JP7298458B2 - Steering control device and steering control method - Google Patents

Description

The present invention relates to a steering control device and a steering control method for controlling steering of a vehicle.

Conventionally, the steering of the own vehicle is controlled so that the own vehicle follows a preceding vehicle traveling in front of the own vehicle. For example, Patent Literature 1 discloses performing steering control of the own vehicle based on the position information of the preceding vehicle.

JP-A-2005-332192

When the own vehicle is a large vehicle such as a truck, it may travel following a small vehicle such as a passenger car. Larger vehicles have a longer rear overhang than smaller vehicles. Therefore, when the own vehicle follows the small vehicle, the rear end portion of the own vehicle on the opposite side of the movement direction of the own vehicle may run off the lane.

Therefore, the present invention has been made in view of these points, and an object of the present invention is to provide a technique for suppressing the rear end of a vehicle from running off the lane.

In a first aspect of the present invention, a distance specifying unit that specifies a distance from a roadway outside line in a direction opposite to a moving direction of the vehicle in a lane width direction of the lane in which the vehicle travels to a predetermined position of the vehicle; a limit angle specifying unit that specifies, based on the distance specified by the distance specifying unit, a limit angle for preventing the rear end portion of the vehicle in the direction opposite to the moving direction of the vehicle from protruding from the outside line of the roadway; an azimuth angle specifying unit that specifies an azimuth angle of the vehicle based on a direction perpendicular to the width direction; and the azimuth angle specified by the azimuth angle specifying unit that is higher than the limit angle specified by the limit angle specifying unit. a steering angle setting unit that sets the steering angle of the vehicle so that the steering angle is small; and a steering control unit that performs steering control of the vehicle so that the steering angle is set by the steering angle setting unit. Provide equipment.

For example, when the steering angle setting unit sets a steering angle that reduces the relative distance between the vehicle ahead of the vehicle and the vehicle in the lane width direction, and determines that the azimuth angle is equal to or greater than the limit angle. , the absolute value of the set steering angle is reduced.

For example, the azimuth angle specifying unit determines the steering angle or yaw rate of the vehicle from the time when the outside line of the roadway can no longer be detected or when control for the vehicle to follow the preceding vehicle of the vehicle is started to the present. Identify the azimuth angle.

For example, the steering control device further includes a curve detection unit that detects whether the vehicle is traveling on a curve, and the steering angle setting unit detects that the curve detection unit is traveling on a curve. In this case, the steering angle is not set such that the azimuth angle is smaller than the limit angle.

In a second aspect of the present invention, a processor mounted on a vehicle executes a step from a roadway line in a lane width direction of a lane in which the vehicle travels to a predetermined position of the vehicle from a roadway outside line in a direction opposite to a moving direction of the vehicle. determining, based on the distance, a limit angle for preventing the rear end of the vehicle in the direction opposite to the moving direction of the vehicle from protruding from the roadway outside line; and determining, based on the distance, the lane width determining an azimuth angle of the vehicle with respect to a direction perpendicular to the direction; setting a steering angle of the vehicle so that the azimuth angle is smaller than the limit angle; and a step of performing steering control of the vehicle so that the steering control method is provided.

ADVANTAGE OF THE INVENTION According to this invention, it is effective in the ability to suppress the rear-end part of a vehicle sticking out from a lane.

It is a figure for demonstrating the outline|summary of a steering control method. It is a figure which shows typically the internal structure of the vehicle which concerns on this embodiment. FIG. 5 is a diagram for explaining how to reduce the absolute value of the set steering angle; 4 is a flow chart showing an example of the flow of processing in the steering control device according to the present embodiment;

[Outline of steering control method]
For example, when the vehicle is traveling in the auto-cruise mode, the steering control device according to the present embodiment controls the steering of the vehicle to follow the preceding vehicle traveling ahead in the traveling direction of the vehicle. It is a computer to run. The steering control device is assumed to be mounted on large vehicles such as buses and trucks, but may be mounted on small vehicles such as passenger cars.

First, with reference to FIG. 1, an overview of the steering control method executed by the steering control device according to this embodiment will be described. FIG. 1 is a diagram for explaining an outline of a steering control method. The lane width direction Y in FIG. 1 is the lane width direction of the lane in which the vehicle V travels. As for the lane width direction Y, the direction toward the roadway outside line on the left side of the lane is positive. The direction X is a direction perpendicular to the lane width direction Y (a direction orthogonal to the lane width direction Y on a plane parallel to the road surface).

The traveling direction F is the traveling direction of the vehicle V with the direction X as a reference. The azimuth angle β is an angle indicating the traveling direction of the vehicle V with the direction X as a reference. A vehicle V shown in FIG. 1 is moving in a direction toward the left side of the roadway (positive direction in the lane width direction Y). Then, when the absolute value of the steering angle of the vehicle V becomes larger than the current value, the rear end portion Q on the right side of the vehicle V crosses the outside line A of the roadway.

The limit angle θ is the angle formed between the roadway outside line A and the side surface S of the vehicle V when the rear end portion Q of the vehicle V reaches the roadway outside line A. When the rear end Q of the vehicle V reaches the roadway outside line A, the limit angle θ becomes equal to the azimuth angle β of the vehicle V. That is, the rear end portion Q crosses the roadway outside line A when the azimuth angle β is larger than the limit angle θ, and does not cross the roadway outside line A when the azimuth angle β is smaller than the limit angle θ.

Therefore, the steering control device according to the present embodiment specifies the limit angle θ when the rear end portion Q of the vehicle V reaches the roadway outer line A at the current position, and the azimuth angle β The vehicle V is steered and controlled so that . By doing so, the steering control device can prevent the rear end portion Q of the vehicle V from running off the lane.

[Structure of Steering Control Device]
The configuration of a steering control device 1 according to this embodiment will be described below with reference to FIGS. 1 and 2. FIG. FIG. 2 is a diagram schematically showing the internal configuration of the vehicle V according to this embodiment. A vehicle V includes a steering control device 1 , an imaging device 2 , various sensors 3 , and a motor 4 .

The imaging device 2 captures an image of the forward direction of the vehicle V, including the lane in which the vehicle V travels, at predetermined time intervals (for example, 10 milliseconds). The imaging device 2 outputs the captured image to the steering control device 1 . In addition, in this embodiment, although the vehicle V shall be equipped with the imaging device 2, it is not restricted to this. The vehicle V may include LiDAR (Light Detection and Ranging) instead of the imaging device 2, or may include both the imaging device 2 and LiDAR.

The various sensors 3 include sensors that detect the traveling conditions of the vehicle V. As shown in FIG. The sensor that detects the running condition of the vehicle V is, for example, a steering angle sensor that detects the steering angle of the vehicle V and a yaw rate sensor that detects the yaw rate. Various sensors 3 may also include a GPS (Global Positioning System) receiver for detecting the position of the vehicle V. FIG. When the GPS receiver is included, the various sensors 3 can detect the position of the vehicle V as the running condition.

The motor 4 is provided on the steering shaft of the vehicle V. As shown in FIG. The motor 4 is rotationally driven under the control of the steering control device 1 to apply torque to the steering shaft and perform steering control.

The steering control device 1 includes a storage section 11 and a control section 12 . The storage unit 11 is, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), or a hard disk. The storage unit 11 stores various programs for causing the control unit 12 to function. The storage unit 11 stores a steering control program that causes the control unit 12 to function as a distance identification unit 121, a limit angle identification unit 122, a steering angle setting unit 124, an azimuth angle identification unit 123, a steering control unit 125, and a curve detection unit 126. Remember.

The control unit 12 is, for example, a CPU (Central Processing Unit). By executing the steering control program stored in the storage unit 11, the control unit 12 executes a distance specifying unit 121, a limit angle specifying unit 122, a steering angle setting unit 124, an azimuth specifying unit 123, a steering control unit 125, and function as a curve detection unit 126 .

The distance specifying unit 121 specifies the distance from the outside line of the lane in which the vehicle V travels to a predetermined position of the vehicle V. As shown in FIG. For example, as shown in FIG. 1, the distance specifying unit 121 specifies the distance L from the roadway outside line A at the current position of the vehicle V to the turning center P of the vehicle V. As shown in FIG. Specifically, the distance specifying unit 121 detects the roadway outside line A included in the captured image captured by the imaging device 2, and specifies the distance L from the detected roadway outside line A to the turning center P of the vehicle V. . When the roadway outside line A cannot be detected, the distance specifying unit 121 specifies the distance from the turning center P to the roadway outside line A based on the roadway outside line A detected before the roadway outside line A cannot be detected. Note that the distance specifying unit 121 can specify the position of the turning center P of the vehicle V in the lane width direction based on the left side roadway line and the right side roadway line included in the captured image.

When the movement direction of the vehicle V is identified, the distance identification unit 121 determines the distance from the roadway outside line A in the direction opposite to the movement direction of the vehicle V in the lane width direction Y of the lane in which the vehicle V travels to the turning center P. Identify L. Further, when the moving direction of the vehicle V cannot be specified, the distance specifying unit 121 determines the distance from the left side roadway line of the vehicle V to the turning center P and the distance from the right side roadway line of the vehicle V to the turning center P. may be specified for each of the distances of .

The azimuth angle specifying unit 123 specifies the azimuth angle β of the vehicle V with respect to the direction X perpendicular to the lane width direction Y as a reference. For example, the azimuth angle identification unit 123 identifies the azimuth angle β based on the steering angle or yaw rate detected by the various sensors 3 . Specifically, the azimuth angle identification unit 123 identifies the azimuth angle β based on the steering angle or yaw rate of the vehicle V from a predetermined time before the present to the present. More specifically, the azimuth angle identification unit 123 integrates the steering angle or yaw rate of the vehicle V from the time when the roadway outside line A can no longer be detected or when the vehicle V starts to follow the preceding vehicle. Determine the azimuth angle β based on the value.

The azimuth angle identification unit 123 identifies the movement direction of the vehicle V in the lane width direction Y. As shown in FIG. For example, the azimuth angle identification unit 123 identifies the movement direction based on the identified azimuth angle β. Specifically, the azimuth angle identification unit 123 identifies the movement direction based on the sign of the steering angle with respect to the direction X perpendicular to the lane width direction Y as a reference. In this embodiment, the steering angle is positive when turning counterclockwise with respect to the direction X, and negative when turning clockwise.

Based on the distance L specified by the distance specifying unit 121, the limit angle specifying unit 122 specifies a limiting angle θ for preventing the rear end Q of the vehicle V from protruding from the outside line A of the roadway. Specifically, the limit angle specifying unit 122 determines the limit angle θ identify. More specifically, the limit angle specifying unit 122 specifies the limit angle θ by subtracting the angle ψ determined based on the distances R and W from the angle φ determined based on the distances L and R.

When the moving direction of the vehicle V in the lane width direction Y can be specified, the limit angle specifying unit 122 sets a limit angle for the rear end portion Q in the direction opposite to the moving direction of the vehicle V not to protrude the roadway outside line A. Identify θ. When the moving direction of the vehicle V in the lane width direction Y cannot be specified, the limit angle specifying unit 122 provides a limit angle for preventing the left rear end of the vehicle V from protruding, and a limit angle for preventing the right rear end of the vehicle V from protruding. Identify each limiting angle for

The steering angle setting unit 124 sets the steering angle of the vehicle V in order to drive the vehicle V in the auto-cruise mode. For example, the steering angle setting unit 124 detects the center position of the lane based on the captured image captured by the imaging device 2, and performs steering control so that the vehicle V travels in the center position of the lane. When the center position of the lane cannot be detected, the steering angle setting unit 124 sets the steering angle such that the preceding vehicle traveling in front of the vehicle V in the traveling direction is followed. Specifically, the steering angle setting unit 124 sets a follow-up steering angle, which is a steering angle that reduces the relative distance between the preceding vehicle of the vehicle V and the vehicle V in the lane width direction Y.

The steering angle setting unit 124 determines whether or not the azimuth angle β specified by the azimuth angle specifying unit 123 is greater than or equal to the limit angle θ specified by the limit angle specifying unit 122 . When the steering angle setting unit 124 determines that the azimuth angle β is equal to or greater than the limit angle θ, the steering angle setting unit 124 resets the steering angle of the vehicle V so that the azimuth angle β becomes smaller than the limit angle θ. Specifically, when determining that the azimuth angle β is greater than or equal to the limit angle θ, the steering angle setting unit 124 reduces the absolute value of the set follow-up steering angle.

FIG. 3 is a diagram for explaining how to reduce the absolute value of the set steering angle. The horizontal axis in FIG. 3 indicates the time, and the vertical axis indicates the magnitude of the absolute value of the set steering angle. The solid line indicates the change over time of the follow-up steering angle D1 set so that the relative distance between the preceding vehicle of the vehicle V and the vehicle V in the lane width direction becomes small. The time T1 in FIG. 3 is the time when the steering angle setting unit 124 determines that the azimuth angle β becomes larger than the limit angle θ.

Steering angle setting unit 124 reduces the absolute value of follow-up steering angle D1 at times after time T1. The dashed line shows the change over time of the steering angle D2 when the absolute value of the follow-up steering angle D1, which is set so that the relative distance in the lane width direction Y between the preceding vehicle of the vehicle V and the vehicle V is small, is reduced. At time T2, it can be confirmed that the steering angle D2 is smaller than the follow-up steering angle D1. Thus, the steering angle setting unit 124 reduces the absolute value of the follow-up steering angle D1 when the azimuth angle β is greater than or equal to the limit angle θ. As a result, the steering control device 1 can perform steering control of the vehicle V so that the azimuth angle β does not exceed the limit angle θ, so that the rear end portion Q can be prevented from running off the roadway outside line A.

When the vehicle V is running in the auto-cruise mode, the steering control unit 125 controls the motor 4 to apply torque to the steering shaft and perform operation control. Specifically, the steering control unit 125 performs steering control of the vehicle V so as to achieve the steering angle set by the steering angle setting unit 124 . By doing so, the steering control unit 125 can control the steering of the vehicle V so that the azimuth angle β does not exceed the limit angle θ, so that the trailing edge Q can be prevented from running off the roadway outside line A.

If the steering control device 1 controls the steering angle of the vehicle V so that the azimuth angle β is smaller than the limit angle θ even when the vehicle V is traveling on the curved portion of the roadway, the vehicle V will move to the outside of the curved portion of the roadway. I run to the outside of the line. Therefore, the steering control device 1 does not control the steering angle of the vehicle V so that the azimuth angle β becomes smaller than the limit angle θ when the vehicle V is traveling on the curved portion of the roadway. Hereinafter, the processing when the vehicle V travels on the curved portion of the roadway will be described.

First, the curve detection unit 126 detects whether the vehicle V is traveling on a curve. For example, the curve detection unit 126 detects whether or not the vehicle V is traveling on a curve based on the relative speed in the lane width direction between the vehicle V and the preceding vehicle that the vehicle V follows. Specifically, when the relative speed in the lane width direction is equal to or less than a predetermined speed and the absolute value of the steering angle of the vehicle V detected by the various sensors 3 is equal to or greater than a predetermined value, the curve detection unit 126 detects that the vehicle V Detects that the vehicle is traveling on a curve.

Further, when the absolute value of the steering angle is equal to or greater than a predetermined value and the relative distance between the preceding vehicle and the vehicle V in the lane width direction does not change, the curve detection unit 126 determines that the vehicle V is traveling on the curve. may be detected. Specifically, curve detection unit 126 detects that vehicle V is traveling on a curve when the relative distance change rate is equal to or less than a predetermined rate. The curve detection unit 126 may detect whether the vehicle V is traveling on a curve based on the position of the vehicle V detected by the various sensors 3 and the map information stored in the storage unit 11. Alternatively, it may be detected whether or not the vehicle is traveling on a curved section by other methods.

The curve detection unit 126 detects the direction in which the curve turns when it is detected that the vehicle V is traveling on the curve. For example, the curve detection unit 126 detects the direction in which the curve bends based on the relative position of the preceding vehicle with respect to the vehicle V. FIG. Note that the curve detection unit 126 may detect the turning direction of the curve on which the vehicle V travels based on the position of the vehicle V and map information.

When the curve detection unit 126 detects that the vehicle is running on a curve, the steering angle setting unit 124 does not set the steering angle such that the azimuth angle β becomes smaller than the limit angle θ. For example, when the steering angle setting unit 124 detects that the vehicle is traveling on a curved line, the azimuth angle β Do not set a steering angle that reduces Specifically, when the curve bends to the left and the sign of the steering angle of the vehicle V is positive, the steering angle setting unit 124 sets the steering angle such that the azimuth angle β is smaller than the limit angle θ. Not set.

When the steering angle setting unit 124 does not set the steering angle, the steering control unit 125 controls the steering of the vehicle V so as to follow the preceding vehicle. By doing so, the steering control unit 125 can prevent the vehicle V from traveling toward the outer side of the roadway line of the curved portion while traveling on the curved portion.

[Flow of processing for performing steering control in the steering control device 1]
Next, the flow of processing in the steering control device 1 will be described. FIG. 4 is a flowchart showing an example of the flow of processing in the steering control device 1 according to this embodiment. The processing according to the flowchart of FIG. 4 is executed when the vehicle V starts controlling to follow the preceding vehicle.

First, at the current position of the vehicle V in the lane width direction, the distance specifying unit 121 determines the distance from the turning center P of the vehicle V to the right side road line A, and the distance from the turning center P to the left side road line A. is specified (step S1). Subsequently, the limit angle specifying unit 122 specifies a limit angle for preventing the right rear end of the vehicle V from protruding and a limit angle for preventing the left rear end of the vehicle V from protruding. (Step S2).

The steering angle setting unit 124 sets a steering angle that reduces the relative distance between the vehicle V and the preceding vehicle in the lane width direction so that the vehicle V follows the preceding vehicle (step S3). The azimuth angle identification unit 123 identifies the moving direction of the vehicle V in the lane width direction and the azimuth angle β of the vehicle V (step S4).

The steering angle setting unit 124 acquires from the limit angle specifying unit 122 the limit angle θ in the direction opposite to the moving direction of the vehicle V in the lane width direction specified by the azimuth angle specifying unit 123 . Then, the steering angle setting unit 124 determines whether or not the absolute value of the azimuth angle β specified by the azimuth angle specifying unit 123 is greater than or equal to the acquired limit angle θ (step S5).

When the steering angle setting unit 124 determines that the absolute value of the azimuth angle β is equal to or greater than the limit angle θ (Yes in step S5), the steering angle setting unit 124 adjusts the vehicle V so that the absolute value of the azimuth angle β is smaller than the limit angle θ. is reset (step S6). For example, the steering angle setting unit 124 resets the steering angle by reducing the absolute value of the steering angle set to follow the preceding vehicle. When the steering angle setting unit 124 determines that the absolute value of the azimuth angle β is less than the limit angle θ (No in step S5), the process proceeds to step S7. Then, the steering control section 125 performs steering control of the vehicle V so as to achieve the steering angle set by the steering angle setting section 124 (step S7).

The steering control device 1 determines whether or not the control to follow the preceding vehicle continues (step S8). When the steering control device 1 determines that the control to follow the preceding vehicle is continuing (Yes in step S8), the processing from step S1 to step S8 is continued at a predetermined processing cycle. The predetermined processing period is, for example, 20 milliseconds or 30 milliseconds. When the steering control device 1 determines that the control to follow the preceding vehicle has ended (No in step S8), the process ends.

[Effects of the steering control device 1 according to the embodiment]
As described above, the steering control device 1, based on the distance L from the roadway outside line A in the direction opposite to the movement direction of the vehicle V in the lane width direction of the lane in which the vehicle V travels, to the turning center P of the vehicle V, A limit angle θ is specified so that the rear end portion Q of the vehicle V in the opposite direction to the moving direction of the vehicle V does not protrude the outside line A of the roadway. Then, the steering control device 1 sets the steering angle of the vehicle V so that the azimuth angle β of the vehicle V with respect to the direction X perpendicular to the lane width direction Y becomes smaller than the limit angle θ. The steering control of the vehicle V is performed so that the steering angle is adjusted. By doing so, the steering control device 1 can prevent the rear end portion Q of the vehicle V from exceeding the roadway outside line A and running out of the lane.

The steering control device 1 according to the embodiment can prevent the rear end portion Q of the vehicle V from running out of the lane not only when the vehicle is caused to travel following the preceding vehicle, but also in other cases. For example, the steering control device 1 executes the steering control method according to the present embodiment even when overtaking a preceding vehicle or causing a following vehicle to overtake the vehicle V so that the rear end portion Q of the vehicle V is positioned on the outside of the roadway. It is possible to prevent the vehicle from crossing the line and running out of the lane.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist thereof. be. For example, all or part of the device can be functionally or physically distributed and integrated in arbitrary units. In addition, new embodiments resulting from arbitrary combinations of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment caused by the combination has the effect of the original embodiment.

1 steering control device 2 imaging device 3 various sensors 4 motor 11 storage unit 12 control unit 121 distance identification unit 122 limit angle identification unit 123 azimuth identification unit 124 steering angle setting unit 125 steering control unit 126 curve detection unit

Claims (5)

a distance specifying unit that specifies a first distance from a roadway outside line in a direction opposite to a moving direction of the vehicle in a lane width direction of the lane in which the vehicle travels to a turning center of the vehicle;
The first distance and the second distance from the turning center to the rear end of the vehicle for preventing the rear end of the vehicle in the direction opposite to the moving direction of the vehicle from protruding from the outside line of the roadway. a limit angle specifying unit that specifies by subtracting an angle determined based on the second distance and a third distance from the turning center to the side surface of the vehicle from the angle determined according to
an azimuth angle identifying unit that identifies an azimuth angle of the vehicle based on a direction perpendicular to the lane width direction;
a steering angle setting unit that sets the steering angle of the vehicle so that the azimuth angle specified by the azimuth angle specifying unit is smaller than the limit angle specified by the limit angle specifying unit;
a steering control unit that performs steering control of the vehicle so as to achieve the steering angle set by the steering angle setting unit;
A steering control device comprising: The steering angle setting unit sets a steering angle that reduces the relative distance between the vehicle ahead of the vehicle and the vehicle in the lane width direction. reducing the absolute value of the steering angle obtained by
A steering control device according to claim 1 . The azimuth angle specifying unit determines the azimuth angle based on the steering angle or yaw rate of the vehicle up to the present time from the time when the outside line of the roadway can no longer be detected or the time when control for the vehicle to follow the preceding vehicle of the vehicle is started. identify the corners,
The steering control device according to claim 1 or 2. further comprising a curve detection unit that detects whether the vehicle is traveling on a curve,
When the curve detection unit detects that the vehicle is traveling on a curve, the steering angle setting unit does not set the steering angle such that the azimuth angle is smaller than the limit angle.
The steering control device according to any one of claims 1 to 3. executed by the processor installed in the vehicle,
identifying a first distance from a roadway outside line in a direction opposite to a moving direction of the vehicle in a lane width direction of the lane in which the vehicle travels to a turning center of the vehicle;
The first distance and the second distance from the turning center to the rear end of the vehicle for preventing the rear end of the vehicle in the direction opposite to the moving direction of the vehicle from protruding from the outside line of the roadway. a step of subtracting an angle determined based on the second distance and a third distance from the turning center to the side surface of the vehicle from the angle determined according to;
identifying the azimuth angle of the vehicle with reference to a direction perpendicular to the lane width direction;
setting the steering angle of the vehicle so that the azimuth angle is smaller than the limit angle;
a step of performing steering control of the vehicle so as to achieve the steering angle;
A steering control method comprising:

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