Vehicle control device

Abstract

A vehicle control device (9) assists in the confirmation of the rear side of the host vehicle (3A). The vehicle control device (9) includes a position estimation section (21), an SN index calculation section (23), a lane determination section (25), and an alarm determination section (27). The position estimation section (21) estimates the lateral position of another vehicle (3B) based on a reflected wave of a radar wave. The SN index calculation section (23) calculates an SN index representing the relationship between the level of a signal and the level of noise based on a reflected wave of a radar wave. The lane determination section (25) makes a determination of the lane based on the SN index in the case where the lane in which another vehicle (3B) is traveling is determined based on information on the lateral position of another vehicle (3B). The alarm determination section (27) determines whether or not another vehicle (3B) satisfies a condition in which an alarm should be issued based on the determination result of the lane.

Description

[0001] Cross-reference to related applications

[0002] This international application claims priority based on Japanese Patent Application No. 2020-203415, filed with the Japan Patent Office on December 8, 2020, and incorporates the entire contents of Japanese Patent Application No. 2020-203415 by reference. Technical Field

[0003] This disclosure relates to technology for a blind spot monitor capable of identifying the rear side of the vehicle and issuing an alert as needed. Background Technology

[0004] Previously, there were technologies known to monitor the surroundings of a vehicle using radar and to control the vehicle based on the status of other vehicles obtained from the radar (for example, see Patent Document 1).

[0005] In addition, in recent years, a technology known as blind spot monitor (BSM) has been developed.

[0006] The technology of BSM (hereinafter referred to as BSM control) refers to the technology that assists in the confirmation of the rear side (i.e., diagonally rear) of the vehicle in order to suppress contact with other vehicles when changing lanes or during the driving of the vehicle.

[0007] In other words, BSM control refers to the use of radar to detect other vehicles traveling in the same direction in adjacent lanes and to report the presence of other vehicles in areas that are not easily visible to the driver (e.g., blind spots to the rear). In this BSM control, when the vehicle changes lanes, or when other vehicles are present in areas that are not easily visible to the driver, an alert is issued to the driver via display or sound.

[0008] Patent Document 1: Japanese Patent Application Publication No. 2019-2863

[0009] The inventors' detailed research into the aforementioned technology revealed the following issues.

[0010] In the case of multiple lanes with the same direction of travel, when radar detects other vehicles traveling in lanes different from the lane in which the vehicle is traveling (i.e., the current lane), there is a possibility that the following problems may occur.

[0011] Here, for example, as will be described later. Figure 5 As shown, an example is given of a situation where, while the vehicle is traveling in the first lane, another vehicle (i.e., the target vehicle) is traveling diagonally behind the vehicle in the third lane.

[0012] In a case where it is determined by the radar that the other vehicle is traveling on the third lane, even if the host vehicle makes a lane change to the second lane, the possibility of collision between the host vehicle and the other vehicle is low, so an alarm is not generally issued.

[0013] However, in a case where the host vehicle changes to a situation in which the host vehicle and the other vehicle are traveling on adjacent lanes, for example, in a case where the other vehicle has made a lane change to the second lane, if the host vehicle makes a lane change to the second lane, there is a possibility of collision. Therefore, for example, in a case where the other vehicle has made a lane change to the second lane, if the host vehicle makes a lane change, there is a possibility of collision, an alarm can be issued before the host vehicle makes a lane change.

[0014] However, in a case where the position of the other vehicle is detected by reflection of the electric wave from the radar, there is a possibility that the position of the other vehicle cannot be correctly detected due to some reason. In other words, there is a concern that the lateral position of the other vehicle indicating on which lane the other vehicle is traveling cannot be detected with good accuracy.

[0015] Therefore, in a case where the other vehicle is actually traveling on the third lane, but is erroneously determined to be traveling on the second lane, there is a concern that an alarm is issued although it is not necessary. SUMMARY

[0016] In one aspect of the present disclosure, it is desirable to provide a technique capable of accurately estimating a lane on which another vehicle is traveling and capable of appropriately issuing an alarm in BSM control.

[0017] One aspect of the present disclosure relates to a vehicle control device (9) that uses a radar wave to assist in the above-described confirmation of the rear side of the host vehicle.

[0018] The vehicle control device includes a position estimation section (21, S110), an SN index calculation section (23, S210), a lane determination section (25, 340), and an alarm determination section (27, 360).

[0019] The position estimation section is configured to estimate a lateral position indicating a position of the other vehicle (3B) in a width direction of a road, based on a reflected wave of the radar wave irradiated from the host vehicle to the surroundings.

[0020] The SN index calculation section is configured to calculate an SN index indicating a relationship of a level of a signal in the reflected wave relative to a level of noise, based on the reflected wave of the radar wave irradiated from the host vehicle to the surroundings.

[0021] The lane determination unit is configured to determine the lane in which the other vehicle is traveling based on the SN index calculated by the SN index calculation unit, in a case where it is determined that the other vehicle is traveling in the lane based on the information on the lateral position of the other vehicle estimated by the position estimation unit.

[0022] The alarm determination unit is configured to determine whether or not the other vehicle satisfies a condition for which an alarm should be issued, based on the determination result determined by the lane determination unit.

[0023] With such a configuration, in one aspect of the present disclosure, the lane in which the other vehicle is traveling (i.e., the traveling lane) can be determined with good accuracy, so an alarm can be appropriately issued with respect to the other vehicle traveling in a dead angle region or the like on the rear side of the host vehicle (i.e., from the driver's observation diagonal rear side) at the time of a lane change of the host vehicle or the like.

[0024] Hereinafter, a detailed description will be given.

[0025] Among the reflected waves of the radar waves, the SN index indicating the relationship of the level of the signal (i.e., S) based on the target (i.e., the other vehicle) with respect to the level of the noise (i.e., noise: N) has an influence on the estimation accuracy of the lateral position of the other vehicle.

[0026] The SN index is, for example, a ratio of the level of the signal with respect to the level of the noise (i.e., SN ratio: S / N), a difference between the level of the signal and the level of the noise (i.e., SN difference: S-N), or the like, and is a different index indicating the magnitude of the level of the signal and the level of the noise, and the estimation accuracy of the lateral position of the other vehicle differs depending on the magnitude of the SN index. Further, in a case where the level is expressed in terms of height or the like, the magnitude of the level can be expressed in terms of height.

[0027] For example, in a case where the SN ratio or the SN difference is large, the estimation accuracy of the lateral position is high, and on the other hand, in a case where the SN ratio or the SN difference is small, the estimation accuracy of the lateral position is low. Therefore, in determining the traveling lane of the other vehicle, the determination is made taking into account the SN ratio or the SN difference, whereby the determination of the traveling lane of the other vehicle can be made more reliably.

[0028] Therefore, for example, in a case where the determination accuracy of the traveling lane of the other vehicle is high, an alarm can be appropriately issued based on the determination result thereof. On the other hand, in a case where the determination accuracy of the traveling lane of the other vehicle is low, the determination accuracy of the traveling lane can be improved, for example, by further taking into account other conditions or the like, and an alarm can be appropriately issued based on the determination result thereof.

[0029] In other words, in one aspect of the present disclosure, it is possible to appropriately issue an alarm when an alarm should be issued at the time of a lane change of the host vehicle or the like, and it is possible to suppress an alarm from being issued at random when an alarm does not need to be issued, thus achieving a remarkable effect. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a block diagram showing the configuration of the vehicle control system of the first embodiment.

[0031] Figure 2 is an explanatory diagram showing the inspection range of the radar device of the vehicle.

[0032] Figure 3 is a block diagram functionally showing the vehicle control device.

[0033] Figure 4 is a flowchart showing the main processing performed by the vehicle control device.

[0034] Figure 5 is an explanatory diagram showing a vehicle traveling on a road having a plurality of lanes.

[0035] Figure 6 is an explanatory diagram showing the observation point, the travel position of the other vehicle, and the like detected by the radar device in the case where the other vehicle is traveling on the third lane.

[0036] Figure 7 is a flowchart showing the alarm processing performed by the vehicle control device.

[0037] Figure 8 is a flowchart showing the content of the alarm processing performed by the vehicle control device in detail.

[0038] Figure 9 is an explanatory diagram showing the SN difference calculated from the data detected by the radar device in the case where the other vehicle is traveling on the third lane.

[0039] Figure 10 is an explanatory diagram showing the processing at the time when there is a wall in the vicinity of the other vehicle traveling on the outer side in the second lane.

[0040] Figure 11 is an explanatory diagram showing the processing at the time when there is a wall in the vicinity of the other vehicle traveling on the inner side in the third lane.

[0041] Figure 12 is a flowchart showing the processing for setting the counter threshold value in the second embodiment. DETAILED DESCRIPTION

[0042] Embodiments of the present disclosure will be described below with reference to the accompanying drawings.

[0043] [1. First Embodiment]

[0044] [1-1. Overall Configuration]

[0045] First, the overall configuration of a vehicle control system including a vehicle control device in the present first embodiment will be described.

[0046] As shown in Figure 1 , the vehicle control system 1 of the present first embodiment is mounted on a vehicle 3 (for example, refer to Figure 2 ), and is configured as a system that checks objects around the vehicle 3 and issues an alarm as needed. The vehicle control system 1 is provided with two radar devices 5L, 5R, an alarm device 7, and a vehicle control device 9. Further, hereinafter, the vehicle 3 will be sometimes described by being divided into a host vehicle 3A and another vehicle 3B.

[0047] As shown in Figure 2 , the radar device 5L is a left-side radar device provided on the left side of the rear portion of the vehicle 3, and the radar device 5R is a right-side radar device provided on the right side of the rear portion of the vehicle 3. The configurations and functions of the two radar devices 5L, 5R are basically the same. Hereinafter, the two radar devices 5L, 5R will also be collectively referred to as the radar device 5. Further, the vehicle control system 1 can be provided with three or more radar devices as long as it is provided with at least one radar device.

[0048] The radar device 5 is a detection device that uses a publicly known electric wave to repeatedly transmit and receive a radar wave to monitor the periphery of the vehicle 3. As the radar device 5, for example, a millimeter wave radar using a millimeter wave can be employed. Further, for example, an electric wave having a frequency of 30 GHz or more and a wavelength of 1 cm or less can be employed as the radar wave.

[0049] In the present first embodiment, a transmission signal modulated by an FMCW method and a transmission signal modulated by a 2FCW method are used to detect an object (i.e., a target) as a target, but are not limited thereto. Further, FMCW is an abbreviation of Frequency Modulated Continuous Wave. 2FCW is an abbreviation of 2Frequency Continuous Wave.

[0050] Further, in the FMCW method and the 2FCW method, as is publicly known, there are advantages and disadvantages respectively, so data of a method having higher checking accuracy can be employed as is publicly known (for example, refer to Japanese Patent Application Publication No. 2019-2863) according to the situation around and the like.

[0051] The radar devices 5L, 5R respectively check objects including moving objects existing in an object checking region by transmitting radar waves toward the left and right sides, etc. of the rear of the vehicle 3A from each position. For example, the radar devices 5L, 5R check other vehicles 3B, etc. such as a car and a two-wheeled vehicle in the rear, the oblique rear, and the side of the vehicle 3A.

[0052] Further, in Figure 2 , the object checking region Rrr of the right radar device 5R is shown in a hatched region in a horizontal plane. The object checking region Rrl of the left radar device 5L is symmetric with the object checking region Rrr, and the outer periphery of the region is shown in a dotted line.

[0053] The radar device 5 has a function as a transmitter that transmits a transmission wave based on a prescribed transmission signal, and a function as a radar sensor that receives a reflection wave returned from an object that has reflected the transmission wave as a reception wave. Further, the radar device 5 converts the reception wave as an analog waveform into a digital signal, and transmits the reception wave converted into a digital signal, i.e., an AD waveform, to the vehicle control device 9.

[0054] The alarm device 7 is a known device that gives an alarm upon receiving an instruction from the vehicle control device 9 when the vehicle control device 9 checks a moving object approaching from the rear or the oblique rear, etc. of the vehicle 3. The alarm device 7 has, for example, a sound output device provided in the vehicle cabin that outputs an alarm sound to the passenger of the vehicle 3. Alternatively, a display lamp, etc. provided in the instrument panel, etc. in front of the rearview mirror or the driver's seat displays light that gives an alarm.

[0055] [1-2. Electrical structure of vehicle control device]

[0056] Next, the electrical structure of the vehicle control device 9 will be described.

[0057] As shown in Figure 1 , the vehicle control device 9 is an electronic control device constituted around a known microcomputer (i.e., a microprocessor) 15 having a CPU 11 and a memory 13 such as a ROM and a RAM.

[0058] The various functions of the microcomputer 15 are realized by the CPU 11 executing a program stored in a non-transitory tangible recording medium. In this example, the memory 13 corresponds to the non-transitory tangible recording medium in which the program is stored. In addition, by the execution of the program, a method corresponding to the program is executed.

[0059] Further, the non-transitory tangible recording medium refers to a recording medium other than an electromagnetic wave. In addition, a part or all of the functions executed by the CPU 11 can be constituted in hardware by one or a plurality of ICs, etc. In addition, the number of microcomputers 15 constituting the vehicle control device 9 can be one or a plurality.

[0060] As will be described later, the above vehicle control device 9 estimates the lateral position (i.e., the position in the width direction of the lane) of the other vehicle 3B based on the signal of the reflected wave of the radar wave obtained from the radar device 5, and determines in which lane the other vehicle 3B is traveling. Also, an alarm is issued as needed (for example, in the case where there is a possibility of collision).

[0061] In other words, the vehicle control device 9 assists in the confirmation of the rear side of the host vehicle 3A in order to achieve safety when the host vehicle 3A changes lanes on a road having a plurality of lanes.

[0062] In detail, the vehicle control device 9 detects the lane in which the other vehicle 3B is traveling in accordance with the position of the other vehicle 3B (for example, the other vehicle 3B on the rear side of the host vehicle 3A) traveling in the same direction as the host vehicle 3A. Also, in the case where the host vehicle 3A has changed lanes to the side of the lane in which the other vehicle 3B is traveling, an alarm is issued when it is determined that there is a possibility of contact between the host vehicle 3A and the other vehicle 3B.

[0063] Here, the rear side of the host vehicle 3A means the obliquely rearward side when viewed from the driver sitting in the driver's seat, and refers to a region in which the driver does not easily visually confirm the other vehicle 3B, such as a dead angle of a rearview mirror 17 (for example, refer to Figure 2 ), and the like. For example, as the rear side of the host vehicle 3A, a range behind the front side of the driver (i.e., the driver's seat) in a lane other than the host lane can be cited.

[0064] The vehicle control device 9 has a position estimation section 21, an SN index calculation section 23, a lane determination section 25, and an alarm determination section 27, as shown by the functions of Figure 3 .

[0065] The position estimation section 21 is configured to estimate a lateral position (i.e., a lateral position with respect to the host vehicle 3A) indicating the position of the other vehicle 3B in the width direction of the road based on the reflected wave of the radar wave irradiated from the host vehicle 3A to the surroundings.

[0066] The SN index calculation section 23 is configured to calculate an SN index indicating the relationship of the level of the signal in the reflected wave of the radar wave irradiated from the host vehicle 3A to the surroundings with respect to the level of the noise based on the reflected wave of the radar wave.

[0067] Here, as is known, the noise level is, for example, the strength of the entire signal in the reflected wave, or the strength of the signal after removing signals of a predetermined level or higher (e.g., signals that can be estimated to represent the target) from the entire reflected wave. Furthermore, the signal level refers to the strength of the signal representing the target in the reflected wave (i.e., the signal reflected at the target). This strength can be expressed, for example, by the power or voltage of the reflected wave.

[0068] Therefore, the SN index, which represents the relationship between the signal level and the noise level, indicates the degree to which the target signal level differs from the noise level; that is, it is an index representing the difference in magnitude between the two levels. This can be expressed as a ratio (e.g., S / N:SN ratio) or a difference (e.g., S-N:SN difference) between the two levels. Furthermore, when the two levels are represented, for example, by voltage, the difference in magnitude between the two levels can be expressed as the relationship between the voltage levels.

[0069] Furthermore, in this first embodiment, the SN index calculation unit 23 is configured to calculate the SN ratio, which represents the ratio of the noise level to the signal level in the reflected radar wave irradiated from the vehicle 3A to the surrounding area.

[0070] The lane determination unit 25 is configured to determine the lane in which the other vehicle 3B is traveling based on the information of the lateral position of the other vehicle 3B estimated by the position estimation unit 21, and to determine the lane in which the other vehicle 3B is traveling based on the SN index (e.g., SN ratio) calculated by the SN index calculation unit 23.

[0071] The alarm determination unit 27 is configured to determine, based on the determination result determined by the lane determination unit 25, whether the conditions for issuing an alarm are met for other vehicles 3B. Therefore, if the conditions for issuing an alarm are met, an alarm can be issued.

[0072] [1-3. Processing Content]

[0073] Next, the various processes performed by the vehicle control unit 9 will be explained based on flowcharts and the like. These processes are performed repeatedly according to each prescribed cycle (e.g., each scan of the radar unit 5).

[0074] [1-3-1. Main Processing]

[0075] First, based on Figure 4 The flowchart illustrates the overall (i.e., main process) of the processing performed by the vehicle control unit 9.

[0076] like Figure 4 As shown, in step (hereinafter referred to as S) 100, observation point calculation processing is performed to obtain the observation point by a known method.

[0077] In the observation point calculation processing, first, a waveform (i.e., an AD waveform) of a reflected wave (i.e., a reception wave) of a radar wave irradiated from the radar device 5 is acquired.

[0078] Next, an FFT waveform is generated. The FFT waveform is a waveform obtained by performing a well-known fast Fourier transform on the AD waveform. Further, FFT is an abbreviation of Fast Fourier Transform.

[0079] Next, based on the FFT waveform, a reflection point of the radar wave, i.e., an observation point, is calculated.

[0080] In detail, the observation point calculation processing is implemented, for example, as follows.

[0081] First, the vehicle control device 9 generates a frequency difference signal, i.e., a beat signal, which takes a frequency difference between a transmission signal and a reception signal as a frequency, from the AD waveform.

[0082] Then, a frequency analysis processing based on FFT is performed on the generated beat signal, and a frequency spectrum as the FFT waveform is generated. At this time, the frequency spectrum is generated from the beat signal in accordance with each modulation method.

[0083] Further, the frequency spectrum is data indicating a relationship between each frequency component of the transmission signal from the radar device 5 and a signal intensity corresponding to each frequency component. Further, the signal intensity can be indicated by a power, a voltage of the received signal.

[0084] In the present first embodiment, an object, i.e., a target, is examined by a well-known FMCW method. Here, a frequency spectrum of a frequency rising portion and a frequency falling portion of the beat signal is found, and based on the frequency spectrum, an azimuth θ and power information of the object are extracted. Then, using the extracted azimuth θ and power information, a speed (i.e., a relative speed) of the object (e.g., the other vehicle 3B) with respect to the host vehicle 3A and a distance R from the host vehicle 3A to the other vehicle 3B are calculated.

[0085] In addition, in the present first embodiment, an object is also examined by a well-known 2FCW method. In other words, a frequency spectrum is generated from each of two beat signals of two transmission frequencies, and based on the generated two frequency spectra, an azimuth θ and power information of the other vehicle 3B are extracted. Then, using the extracted azimuth θ and power information, a speed (i.e., a relative speed) of the other vehicle 3B with respect to the host vehicle 3A and a distance R from the host vehicle 3A to the other vehicle 3B are calculated.

[0086] Here, it is possible to select which of the distance R and azimuth θ obtained by the FMCW method and the 2FCW method to use, using the methods known as described in the aforementioned publications. Furthermore, the location of the radar wave reflection point, i.e., the observation point, can be determined based on the distance R and azimuth θ.

[0087] Next, in S110, a known smoothing position recognition process is performed. This smoothing position recognition process refers to the process of estimating the driving position (i.e., driving position) of other vehicles 3B by smoothing (i.e., filtering) the data of the observation points obtained in S100 above.

[0088] In other words, smooth position recognition processing refers to the process of obtaining the driving position of other vehicles 3B, i.e., the smooth position, through filtering based on the data of the observation point. It can estimate the trajectory of other vehicles 3B based on the time change of the smooth position.

[0089] <Here, the relationship between the observation point and the smoothing position is explained.>

[0090] For example, such as Figure 5 As shown, in the case of multiple lanes with the same direction of travel (i.e., lanes on one side), if the lane in which vehicle 3A travels (i.e., this lane) is designated as the first lane, then the lane adjacent to this lane is designated as the second lane, and the lane adjacent to the second lane and on the opposite side of this lane is designated as the third lane.

[0091] In addition, the boundary line between the first lane and the second lane (i.e., the lane boundary line) is designated as the first lane boundary line, and the boundary line between the second lane and the third lane is designated as the second lane boundary line.

[0092] Furthermore, for example, if another vehicle 3B is traveling in the third lane diagonally behind this vehicle 3A, the radar device 5 can estimate the driving position of the other vehicle 3B and thus estimate its trajectory.

[0093] exist Figure 6 This example illustrates the observation point and driving position (i.e., smooth position) data of vehicle 3B when vehicle 3A and other vehicle 3B are traveling in the same direction in different lanes. Furthermore, in this example, other vehicle 3B is actually traveling in the third lane. Figure 6 The dashed line indicates the target driving position, which represents the actual trajectory of other vehicles 3B.

[0094] In addition, Figure 6In this first embodiment, the driving position of other vehicles 3B obtained through radar device 5 is used as the radar identification result, but this driving position is the driving position before considering the SN ratio. In other words, in this first embodiment, as described later, the SN ratio is considered to improve the estimation accuracy of the driving position of other vehicles 3B.

[0095] In addition, in Figure 6 The estimated position of other vehicle 3B is either in the third lane or the second lane. That is, the estimated position of other vehicle 3B is... Figure 6 In the case of driving on the third lane side below the second lane boundary line (i.e., the third lane side), it is set as driving on the third lane. Figure 6 When the vehicle is positioned above the boundary line of the second lane (i.e., on the side of the second driving lane), it is set to drive in the second driving lane.

[0096] In addition, Figure 6 In this context, lateral position refers to the distance from vehicle 3A in the width direction when the position of vehicle 3A (i.e., the center position of vehicle 3A in the width direction) is set to 0m. The lateral position increases towards the third lane. Longitudinal position refers to the distance behind vehicle 3A when the position of vehicle 3A (i.e., the center position of vehicle 3A in the direction of travel) is set to 0m. The absolute value of the longitudinal position increases towards the rear. Furthermore, the rear position is displayed as a negative number.

[0097] As is well known, the driving position (i.e., smoothed position) of the other vehicle 3B can be determined by using data from the observation point through various filtering processes.

[0098] In this first embodiment, a general Kalman filter is used for filtering.

[0099] This filtering process, which uses a Kalman filter, estimates the most appropriate (i.e., the one with the smallest covariance of the estimation error) state of the system based on information up to immediately before (i.e., predictions) and the data acquired this time (i.e., observations). However, it assumes that the measured values ​​(i.e., data) have noise based on a normal distribution, and that the variables representing the system's state themselves also have noise based on a normal distribution.

[0100] Specifically, the following two steps are repeated over time. In other words, the transition from the "Correct" step to the "Predict" step and from the "Predict" step back to the "Correct" step is repeated.

[0101] The "Correct" step [a: update of observations, b: estimate of the current value]

[0102] "Prediction" step [c: update of time, d: prediction of next value]

[0103] Further, "prediction" indicates a state in which prediction is performed using the last value, and is also referred to as prior estimation. In addition, "estimation" indicates a state in which estimation is performed using the prediction, and is also referred to as posterior estimation. In addition, "prediction" and "estimation" are respectively performed based on a prescribed model.

[0104] Further, in addition to the above-described filtering processing, a publicly known filtering processing such as the α-β filtering processing described in Japanese Patent Application Publication No. 2020-12795, for example, can be adopted.

[0105] Returning to the above Figure 4 , next in S120, an alarm processing is performed as described later. The alarm processing refers to a processing of further considering a condition of an SN ratio described later with respect to the information of the travel position of the other vehicle 3B, which is calculated in S110, to calculate a travel lane of the other vehicle 3B, and for example, in a case where the host vehicle 3A has performed a lane change to the second lane, to determine whether there is a concern that the host vehicle 3A contacts the other vehicle 3B.

[0106] Next in S130, an output processing is performed, and the present processing is temporarily ended. The output processing refers to a processing of, in a case where the host vehicle 3A has performed a lane change to the second lane, when there is a concern that the host vehicle 3A contacts the other vehicle 3B, issuing an alarm to the driver using the alarm device 7.

[0107] [1-3-2. Alarm processing]

[0108] Next, a summary of the above-described alarm processing of S120 is described based on the flowchart shown in FIG. 6. Figure 7

[0109] The alarm processing is a processing of performing a prescribed alarm determination in a case where the other vehicle 3B that is determined to be traveling on the third lane has performed a lane change to the second lane.

[0110] In detail, as described later, in a case where the SN ratio of the reflected wave of the radar wave is higher than a prescribed value, it is determined that there is a high possibility of traveling on the second lane, and an alarm determination is performed further considering other conditions such as the inter-vehicle distance, the vehicle speed, and the like. On the other hand, in a case where the SN ratio is below the prescribed value, there is a possibility of traveling on the third lane, and the degree of the possibility is spent to determine the degree of the possibility, and an alarm determination is performed considering the above-described other conditions.

[0111] Further, as is publicly known, the SN ratio of the reflected wave of the radar wave refers to a power ratio of the FFT spectrum (i.e., signal) with respect to the background noise, and for example, can be calculated by the radar device 5 or the vehicle control device 9. ​

[0112] like Figure 7 As shown, firstly, in S200, third lane driving monitoring processing is performed. This third lane driving monitoring processing is the process of monitoring whether other vehicles 3B are driving in the third lane.

[0113] In other words, in order to detect cases where other vehicle 3B changes lanes from the third lane to the second lane (i.e., merges), such as when other vehicle 3B changes lanes from the third lane to the second lane, the process of identifying and monitoring other vehicle 3B traveling in the third lane is first performed.

[0114] Next, in S210, the second lane driving counter operation process is performed. This second lane driving counter operation process refers to the process of setting the value of a predetermined counter used to determine whether another vehicle 3B is driving in the second lane. In other words, as detailed later, it is a process of setting the value of the second lane driving counter based on factors such as the SN ratio of the reflected radar wave. Furthermore, the SN ratio is obtained in advance from the radar device 5 or calculated by the vehicle control device 9 before performing the second lane driving counter operation process.

[0115] Next, in S220, an alarm determination process is performed, and this process is temporarily terminated. This alarm determination process refers to the process used to determine whether to issue the aforementioned alarm.

[0116] [1-3-3. Details of Alarm Handling]

[0117] Next, based on Figure 8 The flowchart above Figure 7 The specific details of alarm handling described in the document will be explained in detail.

[0118] also, Figure 8 The processing of S300 to S320 is equivalent to Figure 7 The third lane driving monitoring and processing of the S200 Figure 8 The processing of the S330 is equivalent to Figure 7 The operation processing of the second lane travel counter on S210 Figure 8 The processing of S340 to S370 is equivalent to Figure 7 The alarm judgment and processing of S220.

[0119] Third Lane Driving Monitoring and Processing

[0120] like Figure 8In the flowchart shown in FIG. 9, in S300, it is determined whether or not the precondition for the third lane travel is satisfied with respect to the object of determination, that is, the target (that is, the other vehicle 3B). If the affirmative determination is made, the process proceeds to S310, whereas if the negative determination is made, the process proceeds to S320.

[0121] Next, the above precondition will be described.

[0122] The precondition refers to a condition for determining whether or not the other vehicle 3B is traveling on the third lane, and as described in Table 1 below, in a case where the conditions [Condition ZJ1] and [Condition ZJ2] are satisfied (that is, the conditions are met), it is determined that the other vehicle 3B is traveling on the third lane.

[0123] [Table 1]

[0124] [Precondition: Condition]

[0125] ZJ1 Driving on the third lane ZJ2 Third lane is present

[0126] In detail, [Condition ZJ1] is a condition that "the other vehicle 3B is traveling on the third lane", and can be determined based on the smoothed position (that is, the travel position) of the other vehicle 3B obtained by the above-described smoothed position recognition processing. In other words, the lane on which the other vehicle 3B is traveling can be determined based on the lateral position of the other vehicle 3B. For example, in a case where the lateral position of the other vehicle 3B is within a prescribed range corresponding to the prescribed lane, it can be determined that the other vehicle 3B is traveling on the prescribed lane. In addition, the warning timing is not changed for the other vehicle 3B traveling outside the third lane.

[0127] [Condition ZJ2] is a condition that "there is a third lane", and can be determined based on the state of the reflected wave of the radar wave, and the like. In other words, in a case where there is a distance on the second lane side (that is, the outer side) of the host vehicle 3A sufficient for the third lane to exist, it can be determined that there is a third lane.

[0128] In detail, for example, in a case where there is a wall extending along the road, since the distance from the host vehicle 3A to the wall can be detected by the radar device 5, it can be determined whether or not there is a third lane based on the distance.

[0129] In addition, this determination is made because in a case where there is a wall on the outer side of the second lane, even when the other vehicle 3B is traveling on the second lane, there is a possibility that the other vehicle 3B is pulled by the wall (that is, is affected by the wall), and there is a possibility of false determination that the other vehicle 3B is traveling on the third lane.

[0130] In addition, other conditions can be further considered in addition to [Condition ZJ1] and [Condition ZJ2]. For example, at least one of [Condition ZJ3], "the distance in the travel direction from the host vehicle 3A to the other vehicle 3B (i.e., the longitudinal distance) is equal to or greater than a prescribed value," and [Condition ZJ4], "the number of times of tracking (i.e., the number of times of being continuously connected) is equal to or greater than a prescribed number of times," can be added as the condition.

[0131] Further, in S310, which is entered when the above-described precondition is satisfied, the monitoring flag is set (i.e., turned on) for the corresponding other vehicle 3B. In other words, the corresponding other vehicle 3B is set as a monitoring target. Hereinafter, ON is described as being turned on.

[0132] Then, in the following processing, it is determined whether the other vehicle 3B, which is the monitoring target with the monitoring flag being ON, i.e., the other vehicle 3B traveling on the third lane, performs a lane change (i.e., merges) to the second lane.

[0133] Next, in S320, it is determined whether a third-lane-travel monitoring condition is satisfied. In other words, it is determined whether the monitoring flag is ON for the other vehicle 3B, which is the monitoring target this time. If the affirmative determination is made, S330 is entered, whereas if the negative determination is made, S360 is entered.

[0134] <Second-lane-travel counter operation processing>

[0135] In S330, second-lane-travel counter operation processing is performed. The second-lane-travel counter operation processing refers to processing of operating a second-lane-travel counter (hereinafter, referred to as a travel counter). In other words, the second-lane-travel counter operation processing refers to processing of operating the travel counter used to determine whether the other vehicle 3B, which is the monitoring target, has performed a lane change from the third lane to the second lane.

[0136] The travel counter is a counter used when it is determined whether the other vehicle 3B is traveling on the second lane. As shown in Table 2 below, the counter value is incremented or decremented, or the like, when a prescribed condition is satisfied.

[0137] By the travel counter, it is possible to determine, using the SN ratio, the adjacent-lane probability, or the like, as described later, whether the lateral position shift during the third-lane travel caused by the decrease in the SN ratio (i.e., the mis-detection of the lane) or the actual travel on the second lane. Further, the greater the counter value, the higher the possibility of traveling on the second lane.

[0138] Hereinafter, a detailed description will be given based on Table 2 below.

[0139] Further, the initial value of the travel counter is 0, the maximum value is 5, and the minimum value is 0. In addition, there is a relationship of S1 > S2 > S3 among S1, S2, S3 of the SN threshold, and for example, values of 44 dB, 40 dB, 35 dB can be adopted as S1, S2, S3, respectively. Further, the SN threshold refers to a threshold value set for determining the level of the SN ratio, and can be set through experiments and the like.

[0140] [Table 2]

[0141]

[0142] <Operation (A) case>

[0143] In a case where the SN ratio is equal to or higher than the SN threshold (for example, S1) as a prescribed threshold value, and the target of the monitoring object (that is, the other vehicle 3B) is a target that has been continuously recognized as the same target from the last time (that is, in a case where the connection state is continuous), the travel counter is incremented by 1 (for example, incremented by 1). Here, the adjacent lane probability is not used.

[0144] Further, as is known, the connection state being continuous indicates a state in which the same target has been continuously checked from the last time to this time, and in a case where a prescribed condition (a condition in which the same target can be determined) is satisfied, it is determined that it is continuous.

[0145] The operation (A) case indicates a state in which the SN ratio is high, and the accuracy of the position of the reflection point, that is, the angle, is stable. Further, in a case where the position of the reflection point is within the range of the target, the angle is stable.

[0146] Therefore, in a case where it is estimated based on the signal from the radar device 5 that the travel position (that is, the smoothed position) of the other vehicle 3B is the second lane, in a state in which the SN ratio is high and the angle is stable, it is actually highly likely that the other vehicle 3B merges from the third lane to the second lane.

[0147] <Operation (B) case>

[0148] In a case where the SN ratio is within a prescribed range of the SN threshold (for example, equal to or higher than S2 and less than S1), and the adjacent lane probability P(t) is equal to or higher than 70%, and the connection state is continuous, the travel counter is incremented by 1 (for example, incremented by 1).

[0149] Here, the adjacent lane probability is known as described in, for example, Japanese Patent Application Publication No. 2016-85567, and the like, so a simple explanation will be given. In other words, the adjacent lane probability refers to a probability that a target exists in a lane adjacent to the own lane (that is, the second lane), and can be expressed by, for example, the following formula (1).

[0150] P(t) = P0 2 + P(t-1) 0 7 · · · (1)

[0151] P: adjacent lane probability (instantaneous value)

[0152] P(t): adjacent lane probability (filtered value)

[0153] t: period of processing for solving the adjacent lane probability

[0154] In the case of this operation (B), it is difficult to determine only by the SN ratio whether the other vehicle 3B is traveling in the third lane or merging into the second lane, so the determination is made further considering the condition of the adjacent lane probability.

[0155] <Operation (C) case>

[0156] In the case where the SN ratio is below a prescribed SN threshold (for example, S3) and the connection state is continuous, the travel counter is decremented by 1 (for example, by 1). Here, the adjacent lane probability is not used.

[0157] In the case of this operation (C), since the SN is low, the angle is unstable, that is, since the accuracy is low even when the travel position of the other vehicle 3B is the second lane, the travel counter is decremented.

[0158] <Case of maintaining>

[0159] In the case where the conditions of the SN ratio and the adjacent lane probability of the above operations (A) to (C) are not satisfied, or in the case where the connection state is extrapolated, the travel counter is maintained and is not changed.

[0160] Further, here, extrapolation indicates a state in which, although the condition that the target detected last time and the target detected this time are the same (that is, continuous) is not satisfied, the possibility that the travel state of the target detected last time can be estimated as the same target (that is, extrapolation) is high, as is known (for example, refer to Japanese Patent Application Publication No. 2020-12795).

[0161] <Case of clearing>

[0162] In the case of a newly detected target (that is, the other vehicle 3B), or in the case where the monitoring flag is changed from ON to OFF (that is, off), the value of the travel counter is reset (that is, made zero).

[0163] Thus, in the processing of the second lane travel counter operation, the SN ratio, the adjacent lane probability, and the like are used to set the value of the travel counter.

[0164] Further, in Figure 9In the middle, the difference (i.e., S-N) between the level of the signal based on the target (i.e., S) and the level of the noise (i.e., N), for example, voltage, is shown in the case where the other vehicle 3B is estimated to be traveling on the third lane or the second lane. Further, in the middle, S-N is written as SN. The Figure 9 Figure 9 The graph shown in the above Figure 6 corresponds to the graph shown in the above, SN is exemplified for the other vehicle 3B on the same longitudinal position.

[0165] <Alert Determination Processing>

[0166] Next, in S340, it is determined whether or not the third lane travel monitoring release condition is satisfied. Here, if the affirmative determination is made, S350 is entered, on the other hand, if the negative determination is made, S360 is entered.

[0167] The third lane travel monitoring release condition refers to a condition for determining whether or not to reset (i.e., OFF) the monitoring flag for the other vehicle 3B for which the monitoring flag is ON in relation to the above-mentioned prerequisite condition.

[0168] The third lane travel monitoring release condition is shown in Table 3 below.

[0169] Further, as shown in Table 3, as long as one of the release conditions is satisfied, it is determined that the monitoring release condition is satisfied, and the monitoring of the other vehicle 3 traveling on the third lane is released. By releasing the monitoring, the alert can be promptly issued as described later.

[0170] [Table 3]

[0171]

[0172] <Release Condition 1>

[0173] In the case where the other vehicle 3B is not traveling on the third lane, and the travel counter is above the prescribed counter threshold, it is determined that the monitoring release condition is satisfied.

[0174] In other words, in the case where the other vehicle 3B is not traveling on the third lane, and it is detected that the prescribed number of times (i.e., above the counter threshold) is traveling on the second lane, the other vehicle 3B has a high possibility of changing lanes from the third lane to the second lane, and the monitoring of the other vehicle 3B traveling on the third lane is released.

[0175] ​In detail, it is judged that the other vehicle 3B, which is the monitoring target that has traveled on the third lane, is not traveling on the third lane this time, based on the travel position (i.e., the smooth position) thereof. Also, based on the condition that the travel counter is above the prescribed counter threshold value, it is judged that the travel of the second lane can be stably checked. For this reason, it is judged that the other vehicle 3B merges from the third lane to the second lane.

[0176] Here, the counter threshold value is changed according to the SN threshold value described above. The reason for changing the counter threshold value like this is to judge the travel of the second lane with the same accuracy regardless of the magnitude of the disturbance that affects the detection accuracy of the radar device 5. Also, the SN threshold value is appropriately set, for example, according to the degree of disturbance. Also, the disturbance refers to an element that affects the detection accuracy of the target (i.e., the other vehicle 3B) due to the reflected wave that affects the radar device 5 in the environment outside the host vehicle 3A, and walls and the like can be cited as examples.

[0177] For example, as described later, the SN threshold value is set higher in the case of less disturbance, but in the case where the SN threshold value is higher like this, the counter threshold value is set to a lower value (e.g., 2). On the other hand, the SN threshold value is set lower in the case of greater disturbance, but in the case where the SN threshold value is lower like this (i.e., lower than in the case described above), the counter threshold value is set to a higher value (i.e., higher than the lower value described above, for example, 5).

[0178] The counter threshold value is set like this because, for example, in the case where the SN is low, it is considered that the checking accuracy of the radar device 5 is unstable, so the period for situation judgment is set longer than usual.

[0179] <Case of Release Condition 2>

[0180] In the case where the other vehicle 3B is not traveling on the third lane and the TTC is below 3 sec, it is judged that the monitoring release condition is satisfied. Also, here, the TTC refers to the collision prediction time until the other vehicle 3B collides with the host vehicle 3A in the case where the host vehicle 3A has made a lane change to the second lane, under the condition that the current relative speed and the like continue. This TTC can be found by dividing the inter-vehicle distance by the relative speed. Also, TTC is an abbreviation for Time to Collision.

[0181] In other words, in the case where the other vehicle 3B is not traveling on the third lane and there is a possibility of collision in a short time, the monitoring of the other vehicle 3B is released.

[0182] <Case of Release Condition 3>

[0183] In the absence of the third lane, it is determined that the monitoring release condition is satisfied.

[0184] As the absence of the third lane, for example, a case where the host vehicle 3A has performed a lane change to the second lane can be cited.

[0185] <Release Condition 4>

[0186] In the case where the past alarm flag of the target (i.e., the other vehicle 3B) is ON and the past monitoring flag of the target is OFF, it is determined that the monitoring release condition is satisfied.

[0187] Here, the past alarm flag being ON means that the target became an alarm object in the processing (e.g., the last time or the time before that, etc.) prior to this time becoming a monitoring object. Further, the alarm flag indicates a flag that is set in the case where a condition for issuing an alarm is satisfied.

[0188] Then, in S350, the monitoring flag is made OFF because the monitoring release condition is satisfied.

[0189] Further, in the case where the other vehicle 3B is traveling on the host lane, or in the case where the other vehicle 3B has been traveling on the second lane from the beginning, the other vehicle 3B that is the object of this time, i.e., the other vehicle 3B whose travel lane is changed from the third lane to the second lane. That is, such other vehicle 3B is outside the monitoring object from the beginning.

[0190] Next in S360, it is determined whether the alarm determination condition, i.e., whether the monitoring flag is OFF, is satisfied. Here, if a positive determination is made, S370 is entered, whereas if a negative determination is made, the present processing is temporarily ended.

[0191] In S370, the "alm final output" is made ON, i.e., the alarm flag is set, and the present processing is temporarily ended.

[0192] Further, in the case where the alarm flag is set as such (i.e., in the ON case), an alarm is issued by the alarm device 7.

[0193] Further, the above-described S300 to S370 processing is performed on all of the targets (i.e., the other vehicles 3B).

[0194] [1-4. Effects]

[0195] In the above-described first embodiment, the following action effects can be obtained.

[0196] (1a) The vehicle control device 9 of the present first embodiment can assist in the confirmation of the rear side of the host vehicle 3A in order to achieve safety at the time of a lane change of the host vehicle 3A.

[0197] The vehicle control device 9 has a position estimation section 21, an SN index calculation section 23, a lane determination section 25, and an alarm determination section 27.

[0198] With this configuration, in the present first embodiment, the lane in which the other vehicle 3B is traveling can be determined with good accuracy, so the alarm can be appropriately issued with respect to the other vehicle 3B traveling in a dead angle region or the like on the rear side of the host vehicle 3A.

[0199] In detail, in the case where the SN is large, the estimation accuracy of the lateral position is high, whereas in the case where the SN is small, the estimation accuracy of the lateral position is low. Therefore, in the case of determining the lane in which the other vehicle 3B is traveling, the determination is made by taking into account the magnitude of the SN ratio, so the determination of the lane in which the other vehicle 3B is traveling can be made more reliably.

[0200] Therefore, for example, in the case where the determination accuracy of the lane in which the other vehicle 3B is traveling is high, the alarm can be appropriately (for example, promptly) issued on the basis of the determination result. On the other hand, in the case where the determination accuracy of the lane in which the other vehicle 3B is traveling is low, for example, the determination accuracy of the lane in which the other vehicle 3B is traveling can be improved by further taking into account other conditions or the like (for example, by extending the determination time), and the alarm can be appropriately issued on the basis of the determination result.

[0201] In other words, the alarm can be appropriately issued (for example, at an appropriate timing) when the alarm should be issued, and the alarm can be suppressed from being issued arbitrarily in the case where the alarm does not need to be issued.

[0202] (1b) The vehicle control device 9 of the present first embodiment determines the lane in which the other vehicle 3B is traveling on the basis of a certain determination condition (i.e., a first determination condition) in the case where the SN ratio is higher than a prescribed SN threshold value. In addition, in the case where the SN ratio is equal to or lower than the prescribed SN threshold value, the determination of the lane in which the other vehicle 3B is traveling is made on the basis of a second determination condition in which other conditions (for example, a condition to extend the determination time or other conditions) are added to the first determination condition. Thus, the lane determination with high accuracy can be stably made. In other words, even in the case where the SN ratio varies, the determination accuracy can be ensured.

[0203] (1c) The vehicle control device 9 of the present first embodiment can determine whether or not the other vehicle 3B is traveling on the second lane on the basis of the magnitude of the SN ratio.

[0204] (1d) The vehicle control device 9 of the first embodiment can easily determine that the other vehicle 3B is traveling on the second lane as the SN ratio is higher, for example, as the counter threshold is lower, when determining the lane on which the other vehicle 3B is traveling after determining that the other vehicle 3B is traveling on the third lane. Thus, the lane determination with high precision can be stably performed.

[0205] (1e) The vehicle control device 9 of the first embodiment can update the counter value of the travel counter set for determining the lane on which the other vehicle 3B is traveling based on the SN threshold.

[0206] (1f) The vehicle control device 9 of the first embodiment can make the counter value of the travel counter easily increase as the SN ratio is higher. Thus, the reliability of the reflected wave is higher, the lane determination can be performed quickly, and an alarm can be issued quickly as needed.

[0207] (1g) The vehicle control device 9 of the first embodiment can open the monitoring flag for determining the other vehicle 3B as a monitoring target when estimating that the other vehicle 3B is traveling on the third lane based on the determination criterion for determining whether the other vehicle 3B is traveling on the third lane.

[0208] (1h) The vehicle control device 9 of the first embodiment can close the monitoring flag when determining that the other vehicle 3B has changed lanes to the second lane based on the determination criterion for determining that the other vehicle 3B has changed lanes from the third lane to the second lane. Further, an alarm can be issued to the other vehicle 3B for which the monitoring flag is closed in the case where there is a concern of collision with the host vehicle 3A.

[0209] (1i) The vehicle control device 9 of the first embodiment can close the monitoring flag when estimating that the third lane has become non-existent.

[0210] (1j) The vehicle control device 9 of the first embodiment can close the monitoring flag when estimating that the other vehicle 3B has changed lanes to the second lane based on the condition that the other vehicle 3B is not traveling on the third lane and the determination condition based on the SN threshold.

[0211] [1-5. Correspondence of statements]

[0212] In the relationship between the first embodiment and the present disclosure, the host vehicle 3A corresponds to the host vehicle, the other vehicle 3B corresponds to the other vehicle, the vehicle control device 9 corresponds to the vehicle control device, the position estimation section 21 corresponds to the position estimation section, the SN index calculation section 23 corresponds to the SN index calculation section, the lane determination section 25 corresponds to the lane determination section, and the alarm determination section 27 corresponds to the alarm determination section.

[0213] [2. Second Embodiment]

[0214] The basic configuration of the second embodiment is the same as that of the first embodiment, so the following mainly describes the points different from the first embodiment. Further, the same reference numerals as those of the first embodiment denote the same configuration, and the previous description is referred to.

[0215] In the present second embodiment, the SN threshold value is changed according to the lateral position difference between the target (i.e., the other vehicle 3B) and the wall, so the description is made centering on this point.

[0216] [2-1. Outline of Control]

[0217] First, the outline of the control of the second embodiment is described.

[0218] As shown in FIG. 8, in the case where there is a wall on the outer side of the second lane (i.e., the side away from the host vehicle 3A), there is a case where the running position of the other vehicle 3B is erroneously judged as running on the third lane due to the influence of the wall even when the other vehicle 3B is running on the outer lane in the second lane. Figure 10 In other words, there is a case where the running position of the other vehicle 3B is erroneously judged due to the variation (i.e., the disturbance) of the reflected wave caused by the wall.

[0219] Therefore, at the timing when it is determined that the running position of the other vehicle 3B has changed lanes to the second lane, the distance from the other vehicle 3B to the wall is found based on the lateral position of the other vehicle 3B and the lateral position of the wall. Further, in the case where this distance is smaller than a prescribed determination value (i.e., in the case where the wall is close), the SN threshold value is adjusted.

[0220] Specifically, in the case where the distance from the other vehicle 3B to the wall is short (i.e., in the case where the other vehicle 3B is close to the wall), the SN threshold value is lowered. For example, the SN threshold value is lowered by a prescribed dB from the value set therefor. For example, in the case where it is set to 45 dB therefor, the SN threshold value is lowered to change to 40 dB.

[0221] In detail, in the case where the other vehicle 3B is close to the wall, since the disturbance is large, the difference between the level of the disturbance (i.e., the noise) and the level of the signal becomes small, and the above-described running counter does not easily rise. Therefore, although the SN threshold value is lowered, since it is a state where the angle accuracy is poor due to the large disturbance, the counter threshold value is raised.

[0222] Here, the reason for raising the counter threshold value is because in the state where the angle accuracy is poor, the SN threshold value is lowered and the counting easily rises, so the determination time is lengthened and the determination accuracy is improved as much as possible.

[0223] In detail, in the case where the other vehicle 3B is close to the wall, since the disturbance is large, the difference between the level of the disturbance (i.e., the noise) and the level of the signal becomes small, and the above-described running counter does not easily rise. Therefore, although the SN threshold value is lowered, since it is a state where the angle accuracy is poor due to the large disturbance, the counter threshold value is raised.

[0224] Further, even in a case where the other vehicle 3B approaches the wall, in a case where the SN ratio is larger than a prescribed value, for example, the SN threshold S3 (for example, 35 dB), the vehicle is set as the angle-stable vehicle without changing the SN threshold.

[0225] Further, as described above, in a case where it is determined that the other vehicle 3B is traveling on the second lane, the above monitoring is released.

[0226] Further, Figure 11 A case where there is a wall on the outer side of the third lane is shown. Further, the same applies in a case where there is no wall.

[0227] Here, in a case where it is determined that the other vehicle 3B is traveling on the inner side of the third lane and has made a lane change to the second lane, at this timing, the distance from the other vehicle 3B to the wall is calculated based on the lateral position of the other vehicle 3B and the lateral position of the wall. Further, in a case where this distance is equal to or greater than a prescribed determination value (i.e., in a case where the wall is far away), the SN threshold is adjusted.

[0228] Specifically, in a case where the other vehicle 3B is far away from the wall, the SN threshold is increased. For example, the SN threshold is made higher than the value set previously by a prescribed dB.

[0229] In detail, in a case where the other vehicle 3B is far away from the wall, the interference is small, so the difference between the level of the interference (i.e., noise) and the level of the signal increases, and the travel counter is likely to rise. Therefore, although the SN threshold is increased, since it is a state where the interference is small and the angle accuracy is good, the counter threshold is decreased.

[0230] Here, the reason for decreasing the counter threshold is because since the condition of the SN threshold (i.e., the reliability of the data is high) is satisfied in a state where the SN threshold is increased, it is desired to shorten the determination time and determine as an alarm target as early as possible.

[0231] Further, even in a case where the other vehicle 3B is far away from the wall, in a case where the SN ratio is equal to or less than a prescribed value (for example, S3), the vehicle is set as the angle-unstable vehicle, and the SN threshold is decreased compared to before the change.

[0232] [2-2. Processing of control]

[0233] Next, the processing of the control of the second embodiment will be described based on Figure 12 and Table 4.

[0234] This processing is processing for adjusting the travel counter by changing the SN threshold used in S330 described above according to the distance from the other vehicle 3B to the wall. Figure 8 ​

[0235] As Figure 12 shown in the flowchart, in S400, it is determined whether or not a threshold value change condition for changing the SN threshold value is satisfied. For example, it is determined whether or not a condition that the other vehicle 3B is not traveling on the third lane is satisfied. If affirmative determination is made, the process proceeds to S410, whereas if negative determination is made, the process is temporarily ended.

[0236] In S410, the distance from the other vehicle 3B to the wall is calculated.

[0237] Next, in S420, determination of the wall distance condition A is made. In other words, determination is made as to whether or not the distance from the other vehicle 3B to the wall (i.e., the wall distance) is less than 7 m or is 7 m or more. If it is determined that it is less than 7 m, the process proceeds to S480, whereas if it is determined that it is 7 m or more, the process proceeds to S430.

[0238] In S430, determination of the SN ratio condition C is made. In other words, determination is made as to whether or not the SN ratio is greater than 35 dB or is 35 dB or less. If it is determined that it is greater than 35 dB, the process proceeds to S460, whereas if it is determined that it is 35 dB or less, the process proceeds to S440.

[0239] In S440, the SN threshold value is lowered.

[0240] Next, in S450, the counter threshold value is set to 4, and the process is temporarily ended.

[0241] On the other hand, in S460 described above, the SN threshold value is raised.

[0242] Next, in S470, the counter threshold value is set to 2, and the process is temporarily ended.

[0243] In S480 entered from S420 described above in which it is determined that the wall distance is less than 7 m, determination of the wall distance condition B is made. In other words, determination is made as to whether or not the wall distance is greater than 3.5 m or is 3.5 m or less. If it is determined that it is greater than 3.5 m, the process proceeds to S510, whereas if it is determined that it is 3.5 m or less, the process proceeds to S490.

[0244] In S490, the SN threshold value is lowered.

[0245] In S500, the counter threshold value is set to 4, and the process is temporarily ended.

[0246] On the other hand, in the above S510, the determination of the SN ratio condition D is performed. In other words, the determination of whether the SN ratio is greater than 35 dB or is 35 dB or less is performed. Here, in the case where it is determined that the SN ratio is greater than 35 dB, S540 is entered, whereas in the case where it is determined that the SN ratio is 35 dB or less, S520 is entered.

[0247] In S520, the SN threshold value is lowered.

[0248] Next, in S530, the counter threshold value is set to 4, and the present processing is temporarily ended.

[0249] On the other hand, in the above S540, the counter threshold value is set to 2, and the present processing is temporarily ended.

[0250] Here, the above-described method of setting the SN threshold value and the counter threshold value is explained based on Table 4 below.

[0251] [Table 4]

[0252]

[0253] Even if the wall distance is 7 m or more and the influence of the interference is small, in the case where the SN ratio is 35 dB or less, it is considered that the difference between the level of the noise and the level of the signal is small. In this case, the travel counter does not easily increase, so the SN threshold value is lowered, but since the angle accuracy is poor, the counter threshold value is increased to 4, for example.

[0254] Even if the wall distance is 7 m or more and the influence of the interference is small, in the case where the SN ratio is greater than 35 dB, it is considered that the difference between the level of the noise and the level of the signal is large. In this case, the travel counter easily increases, so the SN threshold value is increased, and the counter threshold value is lowered to 2, for example.

[0255] In the case where the wall distance is 3.5 m or less and the influence of the interference is large, the SN threshold value is lowered, and the counter threshold value is increased to 4, for example.

[0256] In the case where the wall distance is less than 7 m and is greater than 3.5 m, the influence of the interference is considered to be moderate. In this case, in the case where the SN ratio is greater than 35 dB, the operation of the SN threshold value is not performed. At this time, the counter threshold value is maintained at 2, for example.

[0257] In the case where the wall distance is less than 7 m and is greater than 3.5 m, the influence of the interference is considered to be moderate. In this case, in the case where the SN ratio is 35 dB or less, it is considered that the difference between the level of the noise and the level of the signal is small. In this case, the travel counter does not easily increase, so the SN threshold value is lowered, but since the angle accuracy is poor, the counter threshold value is increased to 4, for example.

[0258] Further, the adjusted SN threshold value can be maintained, for example, until the target is lost, until monitoring is released, or until the TTC becomes 3 sec or less. Alternatively, the SN threshold value can be changed each time the operation is performed in each cycle.

[0259] [2-3. Effects]

[0260] (2a) The second embodiment has the same effects as the first embodiment.

[0261] (2b) The second embodiment changes the SN threshold value in accordance with the SN ratio in order to suppress (for example, remove) the influence of interference in the reflected wave of the radar wave.

[0262] In other words, the SN threshold value is changed in accordance with the lateral positional difference of the other vehicle 3B from the wall (that is, the distance from the other vehicle 3B to the wall). Specifically, the SN threshold value is reduced in the case where the lateral positional difference of the other vehicle 3B from the wall is small, as compared with the case where the lateral positional difference is large.

[0263] Thus, it is possible to reduce the influence of the variation in the reflected wave caused by the above-described lateral positional difference. Therefore, it is possible to determine the travel lane with stable accuracy regardless of the state of interference.

[0264] Specifically, it is possible to determine that the other vehicle 3B is traveling on the second travel lane with the same accuracy regardless of the magnitude of interference, by the above-described processing. As a result, it is possible to issue an alarm at an appropriate timing.

[0265] [3. Other Embodiments]

[0266] The embodiments of the present disclosure have been described above, but the present disclosure is not limited to the above-described embodiments, and various modifications can be made to implement the present disclosure.

[0267] (3a) In the present disclosure, the ratio (that is, S / N) of the level of the signal (that is, S) of the target to the level of the noise (that is, N) is used as the SN index, but the difference (that is, S-N) between the level of the signal and the level of the noise can also be used. In other words, various indexes that represent the relationship of the level of the signal with respect to the level of the noise can be adopted as the SN index.

[0268] (3b) In addition, the SN threshold value can be changed in accordance with various interference other than the wall (for example, natural environment, etc.), as in the above-described first embodiment. Further, the SN threshold value can be changed in accordance with the TTC. For example, the SN threshold value can be increased in the case where the TTC is 5 sec or more.

[0269] (3c) The vehicle control device and the method thereof according to the present disclosure can also be realized by a special computer provided by a processor configured to execute one or more functions embodied by a computer program and a memory.

[0270] Alternatively, the vehicle control device and the method thereof according to the present disclosure can also be realized by a special computer provided by a processor configured by one or more special hardware logic circuits.

[0271] Alternatively, the vehicle control device and the method thereof according to the present disclosure can also be realized by one or more special computers configured by a combination of a processor programmed to execute one or more functions and a memory and a processor configured by one or more hardware logic circuits.

[0272] In addition, the computer program can also be stored as instructions executable by a computer in a non-transitory tangible recording medium readable by the computer. The method of realizing the functions of each part included in the control section does not necessarily include software, and all the functions thereof can be realized using one or more hardware.

[0273] (3d) One of the constituent elements in the above-described embodiments can realize a plurality of functions possessed by a plurality of constituent elements, or one of the constituent elements can realize one function possessed by a plurality of constituent elements. In addition, one of the constituent elements can realize a plurality of functions possessed by a plurality of constituent elements, or one of the constituent elements can realize one function realized by a plurality of constituent elements. In addition, a part of the configuration of the above-described embodiments can be omitted. In addition, at least a part of the configuration of the above-described embodiments can be added to or replaced with the configuration of another of the above-described embodiments.

[0274] (3e) In addition to the above-described vehicle control device, the present disclosure can also be realized in various manners such as a system including the vehicle control device as a constituent element, a program for causing a computer of the vehicle control device to function, a non-transitory tangible recording medium such as a semiconductor memory in which the program is recorded, a control method, and the like.

Claims

1. A vehicle control device that uses radar waves to assist in the confirmation of the rear side of the vehicle, wherein, The aforementioned vehicle control device includes: The position estimation unit is configured to estimate the lateral position of other vehicles in the width direction of the road based on the reflected waves of the radar waves irradiated from the vehicle to the surrounding area. The SN index calculation unit is configured to calculate an SN index, which represents the relationship between the signal level in the reflected wave and the noise level, based on the reflected wave of the radar wave irradiated from the vehicle to the surrounding area. The lane determination unit is configured to determine the lane in which the other vehicle is traveling based on the SN index calculated by the SN index calculation unit when determining the lane in which the other vehicle is traveling based on the information of the lateral position of the other vehicle estimated by the position estimation unit. as well as The alarm determination unit is configured to determine, based on the determination result obtained by the lane determination unit, whether the conditions for issuing an alarm are met for the other vehicles.

2. The vehicle control device according to claim 1, wherein, The configuration is as follows: when the SN index is higher than the specified value, the lane in which the other vehicle is traveling is determined based on the first determination condition; when the SN index is lower than the specified value, the lane in which the other vehicle is traveling is determined based on the second determination condition, which adds other conditions to the first determination condition.

3. The vehicle control device according to claim 1, wherein, The configuration is as follows: based on the above SN index, it is determined whether the other vehicles are traveling in the second lane adjacent to the first lane in which the vehicle is traveling.

4. The vehicle control device according to claim 2, wherein, The configuration is as follows: based on the above SN index, it is determined whether the other vehicles are traveling in the second lane adjacent to the first lane in which the vehicle is traveling.

5. The vehicle control device according to claim 1, wherein, The composition is as follows: In the case where the lane in which the vehicle travels is designated as the first driving lane, the lane adjacent to the first driving lane is designated as the second driving lane, and the lane adjacent to the second driving lane but on the opposite side of the first driving lane is designated as the third driving lane, When determining the lane in which the other vehicle is traveling after determining that it is traveling in the third lane, the higher the SN index, the easier it is to determine that the other vehicle is traveling in the second lane.

6. The vehicle control device according to claim 2, wherein, The composition is as follows: In the case where the lane in which the vehicle travels is designated as the first driving lane, the lane adjacent to the first driving lane is designated as the second driving lane, and the lane adjacent to the second driving lane but on the opposite side of the first driving lane is designated as the third driving lane, When determining the lane in which the other vehicle is traveling after determining that it is traveling in the third lane, the higher the SN index, the easier it is to determine that the other vehicle is traveling in the second lane.

7. The vehicle control device according to claim 3, wherein, The composition is as follows: In the case where the lane in which the vehicle travels is designated as the first driving lane, the lane adjacent to the first driving lane is designated as the second driving lane, and the lane adjacent to the second driving lane but on the opposite side of the first driving lane is designated as the third driving lane, When determining the lane in which the other vehicle is traveling after determining that it is traveling in the third lane, the higher the SN index, the easier it is to determine that the other vehicle is traveling in the second lane.

8. The vehicle control device according to claim 4, wherein, The composition is as follows: In the case where the lane in which the vehicle travels is designated as the first driving lane, the lane adjacent to the first driving lane is designated as the second driving lane, and the lane adjacent to the second driving lane but on the opposite side of the first driving lane is designated as the third driving lane, When determining the lane in which the other vehicle is traveling after determining that it is traveling in the third lane, the higher the SN index, the easier it is to determine that the other vehicle is traveling in the second lane.

9. The vehicle control device according to claim 1, wherein, It is configured to have an SN threshold for judging the level of the above-mentioned SN index, and based on the above-mentioned SN threshold, update the counter value of the driving counter set for judging the lane in which the above-mentioned other vehicles are driving.

10. The vehicle control device according to claim 2, wherein, It is configured to have an SN threshold for judging the level of the above-mentioned SN index, and based on the above-mentioned SN threshold, update the counter value of the driving counter set for judging the lane in which the above-mentioned other vehicles are driving.

11. The vehicle control device according to claim 3, wherein, It is configured to have an SN threshold for judging the level of the above-mentioned SN index, and based on the above-mentioned SN threshold, update the counter value of the driving counter set for judging the lane in which the above-mentioned other vehicles are driving.

12. The vehicle control device according to claim 4, wherein, It is configured to have an SN threshold for judging the level of the above-mentioned SN index, and based on the above-mentioned SN threshold, update the counter value of the driving counter set for judging the lane in which the above-mentioned other vehicles are driving.

13. The vehicle control device according to claim 5, wherein, It is configured to have an SN threshold for judging the level of the above-mentioned SN index, and based on the above-mentioned SN threshold, update the counter value of the driving counter set for judging the lane in which the above-mentioned other vehicles are driving.

14. The vehicle control device according to claim 6, wherein, It is configured to have an SN threshold for judging the level of the above-mentioned SN index, and based on the above-mentioned SN threshold, update the counter value of the driving counter set for judging the lane in which the above-mentioned other vehicles are driving.

15. The vehicle control device according to claim 7, wherein, It is configured to have an SN threshold for judging the level of the above-mentioned SN index, and based on the above-mentioned SN threshold, update the counter value of the driving counter set for judging the lane in which the above-mentioned other vehicles are driving.

16. The vehicle control device according to claim 8, wherein, It is configured to have an SN threshold for judging the level of the above-mentioned SN index, and based on the above-mentioned SN threshold, update the counter value of the driving counter set for judging the lane in which the above-mentioned other vehicles are driving.

17. The vehicle control device according to claim 9, wherein, The higher the SN index mentioned above, the easier it is for the counter value of the driving counter to rise.

18. The vehicle control device according to claim 10, wherein, The higher the SN index mentioned above, the easier it is for the counter value of the driving counter to rise.

19. The vehicle control device according to claim 11, wherein, The higher the SN index mentioned above, the easier it is for the counter value of the driving counter to rise.

20. The vehicle control device according to claim 12, wherein, The higher the SN index mentioned above, the easier it is for the counter value of the driving counter to rise.

21. The vehicle control device according to claim 13, wherein, The higher the SN index mentioned above, the easier it is for the counter value of the driving counter to rise.

22. The vehicle control device according to claim 14, wherein, The higher the SN index mentioned above, the easier it is for the counter value of the driving counter to rise.

23. The vehicle control device according to claim 15, wherein, The higher the SN index mentioned above, the easier it is for the counter value of the driving counter to rise.

24. The vehicle control device according to claim 16, wherein, The higher the SN index mentioned above, the easier it is for the counter value of the driving counter to rise.

25. The vehicle control device according to any one of claims 1 to 24, wherein, The composition is as follows: In the case where the lane in which the vehicle travels is designated as the first driving lane, the lane adjacent to the first driving lane is designated as the second driving lane, and the lane adjacent to the second driving lane but on the opposite side of the first driving lane is designated as the third driving lane, If, based on the determination criteria for whether the aforementioned other vehicles are traveling in the aforementioned third lane, it is estimated that the aforementioned other vehicles are traveling in the aforementioned third lane, the monitoring sign for the aforementioned other vehicles used to identify the monitoring target is activated.

26. The vehicle control device according to claim 25, wherein, The configuration is as follows: if, based on the determination criterion that the other vehicle has changed lanes from the third lane to the second lane, the monitoring sign is turned off.

27. The vehicle control device according to claim 25, wherein, The configuration is as follows: if it is estimated that the aforementioned third lane no longer exists, the aforementioned monitoring sign is turned off.

28. The vehicle control device according to claim 25, wherein, The configuration includes an SN threshold for judging the level of the aforementioned SN index, and when it is estimated that the aforementioned other vehicles have changed lanes to the aforementioned second lane based on the condition that the aforementioned other vehicles are not traveling in the aforementioned third lane and the judgment condition based on the aforementioned SN threshold, the aforementioned monitoring sign is turned off.

29. The vehicle control device according to any one of claims 1 to 24 and 26 to 28, wherein, The configuration includes an SN threshold for judging the level of the aforementioned SN index, and the SN threshold is adjusted according to the aforementioned SN index in order to suppress the influence of interference in the aforementioned reflected waves of the aforementioned radar waves.

30. The vehicle control device according to claim 25, wherein, The configuration includes an SN threshold for judging the level of the aforementioned SN index, and the SN threshold is adjusted according to the aforementioned SN index in order to suppress the influence of interference in the aforementioned reflected waves of the aforementioned radar waves.

31. The vehicle control device according to claim 29, wherein, The configuration is as follows: the SN threshold is changed based on the lateral position difference between the other vehicles and the wall.

32. The vehicle control device according to claim 30, wherein, The configuration is as follows: the SN threshold is changed based on the lateral position difference between the other vehicles and the wall.

33. The vehicle control device according to claim 31, wherein, The configuration is as follows: when the lateral position difference between the other vehicles and the wall is smaller than the judgment value, the SN threshold is reduced compared to the case where the difference is larger than the judgment value.

34. The vehicle control device according to claim 32, wherein, The configuration is as follows: when the lateral position difference between the other vehicles and the wall is smaller than the judgment value, the SN threshold is reduced compared to the case where the difference is larger than the judgment value.

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