JP2017154705A - Steering amount control device and steering amount control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering amount control device and a steering amount control method capable of preventing discomfort felt by a driver or the like accompanying a change in a steering amount and allowing a vehicle to travel with an appropriate traveling route.SOLUTION: There is provided a steering amount control device 20 which is applied to a steering device 40 for changing the steering amount of a vehicle, and which acquires a target steering amount of the steering device on the basis of a curvature of a traveling path of the vehicle, the steering amount control device 20 including: a position setting unit for setting a forward position in the vehicle traveling direction from the current vehicle position as a position for acquiring the curvature; and a target steering amount acquisition unit for acquiring the target steering amount on the basis of the set curvature at the forward position.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steering amount control device or a steering amount control method for acquiring a target steering amount for changing a steering amount of a vehicle.

  For example, a steering amount control device that sets a travel route of a vehicle based on a captured image in front of the vehicle or information supplied from a navigation device and acquires a target steering amount so that the vehicle can travel along the travel route is known. It has been. Further, in such a steering amount control device, an upper limit value of the steering amount is set in consideration of prevention of driver's uncomfortable feeling due to a large steering change, safety, and the like.

  At the entrance of a curve or the like, the change in the curvature of the travel route is large, and the steering amount may reach an upper limit value. If the steering amount reaches the upper limit during traveling, the steering amount cannot be increased, and the vehicle may not be able to follow the traveling route. For this reason, Patent Literature 1 discloses a steering amount control device that improves followability of a vehicle with respect to a travel route by relaxing an upper limit value of the steering amount at a curve entrance or the like.

JP 2008-44531 A

  When the upper limit value of the steering amount is relaxed, a sudden increase in the steering amount (rapid steering) occurs. Such sudden steering increases the acceleration of the steering amount, and increases the chance of causing the driver to feel uncomfortable. On the other hand, simply prohibiting sudden steering does not provide a desired steering amount when the curvature change of the travel route is large, and the followability of the vehicle to the travel route is deteriorated.

  The present invention has been made in view of the above problems, and a steering amount control device capable of preventing a driver from feeling uncomfortable with a change in the steering amount and allowing the vehicle to travel along an appropriate travel route, and a steering amount. An object is to provide a control method.

  In order to solve the above problems, the present invention is a steering amount control device that is applied to a steering device that changes the steering amount of a vehicle and acquires a target steering amount of the steering device based on a curvature of a traveling route of the vehicle. Then, at the current position of the vehicle, a position setting unit that sets a front position in the vehicle traveling direction from the current position as a position for acquiring the curvature, and based on the set curvature at the front position, And a target steering amount acquisition unit that acquires the target steering amount.

  In a travel route with a large change in curvature, the followability of the vehicle to the travel route is poor. Therefore, the front position is set in the vehicle traveling direction from the current position of the vehicle, and the target steering amount is set based on the curvature at the set position. Since this target steering amount is set based on the curvature of the front position, the timing at which the steering apparatus starts steering with respect to the front position is advanced. For example, at the entrance of the curve, the timing at which the steering is started is advanced, so that the vehicle is prevented from greatly expanding with respect to the travel route. As a result, it is possible to suppress the driver's uncomfortable feeling associated with the sudden steering, and to make the vehicle travel on an appropriate path.

1 is a configuration diagram of a driving support system 100. FIG. The figure explaining the runway parameter acquired by ECU20. The flowchart explaining the driving assistance control which ECU20 implements. The figure explaining the traveling lane detected by ECU20. The figure explaining change of the amount of steerings when ECU20 does not look ahead at observation position P. FIG. The figure explaining the change of the amount of steerings when ECU20 prefetches observation position P. FIG. The flowchart explaining the process which ECU20 implements by step S11 of FIG. The figure explaining the relationship between vehicle direction (yaw angle (phi)) and an acceleration upper limit. The figure explaining the relationship between the acceleration upper limit after a change, and distance (DELTA) L. The figure explaining the relationship between the vehicle speed V and distance ((DELTA) L). The figure explaining the relationship between the variation | change_quantity of curvature (rho), and distance ((DELTA) L).

  Embodiments according to the present invention will be described with reference to the drawings. In the following embodiments, the steering amount control device will be described as an electronic control unit (ECU) that is a part of a driving support system incorporated in a vehicle. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the same reference numerals is used.

(First embodiment)
The driving support system 100 shown in FIG. 1 mainly includes a steering device 40 that changes the steering amount of the vehicle, an ECU 20 that sets a target steering amount M for changing the steering amount of the steering device 40, and various detection units. In preparation.

  The steering device 40 is, for example, an electric power steering device (EPS) and applies a steering torque to the steering shaft 42 connected to the handle 41 by the rotation of the motor 44 to set the steering amount of the vehicle CS. To do. A pinion gear 45 is provided at the tip of the steering shaft 42. The pinion gear 45 meshes with the rack gear 46. A pair of wheels are rotatably connected to both ends of the rack gear 46 via tie rods or the like. A motor 44 is attached to the steering shaft 42 via a reduction gear 43.

  The EPS controller 24 is a well-known computer including a CPU, ROM, and RAM (not shown), and is connected to the motor 44 of the steering device 40. In the steering amount control performed by the EPS controller 24, the current amount and voltage for controlling the rotation angle and torque of the motor 44 are set based on the target steering amount M output from the ECU 20.

  The various detection units include a camera device 31, a vehicle speed sensor 32, a navigation device 33, and a steering angle sensor 34.

  The camera device 31 acquires a captured image in front of the traveling direction of the vehicle CS, and detects a lane mark based on the captured image. The camera device 31 is a device including a monocular camera or a stereo camera such as a CCD image sensor, a CMOS image sensor, a near-infrared sensor, and the like, and is attached near the upper end of the windshield of the vehicle CS and near the center in the vehicle width direction. Yes. The lane mark is an index used for specifying the position of the travel lane. As an example, in this embodiment, a white line that divides the travel lane is used.

  For example, the camera device 31 cuts out an image necessary for detecting white lines that divide the left and right of the travel lane in which the vehicle CS travels from the captured image. Next, the camera device 31 detects the position of the white line included in each image. As an example of a method for detecting a white line, an edge point is extracted by applying a sobel filter or the like to an image, and Hough transform or the like is performed on the extracted edge point to detect edge points constituting left and right white lines. Then, the camera device 31 calculates the coordinates of the edge point of the white line on the image plane, and sets the calculated coordinates as the white line. And the camera apparatus 31 transmits the information of the detected white line to ECU20 with a predetermined period.

  The vehicle speed sensor 32 outputs a signal corresponding to the rotational speed of the wheel. The vehicle speed sensor 32 detects the rotational speed of the wheel based on, for example, the number of pulses per unit time output from a pulse generator attached to the wheel, and outputs it to the ECU 20.

  The navigation device 33 calculates the current position of the vehicle using the GPS signal received by the GPS receiver and information acquired by various sensors, searches for a route from the calculated position to the destination, Provide guidance. In addition, the navigation device 33 can acquire information such as the number of lanes of the travel lane on which the vehicle travels, the curvature ρ, and the cant from the position of the vehicle and the road information stored in the map database.

  The steering angle sensor 34 detects the steering amount of the steering device 40. The steering angle sensor 34 is attached to the steering shaft 42, detects the rotation angle (steering angle) of the handle 41, and outputs it to the ECU 20.

  The ECU 20 is configured as a well-known microcomputer mainly composed of a CPU 21, ROM 22, and RAM 23. The CPU 21 executes a program stored in the ROM 22 to detect a travel lane (travel route) and set a target steering amount M.

  The ECU 20 detects a travel lane in which the vehicle CS travels based on the white line information output from the camera device 31. In the detection of the travel lane, for example, the center coordinates and the travel path parameters in the travel width direction defined by the left and right white lines detected by the camera device 31 are acquired. Hereinafter, the position where the ECU 20 acquires the travel path parameter and the like on the travel lane is also referred to as an observation position P.

  FIG. 2 is a diagram for explaining the travel path parameters acquired by the ECU 20. In this embodiment, the ECU 20 uses the curvature ρ at each observation position P in the travel lane, the yaw angle φ that is the inclination of the center line with respect to the vehicle traveling direction, and the lateral position Q of the vehicle CS with respect to the center line of the travel lane as the travel path parameters. A lateral deviation dy, which is a deviation amount, is acquired. The center line is a line passing through the center coordinates acquired as the observation position P described above.

  The ECU 20 sets the target steering amount M based on the acquired travel path parameter. In this embodiment, the ECU 20 performs target steering based on the curvature steering amount DA that is mainly set based on the curvature ρ and the current steering angle X that is set by the driver operating the steering device 40. Set the amount M.

  Next, driving support control performed by the ECU 20 will be described with reference to the flowchart of FIG. The flowchart shown in FIG. 3 is executed by the ECU 20 at a predetermined cycle. FIG. 4 is a diagram illustrating a traveling lane detected by the ECU 20.

  In step S11, an acceleration upper limit value for the target steering amount M is set. The acceleration upper limit value is a value that defines an upper limit of acceleration when the steering device 40 changes the steering amount, and is a value used when the ECU 20 sets the target steering amount M. In the first embodiment, the acceleration upper limit value is a predetermined fixed value. Note that switching between setting and not setting the acceleration upper limit value may be performed by operating an operation switch (not shown) or the like. Therefore, step S11 functions as an acceleration limiting unit and an acceleration limiting process.

  In step S12, a runway parameter is acquired. The ECU 20 calculates the travel path parameters (ρ, φ, Δy) based on the white line information at each observation position P output from the camera device 31. In FIG. 4, as an example, the ECU 20 calculates the travel path parameters (ρ, φ, Δy) at the observation positions P (1) to P (4) at the illustrated position of the vehicle CS. In this embodiment, each observation position P is acquired every 10 meters in the vehicle traveling direction, but is not limited to this, and the interval is set according to the performance of the camera device 31 and the processing speed of the ECU 20. It may be a thing.

  In step S13, the amount of change in the curvature ρ of the travel lane in the vehicle traveling direction is determined. For example, the ECU 20 determines the amount of change in the curvature ρ in the travel lane based on the curvature ρ at the plurality of observation positions P acquired in step S12. If the traveling lane in the vehicle traveling direction is a curve, the amount of change in the curvature ρ is large, and if the traveling lane is a straight line, the amount of change in the curvature ρ is small.

  If the amount of change in curvature ρ in the travel lane is less than the threshold TA (step S13: NO), in step S15, the observation position P for setting the target steering amount M for the travel lane is set in advance as the current position of the vehicle CS. To the observed observation position P. In FIG. 4, as an example, the current position of the vehicle CS is the observation position P (1).

  In this embodiment, the current position of the vehicle CS is the observation position P closest to the vehicle CS among the plurality of observation positions P observed by the camera device 31, but the current position is not limited to this. For example, when a plurality of observation positions P observed by the camera device 31 include an observation position P immediately below the vehicle CS, the position immediately below the vehicle CS may be the current position of the vehicle CS.

  On the other hand, if the amount of change in curvature ρ in the travel lane is greater than or equal to the threshold TA (step S13: YES), in step S14, the position for setting the target steering amount M for the travel lane is set in the vehicle traveling direction from the current position. Set to the front observation position P. In FIG. 4, the observation position P for acquiring the curvature ρ is set to the observation position P (2) ahead of the observation position (1) in the vehicle traveling direction. Therefore, steps S13, S14, and S15 function as a position setting unit and a position setting process.

  In step S16, the ECU 20 sets a target steering amount M for following the traveling lane based on the curvature ρ of the observation position P set in step S14 or S15. For example, the ECU 20 stores a map that defines the relationship between the curvature ρ, the vehicle speed V, and the current steering angle X acquired by the output from the steering angle sensor 34, and from the values stored in this map. A target steering amount M is set. Therefore, the process of step S16 functions as a target steering amount acquisition unit (target steering amount acquisition step).

  When the ECU 20 acquires the curvature ρ at the observation position P ahead in the vehicle traveling direction from the current position, the target steering amount M for following the traveling lane is a value corresponding to the observation position P ahead. Become. Hereinafter, the observation position P for acquiring the curvature ρ is changed to the observation position P ahead of the current position in the vehicle traveling direction, and acquiring the curvature ρ at the changed observation position P is simply the observation position P. It is also described as prefetching.

  In addition, when calculating the target steering amount M in step S16, the state steering amount DB may be considered. The state steering amount DB is calculated based on the lateral deviation Δy of the vehicle, the lane cant, and various disturbances.

  When the target steering amount M is calculated, the process shown in FIG. Since the target steering amount M set in step S16 is set within a range that does not exceed the acceleration upper limit value, the EPS controller 24 limits the steering angular acceleration of the steering amount output by the steering device 40.

  Next, a change in the travel route of the vehicle CS due to the target steering amount M set based on the change in the curvature ρ will be described. First, a change in the steering amount when the ECU 20 does not prefetch the observation position P will be described with reference to FIG.

  When the vehicle CS enters the curve, the amount of change in the curvature ρ of the traveling lane increases near the curve entrance (FIG. 5 (a), time t1-t3). Therefore, as shown in FIG. 5B, the ECU 20 increases the target steering amount M in order to cause the vehicle CS to follow this travel lane. At this time, if the steering angular acceleration is large, the vehicle CS is suddenly steered, causing the driver to feel uncomfortable. Therefore, as shown in FIG. 5D, the ECU 20 provides an acceleration upper limit value that limits the steering angular acceleration, and sets the target steering amount M so that the acceleration of the steering amount of the steering device 40 does not exceed the acceleration upper limit value. To do.

  On the other hand, when the amount of change in the curvature ρ of the travel lane is large, the target steering amount M set in a range not exceeding the acceleration upper limit value may cause a shortage of the steering amount for causing the vehicle CS to follow the travel lane. In FIG. 5B, the actual target steering amount M is insufficient with respect to the ideal target steering amount M (indicated by a dotted line in the figure) corresponding to the travel lane between times t1 and t2. Such a shortage of the target steering amount M becomes a factor that reduces the followability of the vehicle CS to the travel lane.

  In addition, when the curvature ρ of the traveling lane changes from an increase to a constant value (time t3-t4) due to the vehicle CS entering in the middle of the curve (time t3-t4), it is necessary to switch back the steering. . Also in this case, the ECU 20 sets the target steering amount M within a range that does not exceed the acceleration upper limit value (minus side) (FIGS. 5C and 5D). As a result, as shown in FIG. 5D, the actual target steering amount M does not immediately decrease with respect to the ideal target steering amount M, and the followability of the vehicle CS to the traveling lane is deteriorated.

  On the other hand, in the present embodiment, the ECU 20 prevents the follow-up of the vehicle CS with respect to the traveling lane by pre-reading the observation position P. FIG. 6 is a diagram for explaining a change in the steering amount when the ECU 20 prefetches the observation position P by the process shown in FIG.

  As shown in FIG. 6A, when the vehicle CS travels in a section where the curvature ρ increases, such as a curve entrance (t11-t12), the ECU 20 determines that the amount of change in the curvature ρ increases (FIG. 3). , Step S13), the observation position P is pre-read (Step S14). The ECU 20 acquires the curvature ρ at the observation position P ahead of the current position in the vehicle traveling direction, and sets the target steering amount M based on the acquired curvature ρ (step S16). Therefore, even when the steering angular acceleration of the target steering amount M is limited, the steering amount is prevented from becoming insufficient by advancing the timing of starting the steering. As a result, the actual travel route of the vehicle CS does not swell greatly outside the travel lane.

  Further, even when the vehicle CS enters the middle of the curve from the curve entrance where the curvature ρ decreases (t13-t14), the ECU 20 determines that the amount of change in the curvature ρ increases (step S13) and observes it. Prefetching of the position P is performed (step S14). Therefore, even when the steering angular acceleration of the target steering amount M is limited, the timing at which the steering is started is advanced to prevent the vehicle CS from greatly expanding outward with respect to the travel lane.

  When the vehicle CS travels in the middle of a curve where the change amount of the curvature ρ of the travel lane is small (t14-t15), the ECU 20 changes the observation position P from the front observation position P to the current position in the vehicle traveling direction. (Step S15). The ECU 20 does not pre-read the observation position P and does not advance the steering timing of the vehicle CS. Therefore, the actual travel route of the vehicle CS follows the travel lane. Although description is omitted, since the amount of change in the curvature ρ is large even in a section where the vehicle CS enters the curve exit from the middle of the curve, the ECU 20 performs the look-ahead of the observation position P.

  As described above, in the first embodiment, when the amount of change in the curvature ρ in the travel lane is large, the steering amount of the vehicle CS is insufficient, and the followability of the vehicle CS to the travel lane is deteriorated. Therefore, the ECU 20 sets the front position in the vehicle traveling direction from the current position of the vehicle CS as a position for acquiring the curvature, and sets the target steering amount M by the curvature ρ at the set front position. Since the target steering amount M is obtained by pre-reading the observation position P, the steering device 40 prevents the steering timing from being accelerated and the travel route of the vehicle CS from expanding outside the travel lane. As a result, it is possible to suppress the driver's uncomfortable feeling associated with sudden steering, and to make the vehicle CS travel on an appropriate road.

  The ECU 20 (position setting unit) sets the front position as a position for acquiring the curvature ρ when the amount of change in the curvature ρ of the travel lane is equal to or greater than a predetermined value in the vehicle traveling direction. When the amount of change in the curvature ρ in the travel route increases, the delay in turning off the steering accompanying the limitation of the acceleration of the target steering amount M increases, and the followability of the vehicle CS to the travel lane deteriorates. Therefore, when the vehicle CS travels in such a travel lane, the follow-up of the vehicle CS with respect to the travel lane can be prevented by setting the position where the curvature ρ is acquired as the front position.

(Second Embodiment)
The acceleration upper limit value of the target steering amount M may be changed according to the direction of the vehicle CS with respect to the travel lane. FIG. 7 is a flowchart for explaining the process performed by the ECU 20 in step S11 of FIG.

  In step S21, the direction of the vehicle CS is acquired. For example, the ECU 20 acquires the direction of the vehicle CS with respect to the travel lane based on the travel path parameter (yaw angle φ).

  In step S22, the acceleration upper limit value is changed according to the direction of the vehicle CS. FIG. 8 is a diagram for explaining the relationship between the vehicle direction (yaw angle φ) and the acceleration upper limit value. The ECU 20 stores, for example, a map that defines the relationship between the yaw angle φ and the acceleration upper limit value. In this map, the value is stored so that the acceleration upper limit value increases as the yaw angle φ increases. This is because the steerable steering is required to cause the vehicle CS to follow the traveling lane as the direction of the vehicle CS is directed outward with respect to the traveling lane.

  In step S14 in FIG. 3, the observation position P is pre-read using the set acceleration upper limit value. Therefore, it can be said that the ECU 20 sets the observation position P based on the acceleration of the target steering amount M limited by the acceleration upper limit value. FIG. 9 is a diagram for explaining the relationship between the changed acceleration upper limit value and the distance ΔL. The ECU 20 stores a map that defines the acceleration upper limit value and the distance ΔL from the current position of the vehicle CS to the observation position P to be prefetched. By referring to this map, the observation position to be prefetched is stored. Set P. This map stores the value so that the distance ΔL is set farther from the current position as the changed acceleration upper limit value decreases. Then, in step S16 of FIG. 3, the target steering amount M is set based on the curvature ρ of the observation position P that is the prefetch target.

  As described above, in the second embodiment, the ECU 20 (acceleration limiting unit) limits the acceleration of the target steering amount, and the ECU 20 (position setting unit) sets the observation position P according to the acceleration. With the above configuration, by limiting the angular acceleration (acceleration) of the target steering amount M, it is possible to prevent sudden steering due to a steep curve in the traveling lane or erroneous detection of the sensor and to prevent the driver from feeling uncomfortable.

  The ECU 29 (direction detection unit) detects the direction of the vehicle CS with respect to the travel route, and the ECU 20 (position setting unit) sets the observation position P based on the detected direction of the vehicle with respect to the travel route. When the difference between the direction of the vehicle CS and the direction of the traveling lane is large, a large steering amount acceleration is required to cause the vehicle CS to follow the traveling lane. On the other hand, when the difference in the direction of the vehicle CS with respect to the travel lane is small, the acceleration of the steering amount necessary for causing the vehicle CS to follow the travel lane is small. Therefore, by setting the look-ahead position based on the direction of the vehicle CS with respect to the road, it is possible to appropriately adjust the balance between the followability of the vehicle CS with respect to the travel lane and the frequency at which the driver feels uncomfortable due to sudden steering. .

  The ECU 20 changes the acceleration upper limit value based on the detected direction of the vehicle CS. By changing the limit value of the acceleration of the steering amount based on the direction of the vehicle CS with respect to the road, the balance between the followability of the vehicle CS with respect to the travel lane and the frequency at which the driver feels uncomfortable due to sudden steering is appropriately adjusted. be able to.

  The ECU 20 (position setting unit) pre-reads the observation position P by setting the distance ΔL farther from the current position as the changed acceleration upper limit value is lower. As the acceleration limit value decreases, the acceleration of the steering amount is suppressed, and the steering delay is likely to occur. Therefore, as the acceleration upper limit value is lower, the observation position P to be prefetched is set farther from the current position of the vehicle CS, so that the timing for starting the steering is advanced, and the followability of the vehicle CS to the traveling lane is deteriorated. Can be prevented.

(Third embodiment)
The setting of the observation position P to be prefetched may be set using the vehicle speed V in addition to the acceleration upper limit value.

  FIG. 10 is a diagram for explaining the relationship between the vehicle speed V and the distance ΔL from the current position to the observation position P to be read ahead in the third embodiment. For example, the ECU 20 stores a map that defines the relationship between the vehicle speed V and the distance ΔL. In this map, a value is stored so as to increase the distance ΔL as the vehicle speed V increases. In step S14 in FIG. 3, the ECU 20 refers to this map and sets the observation position P to be prefetched.

  As described above, in the third embodiment, the ECU 20 (position setting unit) sets the distance ΔL based on the vehicle speed V when pre-reading the observation position P. As the vehicle speed V increases, there are more opportunities for the driver to feel uncomfortable even with a small steering amount. Therefore, by setting the observation position P to be read ahead based on the vehicle speed V farther than the current position, it is possible to speed up the timing of starting the steering and to suppress the driver's uncomfortable feeling.

(Fourth embodiment)
The observation position P to be read ahead may be set based on the amount of change in the curvature ρ of the travel lane in addition to the acceleration upper limit value.

  FIG. 11 is a diagram for explaining the relationship between the amount of change in curvature ρ and the distance ΔL from the current position of the vehicle CS to the observation position P to be prefetched in the fourth embodiment. In the fourth embodiment, for example, the ECU 20 stores a map that defines the relationship between the amount of change in the curvature ρ of the travel lane and the distance ΔL. In this map, a value is stored so as to increase the distance ΔL as the amount of change in the curvature ρ increases. In step S14 of FIG. 3, the ECU 20 refers to this map and sets the observation position P to be prefetched.

  As described above, in the fourth embodiment, when setting the observation position P, the ECU 20 (position setting unit) changes the distance ΔL based on the change amount of the curvature ρ in the travel route. The greater the amount of change in the curvature ρ of the travel lane, the more rapid steering is required, and the greater the chance that the driver will feel uncomfortable. Therefore, by setting the observation position P to be prefetched based on the amount of change in the curvature ρ on the travel route, the driver's uncomfortable feeling can be suppressed.

(Other embodiments)
The method for acquiring the curvature ρ of the travel route is not limited to the captured image output from the camera device 31. In addition to this, in step S <b> 12 of FIG. 3, the ECU 20 may acquire the curvature ρ of the travel route based on the map information obtained from the navigation device 33.

  The use of lane marks for setting the driving lane is only an example. When the vehicle CS supports so-called ACC (Adaptive Cruise Control) that follows the traveling locus of the preceding vehicle, the traveling lane may be set based on the traveling locus of the preceding vehicle. In this case, in step S12 of FIG. 3, the ECU 20 acquires the travel path parameters (ρ, φ, Δy) of the vehicle CS based on the travel locus of the preceding vehicle.

  It is only an example that it is determined whether the vehicle CS is traveling on a curve or not traveling using the amount of change in the curvature ρ in the travel lane in step S13 in FIG. In addition to this, the ECU 20 may hold a flag for switching the observation position P between the current position and the forward position, and switch the observation position P by determining the flag in step S13.

  Further, in step S13 of FIG. 3, the ECU 20 obtains the curvature when the difference between the target steering amount M based on the curvature at the front position and the target steering amount M based on the curvature at the current position becomes small. May be changed from the forward position to the current position.

  The curve shape has a section where the curvature ρ is constant in the middle. Therefore, in the middle of the curve, the target steering amount M set by pre-reading the observation position P and the target steering amount M at the current position have the same value. Therefore, in step S13 of FIG. 3, the ECU 20 determines the difference between the target steering amount M at the front position and the target steering amount M at the current position. If the ECU 20 determines that the difference in the target steering amount M is small, the ECU 20 returns the observation position P to the current position of the vehicle CS. With the above configuration, when the vehicle CS travels in the middle of the curve, the target steering amount M can be set based on the curvature ρ corresponding to the current position of the vehicle CS, so that the vehicle CS travels at an appropriate position in the travel lane. Can do.

  Further, in step S13 of FIG. 3, the ECU 20 detects that the vehicle CS has entered the curve based on the information on the traveling lane acquired from the navigation device 33, and changes the flag to the observation position P after prefetching. There may be. Further, the ECU 20 calculates the time required for the vehicle CS to escape from the curve based on the travel lane information acquired from the navigation device 33, and when this time has elapsed, the flag is set to the current position in step S13. It may be returned.

  DESCRIPTION OF SYMBOLS 10 ... Steering control apparatus, 20 ... ECU, 40 ... Steering apparatus, 100 ... Driving assistance system

Claims (10)

A steering amount control device (20) that is applied to a steering device (40) that changes a steering amount of a vehicle and that acquires a target steering amount of the steering device based on a curvature of a travel route of the vehicle,
A position setting unit that sets a forward position in the vehicle traveling direction from the current position as a position for acquiring the curvature at the current position of the vehicle;
A steering amount control apparatus, comprising: a target steering amount acquisition unit that acquires the target steering amount based on the set curvature at the front position. An acceleration limiting unit that limits the acceleration of the target steering amount;
The steering amount control device according to claim 1, wherein the position setting unit sets the front position according to the acceleration.   The said position setting part sets the said front position as a position for acquiring the said curvature, when the variation | change_quantity of the curvature of the said driving | running route is more than predetermined value in the said vehicle advancing direction. Item 3. The steering amount control device according to Item 2. A direction detection unit that detects a direction of the vehicle with respect to the travel route;
The steering amount control device according to claim 2, wherein the acceleration limiting unit sets the limit value of the acceleration based on the detected direction of the vehicle with respect to the road.   The steering amount control device according to claim 2, wherein the position setting unit sets the front position farther in the vehicle traveling direction than the current position of the vehicle as the limit value of the acceleration is lower.   The steering amount control device according to any one of claims 1 to 5, wherein the position setting unit sets a distance from a current position of the vehicle to the front position based on a vehicle speed.   The steering according to any one of claims 1 to 5, wherein the position setting unit sets a distance from a current position of the vehicle to the front position based on an amount of change in curvature of the travel route. Quantity control device.   The position setting unit, after setting the target steering amount based on the curvature at the front position, a difference between the target steering amount based on the curvature at the front position and the target steering amount based on the curvature at the current position. The steering amount control device according to any one of claims 1 to 7, wherein a position at which the curvature is acquired is changed from the front position to the current position when the value of the steering angle decreases. A direction detecting unit for detecting a direction of the vehicle with respect to the travel route;
A position setting unit that sets a forward position in the vehicle traveling direction from the current position as a position for obtaining the curvature at the current position of the vehicle based on the detected direction of the vehicle with respect to the road; The steering amount control device according to claim 1, comprising: A steering amount control method that is applied to a steering device (40) that changes a steering amount of a vehicle and that obtains a target steering amount of the steering device based on a curvature of a travel route of the vehicle,
A position setting step of setting a forward position in the vehicle traveling direction from the current position as a position for acquiring the curvature at the current position of the vehicle;
And a target steering amount acquisition step of acquiring the target steering amount based on the set curvature at the front position.

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