JP5315769B2 - Steering device - Google Patents

Description

  The present invention relates to a steering apparatus that is configured to control an operation amount of an actuator in accordance with a situation of a road on which a vehicle travels so as to add an assisting force to a steering mechanism.

  A steering device that steers a vehicle is configured to transmit an operation of a steering member such as a steering wheel by a driver to a steering mechanism and operate the steering mechanism. In recent years, the steering mechanism is operated by an actuator on the basis of information such as the condition of the road on which the vehicle is traveling, the position of the vehicle in the traveling lane, the traveling state of the vehicle such as the vehicle speed, and the like. Various configured steering devices have been proposed. As such a steering device, for example, a road in the traveling direction of the vehicle is imaged by an imaging means such as a CCD camera, and a white line that defines a driving lane of the road on which the vehicle travels is detected from the captured image, and the driving lane There has been proposed a steering device configured to perform steering control so that traveling along the vehicle can be automatically performed. In addition, in response to a deviation from the driving lane of the vehicle or a prediction of the deviation, for example, when it is not the driver's conscious steering such as a lane change, a steering intervention is performed to prevent the deviation from the driving lane. An improved steering device has been proposed.

  In the steering device configured to perform such lane keeping control, the travel lane in which the vehicle travels and the position of the vehicle in the travel lane are detected based on the image captured by the imaging unit. The actuator is driven according to the shape of the traveling lane and the position of the vehicle, and the generated force of the actuator is applied to the steering mechanism to perform steering or steering support.

  By the way, the road on which the vehicle travels is provided with drainage grooves on both sides for draining rainwater, etc., and is generally inclined in the road width direction so that rainwater can easily flow into the drainage grooves. . When the vehicle is steered in a low road surface, the necessary steering torque applied to the steering member can be small, whereas when the vehicle is steered in a high road surface, the necessary steering torque is large. For this reason, when a vehicle is steered by lane keeping control, regardless of the height of the road surface in the steered direction, the driver may apply a force according to the distance from the white line of the traveling lane to the steering mechanism. There was a problem of giving a sense of incongruity.

In order to solve this problem, there has been proposed a steering device configured to detect the road surface inclination of the road at the current position of the vehicle and apply an assisting force corrected according to the detected road surface inclination to the steering mechanism. (For example, refer to Patent Document 1). With this configuration, the assisting force according to the distance from the white line of the traveling lane of the vehicle is corrected so as to increase or decrease according to the level of the road surface in the steering direction of the vehicle, and the assisting force corrected according to the road surface inclination is corrected. Since it is added to the steering mechanism, the lane keeping control of the vehicle can be performed without giving the driver a sense of incongruity.
JP 2007-106250 A

  However, in the steering apparatus described in Patent Document 1, the road surface inclination of the road at the current position of the vehicle is detected, and the position of the vehicle at the time when the assisting force according to the detection result is added to the steering mechanism is There is a problem that a control delay occurs because the position is advanced ahead of the position where the road surface inclination is detected.

  The present invention has been made in view of such circumstances, and a control delay is caused by detecting the road surface inclination of the road in the traveling direction of the vehicle and controlling the operation amount of the actuator in accordance with the detected road surface inclination. An object of the present invention is to provide a steering apparatus that can add an appropriate assisting force corrected according to the road surface inclination to the steering mechanism.

A steering apparatus according to a first aspect of the present invention includes a road condition detecting unit that detects a condition of a road on which a vehicle is traveling, and an actuator that is to apply an assisting force to the steering mechanism according to the road condition detected by the road condition detecting unit. in steering apparatus and control means for controlling the operation amount, the road condition detecting means includes imaging means for imaging the traveling direction of the road of the vehicle is provided in a central position in the vehicle width of the vehicle, image pickup means The posture holding means for holding the posture of the imaging means so that the vertical axis of the image taken by the camera always coincides with the direction of gravity , the white line located on the left and right of the center of the image taken by the imaging means, and the image Based on the angles α1, α2 and the distances L1, L2 between the central portion and the white line, and the distances L1, L2 detected by the image processing unit. α2 is corrected Based on the angular [alpha] 1, [alpha] 2 corrected, and a tilt calculation means for preliminarily calculating the road width direction of the road surface inclination of the traveling direction of the road, the control means, the imaging direction of travel and the imaging unit of the vehicle When the direction matches, the assisting force to be added to the steering mechanism is obtained according to the distance from the white line defining the road lane of the vehicle, and the obtained assisting force is calculated as the inclination. Correction means for correcting the vehicle so as to increase or decrease depending on the height of the road surface in the turning direction of the vehicle due to the road surface inclination calculated by the means, and to generate the assisting force corrected by the correction means, The operation amount is controlled.

In the steering apparatus according to the second aspect of the invention, the correction means calculates and calculates a correction amount that is maximized when the distance from the white line is 0 and increases in proportion to a decrease in the absolute value of the distance. The correction amount is multiplied by a gain that is small when the steered direction is a low direction on the road surface and large when the steering direction is a high direction, thereby correcting the correction amount, and the corrected correction amount is added to the assisting force. It is characterized by being added .

In the steering apparatus according to a third aspect of the present invention, the posture holding means swings the imaging means around a horizontal axis along the traveling direction of the vehicle, and inclination detecting means for detecting the inclination of the vehicle width direction of the vehicle with respect to the horizontal direction. Swinging means for moving the imaging means, wherein the swinging means is configured to swing the imaging means by the amount of the vehicle inclination detected by the tilt detection means.

According to the first invention, the road in the traveling direction of the vehicle is imaged, the road surface inclination in the width direction of the road in the traveling direction is calculated in advance based on the captured image, and the actuator is operated according to the road surface inclination calculated in advance. Therefore, an appropriate assisting force corresponding to the road surface inclination at the position can be added to the steering mechanism when the position is reached without any control delay. In addition, since the road condition detection unit has a posture holding unit that holds the posture of the imaging unit so that the vertical axis of the image captured by the imaging unit always matches the gravity direction, the image captured by the imaging unit Need not be corrected according to the attitude of the imaging means, in other words, the vehicle width direction inclination of the vehicle, and the processing of the inclination calculating means for calculating the road surface inclination can be simplified . Further, an assisting force to be added to the steering mechanism is obtained according to the distance from the white line that defines the vehicle lane, and the road surface in the steering direction of the vehicle due to the road surface inclination calculated by the inclination calculating unit is determined. The amount of movement of the actuator is controlled so as to generate the corrected assisting force by correcting the assisting force so as to become smaller and smaller, so by appropriately setting the correction amount of the assisting force (overlay torque) Even when the road surface is inclined, the movement of the vehicle is the same regardless of the steering direction, and the driver does not feel uncomfortable. Further, for example, when lane keeping control is performed during the steering of the driver, even when the road surface is inclined, the steering torque that the driver should apply to the steering member is the same regardless of the steering direction. Do n’t make the driver feel uncomfortable.

According to the second invention, the correction means calculates the correction amount which is maximized when the distance from the white line defining the travel lane is 0 and increases in proportion to the decrease in the absolute value of the distance. By multiplying the correction amount by a gain that is small when the turning direction is low on the road surface and large when it is high, the correction amount is corrected, and the corrected correction amount is added to the assisting force. , by appropriately setting the correction amount of the assisting force, when the road surface is also inclined, the movement of the vehicle is the same regardless of whether the steering direction, it is not necessary to give a sense of discomfort to the driver. Further, for example, when lane keeping control is performed during the steering of the driver, even when the road surface is inclined, the steering torque that the driver should apply to the steering member is the same regardless of the steering direction. Do n’t make the driver feel uncomfortable.

According to the third invention, the inclination of the vehicle in the vehicle width direction with respect to the horizontal direction is detected by the inclination detection means, and the imaging means is moved by the swinging means around the horizontal axis along the traveling direction of the vehicle by the detected inclination. Since it is oscillated, the posture of the imaging means can be maintained with a simple configuration of the inclination detecting means and the oscillating means.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof. FIG. 1 is a schematic diagram showing a configuration of a steering apparatus according to the present invention. A steering apparatus according to the present invention includes a rack shaft 10 that is supported so as to be movable in the axial direction in a rack housing 11 that extends in the left-right direction of a vehicle body (not shown), and a pinion that crosses the rack housing 11 in the middle. A rack and pinion type steering mechanism 1 having a pinion shaft 2 rotatably supported inside a housing 20 is provided.

  Both ends of the rack shaft 10 projecting outward from both sides of the rack housing 11 are connected to left and right front wheels 13 and 13 as steering wheels via separate tie rods 12 and 12, respectively. Further, the upper end of the pinion shaft 2 protruding outward from one side of the pinion housing 20 is connected to a steering wheel 30 as a steering member via the steering shaft 3.

  The steering shaft 3 is rotatably supported inside a cylindrical housing 31, and is attached to the interior of a passenger compartment (not shown) while maintaining a tilted posture with the front facing down via the housing 31. The pinion shaft 2 is connected to the projecting end of the steering shaft 3 downward, and the steering wheel 30 is fixed to the projecting end of the upward.

  With the above configuration, when the steering wheel 30 is rotated for steering, this rotation is transmitted to the pinion shaft 2 via the steering shaft 3, and the rotation of the pinion shaft 2 is engaged with the pinion and the rack. The movement of the rack shaft 10 is converted to the movement of the rack shaft 10 in the section, and such movement of the rack shaft 10 is transmitted to the left and right front wheels 13 and 13 via the separate tie rods 12 and 12 to steer. Made.

  In the middle of the housing 31 that supports the steering shaft 3, a torque sensor 4 that detects a steering torque applied to the steering shaft 3 by a rotation operation of the steering wheel 30 is provided.

  An electric motor 5 as an actuator is attached to the outside of the middle part of the rack housing 11. The output shaft of the electric motor 5 extends inside the rack housing 11 and is configured to be transmitted in the middle of the rack shaft 10 via a motion conversion mechanism such as a ball screw mechanism.

  The electric motor 5 attached in this way is driven in accordance with a control command given from the assist control unit 6 or the lane keep control unit 8 via the motor drive circuit 50. A detected value of the steering torque detected by the torque sensor 4 is given to the assist control unit 6. Further, the detected value of the vehicle speed detected by the vehicle speed sensor 7 disposed at an appropriate part of the vehicle is given to the assist control unit 6.

  The assist control unit 6 obtains a target auxiliary force using detection values obtained by the torque sensor 4 and the vehicle speed sensor 7, and performs an assist control operation for driving the electric motor 5 to generate the obtained target auxiliary force. This operation assists the steering performed as described above.

  A lane keep control unit 8 is connected to the assist control unit 6 so as to be communicable with each other, and the lane keep control is performed according to an operation of a lane keep control start switch (not shown) provided at an appropriate part in the vehicle interior. Control begins. The lane keep control unit 8 detects an output signal of an image captured by an in-vehicle camera 9 such as a CCD camera provided at an appropriate part of the vehicle to image a road in the traveling direction of the vehicle. The detected value of the vehicle speed is given respectively. As will be described later, the lane keeping control unit 8 performs a lane keeping control operation for driving the electric motor 5 so that the vehicle travels along the traveling lane of the road. The lane keep control unit 8 is configured to end the lane keep control operation when the steering torque becomes a certain value or more, or when a direction indicator (not shown) is operated.

  The in-vehicle camera 9 holds the posture so that the vertical axis of the image captured by the posture holding means 90 always coincides with the direction of gravity. FIG. 2 is a schematic diagram showing the configuration of the posture holding means 90 of the in-vehicle camera 9. A posture control motor 91 is attached to an appropriate part of the vehicle so that the output shaft of the posture control motor 91 coincides with the horizontal direction along the traveling direction of the vehicle. The output shaft of the attitude control motor 91 includes a first gear 92a provided coaxially with the output shaft and a second gear 92b having a different number of teeth meshing with the first gear 92a. Means 92 are provided. A vehicle-mounted camera 9 is coaxially attached to the center of the second gear 92b.

  The attitude control motor 91 is driven in accordance with a control command given from the attitude control unit 93 via a motor drive circuit (not shown). The attitude control unit 93 is given a detected value of the vehicle width direction inclination detected by a vehicle inclination sensor 94 provided at an appropriate part of the vehicle. As the vehicle tilt sensor 94, for example, a roll angle sensor, a gyro sensor, or the like is used. Since the roll angle sensor and the gyro sensor are known per se, detailed description thereof is omitted.

  The posture control unit 93 obtains a rotation amount necessary for rotating the in-vehicle camera 9 by the amount of the vehicle width direction tilt using the detection value of the vehicle tilt sensor 94, and takes the posture to obtain the calculated rotation amount. An attitude control operation for driving the control motor 91 is performed. By this operation, the attitude control motor 91 is rotated, and with this rotation, the first gear 92a provided on the output shaft of the attitude control motor 91 is rotated. The camera 9 rotates around the horizontal axis along the traveling direction of the vehicle. As a result, the posture of the in-vehicle camera 9 is vertical so that the vertical axis of the image captured by the in-vehicle camera 9 always coincides with the direction of gravity. Retained.

  FIG. 3 is a block diagram showing a configuration of the lane keep control unit 8. In FIG. 3, the lane keep control unit 8 is represented by functional blocks. However, the lane keep control unit 8 includes a CPU, a ROM, and a RAM connected by an internal bus, and follows a control program stored in the ROM. The ECU is configured as an ECU that performs the following lane keep control by the operation of the CPU.

  An output signal of an image captured by the in-vehicle camera 9 is given to the image processing unit 81 of the lane keep control unit 8. Since this image is captured by the in-vehicle camera 9 held in the vertical direction so that the vertical axis always coincides with the gravity direction, the vertical direction (vertical axis) of the captured image is the vertical direction (gravity direction). In addition, the horizontal direction (horizontal axis) coincides with the horizontal direction. FIG. 4 is an image of a road in the traveling direction, and is an image when the vehicle is traveling in the center of a traveling lane having no road surface inclination in the width direction.

  The image processing unit 81 performs a series of image recognition processing on the image data given by the in-vehicle camera 9, and recognizes a pair of white lines 100L and 100R provided on the road on which the vehicle travels to thereby recognize the travel lane 100. Is detected. In the image captured by the in-vehicle camera 9, the brightness difference between the road surface and the white lines 100L, 100R is large, so the white lines 100L, 100R defining the travel lane 100 can be detected relatively easily by edge detection or the like. The traveling lane 100 in front of the vehicle can be detected. The image processing unit 81 obtains two straight lines La1 and La2 (indicated by broken lines in FIG. 4) obtained by linear approximation of the detected white lines 100L and 100R.

  The image processing unit 81 has inclinations α1, α2 (indicated by broken lines La1, La2 in FIG. 4) with respect to the horizontal axis (the horizontal axis of the image) of the white lines 100L, 100R in the white lines 100L, 100R located on the left and right of the center portion O of the image. The angle formed by the horizontal axis of the image) and the distances L1 and L2 between the central portion O of the image and the white lines 100L and 100R (the distances between the central portion O of the image and the broken lines La1 and La2 in FIG. 4) are detected. In addition, since the distance from the vehicle of the center portion O of the image captured by the in-vehicle camera 9 is determined according to the installation position of the in-vehicle camera 9, the in-vehicle camera 9 has the center portion O of the image X (m) ahead of the vehicle. An image is provided in advance at an appropriate position of the vehicle, and the lane keep control unit 8 stores in advance that the central portion O of the image is an image X (m) ahead of the vehicle. Thus, the inclination information of the road surface ahead of the traveling direction X (m) of the vehicle, more specifically, the inclinations α1 and α2 of the white lines 100L and 100R with respect to the horizontal axis of the image and the distance L1 between the center O of the image and the white lines 100L and 100R. , L2 can be detected. As shown in FIG. 4, when the vehicle is traveling in the center of the driving lane 100 with no road surface inclination in the road width direction, the inclinations α1 and α2 of the white lines 100L and 100R with respect to the horizontal axis are equal, and the center portion O of the image And the distances L1 and L2 between the white lines 100L and 100R (straight lines La1 and La2) are also equal.

  The image processing unit 81 gives the road surface inclination calculation unit 82 inclinations α1 and α2 with respect to the horizontal axis of the detected white lines 100L and 100R. Further, the image processing unit 81 gives distances L1 and L2 between the center O of the detected image and the white lines 100L and 100R to the vehicle position determination unit 83. As will be described later, the vehicle position determination unit 83 obtains a deviation of the vehicle from the center of the travel lane 100 according to the distances L1 and L2, and determines the obtained deviation of the vehicle from the center of the travel lane 100 to the road surface inclination calculation unit 82. give.

  The road surface inclination calculation unit 82 has a road surface inclination map that shows the relationship between the inclinations α1 and α2 of the white lines 100L and 100R with respect to the horizontal axis and the road surface inclination β as shown in FIG. The horizontal axis in FIG. 5 indicates α1-α2, and the vertical axis indicates the road surface inclination β. As shown in FIG. 5, the road surface inclination map is set so as to increase in proportion to the increase of α1-α2. The road surface inclination β represents an angle formed with the horizontal axis. In the case of the downward slope in FIG. 4, the road inclination β is positive, and in the case of the downward slope in FIG. 4, the road inclination β is negative. It becomes.

  When the deviation of the vehicle from the center of the travel lane 100 given by the vehicle position determination unit 83 is 0, the road surface inclination calculation unit 82 uses the inclinations α1 and α2 given by the image processing unit 81 as they are, α1 -Α2 is obtained, and the obtained α1-α2 is applied to the road surface inclination map to calculate the road surface direction inclination β in the road width direction of the travel lane 100 X (m) ahead of the vehicle. As shown in FIG. 4, when the vehicle is traveling in the center of the traveling lane 100 having no road surface inclination in the road width direction, α1 = α2 and therefore the road surface inclination β is 0 °. FIG. 6 is an image of a road in the traveling direction, and is an image when the vehicle is traveling in the center of a traveling lane having a road surface slope in the road width direction. At this time, the in-vehicle camera 9 is held in such a manner that the vertical axis of the captured image always coincides with the direction of gravity, and the horizontal axis of the image is the same as when there is no road inclination even when the road surface is inclined. The inclinations α1 and α2 of the white lines 100L and 100R with respect to the horizontal axis change according to the road surface inclination. In the figure, the inclination α1 of the image of the left white line 100L with respect to the horizontal axis is smaller than the inclination α2 of the image of the right white line 100R with respect to the horizontal axis (α1 <α2), so α1−α2 becomes negative and the road surface inclination β Is also negative. The distances L1 and L2 between the center O of the image and the white lines 100L and 100R are equal.

  On the other hand, the vehicle position determination unit 83 determines the position of the vehicle in the travel lane 100 using the distances L1 and L2 between the central portion O of the image given by the image processing unit 81 and the white lines 100L and 100R. As shown in FIGS. 4 and 6, when the vehicle is traveling in the center of the traveling lane 100, the distances L1 and L2 between the central portion O of the image and the white lines 100L and 100R are equal (L1 = L2). FIG. 7 is an image of the road in the traveling direction, and is an image when the vehicle is traveling in a position near the white line 100R on the right side away from the center of the traveling lane having no road surface inclination in the road width direction. The inclination α1 of the left white line 100L with respect to the horizontal axis of the image is smaller than the inclination α2 of the right white line 100R with respect to the horizontal axis of the image (α1 <α2), and the distance between the center O of the image and the left white line 100L. L1 is larger than the distance L2 between the center O of the image and the white line 100R on the right side (L1> L2). When the vehicle is traveling in a position away from the center of the traveling lane 100 as described above, a difference occurs between the distances L1 and L2 between the central portion O of the image and the white lines 100L and 100R. When the vehicle is located from the center of the driving lane 100 to the white line 100R on the right side in the figure, L1-L2 is positive, and when the vehicle is from the center of the driving lane 100 to the position from the white line 100L on the left side in the figure. , L1-L2 becomes negative.

  The vehicle position determination unit 83 uses the value of L1−L2 as an indicator of the deviation from the center of the vehicle. For example, the relationship between the deviation from the center of the vehicle determined according to L1−L2 and the inclinations α1 and α2. Is obtained by using the distances L1 and L2 given by the image processing unit 81, and applying the obtained L1-L2 to the vehicle position deviation map. The deviation from the center of the traveling lane 100 is determined. As described above, the vehicle position determination unit 83 gives a deviation from the center of the travel lane 100 of the vehicle to the road surface inclination calculation unit 82.

  The road surface inclination calculation unit 82 corrects the inclinations α1 and α2 using the deviation of the vehicle from the center of the travel lane 100 given by the vehicle position determination unit 83, and uses the corrected inclinations α1 and α2 as described above. Then, a road surface inclination β in the road width direction X (m) ahead of the vehicle in the travel lane 100 is calculated. The road surface inclination calculation unit 82 gives the road surface inclination β thus calculated to the overlay torque map correction unit 84.

  The overlay torque map correction unit 84 has an overlay torque map showing the relationship between the distance from the white lines 100L and 100R of the vehicle and the overlay torque, as shown in FIG. The horizontal axis in FIG. 8 indicates the distance from the white lines 100L and 100R of the vehicle, the vertical axis indicates the overlay torque, the right side of the horizontal axis indicates the distance from the white line 100R on the right side of the vehicle, and the left side of the horizontal axis indicates the vehicle. The distance from the white line 100L on the left side of each is shown. As shown in FIG. 8, the overlay torque map increases in proportion to a decrease in the absolute value of the distance from the white lines 100L and 100R of the vehicle, and becomes maximum when the distance from the white lines 100L and 100R is zero. It is set as follows. As the distance from the white lines 100L and 100R of the vehicle, the distance between the two white lines 100L and 100R and the white line closer to the vehicle and the vehicle is used, and the overlay torque is the vehicle traveling along the travel lane 100. As described above, an assisting force that increases as the vehicle moves away from the center of the traveling lane 100 is added to the steering mechanism 1 in a direction in which the vehicle is steered toward the center. When the road lane 100 has no road surface inclination β in the road width direction, the overlay torque map has a symmetrical shape as shown by a solid line in FIG. 8, and overlays the white line 100R on the right side of the road lane 100 and the distance between vehicles. The torque is set so that the white line 100L on the left side of the traveling lane 100 and the overlay torque with respect to the distance between the vehicles are equal.

  On the other hand, the detected value of the vehicle speed detected by the vehicle speed sensor 7 is given to the moving distance integrating unit 85. The moving distance integrating unit 85 uses the vehicle speed given by the vehicle speed sensor 7 to integrate the moving distance of the vehicle after the time when the in-vehicle camera 9 images the road in the traveling direction and the vehicle speed multiplied by a minute time. By seeking. When the integrated value of the value obtained by multiplying the vehicle speed by the minute time becomes equal to X (m) corresponding to the central portion O of the image at the time when the road in the traveling direction is imaged by the in-vehicle camera 9. In addition, the operation command signal is supplied to the overlay torque map correction unit 84 and the vehicle position determination unit 83, respectively. The overlay torque map correcting unit 84 corrects the overlay torque map using the road surface inclination β given by the road surface inclination calculating unit 82 when the operation command signal is given by the movement distance integrating unit 85. This correction is performed by determining a gain G corresponding to the road surface inclination β, and multiplying the overlay torque map by the determined gain G. The gain G is determined so as to reduce the overlay torque when the turning direction of the vehicle is a low road surface and to increase the overlay torque when the vehicle is high in the road surface. As a result, the overlay torque map has a left-right asymmetric shape as indicated by a broken line in FIG. The example shown by a broken line in FIG. 8 is a case where the road surface is inclined so that the left road surface where the overlay torque increases when the turning direction of the vehicle is left becomes high. The overlay torque map correction unit 84 provides the torque determination unit 86 with the overlay torque map corrected in this way.

  The vehicle position determination unit 83 uses the distances L1 and L2 between the center O of the image and the white lines 100L and 100R given by the image processing unit 81 when the operation command signal is given by the movement distance integrating unit 85. The position of the vehicle in the travel lane 100, that is, the distance from the white lines 100L and 100R of the vehicle is determined. The vehicle position determination unit 83 gives the torque determination unit 86 the smaller value of the distances from the white lines 100L and 100R of the vehicle.

  The torque determination unit 86 applies the distances from the white lines 100L and 100R of the vehicle given by the vehicle position determination unit 83 to the corrected overlay torque map given by the overlay torque map correction unit 84, so that the steering mechanism The overlay torque to be added to 1 is determined. The torque determination unit 86 gives the determined overlay torque to the operation command output unit 87.

  The operation command output unit 87 gives the PWM signal generated to obtain the overlay torque given by the torque determination unit 86 to the motor drive circuit 50. The motor drive circuit 50 feeds / cuts off the electric motor 5 by an opening / closing operation according to the given PWM signal, and drives the electric motor 5. As a result, the overlay torque corresponding to the road surface inclination of the travel lane 100 in which the vehicle travels and the distance from the white lines 100L and 100R of the vehicle is added to the steering mechanism 1.

  FIG. 9 is a flowchart showing the contents of the overlay torque map correction operation of the lane keep control unit 8. The lane keeping control unit 8 takes in an output signal of an image captured by the in-vehicle camera 9 and a detected value of the vehicle speed detected by the vehicle speed sensor 7 at a predetermined sampling period (steps S1 and S2), and moves the vehicle. The distance is reset (step S3).

  Using the image captured in step S1, the inclinations α1, α2 of the white lines 100L, 100R with respect to the horizontal axis of the white lines 100L, 100R located on the left and right of the central portion O of the image are detected (step S4). Using the image captured in step S1, distances L1 and L2 between the central portion O of the image and the white lines 100L and 100R are detected (step S5). As described above, the inclinations α1 and α2 and the distances L1 and L2 are detected by the image processing unit 81.

  Next, L1-L2 is obtained using distances L1, L2 between the central portion O of the image detected in step S5 and the white lines 100L, 100R, and the vehicle is centered on the travel lane 100 from the obtained L1-L2 value. It is determined whether it is located in (step S6). When the vehicle is located at the center of the travel lane 100 (step S6: YES), the process proceeds to step S8. On the other hand, when the vehicle is not positioned at the center of the traveling lane 100 (step S6: NO), the horizontal lines of the white lines 100L and 100R are obtained using the deviation of the vehicle from the center of the traveling lane 100 given by the vehicle position determination unit 83. The inclinations α1, α2 with respect to the axes are corrected (step S7), and the process proceeds to step S8. As described above, whether or not the vehicle is located at the center of the travel lane 100 is determined by the vehicle position determination unit 83, and the correction of the inclinations α1 and α2 with respect to the horizontal axis of the images of the white lines 100L and 100R is performed by the road surface inclination calculation unit. At 82.

  Next, α1-α2 is obtained using the inclinations α1, α2 of the white lines 100L, 100R detected in step S4 with respect to the horizontal axis or the inclinations α1, α2 corrected in step S7, and the obtained α1-α2 is determined as the road surface. Applying to the inclination map, the road surface inclination β in the road width direction X (m) ahead of the vehicle in the travel lane 100 is calculated (step S8). As described above, the road surface inclination calculation unit 82 calculates the road surface inclination β in the road width direction of the travel lane 100.

  By integrating the value obtained by multiplying the vehicle speed by a minute time using the vehicle speed captured in step S2, the moving distance of the vehicle after the time point when the in-vehicle camera 9 images the road in the traveling direction is integrated (step S9). ). Next, it is determined whether or not the moving distance of the vehicle obtained in step S9 is X (m) (step S10). When the moving distance of the vehicle is X (m) (step S10: YES), the gain G corresponding to the road surface slope β calculated in advance in step S8 is determined, and the determined gain G is multiplied by the overlay torque map. The overlay torque map is corrected (step S11), and the overlay torque map correction operation is terminated. On the other hand, when the moving distance of the vehicle is less than X (m) (step S10: NO), the process returns to step S9 to repeat a series of operations. As described above, the total of the moving distance of the vehicle and the determination of whether or not the moving distance of the vehicle is X (m) are made in the moving distance integrating unit 85. As described above, the overlay torque map is corrected by the overlay torque map correction unit 84.

  The steering apparatus according to the present embodiment configured as described above captures the road in the traveling direction of the vehicle, and the road surface in the width direction of the traveling lane 100 ahead in the traveling direction X (m) based on the captured image. Since the inclination β is calculated in advance and the operation amount of the electric motor 5 is controlled according to the road surface inclination β calculated in advance, the position (X (m) ahead) is reached without control delay. Then, an appropriate overlay torque corresponding to the road surface inclination β at the position can be applied to the steering mechanism 1.

  In addition, an overlay torque map indicating the correspondence between the distance from the white lines 100L and 100R that define the vehicle lane 100 and the overlay torque to be added to the steering mechanism 1 is determined according to the level of the road surface in the steering direction of the vehicle. Therefore, even when the road surface is inclined, the movement of the vehicle is the same regardless of the steering direction, and the driver does not feel uncomfortable. I'm sorry. Further, for example, when lane keeping control is performed during the steering of the driver, even when the road surface is inclined, the steering torque that the driver should apply to the steering wheel 30 is the same regardless of the steering direction. Therefore, the driver does not feel uncomfortable.

  Since the posture of the vehicle-mounted camera 9 is held by the posture holding means 90 so that the vertical axis of the image captured by the vehicle-mounted camera 9 always coincides with the direction of gravity, the image captured by the vehicle-mounted camera 9 is There is no need to correct according to the inclination, and the processing of the lane keep control unit 8 for obtaining the road surface inclination β based on the captured image can be simplified. Further, the vehicle inclination sensor 94 detects the inclination of the vehicle in the vehicle width direction relative to the horizontal direction, drives the attitude control motor 91 by the detected inclination, and has the first gear 92a and the second gear 92b. By swinging the in-vehicle camera 9 via the motion transmitting means 92, the in-vehicle camera 9 is held in a posture so that the vertical axis of the image captured by the in-vehicle camera 9 always coincides with the direction of gravity. Therefore, the posture of the image pickup means can be held by a simple configuration of the vehicle tilt sensor 94 and the swing transmission means 92.

  In the present embodiment, the posture holding means 90 includes a posture control motor 91, a first gear 92a provided on the output shaft of the posture control motor 91, and a vehicle-mounted camera that meshes with the first gear 92a. And a swing transmission means 92 having a second gear 92b attached coaxially, and driving the attitude control motor 91 to rotate the in-vehicle camera 9 by the amount of inclination in the vehicle width direction of the vehicle. Thus, the in-vehicle camera 9 is configured to hold the posture so that the vertical axis of the image captured by the in-vehicle camera 9 always coincides with the direction of gravity. However, the present invention is not limited to this, and the in-vehicle camera 9 can be held. Any configuration may be used. For example, by providing a horizontal base suspended so as to be able to swing around a horizontal axis along the traveling direction of the vehicle, and installing an in-vehicle camera on the horizontal base, the horizontal base and the in-vehicle camera swing by their own weight. You may comprise so that the attitude | position of a vehicle-mounted camera may be hold | maintained.

  In the present embodiment, the overlay torque to be added to the steering mechanism 1 is determined using an overlay torque map indicating the relationship between the distance from the white lines 100L and 100R of the vehicle and the overlay torque. However, the present invention is not limited to this. Instead, the overlay torque may be determined using a reference table indicating the relationship between the distance from the white lines 100L and 100R of the vehicle and the overlay torque. The same applies to the road surface inclination map and the vehicle position deviation map.

  In the present embodiment, the assist control is switched to the lane keep control according to the operation of the lane keep control start switch. However, the present invention is not limited to this, and the vehicle deviates from or departs from the travel lane. In response to the prediction, for example, when it is not the driver's conscious steering such as lane change, a steering intervention may be automatically performed to prevent deviation from the traveling lane.

  Furthermore, in the present embodiment, the assist control unit 6, the lane keep control unit 8, and the attitude control unit 93 are configured separately, but the present invention is not limited thereto, and may be configured as one or two ECUs. .

  In the above embodiment, the steering device configured to perform the lane keeping control has been described, but the present invention is not limited to this. FIG. 10 is a schematic diagram showing a configuration of a steering apparatus according to another embodiment of the present invention.

  The assist control unit 6 is provided with a detected value of the steering torque detected by the torque sensor 4 and a detected value of the vehicle speed detected by the vehicle speed sensor 7, respectively. Further, the assist control unit 6 is given an output signal of an image captured by an in-vehicle camera 9 provided at an appropriate part of the vehicle so as to image a road in the traveling direction of the vehicle. Since other configurations are the same as those in the embodiment shown in FIG. 1, the same reference numerals as those in FIG. 1 are given to corresponding components, and detailed descriptions of the configurations and operations are omitted.

  The assist control unit 6 obtains the target auxiliary force using the detection values of the torque sensor 4 and the vehicle speed sensor 7, and uses the obtained target auxiliary force in the road surface direction in the steering direction of the vehicle according to the road surface inclination β in the road width direction of the traveling lane. An assist control operation is performed to drive the electric motor 5 so as to generate the corrected target assist force by correcting the target assist force so as to increase or decrease depending on the height of the target assist force. The concept of calculating the road surface inclination β and correcting the target auxiliary force using the calculated road surface inclination β is the calculation of the road surface inclination β and the overlay torque correction using the calculated road surface inclination β according to the above-described embodiment. Since it is the same as the idea, the description is omitted.

  In the steering apparatus configured as described above, the road in the traveling direction of the vehicle is imaged, and the road surface inclination β in the road width direction of the traveling lane ahead in the traveling direction X (m) is calculated in advance based on the captured image. Then, the electric motor 5 is corrected so as to generate the corrected target auxiliary force by correcting the target auxiliary force according to the road surface inclination β calculated in advance so that the target auxiliary force is increased or decreased according to the level of the road surface in the turning direction of the vehicle. Therefore, the steering mechanism 1 can provide an appropriate assisting force according to the road surface inclination β at the position when the position (X (m) ahead) is reached without any control delay. Can be added to. Even when the road surface is inclined, the steering torque that the driver should apply to the steering wheel 30 is the same regardless of the turning direction, and the driver does not feel uncomfortable.

  The steering device shown in FIGS. 1 and 10 is configured as a rack-assist type electric power steering device in which the motor is provided outside the rack housing 11 so that the output shaft of the electric motor 5 forms an angle with the rack shaft 10. However, it is not limited to this. It may be configured as a rack assist type electric power steering device in which an electric motor is provided outside the rack housing 11 so that the output shaft of the electric motor is parallel to the rack shaft 10, or coaxial with the rack shaft 10. Alternatively, a rack assist type electric power steering apparatus in which a steering assist motor is provided inside the rack housing 11 may be used. Further, it may be configured as a column assist type electric power steering device in which an electric motor is attached to the outside of the column housing 31 and is configured to transmit to the steering shaft 3, or generation of a hydraulic cylinder attached to the steering mechanism 1 is generated. You may comprise as a hydraulic power steering device which assists steering by force.

  Furthermore, it goes without saying that the present invention can be implemented in variously modified forms within the scope of the matters described in the claims.

It is a mimetic diagram showing composition of a steering device concerning the present invention. It is a schematic diagram which shows the structure of the attitude | position holding means of a vehicle-mounted camera. It is a block diagram which shows the structure of a lane keep control part. It is an image when the vehicle is traveling in the center of a travel lane with no road surface inclination in the road width direction. It is a road surface inclination map which shows the relationship between the inclination of a white line, and a road surface inclination. It is an image when the vehicle is traveling in the center of a traveling lane having a road surface slope in the road width direction. It is an image when the vehicle is traveling at a position near the white line on the right side away from the center of the traveling lane having no road surface inclination in the road width direction. It is an overlay torque map. It is a flowchart which shows the content of the overlay torque map correction | amendment operation | movement of a lane keep control part. It is a schematic diagram which shows the structure of the steering device which concerns on other embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Steering mechanism, 5 Electric motor (actuator), 8 Lane keep control part (Inclination calculation means, control means), 9 Car-mounted camera (Imaging means, Road condition detection means), 91 Attitude control motor (Oscillation means, Attitude) Holding means, road condition detection means), 92 swing transmission means (swing means, posture holding means, road condition detection means), 94 vehicle tilt sensor (tilt detection means, posture holding means, road condition detection means)

Claims (3)

Road condition detection means for detecting the condition of the road on which the vehicle travels, and control means for controlling the operation amount of the actuator to which the assisting force should be added to the steering mechanism according to the road condition detected by the road condition detection means; A steering apparatus comprising:
The road condition detection means is provided at a central position of the vehicle width of the vehicle and picks up an image of the road in the traveling direction of the vehicle, and the vertical axis of the image taken by the imaging means always coincides with the direction of gravity. In this way, the posture holding means for holding the posture of the imaging means, the angles α1, α2 formed by the white line located on the left and right of the central portion of the image captured by the imaging means and the horizontal axis of the image, and the central portion An image processing unit for detecting the distances L1 and L2 between the white line and the distances L1 and L2 detected by the image processing unit , correcting the angles α1 and α2, and based on the corrected angles α1 and α2. Inclination calculating means for calculating in advance the road surface inclination in the width direction of the road in the traveling direction, and the control means is configured to detect the vehicle when the traveling direction of the vehicle coincides with the imaging direction of the imaging means . Define the road lane The assisting force to be applied to the steering mechanism is obtained according to the distance from the white line, and the obtained assisting force is determined by the level of the road surface in the turning direction of the vehicle by the road surface inclination calculated by the inclination calculating unit. And a correction unit that corrects the magnitude of the actuator according to the control unit, and the operation amount of the actuator is controlled so as to generate the assisting force corrected by the correction unit.   The correction means calculates a correction amount that is maximum when the distance from the white line is 0, and increases in proportion to a decrease in the absolute value of the distance, and the turning direction is calculated based on the calculated correction amount. The correction amount is corrected by multiplying by a gain that is small when the road surface is in the low direction and large when the road surface is in the high direction, and the corrected correction amount is added to the assisting force. The steering apparatus according to claim 1. The posture holding means includes an inclination detecting means for detecting an inclination of the vehicle in the vehicle width direction with respect to a horizontal direction, and an oscillating means for oscillating the imaging means about a horizontal axis along the traveling direction of the vehicle. 3. The steering apparatus according to claim 1, wherein the swinging unit is configured to swing the imaging unit by an amount corresponding to a vehicle tilt detected by the tilt detection unit.

Images