JP7380733B2 - Steering control device - Google Patents

Description

The present disclosure relates to a steering control device.

2. Description of the Related Art Conventionally, for example in automatic driving systems and driving support systems, steering control devices have been proposed that control steering so that a vehicle maintains within a lane. This steering control device is required to continuously detect information on the lane in which the vehicle is traveling in order to continue steering control without interruption.

Therefore, as a technique for detecting lane information on which a vehicle is traveling as seamlessly as possible, for example, Patent Document 1 discloses that the feature amount of the lane marking component that separates the left and right sides of the driving lane is extracted, and the left and right lane markings are extracted from this feature amount. When recognizing, this feature quantity is stored in the data memory, and if the marking line is interrupted and cannot be identified, when the feature quantity of the marking line component is extracted again later, the feature quantity is stored in the data memory. A technology has been disclosed that can quickly recognize the lane markings and restart driving assistance by comparing them with feature amounts and estimating the lane markings after they have been interrupted.

Patent No. 6697522

In the device of Patent Document 1, it is required to maintain steering accuracy.

An object of the present disclosure is to provide a steering control device that maintains steering accuracy.

A steering control device according to the present disclosure includes a detection unit that detects road information on which a vehicle travels, an acquisition unit that acquires vehicle position information, and calculates first lane information on which the vehicle travels based on the road information, a control unit that controls steering of the vehicle based on the first lane information; the control unit calculates information on a second lane in which the vehicle travels based on the position information, and the control unit calculates information on a second lane in which the vehicle runs based on the position information, and the control unit calculates information on a second lane in which the vehicle runs based on the position information, and the control unit In the following cases, based on the difference between the position of the first lane information and the position of the second lane information, the subsequent position of the second lane information is changed to the first lane information side and maintained, and the first lane information Then , the steering of the vehicle is controlled by switching to the changed second lane information.

According to the present disclosure, it is possible to maintain steering accuracy.

1 is a diagram showing the configuration of a vehicle equipped with a steering control device according to Embodiment 1 of the present disclosure. FIG. 3 is a diagram showing how lane information is calculated. 7 is a flowchart showing the operation of the first embodiment. FIG. 3 is a diagram showing how lane information is switched. It is a figure which shows how the position of 2nd lane information is changed. FIG. 3 is a diagram showing main parts of a steering control device according to a second embodiment.

Embodiments according to the present disclosure will be described below based on the accompanying drawings.

(Embodiment 1)
FIG. 1 shows the configuration of a vehicle 1 equipped with a steering control device according to Embodiment 1 of the present disclosure. Vehicle 1 includes a steering control device 2 and a steering section 3. Note that the steering control device 2 can control steering in, for example, an automatic driving system and a driving support system. Furthermore, examples of the vehicle 1 include a passenger car, a truck, a bus, and a van.

The steering control device 2 includes a detection section 4, an acquisition section 5, and a control section 6.

The detection unit 4 detects road information on which the vehicle 1 is traveling, and can be configured from a device that directly detects road information, such as a camera and LiDAR. The detection unit 4 can be placed at the front of the vehicle 1, for example, so as to detect road information in front of the vehicle 1. Here, the road information may include information indicating lanes, such as dividing lines (white lines) drawn on the road, road shoulders, and roadside strips.

The acquisition unit 5 acquires position information of the vehicle 1 from, for example, a satellite positioning system (for example, GNSS (Global Navigation Satellite System)), a road-to-vehicle communication unit, a road feature detection unit (for example, LiDAR, camera), etc. Can be configured. Here, the satellite positioning system is a system that directly acquires position information of the vehicle 1 measured using a satellite. Further, the road-to-vehicle communication unit is a device that directly acquires position information from a communication device installed on a road. Further, the road feature detection unit detects road feature information for specifying the position of the vehicle 1 from the map information, such as information on buildings, road structures, road signs, etc. existing around the road. Thereby, the position of the vehicle 1 can be specified by comparing the detected road characteristic information with the characteristic information included in the map information. That is, the position information includes not only information directly indicating the position of the vehicle 1 but also information for specifying the position of the vehicle 1.

The control unit 6 includes a lane information calculation unit 7 , a determination unit 8 , a vehicle position calculation unit 9 , a storage unit 10 , a switching unit 11 , a steering amount calculation unit 12 , and a steering control unit 13 .

The lane information calculation unit 7 calculates information on the first lane in which the vehicle 1 travels based on the road information detected by the detection unit 4. For example, as shown in FIG. 2, the lane information calculation unit 7 calculates information such as the position and direction of the left and right dividing lines (white lines) of the lane L in which the vehicle 1 travels. Subsequently, the lane information calculation unit 7 calculates a target travel line La so as to pass through the center of the lane L, for example, based on the information on the dividing line. Then, the lane information calculation unit 7 calculates the lateral deviation Y, the azimuth angle θ, the radius R, etc. based on the target travel line La. In this way, the first lane information can include, for example, the target driving line La, the lateral deviation Y, the azimuth θ, the radius R, and the like. Note that the lateral deviation Y may be calculated, for example, by calculating the lateral deviation of the vehicle 1 with respect to the target travel line La. Alternatively, the azimuth angle θ may be calculated as the angle of the vehicle 1 with respect to a tangent to the target travel line La. Furthermore, the radius R may be calculated as the radius of the curve of the target travel line La.

The determining unit 8 determines whether the detection level of the road information detected by the detecting unit 4 is below a predetermined threshold. Here, the predetermined threshold value can be set based on the steering stability of the vehicle 1, for example.

The storage unit 10 stores map information including roads on which the vehicle 1 travels. The map information may include, for example, information such as the position and direction of lanes provided on the road. For example, the map information may include information such as a target travel line La passing through the center of the lane L and a radius R. Furthermore, the map information may include road feature information detected by the road feature detection section.

The own vehicle position calculation unit 9 calculates the position of the vehicle 1 with respect to the lane L based on the position information of the vehicle 1 acquired by the acquisition unit 5. For example, the own vehicle position calculation unit 9 refers to the map information stored in the storage unit 10 based on the position information of the vehicle 1, and specifies the lane L in which the vehicle 1 is traveling. Then, the own vehicle position calculation unit 9 acquires the target travel line La and radius R of the specified lane L from the map information, and calculates the position of the vehicle 1 with respect to the lane L based on the position information of the vehicle 1. Then, the own vehicle position calculation unit 9 calculates the lateral deviation Y, the azimuth angle θ, etc. based on the target travel line La. At this time, the own vehicle position calculation unit 9 calculates the orientation (attitude) of the vehicle 1 based on the position of the immediately preceding vehicle 1 (for example, information on the previous vehicle 1), and based on the orientation of the vehicle 1. The lateral deviation Y and the azimuth angle θ may also be calculated. In this way, second lane information such as the target travel line La, lateral deviation Y, azimuth θ, and radius R is calculated based on the position information of the vehicle 1.

The switching unit 11 switches the lane information to be output to the steering amount calculation unit 12 based on the determination result of the determination unit 8 . Specifically, when the determination unit 8 determines that the road information detection level exceeds a predetermined threshold, the switching unit 11 switches the first lane information calculated by the lane information calculation unit 7 to the steering wheel. It is output to the quantity calculation section 12. On the other hand, when the determination unit 8 determines that the road information detection level is below the predetermined threshold, the switching unit 11 transmits the second lane information calculated by the own vehicle position calculation unit 9 to the steering amount calculation unit 12. Output.

The steering amount calculating section 12 calculates the steering amount of the vehicle 1 based on the first lane information output from the switching section 11 . Here, when the switching unit 11 switches from the first lane information to the second lane information, the steering amount calculating unit 12 calculates the steering amount of the vehicle 1 based on the second lane information. In this way, the steering amount calculation unit 12 calculates the steering amount of the vehicle 1 by switching between the first lane information and the second lane information.
Note that examples of the steering amount include a target steering angle and a target steering torque.

The steering control section 13 controls the steering section 3 based on the steering amount calculated by the steering amount calculation section 12. The steering control section 13 can control the steering section 3 by, for example, outputting a current or voltage to the steering section 3 according to the amount of steering.

The steering unit 3 steers the vehicle 1 by changing the angle of the wheels, and is composed of, for example, a motor and an actuator. The steering unit 3 changes the direction of the wheels by an angle corresponding to the current or voltage output from the steering control unit 13, for example.

Next, the operation of this embodiment will be explained with reference to the flowchart of FIG.

First, the detection unit 4 sequentially detects road information in accordance with the travel of the vehicle 1 in step S1. The detection unit 4 includes, for example, a camera that photographs the front of the vehicle 1, and detects road information by generating an image including road information. The detection unit 4 outputs an image including road information to the lane information calculation unit 7.
Further, the acquisition unit 5 acquires position information of the vehicle 1. The acquisition unit 5 is configured to acquire position information of the vehicle 1 from, for example, a satellite positioning system, and sequentially acquires position information that changes as the vehicle 1 travels. The acquisition unit 5 outputs the acquired position information to the own vehicle position calculation unit 9.

When the lane information calculation unit 7 receives the image detected by the detection unit 4, it calculates information on the first lane in which the vehicle 1 is traveling from the image in step S2. For example, as shown in FIG. 2, the lane information calculation unit 7 extracts road information such as dividing lines from the image, and calculates information such as the position and direction of the lane L in which the vehicle 1 runs from the extracted road information. do. The lane information calculation unit 7 calculates a target travel line La based on the information on the lane L, and calculates a lateral deviation Y, an azimuth θ, a radius R, etc. based on the target travel line La. In this way, after calculating the first lane information such as the target driving line La, the lateral deviation Y, the azimuth angle θ, and the radius R, the lane information calculation unit 7 outputs the first lane information to the switching unit 11. Further, the lane information calculation unit 7 outputs information of the image detected by the detection unit 4, such as first lane information, to the determination unit 8.

Subsequently, the determination unit 8 determines whether the detection level of the road information is equal to or lower than a predetermined threshold based on the information of the image detected by the detection unit 4. Here, the value of the first lane information tends to become more blurred as the detection level decreases. For example, when calculating a function indicating the lane L based on the dividing line, the number of detected dividing lines decreases as the detection level decreases, so the deviation of the function for the lane L increases. Therefore, the determination unit 8 may determine the detection level of the road information based on the blur of the first lane information calculated by the lane information calculation unit 7, for example. The determination section 8 outputs the detection level determination result to the switching section 11 .

On the other hand, when the vehicle position calculation unit 9 receives the position information of the vehicle 1 acquired by the acquisition unit 5, it refers to the map information stored in the storage unit 10 based on the position information, and the vehicle 1 runs. Identify lane L. Then, the own vehicle position calculation unit 9 acquires the target travel line La and radius R of the identified lane L from the map information, and calculates information on the second lane in which the vehicle 1 runs based on the acquired information. For example, the own vehicle position calculation unit 9 calculates the lateral deviation Y, the azimuth angle θ, etc. based on the position of the vehicle 1 and the target travel line La. In this way, after calculating the second lane information such as the position of the vehicle 1, the target driving line La, the lateral deviation Y, the azimuth angle θ, and the radius R, the own vehicle position calculation unit 9 switches the second lane information. It is output to section 11.

In this way, the first lane information, the second lane information, and the detection level determination result are sequentially input to the switching unit 11. In step S3, the switching unit 11 refers to the determination result of the determining unit 8, and if the determination result (first signal) is that the detection level of road information exceeds a predetermined threshold, the switching unit 11 switches to step S4. Then, the first lane information is output to the steering amount calculation section 12.

Thereby, the steering amount calculating section 12 calculates the steering amount based on the first lane information input from the switching section 11. For example, the steering amount calculation unit 12 can calculate a target steering angle with respect to the current steering angle, that is, a steering angle for maintaining the target travel line La as the steering amount. The steering amount calculation unit 12 outputs the calculated steering amount to the steering control unit 13.

Subsequently, the steering control section 13 controls the steering section 3 based on the steering amount calculated by the steering amount calculation section 12. Thereby, the vehicle 1 is steered to travel along the target travel line La.

Here, there may be a case where the detection level of the road information in the detection unit 4 decreases. For example, if the lane L dividing line is partially removed due to wear, the dividing line is not detected due to a wet road surface, or the dividing line is hidden by snow, the detection level of road information may decrease. .

Therefore, when the switching unit 11 determines in step S3 that the detection level of the road information is less than or equal to the predetermined threshold (second signal), the switching unit 11 proceeds to step S5 and calculates the steering amount from the second lane information. output to section 12.

Thereby, the steering amount calculation unit 12 switches from the first lane information to the second lane information and calculates the steering amount of the vehicle 1. The steering amount calculation unit 12 can calculate the steering amount based on the second lane information, similarly to the first lane information. The steering amount calculation unit 12 outputs the calculated steering amount to the steering control unit 13. Then, the steering control section 13 controls the steering section 3 based on the steering amount calculated by the steering amount calculation section 12.

In this way, when the detection level of the road information is below a predetermined threshold, the control unit 6 controls the steering of the vehicle by switching from the first lane information to the second lane information. Since this second lane information is calculated based on map information that is not affected by a decrease in the detection level, steering accuracy can be maintained even if the detection level decreases.

Here, the control unit 6 may change the second lane information so that the value of the lane information does not change significantly in response to switching from the first lane information to the second lane information.

For example, as shown in FIG. 4, consider a case where the positions of the target travel line L1 of the first lane information and the target travel line L2 of the second lane information are shifted in the vehicle width direction of the lane L. The control unit 6 calculates the lateral deviation Y, azimuth θ, and radius R based on the target driving line L1, and controls the steering based on the lateral deviation Y, azimuth θ, and radius R, that is, calculates the first lane information. It is assumed that the steering is controlled based on the At this time, when the first signal is switched to the second signal at time t1 (when the road information detection level is determined to be below a predetermined threshold), for example, the target driving line L1 is directly switched to the target driving line L2. As a result, the position of the target travel line changes significantly in a stepwise manner. Therefore, the amount of steering of the vehicle 1 calculated based on the target travel line L2 may also change significantly. In particular, when calculating the amount of steering of the vehicle 1 based on a value obtained by differentiating lane information, there is a possibility that the amount of steering changes suddenly.

Therefore, the control unit 6 changes the position of the second lane information based on the difference from the position of the first lane information, and controls the steering of the vehicle based on the changed second lane information.

For example, as shown in FIG. 5, when the first signal is switched to the second signal at time t1, the steering amount calculation unit 12 calculates the difference in position between the target travel line L1 and the target travel line L2. Then, the steering amount calculation unit 12 changes the position of the target travel line L2 to move toward the target travel line L1 by the calculated difference value. That is, the steering amount calculation unit 12 changes the position of the target travel line L2 by sequentially adding the calculated difference values to the target travel line L2. As a result, a target travel line L3 is generated in which the target travel line L1 and the target travel line L2 are continuously connected.
The steering amount calculation unit 12 also changes other second lane information such as lateral deviation Y, azimuth θ, and radius R based on the difference in position between the first lane information and the second lane information. I can do it. Subsequently, the steering amount calculation unit 12 calculates the steering amount based on the changed lateral deviation Y, azimuth angle θ, and radius R. Then, the steering control section 13 controls the steering section 3 based on the steering amount calculated by the steering amount calculation section 12.

In this way, when the detection level of the road information is below a predetermined threshold, the control unit 6 changes the position of the second lane information based on the difference from the position of the first lane information, and The steering of the vehicle 1 is controlled based on the two lane information. Thereby, it is possible to suppress a change in the amount of steering in response to switching from the first lane information to the second lane information, and it is possible to smoothly steer the vehicle 1.

Further, the control unit 6 changes the position of the second lane information so as to move it to the first lane information side by the value of the difference. Thereby, the vehicle 1 can be steered more smoothly.

In this way, when the control unit 6 switches from the first lane information to the second lane information at time t1, the steering amount after time t1 sequentially changes the position of the second lane information based on the difference value. The steering amount of the vehicle 1 is controlled based on the calculated steering amount.

According to this embodiment, when the detection level of the road information is below a predetermined threshold, the control unit 6 controls the steering of the vehicle by switching from the first lane information to the second lane information. As a result, the steering amount is calculated based on the second lane information that is not affected by a decrease in the detection level, so even if the detection level decreases, the accuracy of steering can be maintained.

(Embodiment 2)
Embodiment 2 of the present disclosure will be described below. Here, differences from the first embodiment described above will be mainly explained, and common points with the first embodiment described above will be denoted by common reference numerals, and detailed explanation thereof will be omitted.

In the first embodiment described above, the steering control device 2 may arrange a plurality of acquisition units.

For example, as shown in FIG. 6, two acquisition sections 21 and 22 may be arranged in place of the acquisition section 5 of the first embodiment, and a determination section 23 may be newly connected to the own vehicle position calculation section 9.

The acquisition unit 21 and the acquisition unit 22 acquire different types of position information.
The acquisition unit 21 may acquire position information of the vehicle 1 measured using a satellite, for example. The acquisition unit 21 can be configured from, for example, a satellite positioning system such as GNSS (Global Navigation Satellite System).

Further, the acquisition unit 22 may detect road characteristic information for specifying the position of the vehicle 1, for example, information on buildings, road structures, road signs, etc. existing around the road, as the position information. The acquisition unit 22 can be configured from a road feature detection unit such as LiDAR and a camera, for example.

The own vehicle position calculation unit 9 refers to map information based on the position information of the vehicle 1 acquired by the acquisition unit 21 and calculates second lane information. Further, the own vehicle position calculation unit 9 identifies the position of the vehicle 1 by comparing the road characteristic information acquired by the acquisition unit 22 with the characteristic information included in the map information, and based on the position of the vehicle 1. Then, the second lane information is calculated.

The determination unit 23 determines specific position information indicating the position of the vehicle 1 with high accuracy from among the two position information acquired by the acquisition units 21 and 22. The determining unit 23 may determine, for example, specific positional information with the highest positional accuracy.

Next, the operation of this embodiment will be explained.

First, similarly to the first embodiment, the lane information calculation section 7 calculates first lane information based on the road information detected by the detection section 4, and outputs the first lane information to the switching section 11.
On the other hand, the acquisition unit 21 acquires the position information of the vehicle 1 measured by the satellite positioning system, and the acquisition unit 22 acquires the position information of the vehicle 1 consisting of road characteristic information. The acquisition units 21 and 22 each output the acquired position information of the vehicle 1 to the own vehicle position calculation unit 9. Then, the own vehicle position calculation unit 9 calculates the second lane information based on the position information of the vehicle 1 output from the acquisition unit 21, and also calculates the second lane information based on the position information of the vehicle 1 acquired by the acquisition unit 22. Calculate 2 lane information.

The own vehicle position calculation section 9 outputs the calculated second lane information to the switching section 11. The own vehicle position calculation unit 9 also receives information indicating the accuracy of the position information acquired by the acquisition units 21 and 22, such as the number of satellites whose position information has been acquired by the acquisition unit 21, and the number of roads acquired by the acquisition unit 22. The number of matches between the feature information and the feature information of the map information is output to the determination unit 23.

The determining unit 23 determines specific positional information of the vehicle 1 with high positional accuracy from among the two pieces of positional information acquired by the acquiring units 21 and 22. For example, the determination unit 23 can determine the position accuracy of the acquisition unit 21 based on whether the number of satellites from which position information is acquired is greater than or equal to a predetermined number. Further, the determination unit 23 can determine the position accuracy of the acquisition unit 22 based on whether the number of matches between the road characteristic information and the characteristic information included in the map information is equal to or greater than a predetermined number.
Here, it is assumed that the determination unit 23 determines that the positional information acquired by the acquisition unit 21 has higher positional accuracy of the vehicle 1 than the positional information acquired by the acquisition unit 22. The determination section 23 outputs the determination result to the switching section 11.

In step S3, if the detection level of the road information is determined to be less than or equal to a predetermined threshold, the switching unit 11 selects one of the two pieces of second lane information calculated by the host vehicle position calculation unit 9 from the determination unit. 23, the second lane information determined to have high positional accuracy, that is, the second lane information calculated based on the positional information of the acquisition unit 21, is selected. Then, the switching unit 11 outputs the selected second lane information to the steering amount calculation unit 12.

In this way, the switching unit 11 selects the second lane information calculated based on the specific positional information with high positional accuracy of the vehicle 1 from among the two pieces of positional information acquired by the acquisition units 21 and 22. Thereby, the steering amount is calculated based on the second lane information with high positional accuracy, so the vehicle 1 can be steered with high precision.

According to the present embodiment, the control unit 6 selects the second position information based on the specific position information, of which the position accuracy of the vehicle 1 is higher than the other position information, among the two position information acquired by the acquisition units 21 and 22. Calculate lane information. Thereby, the vehicle 1 can be steered with high precision based on the second lane information.

Although the embodiments according to the present disclosure have been described above in detail with reference to the drawings, the functions of each device described above can be realized by a computer program.

A computer that realizes the functions of each device described above through programs includes input devices such as a keyboard, mouse, and touch pad, output devices such as a display and speakers, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random). Access Memory), storage devices such as hard disk drives and SSD (Solid State Drive), DVD-ROM (Digital Versatile Disk Read Only Memory) and USB (Universal Serial Bus) memory Reading devices and networks that read information from recording media such as Each part is connected by a bus, including a network card for communication.

Then, the reading device reads a program for realizing the functions of each of the above devices from a recording medium in which the program is recorded, and stores the program in the storage device. Alternatively, the network card communicates with a server device connected to the network, and causes the storage device to store programs downloaded from the server device to implement the functions of each device.

Then, the CPU copies the program stored in the storage device to the RAM, and sequentially reads out and executes the instructions included in the program from the RAM, thereby realizing the functions of each of the devices described above.

Although specific examples of the present disclosure have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples illustrated above.

The steering control device according to the present disclosure can be used as a device for controlling the steering of a vehicle.

1 Vehicle 2 Steering control device 3 Steering section 4 Detection section 5, 21, 22 Acquisition section 6 Control section 7 Lane information calculation section 8 Judgment section 9 Own vehicle position calculation section 10 Storage section 11 Switching section 12 Steering amount calculation section 13 Steering control Part 23 Judgment part L Lane La, L1, L2, L3 Target travel line R Radius t1 Time Y Lateral deviation θ Azimuth

Claims (4)

a detection unit that detects road information on which the vehicle is traveling;
an acquisition unit that acquires position information of the vehicle;
a control unit that calculates first lane information in which the vehicle travels based on the road information and controls steering of the vehicle based on the first lane information;
Equipped with
The control unit calculates information on a second lane in which the vehicle travels based on the position information, and when the detection level of the road information is equal to or lower than a predetermined threshold, the control unit calculates information on a second lane in which the vehicle travels based on the position information, and calculates information on a second lane in which the vehicle runs based on the position information on the first lane information and the second lane information. Based on the difference with the position of the lane information, the subsequent position of the second lane information is changed to the first lane information side and maintained, and the first lane information is switched to the changed second lane information . A steering control device that controls the steering of the vehicle. The detection unit includes a camera that photographs the road information,
The steering control device according to claim 1, wherein the acquisition unit acquires the position information from a satellite positioning system. The acquisition unit acquires a plurality of different types of position information,
The steering control according to claim 1 or 2, wherein the control unit calculates the second lane information based on specific position information, among the plurality of position information, in which the position accuracy of the vehicle is higher than other position information. Device. The steering control device according to any one of claims 1 to 3, wherein the control unit changes the position of the second lane information so as to shift the position of the second lane information toward the first lane information by the value of the difference.