Driving assistance device

Abstract

Driving assistance device comprising: a deviation probability value maintenance device (44) which is configured such that it receives a deviation probability value which represents a probability degree of a deviation of one's own vehicle (8) from a lane; a maintenance device (38) for a relative position relationship, which is configured such that it detects another vehicle (36) which is positioned diagonally behind the own vehicle (8), and maintains a relative position relationship between the other vehicle (36) and the own vehicle (8); a support execution device (20) configured to perform a track deviation prevention support; and a support control device (46) configured to control the support execution device (20) to execute the track deviation prevention support when the deviation probability value obtained by the deviation probability value maintenance device (44) is greater than or equal to a threshold value, wherein the support control device (46) has a threshold determination device (46) which is configured such that it determines the threshold as a smaller value when the relative position relationship maintained by the maintenance device (38) for a relative position relationship corresponds to a set relationship, compared to when the relative position relationship does not correspond to the set relationship, wherein the set relationship corresponds to a relationship in which, in the event of a deviation of the own vehicle (8) from the lane, there is a probability of collision of the own vehicle (8) with the other vehicle (36), the support control device (46) further comprises: a first support control device (46) configured to determine the threshold as a first threshold when the relative position relationship does not correspond to the set relationship, and to control the support execution device (20) when the deviation probability value is greater than or equal to the first threshold; and a second support control device (46) configured to determine the threshold as a second threshold that is smaller than the first threshold when the relative position relationship corresponds to the set relationship, and to control the support execution device (20) when the deviation probability value is greater than or equal to the second threshold, wherein the maintenance device (38) for a relative position relationship has an inter-vehicle distance maintenance device (38) which is configured such that it maintains an inter-vehicle distance (L) as the relative position relationship, the driving assistance device includes: an indicator (20, 34); and an inter-vehicle distance-dependent display activation means (39, 46) which is configured such that it activates the indicator (20, 34) when the inter-vehicle distance (L) maintained by the inter-vehicle distance maintenance device (38) is less than or equal to a first inter-vehicle distance (Lth1), wherein the second support control device (46) has an inter-vehicle distance-dependent support control device (46) which is configured to determine that the relative position relationship corresponds to the set relationship and controls the support execution device (20) when the deviation probability value is greater than or equal to the second threshold value and when the inter-vehicle distance (L) is less than or equal to a second inter-vehicle distance (Lth2) which is less than the first inter-vehicle distance (Lth1), and wherein the inter-vehicle distance-dependent support control device (46) is configured such that it determines that the relative position relationship corresponds to the set relationship and controls the support execution device (20) when a condition in which the inter-vehicle distance (L) is less than or equal to the second inter-vehicle distance (Lth2) has lasted for a time longer than or equal to a set parallel travel time (T0).

Description

background

[0001] The present disclosure relates to a driving assistance device which is configured to assist driving.

[0002] JP 2006-331304 A and JP 2007-168662 A disclose driving assistance devices configured to help prevent a vehicle from deviating from its lane. In the driving assistance device disclosed in JP 2006-331304 A, an alarm is triggered if there is a probability that the vehicle will deviate from its lane and the steering angle of the steering wheel is less than or equal to a threshold value. This threshold value is modified based on the vehicle's surroundings. For example, if an object is located in front of the vehicle, which in most cases will attempt to avoid the object, the device determines that there is a need for the vehicle to deviate from its lane.The threshold is set at a lower value when it is determined that there is a need for the vehicle to deviate from its lane, compared to when it is determined that there is no need for the vehicle to deviate from its lane. This setting makes it difficult to issue unnecessary warnings.

[0003] JP 2008-171082 A and JP 2015-130098 A disclose driver assistance devices configured to: detect another vehicle positioned diagonally behind the driver's own vehicle; obtain an inter-vehicle distance and a collision estimation time as a relative positional relationship between the driver's own vehicle and the other vehicle; and, if the inter-vehicle distance is less than or equal to a set inter-vehicle distance and / or if the collision estimation time is less than or equal to a set estimation time, inform a driver of this situation.

[0004] Furthermore, US patent 2015 / 0183430A1 discloses a lane keeping assist system that uses a front sensor to determine the lane position of a host vehicle and to detect oncoming vehicles. Rear side sensors monitor the lateral blind spots of the host vehicle as well as vehicles in adjacent lanes approaching from behind. A control system combines the information provided by these sensors and executes integrated programs to provide lane keeping assistance and lane departure warning.

[0005] German patent DE 10 2005 025 387 A1 discloses a method for warning the driver and / or actively intervening in the vehicle's dynamics if a lane departure is imminent. Lane markings in the vicinity of the vehicle are detected by means of an image sensor, whereby at least one safety distance from a lane marking is specified, and if this distance is breached, a driver warning and / or intervention in the vehicle's dynamics occurs. This safety distance is selected depending on the traffic situation, the driver's behavior, or a combination thereof. For this purpose, a safety value is read from a storage device in which traffic-specific and / or driving-behavior-specific predefined values ​​are stored.

[0006] DE 199 21 449 C1 discloses a guidance aid for a vehicle changing lanes, comprising an object detection unit for detecting objects in a side rear area of ​​the vehicle, a warning indicator unit, and an evaluation unit. Using signals supplied to it by the object detection unit, the evaluation unit determines whether an object is located in the blind spot section of the monitored side rear area or whether an object is moving forward at a higher speed than the vehicle in a section of the monitored side rear area extending beyond the blind spot section. If the answer is yes, the evaluation unit activates the warning indicator unit to issue a warning signal if it also detects a lane change request belonging to the corresponding side area.A position detection device is provided that determines the vehicle's path data and road geometry data in order to determine the position of the vehicle on the road, and if the object detection unit detects a following vehicle in the side and rear area, a position assignment of the following vehicle relative to the road is determined according to the route traveled recorded with the position detection device and the road geometry.

[0007] Furthermore, DE 10 2010 063 420 A1 discloses a driver assistance system with a sensor arrangement for detecting the distance between the vehicle and a foreign object and with an electronic control unit for activating vehicle-internal actuators depending on information obtained from signals of the sensor arrangement. The sensor arrangement comprises at least one sensor located on a longitudinal side of the vehicle and capable of measuring the distance of a foreign object from this longitudinal side. The control unit includes a program module that, during forward travel, can issue a warning to the driver via a connection to at least one corresponding actuator if the measured distance of a foreign object to the longitudinal side of the vehicle is less than a predefined safety distance. Summary

[0008] Accordingly, one aspect of the disclosure relates to a technology for increasing opportunities or possibilities for implementing lane departure prevention support as a driving aid to improve safety.

[0009] The aforementioned problems and the resulting task are solved by the subject matter of claim 1. Advantageous embodiments of the invention are the subject matter of the dependent claims that follow.

[0010] One aspect of the disclosure relates to a driving assistance device configured such that it: performs lane departure prevention assistance as driving assistance when a deviation probability value, which corresponds to a value representing a probability degree of a deviation of the vehicle from a lane, is greater than or equal to a threshold; and performs lane departure prevention assistance when a relative positional relationship between the vehicle and another vehicle positioned diagonally behind the vehicle corresponds to a set relationship, even in the case where the deviation probability value is less than the threshold.The configured relationship can, for example, correspond to a relationship where there is a high probability of collision between the vehicle and the other vehicle if the vehicle deviates from its lane. Therefore, if the relative position relationship between the vehicle and the other vehicle matches the configured relationship, lane departure prevention support will be activated in some cases, even if the probability of deviation is less than the threshold. This configuration increases the opportunities for lane departure prevention support to be activated, leading to improved safety. Brief description of the illustrations

[0011] The tasks, features, advantages, and technical and industrial significance of the present disclosure will become more understandable by reading the following detailed description of the embodiment when considered in conjunction with the accompanying illustrations, which: Fig. 1 is a view that represents a relative positional relationship between one's own vehicle and another vehicle, wherein a driving assistance device according to one embodiment is installed on the own vehicle; Fig. 2 is a block diagram that conceptually represents the driving assistance device; Fig. 3 is a flowchart which represents a Lane Deviation Alarm (LDA) program that is stored in a memory of an LDA unit of the driving assistance device; Fig. 4 is a view which represents a relative positional relationship between the vehicle and a lane boundary; Fig. 5 is a flowchart representing a Blind Spot Monitoring (BSM) / Lane Change Assistance (LCA) program stored in a memory of a BSM / LCA unit of the driver assistance device; and Fig. 6 is a flowchart which represents a license plate setting program stored in the memory of the BSM / LCA unit. Detailed description of the embodiment

[0012] One embodiment is described below with reference to the illustrations.

[0013] Fig. 2 represents a driving assistance device according to the present embodiment. The driving assistance device is in a Fig. The driver assistance device is installed in the vehicle 8 shown in Figure 1. It comprises a Lane Deviation Alarm (LDA) unit 10, Blind Spot Monitoring (BSM) / Lane Change Alarm (LCA) units 12, a steering device 14, a vehicle speed maintenance device 15, and a turn signal / indicator switch 16. A user turns the turn signal switch 16 on or off when the direction of travel of the vehicle 8 is changed. The steering device 14 comprises: an electric power steering device 20, as an example of an assistance execution device, configured to use an output from an electric motor 18 to assist a driver in a steering operation; and a control device 22, which is primarily computer-based.The electric power steering device 20 is configured such that the vehicle's wheels are rotated or steered by an actuating force applied by the driver to a steering actuating element 24 and the output of the electric motor 18. The control device 22 controls the electric motor 18 to control its output.

[0014] The BSM / LCA units 12 are mounted on the rear section of the vehicle 8 and on the opposite sections in a lateral direction of the vehicle 8. Each BSM / LCA unit 12 comprises a millimeter-wave radar 30 and a control device 32, which is primarily computer-based. LED lights 34, located on the right and left door mirrors 33, are connected to the respective BSM / LCA units 12. A BSM / LCA switch 35 is also connected to the BSM / LCA units 12. The driver activates the BSM / LCA switch 35 when BSM / LCA control is permitted.

[0015] The millimeter-wave radar 30 comprises a sensor 37 and a maintenance device 38 for a relative position relationship. The transmitter 37 comprises: an emitter configured to emit millimeter waves; and a receiver configured to receive reflected waves. The maintenance device 38 for a relative position relationship detects another vehicle 36, which is in an area Rm (see Fig. 1) is arranged based on the reflected waves detected by the sensor 37. The maintenance device 38 for a relative position relationship maintains a relative position relationship between the detected vehicle 36 and the vehicle 8 itself. The area Rm comprises: an area (an area R1, as in Fig. 1), which is arranged on one side of the rear section of the own vehicle 8 in its lateral direction (i.e., a transverse direction); and an area (an area R2) which is arranged on the rear of the own vehicle 8 and on one side of the own vehicle 8 in the lateral direction (hereinafter this may be referred to as the "area which is arranged diagonally behind the own vehicle 8"). That is, the millimeter-wave radar 30 enables the detection of the vehicle 36 traveling in an adjacent lane, for example, at a position that is diagonally behind the own vehicle 8. The maintenance device 38 for a relative position relationship receives, for example, a collision estimate time (time until collision) TTC and an inter-vehicle distance L as a relative position relationship between the detected vehicle 36 and the own vehicle 8.Both the inter-vehicle distance L and the collision estimation time TTC are obtained under the assumption that vehicle 8 and vehicle 36 are traveling in the same lane. The collision estimation time TTC is obtained by dividing the inter-vehicle distance L by a relative speed, and this can also be referred to as a "closing-up estimation time".

[0016] Each of the control devices 32 is primarily computer-based and comprises an execution device, a memory, an input / output device, and a timer, which are not shown. The control device 32 includes an LED control device 39, which is configured to control an LED light 34 to illuminate or flash based on the inter-vehicle distance L and the collision estimation time TTC, which are maintained by the maintenance device 38 for a relative position relationship. In the present embodiment, if the inter-vehicle distance L between the detected vehicle 36 and the vehicle 8 is less than or equal to a first inter-vehicle distance Lth1, in other words, if at least a section or part of the vehicle 36 is in an area R3 in Fig. 1 (which corresponds to a blind spot for the driver), the LED light 34, which is provided at one of the door mirrors 33 that is closer to the vehicle 36 than the other, is controlled to flash when the turn signal switch 16 is on, and it is controlled to remain lit when the turn signal switch 16 is off. This actuation may hereinafter be referred to as "the LED light 34 is lit or flashing". This control may hereinafter be referred to as "BSM control". In the case where the detected vehicle 36 is located in area R4 behind area R3, but is traveling at a high relative speed, and the collision estimation time TTC is less than or equal to a first estimation time Tth1, the LED light 34 provided at one of the door mirrors 33 that is closer to the vehicle 36 is controlled to remain lit or flash. This control system can be referred to as "LCA control".In the present embodiment, each of the LED lights 34 corresponds to an example of an indicator or a display device, and both the illumination and the flashing of the LED light 34 correspond to an example of a display as a driving aid.

[0017] In the present embodiment, at each time a set time period has elapsed, a step is executed according to the flowchart in Fig. The BSM / LCA program shown in Figure 5 is executed. At step S1, it is determined whether the BSM / LCA switch 35 is ON. If the BSM / LCA switch 35 is OFF, the processing operations at S2 and the subsequent steps are not performed. If the BSM / LCA switch 35 is ON, step S2 determines whether each of the BSM / LCA units 12 has detected the vehicle 36 within the area Rm. If the vehicle 36 has been detected, step S3 obtains the inter-vehicle distance L, and step S4 determines whether the inter-vehicle distance L is less than or equal to the first inter-vehicle distance Lth1. If S4 is positive (Yes), step S5 determines whether the direction indicator switch 16 is ON. If the direction indicator switch 16 is OFF, step S6 controls the LED light 34 from one of the door mirrors 33 located closer to the lane in which the vehicle 36 is traveling to illuminate. When the direction indicator switch 16 is on, the LED light 34 at S7 is controlled to flash.In contrast, if the inter-vehicle distance L is greater than the initial inter-vehicle distance Lth1, the collision estimation time TTC is obtained at S8, and at S9 it is determined whether the collision estimation time TTC is less than, shorter than, or equal to the initial estimation time Tth1. If a positive result (Yes) is obtained at S9, the LED light 34 is controlled at S5 to S7 to illuminate or flash.

[0018] The LDA unit 10 comprises a front camera 40 and a control device 42, which is primarily computer-based. An LDA switch 48 is connected to the LDA unit 10. The LDA switch 48 is activated when the driver enables the LDA. The front camera 40 is installed in the upper section of the windshield of the vehicle 8. The front camera 40 can capture an image of an area Rf (see Fig. 1) record, which lies directly and diagonally in front of the vehicle 8. The control device 42 is mainly computer-based and comprises an execution device, a memory, an input / output device, and a timer, which are not shown. The control device 42 further comprises a deviation probability value maintenance device 44 and an auxiliary control device 46. The deviation probability value maintenance device 44 is configured such that it receives a deviation probability value corresponding to a value representing the probability of the vehicle 8 deviating from its lane. In the present embodiment, the deviation probability value maintenance device 44 receives, as shown in Fig. As shown in Figure 4, a close-range distance D is used as the deviation probability value. The close-range distance D corresponds to the distance between a lane boundary (a lane line) A and a reference point Pv, which corresponds to a predetermined point on the vehicle 8. The lane boundary A is identified by processing the image captured by the front camera 40, and the distance between the reference point Pv of the vehicle 8 and the lane boundary A in the lateral direction of the lane is obtained, for example, as the close-range distance D. The deviation probability value is set to a higher value when the close-range distance D is short compared to when the close-range distance D is long.

[0019] It should be noted that the deviation probability value conservation device 44 can obtain a lateral deviation amount Δw as the deviation probability value. The lateral deviation amount Δw corresponds to the magnitude of a deviation of the reference point Pv of the own vehicle 8 from a centerline C of the lane in the transverse direction. The lateral deviation amount Δw is greater when the short distance D is short compared to when the short distance D is long. For example, if the width of the lane on which the own vehicle 8 travels is defined as W (that is, the distance between lane lines), the lateral deviation amount Δw can be obtained by subtracting the short distance D from half the width W of the lane (Δw = W / 2 - D).The lateral deviation Δw and the close-range distance D correspond to each other in this way, and the deviation of the vehicle 8 in the lane in the lateral direction can be determined based on the close-range distance D. Therefore, it is possible to consider the close-range distance D as an example of a lateral deviation. The probability of deviation is higher when the lateral deviation Δw is large compared to when the lateral deviation Δw is small. The reference point can be located near a headlight of the vehicle 8.

[0020] The support control device 46 is configured to output a value for instructing the control of the electric motor 18 of the electric power steering device 20, for example, based on the obtained deviation probability value. In the present embodiment, the electric motor 18 applies a force directed in a direction that prevents the vehicle 8 from deviating from its lane. For example, the electric motor 18 applies a force sufficient to slightly rotate or steer the wheels. This application of force assists the driver in operating the steering control element 24 in the direction that prevents the vehicle 8 from deviating from its lane. In other words, lane departure prevention assistance is provided as a form of driving assistance. This control is referred to as "LDA control".It should be noted that the magnitude of the force applied by the electric motor 18 may be greater in the case where the short distance D is short than in the case where the short distance D is long.

[0021] The control devices 22, 32, 42 and other similar devices are interconnected via a control unit network (CAN) 50 to enable communication. Devices connected to the CAN 50 also include, for example, the vehicle speed maintenance device 15 and the direction indicator switch 16. The vehicle speed maintenance device 15 includes wheel speed sensors 56, which are provided accordingly at the front left and right and the rear left and right wheels. The vehicle speed maintenance device 15 is configured to maintain the vehicle speed 8 based on the wheel speed of the four wheels.

[0022] For the own vehicle 8, which is configured as described above, the LDA control is executed in the case where the deviation probability value of the own vehicle 8 is greater than or equal to a first threshold value, and the LDA control is also executed in the case where the BSM / LCA unit 12 has detected that the relative position relationship between the own vehicle 8 and the vehicle 36 arranged diagonally behind the own vehicle 8 corresponds to a set relationship, even if the deviation probability value is less than the first threshold value.

[0023] In particular, if the short distance D is less than or equal to a first short distance Dth1, it is determined that the deviation probability value is greater than or equal to the first threshold, and the LDA control is executed. The first short distance Dth1 can, for example, be set to a distance between the vehicle 8 and the lane boundary A, where this distance is short enough to account for a high need to execute the lane deviation prevention support.

[0024] In the case where the close-range distance D is greater than the first close-range distance Dth1 and less than or equal to a second close-range distance Dth2, the deviation probability value is determined to be greater than or equal to a second threshold value that is less than the first threshold value. In this case, the LDA control is executed in case (a) where a state in which the inter-vehicle distance L between the own vehicle 8 and the vehicle 36 arranged diagonally behind the own vehicle 8 is less than or equal to a second inter-vehicle distance Lth2, which is less than the first inter-vehicle distance Lth1, has lasted longer than or equal to a set parallel travel time T0; in other words, in the case where a state in which at least part of the vehicle 36 is arranged in an area R5 has lasted longer than or equal to the set parallel travel time T0; or in case (b) wherein which the collision estimation time TTC is shorter than or equal to a second estimation time Tth2, which is shorter than the first estimation time Tth1; in other words, in the case where vehicle 36 is located in area R6, but the speed of vehicle 36 is high relative to the own vehicle 8. In the present embodiment, relationship (a) or relationship (b) corresponds to the set relationship. The set relationship may, for example, correspond to a relationship in which there is a high probability of a collision between the own vehicle 8 and vehicle 36 if the own vehicle 8 deviates from the lane. It should be noted that the second short distance Dth2 may be set to a distance that allows for the detection of a deviation of the own vehicle 8 in the lateral direction. This is because, in the case,in which the own vehicle 8 travels essentially along the center line C of the lane, even in the case where the relative positional relationship between the own vehicle 8 and the vehicle 36 corresponds to the set relationship, there is a low need to execute the lane deviation prevention support.

[0025] It is possible to consider that LDA control is executed when the deviation probability value is greater than or equal to the second threshold, and BSM or LCA controls should be executed. However, some drivers feel that lane departure warning is applied too early if it is applied when the inter-vehicle distance L between vehicle 36 and their own vehicle 8 becomes less than or equal to the first inter-vehicle distance Lth1, in cases where the deviation probability value is less than the first threshold.Furthermore, some drivers feel that lane changes are possible even when vehicle 36 is located, for example, in area R5, and that the lane departure warning system is disruptive when the speed of their own vehicle 8 is higher than that of vehicle 36. To solve this problem, in the present embodiment, the LDA control is implemented when the inter-vehicle distance L between vehicle 36 and the driver's own vehicle 8 is less than or equal to the second inter-vehicle distance Lth2, the relative speed is low, and the driver's own vehicle 8 and vehicle 36 are traveling essentially parallel.

[0026] It should be noted that the BSM / LCA unit 12 detects whether the relative position relationship between the vehicle 8 and the vehicle 36 positioned diagonally behind the vehicle 8 corresponds to relationship (a) or relationship (b), even if the BSM / LCA switch 35 is off. If the relative position relationship corresponds to relationship (a) or relationship (b), a license plate is switched to on.

[0027] One in the flowchart in Fig. The license plate setting program shown in section 6 is executed by the BSM / LCA units 12 in parallel to the BSM / LCA program. At S11, it is determined whether vehicle 36 is detected in the area Rm. If vehicle 36 is detected, the inter-vehicle distance L is obtained at S12. At S13, it is determined whether the inter-vehicle distance L is less than or equal to the second inter-vehicle distance Lth2. If S13 is positive (Yes), S14 determines whether the condition lasted longer than or equal to the set parallel driving time T0. If the condition lasted longer than or equal to the set parallel driving time T0, S14 is positive (Yes). At S15, the license plate is switched to "On".In this case, it is taken into account that the distance between vehicle 36 and the user's vehicle 8 is short, the relative speed is low, and vehicle 8 and vehicle 36 are essentially traveling parallel to each other. If, on the other hand, the state in which vehicle 36 is located in area R5 lasts no longer than or equal to the set parallel travel time T0, or if the distance between vehicles L is greater than the second distance between vehicles Lth2, the collision estimate time TTC is obtained at S16, and at S17 it is determined whether the collision estimate time TTC is shorter than or equal to the second estimate time Tth2. If a positive determination (Yes) is made at S17, the indicator at S15 is switched to On. If a negative determination (No) is made at S17, the indicator at S18 is switched to Off.

[0028] The LDA control is implemented according to the flowchart in Fig. The LDA program shown in section 3 is executed. The LDA program is executed at any time after a set duration has elapsed. At S21, it is determined whether the LDA switch 48 is on. If the LDA switch 48 is on, S22 determines whether the vehicle's speed V0 is higher than a set speed Vth. That is, the LDA control is executed if the vehicle's speed V0 is higher than the set speed Vth. If S22 is positive (yes), S23 determines the close-range distance D between the vehicle 8 and the lane boundary A based on the image captured by the front camera 40. At S24, it is determined whether the license plate is on. If the license plate is off, S25 sets a threshold Dth for the close-range distance D to the first close-range distance Dth1, which is less than or equal to the second close-range distance Dth2.S26 determines whether the direction indicator switch 16 is "On," that is, whether the direction indicator switch 16 has been activated by the driver. If the direction indicator switch 16 has not been activated and S26 returns a negative result (No), S27 determines whether the short-range distance D is less than or equal to the first short-range distance Dth1; in other words, it determines whether the deviation probability value is greater than or equal to the first threshold. If S27 returns a positive result (Yes), it is determined that the driver does not intend to change lanes and the deviation probability value is greater than or equal to the first threshold. S28 then controls the electric motor 18 to execute the lane departure warning system.

[0029] If the short distance D is greater than the first short distance Dth1, a negative determination (No) is made at S27 and processing at S28 is not executed. This is because the deviation probability value is smaller than the first threshold, and therefore there is little need to execute the lane departure prevention support. If the direction indicator switch 16 is On, a positive determination (Yes) is made at S26 and processing at S28 is not executed. This is because the driver intends to change lanes, and therefore there is no need to execute the lane departure prevention support.

[0030] If, in contrast, the indicator is on, a positive determination (Yes) is made at S24, and at S29 the threshold value Dth is determined as the second short distance Dth2, which is greater than the first short distance Dth1. In this case, at S27 it is determined whether the short distance D is less than or equal to the second short distance Dth2, without detecting the on / off state of the direction indicator switch 16. If the short distance D is less than or equal to the second short distance Dth2, it is determined that the deviation probability value is greater than or equal to the second threshold, and at S28 the lane deviation prevention support is executed.

[0031] In the present embodiment as described above, the LDA control is executed when the deviation probability value is greater than or equal to the second threshold, and when the relative position relationship between the vehicle 8 and the vehicle 36 corresponds to the set relationship, even if the deviation probability value is less than or equal to the first threshold. This configuration results in an increase in the opportunities for executing the LDA control, leading to improved safety. If the deviation probability value is less than the first threshold, the LDA control is executed at a later time, similar to the times at which the BSM and LCA controls are executed. This operation significantly reduces driver distraction.

[0032] In the present embodiment, the deviation probability value maintenance device 44, a maintenance device for a lateral deviation amount, and a close-range maintenance device are, for example, constructed by sections of the control device 42 of the LDA unit 10, which control the processing at S23 in the flowchart in Fig. 3. Store and execute. The support control device 46 is, for example, constructed by sections of the control device 42 of the LDA unit 10, which store and execute the processing at S24 to S29. A first support control device is, for example, constructed by sections of the support control device that store and execute the processing at S24 to S28. A second support control device is, for example, constructed by sections of the support control device that store and execute the processing at S24 and S27 to S29. The sections of the support control device that store and execute the processing at S28 also correspond to an example of an inter-vehicle distance-dependent support control device and an estimation time-dependent support control device.A threshold determination device corresponds to an example of sections of the support control device that store and execute the processing at S24, S25, and S29. A value (W / 2 - D1th) obtained by subtracting the first near distance from half the lane width W corresponds to an example of a first lateral deviation amount. A value (W / 2 - D2th) obtained by subtracting the second near distance from half the lane width W corresponds to an example of a second lateral deviation amount.

[0033] A maintenance device for a relative position relationship (the maintenance device 38 for a relative position relationship of the millimeter-wave radar 30) is, for example, constructed by sections of the BSM / LCA unit 12, which perform the processing at S3 and S8 according to the flowchart in Fig. 5 BSM / LCA program shown, and the processing at S12, S14 and S16 in the flowchart in Fig. The license plate setting program shown in Figure 6 is stored and executed. For example, an inter-vehicle distance maintenance device is constructed using sections of the maintenance device for a relative position relationship, which store and execute the processing at S3 and S12. Similarly, a collision estimation time maintenance device is constructed using sections of the maintenance device for a relative position relationship, which store and execute the processing at S8 and S16. An inter-vehicle distance-dependent display activation device and an estimation time-dependent display activation device (the LCD control device 39) are constructed using sections of the control device 32 of the BSM / LCA unit 12, which store and execute the processing at S5 to S7.

[0034] While the embodiment has been described above, it is evident that the disclosure is not limited to the details of the illustrated embodiment, but can be implemented with various changes and modifications that might occur to a person skilled in the art, without deviating from the fundamental concept and scope of protection of the disclosure. In the embodiment described above, for example, the license plate is switched to "On" when, in the license plate setting program S14, it is determined that the state in which the inter-vehicle distance L is less than or equal to the second inter-vehicle distance Lth2 has lasted longer than or equal to the set parallel driving time T0. However, the processing in S14 is not essential. The license plate can be switched to "On" if the inter-vehicle distance is less than or equal to the second inter-vehicle distance Lth2.

[0035] The LDA control is not limited to the control described above and can be implemented in various ways. For example, with LDA control, the wheels can be rotated or steered in a direction that prevents the vehicle from deviating from the lane, or a high probability of the vehicle deviating from the lane can be detected visually or audibly by the driver. The BSM control and the LCA control can likewise be implemented in various ways and are not limited to the illumination and flashing of the LCD light 34.A control action that is executed when the deviation probability value is greater than or equal to the first threshold, and a control action that is executed when the deviation probability value is greater than or equal to the second threshold, can be implemented in different ways. For example, the magnitude of an output provided by the electric motor 18 can differ between the case in which the deviation probability value is greater than or equal to the first threshold and the case in which the deviation probability value is greater than or equal to the second threshold. The method of actuation of the indicator or display device can also differ between these cases.Alternatively, the driving assistance device can be configured such that the electric motor 18 is controlled when the deviation probability value is greater than or equal to the first threshold, and the indicator, such as the LED light 34, can be activated when the deviation probability value is greater than or equal to the second threshold.

[0036] The lateral deviation amount can be obtained, for example, based on a vehicle speed and a yaw rate of the vehicle 8, and this can be obtained taking map information into account. While the control devices in the embodiment described above are provided individually for the BSM / LCA unit 12 and the LDA unit 10, a single control device can be used jointly by the BSM / LCA unit 12 and the LDA unit 10. Claimable inventions

[0037] Claimable inventions are described. (1) Driving assistance device comprising: a deviation probability value conservation device configured to obtain a deviation probability value representing a probability degree of a deviation of one's own vehicle from a lane; a maintenance device for a relative position relationship, which is configured to detect another vehicle located on the rear and lateral sides of the own vehicle, and maintains a relative position relationship between the other vehicle and the own vehicle; a support execution device configured to perform a track deviation prevention support; and a support control device configured to control the support execution device to execute the track deviation prevention support when the deviation probability value obtained by the deviation probability value maintenance device is greater than or equal to a threshold value, wherein the support control device includes a threshold determination device configured to determine the threshold as a smaller value when the relative position relationship maintained by the relative position relationship maintenance device corresponds to a set relationship, compared to when the relative position relationship does not correspond to the set relationship, and where the set relationship corresponds to a relationship in which, in the event of a deviation of one's own vehicle from the lane, there is a probability of a collision between one's own vehicle and the other vehicle. (2) The driving assistance device according to the above form (1), wherein the assistance control device comprises: a first support control device configured to determine the threshold as a first threshold when the relative position relationship does not match the set relationship, and to control the support execution device when the deviation probability value is greater than or equal to the first threshold; and a second support control device configured to determine the threshold as a second threshold that is smaller than the first threshold when the relative position relationship corresponds to the set relationship, and to control the support execution device when the deviation probability value is greater than or equal to the second threshold.

[0038] The support device can, for example, include a power steering device and / or an indicator configured to indicate a probability of the vehicle deviating from its lane. An example of the indicator is an alarm or warning device configured to generate an alarm. Examples of situations where the relative position does not match the set relationship include not only a situation where another vehicle is positioned diagonally behind the vehicle and the relative position between the other vehicle and the vehicle does not match the set relationship, but also a situation where no other vehicle is present.

[0039] (3) Driving assistance device of the above form (2), further comprising: an indicator; and a display activation device configured to activate the indicator when the relative position relationship matches a first set relationship, wherein the set relationship has a second set relationship, which corresponds to a relationship with a greater tendency for the distance between the own vehicle and the other vehicle to decrease than the first set relationship, and wherein the second support control device is configured to control the support execution device when the relative position relationship corresponds to the second set relationship and the deviation probability value is greater than or equal to the second threshold.

[0040] Examples of relationships with a greater tendency towards decreasing distance include: a relationship where the vehicle and the other vehicle are close together (i.e., the distance between the vehicles is short); and a relationship where the distance between the vehicle and the other vehicle decreases rapidly (i.e., the estimated collision time is short). Therefore, the second relationship can be set to a relative position relationship where the distance between the vehicles and / or the estimated collision time is / are smaller than that of the first relationship. The indicator is configured to indicate the presence of another vehicle whose relative position to the vehicle corresponds to the first relationship. (4) Driving assistance device in accordance with the above form (2) or (3), wherein the maintenance device for a relative position relationship includes an inter-vehicle distance maintenance device which is configured such that it maintains an inter-vehicle distance between the other vehicle and its own vehicle as the relative position relationship, the driving assistance device includes: an indicator; and an inter-vehicle distance-dependent display activation means configured to activate the indicator when the inter-vehicle distance maintained by the inter-vehicle distance maintenance device is less than or equal to a first inter-vehicle distance, and wherein the second support control device includes an inter-vehicle distance-dependent support control device configured to determine that the relative position relationship corresponds to the set relationship and controls the support execution device when the deviation probability value is greater than or equal to the second threshold, and when the inter-vehicle distance is less than or equal to a second inter-vehicle distance that is less than the first inter-vehicle distance.

[0041] In cases where the deviation probability value is lower than the first threshold, when the lane departure prevention assistance is activated when the inter-vehicle distance between the vehicle and the other vehicle becomes less than or equal to the first inter-vehicle distance, some drivers find it distracting. To address this issue, the lane departure prevention assistance is activated when the inter-vehicle distance becomes less than or equal to the second inter-vehicle distance, thus reducing driver distraction. The indicator may or may not be the same device as the assistance activation device. For example, the power steering device can be controlled to indicate that the inter-vehicle distance between the vehicle and the other vehicle is less than or equal to the first inter-vehicle distance.It should be noted that, in the case of the driving assistance device of this type, the relationship in which the inter-vehicle distance is less than or equal to the first inter-vehicle distance corresponds to the first set relationship, and the relationship in which the inter-vehicle distance is less than or equal to the second inter-vehicle distance corresponds to the second set relationship.

[0042] (5) Driving assistance device according to the preceding form (4), wherein the inter-vehicle distance-dependent assistance control device is configured to determine that the relative position relationship corresponds to the set relationship and controls the assistance execution device when a condition in which the inter-vehicle distance is less than or equal to the second inter-vehicle distance has lasted for a time longer than or equal to a set parallel driving time.

[0043] In this configuration, the lane departure prevention support is executed in cases where the vehicle and the other vehicle are essentially driving parallel to each other, further reducing disturbance or annoyance to the driver.

[0044] (6) Driving assistance device according to one of the above forms (2) to (5), wherein the maintenance device for a relative position relationship includes a collision estimation time maintenance device which is configured such that it maintains a collision estimation time between the other vehicle and its own vehicle as the relative position relationship, the driving assistance device includes: an indicator; and an estimation-time-dependent display activation means configured to activate the indicator when the collision estimation time obtained by the collision estimation time maintenance device is less than or equal to a first estimation time, and wherein the second support control device includes an estimation time-dependent support control device which is configured to determine that the relative position relationship corresponds to the set relationship and controls the support execution device when the deviation probability value is greater than or equal to the second threshold, and when the collision estimation time is less than or equal to a second estimation time which is less than the first estimation time.

[0045] With this driver assistance device, lane departure prevention support is executed when the deviation probability value is greater than or equal to the second threshold and the collision estimation time is less than, or shorter than, or equal to the second estimation time. This configuration can reduce driver disturbance or annoyance compared to a case where lane departure prevention support is executed when the collision estimation time is less than or equal to the first estimation time. With this driver assistance device, the relationship where the collision estimation time is less than or equal to the first estimation time corresponds to the first set relationship, and the relationship where the collision estimation time is less than, or shorter than, or equal to the second estimation time corresponds to the second set relationship.The inter-vehicle distance-dependent indicator activation means and the estimation time-dependent indicator activation means may or may not be implemented using the same device. In other words, the indicator may be activated in the same way or in different ways depending on whether the inter-vehicle distance is less than or equal to the first inter-vehicle distance or the collision estimation time is less than or equal to the first estimation time.

[0046] (7) Driving assistance device according to one of the above forms (2) to (6), wherein the deviation probability value conservation device includes a conservation device for a lateral deviation amount which is configured to receive a lateral deviation amount corresponding to a deviation amount of the vehicle's own vehicle in a transverse direction, wherein the first support control device is configured to determine that the deviation probability value is greater than or equal to the first threshold, and controls the support execution device when the lateral deviation amount obtained by the lateral deviation maintenance device is greater than or equal to a first lateral deviation amount, and wherein the second support control device is configured to determine that the deviation probability value is greater than or equal to the second threshold when the lateral deviation amount is greater than or equal to a second lateral deviation amount that is less than the first lateral deviation amount, and controls the support execution device when the relative position relationship corresponds to the set relationship.

[0047] (8) Driving assistance device according to the preceding form (7), wherein the lateral deviation maintenance device comprises a close-range maintenance device configured to obtain a close-range distance based on an image taken by an image-capturing device provided at a front section of the own vehicle, wherein the close-range distance corresponds to a distance between a lane boundary and the own vehicle.

[0048] (9) Driving assistance device according to one of the above forms (2) to (8), wherein the vehicle itself has an intent change estimation device configured to estimate whether a driver intends to change lanes, wherein the first support control device is configured to control the support execution device when the intention change estimator has estimated that the driver does not intend to change lanes, and when the deviation probability value is greater than or equal to the first threshold, and wherein the second support control device is configured such that it controls the support execution device regardless of whether the driver intends to change lanes, if the deviation probability value is greater than or equal to the second threshold and if the relative position relationship corresponds to the set relationship.

[0049] Whether or not the driver intends to change lanes can be estimated based on the on / off state of a turn signal switch and / or the amount of force applied to a steering control element. If the driver is estimated to intend a lane change, it is preferable to make the lane departure prevention assistance more difficult to execute, even if the probability of deviation is high.In contrast, if the relative positional relationship between one's own vehicle and the other vehicle corresponds to the set relationship, for example, if there is a high probability of a collision between one's own vehicle and another vehicle positioned diagonally behind it in the event of one's own vehicle deviating from the lane, it is preferable to execute the lane departure prevention support regardless of whether or not there is an intention to change lanes.Examples of the wording “the second assistance control device is configured to control the assistance execution device regardless of whether the driver intends to change lanes” include: a configuration in which the second assistance control device controls the assistance execution device without estimating the change of intent estimator; and a configuration in which the second assistance control device is configured to control the assistance execution device regardless of an estimation result of the change of intent estimator.

Claims

[1] Driving assistance device comprising: a deviation probability value maintenance device (44) which is configured such that it receives a deviation probability value which represents a probability degree of a deviation of one's own vehicle (8) from a lane; a maintenance device (38) for a relative position relationship, which is configured such that it detects another vehicle (36) which is positioned diagonally behind the own vehicle (8), and maintains a relative position relationship between the other vehicle (36) and the own vehicle (8); a support execution device (20) configured to perform a track deviation prevention support; and a support control device (46) configured to control the support execution device (20) to execute the track deviation prevention support when the deviation probability value obtained by the deviation probability value maintenance device (44) is greater than or equal to a threshold value, wherein the support control device (46) has a threshold determination device (46) which is configured such that it determines the threshold as a smaller value when the relative position relationship maintained by the maintenance device (38) for a relative position relationship corresponds to a set relationship, compared to when the relative position relationship does not correspond to the set relationship, wherein the set relationship corresponds to a relationship in which, in the event of a deviation of the own vehicle (8) from the lane, there is a probability of collision of the own vehicle (8) with the other vehicle (36), the support control device (46) further comprises: a first support control device (46) configured to determine the threshold as a first threshold when the relative position relationship does not correspond to the set relationship, and to control the support execution device (20) when the deviation probability value is greater than or equal to the first threshold; and a second support control device (46) configured to determine the threshold as a second threshold that is smaller than the first threshold when the relative position relationship corresponds to the set relationship, and to control the support execution device (20) when the deviation probability value is greater than or equal to the second threshold, wherein the maintenance device (38) for a relative position relationship has an inter-vehicle distance maintenance device (38) which is configured such that it maintains an inter-vehicle distance (L) as the relative position relationship, the driving assistance device includes: an indicator (20, 34); and an inter-vehicle distance-dependent display activation means (39, 46) which is configured such that it activates the indicator (20, 34) when the inter-vehicle distance (L) maintained by the inter-vehicle distance maintenance device (38) is less than or equal to a first inter-vehicle distance (Lth1), wherein the second support control device (46) has an inter-vehicle distance-dependent support control device (46) which is configured to determine that the relative position relationship corresponds to the set relationship and controls the support execution device (20) when the deviation probability value is greater than or equal to the second threshold value and when the inter-vehicle distance (L) is less than or equal to a second inter-vehicle distance (Lth2) which is less than the first inter-vehicle distance (Lth1), and wherein the inter-vehicle distance-dependent support control device (46) is configured such that it determines that the relative position relationship corresponds to the set relationship and controls the support execution device (20) when a condition in which the inter-vehicle distance (L) is less than or equal to the second inter-vehicle distance (Lth2) has lasted for a time longer than or equal to a set parallel travel time (T0). [2] Driving assistance device according to claim 1, wherein the maintenance device (38) for a relative position relationship includes a collision estimation time maintenance device (12) which is configured such that it receives a collision estimation time (TTC) as the relative position relationship, the driving assistance device includes: an indicator (20, 34); and an estimation-time-dependent display activation means (39) configured to activate the indicator (20, 34) when the collision estimation time (TTC) obtained by the collision estimation time maintenance device (12) is less than or equal to a first estimation time (Tth1), and wherein the second support control device (46) has an estimation time-dependent support control device which is configured to determine that the relative position relationship corresponds to the set relationship and controls the support execution device (20) when the deviation probability value is greater than or equal to the second threshold and when the collision estimation time (TTC) is less than or equal to a second estimation time (Tth2) which is less than the first estimation time (Tth1). [3] Driving assistance device according to claim 1 or 2, wherein the deviation probability value conservation device (44) has a conservation device (42) for a lateral deviation amount which is configured such that it receives a lateral deviation amount (Δw) corresponding to a deviation amount of its own vehicle (8) from a center line (C) of the lane in a transverse direction, wherein the first support control device (46) is configured to determine that the deviation probability value is greater than or equal to the first threshold value, and controls the support execution device (20) when the lateral deviation amount (Δw) obtained by the maintenance device (42) for a lateral deviation amount is greater than or equal to a first lateral deviation amount (W / 2 - D1th), and wherein the second support control device (46) is configured to determine that the deviation probability value is greater than or equal to the second threshold value when the lateral deviation amount (Δw) is greater than or equal to a second lateral deviation amount (W / 2 - D2th) that is less than the first lateral deviation amount (W / 2 - D1th), and controls the support execution device (20) when the relative position relationship corresponds to the set relationship. [4] Driving assistance device according to one of claims 1 to 3, wherein the deviation probability value maintenance device (44) has a close-distance maintenance device (42) which is configured to maintain a close distance (D) which corresponds to a distance between a reference point (Pv) of the vehicle (8) and a lane boundary (A), wherein the first support control device (46) is configured to determine that the deviation probability value is greater than or equal to the first threshold, and controls the support execution device (20) when the close distance (D) maintained by the close distance maintenance device (42) is less than or equal to a first close distance (Dth1), and wherein the second support control device (46) is configured to determine that the deviation probability value is greater than or equal to the second threshold when the close distance (D) is less than or equal to a second close distance (Dth2) that is greater than the first close distance (Dth1), and controls the support execution device (20) when the relative position relationship corresponds to the set relationship.

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