Steering control system

Abstract

To provide a steering control device that is able to calculate a learning value for correcting a target lateral position according to the magnitude of influence on an error in the vehicle lateral position caused by deviation of a mounting position.SOLUTION: A steering control device 100 executes steering control including steering assistance or automatic steering of a vehicle 20. The steering control device 100 includes: a path generation unit 14 that generates a target path including a target lateral position, based on a captured image showing ahead of the vehicle 20; a learning-value calculation unit 15 that calculates a learning value for correcting the target lateral position, based on an amount of deviation from the target lateral position that a manual path of the vehicle 20 following a manual steering operation has with respect to the target path when a driver of the vehicle 20 performs the manual steering operation during the execution of the steering control; and a vehicle control unit 16 that executes the steering control, based on the target path and the learning value. The learning-value calculation unit 15 calculates a first learning-value, which is a learning value when the vehicle 20 is traveling on a straight road; and a second learning-value, which is a learning value when the vehicle 20 is traveling on a curved road.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a steering control device.

Background Art

[0002] In the vehicle position estimation device described in Patent Document 1, when it is determined that there is a steering override, the vehicle lateral position control is interrupted, and then, when it is determined that the steering override has ended, the vehicle lateral position control is restarted. The difference between the vehicle position based on GPS information and the vehicle position based on map information is regarded as the inherent position error of the GPS information, and this inherent position error is reflected in the vehicle position at the end of the steering override.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, for example, when there is an assembly error at the shipping stage and when the user accidentally touches the camera and its orientation is shifted, the mounting posture of a camera or the like used for steering control may deviate from the ideal state. The influence of such a deviation in the mounting posture on the error of the vehicle lateral position is not necessarily uniform between straight roads and curves. Therefore, there has been room for improvement in error correction.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a steering control device that performs steering control including steering assistance or automatic steering of a vehicle, comprising: a path generation unit that generates a target path including a target lateral position in the vehicle's driving lane based on an image captured in front of the vehicle; a learning value calculation unit that calculates a learning value to correct the target lateral position based on the amount of deviation from the target lateral position of the manual path of the vehicle following the manual steering operation when the vehicle driver is performing a manual steering operation during the execution of steering control; and a steering control unit that performs steering control based on the target path and the learning value, wherein the learning value calculation unit calculates a first learning value which is the learning value when the vehicle is traveling on a straight road and a second learning value which is the learning value when the vehicle is traveling on a curved road.

[0006] In a steering control device according to one aspect of this disclosure, a first learning value for straight roads and a second learning value for curved roads are calculated as learning values ​​for correcting the target lateral position. Here, errors in the vehicle's lateral position on the road on which the vehicle travels can occur due to deviations in the mounting orientation of the camera that acquires the captured image. Errors in the vehicle's lateral position due to deviations in mounting orientation are not necessarily uniform, and may be larger on curved roads than on straight roads, for example. According to the above configuration, the first learning value for straight roads and the second learning value for curved roads can be calculated as different values ​​from each other. Therefore, it is possible to calculate a learning value for correcting the target lateral position according to the magnitude of the influence of deviations in mounting orientation on the error in the vehicle's lateral position.

[0007] In one embodiment, the learning value calculation unit may calculate a right learning value, which is a second learning value when the vehicle is traveling on a right-hand curve, and a left learning value, which is a second learning value when the vehicle is traveling on a left-hand curve. The effect of deviations in mounting posture on the error in the vehicle's lateral position is not necessarily uniform when the vehicle is traveling on a right-hand curve and when the vehicle is traveling on a left-hand curve. With the above configuration, the right learning value for right-hand curves and the left learning value for left-hand curves can be calculated as different values ​​from each other. Therefore, the second learning values ​​can be calculated in accordance with the difference in the magnitude of the effect on the error in the vehicle's lateral position caused by deviations in mounting posture between right-hand curves and left-hand curves.

[0008] In one embodiment, the learning value calculation unit may calculate the learning values ​​such that the learning speed of the second learning value is faster than the learning speed of the first learning value. In this case, by making the learning speed when driving on a curved road faster than the learning speed when driving on a straight road, the vehicle's lateral position can be corrected earlier on curved roads, where the impact on the error of the vehicle's lateral position tends to be greater. [Effects of the Invention]

[0009] According to various aspects of this disclosure, a learned value can be calculated to correct the target lateral position according to the magnitude of the impact of deviations in mounting posture on errors in the vehicle's lateral position. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of an example of a vehicle including a steering control device according to an embodiment. [Figure 2] This is a plan view illustrating the calculation of a learned value that corrects the target lateral position based on the amount of deviation from the target lateral position. [Figure 3] This is a flowchart showing an example of the process for calculating learned values. [Figure 4] Figure 3 is a flowchart showing an example of the calculation process for the second learned value. [Figure 5] This flowchart shows an example of the process for setting the learning speed. [Modes for carrying out the invention]

[0011] The following describes exemplary embodiments with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant descriptions may be omitted.

[0012] Figure 1 is a schematic diagram of an example of a vehicle including a steering control device according to an embodiment. The steering control device 100 shown in Figure 1 is an automatic driving device mounted on a vehicle 20, such as a passenger car. The steering control device 100 is configured to perform steering control, including steering assistance for the vehicle 20. Steering assistance is a driving state that controls the vehicle to assist the driver's steering operation of the vehicle 20. Steering assistance is, for example, lane keeping assist (LKA), which prompts the driver to steer the vehicle 20 so as not to deviate from the driving lane.

[0013] The steering control device 100 may be configured to perform steering control, including automatic steering of the vehicle 20. Automatic steering is a driving state in which the steering of the vehicle 20 is automatically controlled. Automatic steering may, for example, automatically steer the vehicle 20 to prevent it from deviating from the driving lane by the LKA control described above, without any steering operation of the vehicle 20 by the driver.

[0014] The steering control device 100 may be configured to perform automated driving, including automatic steering. Automated driving is a vehicle control system that causes the vehicle 20 to automatically travel along a pre-set target route. The target route here is the path on a map along which the vehicle 20 travels in automated driving control. In automated driving, the driver does not need to perform steering or acceleration / deceleration operations, and the vehicle 20 travels automatically.

[0015] In other words, the steering control of this embodiment means LKA control that includes at least one of steering assistance, automatic steering when not in autonomous driving mode, and automatic steering when in autonomous driving mode. Of the above LKA control, steering assistance and automatic steering when not in autonomous driving mode can be performed, for example, based on images captured in front of the vehicle 20 by an onboard camera. Each of the above LKA control may further be performed based on map information.

[0016] [Configuration of the steering control device 100] As shown in FIG. 1, the steering control device 100 includes an ECU [Electronic Control Unit] 10 that oversees steering control. The ECU 10 is an electronic control unit having a CPU [Central Processing Unit], ROM [Read Only Memory], RAM [Random Access Memory], a CAN [Controller Area Network] communication circuit, and the like. In the ECU 10, for example, a program stored in the ROM is loaded into the RAM, and various functions are realized by executing the program loaded into the RAM with the CPU. The ECU 10 may be composed of a plurality of electronic control units.

[0017] The ECU 10 is connected to a GPS [Global Positioning System] receiver 1, an external sensor 2, an internal sensor 3, a map database 4, and an actuator 5.

[0018] The GPS receiver 1 measures the position of the vehicle 20 (for example, the latitude and longitude of the vehicle 20) by receiving signals from three or more GPS satellites. The GPS receiver 1 transmits the measured position information of the vehicle 20 to the ECU 10.

[0019] The external sensor 2 is a detector that detects the situation around the vehicle 20. The external sensor 2 includes at least a camera. The external sensor 2 may include a radar sensor.

[0020] The camera is an imaging device that images the external situation of the vehicle 20. The camera is provided on the back side of the front glass of the vehicle 20. The camera transmits an imaging image regarding the external situation including the front of the vehicle 20 to the ECU 10. The camera may be a monocular camera or a stereo camera.

[0021] The radar sensor is a detector that uses radio waves (e.g., millimeter waves) or light to detect obstacles around the vehicle 20. The radar sensor includes, for example, a millimeter wave radar or a lidar [LIDAR: Light Detection And Ranging]. The radar sensor transmits radio waves or light around the vehicle 20 and detects the obstacles by receiving the radio waves or light reflected by the obstacles. The radar sensor transmits the detected obstacle information to the ECU 10. The obstacles include, for example, fixed obstacles that define the lanes of the road, such as curbs, guardrails, poles, or safety cones. The obstacles may include moving obstacles such as pedestrians, bicycles, and other vehicles.

[0022] The internal sensor 3 is a detector that detects the driving state of the vehicle 20. The internal sensor 3 includes a vehicle speed sensor, an acceleration sensor, and a yaw rate sensor. The vehicle speed sensor is a detector that detects the speed of the vehicle 20. As the vehicle speed sensor, for example, a wheel speed sensor provided for the wheels of the vehicle 20 or a drive shaft that rotates integrally with the wheels to detect the rotational speed of the wheels is used. The vehicle speed sensor transmits the detected vehicle speed information (wheel speed information) to the ECU 10.

[0023] The acceleration sensor is a detector that detects the acceleration of the vehicle 20. The acceleration sensor includes, for example, a longitudinal acceleration sensor that detects the longitudinal acceleration of the vehicle 20 and a lateral acceleration sensor that detects the lateral acceleration of the vehicle 20. The acceleration sensor transmits, for example, the acceleration information of the vehicle 20 to the ECU 10. The yaw rate sensor is a detector that detects the yaw rate (rotational angular velocity) around the vertical axis of the center of gravity of the vehicle 20. As the yaw rate sensor, for example, a gyro sensor can be used. The yaw rate sensor transmits the detected yaw rate information of the vehicle 20 to the ECU 10.

[0024] Map database 4 is a database that stores map information. Map database 4 is formed in a storage device such as an HDD (Hard Disk Drive) installed in the vehicle 20. Map information includes road location information, road shape information (e.g., type of curves and straight sections, curvature of curves, whether a curve is a right or left curve, etc.), and location information of intersections and junctions. Note that map database 4 is not required unless the vehicle 20 is configured to perform autonomous driving.

[0025] Actuator 5 is a device used to control the vehicle 20. Actuator 5 includes at least a steering actuator. The steering actuator controls the drive of the assist motor that controls the steering torque of the electric power steering system in accordance with a control signal from the ECU 10. In this way, the steering actuator controls the steering torque of the vehicle 20.

[0026] The actuator 5 may include a drive actuator and a brake actuator. The drive actuator controls the amount of air supplied to the engine (throttle opening) in response to a control signal from the ECU 10, thereby controlling the driving force of the vehicle 20. If the vehicle 20 is a hybrid vehicle, in addition to the amount of air supplied to the engine, a control signal from the ECU 10 is input to the motor, which is a power source, to control its driving force. If the vehicle 20 is an electric vehicle, a control signal from the ECU 10 is input to the motor, which is a power source, to control its driving force. In these cases, the motor, which is a power source, constitutes the actuator 5. The brake actuator controls the brake system in response to a control signal from the ECU 10, thereby controlling the braking force applied to the wheels of the vehicle 20. As the brake system, for example, a hydraulic brake system can be used.

[0027] Next, the functional configuration of the ECU 10 will be described. The ECU 10 includes a surrounding environment recognition unit 11, a vehicle position recognition unit 12, a driving state recognition unit 13, a route generation unit 14, a learned value calculation unit 15, and a vehicle control unit (steering control unit) 16. Some of the functions of the ECU 10 may be executed on a server that can communicate with the vehicle 20.

[0028] The surrounding environment recognition unit 11 recognizes the surrounding environment of the vehicle 20 based on the detection results of the external sensor 2. The surrounding environment includes the condition of the lane markings (e.g., white lines) around the vehicle 20. The surrounding environment may also include the condition of obstacles (including curbs) around the vehicle 20.

[0029] The surrounding environment recognition unit 11 uses the camera of the external sensor 2 to acquire an image of the area in front of the vehicle 20. Based on the image of the area in front of the vehicle 20, the surrounding environment recognition unit 11 recognizes the lane markings around the vehicle 20 and the lane in which the vehicle 20 is traveling. The surrounding environment recognition unit 11 may also use the radar sensor of the external sensor 2 to acquire information on obstacles such as curbs in front of the vehicle 20 and recognize the lane in which the vehicle 20 is traveling.

[0030] The vehicle position recognition unit 12 recognizes the position of the vehicle 20 on the driving lane or the position of the vehicle 20 on a map. The vehicle position recognition unit 12 recognizes the relative position of the vehicle 20 and the lane markings based on, for example, an image captured in front of the vehicle 20 using the camera of the external sensor 2, and recognizes the position of the vehicle 20 on the driving lane. The position of the vehicle 20 on the driving lane may be determined, for example, as coordinates corresponding to the midpoint of the left and right drive wheels of the vehicle 20.

[0031] Furthermore, if the vehicle 20 is configured to perform automatic steering during autonomous driving, the vehicle position recognition unit 12 may recognize the position of the vehicle 20 on the map based on the position information of the GPS receiver unit 1 and the map information of the map database 4. The vehicle position recognition unit 12 may accurately recognize the position of the vehicle 20 using SLAM (Simultaneous Localization and Mapping) technology or the like, by utilizing the position information of targets included in the map information of the map database 4 and the detection results of the external sensor 2. The vehicle position recognition unit 12 may also recognize the position of the vehicle 20 on the map by other well-known methods.

[0032] The driving state recognition unit 13 recognizes the driving state of the vehicle 20 based on the detection results of the internal sensor 3. The driving state includes the vehicle speed of the vehicle 20, the acceleration of the vehicle 20, and the yaw rate of the vehicle 20. Specifically, the driving state recognition unit 13 recognizes the vehicle speed of the vehicle 20 based on the vehicle speed information from the vehicle speed sensor. The driving state recognition unit 13 recognizes the acceleration of the vehicle 20 based on the acceleration information from the acceleration sensor. The driving state recognition unit 13 recognizes the orientation of the vehicle 20 based on the yaw rate information from the yaw rate sensor.

[0033] The driver of vehicle 20 can perform manual steering operations while steering control is being performed. Manual steering operations are operations that override steering operations while steering control is being performed. The driving state recognition unit 13 may determine, for example, whether or not a manual steering operation occurred while steering control was being performed, based on whether or not steering operations by the driver were detected by a steering angle sensor or a steering torque sensor, etc.

[0034] The route generation unit 14 generates a target route, including the target lateral position of the vehicle 20 in the driving lane, based on the captured image of the area in front of the vehicle 20. The target route can be, for example, target lateral position data (lateral position profile) of the vehicle 20 on the driving lane. The target lateral position data may be the position of the vehicle 20 on the driving lane, for example, a set vertical position set at predetermined intervals (e.g., 1 m) in the direction of travel of the vehicle 20 in the driving lane. The target lateral position is the target position in the width direction of the lane. In this case, the set vertical position and the target lateral position may be set together as a single position coordinate. The lateral position profile corresponds to trajectory data represented by associating the target lateral position with each set vertical position.

[0035] Furthermore, if the vehicle 20 is configured to perform automatic steering during autonomous driving, the path generation unit 14 may generate a path used when the vehicle 20 performs autonomous driving using various methods.

[0036] Figure 2 is a plan view illustrating the calculation of a learned value that corrects the target lateral position based on the amount of deviation from the target lateral position. In the example in Figure 2, a vehicle 20 is shown in a plan view traveling on a straight road 30 while KLA control is being performed as steering control. The position of the vehicle 20 on the road is the center position 21, indicated by the black dot. The target path of the KLA control is the target path 22, indicated by the dashed straight line. The amount of deviation from the target lateral position corresponds to the deviation amount 23, which is the distance between the center position 21 and the target path 22 in the lane width direction.

[0037] In vehicle 20, if no manual steering operation is performed while steering control is in progress, the actuator 5 is controlled so that the center position 21 is located on the target path 22 of the steering control. In the example in Figure 2, manual steering operation is performed by the driver while steering control is in progress in vehicle 20. For example, because the target path 22 is shifted to the right on the driving lane, this corresponds to a situation where the driver is performing a steering operation to slightly steer the vehicle 20 to the left so that it travels near the center of the driving lane. The phenomenon of the target path 22 being shifted to the right on the driving lane signifies the influence on the error in the vehicle's lateral position caused by the misalignment of the mounting posture of the camera of the external sensor 2 on vehicle 20. Note that in Figure 2, the amount by which the target path 22 is shifted to the right on the driving lane is exaggerated and shown as larger.

[0038] The learning value calculation unit 15 calculates a learning value to correct the target lateral position based on the amount of deviation 23 from the target lateral position of the manual path of the vehicle 20 following the manual steering operation when the driver of the vehicle 20 is performing a manual steering operation during the execution of steering control, relative to the target path 22.

[0039] The manual path of vehicle 20 following manual steering operation corresponds to the movement trajectory of the center position 21 of vehicle 20 as it travels in response to the manual steering operation performed during the execution of steering control. The manual path of vehicle 20 extends away from the target path 22 depending on the amount of manual steering operation. In the example in Figure 2, the manual path of vehicle 20 following manual steering operation can be assumed to be, for example, a virtual line along the solid arrow indicating the direction in which vehicle 20 is traveling.

[0040] The learning value calculation unit 15 calculates a first learning value, which is the learning value when the vehicle 20 is traveling on a straight road, and a second learning value, which is the learning value when the vehicle 20 is traveling on a curved road. The example in Figure 2 corresponds to the case when the vehicle 20 is traveling on a straight road. Even when the vehicle 20 is traveling on a curved road, the center position 21, target path 22, and deviation amount 23 can be defined in the same way as in the example in Figure 2. The first learning value and the second learning value are learning values ​​for straight roads and curved roads, respectively, and can be stored separately in the ECU 10.

[0041] The learning value calculation unit 15 determines, for example, whether the vehicle 20 is traveling on a straight road or a curved road, based on the image captured in front of the vehicle 20 and the shape of the lane markings in front of the vehicle 20. The learning value calculation unit 15 may also determine whether the vehicle 20 is traveling on a curved road based on the vehicle 20's position on the map and map information.

[0042] The learning value calculation unit 15 may calculate a right learning value, which is a second learning value when the vehicle 20 is traveling on a right curve, and a left learning value, which is a second learning value when the vehicle 20 is traveling on a left curve. The right learning value and the left learning value are learning values ​​for right curves and left curves, respectively, and can be stored separately in the ECU 10.

[0043] The learned value calculation unit 15, for example, determines whether the vehicle 20 is traveling on a right-hand curve based on the image captured in front of the vehicle 20, according to the direction of the curvature of the lane markings in front of the vehicle 20. The learned value calculation unit 15 may also determine whether the vehicle 20 is traveling on a right-hand curve based on the vehicle 20's position on the map and map information.

[0044] The learning value calculation unit 15 may calculate the learning values ​​such that the learning speed of the second learning value is faster than the learning speed of the first learning value. The learning value calculation unit 15 can change the learning speed by changing the calculation cycle of the learning value calculation process.

[0045] The learning value calculation unit 15 sets the learning value calculation speed to the first learning speed by setting the calculation cycle of the learning value calculation process to the first cycle when the vehicle 20 is traveling on a straight road. The learning value calculation unit 15 sets the learning value calculation speed to the second learning speed by setting the calculation cycle of the learning value calculation process to the second cycle when the vehicle 20 is traveling on a curved road. The second cycle is a shorter learning value update cycle than the first cycle. As a result, the second learning speed is a faster learning value calculation speed than the first learning speed.

[0046] The vehicle control unit 16 performs steering control based on the target path and learned values. If manual steering is performed while steering control is being executed, the vehicle control unit 16 may interrupt the execution of steering control and wait for the calculation of the learned value by the learned value calculation unit 15 described above. Depending on the learned value calculated by the learned value calculation unit 15 described above, the vehicle control unit 16 may resume the execution of steering control if no manual steering is performed while steering control is being executed. For example, the vehicle control unit 16 may correct the position in the vehicle width direction of the target path with the stored learned value and execute steering control with the corrected position in the vehicle width direction as the target.

[0047] In the example shown in Figure 2, it is assumed that if manual steering is performed while steering control is in operation, a learned value corresponding to the deviation amount 23 is stored. In this case, when manual steering is no longer performed while steering control is in operation, the target path 22 is corrected in the vehicle width direction by the amount of deviation 23. As a result, steering control is performed so that the center position 21 moves along the solid arrow.

[0048] Furthermore, when the vehicle 20 performs autonomous driving, the vehicle control unit 16 may function to perform autonomous driving of the vehicle 20 based on the route generated by the route generation unit 14. Steering control as described above may be performed as part of the autonomous driving of the vehicle 20.

[0049] [An example of calculation processing by ECU10] Next, an example of calculation processing by the ECU 10 will be described. Figure 3 is a flowchart showing an example of the learning value calculation process. The process shown in Figure 3 is repeated at predetermined intervals, for example, while steering control, including steering assistance or automatic steering, is being performed on the vehicle 20.

[0050] As shown in Figure 3, in S01, the ECU 10 uses the surrounding environment recognition unit 11 to acquire an image of the area in front of the vehicle 20. The surrounding environment recognition unit 11 uses the camera of the external sensor 2 to acquire an image of the area in front of the vehicle 20.

[0051] In S02, the ECU 10 generates a target route using the route generation unit 14. The route generation unit 14 generates a target route, including the target lateral position of the vehicle 20 in its driving lane, based on the captured image of the area in front of the vehicle 20.

[0052] In S03, the ECU 10 uses a learning value calculation unit 15 to determine whether the driver is performing manual steering operations while steering control is being executed. The learning value calculation unit 15 determines whether there were manual steering operations by the driver during the execution of steering control, for example, based on whether the steering operation by the driver was detected by the steering sensor of the internal sensor 3 during the execution of steering control. If the learning value calculation unit 15 determines that there were manual steering operations by the driver during the execution of steering control (S03: YES), the ECU 10 interrupts the steering control and proceeds to S04.

[0053] In S04, the ECU 10 calculates the amount of deviation from the target lateral position using the learning value calculation unit 15. The learning value calculation unit 15 calculates the amount of deviation 23 by, for example, determining the distance between the center position 21 and the target path 22 in the vehicle width direction.

[0054] In S05, the ECU 10 uses a learning value calculation unit 15 to determine whether the vehicle 20 is traveling on a straight road. The learning value calculation unit 15 determines whether the vehicle 20 is traveling on a straight road based, for example, on an image of the area in front of the vehicle 20. The learning value calculation unit 15 may also determine whether the vehicle 20 is traveling on a straight road based on the vehicle 20's position on a map and map information.

[0055] If the learning value calculation unit 15 determines that vehicle 20 is traveling on a straight road (S05: YES), the ECU 10 proceeds to S06. In S06, the learning value calculation unit 15 calculates the first learning value. The learning value calculation unit 15 calculates the first learning value, which is the learning value when vehicle 20 is traveling on a straight road, by multiplying the calculated deviation amount 23 by a predetermined proportionality coefficient and adding it to the previous value of the first learning value. In S09, the learning value calculation unit 15 stores the learning value. The learning value calculation unit 15 stores the calculated first learning value as the learning value. After that, the ECU 10 terminates the process shown in Figure 3.

[0056] On the other hand, if the learning value calculation unit 15 determines that the vehicle 20 is not traveling on a straight road (S05: NO), the ECU 10 proceeds to S07. In S07, the learning value calculation unit 15 determines whether or not the vehicle 20 is traveling on a curved road. The learning value calculation unit 15 determines whether or not the vehicle 20 is traveling on a curved road, for example, based on the image captured in front of the vehicle 20. The learning value calculation unit 15 may also determine whether or not the vehicle 20 is traveling on a curved road based on the vehicle 20's position on the map and map information.

[0057] If the learning value calculation unit 15 determines that vehicle 20 is traveling on a curved road (S07: YES), the ECU 10 proceeds to S08. In S08, the learning value calculation unit 15 calculates the second learning value. The learning value calculation unit 15 calculates the second learning value, which is the learning value when vehicle 20 is traveling on a curved road, for example, by the process shown in Figure 4 below. In S09, the learning value calculation unit 15 stores the learning value. The learning value calculation unit 15 stores the calculated second learning value as the learning value. After that, the ECU 10 terminates the process shown in Figure 3.

[0058] On the other hand, if the learning value calculation unit 15 determines that there is no manual steering operation by the driver while steering control is being performed (S03: NO), the ECU 10 performs steering control and terminates the process shown in Figure 3. After the learning shown in Figure 3 has been performed, the ECU 10 may restart steering control with the vehicle control unit 16. For example, if a driver who was performing manual steering operation while steering control was being performed terminates the manual steering operation, the vehicle control unit 16 performs steering control based on the stored learning value and target path.

[0059] Figure 4 is a flowchart showing an example of the calculation process for the second learned value in Figure 3. In S11, the ECU 10 uses the learned value calculation unit 15 to determine whether or not the vehicle 20 is traveling on a right-hand curve. The learned value calculation unit 15 determines whether or not the vehicle 20 is traveling on a right-hand curve based, for example, on an image captured in front of the vehicle 20. The learned value calculation unit 15 may also determine whether or not the vehicle 20 is traveling on a right-hand curve based on the vehicle 20's position on a map and map information.

[0060] If the learning value calculation unit 15 determines that vehicle 20 is traveling on a right-hand curve (S11: YES), the ECU 10 proceeds to S12. In S12, the learning value calculation unit 15 calculates the right-hand learning value as the second learning value. The learning value calculation unit 15 calculates the right-hand learning value, which is the second learning value when vehicle 20 is traveling on a right-hand curve, by multiplying the calculated deviation amount 23 by a predetermined proportionality coefficient and adding it to the previous value of the second learning value. After that, the ECU 10 finishes the process shown in Figure 4 and returns to the process shown in Figure 3.

[0061] On the other hand, if the learning value calculation unit 15 determines that vehicle 20 is not traveling on a right-hand curve (i.e., vehicle 20 is traveling on a left-hand curve) (S11: NO), the ECU 10 proceeds to S13. In S13, the learning value calculation unit 15 calculates the left-hand learning value as the second learning value. The learning value calculation unit 15 calculates the left-hand learning value, which is the second learning value when vehicle 20 is traveling on a left-hand curve, by multiplying the calculated deviation amount 23 by a predetermined proportionality coefficient and adding it to the previous value of the second learning value. After that, the ECU 10 finishes the process shown in Figure 4 and returns to the process shown in Figure 3.

[0062] Figure 5 is a flowchart showing an example of the learning speed setting process. The process shown in Figure 5 may be repeated at a predetermined cycle in parallel with the process in Figure 3, for example, while steering control including steering assistance or automatic steering of the vehicle 20 is being performed.

[0063] In S21, the ECU 10 uses a learning value calculation unit 15 to determine whether the vehicle 20 is traveling on a straight road. The learning value calculation unit 15 determines whether the vehicle 20 is traveling on a straight road, for example, based on an image of the area in front of the vehicle 20. The learning value calculation unit 15 may also determine whether the vehicle 20 is traveling on a straight road based on the vehicle 20's position on a map and map information.

[0064] If the learning value calculation unit 15 determines that vehicle 20 is traveling on a straight road (S21: YES), the ECU 10 proceeds to S22. In S22, the learning value calculation unit 15 sets the learning value calculation speed to the first learning speed. The learning value calculation unit 15 sets the learning value calculation speed to the first learning speed by, for example, setting a predetermined cycle for repeatedly executing the process shown in Figure 3 as the first cycle. After that, the ECU 10 terminates the process shown in Figure 5.

[0065] On the other hand, if the learning value calculation unit 15 determines that vehicle 20 is not traveling on a straight road (i.e., vehicle 20 is traveling on a curved road) (S21: NO), the ECU 10 proceeds to S23. In S23, the learning value calculation unit 15 sets the learning value calculation speed to the second learning speed. The learning value calculation unit 15 sets the learning value calculation speed to the second learning speed by, for example, setting a predetermined cycle for repeatedly executing the process in Figure 3 to the second cycle. After that, the ECU 10 terminates the process in Figure 5.

[0066] According to the steering control device 100 described above, a first learning value for straight roads and a second learning value for curved roads are calculated as learning values ​​for correcting the target lateral position. Here, the amount of deviation 23, which is the error in the lateral position of the vehicle 20 on the road 30 on which the vehicle 20 travels, may be caused by a deviation in the mounting posture of the camera that acquires the captured image. The amount of deviation 23 caused by the deviation in mounting posture is not necessarily uniform, and may be larger on curved roads than on straight roads, for example. According to the above configuration, the first learning value for straight roads and the second learning value for curved roads can be calculated as different values ​​from each other. Therefore, it is possible to calculate a learning value for correcting the target lateral position according to the magnitude of the influence of the deviation in mounting posture on the error in the lateral position of the vehicle.

[0067] In the steering control device 100, the learning value calculation unit 15 calculates a right learning value, which is the second learning value when the vehicle 20 is traveling on a right-hand curve, and a left learning value, which is the second learning value when the vehicle 20 is traveling on a left-hand curve. As a result, the effect of the mounting posture deviation on the error in the vehicle's lateral position is not necessarily the same when the vehicle 20 is traveling on a right-hand curve and when the vehicle 20 is traveling on a left-hand curve. With the above configuration, the right learning value for right-hand curves and the left learning value for left-hand curves can be calculated as different values ​​from each other. Therefore, the second learning values ​​can be calculated to correspond to the difference in the magnitude of the effect on the error in the vehicle's lateral position caused by the mounting posture deviation between right-hand curves and left-hand curves.

[0068] In the steering control device 100, the learning value calculation unit 15 calculates the learning values ​​such that the learning speed of the second learning value is faster than the learning speed of the first learning value. By making the learning speed when driving on a curved road faster than the learning speed when driving on a straight road, the vehicle's lateral position can be corrected earlier on curved roads, where the impact on the error of the vehicle's lateral position tends to be greater.

[0069] [Differentiation] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above. The present invention can be implemented in various forms, starting with the embodiments described above, by making various changes and improvements based on the knowledge of those skilled in the art.

[0070] In the above embodiment, the learning value calculation unit 15 calculated a right learning value, which is the second learning value when the vehicle 20 is traveling on a right curve, and a left learning value, which is the second learning value when the vehicle 20 is traveling on a left curve. However, this example is not essential. The second learning value may be a common learning value for both the right curve and the left curve. The learning value calculation unit 15 only needs to separately calculate at least a first learning value, which is the learning value when the vehicle 20 is traveling on a straight road, and a second learning value, which is the learning value when the vehicle 20 is traveling on a curved road.

[0071] In the above embodiment, the learning value calculation unit 15 calculated the learning values ​​such that the learning speed of the second learning value was faster than the learning speed of the first learning value, but this example is not essential. The learning value calculation unit 15 may calculate the first learning value and the second learning value at the same learning speed.

[0072] In the above embodiment, the vehicle 20 was configured to perform autonomous driving, but this example is not essential. The steering control device 100 may be configured to perform steering control, including steering assistance or automatic steering, in a vehicle 20 that is not configured to perform autonomous driving. In this case, configurations for performing autonomous driving that are not used for steering control, including steering assistance or automatic steering (such as the GPS receiver 1 and the map database 4) may be omitted. [Explanation of Symbols]

[0073] 14...Path generation unit, 15...Learned value calculation unit, 16...Vehicle control unit (steering control unit), 20...Vehicle, 22...Target path, 23...Deviation amount, 100...Steering control device.

Claims

1. A steering control device that performs steering control including steering assistance or automatic steering of a vehicle, A path generation unit generates a target path including a target lateral position within the vehicle's driving lane based on an image captured from the front of the vehicle. When the driver of the vehicle is performing manual steering operations while the steering control is being executed, a learning value calculation unit calculates a learning value to correct the target lateral position based on the amount of deviation from the target lateral position that the manual path of the vehicle following the manual steering operation has relative to the target path, The system includes a steering control unit that performs steering control based on the target path and the learned value, The learning value calculation unit calculates a first learning value, which is the learning value when the vehicle is traveling on a straight road, and a second learning value, which is the learning value when the vehicle is traveling on a curved road. Steering control device.

2. The steering control device according to claim 1, wherein the learning value calculation unit calculates a right learning value, which is the second learning value when the vehicle is traveling on a right curve, and a left learning value, which is the second learning value when the vehicle is traveling on a left curve.

3. The steering control device according to claim 1 or 2, wherein the learning value calculation unit calculates the learning value such that the learning speed of the second learning value is faster than the learning speed of the first learning value.

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