Driving assistance method and driving assistance device

Abstract

A driving assistance method and a driving assistance device (14) acquire a steering direction of a steered wheel of a vehicle (V), and set a left threshold value when a steering wheel is rotated in a left direction and a right threshold value when the steering wheel is rotated in a right direction as threshold values for cancelling autonomous steering control of the vehicle (V). When the absolute value of the torque input to the steering wheel exceeds the left threshold value or the right threshold value, the autonomous steering control is released, when the steering direction is the left direction, the right threshold value is greater than the left threshold value, and when the steering direction is the right direction, the right threshold value is greater than the left threshold value, and when the steering direction is the right direction, the right threshold value is greater than the left threshold value. The left threshold value is greater than the right threshold value.

Description

Technical Field

[0001] The invention relates to a driving assistance method and a driving assistance device. Background Art

[0002] A steering assist device is known that stops lane change assist control when it is determined that an input value based on a driver's steering operation exceeds an overriding threshold value during the execution of lane change assist control (Patent Document 1). In the steering assist device, a forward threshold value in the direction in which the vehicle changes lanes and a reverse threshold value in the direction opposite to the forward threshold value are set as overriding threshold values, and the magnitude of the reverse threshold value is set to be smaller than the magnitude of the forward threshold value until the end of the vehicle on the lane change side crosses the boundary between the original lane and the target lane.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6819876

[0006] Problems to be solved by the invention

[0007] In the case of a system that rotates the steering wheel according to the steering angle, a force that resists the action of rotating the steering wheel is generated in the steering system including the steering wheel. When the steering wheel is controlled by the steering actuator to turn the steering wheel, this resistance is detected by the torque sensor as a torque in the opposite direction to the turning direction of the vehicle. Therefore, even if the driver does not operate the steering wheel, it is recognized that the torque in the opposite direction to the turning direction of the vehicle is input from the steering wheel.

[0008] In the above-mentioned prior art, there is the following problem: since the reverse threshold is set to be smaller than the forward threshold, if the forward threshold is set to be smaller in order to smoothly switch to the driver's manual driving, the absolute value of the torque caused by the resistance in the above-mentioned steering system will exceed the reverse threshold, and the autonomous steering control will be erroneously released regardless of the driver's steering operation. Summary of the invention

[0009] An object of the present invention is to provide a driving assistance method and a driving assistance device capable of suppressing the autonomous steering control from being erroneously released independently of the steering operation of the driver.

[0010] The present invention solves the above-mentioned problem through the following processing: setting a left threshold value when the steering wheel of the vehicle is rotated to the left and a right threshold value when it is rotated to the right as thresholds for releasing the autonomous steering control of the vehicle; when the steering direction of the steering wheel of the vehicle is to the left, the right threshold value is made larger than the left threshold value; when the steering direction is to the right, the left threshold value is made larger than the right threshold value.

[0011] Effects of the Invention

[0012] According to the present invention, it is possible to suppress the autonomous steering control from being erroneously released regardless of the steering operation by the driver. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a block diagram showing an example of a driving assistance system including the driving assistance device of the present invention.

[0014] Figure 2 It means use Figure 1 A plan view of an example of a driving scene in which a driving assistance system performs driving assistance, and a diagram showing a steering torque detected in the driving scene.

[0015] Figure 3 This is a diagram showing an example of resistance generated in a steering system when a vehicle turns.

[0016] Figure 4 Yes means Figure 1 A flowchart of an example of the processing sequence in the driving assistance system.

[0017] Figure 5 Yes means Figure 1 A flowchart of another example of the processing sequence in the driving assistance system. DETAILED DESCRIPTION

[0018] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0019] (Structure of driver assistance system)

[0020] Figure 1 : is a block diagram showing the driving assistance system 1 of the present invention. The driving assistance system 1 is a vehicle-mounted system that drives the vehicle to a destination set by the vehicle's occupants through autonomous driving control. Autonomous driving control refers to autonomously controlling the vehicle's driving movements using a driving assistance device described later, and the driving movements include all driving movements such as acceleration, deceleration, starting, parking, turning to the right or left, etc. Autonomous control of driving movements refers to the driving assistance device controlling the driving movements using the vehicle's devices. The driving assistance device controls these driving movements within a pre-set range, and the driver performs manual operations for driving movements that are not controlled by the driving assistance device.

[0021] like Figure 1As shown, the driving assistance system 1 includes: a camera device 11, a vehicle state detection device 12, a steering control device 13 and a driving assistance device 14. In addition, in order to perform autonomous driving control, the driving assistance system 1 may also include a distance measuring device, map information, a vehicle position detection device, a navigation device, a display device and a speed control device (not shown). The devices constituting the driving assistance system 1 are connected via CAN (Controller Area Network) and other vehicle-mounted LANs, and can send and receive information to each other.

[0022] The camera device 11 is a device for recognizing objects around the vehicle through images, and is, for example, a camera having an image pickup element such as a CCD, an ultrasonic camera, an infrared camera, etc. In order to reduce blind spots when recognizing objects, a plurality of camera devices 11 may be provided on a single vehicle, for example, they may be arranged at the front grille of the vehicle, the lower part of the left and right door mirrors, and near the rear bumper.

[0023] The objects detected by the camera device 11 include: lane boundaries, center lines, road markings, central dividers, guardrails, curbs, side walls of highways, road markings, traffic lights, crosswalks, construction sites, accident sites, traffic restrictions, etc. In addition, the objects include obstacles that may affect the driving of the vehicle, such as cars (other vehicles) other than the vehicle, two-wheeled automatic vehicles (motorcycles), bicycles, pedestrians, etc.

[0024] The driving assistance device 14 acquires the detection results of the camera device 11 at a predetermined time interval as needed. The predetermined time interval can be set to an appropriate value according to the processing capability of the driving assistance device 14. In addition, the driving assistance device 14 can also integrate or synthesize the detection results of multiple cameras 11 and a distance measuring device (not shown) to supplement the missing information of the detected object.

[0025] The vehicle state detection device 12 is a device for detecting the driving state of the vehicle, and can include: a speed sensor, an acceleration sensor, a yaw rate sensor (such as a gyro sensor), a steering angle sensor, an inertial measurement unit, etc. These devices are not particularly limited, and known devices can be used. In addition, the configuration and number of these devices can be appropriately set within the range that the driving state of the vehicle can be appropriately detected. The detection results of each device are obtained by the driving assistance device 14 at a specified time interval as needed.

[0026] The steering control device 13 is an on-board computer for electronically controlling the steering device, such as an electronic control unit (ECU). The information required for the steering control device 13 to perform steering control, such as the vehicle's driving speed, acceleration, steering angle (rotation angle of the steering wheel) and posture, is obtained from the vehicle state detection device 12. As a steering device, for example, a steering gear actuator (electric motor) mounted on the column shaft of the steering gear that steers the steering wheel according to the steering angle can be listed. In addition, it can also be a steering gear actuator mounted on the steering rack or pinion of the mechanism for steering the steering wheel. Furthermore, as a wire control steering method that mechanically separates the mechanism for steering the steering wheel from the steering wheel, it is also possible to have both a steering gear actuator mounted on the steering rack or pinion of the mechanism for steering the steering wheel and a steering gear actuator mounted on the column shaft of the steering gear.

[0027] The driving assistance device 14 is a device that controls the driving of the vehicle by controlling the devices constituting the driving assistance system 1 and making them cooperate, and drives the vehicle to the set destination through autonomous driving control. In addition, the driving assistance device 14 is also a device that monitors the driving state of the vehicle when the driver performs steering operations, and performs steering control to suppress the lane deviation of the vehicle. Steering operation refers to, for example, the driver turning the steering wheel. The driving state of the vehicle refers to the parameters detected by the vehicle state detection device 12, and examples thereof include: the vehicle's driving speed, acceleration, lateral speed, lateral acceleration, yaw rate (yaw rate), steering angle, etc.

[0028] Lane deviation refers to a situation where a vehicle crosses the boundary of a lane, and part or all of the vehicle body is included outside the lane when viewed from above. For example, when a vehicle is traveling on a lane demarcated by white lines or other boundary lines, if it crosses the boundary line and enters an adjacent lane of the lane, it is determined that the vehicle has deviated from the lane. Lane demarcation boundaries are not limited to white lines or other boundary lines, but can also be boundary lines between a drivable area and a non-drivable area. For example, guardrails, curbstones on shoulders, central dividers, and dividing lines between paved roads and unpaved roads (such as gravel roads) are also included in lane demarcation boundaries.

[0029] The driving assistance device 14 is, for example, a computer, and includes a CPU (Central Processing Unit) as a processor, a ROM (Read Only Memory) storing programs, and a RAM (Random Access Memory) functioning as an accessible storage device. The CPU is an operating circuit for executing the programs stored in the ROM to realize driving state monitoring and steering control.

[0030] In addition, regarding the devices not shown in the figure, the distance measuring device is a device for calculating the relative distance and relative speed between the vehicle and the object, such as a laser radar, a millimeter wave radar (LRF, etc.), a LiDAR (light detection and ranging) unit, an ultrasonic radar, and other radar devices or sonar. The map information is particularly high-precision map information, including road information, facility information, and their attribute information for generating a driving route, controlling driving actions, etc. The vehicle position detection device is a positioning system for detecting the current position of the vehicle, such as GPS (Global Positioning System). The navigation device is a device that calculates the driving route from the current position of the vehicle detected by the vehicle position detection device to the destination set by the occupant with reference to the map information. The speed control device is a device that generates a signal for controlling the drive device based on the control signal input from the driving assistance device 14 and sends the signal to the drive device, thereby autonomously controlling the driving speed of the vehicle. The display device is, for example, a liquid crystal display, and may also be equipped with an input device and a speaker.

[0031] (Functions of each functional module)

[0032] The driving assistance device 14 has a monitoring function for monitoring the driving state of the vehicle and a steering control function for performing steering control in addition to the driving assistance function for driving the vehicle by autonomous driving control. These functions are realized by causing the CPU of the driving assistance device 14 to execute a program stored in the ROM. Figure 1 In the example above, for convenience, the functional modules that implement each function are extracted and represented. Figure 1 The functions of the functional blocks of the auxiliary unit 2, the identification unit 21, the acquisition unit 22, the setting unit 23, and the control unit 24 shown in the figure will be described.

[0033] The support unit 2 has a function of acquiring information from each device constituting the driving support system 1 , processing the acquired information, and outputting instructions to each device to cause the devices constituting the driving support system 1 to cooperate and execute autonomous driving control. Figure 2 It is a plan view showing an example of a driving scene in which the driving assistance device 14 executes autonomous driving control by the driving assistance function, monitoring by the monitoring function, and steering control by the steering control function.

[0034] Figure 2The driving scene shown in the left figure is a driving scene in which the vehicle V travels from the current position P1 to the position P2 along the driving trajectory T on the lane L defined by the boundary line B1 on the left side of the traveling direction of the vehicle V and the boundary line B2 on the right side of the traveling direction. In this driving scene, the normal autonomous steering control based on the assistance unit 2 is performed, and the steering wheel of the vehicle V is directed to the left by the steering actuator, so that the vehicle V turns to the left. In this case, the driving assistance device 14 performs the autonomous steering control of this embodiment through the steering control function.

[0035] In addition, the autonomous steering control refers to autonomously controlling the steering of the vehicle V using the driving assistance device 14, for example, controlling the rotation of the steering wheel using the steering actuator of the vehicle V, and controlling the rotation of the steering wheel using the steering actuator attached to the steering rack or pinion of the mechanism for rotating the steering wheel. In addition, the autonomous steering control of the present embodiment includes lane departure suppression control for suppressing the vehicle V from deviating from the lane L in which it is traveling. When it is determined that the vehicle V deviates from the lane L during the driving state monitoring, the lane departure suppression control is started, and the steering control for suppressing the vehicle V from deviating from the lane L is executed by the steering control function.

[0036] In a steering system in which a steering wheel and a steering wheel are mechanically connected via a shaft or the like, when the vehicle V turns, a force resisting the vehicle's turning movement is generated in the steering system. Specifically, when the vehicle V rotates the steering wheel in order to turn, a force resisting the change in the movement of the steering wheel is generated (i.e., a resistance that causes the steering wheel and the steering wheel connected to the steering wheel to rotate in opposite directions). In addition, in a steer-by-wire steering system in which the mechanism for turning the steering wheel is not mechanically connected to the steering wheel, when the steering wheel is rotated according to the steering angle, a force resisting the rotation of the steering wheel is generated. Figure 2 In the driving scenario shown in the left figure, when the vehicle V is turned by autonomous steering control using a steering actuator, the resistance is detected as the steering torque that rotates the steering wheel. Figure 3 Explain the relationship between this resistance and the steering torque.

[0037] Figure 3 1 is a time chart showing an example of the relationship between the steering angle and the steering torque when the vehicle V is turned by the autonomous steering control. Figure 3 The upper diagram is a diagram showing the steering angle of the vehicle V (that is, the rotation angle of the steering wheel) rotated by the steering actuator. Figure 3 The lower graph is a graph showing the steering torque detected by the torque sensor. The horizontal axis of both graphs represents time, and the time of the upper graph corresponds to the time of the lower graph. Figure 3In the timing chart shown, when the steered wheel is rotated in the right direction, the steering angle and the steering torque take positive values, and when the steered wheel is rotated in the left direction, the steering angle and the steering torque take negative values.

[0038] exist Figure 3 In the example shown, Figure 3 As shown in the figure on the upper side, from the time when the steering wheel starts to rotate to the time t1, the steering wheel is rotated to the right at a certain angular velocity, from the time t1 to the time t2, the steering wheel is rotated to the left at a certain angular velocity, and from the time t2 to the time t3, the steering wheel is rotated to the right at a certain angular velocity. In this case, even if the driver does not operate the steering wheel, Figure 3 As shown in the lower figure, in the torque sensor, the left steering torque is detected from the start of the steering wheel rotation to time t1, the right steering torque is detected from time t1 to time t2, and the left steering torque is detected from time t2 to time t3.

[0039] return Figure 2 ,exist Figure 2 In the driving scene shown in the left figure, it is assumed that when the vehicle V turns the steering wheel to the left in order to travel along the driving trajectory T (that is, when the steering wheel is facing the left side of the traveling direction), Figure 2 The graph on the right shows the steering torque. Figure 2 The graph shown on the right is a graph showing the steering torque detected by the torque sensor, with the center origin as a reference, and when the steering wheel is turned clockwise, positive values ​​are taken, and when it is turned counterclockwise, negative values ​​are taken.

[0040] In this case, if the left threshold value when the steering wheel is turned to the left and the right threshold value when the steering wheel is turned to the right are set to the same value as the threshold value for releasing the autonomous steering control of the vehicle V, the magnitude of the steering torque detected will exceed Figure 2 The right threshold value (comparative example) shown in the right graph is large enough that the autonomous steering control may be erroneously released even if the driver does not operate the steering wheel.

[0041] Therefore, in the present invention, when the steering wheel rotates in the left direction (that is, when the steering direction of the steering wheel is the left direction), the right threshold value is set to a value larger than the left threshold value, and conversely, when the steering wheel rotates in the right direction (that is, when the steering direction of the steering wheel is the right direction), the left threshold value is set to a value larger than the right threshold value. In addition, when the rotation direction is represented by the positive and negative of the rotation angle, when the steering wheel rotates in the left direction, the absolute value of the right threshold value is set to a value larger than the absolute value of the left threshold value, and conversely, when the steering wheel rotates in the right direction, the absolute value of the left threshold value is set to a value larger than the absolute value of the right threshold value.

[0042] The autonomous steering control of this embodiment is described in detail below. In addition, in the following description, except for the cases where it is specifically stated, the positive and negative values ​​of the thresholds are not used to indicate the rotation direction of the steering wheel and the steering wheel, and the right threshold and the left threshold are both taken as positive values. In addition, the steering wheel is also called the steering wheel.

[0043] The recognition unit 21 has a function of recognizing the driving environment around the vehicle V. The driving assistance device 14 recognizes the driving environment around the vehicle V using the camera device 11 through the function of the recognition unit 21. The driving environment is information used to determine whether the vehicle V can maintain the current driving state and whether it is necessary to change the driving state, for example, including information such as the type and position of the object, the type and position of the obstacle when there is an obstacle, and the road condition. The driving assistance device 14 performs appropriate processing such as pattern matching on the detection result of the camera device 11 to recognize the driving environment.

[0044] exist Figure 2 In the driving scene shown in the left figure, the driving assistance device 14 performs edge extraction processing on the detection result of the camera device 11 to recognize the boundary lines B1 and B2.

[0045] The acquisition unit 22 has a function of acquiring the steering direction of the steered wheels of the vehicle V. The driving assistance device 14 uses the function of the acquisition unit 22 to acquire the rotation direction of the steered wheels based on the detection results of the camera 11, the yaw rate sensor, the steering angle sensor, and the like.

[0046] exist Figure 2 In the driving scene shown in the left figure, the driving assistance device 14 recognizes that the rotation direction of the steered wheel is left (ie, the steering direction of the steered wheel is left) because the yaw rate detected by the yaw rate sensor is a negative value.

[0047] The setting unit 23 has a function of setting, as thresholds for releasing the autonomous steering control of the vehicle V, a left threshold for releasing the autonomous steering control when the steering wheel is turned to the left direction, and a right threshold for releasing the autonomous steering control when the steering wheel is turned to the right direction. The driving assistance device 14 of this embodiment sets the right threshold to be larger than the left threshold through the function of the setting unit 23 when the steering direction acquired by the function of the acquisition unit 22 is the left direction. On the other hand, when the acquired steering direction is the right direction, the left threshold is set to be larger than the right threshold. For example, when the rotation direction is the left direction, the driving assistance device 14 sets the right threshold to a value obtained by multiplying the left threshold by a predetermined coefficient (for example, 1.5 to 3), and when the rotation direction is the right direction, the left threshold is set to a value obtained by adding a predetermined value (for example, 0.5 to 2 [Nm]) to the right threshold.

[0048] exist Figure 2In the driving scene shown in the left figure, the driving assistance device 14 sets the right threshold value to a value twice the left threshold value, for example, because the rotation direction of the steering wheel is left (that is, the steering direction of the steering wheel is left).

[0049] The control unit 24 has a function of releasing the autonomous steering control when the absolute value of the torque input to the steering wheel exceeds the left threshold value or the right threshold value. The driving assistance device 14 determines whether the absolute value of the torque input to the steering wheel exceeds the left threshold value or the right threshold value through the function of the control unit 24, and continues the autonomous steering control when the absolute value of the torque does not exceed the left threshold value or the right threshold value. On the other hand, when the absolute value of the torque exceeds the left threshold value or the right threshold value, the autonomous steering control is released and switched to manual driving by the driver.

[0050] The driving assistance device 14 may also operate the steering gear actuator via the steering control device 13 to rotate the steering wheel to the left or right to adjust the steering angle. In the case of a steer-by-wire system in which the mechanism for steering the steering wheel is mechanically separated from the steering wheel, it is possible to adjust one or both of the steering angle of the steering gear actuator mounted on the steering rack or pinion of the mechanism for steering the steering wheel and the steering angle of the steering gear actuator mounted on the column shaft of the steering gear. In addition, the release of the autonomous steering control refers to the termination of the execution of the autonomous steering control based on the driving assistance device 14. In addition, manual driving refers to the driving assistance device 14 not performing autonomous driving control of driving actions, but controlling the driving of the vehicle through the operation of the driver.

[0051] exist Figure 2 In the driving scenario shown in the left figure, the steering torque detected by the torque sensor does not exceed the right threshold value, so the driving assistance device 14 continues the autonomous steering control and drives from the current position P1 to the position P2.

[0052] The driving assistance device 14 of the present embodiment may also determine whether the vehicle V is turning by the autonomous steering control through the function of the acquisition unit 22, and acquire the steering direction of the steering wheel when it is determined that the vehicle V is turning by the autonomous steering control. In this case, when the steering direction is the left direction, the right threshold is set to be larger than the left threshold, and when the steering direction is the right direction, the left threshold is set to be larger than the right threshold. For example, the driving assistance device 14 acquires the steering direction of the steering wheel, and sets the left threshold and the right threshold according to the steering direction before the autonomous steering control starts. Then, it is determined whether the turning of the vehicle V is completed, and the left threshold and the right threshold are maintained until it is determined that the turning is completed. In this way, it is possible to suppress the switching of thresholds during the turning of the vehicle V, and avoid releasing the autonomous steering control at a time when the driver does not want.

[0053] The autonomous steering control of the present embodiment may be performed in combination with monitoring by the monitoring function of the driving assistance device 14. For example, when the vehicle V is traveling by the steering operation of the driver, the driving assistance device 14 may determine whether the vehicle V has deviated from the lane L in which it is traveling by the function of the control unit 24, and when it is determined that the vehicle V has deviated from the lane L in which it is traveling, the steering deviation suppression control for suppressing the vehicle V from deviating from the lane L instead of the steering operation of the driver is started. In contrast, when it is determined that the vehicle V has not deviated from the lane L in which it is traveling, the lane departure suppression control is not started, and the steering operation of the driver is continued.

[0054] When determining whether the vehicle V has deviated from the lane L, the driving assistance device 14 acquires the traveling direction of the vehicle V, and when the vehicle V continues to travel in the traveling direction, determines whether the vehicle V has crossed the boundary defining the lane L and deviated from the lane L. The traveling direction of the vehicle V is identified based on the yaw rate acquired from the yaw rate sensor, the steering angle acquired from the steering angle sensor, and the like.

[0055] As an example of a method for determining whether the vehicle V has deviated, the driving assistance device 14 detects the boundary of the lane L in which the vehicle V is traveling, and recognizes the positional relationship between the boundary and the vehicle V (for example, the distance between the vehicle V and the boundary). Then, when the vehicle V is traveling while maintaining the yaw angle relative to the boundary, it is determined whether it has crossed the boundary that demarcates the lane L. For example, the driving assistance device 14 calculates the lane yaw angle (the relative lane yaw angle) which is the angle formed by the traveling direction of the vehicle V and the tangent direction of the lane L at the driving position of the vehicle V on the lane L. In addition, the driving assistance device 14 calculates the distance in the width direction between the vehicle V and the boundary line B1. Then, the deviation of the vehicle V is predicted based on the lane yaw angle and the distance in the width direction. As an example, the lane yaw angle is an angle within the range in which the vehicle V can travel along the lane L. When the distance between the vehicle V and the boundary line B1 becomes longer (that is, the vehicle V is separated from the boundary line B1), it is predicted that the vehicle V will not deviate from the lane L. In contrast, when the lane deviation angle of the vehicle V is greater than or less than the range within which the vehicle V can travel along the lane L (i.e., when the lane deviation angle required for the steering angle is too large or too small), when the distance between the vehicle V and the boundary line B1 is shortened (i.e., when the vehicle V is close to the boundary line B1), etc., it is predicted that the vehicle deviates from the lane L. In addition, the tangent line to the boundary line B1 is, for example, the tangent line at the point on the boundary line B1 closest to the body of the vehicle V.

[0056] The driving assistance device 14 of the present embodiment acquires the deviation direction of the vehicle V from the lane L when the lane departure suppression control is started instead of the driver's steering operation. The deviation direction of the vehicle V refers to the direction in which the vehicle V is heading when the vehicle V deviates from the lane L in which it is traveling, and indicates whether the vehicle V deviates to the right or the left relative to the traveling direction. That is, when it is predicted that the vehicle V deviates from the lane L in which it is traveling, the deviation direction indicates which of the boundaries defining the lane L is crossed, the boundary on the right side of the traveling direction and the boundary on the left side. When the deviation direction is the left direction, the vehicle V deviates from the lane L by crossing the boundary on the left side of the traveling direction, and when the deviation direction is the right direction, the vehicle V deviates from the lane L by crossing the boundary on the right side of the traveling direction.

[0057] The driving assistance device 14 acquires the deviation direction of the vehicle V from the lane L based on the information of the traveling direction of the vehicle V used when predicting that the vehicle V deviates from the lane L. For example, when it is predicted that the vehicle V deviates from the lane L, if the traveling direction of the vehicle V is to the left front or to the left side of the vehicle V, the deviation direction is the left direction, and if the traveling direction of the vehicle V is to the right front or to the right side of the vehicle V, the deviation direction is the right direction.

[0058] In addition, when the direction in which the vehicle V deviates from the lane L is the left direction relative to the traveling direction of the vehicle V, the driving assistance device 14 sets the left threshold value to be larger than the right threshold value. This is to rotate the steering wheel to the right direction when the vehicle V deviates to the left direction relative to the traveling direction. On the other hand, when the direction in which the vehicle V deviates from the lane L is the right direction relative to the traveling direction of the vehicle V, the right threshold value is set to be larger than the left threshold value. This is to rotate the steering wheel to the left direction when the vehicle V deviates to the right direction relative to the traveling direction.

[0059] For example, in Figure 2 In the driving scenario shown in the left figure, when it is determined that the driver's steering wheel operation is delayed and the vehicle V deviates from the lane L to the right in the traveling direction, the driving assistance device 14 recognizes that the vehicle V deviates from the traveling direction of the vehicle V to the right with respect to the traveling direction, and sets the right threshold value to a value 1.5 times the left threshold value. In this way, by setting the values ​​of the right threshold value and the left threshold value according to the direction in which the vehicle V deviates, it is possible to set a threshold value for releasing the autonomous steering control (lane departure suppression control) without acquiring the rotation direction of the steering wheel.

[0060] In addition, the process of determining whether the vehicle V has deviated from the lane L, the process of starting the lane departure suppression control to suppress the vehicle V from deviating from the lane L, and the process of obtaining the deviation direction of the vehicle V from the lane L are not essential components of the present invention and may be provided as needed. In addition, the process of setting the right threshold value and the left threshold value according to the deviation direction is not essential to the present invention and may be provided as needed.

[0061] In addition, the faster the rotation speed of the steering wheel, the greater the difference between the right threshold and the left threshold may be set by the driving assistance device 14. This is because the greater the ratio of the steering angle change, the greater the resistance generated in the steering system. The process of setting the right threshold and the left threshold according to the rotation speed of the steering wheel is not a necessary configuration of the present invention, and can be added or omitted as needed.

[0062] (Processing in driver assistance systems)

[0063] Reference Figure 4-5 , describing the order in which the driving assistance device 14 processes information. Figure 4 FIG. 1 is an example of a flowchart showing information processing executed in the driving assistance system 1 according to the present embodiment. Figure 4 The driving scenario of the processing is based on a driving scenario in which the vehicle V is traveling in the lane L by autonomous steering control. The processing described below is executed by the CPU as a processor of the driving assistance device 14 at predetermined time intervals.

[0064] First, in step S1, the function of the acquisition unit 22 determines whether the vehicle V is turning by autonomous steering control. If it is determined that the vehicle V is not turning by autonomous steering control, the process proceeds to step S2, and the normal autonomous steering control is performed by the function of the auxiliary unit 2, and the process proceeds to step S1. On the other hand, if it is determined that the vehicle V is turning by autonomous steering control, the process proceeds to step S3, and the function of the setting unit 23 sets the right threshold and the left threshold as thresholds for releasing the autonomous steering control. In the next step S4, the steering direction of the steering wheel of the vehicle V is acquired by the function of the acquisition unit 22, and in step S5, the function of the control unit 24 determines whether the steering direction is the left direction. If the steering direction is the left direction, the process proceeds to step S6, and the right threshold is set to be larger than the left threshold. If the steering direction is the right direction, the process proceeds to step S7, and the left threshold is set to be larger than the right threshold.

[0065] In step S8, it is determined whether the absolute value of the input steering torque exceeds the left threshold value or the right threshold value. If it is determined that the absolute value of the input steering torque does not exceed the left threshold value or the right threshold value, the process proceeds to step S9 to continue the autonomous steering control. In the following step S10, it is determined whether the steering of the vehicle V is completed. If it is determined that the steering of the vehicle V is not completed, the process proceeds to step S8. On the other hand, if it is determined that the steering of the vehicle V is completed, the process proceeds to step S11 to determine whether the vehicle V has arrived at the destination. If it is determined that the vehicle V has arrived at the destination, the execution of the program is terminated and the system is switched to manual driving by the driver. On the other hand, if it is determined that the vehicle V has not arrived at the destination, the process proceeds to step S1.

[0066] On the other hand, if it is determined in step S8 that the absolute value of the input steering torque exceeds the left threshold or the right threshold, the process proceeds to step S12, where the autonomous steering control is released and the driver's manual driving is switched. In addition, steps S1, S2, S10 and S11 are not essential steps of the present invention and may be added or omitted as needed.

[0067] then, Figure 5 FIG. 1 is another example of a flowchart showing information processing executed in the driving assistance system 1 according to the present embodiment. Figure 5 The driving scene of the processing is a driving scene in which the vehicle V is driven by the driver's steering operation while the driving state of the vehicle V is monitored by the monitoring function of the driving assistance device 14. The processing described below is executed by the CPU as a processor of the driving assistance device 14 at predetermined time intervals.

[0068] First, in step S21, the traveling direction of the vehicle V is acquired by the function of the acquisition unit 22, and in the following step S22, the function of the control unit 24 determines whether the vehicle V has deviated from the lane L. If it is determined in step S22 that the vehicle V has not deviated from the lane L, the process proceeds to step S21 to continue monitoring the traveling state. On the other hand, if it is determined that the vehicle V has deviated from the lane L, the process proceeds to step S23.

[0069] In step S23, lane departure suppression control is started by the function of the control unit 24. In step S24, the right threshold and left threshold for releasing the autonomous steering control (lane departure suppression control) are set by the function of the setting unit 23, and in the following step S25, the direction in which the vehicle V deviates is acquired by the function of the acquisition unit 22. In step S26, it is determined by the function of the control unit 24 whether the direction in which the vehicle V deviates is to the left of the traveling direction. In the case where the deviation direction is to the left of the traveling direction, the process proceeds to step S27, and the left threshold is set to be larger than the right threshold. In contrast, in the case where the deviation direction of the vehicle V is to the right of the traveling direction, the process proceeds to step S28, and the right threshold is set to be larger than the left threshold.

[0070] In step S29, in order to prevent the vehicle V from deviating from the lane L, the steering direction of the steering wheel is controlled using the steering actuator. In the following step S30, it is determined whether the absolute value of the input steering torque exceeds the left threshold value or the right threshold value. If it is determined that the absolute value of the input steering torque does not exceed the left threshold value or the right threshold value, the process proceeds to step S31 to continue the autonomous steering control (lane departure suppression control). In the following step S32, it is determined whether the vehicle V deviates from the lane L. If it is determined that the vehicle V deviates from the lane L, the process proceeds to step S29. In contrast, if it is determined that the vehicle V does not deviate from the lane L, the process proceeds to step S33, the lane departure suppression control is terminated, and the monitoring of the driving state is continued.

[0071] On the other hand, if it is determined in step S30 that the absolute value of the input steering torque exceeds the left threshold or the right threshold, the process proceeds to step S34 to release the autonomous steering control (lane departure prevention control). After that, the program execution is terminated, the driving state is continued to be monitored, and the driving is switched to the driving based on the driver's steering operation.

[0072] (Embodiment of the present invention)

[0073] As described above, according to the present embodiment, a driving assistance method is provided, in which the processor obtains the steering direction of the steering wheel of the vehicle as a threshold for releasing the autonomous steering control of the vehicle V, sets a left threshold when the steering wheel is rotated in the left direction and a right threshold when the steering wheel is rotated in the right direction, releases the autonomous steering control when the absolute value of the torque input to the steering wheel exceeds the left threshold or the right threshold, and makes the right threshold greater than the left threshold when the steering direction is the left direction, and makes the left threshold greater than the right threshold when the steering direction is the right direction. Thus, it is possible to suppress the autonomous steering control from being released erroneously without depending on the steering operation of the driver, and smoothly switch to the manual driving of the driver.

[0074] In addition, according to the driving assistance method of the present embodiment, the processor determines whether the vehicle V is turning by the autonomous steering control, and when it is determined that the vehicle V is turning by the autonomous steering control, the steering direction is acquired, and when the steering direction is the left direction, the right threshold is set to be larger than the left threshold, and when the steering direction is the right direction, the left threshold is set to be larger than the right threshold. Thus, frequent switching of the steering direction during the autonomous steering control can be suppressed, and the autonomous steering control can be prevented from being released at a time when the driver does not want.

[0075] In addition, according to the driving assistance method of the present embodiment, the processor determines whether the vehicle V traveling by the driver's steering operation deviates from the lane L in which the vehicle V is traveling, and when it is determined that the vehicle V deviates from the lane L, the processor obtains the direction in which the vehicle V deviates from the lane L, and when the vehicle deviates to the left relative to the traveling direction, the left threshold is set to be larger than the right threshold, and when the vehicle deviates to the right relative to the traveling direction, the processor sets the right threshold to be larger than the left threshold. Thus, the threshold for releasing the autonomous steering control can be set without obtaining the rotation direction of the steering wheel, and the processing in the driving assistance device 14 can be performed simply.

[0076] In addition, according to the driving assistance method of this embodiment, the processor sets the difference between the right threshold and the left threshold to be larger as the rotation speed of the steering wheel is faster. Thus, the threshold can be set according to the ratio of the change in the steering angle.

[0077] In addition, according to the present embodiment, there is provided a driving assistance device 14, comprising: an acquisition unit 22 that acquires the steering direction of the steering wheel of the vehicle V; a setting unit 23 that sets a left threshold value when the steering wheel is rotated in the left direction and a right threshold value when the steering wheel is rotated in the right direction as threshold values ​​for releasing the autonomous steering control of the vehicle V; and a control unit 24 that releases the autonomous steering control when the absolute value of the torque input to the steering wheel exceeds the left threshold value or the right threshold value, and when the steering direction is the left direction, the right threshold value is larger than the left threshold value, and when the steering direction is the right direction, the left threshold value is larger than the right threshold value. Thus, it is possible to suppress the autonomous steering control from being released erroneously without depending on the steering operation of the driver, and smoothly switch to the manual driving of the driver.

[0078] Explanation of symbols

[0079] 1: Driving assistance system

[0080] 11: Camera device, 12: Vehicle status detection device, 13: Steering control device, 14: Driving assistance device

[0081] 2: Auxiliary Department

[0082] 21: Identification unit, 22: Acquisition unit, 23: Setting unit, 24: Control unit

[0083] B1, B2: boundary line, L: lane, P1: current position, P2: position, T: driving trajectory, V: vehicle.

Claims

1. A driving assistance method, executed by a processor, wherein: The processor performs the following processing: Get the steering direction of the vehicle's steering wheel. A left threshold value when the steering wheel is rotated to the left and a right threshold value when the steering wheel is rotated to the right are set as threshold values ​​for releasing the autonomous steering control of the vehicle, When the absolute value of the torque input to the steering wheel exceeds the left threshold value or the right threshold value, releasing the autonomous steering control; When the steering direction is the left direction, the right threshold is greater than the left threshold. When the steering direction is the right direction, the left threshold is larger than the right threshold.

2. The driving assistance method according to claim 1, wherein: The processor performs the following processing: determining whether the vehicle is turning by the autonomous steering control, When it is determined that the vehicle is turning by the autonomous steering control, acquiring the turning direction, When the steering direction is the left direction, the right threshold is set to be larger than the left threshold. When the steering direction is the right direction, the left threshold is set larger than the right threshold.

3. The driving assistance method according to claim 1 or 2, wherein: The processor performs the following processing: determining whether the vehicle driven by a driver's steering operation has deviated from a lane in which it is traveling, When it is determined that the vehicle has deviated from the lane, obtaining a direction in which the vehicle has deviated from the lane, When the vehicle deviates to the left with respect to the traveling direction, the left threshold is set to be larger than the right threshold, When the vehicle deviates to the right with respect to the traveling direction, the right threshold is set to be larger than the left threshold.

4. The driving assistance method according to claim 1 or 2, wherein: The processor sets the difference between the right threshold and the left threshold to be larger as the rotation speed of the steering wheel is faster.

5. A driving assistance device comprising: an acquisition unit, which acquires a steering direction of a steering wheel of the vehicle; a setting unit that sets a left threshold value when the steering wheel is rotated in the left direction and a right threshold value when the steering wheel is rotated in the right direction as threshold values ​​for releasing the autonomous steering control of the vehicle; a control unit that releases the autonomous steering control when the absolute value of the torque input to the steering wheel exceeds the left threshold value or the right threshold value, When the steering direction is the left direction, the right threshold is greater than the left threshold. When the steering direction is the right direction, the left threshold is larger than the right threshold.

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