DRIVING ASSISTANCE DEVICE

Abstract

Driving assistance device (22, 26, 10, 14, 40) designed to carry out driving assistance in such a way that a host vehicle (8) travels within a lane, the driving assistance device (22, 26, 10, 14, 40) comprising: an object information acquisition device (40) configured to acquire object information relating to at least one object in an area; an environment detection device (42) designed to detect a relative positional relationship between the host vehicle (8) and the object located in the area and identified on the basis of the object information detected by the object information detection device (42); and an assistance inhibiting device (10, 26, 17) configured to inhibit the driving assistance when an absolute value of a steering operation value representing an amount of steering operation performed by a driver is greater than an inhibition threshold value (Tsth); wherein the assistance inhibition device (10, 26, 17) comprises a threshold value determination device (10, 17) which is designed, when the relative positional relationship between the object and the host vehicle (8) detected by the environment detection device (42) is a specific relationship in which it is anticipated that the driver will perform a steering operation in a direction in which the host vehicle (8) avoids the object, to determine a smaller value as the inhibition threshold value (Tsth) than if the relative positional relationship between the object and the host vehicle (8) detected by the environment detection device (42) were not the specific relationship, wherein the threshold value determination device (10, 17) comprises: an external disturbance detection device (10, 26) designed to detect the intensity of an external disturbance acting on the host vehicle (8); and an external disturbance-dependent threshold value determining device (10, 17) which is designed to determine a larger value as the inhibition threshold value (Tsth) when the strength of the external disturbance detected by the external disturbance detection device (10, 26) is large than when the strength of the external disturbance detected by the external disturbance detection device (10, 26) is small, wherein the threshold value determination device (10, 17) dependent on an external disturbance is designed to determine a larger value as the inhibition threshold value (Tsth) when the strength of the external disturbance detected by the device (10, 26) for detecting an external disturbance is greater than a set value for the external disturbance than when the strength of the external disturbance detected by the device (10, 26) for detecting an external disturbance is less than or equal to the set value for the external disturbance, wherein the threshold value determination device (10, 17) comprises a threshold value determination device (10, 17) dependent on an object that has come into range, which is designed to determine a smaller value as the inhibition threshold value (Tsth) when a time that the own vehicle (8) is expected to need to collide with an object that has come into range, which is an object that is first detected by the environment detection device (42), is short than if the time that the own vehicle (8) is expected to need to collide with the object that has come into range would be long, and wherein the threshold value determination device (10, 17) dependent on an object that has come into range is designed, when the strength of the external interference detected by the device (10, 26) for detecting an external interference is less than or equal to the set value for the external interference, to determine a smaller value as the inhibition threshold value (Tsth) when the time that the host vehicle (8) is expected to need to collide with the object that has come into range is short than when the time that the host vehicle (8) is expected to need to collide with the object that has come into range is long.

Description

BACKGROUND

[0001] The invention relates to a driving assistance device designed to assist a driver while driving.

[0002] Japanese patent application JP 2010-271999 A discloses a driving assistance device designed to assist driving to prevent a vehicle from deviating from a lane. In the driving assistance device disclosed in JP 2010-271999 A, an electric steering device is controlled to apply a steering torque if there is a likelihood of a vehicle deviating from a lane. This operation prompts a driver to perform steering to prevent the vehicle from deviating from the lane.DE 10 2009 044 269 A1 discloses a steering assist device that can be used in a vehicle, such as a passenger car, and is configured to detect the environment in front of the vehicle and apply steering force to a steering mechanism of the vehicle to reduce interference with the driver's steering operation when avoiding a neighboring vehicle. DE 10 2014 225 752 A1 further discloses a lane departure warning system with a lane departure warning unit that suppresses or restricts a lane departure warning operation performed by a vehicle when at least one of restriction determinations is performed by a lane state determination unit. With regard to the prior art, reference is also made to JP 2006 - 331 304 A, JP 2005 - 343 305 A, WO 2015 / 012 090 A1 and JP 2009-208505 A. SUMMARY

[0003] Accordingly, the object of the invention is to achieve an improvement in a driving assistance device, for example, to reduce the driver's sense that something unusual is occurring. This object is achieved by the driving assistance device having the features of claim 1; advantageous further developments are the subject of the subclaims.

[0004] A driving assistance device according to the present aspect is configured to perform driving assistance such that a subject vehicle travels within a lane. In the present driving assistance device, driving assistance is inhibited when an absolute value of a steering operation amount is greater than an inhibition threshold. However, a small value is set as the inhibition threshold when a relative positional relationship between an object and a subject vehicle is one for which a steering operation is expected to be performed in a direction in which the subject vehicle avoids the object.Examples of steering in the direction in which the own vehicle avoids the object include: a steering operation in a direction in which the own vehicle moves away from the object, in the case where the object is laterally in front of the own vehicle; and a steering operation in a direction in which the own vehicle moves to the right or to the left to avoid the object, in the case where the object is in front of the own vehicle. The object that is laterally in front of the own vehicle or in front of the own vehicle can be considered to have a relative positional relationship with the own vehicle for which the steering operation is expected to be performed in the direction in which the own vehicle avoids the object.

[0005] For example, in the case where the object is laterally offset in front of the host vehicle or in front of the host vehicle and the driver has performed the steering operation in the direction in which the host vehicle is avoiding the object, when a steering torque is applied by the drive assistance, which is performed to keep the host vehicle traveling within the lane, a direction of the steering torque is opposite to the direction of the steering operation performed by the driver. Thus, the driver feels that something abnormal is happening. In the present drive assistance device, on the other hand, the inhibition threshold is lowered in the case where the above-described object is present. That is, the drive assistance is inhibited even when the absolute value of the steering operation value is small, thereby making it difficult or even impossible to perform the drive assistance.As a result, the driver will not easily feel that something unusual is going on. SHORT DESCRIPTION OF THE DRAWINGS:

[0006] The objects, features and advantages and the technical and industrial significance of the present invention will be better understood by reading the following detailed description of the embodiments when considered in conjunction with the accompanying drawings: Fig. 1 is a view illustrating a relative positional relationship between an object and a host vehicle having a driving support device according to a first embodiment; Fig. 2 is a block diagram illustrating the principle of the driving support device; Fig. 3 is a flowchart illustrating a flow of a cancel flag setting program stored in a memory of a driving support ECU of the own vehicle; Fig. 4A is a flowchart illustrating a flow of a threshold determination program stored in the memory; Fig. 4B is a flowchart showing a flow of a portion of the threshold determination program (a determination of whether or not an evasive steering operation is being performed); Fig. 5 is a flowchart illustrating a flow of a lane departure warning (LDA) control program stored in memory; Fig. 6 is a view illustrating a lateral distance of the own vehicle; Fig. 7 is a flowchart showing a flow of a program stored in memory for detecting an unevenness of a road surface; Fig. 8A is a view illustrating changes in a steering torque in the own vehicle in the case where an unevenness of a road surface is small; Fig. 8B is a view illustrating changes in a steering torque in the own vehicle in the case where the unevenness of the road surface is large; Fig. 8C is a view for explaining the detection of road surface unevenness; Fig. 9 is a view showing a relative positional relationship between an own vehicle and a specific object in the case where a driver feels that something abnormal is happening; Fig. 10 is a view showing another relative positional relationship between the own vehicle and the specific object in the case where a driver feels that something abnormal is happening; Fig. 11 is a flowchart illustrating a flow of another threshold value determination program stored in the memory; Fig. 12 is a flowchart illustrating a flow of still another threshold value determination program stored in memory; Fig. 13 is a flowchart illustrating a flow of still another threshold value determination program stored in memory; Fig. 14 is a flowchart illustrating a flow of still another threshold value determination program stored in memory; Fig. 15 is a flowchart illustrating a flow of a threshold value determination program stored in memory in a driving support device according to a second embodiment; and Fig. 16 is a flowchart illustrating a flow of a threshold value determination program stored in a memory in a driving support device according to a third embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0007] Embodiments are described below with reference to the drawings. First embodiment

[0008] A driving support device according to the present embodiment is installed in a dedicated vehicle 8, which is in Fig. 1. As shown in Fig. 2, the host vehicle 8 includes an electric drive support control unit (ECU) 10, a steering ECU 12, an annunciator 14, a vehicle speed sensor 15, a direction indicator switch 16, an occupancy detector 17, and a warning lamp switch 18. These devices are communicatively connected to each other via a Controller Area Network (CAN) 19. The vehicle speed sensor 15 detects a vehicle speed Vs based on wheel speeds of left and right front wheels and left and right rear wheels of the host vehicle 8. The vehicle speed Vs is a traveling speed of the host vehicle 8. The direction indicator switch 16 is operable by the driver and indicates a traveling direction of the host vehicle 8 (corresponding to a direction of a steering operation) when the steering operation is performed.

[0009] The occupancy detector 17 includes an occupancy sensor 17a and a plurality of occupancy sensors 17b, each provided to correspond to a seat in the host vehicle. The occupancy sensor 17a is provided for a driver's seat 17x, and the occupancy sensors 17b are each provided on a plurality of passenger seats 17y different from the driver's seat 17x. Both the occupancy sensor 17a and the occupancy sensors 17b detect whether, for example, a person is occupying a corresponding seat. The warning lamp switch 18 is turned on to illuminate a warning lamp (not shown). For example, the warning lamp switch 18 is turned on when the host vehicle 8 is parked and departs from the lane.

[0010] The steering ECU 12 is an element of a steering system 20 and mainly consists of a computer including an executor, a memory, and an input / output device. The steering system 20 includes: an electric steering assist device 22 including an electric motor 21; a steering wheel 24 as a steering operating element; a steering torque sensor 26; and an operating angle sensor 28. The electric motor 21, the steering torque sensor 26, and the operating angle sensor 28 are connected, for example, to the input / output device of the steering ECU 12.

[0011] The electric steering assist device 22 is configured to turn steered road wheels using (i) a steering torque applied by a driver to a steering mechanism via the steering wheel 24 and (ii) a steering torque applied by the electric motor 21 to the steering mechanism. The steering ECU 12 controls the electric motor 21 to regulate the steering torque applied to the steering mechanism. Examples of applying the steering torque to the steering mechanism include: applying the steering torque to the steering mechanism in the same direction in which a driver performs a steering operation; applying the steering torque to the steering mechanism in a direction opposite to the direction of the steering operation performed by the driver; and applying the steering torque to the steering mechanism without the driver's steering operation.

[0012] The steering torque sensor 26 is configured to detect a steering torque applied by the driver via the steering wheel 24 to a torsion bar of the steering mechanism. The steering torque sensor 26 outputs a steering torque applied by turning the steering wheel 24 in a rightward direction as a positive value and outputs a steering torque applied by turning the steering wheel 24 in a leftward direction as a negative value. In the present embodiment, a steering direction flag Fs is set to right (Fs=2) when the steering torque is applied in the rightward direction, and when the steering torque is applied in the leftward direction, the steering direction flag Fs is set to left (Fs=1). When no steering torque is applied in the rightward direction or in the leftward direction, the steering direction flag Fs is set to "0."

[0013] The operating angle sensor 28 is designed to detect the angle through which the steering wheel 24 is rotated from a reference position. The reference position of the steering wheel 24 is a position of the steering wheel 24 when the host vehicle 8 is traveling straight ahead without external interference.

[0014] The notification device 14 may, for example, issue a visual notification using a display, light, or the like, and may issue an audible notification using a loudspeaker or the like.

[0015] The driving support ECU 10 mainly consists of a computer including an executor, a memory, and an input / output device, which are not shown. A camera 40 configured to capture an image, a lane departure warning (LDA) switch 41, and the like are connected to the input / output device of the driving support ECU 10. The camera 40 is installed on a rear surface of a windshield of the host vehicle 8 and is capable of capturing images within a region Rf defined in Fig. 1 and located in front of and laterally offset from the host vehicle 8, to capture an image including an object and lane lines. The LDA switch 41 is driver-operable and is switched on when the driver permits the execution of the LDA control as driving assistance.

[0016] The driving support ECU 10 includes an environment detection device 42, an LDA control device 46, and an LDA control inhibiting device 48.

[0017] The surroundings detection device 42 is configured to detect an environment in an area based on the image captured by the camera 40, and includes a lane detection device 50 and a relative positional relationship detection device 52. The area in which the environment is detected by the surroundings detection device 42 is determined according to, for example, a location where the camera is installed and the characteristics of the camera. In the present embodiment, the camera 40 is installed in a front portion of the host vehicle, and therefore, the region Rf is an area located in front of and laterally offset from the host vehicle. The surroundings are determined by a relative positional relationship between the host vehicle and the object located in the region Rf.In some cases, a relative positional relationship between the object and the lane lines defining one's own lane can be considered a relative positional relationship between the object and one's own vehicle.

[0018] The lane line detection device 50 is designed to detect lane lines in the region Rf based on the image captured by the camera 40. As shown in Fig. 1, for example, in the case where the host vehicle 8 is traveling on its own lane S, the lane line recognition device 50 identifies lane lines A, B that delimit the host lane S from opposite sides. The relative positional relationship detection device 52 is designed to identify an object X based on the image captured by the camera 40 and to detect the relative positional relationship between the object X and the host vehicle 8. As the relative positional relationship between the host vehicle 8 and the object X, the relative positional relationship detection device 52 in the present embodiment detects, as shown in Fig. 1: a vehicle-to-object distance L, that is, a distance between the own vehicle 8 and the object X in a front-to-rear direction, which may be referred to as a “travel direction”; an object lateral distance dv, that is, a distance between a predetermined reference point Pv on the object X and the lane line A that borders the own lane S and is closer to the object X than the lane B, in a lateral direction of the own vehicle 8, which may be referred to as a “width direction”; a relative speed; and a direction that runs from the own vehicle 8 to the object X.

[0019] The vehicle-object distance L is a value that is recorded under the assumption that the own vehicle 8 and the object X are in the same lane. As in Fig. 1, the object lateral distance dv takes a positive value when the predetermined reference point Pv on the object X lies outside the own lane S, that is, when the predetermined reference point Pv lies, for example, on a side of the lane line A opposite to the own lane S. The object lateral distance dv takes a negative value when the predetermined reference point Pv lies in the own lane S, that is, when the predetermined reference point Pv and the own lane S are on the same side of the lane line A. When the object lateral distance dv is small, the distance between the object X and the own vehicle 8 in the lateral direction becomes relatively smaller than if the object lateral distance dv were large. Thus, the object lateral distance dv can be regarded as a physical quantity representing a relative positional relationship between the own vehicle 8 and the object X in the lateral direction.The direction from the own vehicle 8 to the object X is, for example, in the case shown in . Fig. 1 is shown, a direction to the front right.

[0020] In the present embodiment, in the case where the vehicle-object distance L is less than or equal to a set vehicle-object distance Lth and the object side distance dv is less than or equal to a first set object side distance dvth1 (a positive value), and an approach speed SV as a relative speed is higher than or equal to a set approach speed SVth, it is determined that the object X and the host vehicle 8 have a predetermined specific relationship, and the object X is set as the specific object OV. In the case where the specific object OV is present, it is expected that the driver must perform a steering operation in a direction in which the host vehicle 8 avoids the specific object OV, and it is expected that the host vehicle 8 must avoid the specific object OV.In other words, the specific relationship may be a relationship for which the steering operation is expected to be performed in the direction in which the own vehicle 8 avoids the specific object OV.

[0021] When the object side distance dv is short, the driver may feel more strongly that the host vehicle 8 needs to avoid the object X than when the object side distance dv is long. The first set object side distance dvth1 can be set to a distance at which the driver is expected to perform the steering operation in the direction in which the host vehicle 8 avoids the object X. It is known that the first set object side distance dvth1 is generally 30 cm.

[0022] When the vehicle-to-object distance is short and the approach speed is high, it can be considered that there is a greater need for the driver to perform the steering operation in the direction in which the host vehicle 8 avoids the specific object OV than when the vehicle-to-object distance is long and the approach speed is low. Thus, for example, both the set vehicle-to-object distance Lth and the set approach speed SVth can be set to a value at which it can be considered that there is a strong need for the driver to perform the steering operation in the direction in which the host vehicle 8 avoids the specific object OV. For example, it is known that the set vehicle-to-object distance Lth and the set approach speed SVth are generally about 50 m and about 30 km / h, respectively.

[0023] When the object side distance dv is greater than or equal to a second set object side distance dvth2 (a negative value), it is determined that the object X is present on a front right side or a front left side of the own vehicle 8. The case where the object side distance dv is less than or equal to the first set object side distance dvth1 includes a case where at least a portion of the object X is located in the own lane.However, for example, in the case where more than half of the object X is located in the own lane, determination as to whether the object X is located on a front right side of the own vehicle 8 and whether the object is located on a front left side of the own vehicle 8 may be difficult, and determination as to whether the steering operation for avoiding the object X should be performed in the right direction or the left direction may be difficult.To solve this problem, in the present embodiment, when the object side distance dv is greater than or equal to the second set object side distance dvth2, it is determined that the object X is present on a front right side or a front left side of the own vehicle 8, and when the object side distance dv is smaller than the second set object side distance dvth2, it is determined that the object X is located in front of the own vehicle 8. Note that the second set object side distance dvth2 is generally -50 cm.

[0024] In the present embodiment, a time tc until an expected encounter is detected for the specific object OV first detected by the surroundings detection device 42. The time tc until the expected encounter is a period of time within which the host vehicle 8 is expected to encounter the specific object OV. The time tc until the expected encounter can be calculated based on the relative speed and the inter-vehicle distance between the host vehicle 8 and the object X. The specific object OV, as the object X that is first detected, may hereinafter be referred to as an "in-range object."The specific object OV as the object that has come into range may have come into range in front of the own vehicle 8 on the own lane S and may have come into range in front right or front left of the own vehicle 8, but in any case the time until the expected encounter is calculated under the assumption that the object OV that has come into range and the own vehicle 8 are in the same lane.

[0025] The LDA control device 46 is designed to carry out the LDA control for driving assistance in such a way that a deviation of the host vehicle 8 from the lane is prevented. If, as in Fig. 6, in a situation where a cancel flag, which will be described below, is OFF and execution of the LDA control is permitted, a lateral distance Ds of the own vehicle, which is one of a distance between a predetermined reference point Pa on the own vehicle 8 and the lane line A delimiting the own lane S and a distance between the reference point Pa and the lane line B delimiting the own lane S, which is shorter, is smaller than an initial threshold value Dsa, it is determined that the possibility of the own vehicle 8 departing is high, and the LDA control is started. In the LDA control, a steering torque Y is applied in a direction in which the lateral distance Ds of the own vehicle becomes larger. When the lateral distance Ds of the own vehicle is small, the amount of applied steering torque is larger than when the lateral distance Ds of the own vehicle were large.When the lateral distance Ds of the own vehicle exceeds a final threshold Dsb that is greater than the initial threshold Dsa, it is determined that the probability of departure of the own vehicle 8 has become low, and LDA control is terminated. The lateral distance Ds of the own vehicle is an example of a value representing the probability of departure, and when the lateral distance Ds of the own vehicle is short, it is determined that the probability of departure is higher than when the lateral distance Ds of the own vehicle were long.

[0026] LDA control is performed by executing the LDA control program. Fig. 5 is a flowchart illustrating a flow of the LDA control program. The LDA control program is executed in a cycle of predetermined time. This flow begins with S1, where the lateral distance Ds of the own vehicle and other values ​​are read. At S2, it is determined whether LDA control is currently being executed. If LDA control is not currently being executed, it is determined at S3 whether the cancel flag is ON. If the cancel flag is OFF, it is determined at S4 whether the lateral distance Ds of the own vehicle is smaller than the initial threshold Dsa. If the lateral distance Ds of the own vehicle is smaller than the initial threshold Dsa and the probability of departure is high, the steering ECU 12 issues a command to start LDA control at S5.The steering ECU 12 controls the electric motor 21 to assist driving by applying a steering torque in a direction that reduces the lateral distance Ds of the host vehicle. When the cancel flag is ON, an affirmative decision (YES) is made at S3, and the processing of S4 and S5 is not executed. The start of LDA control is inhibited regardless of the value of the lateral distance Ds of the host vehicle.

[0027] If the LDA control is currently being executed, an affirmative decision (YES) is made at S2, and it is determined at S6 whether the cancel flag is ON. If the cancel flag is OFF, it is determined at S7 whether the lateral distance Ds of the own vehicle is greater than the final threshold Dsb. If the lateral distance Ds of the own vehicle is less than or equal to the final threshold Dsb, it is assumed that there is a possibility of departure. Thus, a negative determination (NO) is made at S7, and the processings at S1, S2, S6, and S7 are repeated so that the LDA control continues. If the lateral distance Ds of the own vehicle becomes greater than the final threshold Dsb, the steering ECU 12 outputs a command to stop the LDA control at S8. The steering ECU 12 controls the electric motor 21 to end the LDA control. If the abort flag is ON, an affirmative decision (YES) is made at S6.In this case, the command to stop the electric motor 21 is issued at S8 without executing the processing at S7. Even if the lateral distance Ds of the host vehicle is less than or equal to the end threshold Dsb, the LDA control is terminated.

[0028] When an inhibition condition is met, for example, when an absolute value of the steering torque Ts is greater than an inhibition threshold Tsth, the LDA control inhibiting means 48 sets the cancel flag to ON to prevent the LDA control means 46 from executing the LDA control. The inhibition threshold Tsth is determined by a threshold determining means 54. For example, it is determined that the inhibition condition is met and the cancel flag is set to ON when at least one of the following cases applies: a case where the absolute value of the steering torque Ts detected by the steering torque sensor 26 is greater than the inhibition threshold Tsth; a case where the direction indicator switch 16 is ON; and a case where the warning lamp switch 18 is ON. If the abort flag is ON, the LDA control is not started and the LDA control that is currently executing is terminated.

[0029] When the absolute value of the steering torque Ts is greater than the inhibition threshold Tsth, it is expected that the driver intends to deviate from the own lane S by changing the lane or by moving the own vehicle 8 to one side for parking, for example. Thus, when the absolute value of the steering torque Ts is greater than the inhibition threshold Tsth, execution of the LDA control is not advisable, and the cancel flag is set to ON. The same operations are performed for the cases of the direction indicator switch 16 and the hazard lamp switch 18. Furthermore, it is also expected that the absolute value of the steering torque Ts becomes greater than the inhibition threshold Tsth when the steering operation is performed in the direction in which the own vehicle 8 avoids the specific object OV.

[0030] The abort flag is determined by executing an abort flag setting program. Fig. Figure 3 is a flowchart illustrating a flow of the cancel flag setting program. The flow starts with S21, where it is determined whether the cancel flag is ON. If the cancel flag is OFF, the steering torque Ts is read at S22. The inhibition threshold Tsth is read at S23. At S24, it is determined whether the absolute value of the steering torque Ts is greater than the inhibition threshold Tsth. At S25, it is determined whether the direction indicator switch 16 is ON. At S26, it is determined whether the warning lamp switch 18 is ON. If an affirmative decision (YES) is made in at least one of S24-S26, the cancel flag is set to ON at S27. That is, the LDA control is inhibited. If a negative decision (NO) is made in S24-26, the cancel flag is set to OFF at S28. That is, a start of the LDA control is allowed, and a continuation of the currently executing LDA control is allowed.

[0031] When the cancel flag is ON, it is determined at S29 whether a set period of time has elapsed. Before the set period of time elapses, the processing at S21 and S29 is repeated, and the cancel flag is kept ON. When the set period of time has elapsed, an affirmative decision (YES) is made at S29, and the cancel flag is turned OFF at S28. Thus, the cancel flag is turned ON and then OFF in the set period of time. The reason for this is that it is not advisable if a situation where the cancel flag is ON, that is, a situation where LDA control is inhibited, continues for a long time.

[0032] The threshold determination device 54 is configured to determine the inhibition threshold Tsth. The inhibition threshold Tsth is determined, for example, based on environmental information and an uneven road surface as an external disturbance. The environmental information is acquired by the environmental detection device 42 and indicates the relative positional relationship between the object X and the host vehicle 8. Examples of the environmental information include the vehicle-to-object distance, the object-side distance, the approach speed, the direction leading from the host vehicle 8 to the object X, the presence or absence of the object that has come within range, and the time until the expected encounter that the host vehicle 8 requires to encounter the object that has come within range.

[0033] When the object X having the specific relationship with the host vehicle 8 as the relative positional relationship, that is, the specific object OV, is present, a smaller value is set as the inhibition threshold value Tsth than when no specific object OV is present. When the specific object OV is not present, in the present embodiment, the inhibition threshold value Tsth is set to a value A. The value A may be a value that clearly indicates whether the driver intends to operate the host vehicle 8 to deviate from the lane, for example, whether the driver intends to change lanes or to move the host vehicle 8 out of the lane for parking. In this case, the LDA control is less likely to be inhibited and more likely to be executed.

[0034] If the specific object OV is present on a front right side of the own vehicle 8, such as in Fig. As shown in Figure 9, the driver performs the steering operation in the left direction to move the host vehicle 8 away from the object X along a path VL. If LDA control is executed in this situation, a rightward steering torque (indicated by an arrow YR) is applied to the steering mechanism. Since the direction of the steering operation performed by the driver (i.e., the left direction) and the direction of the applied steering torque are opposite to each other, the driver feels that something abnormal is happening.

[0035] Likewise, the driver performs the steering operation to the right to move the own vehicle 8 away from the object X along a path VR when the specific object OV is present on a front left side of the own vehicle 8, as shown in Fig. 10. If the LDA control is executed in this situation, a steering torque in the left direction (indicated by an arrow YL) is applied to the steering mechanism, which makes the driver feel that something abnormal is happening.

[0036] To solve this problem, in the present embodiment, in the case where the specific object OV is present, the inhibition threshold value Tsth is set to a value smaller than the value A. Thus, even if the absolute value of the steering torque is smaller than the value A, the LDA control is inhibited in some cases. This makes it difficult to execute the LDA control, making it difficult for the driver to feel that something abnormal is happening.

[0037] Note that even in the case where the inhibition threshold value Tsth is set to a smaller value when the specific object OV is present than when the specific object OV is not present, the inhibition threshold value Tsth can be set to a smaller value when the specific object OV is present and the driver performs the steering operation in the direction in which the host vehicle 8 avoids the specific object OV than when the specific object OV is present and the driver does not perform the steering operation in the direction in which the host vehicle 8 avoids the specific object OV.

[0038] When the unevenness of a road surface is large, a larger value is determined as the inhibition threshold Tsth than when the unevenness of the road surface were small. Since the steering wheel 24 and the steered road wheels are mechanically connected via the electric steering device 22 and other similar components, a road impact received by the steered road wheels is transmitted to the steering wheel 24. Thus, the absolute value of the steering torque Ts applied by the driver to hold the steering wheel 24 is large in the case where the unevenness of the road surface is large, the road impact received by the steered road wheels is large, and the external disturbance is large, as shown in Fig. 8B, is greater than in the case where the unevenness of the road surface is small, the road impact received by the steered road wheels is small and the external disturbance is small, as in Fig. 8A. If the inhibition threshold value Tsth in the case where the external disturbance is large is a value C which is Fig. As shown in Figure 8A, in some cases, due to road surface unevenness, the absolute value of the steering torque Ts exceeds the inhibition threshold Tsth without the driver's steering operation, resulting in inhibition of the LDA control. In the case where the threshold is set to a value B, which is Fig. 8B (which is larger than the value C), the LDA control is not inhibited in some cases even when the driver performs the steering operation to make the own vehicle 8 avoid the specific object OV, thereby making the driver feel that something abnormal is happening.

[0039] In the present embodiment, however, the inhibition threshold Tsth is increased when the degree of road surface roughness is large. This increase makes it difficult for the absolute value of the steering torque due to road impact to exceed the inhibition threshold Tsth, thereby making it difficult to inhibit LDA control regardless of the driver's intentions. When the degree of road surface roughness is small, the inhibition threshold Tsth is reduced. This reduction makes it less likely for the driver to feel that something abnormal is occurring.

[0040] The strength of the road impact as an external disturbance, in other words the degree of unevenness of the road surface, can be detected, for example, based on the steering torque. If the unevenness of the road surface is large, as in Fig. 8A and Fig. 8B, the amplitude of the steering torque and the maximum absolute value are larger than when the unevenness of the road surface were small. Thus, in the present embodiment, as shown in Fig. 8C, the maximum value Tsmax of the absolute value of the steering torque Ts within a set time period TP elapsed up to a current time P is detected as a value representing the degree of unevenness of the road surface.

[0041] The degree of unevenness of the road surface is recorded according to a program for detecting unevenness of a road surface, which is shown in the flow chart in Fig. 7. This flow begins with S31, where an absolute value |θ| of an operation angle of the steering wheel 24, detected by the operation angle sensor 28, is smaller than an operation angle threshold value θth close to zero. In other words, it is determined whether the steering wheel 24 substantially assumes the reference position and the host vehicle 8 is traveling straight. When the steering wheel 24 substantially assumes the reference position, the electric motor 21 applies no or very small steering torque, making it possible to detect a steering torque related to road impact. At S32, a value detected by the steering torque sensor 26 is stored. At S33, data is processed within the predetermined set time period TP. At S34, the maximum value Tsmax of the absolute value of the steering torque Ts within the set time period TP is detected.

[0042] In the present embodiment, when the maximum value Tsmax is greater than a road surface roughness determination threshold Tsx, it is determined that the external disturbance is large and the road surface roughness is large. Thus, the inhibition threshold Tsth is set to a large value. Note that filtering processing for removing low frequencies may be performed to remove a steering torque caused by a slow steering operation by the driver.

[0043] When a range is short, a smaller value is determined as the inhibition threshold Tsth than if the range were long. The range is a vehicle-object distance taking into account the relative speed. The range corresponds to the time tc until an expected encounter that the host vehicle 8 needs to collide with the object that has come within range. When the range (corresponding to the time until the expected encounter) is short, the host vehicle 8 needs to avoid the object that has come within range more quickly than if the range were long. Therefore, when the range is short, it is preferable to make the execution of LDA control more difficult. For example, in some cases, the object that has come within range is detected at an intersection or when another vehicle changes lanes.In these cases, the time until the expected encounter may become short. If the range tc is less than a set time period tcx (which may be referred to as the "set distance to an object coming within range"), the present embodiment determines that the range is short. Thus, the inhibition threshold Tsth is set to a small value.

[0044] Although the inhibition threshold value Tsth is determined as described above, in the present embodiment, higher priority is given to the road surface roughness than to the distance to an in-reach object. When the maximum value Tsmax of the absolute value of the steering torque is greater than the road surface roughness determination value Tsx, the inhibition threshold value Tsth is set to the value B regardless of the distance to an in-reach object. For example, in the case where the assumed road surface roughness is large, the value B may be a value slightly larger than the maximum value Tsmax of the absolute value of the steering torque. The value B is smaller than the value A.

[0045] When the maximum value Tsmax of the absolute value of the steering torque is less than or equal to the roughness determination value Tsx, the inhibition threshold Tsth is determined based on the distance to an object coming within range. When the range tc is less than the set time tcx, the inhibition threshold Tsth is set to the value C. When the range tc is greater than or equal to the set time tcx, the inhibition threshold Tsth is set to the value B. The value C may be a value easily achievable when the steering operation is performed by the driver. The value C may be less than the value B. In the case where the inhibition threshold Tsth is set to the value C, the LDA control is more likely to be inhibited and less likely to be executed.

[0046] The inhibition threshold Tsth is determined by executing the threshold determination program. Fig. Figure 4A is a flowchart illustrating a flow of the threshold determination program. The flow begins at S40, where the environmental information is read. At S41, information about road surface unevenness (the maximum torque value Tsmax) and the steering direction flag Fs are read. At S42, it is determined whether the specific object OV is present. If the specific object OV is not present, the inhibition threshold Tsth is set to the value A at S44. Since the specific object OV is not present, LDA control is more easily executed.

[0047] If the specific object OV is present, it is determined at S43 whether the driver has performed the steering operation in the direction in which the host vehicle 8 avoids the specific object OV (note that this operation is hereinafter referred to as “evasive steering operation”). As shown in Fig. 4B, it is determined at S43a and S43b whether the specific object OV is located on a front right side or a front left side of the own vehicle 8. If the specific object OV is located on a front right side of the own vehicle 8, it is determined at S43c whether the steering direction flag Fs is 1. That is, it is determined whether the steering wheel 24 is operated in the left direction. If the specific object OV is located on a front left side of the own vehicle 8, it is determined at S43d whether the steering direction flag Fs is 2. That is, it is determined whether the steering wheel 24 is operated in the right direction. If a negative decision (NO) is made at S43c or S43d, it is determined at S43e that the driver is performing the steering operation to move the own vehicle 8 away from the specific object OV, that is,the steering operation in the direction in which the own vehicle 8 avoids the specific object OV has not been carried out.

[0048] If an affirmative decision (YES) is made at S43c or S43d, it is determined at S43f that the driver performed the steering operation to move the host vehicle 8 away from the specific object OV, that is, the evasive steering operation. If the object side distance dv is smaller than the second object side distance dvth2, negative decisions are made at S43a and S43b. It is determined that the specific object OV is in front of the host vehicle 8. If the steering direction flag Fs is 1 or 2, an affirmative decision (YES) is made at S43g, and it is determined at S43f that the driver performed the evasive steering operation to avoid the specific object OV. However, if the steering direction flag Fs is 0 and the host vehicle 8 is decelerating, a negative decision (NO) is made at S43g, and it is determined that the evasive steering operation has not been performed.

[0049] If the evasive steering operation is not performed even though the specific object OV is present, the inhibition threshold Tsth is set to the value A at step S44. This is because the driver does not feel that something abnormal is occurring even though the LDA control is being performed. When the evasive steering operation is performed, the processing at step S45 and the following steps is executed. If the LDA control is being performed, the driver feels that something abnormal is occurring. Thus, the inhibition threshold Tsth is set to a value smaller than the value A to make the execution of the LDA control difficult.

[0050] At S45, it is determined whether the degree of road surface roughness is large. That is, it is determined whether the maximum value Tsmax of the absolute value of the steering torque is greater than the road surface roughness determination value Tsx. If it is determined that the road surface roughness is large, the inhibition threshold Tsth is set to B at S46. That is, the inhibition threshold Tsth is set to a value that is not easily exceeded by the absolute value of the steering torque caused by the road impact, thereby making it difficult to inhibit the LDA control, contrary to the driver's intention.

[0051] If the maximum value Tsmax of the steering torque is less than or equal to the determination value Tsx for the roughness of the road surface, it is determined at S47 whether the in-reach object is present. If the in-reach object is present, it is determined at S48 whether the in-reach distance, that is, the time tc until the expected encounter, is shorter than the set time tcx. If the in-reach object is not present or if the time tc until the expected encounter is longer than or equal to the set time tcx, the inhibition threshold Tsth is set to the value B at S46. If the time tc until the expected encounter that the host vehicle 8 takes to collide with the in-reach object is less than the set time tcx, the inhibition threshold Tsth is set to the small value C at S49.That is, LDA control is more likely to be inhibited and less likely to be executed.

[0052] In the present embodiment described above, when the specific object OV is present and the driver has performed the steering operation to operate the host vehicle 8 to avoid the specific object OV, the LDA control is more easily inhibited. That is, execution of the LDA control is made more difficult, and the driver is less likely to feel that something abnormal is happening. Even when the range is short, the inhibition threshold Tsth is set to a small value. Thus, when the driver has performed the steering operation to operate the host vehicle 8 to avoid the specific object OV, the LDA control is much more easily inhibited, and the driver is less likely to feel that something abnormal is happening.Likewise, the inhibition threshold Tsth is determined based on the degree of roughness of the road surface, which makes it less likely that a situation occurs where the absolute value of the steering torque received due to the road impact exceeds the inhibition threshold Tsth, thereby making it difficult to inhibit the LDA control contrary to the driver's intention.

[0053] The electric steering assist device 22 is an example of an assist device. The driving assist device is constituted by devices and components including the electric steering assist device 22, the steering torque sensor 26, the driving assist ECU 10, and the camera 40. An assist control device is constituted by devices including the LDA control device 46 and the steering ECU 12. An assist inhibit device is constituted by devices including the LDA control device 48 and the steering torque sensor 26.

[0054] A threshold value determination device is provided by sections of the driving support ECU 10 in Fig. 4A, in which the threshold value determination program is stored and executed. Both an external disturbance-dependent threshold value determination device and a road surface irregularity-dependent threshold value determination device consist of sections of the driving support ECU 10 in which the processing at S45, S46 and S49 in the threshold value determination program are carried out in Fig. 4A are stored and executed. A threshold value determination device dependent on an object coming into range is formed by sections of the driving support ECU 10 in which the processing at S47, S48, S46, and S49 is stored and executed. Both an external disturbance detection device and a road surface unevenness detection device are formed, for example, by the steering torque sensor 26 and sections of the driving support ECU 10 in which the road surface unevenness detection program is stored. Fig. 7 is stored and executed. The determination threshold for road surface roughness is an example of a set value for external disturbances. The steering torque is an example of a steering operation value.

[0055] The inhibition threshold Tsth takes one of the three values ​​in the above-described embodiment, but may also take one of four or more values, or may be continuously changed based on a value representative of the degree of roughness of the road surface (e.g., the maximum value Tsmax of the steering torque) or based on the range tc. In the case where a crosswind blows against the host vehicle 8 as an external disturbance, a degree of the crosswind may be used instead of the roughness of the road surface. For example, if the absolute value of the steering angle of the steering wheel 24 is small and the absolute value of the steering torque is large, it can be assumed that the crosswind is strong, and the value B can be determined as the inhibition threshold Tsth.

[0056] The driving assistance device in the present embodiment includes a plurality of computers, but may also include a single computer. Although the camera is an example of an object information acquiring device in the present embodiment, the object information acquiring device may include the camera and / or a radar device. For example, the image captured by the camera and a signal acquired by the radar device are examples of object information. For example, the environment acquiring device may be configured to acquire an environment in the area identified based on an image captured by the camera and / or a laser or a signal output from the radar device. Second embodiment

[0057] It is not essential to determine the inhibition threshold Tsth based on the presence or absence of the specific object OV, the presence or absence of the evasive steering operation, the road surface roughness, and / or the distance to an object that has come within range. As in Fig. As shown in Fig. 11, the inhibition threshold Tsth can be determined, for example, based on the presence or absence of the specific object OV, the presence or absence of the evasive steering operation, and the road surface unevenness. In the present embodiment, when the specific object OV is present and the evasive steering operation is performed, and the road surface unevenness is large, the inhibition threshold Tsth is set to the value B at S46. When the specific object OV is present and the evasive steering operation is performed, and the road surface unevenness is small, the inhibition threshold Tsth is set to the value C at S49.

[0058] As in Fig. As shown in Figure 12, the inhibition threshold Tsth can be determined, for example, based on the presence or absence of the specific object OV, the presence or absence of the evasive steering operation, and the driving range. In the present embodiment, when the specific object OV is present and the evasive steering operation is performed, and the driving range is long, the inhibition threshold Tsth is set to the value B at S46. When the specific object OV is present and the evasive steering operation is performed, and the driving range is short, the inhibition threshold Tsth is set to the value C at S49.

[0059] As in Fig. 13, the inhibition threshold Tsth can be determined, for example, based on the presence or absence of the specific object OV and the presence or absence of the evasive steering operation. When the specific object OV is not present, or when the specific object OV is present and the evasive steering operation is not performed, the inhibition threshold Tsth is set to the value A at S43. When the specific object OV is present and the evasive steering operation is performed, the inhibition threshold Tsth is set to the value C at S49x.

[0060] If the specific object OV is present, as in Fig. 14, the inhibition threshold value Tsth is set to B or C at S49x, regardless of the presence or absence of the steering operation performed by the driver to operate the host vehicle 8 to avoid the specific object OV. If the specific object OV is not present, the inhibition threshold value Tsth is set to A at S44.

[0061] Please note that the processing at S43 is carried out in the Fig. 4 and 11-13 is not essential. Likewise, the inhibition threshold need not be determined based on the presence or absence of the evasive steering operation performed by the driver, and in this case, the evasive steering operation may be added to a condition for setting the abort flag. Third embodiment

[0062] In the above-described embodiment, the assist device is the electric steering assist device 22, etc., but may also be the notification device 14. For example, in the case where the notification device 14 is a device configured to generate sounds and / or voices, a device configured to illuminate or flash a light, or a display, a notification operation performed by the notification device 14 is made difficult, thereby reducing the driver's discomfort.

[0063] However, it is known that in the case where the notification device 14 is configured to generate sounds and speech, the driver is more concerned about the sounds and speech heard by a passenger or passengers (at least one passenger other than the driver) than about disturbing the driver. Therefore, in the case where no passenger is present, it is considered that there is little need to make the operation of the notification device 14, i.e., the execution of the LDA control, difficult. Given the circumstances described above, in the case where the support device is the notification device 14 configured to generate sounds and speech, the operation of making the execution of the LDA control difficult is preferably performed only when at least one passenger is present.Whether (at least) one passenger is present is determined by the occupancy sensors 17b, which are each provided for the passenger seats 17y provided in the own vehicle 8.

[0064] Fig. 15 is a flowchart illustrating a procedure for an example of this case. The surrounding information is read at S50. Values ​​detected by the respective occupancy sensors 17b are read at S51. At S52, it is determined whether the specific object OV is present. If the specific object OV is present, it is determined at S53 whether the evasive steering operation is performed. If the evasive steering operation is performed, it is determined at S54 whether a passenger is present based on the values ​​detected by the occupancy sensors 17b. That is, it is determined whether a person is present in the host vehicle 8 in addition to the driver. For example, if none of the occupancy sensors 17b detects occupancy by a person, it is determined that no passenger is present, and a negative decision (NO) is made, and the inhibition threshold Tsth is set to the value A at S55.If at least one of the occupancy sensors 17b detects occupancy by a person, the inhibition threshold value Tsth is set to the value B or C at S56.

[0065] In the present embodiment, the inhibition threshold Tsth is reduced as described above when the specific object OV and at least one passenger are present. With this reduction, the (at least) one passenger is less likely to feel that something unusual is happening, which in turn lessens the driver's disturbance. In the present embodiment, a passenger-dependent threshold determination means is formed by the occupancy detector 17 and sections of the driving support ECU 10 in which the processings at S51 and S54-S56 are stored and executed in the threshold determination program in Fig. 15 are executed.

[0066] In the case where the notification device 14 is configured to use body sensations due to a vibration of the steering wheel 24, a vibration of a seat belt (not shown), or a vibration of the driver's seat to notify that there is a probability of the host vehicle 8 deviating from the lane, it is assumed that there is little need to make the execution of the LDA control difficult even when, for example, the specific object OV is present. Therefore, in the case where the notification device 14 is a device configured to use body sensations to notify that there is a probability of deviating from a lane, it is possible, for example, to prevent the inhibition threshold Tsth from decreasing even when the specific object OV is present.

[0067] For example, in the case where the notification device 14 is designed to generate sounds or speech, the inhibition threshold Tsth may be set to the fixed value A regardless of the presence or absence of the specific object OV. Note that the processing at S53 is not essential. Fourth embodiment

[0068] It is not essential to consider the presence or absence of the specific object OV to determine the inhibition threshold Tsth. The inhibition threshold Tsth can be determined based on the unevenness of the road surface. Fig. 16 is a flowchart illustrating a procedure for an example of this case. In the present embodiment, the situation of the unevenness of the road surface is detected at S61. At S62, it is determined whether the degree of unevenness of the road surface is large. If the degree of unevenness of the road surface is small, the inhibition threshold Tsth is set to the value B or C at S64. If the unevenness of the road surface is large, the inhibition threshold Tsth is set to the value A at S63. Also, in the present embodiment, even when the unevenness of the road surface is large and a change in the steering torque due to the external disturbance is large, it is possible to accurately determine whether the steering operation is performed by the driver, thereby making it difficult to inhibit the LDA control contrary to the driver's intention.In the present embodiment, a road surface unevenness-dependent threshold determining means is constituted by, for example, sections of the driving support ECU 10 in which the threshold determining program in . Fig. 16 is saved and executed.

[0069] Despite the embodiments described above, it should be understood that the invention is not limited to the details of the illustrated embodiments, but may be embodied with various changes and modifications that may be obvious to a person skilled in the art without departing from the spirit and scope of the invention. CLAIMABLE INVENTIONS

[0070] Claimable inventions in the following forms are now described. (1) A driving assistance device designed to provide driving assistance in such a way that an own vehicle travels within a lane, the driving assistance device comprising: an object information acquisition device configured to acquire object information relating to at least one object in an area; an environment detection device configured to detect a relative positional relationship between the host vehicle and the object located in the area and identified on the basis of the object information detected by the object information detection device; and an assistance inhibition device designed to inhibit driving assistance when an absolute value of a steering operation value representing an amount of steering operation performed by a driver is greater than an inhibition threshold value, wherein the assist inhibition means comprises a threshold value determining means configured to determine a smaller value as the inhibition threshold value when the relative positional relationship between the object and the host vehicle detected by the surroundings detecting means is a specific relationship in which it is assumed that the driver will perform a steering operation in a direction in which the host vehicle avoids the object than when the relative positional relationship between the object and the host vehicle detected by the surroundings detecting means is not the specific relationship.

[0071] The driving assistance device may include a departure prevention assistance device configured to assist driving that prevents the host vehicle from departing from the lane, and a lane maintenance assistance device configured to assist driving in which the host vehicle travels along a target driving line substantially in the center of the lane. Examples of the steering operation value include: a steering torque produced by a driver's operation of the steering operation element; a steering force; a value representing a speed at which the steering operation element is operated; and a value representing a degree of steering of the steering operation element. Examples of the object include a vehicle, a person, a guardrail, and a wall.Note that examples of the case where the relative positional relationship between the object and the own vehicle is not the specific relationship include, among others: a case where the relative positional relationship is not the specific positional relationship even if the object is present in the area according to the object information acquired by the object information acquiring means; and a case where no object is present in the area according to the object information acquired by the object information acquiring means.

[0072] (2) The driving assistance device according to the above-mentioned form (1), wherein the threshold value determining means comprises an in-reach object-dependent threshold value determining means configured to determine a smaller value as the inhibition threshold value when a time expected for the own vehicle to collide with an in-reach object, that is, an object first detected by the surroundings detecting means, is short than when the time expected for the own vehicle to collide with the in-reach object is long.

[0073] The in-range object threshold determining device may include an in-range object detector configured to detect the in-range object. A relative positional relationship between the in-range object and the host vehicle is typically the specific relationship. In many cases, the in-range object comes within range, for example, at an intersection or when another vehicle changes lanes. In a case where the expected time for the host vehicle to collide with the in-range object is short, the driver feels that the host vehicle must urgently operate to avoid the in-range object. Thus, it is even more preferable to make the execution of driving assistance more difficult.

[0074] (3) The driving support device according to the above form (1) or (2), wherein the threshold determining means comprises: an external disturbance detection device designed to detect the intensity of an external disturbance affecting the vehicle; and an external disturbance-dependent threshold determining device which is designed to determine a larger value as the inhibition threshold when the strength of the external disturbance detected by the external disturbance detecting device is large than when the strength of the external disturbance detected by the external disturbance detecting device is small.

[0075] Examples of external disturbances include uneven road surfaces and crosswinds. External disturbances affect the steering effort. In many cases, it is difficult to distinguish whether the absolute value of the steering effort exceeded the inhibition threshold due to the external disturbance or due to the driver's steering effort.

[0076] (4) The driving assistance device according to the above form (3), wherein the vehicle has a steering mechanism that mechanically couples a steered wheel and a steering actuating element that can be actuated by the driver, wherein the driving assistance device further comprises a steering torque sensor configured to detect a steering torque applied by the driver to the steering mechanism via the steering actuating element, and wherein the external disturbance detection device is configured to detect a larger unevenness of the road surface in a situation where the steering operating element substantially occupies a reference position when an absolute value of a value detected by the steering torque sensor is large than when the absolute value of the element detected by the steering torque sensor is small.

[0077] For example, in the case where the road surface is uneven and the external disturbance such as road impact is large, or in the case where a crosswind is strong and the external disturbance is large, the driver applies a large steering torque to hold the steering actuator. Thus, it can be assumed that in a situation where the steering actuator substantially assumes the reference position, in other words, in a situation where the vehicle substantially travels straight, the external disturbance is greater when the absolute value of the steering torque is large than when the absolute value of the steering torque is small. The steering actuator assumes the reference position when the vehicle travels straight.When the steering operation member occupies the reference position, an absolute value of a value detected by an operation amount sensor configured to detect an operation amount of the steering operation member is less than or equal to an operation amount threshold. Large road surface unevenness means a large difference in the height of the bumps. For example, the severity of the road impact due to road surface unevenness is greater when the difference in the height of the bumps is large than when the difference in the height of the bumps is small. Thus, the degree of road surface unevenness can be represented as the severity of the road impact.

[0078] Note that the degree of unevenness of the road surface can also be detected based on an image taken by a camera, for example.

[0079] (5) The driving support device according to the above form (3) or (4), wherein the external disturbance dependent threshold determining means is configured to, when the relative positional relationship between the object and the own vehicle detected by the environment detecting means is the specific relationship, determine, as the inhibition threshold, a value which is larger when the level of external disturbance is large than when the level of external disturbance is small.

[0080] As the inhibition threshold value taken in the case where the external disturbance is large, a value smaller than the inhibition threshold value taken in the case where the relative positional relationship between the object and the own vehicle is not the specific relationship is determined.

[0081] (6) The driving assistance device according to the above form (5), wherein the threshold value determination device dependent on an external disturbance is designed to determine a greater value as the inhibition threshold when the strength of the external disturbance detected by the device for detecting an external disturbance is greater than a set value for the external disturbance than when the strength of the external disturbance detected by the device for detecting an external disturbance is less than or equal to the set value for the external disturbance, wherein the threshold value determining device comprises a threshold value determining device dependent on an object that has come into range, which is designed to set a smaller value as the inhibition threshold when the object whose relative positional relationship with the own vehicle is the specific relationship is an object that has come into range, that is, an object that is first detected by the environment detection device, and when a time that the own vehicle is expected to take to collide with the object that has come into range is short than when the time that the own vehicle is expected to take to collide with the object that has come into range is long, and wherein the threshold value determination device dependent on an object that has come into range is designed, when the level of external interference detected by the device for detecting external interference is less than or equal to the set value for the external interference, to determine a smaller value as the inhibition threshold value if the time that the vehicle is expected to need to collide with the object that has come into range is short, than if the time that the vehicle is expected to need to collide with the object that has come into range would be long.

[0082] The threshold determination device dependent on external interference is given higher priority than the threshold determination device dependent on an object coming within range. If the level of external interference is greater than the set value of the external interference, a large value is set as the inhibition threshold, regardless of the time until the expected encounter. The situation where the strength of the external interference is greater than the set value of the external interference is a situation where the steering operation value is strongly influenced by the external interference, and therefore there is a high probability that the external interference will cause the absolute value of the steering operation value to become greater than the inhibition threshold. Therefore, it is advisable to set a large value as the inhibition threshold, regardless of the time until the expected encounter.In contrast, the situation where the external disturbance intensity is less than or equal to the set external disturbance value is a situation where the effect of the external disturbance on the steering operation value is small, and even if the inhibition threshold is small, there is little likelihood of the absolute value of the steering operation value exceeding the inhibition threshold due to the external disturbance. Therefore, it is appropriate for the inhibition threshold to be determined by the threshold determination device depending on the object that has come into reach, and it is possible to accurately determine whether the absolute value of the steering operation value exceeds the inhibition threshold due to the steering operation performed by the driver.

[0083] (7) The driving assistance device according to the above form (6), wherein the in-reach object-dependent threshold determining means is configured to, when the time expected for the own vehicle to collide with the in-reach object is longer than a set time until the expected collision, determine, as an inhibition threshold, a value smaller than or equal to the inhibition threshold determined by the external disturbance-dependent threshold determining means when the level of the external disturbance is greater than the set value for the external disturbance.

[0084] (8) The driving assistance device according to any one of the above forms (3) to (7), wherein the external disturbance detection means comprises a road surface unevenness detection means configured to detect a degree of unevenness of a road surface on which the host vehicle is traveling, and wherein the external disturbance-dependent threshold determining means comprises a road surface unevenness-dependent threshold determining means configured to determine a larger value as the inhibition threshold when the degree of road surface unevenness detected by the road surface unevenness detecting means is large than when the degree of road surface unevenness detected by the road surface unevenness detecting means is small.

[0085] (9) The driving assistance device according to any one of the above forms (1) to (8), wherein the threshold value determining means is configured to, when the relative positional relationship is (i) a relationship in which an object side distance, that is, a distance between the object and a lane line defining a lane on which the subject vehicle is traveling, is less than or equal to a set object side distance, and (ii) (a) a relationship in which a vehicle-to-object distance between the object and the subject vehicle is less than or equal to a set vehicle-to-object distance, and / or (b) a relationship in which the subject vehicle is approaching the object at a speed higher than or equal to a set speed, determine that the relative positional relationship is the specific relationship, and to determine a smaller value as the inhibition threshold value than then,if the relative positional relationship is not the specific relationship.,

[0086] (10) The driving assistance device according to any one of the above forms (1) to (9), wherein the threshold value determining means is configured to determine, as the inhibition threshold value, a smaller value when the relative positional relationship is the specific positional relationship and the steering operation is performed by the driver in the direction in which the own vehicle avoids the object than when the steering operation is not performed by the driver.

[0087] It is expected that the driver will feel that something abnormal is occurring when the driving assistance is performed in the case where the driver has performed the steering operation in the direction in which the host vehicle is avoiding the object. To solve this problem, a small value is set as the inhibition threshold to make it difficult to perform the driving assistance, thereby making it less likely for the driver to feel that something abnormal is occurring. Steering operation state detection means detects information indicating that the driver has performed the steering operation in the direction in which the host vehicle is avoiding the object. In the embodiment described above, the steering operation state detection means is constituted by, for example, the steering torque sensor 26, the steering direction flag Fa, and the steering ECU 12 configured to set the steering direction flag Fa.

[0088] (11) The driving support device according to any one of the above forms (1) to (10), further comprising: an assistance device designed to perform the driving assistance; and an assistance control device configured to control the assistance device to perform the driving assistance.

[0089] (12) The driving assistance device according to the above form (11), wherein the assist device comprises an electric driving assist device provided between a steering operating member and a wheel and having an electric motor, and wherein the assistance control device is designed, when there is a probability that the vehicle will deviate from the lane, to control the electric motor so that it applies a steering torque in a direction in which the deviation of the own vehicle from the lane is prevented.

[0090] The wheel corresponds to the steered wheel.

[0091] (13) A driving assistance device according to the above form (11) or (12), wherein the assistance device does not have a notification device that uses a body sensation of the driver to indicate that the probability that the own vehicle will deviate from the lane is high

[0092] (14) The driving assistance device according to any one of the above forms (11) to (13), wherein the support device comprises a notification device configured to produce a sound to issue a notification of a high probability that the host vehicle will deviate from the lane, wherein the host vehicle has a plurality of seats including: a driver's seat and at least one passenger seat different from the driver's seat. wherein the driving support device further comprises a plurality of occupancy detectors each provided for the plurality of seats and each configured to detect whether a person is sitting thereon, and wherein the threshold value determination device comprises a passenger-dependent threshold value determination device which is designed to determine a greater value as the inhibition threshold value when the plurality of occupancy detectors do not determine that a person is sitting on the at least one passenger seat than when at least one corresponding one of the plurality of occupancy detectors determines that a person is sitting on at least one of the passenger seats.

[0093] (15) The driving assistance device according to the above form (14), wherein the passenger-dependent threshold determining means is configured to, when it is not detected by the plurality of occupancy detectors that a person is sitting on the at least one passenger seat, determine, as the inhibition threshold, a value equal to an inhibition threshold taken when the relative positional relationship between the object and the own vehicle is not the specific positional relationship.

[0094] (16) A driving assistance device designed to provide driving assistance in such a way that an own vehicle travels within a lane, the driving assistance device comprising: an assistance inhibition device configured to inhibit driving assistance when an absolute value of a steering operation value representing an amount of steering operation performed by a driver is greater than an inhibition threshold; wherein the support inhibition device comprises: a road surface unevenness detection device designed to detect a degree of unevenness of a road surface on which the own vehicle is traveling; and a road surface unevenness threshold determining means configured to determine a larger value as the inhibition threshold when the degree of road surface unevenness detected by the road surface unevenness detecting means is large than when the degree of road surface unevenness detected by the road surface unevenness detecting means is small.

[0095] Examples of the steering operation value from the examples of the steering operation value in this form described above include, for example, the steering torque applied by the driver to the steering mechanism and the steering force. The technical features in forms (1)-(15) can be incorporated into the driving assistance device according to this form.

[0096] (17) A driving assistance device designed to provide driving assistance in such a way that a vehicle of its own travels within a lane, wherein the driving assistance device comprises an assistance inhibition device configured to inhibit the driving assistance when an absolute value of a steering operation value is greater than an inhibition threshold value; wherein the support inhibition device comprises: an external disturbance detection device designed to detect the intensity of an external disturbance applied to the vehicle; and An external disturbance threshold determining device configured to determine a larger value as the inhibition threshold when the intensity of the external disturbance detected by the external disturbance detecting device is large than when the intensity of the external disturbance detected by the external disturbance detecting device is small. The technical features in forms (1)-(15) can be incorporated into the driving assistance device according to this form. The external disturbance is, for example, an uneven road surface and / or a crosswind, and so on.

Claims

[1] Driving assistance device (22, 26, 10, 14, 40) designed to carry out driving assistance in such a way that an own vehicle (8) travels within a lane, the driving assistance device (22, 26, 10, 14, 40) comprising: an object information acquisition device (40) configured to acquire object information relating to at least one object in an area; an environment detection device (42) designed to detect a relative positional relationship between the host vehicle (8) and the object located in the area and identified on the basis of the object information detected by the object information detection device (42); and an assistance inhibiting device (10, 26, 17) configured to inhibit the driving assistance when an absolute value of a steering operation value representing an amount of steering operation performed by a driver is greater than an inhibition threshold value (Tsth); wherein the assistance inhibition device (10, 26, 17) comprises a threshold value determination device (10, 17) which is designed, when the relative positional relationship between the object and the host vehicle (8) detected by the environment detection device (42) is a specific relationship in which it is anticipated that the driver will perform a steering operation in a direction in which the host vehicle (8) avoids the object, to determine a smaller value as the inhibition threshold value (Tsth) than if the relative positional relationship between the object and the host vehicle (8) detected by the environment detection device (42) were not the specific relationship, wherein the threshold value determination device (10, 17) comprises: an external disturbance detection device (10, 26) designed to detect the intensity of an external disturbance acting on the host vehicle (8); and an external disturbance-dependent threshold value determination device (10, 17) which is designed to determine a larger value as the inhibition threshold value (Tsth) when the strength of the external disturbance detected by the external disturbance detection device (10, 26) is large than when the strength of the external disturbance detected by the external disturbance detection device (10, 26) is small, wherein the threshold value determination device (10, 17) dependent on an external disturbance is designed to determine a larger value as the inhibition threshold value (Tsth) when the strength of the external disturbance detected by the device (10, 26) for detecting an external disturbance is greater than a set value for the external disturbance than when the strength of the external disturbance detected by the device (10, 26) for detecting an external disturbance is less than or equal to the set value for the external disturbance, wherein the threshold value determination device (10, 17) comprises a threshold value determination device (10, 17) dependent on an object that has come into range, which is designed to determine a smaller value as the inhibition threshold value (Tsth) when a time that the own vehicle (8) is expected to need to collide with an object that has come into range, which is an object that is first detected by the environment detection device (42), is short than if the time that the own vehicle (8) is expected to need to collide with the object that has come into range would be long, and wherein the threshold value determination device (10, 17) dependent on an object that has come into range is designed, when the strength of the external interference detected by the device (10, 26) for detecting an external interference is less than or equal to the set value for the external interference, to determine a smaller value as the inhibition threshold value (Tsth) when the time that the host vehicle (8) is expected to need to collide with the object that has come into range is short than when the time that the host vehicle (8) is expected to need to collide with the object that has come into range is long. [2] The driving assistance device (22, 26, 10, 14, 40) according to claim 1, wherein the threshold value determining device (10, 17) comprises an in-range object dependent threshold value determining device (10, 17) which is designed to determine a smaller value as the inhibition threshold value (Tsth) when a time which the own vehicle (8) is expected to take to collide with an in-range object, which is an object which is first detected by the surroundings detection device (42), is short than when the time which the own vehicle (8) is expected to take to collide with the in-range object would be long. [3] The driving assistance device (22, 26, 10, 14, 40) according to claim 1, wherein the external disturbance-dependent threshold value determining device (10, 17) is designed to determine, when the relative positional relationship between the object and the host vehicle (8) detected by the environment detecting device (42) is the specific relationship, as the inhibition threshold value (Tsth), a value which, when the level of the external disturbance is high, is larger than when the level of the external disturbance would be small, and which, when the relative positional relationship is the specific positional relationship, is smaller than when the relative positional relationship would not be the specific positional relationship. [4] Driving assistance device (22, 26, 10, 14, 40) according to one of claims 1 to 3, wherein the external disturbance detection device (10, 26) comprises a road surface unevenness detection device (10, 26) configured to detect a degree of unevenness of a road surface on which the host vehicle (8) is traveling, and wherein the external disturbance-dependent threshold determining means (10, 17) comprises a road surface unevenness-dependent threshold determining means (10, 17) configured to determine a larger value as the inhibition threshold (Tsth) when the degree of road surface unevenness detected by the road surface unevenness detecting means (10, 26) is large than when the degree of road surface unevenness detected by the road surface unevenness detecting means (10, 26) is small. [5] Driving assistance device (22, 26, 10, 14, 40) according to one of claims 1 to 4, wherein the threshold value determining device (10, 17) is designed to determine that the relative positional relationship is the specific relationship when the relative positional relationship is (i) a relationship in which an object lateral distance (dv), i.e., a distance between the object and a lane line defining a lane on which the own vehicle travels, is less than or equal to a set object lateral distance (dvth1), and (ii) (a) a relationship in which a vehicle-to-object distance (L) between the object and the own vehicle (8) is less than or equal to a set vehicle-to-object distance (Lth), and / or (b) a relationship in which the own vehicle (8) approaches the object at a speed greater than or equal to a set speed,and to determine a smaller value as the inhibition threshold (Tsth) than when the relative positional relationship is not the specific relationship. [6] Driving assistance device (22, 26, 10, 14, 40) according to one of claims 1 to 5, wherein the threshold value determining means (10, 17) is designed to determine a smaller value as the inhibition threshold value (Tsth) when the relative positional relationship is the specific positional relationship and the driver performs the steering operation in the direction in which the own vehicle (8) avoids the object than when the driver does not perform the steering operation. [7] Driving assistance device (22, 26, 10, 14, 40) according to one of claims 1 to 6, further comprising: a support device (22, 14) designed to perform the driving support; and an assistance control device (46, 12) designed to control the assistance device (22, 14) so ​​that it carries out the driving assistance, wherein the support device (22, 14) comprises a notification device (14) designed to produce a sound to output a message about a high probability that the host vehicle (8) will deviate from the lane, wherein the own vehicle (8) has a plurality of seats (17x, 17y) comprising: a driver's seat (17x) and at least one passenger seat (17y) different from the driver's seat (17x), wherein the driving support device (22, 26, 10, 14, 40) further comprises a plurality of occupancy detectors (17) each provided for the plurality of seats and each configured to detect whether a person is sitting thereon, and wherein the threshold value determination device (10, 17) comprises a passenger-dependent threshold value determination device (17, 10) which is designed to determine a greater value as the inhibition threshold value (Tsth) when it is not determined by the plurality of occupancy detectors (17) that a person is sitting on the at least one passenger seat (17y) than when it is determined by at least one corresponding one of the plurality of occupancy detectors (17) that a person is sitting on at least one of the passenger seats (17y).

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