JP6419671B2 - Vehicle steering apparatus and vehicle steering method - Google Patents

Description

  The present invention relates to a vehicle steering apparatus and a vehicle steering method for controlling steered wheels of a vehicle.

  In a conventional vehicle steering apparatus having a lane keeping assist function (see, for example, Patent Document 1), a target travel line is automatically set by various methods, and the vehicle follows the set target travel line. It is comprised so that steering assistance may be performed so that it may drive | work.

JP 2001-001921 A

  Here, there is a possibility that the target travel line automatically set by the vehicle steering device is different from the travel line actually preferred by the driver. For example, when a driver of a vehicle travels in a travel lane, which of the travel positions of the center, right side, and left side of the travel lane tends to change according to the characteristics of the driver. Moreover, even if it is the same driver | operator, there exists a tendency for the preference of a driving | running | working position to differ according to the driving | running | working environment where a vehicle drive | works.

  Therefore, when steering assistance is performed so that the vehicle travels following the target travel line regardless of the driver's preference as in a conventional vehicle steering device, the vehicle at the travel position desired by the driver is reduced. There is a possibility that the driving cannot be continued, and as a result, the driver may feel uncomfortable.

  In addition, when the driver steers the vehicle at the travel position desired by the driver at the timing when the steering assist by the vehicle steering device is performed, the steering assist by the vehicle steering device This may conflict with the steering by the driver, and as a result, traveling stability may be reduced.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle steering apparatus and a vehicle steering method capable of controlling steered wheels in consideration of the driver's preference. And

The vehicle steering apparatus according to the present invention includes a travel path recognition unit that generates front travel path information by recognizing a travel path on which the vehicle travels, and a target when the vehicle travels following the travel path from the forward travel path information. A target travel line setting unit that sets a target travel line, a lateral travel calculation unit that calculates a lateral displacement corresponding to the forward gaze distance of the vehicle, and a travel of the vehicle Based on the running state quantity detection unit that detects the state quantity and the running state quantity, it is determined whether or not the vehicle is traveling on the driving line preferred by the driver, and the lateral displacement learning value is calculated from the lateral displacement according to the determination result. calculated, based on the deviation between the lateral displacement and lateral displacement learned value and the lateral displacement correction value calculating unit for calculating a lateral displacement correction value, the lateral speed, which is the rate of change of lateral displacement as lateral displacement correction value decreases , the target steering angle calculating for calculating a target steering angle If, from the target steering angle, in which and a steering control unit that controls the steering angle of the vehicle.

The vehicle steering method according to the present invention includes a travel path recognition step for generating a forward travel path information by recognizing a travel path on which the vehicle travels, and when the vehicle travels following the travel path from the forward travel path information. A target travel line setting step for setting a target travel line to be a target of the vehicle, a lateral displacement calculation step for calculating a lateral displacement corresponding to the forward gaze distance of the vehicle from the forward travel path information and the target travel line, a vehicle From the driving state quantity detecting step for detecting the driving state quantity and the driving state quantity, it is determined whether or not the vehicle is traveling on the driving line preferred by the driver, and the lateral displacement is learned from the lateral displacement according to the determination result. It calculates a value, a deviation between the lateral displacement and lateral displacement learned value and the lateral displacement correction value calculating step of calculating a lateral displacement correction value, the lateral speed, which is the rate of change of lateral displacement as lateral displacement correction value decreases Base Te, a target steering angle calculating step of calculating a target steering angle, the target steering angle is obtained by including a steering control step of controlling the steering angle of the vehicle, a.

  According to the present invention, it is determined whether or not the vehicle is traveling on a travel line preferred by the driver from the travel state quantity of the vehicle, and the lateral displacement learning value is calculated according to the determination result, and the lateral displacement and the lateral displacement are calculated. The target rudder angle is calculated by controlling the lateral speed, which is the changing speed of the lateral displacement, so that the lateral displacement correction value corresponding to the deviation from the displacement learning value decreases. Thereby, the vehicle steering device and the vehicle steering method that can control the steered wheels in consideration of the driver's preference can be obtained.

1 is a configuration diagram showing a vehicle steering apparatus in Embodiment 1 of the present invention. It is a block diagram which shows roughly an example of the hardware constitutions of the control unit of FIG. It is a functional block diagram which shows the structure of the control unit of FIG. It is explanatory drawing for demonstrating the front travel path information produced | generated by the travel path recognition part of FIG. It is a figure which shows the two-wheel model of the steering apparatus for vehicles in Embodiment 1 of this invention. It is a figure which shows the relationship between the vehicle fixed coordinate system and the ground fixed coordinate system for demonstrating the steering apparatus for vehicles in Embodiment 1 of this invention. It is a flowchart which shows a series of operation | movement of the steering apparatus for vehicles in Embodiment 1 of this invention. It is a flowchart which shows a series of processes of the lateral displacement correction value calculation process performed by the lateral displacement correction value calculation part of FIG. It is a flowchart which shows a series of processes of the target rudder angle calculation process performed by the target rudder angle calculation part of FIG.

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

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing a vehicle steering apparatus according to Embodiment 1 of the present invention. The vehicle steering apparatus shown in FIG. 1 is applied to a vehicle 1 including a handle 2 and a tire 5. 1 includes a motor 3, a steering mechanism 4, a vehicle speed detection unit 6, a yaw rate detection unit 7, a steering torque detection unit 8, a camera 9, and a control unit 10.

  The left and right tires 5 are steered by a steering mechanism 4 connected to the handle 2 of the vehicle 1. A motor 3 is connected to the steering mechanism 4 in the same manner as a general electric power steering apparatus, and torque generated by the motor 3 can be applied to the steering mechanism 4. The motor 3 is driven according to the target current Imtr_tg included in the drive signal input from the control unit 10.

  The vehicle speed detector 6 detects the vehicle speed of the vehicle 1, the yaw rate detector 7 detects the yaw rate of the vehicle 1, and the steering torque detector 8 detects the steering torque of the vehicle 1. The camera 9 is installed in the vicinity of the rearview mirror in the vehicle 1, captures a front image of the vehicle 1 through the windshield of the vehicle 1, and outputs the captured result as front image data.

  The control unit 10 is connected to each of the vehicle speed detection unit 6, the yaw rate detection unit 7, the steering torque detection unit 8, the camera 9, and the motor 3. In addition, detection results from the detection units of the vehicle speed detection unit 6, the yaw rate detection unit 7, and the steering torque detection unit 8 are input to the control unit 10 as detection signals, and forward image data is input from the camera 9. Further, the control unit 10 outputs a drive signal to the motor 3. Note that the control unit 10 may have not only a function of controlling driving of the motor 3 but also a control function of a general electric power steering apparatus.

  FIG. 2 is a block diagram schematically showing an example of the hardware configuration of the control unit 10 of FIG. The control unit 10 includes an interface 101, a processor 102, and a memory 103.

  The interface 101 performs input / output control of signals with external devices such as the vehicle speed detection unit 6, the yaw rate detection unit 7, the steering torque detection unit 8, the camera 9, and the motor 3. The processor 102 executes various processes according to programs stored in the memory 103. The memory 103 further stores data used in each processing, processing results, and the like together with the above-described program. The interface 101, the processor 102, and the memory 103 are connected by a bus.

  FIG. 3 is a functional block diagram showing the configuration of the control unit 10 of FIG. In FIG. 3, the traveling state amount detection unit 26, the traveling environment detection unit 27, and the vehicle state amount detection unit 28 connected to the control unit 10 are illustrated together.

  The control unit 10 includes a travel path recognition unit 21, a target travel line setting unit 22, a lateral displacement calculation unit 23, a lateral displacement correction value calculation unit 24, a target rudder angle calculation unit 25, and a steering control unit 29.

  Here, the processing of each functional block constituting the control unit 10 is executed by the processor 102 in accordance with a program stored in the memory 103 shown in FIG. The hardware configuration of the control unit 10 may be configured by a digital circuit such as an ASIC (Application Specific Integrated Circuit) that performs processing of each functional block instead of the configuration shown in FIG. It doesn't matter.

  The travel path recognition unit 21 recognizes the travel path on which the vehicle 1 travels, thereby generating front travel path information from the front image data input from the camera 9 and outputting the front travel path information.

  Here, generation of forward travel path information by the travel path recognition unit 21 will be described with reference to FIG. FIG. 4 is an explanatory diagram for describing the forward travel path information generated by the travel path recognition unit 21 in FIG. 3. In the following, a vehicle fixed coordinate system is defined, and a forward direction of the vehicle 1 is an x direction, and a lateral direction of the vehicle 1 and a direction perpendicular to the x direction is a y direction. Further, the position of the vehicle center of gravity P0 of the vehicle 1 is defined as the position of the vehicle 1.

  As shown in FIG. 4, the travel path recognition unit 21 applies a known technique from the front image data input from the camera 9 to obtain a lane boundary line line_b such as a white line that exists on both the left and right sides of the travel path. To detect.

  Subsequently, the travel path recognition unit 21 obtains a front gaze position P1 that is separated from the vehicle center of gravity P0, which is the current position of the vehicle 1, by a front gaze distance Ld in the x direction, and a straight line in the y direction passing through the front gaze position P1. A lane boundary line position P2 where the forward gaze reference line and the inside of the lane boundary line line_b intersect is obtained.

  The travel path recognition unit 21 calculates the lane distance yLd_lane corresponding to the front gaze point distance Ld, based on the distance between the front gaze position P1 and the lane boundary line position P2. Further, the travel path recognition unit 21 calculates the curvature of the lane boundary line line_b at the lane boundary line position P2, and based on the curvature, the angle between the tangent line at the lane boundary line position P2 of the lane boundary line line_b and the x direction is Calculated as the lane boundary line inclination angle corresponding to the forward gazing point distance Ld.

  Subsequently, the travel path recognition unit 21 calculates a target travel line inclination angle eLd corresponding to the forward gazing distance Ld from the lane boundary line inclination angle corresponding to the forward gazing distance Ld. Here, as a specific method of calculating the target travel line inclination angle eLd, for example, the following method can be cited.

  That is, when the lane boundary line inclination angle corresponding to the forward gazing distance Ld is calculated for both lane boundary lines line_b, for example, the value is set to one value by processing such as averaging. The travel line inclination angle eLd may be used. On the other hand, when the lane boundary line inclination angle corresponding to the forward gazing distance Ld is calculated on only one of the lane boundary lines line_b on both sides, the value of the lane boundary line inclination angle may be set as the target travel line inclination angle eLd. .

  The travel path recognition unit 21 calculates the travel path width from the detected lane boundary line line_b on both sides. When only one of the lane boundary lines line_b on both sides is detected, the travel path recognition unit 21 calculates a general travel path width value, for example, 3.5 m as the travel path width.

  The travel path recognition unit 21 outputs each position obtained above and each value calculated above as forward travel path information.

  The target travel line setting unit 22 travels the target travel line line_tg as a target when the vehicle 1 travels following the travel path from the front travel path information input from the travel path recognition unit 21 as the target travel line setting process. Set in the road. Further, the target travel line setting unit 22 outputs the set target travel line line_tg.

  For example, the target travel line setting unit 22 sets the target travel line line_tg at a position separated from the right lane boundary line line_b by, for example, a setting distance that is ½ of the travel road width with reference to the right lane boundary line line_b. Set. The set target travel line line_tg has a target travel line inclination angle eLd at the target travel line position P3 on the forward gaze reference line that is a set distance away from the lane boundary line position P2.

  As the lateral displacement calculation process, the lateral displacement calculation unit 23 calculates the forward note of the vehicle 1 from the forward travel path information input from the travel path recognition unit 21 and the target travel line line_tg input from the target travel line setting unit 22. A lateral displacement yLd corresponding to the viewpoint distance Ld is calculated. Further, the lateral displacement calculation unit 23 outputs the calculated lateral displacement yLd. Here, as a specific method for calculating the lateral displacement yLd, for example, the following method can be cited.

  That is, when the right lane boundary line line_b is detected, the lateral displacement calculation unit 23 calculates the lane distance yLd_lane calculated from the forward gaze position P1 and the lane boundary line position P2 on the right lane boundary line line_b. Is the first distance. Further, the lateral displacement calculation unit 23 calculates the distance between the target travel line line_tg and the right lane boundary line line_b as the second distance. Then, the lateral displacement calculation unit 23 sets the value obtained by subtracting the second distance from the first distance as the lateral displacement yLd. In this case, when the vehicle 1 is on the left side with respect to the target travel line line_tg, the lateral displacement yLd has a positive value, and when the vehicle 1 is on the right side, the lateral displacement yLd has a negative value.

  On the other hand, when only the left lane boundary line line_b is detected, the lateral displacement calculation unit 23 calculates the lane distance calculated from the forward gaze position P1 and the lane boundary line position P2 on the left lane boundary line line_b. Let yLd_lane be the third distance. Further, the lateral displacement calculation unit 23 calculates the distance between the target travel line line_tg and the left lane boundary line line_b as the fourth distance. Here, a value obtained by subtracting the third distance from the travel path width corresponds to the first distance. Further, a value obtained by subtracting the fourth distance from the travel path width corresponds to the second distance. Accordingly, the lateral displacement calculation unit 23 sets the value obtained by subtracting the third distance from the fourth distance as the lateral displacement yLd.

  The travel state amount detection unit 26 detects a travel state amount indicating the travel state of the vehicle 1 and outputs the detection result to the lateral displacement correction value calculation unit 24. Specifically, the travel state amount detection unit 26 includes the steering torque detection unit 8 and outputs the steering torque of the vehicle 1 to the lateral displacement correction value calculation unit 24 as the travel state amount of the vehicle 1.

  The travel environment detection unit 27 detects the travel environment of the vehicle 1 and outputs the detection result to the lateral displacement correction value calculation unit 24. Specifically, the travel environment detection unit 27 includes the vehicle speed detection unit 6 and outputs the vehicle speed of the vehicle 1 to the lateral displacement correction value calculation unit 24 as the travel environment of the vehicle 1.

  The lateral displacement correction value calculation unit 24 calculates a lateral displacement learning value yLd_lrn from the lateral displacement yLd input from the lateral displacement calculation unit 23 as a lateral displacement correction value calculation process, and calculates the lateral displacement yLd and the lateral displacement learning value yLd_lrn. The deviation is calculated as a lateral displacement correction value yLd_c.

  Specifically, the lateral displacement correction value calculation unit 24 determines that the vehicle 1 is the driver's driver from the lateral displacement yLd input from the lateral displacement calculation unit 23 and the travel state amount input from the travel state amount detection unit 26. It is determined whether or not the vehicle is traveling on a preferred travel line. The lateral displacement correction value calculation unit 24 calculates a lateral displacement learning value yLd_lrn according to the determination result, and calculates a deviation between the lateral displacement yLd and the lateral displacement learning value yLd_lrn as a lateral displacement correction value yLd_c. Further, the lateral displacement correction value calculation unit 24 outputs the calculated lateral displacement correction value yLd_c.

  The lateral displacement learning value yLd_lrn described above corresponds to the displacement between the target travel line line_tg and the travel line preferred by the driver, corresponding to the forward gaze distance Ld.

  The vehicle state quantity detection unit 28 detects a vehicle state quantity indicating the vehicle state of the vehicle 1 and outputs the detection result to the target rudder angle calculation unit 25. Specifically, the vehicle state quantity detection unit 28 includes a vehicle speed detection unit 6 and a yaw rate detection unit 7, and the target steering angle calculation unit uses the vehicle speed and yaw rate of the vehicle 1 as the vehicle state quantity of the vehicle 1. To 25.

  The target rudder angle calculation unit 25 controls the lateral speed, which is the change speed of the lateral displacement yLd, so that the lateral displacement correction value yLd_c input from the lateral displacement correction value calculation unit 24 decreases as the target rudder angle calculation process. Then, the target rudder angle is calculated.

  Specifically, the target rudder angle calculation unit 25 corrects the lateral displacement from the lateral displacement correction value yLd_c input from the lateral displacement correction value calculation unit 24 and the vehicle state quantity input from the vehicle state quantity detection unit 28. A target steering angle is calculated such that the value yLd_c converges to zero.

  Thus, the target rudder angle calculation unit 25 calculates a target rudder angle for controlling the vehicle 1 to travel along a travel line preferred by the driver. Moreover, the target rudder angle calculation part 25 outputs the calculated target rudder angle.

  The steering control unit 29 controls the steering angle of the vehicle 1 from the target steering angle input from the target steering angle calculation unit 25 as steering control processing. Specifically, the steering control unit 29 calculates a target steering torque from the target steering angle input from the target steering angle calculation unit 25, and outputs a drive signal to the motor 3 so as to realize the target steering torque. . Here, the target steering torque may be obtained as a torque corresponding to the target steering angle using the steering torque characteristic with respect to the steering angle acquired in advance. The drive signal is obtained from the motor characteristics of the motor 3 as the target current Imtr_tg for generating the target steering torque. The steering torque characteristic with respect to the steering angle of the steering mechanism 4 and the motor characteristic of the motor 3 are stored in advance in the storage unit.

  The target steering torque may be calculated by multiplying the deviation between the target rudder angle and the detected rudder angle by a gain such that the deviation converges to zero. There is no limitation on the method for calculating the steering torque.

  Here, when the driver continues to steer so that the vehicle 1 travels on the travel line preferred by the driver instead of the travel line preferred by the driver, the lateral displacement correction value calculation is performed. The lateral displacement learning value yLd_lrn calculated by the unit 24 is a displacement between the target travel line line_tg and the travel line preferred by the driver.

  Therefore, the steering control unit 29 controls the steered wheels according to the target rudder angle calculated by the target rudder angle calculation unit 25, so that the travel line displaced by the lateral displacement learning value yLd_lrn with respect to the target travel line line_tg, that is, Thus, the vehicle 1 can travel along the travel line preferred by the driver.

  Next, the principle by which the target rudder angle calculation unit 25 calculates a target rudder angle that converges the lateral displacement correction value yLd_c to 0 will be described.

  Regarding the calculation of the target rudder angle, the lateral displacement correction value yLd_c converges to 0 so that the displacement between the target travel line line_tg on the forward gaze reference line and the position of the vehicle 1 becomes the lateral displacement learning value yLd_lrn. What is necessary is just to obtain | require an angle as a target rudder angle.

  Here, a lateral speed y′Ld, which is a changing speed of the lateral displacement yLd, is considered with respect to the lateral displacement correction value yLd_c. If the lateral velocity y′Ld is controlled so that the lateral displacement correction value yLd_c decreases, the lateral displacement correction value yLd_c approaches 0. Therefore, if the lateral velocity y′Ld is controlled so as to satisfy the following equation (1), Good.

    y′Ld = −λ · yLd_c (1)

  However, in Equation (1), y′Ld is a lateral velocity at the forward gaze position P1, yLd_c is a lateral displacement correction value, and λ is a yLd attenuation characteristic parameter that takes a positive value. However, it tends to be unstable.

  Here, in order to obtain the lateral velocity y′Ld, an equation of motion of a two-wheel model based on a coordinate system fixed to the vehicle is considered. FIG. 5 is a diagram showing a two-wheel model of the vehicle steering apparatus according to Embodiment 1 of the present invention. The equation of motion of the two-wheel model shown in FIG. 5 is given by the following equation (2).

  Here, m is the vehicle weight, vx0 and vy0 are the vehicle longitudinal speed and the vehicle lateral speed at the vehicle center of gravity, v′y0, the vehicle lateral acceleration at the vehicle center of gravity, γ ′ is the yaw rate, Lf is the center-to-front wheel axle distance, Lr is the distance between the center of gravity and the rear wheel axle, Cf is the front wheel side force stiffness, Cr is the rear wheel side force stiffness, and θ is the steering angle.

  The vehicle lateral speed vy0 and the steering angle θ are positive in the left direction, and the yaw rate γ ′ is positive in the counterclockwise direction. Further, “′” in the equation represents a time change due to differentiation, for example, the differentiation of displacement is speed and the differentiation of speed is acceleration.

On the other hand, if the coordinate components of the vehicle fixed coordinate system of the target travel line position P3 corresponding to the forward gazing point distance Ld and the vehicle gravity center P0 are [x1, y1] ^T and [x0, y0] ^T , respectively, (3) can be expressed as follows.

  Here, a ground fixed coordinate system is considered. FIG. 6 is a diagram showing the relationship between the vehicle fixed coordinate system and the ground fixed coordinate system for explaining the vehicle steering apparatus according to the first embodiment of the present invention. In FIG. 6, the vehicle fixed coordinate system [x, y] is indicated by a broken line, and the ground fixed coordinate system [X, Y] is indicated by a solid line.

  Note that the target travel line line_tg indicated by the one-dot chain line in FIG. 4 extends, for example, along the center of the width of the road. Accordingly, FIG. 4 shows a state where the current vehicle 1 is traveling on the right side of the road (for example, the right lane). Further, the lateral displacement yLd is the distance between the front gaze position P1 and the target travel line position P3 corresponding to the front gaze point distance Ld.

  Since the yaw rate γ ′ of the vehicle 1 is defined as positive in the counterclockwise direction, if the vehicle fixed coordinate system is at a position rotated counterclockwise by δ with respect to the ground fixed coordinate system, The direction of δ is positive. That is, the yaw rate γ 'of the vehicle 1 is positive when the vehicle 1 rotates counterclockwise with respect to the ground.

Therefore, when Expression (3) is converted from the vehicle fixed coordinate system to the ground fixed coordinate system, and the coordinate components of the ground fixed coordinate system are [X1, Y1] ^T and [X0, Y0] ^T , respectively, (4) can be expressed as follows.

Further, regarding the moving speed of the target travel line position P3, when the coordinate component of the vehicle fixed coordinate system is [vx1, vy1] ^T and is expressed by [X1, Y1] ^T of the ground fixed coordinate system, these are expressed by the following formula (5 ).

  In order to substitute the formula (4) into the formula (5), the following formula (6) is obtained by differentiating the formula (4).

When the ground fixed coordinate system [X′0, Y′0] ^T of Expression (6) is represented by the vehicle fixed coordinate system [vx0, vy0] ^T , the following Expression (7) is obtained.

Substituting Equation (6) and Equation (7) into Equation (5), the moving speed [vx1, vy1] ^T of the target travel line position P3 is equal to the yaw rate of the vehicle 1 regardless of the coordinate system. Considering that γ ′, the following expression (8) is expressed in the vehicle fixed coordinate system.

  Further, when the relationship between the target travel line inclination angle eLd and the speed of the target travel line position P3 is expressed in the vehicle fixed coordinate system, the following equation (9) is obtained.

  By substituting Equation (9) into vy1 of the second row of Equation (8) and making the curvature of the vehicle travel path moderate and | eLd | << 1 to tan (eLd) ≈eLd, the target travel line line_tg The lateral velocity y′Ld with respect to is expressed by the following equation (10) in the vehicle fixed coordinate system.

  When substituting equation (10) into equation (2), solving equation (10) with respect to vy0 yields the following equation (11), which is further differentiated and v′x1≈0 is considered as there is no sudden change in vehicle speed Then, the following formula (12) is obtained.

  Expressions (11) and (12) are substituted into Expression (2). Here, if the vertical speed of the vehicle 1 >> the lateral speed and the influence of the yaw rate on the speed of the vehicle 1 are considered to be minute, the speed of the vehicle 1 in the vehicle fixed coordinate system and the ground fixed coordinate system can be regarded as equal. If the change in the vehicle speed is considered to be minute, vx0 = vx1 and the vehicle longitudinal speed in the ground fixed coordinate system can be made constant. Therefore, if the vehicle speed in the fixed ground coordinate system, that is, the vehicle speed detected by the vehicle speed detection unit 6 is V, it can be considered that V = vx0 = vx1, and therefore, it is a two-wheel model based on the front gaze distance Ld. The following formula (13) is obtained.

  When Expression (13) is solved for the lateral velocity y′Ld, the following Expression (14) is obtained.

  Here, since y ″ Ld in the equation (14) is acceleration in the lateral direction of the vehicle, assuming that an extreme side slip angle such as slip does not occur, the state in which y ″ Ld is generated is regarded as the curve running state. Suppose you can. In this case, since y ″ Ld is the acceleration of the circular motion, it can be considered as the following formula (15). Further, by substituting equation (15) into equation (14), some terms in equation (14) can be canceled.

  The differential terms e′Ld and γ ″ are generated only when the curvature changes and the yaw rate changes due to the change in the steering angle in response to entering or leaving the curve. Although there is a timing deviation, the value is in the direction of canceling.

  For this reason, if the terms of e′Ld and γ ″ are omitted together, it is considered that the influence is small, and by omitting these terms, y′Ld is prevented from sudden change, that is, the target rudder angle is finally set. It is possible to simplify the formula. Therefore, when Expression (15) is substituted into Expression (14) and the terms e′Ld and γ ″ are omitted, Expression (14) can be expressed as Expression (16) below.

  Therefore, substituting equation (16) indicating the lateral speed into equation (1), considering θ as the target rudder angle, and organizing with θ, the following equation (17) is obtained.

  Finally, in the equation (17), when the coefficients k1 to k3 are set as the following equations (18) to (20), the following equation (21) is obtained.

    θ = k1 · yLd_c + k2 · eLd−k3 · γ ′ (21)

  In equation (21), θ is a target steering angle, k1 to k3 are coefficients, yLd_c is a lateral displacement correction value, eLd is a target travel line inclination angle, and γ ′ is a yaw rate.

  Thus, the target rudder angle calculation unit 25 makes the target rudder angle such that the lateral displacement correction value yLd_c converges to 0 from the yaw rate included in the vehicle state quantity and the target travel line inclination angle eLd included in the forward travel path information. Can be calculated.

  Next, the operation of the vehicle steering apparatus according to the first embodiment will be described with reference to FIG. FIG. 7 is a flowchart showing a series of operations of the vehicle steering apparatus according to Embodiment 1 of the present invention. Note that the processing of the flowchart of FIG. 7 is executed at a preset constant period, for example, every 0.01 seconds.

  In FIG. 6, first, in step S101, the target travel line setting unit 22 sets the target travel line line_tg by executing the target travel line setting process, and proceeds to step S102.

  In step S102, the lateral displacement calculation unit 23 calculates lateral displacement yLd by executing a lateral displacement calculation process, and proceeds to step S103.

  In step S103, the lateral displacement correction value calculation unit 24 calculates a lateral displacement correction value yLd_c by executing a lateral displacement correction value calculation process, and proceeds to step S104. Details of the lateral displacement correction value calculation process will be described later.

  In step S104, the target rudder angle calculation unit 25 calculates the target rudder angle ang_tg by executing the target rudder angle calculation process, and proceeds to step S105. Details of the target rudder angle calculation process will be described later.

  Finally, in step S105, the steering control unit 29 executes a steering control process to output a drive signal to the motor 3, and ends a series of processes.

  Next, details of the lateral displacement correction value calculation processing by the lateral displacement correction value calculation unit 24 in step S103 will be described with reference to FIG. FIG. 8 is a flowchart showing a series of processes of the lateral displacement correction value calculation process executed by the lateral displacement correction value calculation unit 24 of FIG.

  In step S201, the lateral displacement correction value calculation unit 24 executes lateral displacement learning storage value update determination, and proceeds to step S202 or S204 according to the execution result.

  Specifically, the lateral displacement correction value calculation unit 24 selects a travel line preferred by the driver from the lateral displacement yLd input from the lateral displacement calculation unit 23 and the steering torque input from the travel state amount detection unit 26. It is determined whether or not the vehicle 1 is traveling.

  When the lateral displacement correction value calculation unit 24 determines that the vehicle 1 is traveling on the travel line preferred by the driver, the lateral displacement correction value calculation unit 24 outputs “1” as the lateral displacement learning storage value update flag, and the process proceeds to step S202. move on.

  On the other hand, if the lateral displacement correction value calculation unit 24 determines that the vehicle 1 is not traveling on the travel line preferred by the driver, the lateral displacement correction value calculation unit 24 outputs “0” as the lateral displacement learning stored value update flag, and step S204. Proceed to

  The lateral displacement learning storage value update flag indicates the contents of the lateral displacement learning value determination process in step S204, which will be described later, by binary values "0" and "1". When the lateral displacement learning value update flag is “1”, this indicates that the lateral displacement learning stored value stored in the storage unit is updated in the lateral displacement learning value determination process. On the other hand, when the lateral displacement learning memory value update flag is “0”, it indicates that the lateral displacement learning memory value stored in the storage unit is not updated in the lateral displacement learning value determination process.

  As described above, when the lateral displacement correction value calculation unit 24 determines that the vehicle 1 is traveling on the travel line preferred by the driver, the lateral displacement correction value calculation unit 24 updates the lateral displacement learning storage value stored in the storage unit. Therefore, “1” is output as the lateral displacement learning stored value update flag. On the other hand, when the lateral displacement correction value calculation unit 24 determines that the vehicle 1 is not traveling on the travel line preferred by the driver, the lateral displacement learning storage value is stored so as not to update the lateral displacement learning memory value. “0” is output as the value update flag.

  Moreover, the following method is mentioned as a specific example of the determination method which determines whether the vehicle 1 is drive | working the driving | running | working line which a driver | operator likes from lateral displacement yLd and steering torque.

  That is, a period in which the absolute value of the steering torque is within a setting range larger than the steering torque setting value continues for a set time of, for example, 3 seconds, and the maximum value and minimum value of the lateral displacement yLd within that period When the specific condition that the deviation is equal to or less than the deviation set value is satisfied, it is determined that the vehicle 1 is traveling on the travel line preferred by the driver. The steering torque set value, set time, and deviation set value may be set in advance.

  Here, when the specific condition is satisfied, the steered wheels are controlled not only by the steering assist by the vehicle steering device but also by the steering torque applied by the driver himself. Further, in this case, the steering by the driver himself so that the vehicle 1 travels on a specific line without the lateral displacement yLd changing, that is, the vehicle 1 continuously travels on the travel line preferred by the driver. Is considered to be continuing.

  Therefore, the lateral displacement correction value calculation unit 24 determines that the vehicle 1 is traveling on a travel line preferred by the driver when the specific condition is satisfied. On the other hand, the lateral displacement correction value calculation unit 24 determines that the vehicle 1 is not traveling on the travel line preferred by the driver when the specific condition is not satisfied. In addition, since it is a requirement that the specific condition is satisfied that a period in which the absolute value of the steering torque is larger than the steering torque setting value is longer than the setting time, an erroneous determination due to temporary steering by the driver is avoided. be able to.

  The lateral displacement correction value calculation unit 24 determines whether or not the vehicle 1 is traveling on a travel line preferred by the driver from the travel state amount using a travel state amount different from the steering torque. It may be configured.

  Specifically, for example, the lateral displacement correction value calculation unit 24 determines whether or not the vehicle 1 is traveling on a travel line preferred by the driver from the steering angle or yaw rate input from the travel state amount detection unit 26. It may be configured to. In this case, the travel state amount detection unit 26 is configured to output the steering angle or yaw rate of the vehicle 1 to the lateral displacement correction value calculation unit 24 as the travel state amount of the vehicle 1.

  Here, when the vehicle 1 continues to travel on the travel line preferred by the driver, the steering angle and the yaw rate of the vehicle 1 do not vary greatly during the travel.

  Therefore, the lateral displacement correction value calculation unit 24 causes the vehicle 1 to travel on the travel line preferred by the driver when a specific condition is satisfied that the steering angle or the yaw rate is within the set range for the set time or longer. It is determined that On the other hand, when the specific condition is not satisfied, it is determined that the vehicle 1 is not traveling on the travel line preferred by the driver.

  Further, the lateral displacement correction value calculation unit 24 may be configured to determine whether or not the vehicle 1 is traveling on a travel line preferred by the driver from the lateral acceleration input from the travel state amount detection unit 26. Good. In this case, the travel state amount detection unit 26 is configured to output the lateral acceleration of the vehicle 1 to the lateral displacement correction value calculation unit 24 as the travel state amount of the vehicle 1.

  Here, when a disturbance such as a crosswind or a cant is applied in the lateral direction of the vehicle, the vehicle 1 is displaced in the lateral direction. Therefore, the travel line on which the vehicle 1 is currently traveling is the travel line preferred by the driver. Not guaranteed.

  Therefore, the lateral displacement correction value calculation unit 24 determines whether or not a disturbance is applied in the lateral direction of the vehicle from the lateral acceleration input from the travel state amount detection unit 26. Subsequently, when the lateral displacement correction value calculation unit 24 determines that a disturbance is applied in the lateral direction of the vehicle, the lateral displacement correction value calculation unit 24 determines that the vehicle 1 is not traveling on the travel line preferred by the driver. On the other hand, when it is determined that no disturbance is applied in the lateral direction of the vehicle, the lateral displacement correction value calculation unit 24 determines that the vehicle 1 is traveling along a travel line preferred by the driver.

  In addition, when the vehicle 1 is traveling on a cant, a lateral acceleration is applied to the vehicle 1 regardless of whether the vehicle 1 is turning. Therefore, when the period during which the lateral acceleration of the vehicle 1 is within the set range larger than the lateral acceleration set value continues for a set time or longer, it may be determined that a disturbance is applied in the lateral direction of the vehicle. Further, the lateral acceleration set value may be set in advance.

  As described above, the lateral displacement correction value calculation unit 24 sets the travel line preferred by the driver to the vehicle 1 when the travel state amount input from the travel state amount detection unit 26 is within the set range for the set time or longer. Is determined to be traveling.

  By combining the above-described determination methods, the lateral displacement correction value calculation unit 24 is configured to determine whether or not the vehicle 1 is traveling on a travel line preferred by the driver from a plurality of travel state quantities. May be. As described above, the determination by the lateral displacement correction value calculation unit 24 is performed using a plurality of travel state quantities, so that erroneous determination can be avoided, and as a result, determination accuracy is improved. be able to.

  In step S202, the lateral displacement correction value calculation unit 24 calculates a lateral displacement learning candidate value and proceeds to step S203.

  Specifically, the lateral displacement correction value calculating unit 24 adds the lateral displacement yLd input from the lateral displacement calculating unit 23 and the lateral displacement input during a past period that is, for example, 3 seconds earlier than the current time. Considering yLd, an averaging process for calculating an average value of these lateral displacements yLd is performed, and the average value is set as a lateral displacement learning candidate value.

  As described above, the lateral displacement correction value calculation unit 24 uses the average value of the lateral displacement yLd input from the past displacement to the present time as the lateral displacement learning candidate value. Therefore, fluctuations in the lateral displacement learning candidate value due to the driver's temporary steering can be suppressed. Note that the lateral displacement correction value calculation unit 24 may be configured to directly use the lateral displacement yLd input from the lateral displacement calculation unit 23 as a lateral displacement learning candidate value without performing the averaging process.

  In step S203, the lateral displacement correction value calculation unit 24 limits the lateral displacement learning candidate value, and proceeds to step S204.

  Specifically, the lateral displacement correction value calculation unit 24 sets the upper and lower limit values of the lateral displacement learning candidate value, and corrects the lateral displacement learning candidate value according to the set upper and lower limit values.

  Here, with respect to the lateral displacement learning candidate value calculated in step S202, a lateral displacement learning candidate value having a large absolute value so that at least the vehicle 1 deviates from the traveling lane is not desirable.

  Therefore, the lateral displacement correction value calculation unit 24 sets the upper and lower limit values of the lateral displacement learning candidate value. With regard to the setting method of the upper and lower limit values, for example, the difference between the half value of the traveling road width and the half value of the vehicle width of the vehicle 1 is set as the upper limit value, and the reverse sign value of the upper limit value is set as the lower limit value do it.

  Further, when the lateral displacement learning candidate value is included in the range from the set lower limit value to the upper limit value, the lateral displacement correction value calculation unit 24 does not correct the lateral displacement learning candidate value.

  On the other hand, when the lateral displacement learning candidate value is not included in the range from the set lower limit value to the upper limit value, the lateral displacement learning candidate value is corrected so that the lateral displacement learning candidate value is included in the range. For example, if the lateral displacement learning candidate value is less than the lower limit value, the lateral displacement correction value calculation unit 24 corrects the lateral displacement learning candidate value to be the lower limit value, and the lateral displacement learning candidate value is greater than the upper limit value. If it is larger, the lateral displacement learning candidate value is corrected so as to be the upper limit value.

  As described above, the lateral displacement correction value calculation unit 24 sets the upper and lower limit values of the lateral displacement learning candidate value, and corrects the lateral displacement learning candidate value from the set upper and lower limit values. That is, an arbitrary restriction is provided for the lateral displacement learning candidate value calculated in step S202. Therefore, deviation from the travel lane of the vehicle 1 can be avoided and approach of the vehicle 1 to the travel lane or an adjacent vehicle can be avoided.

  In step S204, the lateral displacement correction value calculation unit 24 determines the lateral displacement learning value yLd_lrn, and proceeds to step S205.

  Specifically, the lateral displacement correction value calculation unit 24 operates according to the value of the lateral displacement learning storage value update flag determined in step S201.

  First, the operation of the lateral displacement correction value calculation unit 24 when the lateral displacement learning storage value update flag is “1” will be described.

  Here, a table in which the vehicle speed and the lateral displacement learning storage value are associated is stored in the storage unit. This table is divided into, for example, three stages of a low speed area, a medium speed area, and a high speed area as the speed area of the vehicle speed, and a lateral displacement learning storage value is associated with each area.

  When the lateral displacement learning storage value update flag is “1”, the lateral displacement correction value calculation unit 24 selects a lateral displacement learning storage value corresponding to the speed region of the vehicle speed input from the traveling environment detection unit 27 from the table. To do. For example, if the speed region of the vehicle speed input from the traveling environment detection unit 27 is a medium speed region, the lateral displacement correction value calculation unit 24 selects a lateral displacement learning storage value corresponding to the medium speed region from the table.

  Subsequently, the lateral displacement correction value calculation unit 24 updates the selected lateral displacement learning storage value by replacing it with a lateral displacement learning candidate value. That is, instead of the existing lateral displacement learning stored value corresponding to the speed region of the vehicle speed, the lateral displacement learning candidate value after executing step S203 becomes a new lateral displacement learning stored value.

  Further, the lateral displacement correction value calculation unit 24 sets the lateral displacement learning storage value after update, that is, the lateral displacement learning candidate value as the lateral displacement learning value yLd_lrn.

  Next, the operation of the lateral displacement correction value calculation unit 24 when the lateral displacement learning storage value update flag is “0” will be described.

  When the lateral displacement learning stored value update flag is “0”, the lateral displacement correction value calculating unit 24 stores the lateral displacement learning stored value corresponding to the speed region of the vehicle speed included in the traveling environment input from the traveling environment detecting unit 27. From the table.

  Subsequently, the lateral displacement correction value calculation unit 24 sets the selected lateral displacement learning storage value as the lateral displacement learning value yLd_lrn.

  Here, when the vehicle speed of the vehicle 1 is in the high speed region, the steered wheels fluctuate greatly with a slight driver's force as compared with the case where the vehicle speed is in the low speed region. As a result, the vehicle 1 travels. It will be easy to deviate from the lane. Therefore, when the vehicle speed is in the high speed region, it tends to be preferred to travel near the center of the travel lane compared to the case where the vehicle speed is in the low speed region.

  Therefore, as described above, the lateral displacement learning value yLd_lrn is determined according to the travel environment input from the travel environment detection unit 27, that is, the vehicle speed. By configuring in this way, it is possible to cope with changes in the driver's preference accompanying changes in the vehicle speed, and as a result, the steered wheels can be controlled so that the vehicle 1 travels on the driving line preferred by the driver. it can.

  Note that the lateral displacement correction value calculation unit 24 may be configured to operate according to the value of the lateral displacement learning storage value update flag using a traveling environment different from the vehicle speed, as described above.

  Specifically, for example, the travel path recognition unit 21 calculates the curvature of the travel path from the front image data input from the camera 9 and outputs the curvature to the lateral displacement correction value calculation unit 24 as the travel environment. That is, the travel path recognition unit 21 functions as the travel environment detection unit 27 that detects the curvature of the travel path as the travel environment. The storage unit stores a table in which the curvature and the lateral displacement learning storage value are associated with each other. The lateral displacement correction value calculation unit 24 determines the lateral displacement learning value yLd_lrn according to the curvature input from the travel path recognition unit 21 instead of the vehicle speed.

  Here, depending on the driver, the driving line preferred by the driver may differ between the straight traveling and the turning traveling. Therefore, it is effective to configure as described above so as to cope with a change in preference accompanying a change in the curvature of the travel path.

  As described above, the lateral displacement correction value calculation unit 24 selects a lateral displacement learning storage value corresponding to the travel environment input from the travel environment detection unit 27 from the table. Further, when it is determined that the vehicle 1 is traveling on a driving line preferred by the driver, the selected lateral displacement learning memory value is replaced with the lateral displacement learning candidate value and updated, and the updated lateral displacement learning is performed. The stored value is set as a lateral displacement learning value yLd_lrn. On the other hand, when it is determined that the vehicle 1 is not traveling on the driving line preferred by the driver, the selected lateral displacement learning memory value is set as the lateral displacement learning value yLd_lrn.

  When the lateral displacement correction value calculation unit 24 determines that the vehicle 1 is traveling on the travel line preferred by the driver, the lateral displacement learning value is set as the lateral displacement learning value yLd_lrn and the lateral displacement learning candidate. The value may be stored in the storage unit. In this case, when the lateral displacement correction value calculation unit 24 determines that the vehicle 1 is not traveling on the travel line preferred by the driver, the lateral displacement correction value calculation unit 24 is not the current lateral displacement learning candidate value but the latest lateral displacement stored in the storage unit. Let the displacement learning candidate value be the lateral displacement learning value yLd_lrn. With this configuration, the lateral displacement learning value yLd_lrn can be calculated without inputting the travel environment from the travel environment detection unit 27.

  In step S205, the lateral displacement correction value calculation unit 24 limits the amount of change per hour in the lateral displacement learning value yLd_lrn, and proceeds to step S206.

  Specifically, the lateral displacement correction value calculation unit 24 applies a filter process to the lateral displacement learning value yLd_lrn in step S204, and proceeds to step S206.

  Here, the lateral displacement correction value yLd_c changes abruptly according to the lateral displacement learning value yLd_lrn determined in step S204, and as a result, the behavior of the vehicle 1 may change suddenly. Therefore, in order to suppress a sudden change in the behavior of the vehicle 1, a filter process is applied to suppress a sudden change in the amount of change per hour of the lateral displacement learning value yLd_lrn.

  For example, a general primary low-pass filter may be used as the filter, and the crossover frequency of the filter may be set to a sufficiently low frequency, for example, 1 Hz, so that fluctuations in the vehicle 1 are not uncomfortable.

  In this way, the lateral displacement correction value calculation unit 24 performs a filter process that suppresses a sudden change in the amount of change per hour of the lateral displacement learning value yLd_lrn.

  In step S206, the lateral displacement correction value calculation unit 24 calculates the lateral displacement correction value yLd_c by subtracting the lateral displacement learning value yLd_lrn from the lateral displacement yLd.

  Next, details of the target rudder angle calculation process by the target rudder angle calculation unit 25 in step S104 will be described with reference to FIG. FIG. 9 is a flowchart showing a series of processing of the target rudder angle calculation process executed by the target rudder angle calculation unit 25 of FIG.

  In step S301, the target rudder angle calculation unit 25 calculates the coefficients k1, k2, and k3 according to equations (18), (19), and (20), and proceeds to step S302.

  For the parameters included in each of the coefficients k1 to k3, Lf and Lr are values determined for each vehicle because of the distance between the center of gravity and the wheel axis. On the other hand, Cf and Cr are values related to the frictional force of the tire and change depending on the road surface condition or the tire, and λ is also a value related to the control response. Therefore, it is desirable to change Cf, Cr, and λ according to the situation.

  In addition, since the vehicle speed is included in the coefficients k1 and k3, and Ld may be changed according to the vehicle speed, the coefficients k1 to k3 are preferably changed according to the vehicle state quantity. In particular, the response to the steering angle control needs to be suppressed in a vehicle speed having a large influence on the vehicle behavior change with respect to the steering angle change or on a traveling road with a low road surface friction coefficient. Therefore, the coefficients k1 to k3 have an influence on Cf and Cr. It is desirable to change according to a road surface friction coefficient with large. Thus, if the coefficients k1 to k3 are changed according to the situation, appropriate control can be performed.

  In step S302, the target rudder angle calculation unit 25 calculates the target rudder angle basic value ang_bs according to the equation (21), and proceeds to step S303. In Equation (21), θ corresponds to the target rudder angle basic value ang_bs.

  Specifically, the target rudder angle calculation unit 25 calculates the coefficients k1 to k3 calculated in step S301, the lateral displacement correction value yLd_c calculated in step S103, and the target travel line inclination angle calculated by the travel path recognition unit 21. The target rudder angle basic value ang_bs is calculated by substituting eLd and the yaw rate γ ′ input from the vehicle state quantity detection unit 28 into the equation (21).

  In step S303, the target rudder angle calculation unit 25 calculates a post-limit target rudder angle basic value ang_clp by performing a restriction process on the target rudder angle basic value ang_bs calculated in step S302.

  Here, when the target rudder angle ang_tg becomes an excessive value, there is a risk of deviating from the conditions under which the two-wheel model shown in FIG. 5 can be applied, and Cf and Cr characteristics also change greatly.

  Therefore, a restriction process is performed on the target rudder angle basic value ang_bs so that the target rudder angle ang_tg does not become an excessive value. Further, since the centrifugal force increases when the steering angle increases during high speed traveling of the vehicle 1, it is necessary to perform such a limiting process in order to suppress lateral acceleration.

  Specifically, the target rudder angle calculation unit 25 sets a value obtained by restricting the target rudder angle basic value ang_bs so that the lateral acceleration is equal to or lower than the lateral acceleration set value according to the vehicle speed. Calculated as the value ang_clp. The lateral acceleration set value may be set in advance, for example, 0.2G.

  Finally, in step S304, the target rudder angle calculation unit 25 calculates the target rudder angle ang_tg from the post-limit target rudder angle basic value ang_clp calculated in step S303, and ends the series of processes.

  Here, since it is not desirable that the vehicle behavior changes suddenly, it is desirable to limit the amount of change per unit time of the target rudder angle ang_tg, and the vehicle behavior with respect to the rudder angle change increases as the vehicle speed increases. Therefore, in step S304, the target rudder angle ang_tg is limited so that the amount of change decreases as the vehicle speed increases.

  The target rudder angle calculation unit 25 uses the previous target rudder angle ang_tg_old stored in the storage unit and the change amount limit value dlt_ang set according to the vehicle speed, to the post-restriction target rudder angle basic value ang_clp. The target rudder angle ang_tg is calculated by performing the restriction process. Specifically, the target rudder angle calculation unit 25 sets the target rudder angle basic value ang_clp after the restriction so that the after-restricted target rudder angle basic value ang_clp is included in the range of ang_tg_old-dlt_ang to ang_tg_old + dlt_ang. Calculated as the steering angle ang_tg.

  Next, the effects realized by the vehicle steering apparatus of the present invention will be described in detail. Here, as a comparative example with the present invention, the steering control unit 29 uses the steered wheels so that the vehicle 1 travels the target travel line line_tg set by the target travel line setting unit 22 instead of the travel line preferred by the driver. Consider the case of control.

  In this case, since the steering assist is performed so that the vehicle 1 follows the target travel line line_tg regardless of the driver's preference, the vehicle continues to travel at the driver's favorite travel position. As a result, the driver may feel uncomfortable.

  In addition, when the driver steers the vehicle at the travel position desired by the driver at the timing when the steering assist by the vehicle steering device is performed, the steering assist by the vehicle steering device This may conflict with the steering by the driver, and as a result, traveling stability may be reduced.

  On the other hand, in the vehicle steering apparatus of the present invention, the travel line preferred by the driver displaced by the lateral displacement learning value yLd_lrn set according to the driver's characteristics with respect to the target travel line line_tg Steering assistance is performed so that the vehicle travels. Accordingly, the steered wheels can be controlled in consideration of the driver's preference.

  As described above, according to the first embodiment, the lateral displacement corresponding to the forward gazing distance of the vehicle is calculated from the forward travel path information and the target travel line, and the vehicle is It is comprised so that it may determine whether it is drive | working the driving line which it likes. In addition, a lateral displacement learning value is calculated from the lateral displacement according to the determination result, and the lateral displacement changing speed is calculated so that the lateral displacement correction value corresponding to the deviation between the lateral displacement and the lateral displacement learning value decreases. The target rudder angle is calculated by controlling the speed.

  Thus, the steered wheels can be controlled so that the vehicle travels on the travel line preferred by the driver. Further, since the vehicle travels on the travel line preferred by the driver, the steering of the steered wheels by the driver does not conflict with the steering assist by the vehicle steering device, and as a result, the vehicle can travel stably.

  In the first embodiment, the lateral displacement correction value calculation unit 24 calculates the lateral displacement learning value yLd_lrn from the lateral displacement yLd corresponding to the forward gazing distance Ld calculated by the lateral displacement calculation unit 23, A deviation between the displacement yLd and the lateral displacement learning value yLd_lrn is provided to the target rudder angle calculation unit 25 as a lateral displacement correction value yLd_c. However, a vehicle position lateral displacement calculator that calculates a lateral displacement corresponding to the current vehicle position, that is, a vehicle position lateral displacement that is a displacement between the current vehicle position and the target travel line line_tg, may be provided. In this case, the lateral displacement correction value calculation unit 24 calculates the lateral displacement learning value yLd_lrn from the vehicle position lateral displacement, and sets the deviation between the lateral displacement yLd and the lateral displacement learning value yLd_lrn as the lateral displacement correction value yLd_c, and the target steering angle The calculation unit 25 is configured to be provided. Even in such a configuration, the steered wheels can be controlled so that the vehicle travels on the travel line preferred by the driver, and the same effect as the vehicle steering apparatus shown in the first embodiment can be obtained. be able to.

  Moreover, although FIG. 2 demonstrated as a functional block diagram of a control unit, it is good also as a functional block diagram of the whole vehicle steering device. In this case, the travel path recognition unit 21 further includes a camera 9 and captures a front image in order to recognize the travel path. The travel path recognition unit 21 provides front travel path information to the target travel line setting unit 22, the lateral displacement calculation unit 23, the lateral displacement correction value calculation unit 24, and the target rudder angle calculation unit 25.

  The travel state amount detection unit 26 further includes a steering torque detection unit 8 and a lateral displacement calculation unit 23, detects the steering torque, calculates the lateral displacement yLd, and provides the lateral displacement correction value calculation unit 24 with it. The travel environment detection unit 27 further includes a vehicle speed detection unit 6, detects the vehicle speed of the vehicle, and provides the detection result to the lateral displacement correction value calculation unit 24. The vehicle state quantity detection unit 28 further includes a vehicle speed detection unit 6 and a yaw rate detection unit 7, detects the vehicle speed and yaw rate of the vehicle, and provides the detection result to the target rudder angle calculation unit 25.

  In the first embodiment, the steering control unit 29 is based on an electric power steering device. However, any steering control unit 29 may be used as long as it can control steering. For example, a steering-by-wire that eliminates a mechanical link between a steering wheel and a steered wheel. It may be based on a steering device called.

  Moreover, although the traveling path recognition part 21 has produced | generated forward traveling path information using the front image data input from the camera 9, it is not restricted to this. For example, the forward travel route information may be generated using map information and vehicle position information obtained from a car navigation system using GPS (Global Positioning System). The yaw angle may be detected by integrating the yaw rate or comparing the target travel line with the actual travel locus.

  In this Embodiment 1, although the case where this invention was applied with respect to the system which assumed lane keep assistance was described, this invention may be applied not only to this but a parking assistance system, an automatic driving system, etc. . The present invention is applicable when steering steered wheels so as to follow a target travel line set in each system.

  1 vehicle, 2 handle, 3 motor, 4 steering mechanism, 5 tires, 6 vehicle speed detection unit, 7 yaw rate detection unit, 8 steering torque detection unit, 9 camera, 10 control unit, 21 travel path recognition unit, 22 target travel line setting Unit, 23 lateral displacement calculation unit, 24 lateral displacement correction value calculation unit, 25 target rudder angle calculation unit, 26 travel state amount detection unit, 27 travel environment detection unit, 28 vehicle state amount detection unit, 29 steering control unit, 101 interface , 102 processor, 103 memory.

Claims (12)

A travel path recognition unit that generates front travel path information by recognizing a travel path on which the vehicle travels;
A target travel line setting unit that sets a target travel line that is a target when the vehicle follows the travel path from the front travel path information;
A lateral displacement calculation unit that calculates a lateral displacement corresponding to a forward gazing distance of the vehicle from the forward travel path information and the target travel line;
A running state amount detection unit for detecting a running state amount of the vehicle;
From the travel state quantity, it is determined whether or not the vehicle is traveling on a travel line preferred by the driver, and a lateral displacement learning value is calculated from the lateral displacement according to a determination result, and the lateral displacement and the lateral displacement are calculated. A lateral displacement correction value calculation unit for calculating a deviation from the displacement learning value as a lateral displacement correction value;
A target rudder angle calculation unit that calculates a target rudder angle based on a lateral speed that is a change speed of the lateral displacement so that the lateral displacement correction value decreases;
A steering control unit for controlling the steering angle of the vehicle from the target steering angle;
A vehicle steering apparatus comprising: A vehicle position lateral displacement calculating unit that calculates a vehicle position lateral displacement corresponding to the current position of the vehicle;
The vehicle steering apparatus according to claim 1, wherein the lateral displacement correction value calculation unit calculates the lateral displacement learning value from the vehicle position lateral displacement instead of the lateral displacement. A vehicle state quantity detection unit for detecting a vehicle state quantity of the vehicle;
The front travel path information includes a target travel line inclination angle corresponding to the front gaze distance,
The target rudder angle calculation unit
The vehicle steering apparatus according to claim 1, wherein the target steering angle is calculated from the vehicle state quantity, the target travel line inclination angle, and the lateral displacement correction value. The vehicle state quantity includes a yaw rate of the vehicle,
When the target rudder angle is expressed as θ, the coefficients are k1, k2 and k3, the lateral displacement correction value is expressed as yLd_c, the target travel line inclination angle is expressed as eLd, and the yaw rate is expressed as γ ′,
The target rudder angle calculation unit calculates the target rudder angle according to the following equation: θ = k1 · yLd_c + k2 · eLd−k3 · γ ′
The vehicle steering device according to claim 3. The lateral displacement correction value calculation unit determines that the vehicle is traveling on a travel line preferred by the driver when the travel state amount is within a set range for a set time or longer. The vehicle steering device according to any one of the above. The vehicle steering apparatus according to any one of claims 1 to 5, wherein the travel state quantity includes at least one of a steering torque, a steering angle, a yaw rate, and a lateral acceleration. The lateral displacement correction value calculation unit
7. The lateral displacement learning value is calculated from the lateral displacement learning candidate value using an average value of the lateral displacement input from the lateral displacement calculating unit from the past to the present time, and the lateral displacement learning value is calculated from the lateral displacement learning candidate value. The vehicle steering device according to claim 1. A traveling environment detection unit for detecting the traveling environment of the vehicle;
A storage unit that stores a table that associates the travel environment and the lateral displacement learning storage value;
Further comprising
The lateral displacement correction value calculation unit
Select the lateral displacement learning stored value corresponding to the traveling environment from the table,
When it is determined that the vehicle is traveling on the travel line preferred by the driver, the selected lateral displacement learning stored value is replaced with the lateral displacement learning candidate value and updated, and the updated lateral displacement is stored. The displacement learning memory value is the lateral displacement learning value,
The vehicle steering apparatus according to claim 7, wherein when it is determined that the vehicle is not traveling on a travel line preferred by the driver, the selected lateral displacement learning memory value is used as the lateral displacement learning value. The vehicle steering apparatus according to claim 8, wherein the travel environment is a vehicle speed of the vehicle or a curvature of the travel path. The lateral displacement correction value calculation unit sets upper and lower limit values of the lateral displacement learning candidate value, and corrects the lateral displacement learning candidate value from the set upper and lower limit values. The vehicle steering device according to claim 1. The vehicle steering apparatus according to any one of claims 1 to 10, wherein the lateral displacement correction value calculation unit performs a filter process that suppresses a sudden change in an amount of change per hour of the lateral displacement learning value. A travel path recognition step for generating forward travel path information by recognizing a travel path on which the vehicle travels;
A target travel line setting step for setting a target travel line that is a target when the vehicle follows the travel path from the front travel path information;
A lateral displacement calculating step of calculating a lateral displacement corresponding to a forward gazing distance of the vehicle from the forward travel path information and the target travel line;
A running state amount detecting step for detecting a running state amount of the vehicle;
From the travel state quantity, it is determined whether or not the vehicle is traveling on a travel line preferred by the driver, and a lateral displacement learning value is calculated from the lateral displacement according to a determination result, and the lateral displacement and the lateral displacement are calculated. A lateral displacement correction value calculating step for calculating a deviation from the displacement learning value as a lateral displacement correction value;
A target rudder angle calculating step of calculating a target rudder angle based on a lateral speed that is a change speed of the lateral displacement so that the lateral displacement correction value decreases;
A steering control step for controlling the steering angle of the vehicle from the target steering angle;
A vehicle steering method comprising:

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