line, which is the lane boundary line detected by the boundary line detection step, in the vehicle width direction of the front vehicle, and the front vehicle traveling in the own lane is determined as a merging vehicle merging out of the own lane; and - a state determination step to determine whether or not a driving state of the own vehicle is a stable driving state with respect to the detected boundary line, wherein - The vehicle determination step includes: performing the lane-in determination and the lane-out determination based on the relative position with respect to the detected boundary line in the vehicle width direction of the vehicle in front, if the state determination step determines that the driving state of the own vehicle is a stable driving state with respect to the detected boundary line.

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