JP2018203156A - Vehicular steering device and vehicle steering control method - Google Patents

Abstract

To provide a vehicular steering device which can achieve improvement of a safety and reduction of discomfort given to a driver.SOLUTION: A steering device 10 comprises: a travel path recognition part 11 which recognizes a travel path of a vehicle 1; a target travel line setting part 12 which sets a target travel line of the vehicle 1 onto the travel path; a steering control amount calculation part 13 which calculates a steering control amount for travelling the vehicle 1 as to follow the target travel line; a relative state amount acquisition part 14 which acquires a relative state amount of the vehicle 1 to the target travel line; a steering control amount restriction part 15 which adds a restriction to the steering control amount based on the relative state amount; and a steering control part 16 which performs a steering control based on the steering control amount. The steering control amount restriction part 15 adds a restriction to a magnitude of a steering control amount to any one of left and right according to positive and negative of the relative state amount.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steering device for assisting steering of steered wheels of a vehicle.

  2. Description of the Related Art Conventionally, techniques for performing steering assistance and automatic steering of steered wheels of vehicles are known. For example, Patent Literature 1 discloses a steering device that sets a target travel line on a travel path (lane) of a vehicle and steers steered wheels so that the vehicle travels following the target travel line.

  On the other hand, Patent Document 2 proposes a technique for preventing the steering feeling of the driver from being deteriorated by the steering assist torque generated by the steering device when the accuracy of the recognition result of the traveling path is lowered. .

Japanese Patent Laid-Open No. 2006-193678 JP 2009-202673 A

  In the technique of Patent Document 2, when the accuracy of the recognition result of the white line (running road boundary line) obtained by the image recognition process decreases, the white line recognition result estimated from the vehicle information (vehicle speed, yaw rate, acceleration, steering angle, etc.) Is used to correct the white line recognition result by the image recognition process and generate the steering assist torque based on the corrected white line recognition result, thereby preventing the driver's steering feeling from deteriorating. In this technique, since the correction accuracy of the white line recognition result depends on the accuracy of the vehicle information, for example, when the vehicle does not travel along the traveling path such as meandering in the traveling path, or the detection accuracy of the vehicle information is low. In this case, there is a possibility that deterioration of steering feeling cannot be appropriately reduced.

  The present invention has been made in order to solve the above-described problems. When a sensor misrecognizes a traveling road, or when a sensor is not dispersed or sensor failure, the traveling road is recognized or vehicle information is detected accurately. Even if the target travel line and the steering control amount are not set appropriately due to the influence of the above, etc., a vehicle steering device that can suppress the assist in the departure direction and can reduce the sense of incongruity to the driver and safety. The purpose is to provide.

  The vehicle steering apparatus according to the present invention includes a travel path recognition unit that recognizes a travel path of a vehicle, a target travel line setting unit that sets a target travel line of the vehicle on the travel path, and the target travel line. A steering control amount calculation unit that calculates a steering control amount for traveling following the vehicle, a relative state amount acquisition unit that acquires a relative state amount of the vehicle with respect to the target travel line, and the relative state amount based on the relative state amount A steering control amount limiting unit that limits the steering control amount; and a steering control unit that performs steering control based on the steering control amount, wherein the steering control amount limiting unit is configured according to whether the relative state amount is positive or negative. Limit the size of the steering control amount to either the left or right.

  According to the vehicle steering apparatus of the present invention, even when the target travel line and the steering control amount are not set appropriately, assist in the departure direction is prevented, or the steering control amount becomes excessively large and the driver It is possible to suppress an uncomfortable feeling in the steering feeling of the vehicle, and to improve the safety and reduce the uncomfortable feeling given to the driving operation of the driver.

1 is a diagram schematically showing a configuration of a vehicle steering system including a vehicle steering apparatus according to Embodiment 1. FIG. 1 is a functional block diagram of a vehicle steering apparatus according to Embodiment 1. FIG. 6 is a flowchart illustrating an operation example 1 of the steering control amount restriction unit according to the first embodiment. 6 is a flowchart illustrating an operation example 2 of the steering control amount restriction unit according to the first embodiment. 6 is a flowchart illustrating an operation example 3 of the steering control amount restriction unit according to the first embodiment. FIG. 3 is a diagram illustrating an example of a hardware configuration of the vehicle steering apparatus according to the first embodiment. FIG. 6 is a functional block diagram of a vehicle steering apparatus according to a second embodiment. 6 is a flowchart showing an operation example 1 of the steering control amount restriction unit according to the second embodiment. 10 is a flowchart showing an operation example 2 of the steering control amount restriction unit in the second embodiment.

  Hereinafter, a vehicle steering apparatus according to the present invention will be described with reference to the drawings according to each embodiment. In each embodiment, the same or corresponding elements are denoted by the same reference numerals, and redundant description is omitted.

<Embodiment 1>
FIG. 1 is a diagram schematically showing a configuration of a vehicle steering system including a vehicle steering apparatus according to a first embodiment. The vehicle steering system is mounted on a vehicle 1 and includes a handle 2, a motor 3, a steering device 4, a camera 5, and a vehicle steering device 10 (hereinafter simply referred to as a “steering device 10”).

  The handle 2 is an operation means for the driver to manually steer the vehicle 1. The steering device 4 steers the front wheels 6 that are steered wheels of the vehicle 1 according to the operation of the handle 2 by the driver. Here, the rear wheel 7 of the vehicle 1 is not a steered wheel, but the present invention can also be applied to a four-wheel steered vehicle 1.

  The motor 3 is connected to the steering device 4 and can apply torque to the steering device 4 in the same manner as a general electric power steering device. The camera 5 captures a front image (front image) viewed from the vehicle 1. The installation position of the camera 5 is, for example, in the vicinity of a room mirror inside the vehicle 1.

  The steering device 10 analyzes the front image of the vehicle 1 captured by the camera 5 and controls the motor 3 based on the analysis result to assist the steering of the vehicle 1. The steering device 10 may have a function of a general electric power steering device in addition to the steering assist function. In FIG. 1, the camera 5 and the steering device 10 are illustrated as separate blocks, but the steering device 10 may be configured as one device including the camera 5.

  FIG. 2 is a functional block diagram of the steering device 10. As shown in FIG. 2, the steering device 10 includes a travel path recognition unit 11, a target travel line setting unit 12, a steering control amount calculation unit 13, a relative state quantity acquisition unit 14, a steering control amount restriction unit 15, and a steering control unit 16. I have.

  The travel path recognition unit 11 recognizes the travel path of the vehicle 1 and the position of the vehicle 1 in the travel path by analyzing the front image of the vehicle 1 captured by the camera 5. The target travel line setting unit 12 sets a target travel line, which is a virtual line representing a track on which the vehicle 1 should travel, on the travel path based on the travel path information recognized by the travel path recognition unit 11. For example, a position away from the right end of the travel path by ½ of the travel path width may be set as the target travel line setting position.

  The steering control amount calculation unit 13 calculates the steering control amount of the vehicle 1 so that the vehicle 1 travels following the target travel line set by the target travel line setting unit 12. For example, the steering control amount calculation unit 13 calculates, as the steering control amount, the steering angle of the vehicle 1 such that the deviation between the position of the vehicle 1 ahead of the predetermined distance and the target travel line approaches zero.

  The relative state quantity acquisition unit 14 acquires the relative state quantity of the vehicle 1 with respect to the target travel line set by the target travel line setting unit 12, and outputs a sign indicating the sign of the relative state quantity. In the present embodiment, the relative state quantity acquired by the relative state quantity acquisition unit 14 includes the lateral deviation of the current position of the vehicle 1 with respect to the target travel line (hereinafter referred to as “lateral deviation”) and the vehicle 1 with respect to the target travel line. At least one of the horizontal speeds (hereinafter referred to as “lateral speeds”).

  The steering control amount limiting unit 15 limits the steering control amount calculated by the steering control amount calculation unit 13 based on the sign (positive / negative) of the relative state amount of the vehicle 1 output by the relative state amount acquisition unit 14. Specifically, the steering control amount limiting unit 15 determines whether or not to limit the steering control amount based on the sign of the relative state amount, and determines that the steering control amount is to be limited. The amount calculation unit 13 is instructed to limit the amount of steering control. When the steering control amount calculation unit 13 receives a steering control amount restriction instruction from the steering control amount restriction unit 15, the steering control amount calculation unit 13 restricts the calculated steering control amount value. The steering control amount restriction instruction input from the steering control amount restriction unit 15 to the steering control amount calculation unit 13 includes at least information indicating the direction in which the restriction is applied. In addition, information indicating the degree of restriction (for example, an upper limit value provided for the steering control amount) may be included in the steering control amount restriction instruction.

  The steering control unit 16 is based on the steering control amount calculated by the steering control amount calculation unit 13 (or the limited steering control amount when the steering control amount calculation unit 13 receives a steering control amount restriction instruction). The torque generated in the motor 3 is controlled. That is, the steering control unit 16 controls the target current that is a control signal of the motor 3 so that torque for realizing the steering control amount calculated by the steering control amount calculation unit 13 is output from the motor 3.

  In addition, the calculation method of the travel route information in the travel route recognition unit 11, the calculation method of the target travel line in the target travel line setting unit 12, the calculation method of the steering control amount in the steering control amount calculation unit 13, and the relative state quantity acquisition unit The calculation method of the relative state quantity in 14 may be any method, for example, a known method disclosed in Patent Document 1 may be used.

  In the steering apparatus 10 according to the first embodiment, the steering control amount restriction unit 15 restricts the steering control amount based on the sign (positive / negative) of the relative state amount of the vehicle 1 with respect to the target travel line. As a result, for example, when the travel path recognition unit 11 erroneously recognizes the travel path, sensor failure, variation, etc., it is possible to prevent the assist in the departure direction and improve safety, or the amount of steering control can be reduced. It can be prevented from becoming excessively large, and the driver's steering feeling can be kept small.

  Hereinafter, some specific examples of the operation of the steering control amount limiting unit 15 in the present embodiment will be shown.

[Operation Example 1]
FIG. 3 is a flowchart showing the operation of the steering control amount restriction unit 15 when the relative state amount of the vehicle 1 acquired by the relative state amount acquisition unit 14 is the lateral deviation of the vehicle 1 with respect to the target travel line. Here, the lateral deviation to the left of the target travel line is defined as positive, and the lateral deviation to the right of the target travel line is defined as negative. That is, when the vehicle 1 is traveling on the left side of the target travel line, a signal indicating that the lateral deviation is positive is output from the relative state quantity acquisition unit 14, and the vehicle 1 is positioned on the right side of the target travel line. When traveling, a signal indicating that the lateral deviation is negative is output from the relative state quantity acquisition unit 14.

  As shown in FIG. 3, the steering control amount restriction unit 15 acquires information on the sign of the lateral deviation of the vehicle 1 from the relative state amount acquisition unit 14 (step S100). Then, the steering control amount restriction unit 15 checks the sign of the lateral deviation of the vehicle 1 (step S101).

  If the lateral deviation of the vehicle 1 is positive, the steering control amount restriction unit 15 restricts the amount of steering control amount in the left direction to a predetermined value or less (step S102). If the lateral deviation of the vehicle 1 is negative, the steering control amount restriction unit 15 restricts the amount of steering control amount in the right direction to a predetermined value or less (step S103). When the lateral deviation of the vehicle 1 is ± 0, that is, when the vehicle 1 is traveling on the target travel line, the steering control amount limiting unit 15 does not limit the steering control amount (step S104). The steering control amount limiting unit 15 repeatedly executes the above processing while the vehicle 1 is traveling.

  According to the operation of the steering control amount restriction unit 15 shown in FIG. 3, when the vehicle 1 is traveling on the left side of the target travel line, a restriction is applied to the steering control amount that further moves the vehicle 1 to the left. When the vehicle 1 is traveling on the right side of the target travel line, a limit is imposed on the steering control amount that moves the vehicle 1 further to the right. By limiting the amount of steering control in the direction in which the deviation of the vehicle 1 with respect to the target travel line is increased, it is possible to reduce the uncomfortable feeling given to the driver's steering feeling.

[Operation example 2]
FIG. 4 is a flowchart showing the operation of the steering control amount restriction unit 15 when the relative state quantity of the vehicle 1 acquired by the relative state quantity acquisition unit 14 is the lateral speed of the vehicle 1 with respect to the target travel line. Here, left lateral speed is defined as positive with reference to the target travel line, and right lateral speed is defined as negative with respect to the target travel line. That is, when the vehicle 1 is moving to the left with respect to the target travel line, a signal indicating that the lateral speed is positive is output from the relative state quantity acquisition unit 14, and the vehicle 1 is based on the target travel line. When moving rightward, a signal indicating that the lateral velocity is negative is output from the relative state quantity acquisition unit 14.

  As shown in FIG. 4, the steering control amount limiting unit 15 acquires information on the sign of the lateral speed of the vehicle 1 from the relative state amount acquisition unit 14 (step S200). Then, the steering control amount restriction unit 15 confirms the sign of the lateral speed of the vehicle 1 (step S201).

  If the lateral speed of the vehicle 1 is positive, the steering control amount restriction unit 15 restricts the magnitude of the left steering control amount to a predetermined value or less (step S202). If the lateral speed of the vehicle 1 is negative, the steering control amount restriction unit 15 restricts the magnitude of the rightward steering control amount to a predetermined value or less (step S203). When the lateral speed of the vehicle 1 is ± 0, that is, when the vehicle 1 is traveling parallel to the target travel line, the steering control amount restriction unit 15 does not restrict the steering control amount (step S204). The steering control amount limiting unit 15 repeatedly executes the above processing while the vehicle 1 is traveling.

  According to the operation of the steering control amount restriction unit 15 shown in FIG. 4, when the vehicle 1 is moving in the lateral direction with reference to the target travel line, the movement speed (lateral speed) is increased in the direction of increasing. A limit is imposed on the steering control amount. By limiting the amount of steering control in the direction of increasing the lateral speed of the vehicle 1 based on the target travel line, it is possible to reduce a sense of discomfort given to the driver's steering feeling.

[Operation Example 3]
FIG. 5 shows the operation of the steering control amount restriction unit 15 when the relative state quantity of the vehicle 1 acquired by the relative state quantity acquisition unit 14 is both the lateral deviation and the lateral speed of the vehicle 1 with respect to the target travel line. It is a flowchart. As for the sign of the lateral deviation, as in the first operation example, the lateral deviation to the left of the target travel line is defined as positive, and the lateral deviation to the right of the target travel line is defined as negative. As in the case of the operation example 2, the sign of the lateral speed is defined as a positive lateral lateral speed with reference to the target travel line and a negative lateral speed with reference to the target travel line.

  As shown in FIG. 5, the steering control amount limiting unit 15 acquires information on the sign of the lateral deviation and the sign of the lateral speed of the vehicle 1 from the relative state quantity obtaining unit 14 (step S300). Then, the steering control amount restriction unit 15 first checks the sign of the lateral deviation of the vehicle 1 (step S301).

  If the lateral deviation of the vehicle 1 is positive, the steering control amount restriction unit 15 further checks whether the sign of the lateral speed of the vehicle 1 is positive (step S302). At this time, if the sign of the lateral speed of the vehicle 1 is positive, the steering control amount limiting unit 15 limits the magnitude of the left steering control amount to a predetermined value or less (step S303). However, if the sign of the lateral speed of the vehicle 1 is not positive, the steering control amount limiting unit 15 does not limit the steering control amount (step S304).

  On the other hand, if the lateral deviation of the vehicle 1 is negative in step S301, the steering control amount limiting unit 15 further confirms whether the sign of the lateral speed of the vehicle 1 is negative (step S305). At this time, if the sign of the lateral speed of the vehicle 1 is negative, the steering control amount restriction unit 15 restricts the steering control amount in the right direction to a predetermined value or less (step S306). However, if the sign of the lateral speed of the vehicle 1 is not negative, the steering control amount restriction unit 15 does not restrict the steering control amount (step S304). The steering control amount limiting unit 15 repeatedly executes the above processing while the vehicle 1 is traveling.

  According to the operation of FIG. 5, when the vehicle 1 is moving in the direction away from the target travel line, the steering control amount in the direction of increasing the moving speed (lateral speed) is limited. By limiting the amount of steering control in the direction of accelerating the deviation of the vehicle 1 from the target travel line, it is possible to reduce the uncomfortable feeling given to the driver's steering feeling.

  Thus, in the steering device 10 according to the first embodiment, the steering control amount restriction unit 15 determines the magnitude of the steering control amount in a specific direction based on the sign of the relative state amount of the vehicle 1 with respect to the target travel line. Limit. Thereby, for example, even when an appropriate target travel line or an appropriate steering control amount cannot be set due to a decrease in travel path recognition accuracy or vehicle information detection accuracy, the steering control is performed so that the vehicle 1 greatly deviates from the target travel line. As a result, safety can be improved and the uncomfortable feeling given to the driver's steering feeling can be reduced.

  In the first embodiment, the camera 5 is used as means for acquiring information for the travel path recognition unit 11 to recognize the travel path. However, any means other than the camera 5 may be used. For example, instead of the camera 5, a positioning device that receives a positioning signal from a GNSS (Global Navigation Satellite System) satellite such as a GPS (Global Positioning System) satellite and calculates the current position of the vehicle 1 is used. The travel path of the vehicle 1 may be recognized from the current position of the vehicle 1 and the map information. In this case, for example, in a place where it is difficult to receive a positioning signal from a GNSS satellite such as under a tunnel or an overhead, the recognition accuracy of the travel path is lowered, and there is a possibility that an appropriate target travel line cannot be set. Is effective.

  In addition, another vehicle (preceding vehicle) traveling in front of the vehicle 1 may be detected using the camera 5 or the radar, and the traveling path may be recognized from the traveling locus of the preceding vehicle. In this case, for example, if it becomes difficult to recognize the preceding vehicle due to the influence of the rain or the side wall of the shoulder of the road, the recognition accuracy of the traveling road is lowered, and there is a possibility that an appropriate target traveling line cannot be set. is there.

  In the first embodiment, the relative state quantity of the vehicle 1 acquired by the steering control amount limiting unit 15 is set to at least one of the lateral deviation and the lateral speed of the vehicle 1, but the vehicle 1 based on the target travel line is further used. Lateral acceleration (lateral acceleration) may be applied. By increasing the elements of the relative state quantity, it becomes possible to finely set conditions for restricting the steering control amount, and an improvement in the driver's steering feeling can be expected.

  In the first embodiment, the lateral deviation of the vehicle 1 acquired by the steering control amount restriction unit 15 is the lateral deviation of the current position of the vehicle 1 with respect to the target travel line. It may be a lateral deviation of the position. Here, the predicted position of the vehicle 1 may be a position where the vehicle 1 is predicted to exist after a certain period of time has elapsed from the current time, or is predicted to exist after the vehicle 1 has advanced a certain distance from the current position. It is good also as a position. The predicted position of the vehicle 1 can be calculated based on the lateral deviation of the current position of the vehicle 1 with respect to the target travel line and the relative angle of the traveling direction of the vehicle 1 with respect to the target travel line. Further, the yaw rate of the vehicle 1 may be taken into consideration in order to improve the estimation accuracy of the predicted position of the vehicle 1. The yaw rate of the vehicle 1 may be the output value of the yaw rate sensor or may be estimated from the steering angle by the steering device 4.

  For example, consider a situation where the vehicle 1 is traveling on the right side of the target travel line and the curvature of the traveling path of the vehicle 1 in the right direction increases, that is, the vehicle 1 enters the right curve. In this situation, if the lateral deviation of the vehicle 1 is based on the current position of the vehicle 1, the steering control amount in the right direction is limited. On the other hand, if the lateral deviation of the vehicle 1 is based on the predicted position of the vehicle 1, the steering control amount in the right direction is restricted from being restricted, thereby improving the driver's steering feeling.

  In the first embodiment, the magnitude of the steering control amount in the specific direction is limited according to the sign of the relative state quantity of the vehicle 1, but the amount of change may be limited with respect to the degree of limitation. Good. In this case, it is possible to prevent the steering control amount from rapidly decreasing when a restriction is applied to the steering control amount, or from rapidly increasing when the restriction on the steering control amount is released. The deterioration of the steering feeling can be prevented.

  FIG. 6 is a diagram illustrating an example of a hardware configuration of the steering apparatus 10. In FIG. 6, the steering apparatus 10 includes an interface (i / F) 101, a processor 102, and a memory 103 that are connected to each other via a bus. The interface 101 performs input / output control of signals with external devices such as the camera 5 and the motor 3. The processor 102 executes various processes according to programs stored in the memory 103. In addition to storing the program, the memory 103 may store data used in each process performed by the processor 102, a processing result, and the like.

  Each element of the steering device 10 shown in FIG. 2 (travel path recognition unit 11, target travel line setting unit 12, steering control amount calculation unit 13, relative state quantity acquisition unit 14, steering control amount restriction unit 15 and steering control unit 16 ) Is realized by the processor 102 executing a program stored in the memory 103. That is, in the memory 103, when executed by the processor 102, a process for recognizing the travel path of the vehicle 1, a process for setting a target travel line on which the vehicle should travel on the travel path, and a target travel line for the vehicle 1 are set. A process for calculating a steering control amount for traveling following the vehicle, a process for obtaining a relative state quantity of the vehicle 1 with respect to the target travel line, and a steering control quantity to either the left or right according to the sign of the relative state quantity A program for executing processing for limiting the size of the vehicle and processing for performing steering control based on the steering control amount is stored.

  Further, the steering device 10 may be configured by dedicated hardware. For example, the steering device 10 may be configured by a digital circuit such as an ASIC (Application Specific Integrated Circuit) that executes processing performed by each element of the steering device 10 illustrated in FIG.

  The configuration in which the function of each element of the steering device 10 is realized by either hardware or software has been described above. However, the present invention is not limited to this, and a configuration in which a part of the steering device 10 is realized by dedicated hardware and another part is realized by software or the like may be used. That is, the steering device 10 may be realized by any of hardware, software, or a combination thereof.

<Embodiment 2>
FIG. 7 is a functional block diagram of the steering apparatus 10 according to the second embodiment. The basic configuration of the steering device 10 of the second embodiment is the same as that of the steering device 10 (FIG. 2) of the first embodiment. However, the relative state quantity acquisition unit 14 outputs a signal indicating not only the sign of the relative state quantity of the vehicle 1 but also the absolute value. Further, the steering control amount limiting unit 15 operates to limit the steering control amount calculated by the steering control amount calculation unit 13 according to the sign and absolute value of the relative state amount of the vehicle 1.

  Hereinafter, some specific examples of the operation of the steering control amount limiting unit 15 in the present embodiment will be shown.

[Operation Example 1]
FIG. 8 is a flowchart showing the operation of the steering control amount limiting unit 15 when the steering control amount is not limited when the absolute value of the relative state amount of the vehicle 1 is equal to or less than a predetermined threshold. Here, the relative state quantity of the vehicle 1 acquired by the relative state quantity acquisition unit 14 is the lateral deviation of the vehicle 1 with respect to the target travel line, and the above threshold is 1 m. Further, the lateral deviation to the left of the target travel line is defined as positive, and the lateral deviation to the right of the target travel line is defined as negative.

  As shown in FIG. 8, the steering control amount restriction unit 15 obtains information on the sign of the lateral deviation of the vehicle 1 from the relative state quantity acquisition unit 14 (step S400). Then, the steering control amount restriction unit 15 checks the absolute value of the lateral deviation of the vehicle 1 (step S401).

  If the absolute value of the vehicle 1 is 1 m or less, the steering control amount restriction unit 15 does not restrict the steering control amount (step S402) and returns to step S400.

  On the other hand, if the absolute value of the vehicle 1 is greater than 1 m, the steering control amount limiting unit 15 checks the sign of the lateral deviation of the vehicle 1 (step S403). If the lateral deviation of the vehicle 1 is positive, the steering control amount restriction unit 15 restricts the magnitude of the left steering control amount to a predetermined value or less (step S404). If the lateral deviation of the vehicle 1 is negative, the steering control amount restriction unit 15 restricts the steering control amount in the right direction to a predetermined value or less (step S405).

  According to the operation of the steering control amount restriction unit 15 shown in FIG. 8, when the vehicle 1 is traveling 1 m or more on the left side of the target travel line, a restriction is imposed on the steering control amount that further moves the vehicle 1 to the left. When the vehicle 1 is traveling 1 m or more on the right side of the target travel line, the steering control amount that moves the vehicle 1 further to the right is limited. By limiting the amount of steering control in a direction in which the deviation of the vehicle 1 with respect to the target travel line is increased by 1 m or more, it is possible to reduce discomfort given to the driver's steering feeling.

[Operation example 2]
FIG. 9 is a flowchart showing the operation of the steering control amount limiting unit 15 in the case where the steering control amount in both the left and right directions is limited when the absolute value of the relative state amount of the vehicle 1 is equal to or less than a predetermined threshold value. It is. Here, the relative state quantity of the vehicle 1 acquired by the relative state quantity acquisition unit 14 is the lateral deviation of the vehicle 1 with respect to the target travel line, and the above threshold is 0.2 m. Further, the lateral deviation to the left of the target travel line is defined as positive, and the lateral deviation to the right of the target travel line is defined as negative.

  As shown in FIG. 9, the steering control amount limiting unit 15 acquires information on the sign of the lateral deviation of the vehicle 1 from the relative state amount acquisition unit 14 (step S500). Then, the steering control amount restriction unit 15 checks the absolute value of the lateral deviation of the vehicle 1 (step S501).

  If the absolute value of the vehicle 1 is 0.2 m or less, the steering control amount limiting unit 15 limits the magnitude of the steering control amount in both the left and right directions to a predetermined value or less (step S502), and returns to step S500. .

  On the other hand, if the absolute value of the vehicle 1 is greater than 0.2 m, the steering control amount restriction unit 15 checks the sign of the lateral deviation of the vehicle 1 (step S503). If the lateral deviation of the vehicle 1 is positive, the steering control amount restriction unit 15 restricts the magnitude of the left steering control amount to a predetermined value or less (step S504). If the lateral deviation of the vehicle 1 is negative, the steering control amount restriction unit 15 restricts the steering control amount in the right direction to a predetermined value or less (step S505).

  According to the operation of the steering control amount limiting unit 15 shown in FIG. 9, it is possible to prevent the steering control having a large steering angle from being performed when the vehicle 1 is not separated from the target travel line by 0.2 m or more. In addition, when the vehicle 1 is traveling 0.2 m or more on the left side of the target travel line, a limit is imposed on the steering control amount that further moves the vehicle 1 to the left, and the vehicle 1 is 0.2 m or more of the target travel line. When traveling on the right side, a limit is imposed on the amount of steering control that further moves the vehicle 1 to the right. By limiting the amount of steering control in the direction in which the deviation of the vehicle 1 with respect to the target travel line is increased, it is possible to reduce the uncomfortable feeling given to the driver's steering feeling.

  In addition, when the deviation of the vehicle 1 with respect to the target travel line is small, a restriction is imposed on the steering control amount in both the left and right directions. For example, when the vehicle 1 is traveling slightly to the left of the target travel line, the vehicle 1 is targeted. It is prevented that steering control with a large steering angle in the right direction is performed in order to approach the traveling line, and the uncomfortable feeling given to the driver's steering feeling can be further reduced.

  In the above example, the relative state quantity of the vehicle 1 is the lateral deviation of the vehicle 1, but the relative state quantity of the vehicle 1 is at least one of the lateral deviation and the lateral speed of the vehicle 1 as in the first embodiment. May be included, and the lateral acceleration of the vehicle 1 may be further included.

  Further, the threshold value provided for the absolute value of the relative state quantity of the vehicle 1 may be provided with hysteresis. For example, when the vehicle 1 is separated from the target travel line by 1 m or more, the steering control amount is limited, and thereafter, when the vehicle 1 approaches within 0.5 m from the target travel line, the limitation of the steering control amount is released. Also good. Thus, frequent switching between restriction / non-restriction of the steering control amount is prevented, which can contribute to improvement in steering feeling.

  Further, the steering control amount restriction unit 15 may change the degree of restriction applied to the steering control amount according to the absolute value of the relative state amount of the vehicle 1. For example, the upper limit value provided in the steering control amount may be reduced as the vehicle 1 moves away from the target travel line. In this case, for example, a map indicating the relationship between the relative state quantity of the vehicle 1 and the upper limit value of the steering control amount is stored in the steering control unit 16, and the steering control unit 16 refers to the map to determine the steering control amount. An upper limit value may be set.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

  1 Vehicle, 2 Handle, 3 Motor, 4 Steering Device, 5 Camera, 6 Front Wheel, 7 Rear Wheel, 10 Steering Device, 101 Interface, 102 Processor, 103 Memory, 11 Travel Path Recognition Unit, 12 Target Travel Line Setting Unit, 13 Steering control amount calculation unit, 14 Relative state amount acquisition unit, 15 Steering control amount restriction unit, 16 Steering control unit.

Claims (14)

A travel path recognition unit for recognizing the travel path of the vehicle;
A target travel line setting unit for setting a target travel line of the vehicle on the travel path;
A steering control amount calculation unit that calculates a steering control amount for causing the vehicle to travel following the target travel line;
A relative state quantity acquisition unit for acquiring a relative state quantity of the vehicle with respect to the target travel line;
A steering control amount limiting unit that limits the steering control amount based on the relative state amount;
A steering control unit that performs steering control based on the steering control amount;
With
The steering control amount restriction unit restricts the magnitude of the steering control amount to either the left or right according to the sign of the relative state amount.
Vehicle steering system. The steering control amount restriction unit further restricts the steering control amount in consideration of the absolute value of the relative state amount.
The vehicle steering apparatus according to claim 1. The steering control amount limiting unit does not limit the steering control amount when an absolute value of the relative state amount is equal to or less than a predetermined threshold;
The vehicle steering apparatus according to claim 2. The steering control amount restriction unit restricts the steering control amount in both the left and right directions when the absolute value of the relative state quantity is equal to or less than a predetermined threshold;
The vehicle steering apparatus according to claim 2. The steering control amount restriction unit changes a degree of restriction applied to the steering control amount according to an absolute value of the relative state amount;
The vehicle steering apparatus according to claim 2. The relative state quantity is at least one of a lateral deviation and a lateral speed of the vehicle with respect to the target travel line.
The vehicle steering apparatus according to any one of claims 1 to 5. The relative state quantity further includes a lateral acceleration of the vehicle with respect to the target travel line.
The vehicle steering apparatus according to claim 6. The lateral deviation of the vehicle is a lateral deviation of the current position of the vehicle with respect to the target travel line.
The vehicle steering apparatus according to claim 6 or 7. The lateral deviation of the vehicle is a lateral deviation of the predicted position of the vehicle with respect to the target travel line.
The vehicle steering apparatus according to claim 6 or 7. The predicted position of the vehicle is a position where the vehicle is predicted to exist after a certain time has elapsed from the current time.
The vehicle steering apparatus according to claim 9. The predicted position of the vehicle is a position where the vehicle is predicted to exist after the vehicle has traveled a certain distance from the current position.
The vehicle steering apparatus according to claim 9. The predicted position of the vehicle is calculated based on a lateral deviation of the current position of the vehicle with respect to the target travel line and a relative angle of the vehicle with respect to the target travel line.
The vehicle steering apparatus according to any one of claims 9 to 11. The predicted position of the vehicle is calculated based on a lateral deviation of the current position of the vehicle with respect to the target travel line, a relative angle of the vehicle with respect to the target travel line, and a yaw rate of the vehicle.
The vehicle steering apparatus according to any one of claims 9 to 11. A vehicle steering control method in a vehicle steering apparatus,
The travel path recognition unit of the vehicle steering device recognizes the travel path of the vehicle,
A target travel line setting unit of the vehicle steering device sets a target travel line of the vehicle on the travel path;
A steering control amount calculation unit of the vehicle steering device calculates a steering control amount for causing the vehicle to travel following the target travel line;
A relative state quantity acquisition unit of the vehicle steering device acquires a relative state quantity of the vehicle with respect to the target travel line;
The steering control amount limiting unit of the vehicle steering device adds a limit to the size of the steering control amount to either the left or right according to the sign of the relative state amount,
A steering control unit of the vehicle steering device performs steering control based on the steering control amount;
Vehicle steering control method.

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