JP6348285B2 - Steering control device - Google Patents

Description

  The present invention relates to a steering control device that performs steering control of a vehicle.

  Conventionally, a steering control device that performs steering control of a vehicle based on a captured image of a camera mounted on the vehicle is known (see, for example, Patent Document 1). This conventional steering control device detects the left and right white lines of the host vehicle lane, which is the lane in which the vehicle is traveling, from the captured image of the camera, and sets the target position of the future host vehicle based on the detected white line Then, steering control is performed so that the vehicle advances to the set target position.

JP 2005-145402 A

  By the way, if you are driving in an overtaking lane and the driver is unable to drive, such as when the driver is asleep or suddenly ill, you can change the lane by automatic steering, It is conceivable to stop the vehicle in the area.

  However, as a camera used for the steering control device, a camera with a narrow viewing angle is used in order to increase the resolution in the forward direction of the vehicle. In such a camera, since it is not possible to detect the left and right white lines of the lane change target lane that is an adjacent lane for which the lane is changed, there is a problem that the target position cannot be set appropriately when the lane change is performed. is there. Even if a radar is used instead of the camera, there is a similar problem.

  Accordingly, an object of the present invention is to provide a steering control device that can appropriately set a target position for changing lanes even when the left and right lane markings of the lane change target lane cannot be detected. To do.

  A steering control device according to the present invention is a steering control device that changes the lane of a vehicle by performing steering control of the vehicle, and includes a lane line detection unit that detects left and right lane lines of a lane ahead of the traveling direction of the vehicle, Steering that performs steering control of the vehicle from the left and right lane markings of the lane detected by the line detection unit toward the target position setting unit that sets the future target position of the vehicle and the target position set by the target position setting unit A target position setting unit when a lane change is made from a vehicle lane that is a lane in which the vehicle is traveling to a lane change target lane that is a lane adjacent to the vehicle lane. The lane width of the host vehicle lane is calculated from the left and right lane lines of the host vehicle lane detected by the lane detector, and the lane width of the host vehicle lane is calculated from the lane line on the lane change target lane side of the host vehicle lane. On a line that is approximately half the distance away, the target To set the location.

  According to the steering control device according to the present invention, if the lane marking detection unit detects the left and right lane markings of the lane, the lane width can be calculated by calculating the distance between the left and right lane markings. And it is estimated that the own vehicle travel lane and the lane change target lane have substantially the same lane width. Therefore, when changing the lane from the own vehicle lane to the lane change target lane, first, the lane width of the own vehicle lane is calculated from the left and right lane lines detected by the lane line detector. Then, a target position for lane change is set on a line that is separated from the lane line on the lane change target lane side of the own vehicle travel lane by a distance approximately half the lane width of the own vehicle travel lane. Thus, even if the left and right lane lines of the lane change target lane cannot be detected by the lane line detection unit, the target position for changing the lane can be appropriately set. Steering control for changing lanes can be performed.

  In this case, when the vehicle crosses the lane line on the lane change target lane side of the host vehicle lane, the target position setting unit sets the target position on a line passing through the center of the left and right lane lines detected by the lane line detection unit. Can be set. When the lane change is exceeded due to the lane change, the lane line detection unit detects the lane lines on the left and right of the lane change target lane. Therefore, when the lane line on the side where the lane change is performed is exceeded, the target position is set on a line passing through the center of the left and right lane lines detected by the lane line detection unit. Thereby, the setting accuracy of the target position can be increased.

  According to the present invention, it is possible to appropriately set a target position for changing lanes even when left and right lane markings in a lane change target lane cannot be detected.

It is a block diagram which shows schematic structure of the steering control apparatus which concerns on embodiment. It is a figure for demonstrating the deviation | shift amount of the target position in a vehicle of a different vehicle type. It is a figure which shows the control logic for calculating a target steering angle. It is a flowchart which shows the processing operation of a steering control apparatus. It is a figure which shows the state of a lane change. It is a figure which shows the state of a lane change. It is a figure which shows the state of a lane change. It is a figure which shows the state of a lane change.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

  The steering control device according to the present embodiment is mounted on a vehicle and performs steering control of the vehicle on behalf of the driver or as driving assistance for the driver when the driver becomes unable to drive due to a sudden illness or the like. Is changed to the lane on the shoulder side (lane change). The lane in which the vehicle is traveling before the lane change is called the “own vehicle lane”. The lane is adjacent to the own vehicle lane, and the vehicle travels after the lane change from the own vehicle lane. The lane to be changed (lane to be changed) is called “lane change target lane”.

  FIG. 1 is a block diagram illustrating a schematic configuration of the steering control device according to the embodiment. As shown in FIG. 1, the steering control device 1 according to the embodiment is a device that performs steering control of a vehicle by performing rotational drive control of the steering system 2, and includes a lane marking detection unit 3 and a motion information acquisition unit 4. And a control unit 5.

  In the steering system 2, a steering wheel 23 on which a driver performs a steering operation is connected to a steering shaft 22 connected to a gear box 21 connected to a steering wheel. The steering shaft 22 can be rotationally driven by the rotational drive device 24. The rotation drive device 24 is configured by an electric motor such as a motor. The rotational drive device 24 and the steering shaft 22 are connected by a gear mechanism such as a planetary gear, and the steering shaft 22 can be rotationally driven by the rotational drive device 24. In FIG. 1, the rotational drive device 24 is disposed immediately below the steering wheel 23, but the rotational drive device 24 may be disposed in the vicinity of the gear box 21 due to space or the like.

  The lane marking detection unit 3 detects left and right lane markings in the lane ahead of the vehicle in the traveling direction. The lane marking is a line such as a white line that divides the lane. When the lane marking detection unit 3 detects the lane marking, the lane marking detection unit 3 acquires information on the detected lane marking. The lane marking information can be represented by coordinate information on the coordinate axis centered on the host vehicle. Although the mounting position of the lane marking detection unit 3 is not particularly limited, the lane marking ahead in the traveling direction of the vehicle can be appropriately acquired by mounting it on the front end of the vehicle. As the lane marking detection unit 3, an imaging device such as a camera or various radars such as a millimeter wave radar can be used. When an imaging device is used as the lane marking detection unit 3, the lane marking detection unit 3, for example, analyzes image data captured by the imaging device, extracts a lane line, and extracts coordinate information ( Lane line information) can be acquired. When a radar is used as the lane marking detection unit 3, the lane marking detection unit 3, for example, can detect a lane marking by the radar and acquire coordinate information (division line information) from the extracted lane marking. . In the following description, a case where an imaging device is used as the lane marking detection unit 3 will be described. And if the lane marking detection part 3 detects the lane marking on either side of the lane ahead of the advancing direction of a vehicle, it will transmit the information of the detected lane marking to the control part 5.

  The exercise information acquisition unit 4 acquires vehicle exercise information. The motion information acquisition unit 4 acquires speed and yaw rate generated in the vehicle as motion information. The exercise information acquisition unit 4 may acquire information other than speed and yaw rate as exercise information. The vehicle speed can be obtained, for example, by detecting the rotational speed of each wheel and calculating the vehicle speed from the rotational speed of each wheel. As the yaw rate, the yaw rate generated in the vehicle can be obtained by the yaw rate sensor. Then, the exercise information acquisition unit 4 transmits the acquired exercise information to the control unit 5.

  The control unit 5 performs rotation drive control of the rotation drive device 24 of the steering system 2 based on information transmitted from the lane marking detection unit 3 and the motion information acquisition unit 4. Therefore, the control unit 5 includes functions of a lane change determination unit 51, a target position setting unit 52, an estimated position calculation unit 53, and a steering control unit 54. The control unit 5 is mainly configured by an arithmetic device such as a CPU and a storage device such as a memory, and performs various controls according to various programs stored in advance.

  The lane change determination unit 51 has a function of determining whether or not to change the lane of the vehicle by vehicle steering control. An example of a case where the vehicle lane is changed by the steering control of the vehicle includes a case where the driver cannot drive due to a sudden illness or the like while traveling in the overtaking lane. Whether the driver is unable to drive due to sudden illness or the like is based on, for example, the operation of an emergency button installed in the driver's seat or front passenger seat, and the driver's face image captured by a camera installed in the passenger compartment Judgment can be made based on the analysis results. Whether the vehicle is traveling in the overtaking lane is, for example, whether the distance to the road shoulder is a predetermined distance or more, and the current position detected by the GPS mounted on the vehicle is the overtaking lane on the map information Or not. For the distance to the road shoulder, for example, the distance to the guardrail or curb is detected by an imaging device such as a camera or various radars such as millimeter wave radar, and the detected distance to the guardrail or curb is used as the distance to the road shoulder. Can be obtained.

  The target position setting unit 52 has a function of setting a target position of a future vehicle for changing the lane of the vehicle by steering control of the vehicle based on the lane line acquired by the lane line detection unit 3. The future target position of the vehicle may be, for example, the target position of the vehicle after a predetermined time (after τ time) or the target position of the vehicle after the lane change is completed.

Here, the target position set by the target position setting unit 52 will be described in detail. Until the vehicle crosses the lane line on the lane change target lane side of the own vehicle lane (while traveling in the own vehicle lane), the lane line detection unit 3 detects the left and right lane lines of the own vehicle lane . On the other hand, when the vehicle changes lanes and crosses the lane line (enters the lane change target lane ) , the lane line detection unit 3 detects the left and right lane lines of the lane change target lane. For this reason, it is possible to detect the lane line on the lane change target lane side among the left and right lane lines of the lane change target lane until the vehicle exceeds the lane line on the lane change target lane side of the own vehicle lane. The lane marking on the opposite side of the lane cannot be detected.

  Therefore, until the vehicle crosses the lane line, the target position setting unit 52 sets the target position in the lane change target lane based on the information on the left and right lane lines of the host vehicle lane detected by the lane line detection unit 3. . Specifically, the target position setting unit 52 first acquires information on the left and right lane lines of the host vehicle travel lane from the lane line detection unit 3, and the host vehicle travel lane from the acquired information on the left and right lane lines. The own vehicle traveling lane width which is the lane width of the vehicle is calculated. Further, the target position setting unit 52 selects a lane line on the lane change target lane side as a lane change side lane line from the left and right lane lines of the host vehicle travel lane acquired by the lane line detection unit 3. In addition, the target position setting unit 52 calculates a line that is separated from the lane change-side lane line by a distance that is substantially half the width of the host vehicle travel lane as the central predicted line. “Half half” means substantially half and includes half. Then, the target position setting unit 52 sets the target position on the calculated central predicted line.

  On the other hand, when the vehicle crosses the lane line, the target position setting unit 52 sets the target position in the lane change target lane based on the information on the left and right lane lines of the lane change target lane detected by the lane line detection unit 3. . More specifically, the target position setting unit 52 first acquires information on the left and right lane lines of the lane change target lane from the lane line detection unit 3, and from the acquired information on the left and right lane lines, Calculate the center line through the center of the line. Then, the target position setting unit 52 sets the target position on the calculated center line.

  The estimated position calculation unit 53 has a function of calculating an estimated position of a future vehicle based on the current vehicle movement information acquired by the movement information acquisition unit 4. The estimated position of the future vehicle is the estimated position of the vehicle after a predetermined time (after τ time), like the target position of the future vehicle, and may be the estimated position of the vehicle after 5 seconds, for example. it can.

Here, as shown in FIG. 2, a coordinate axis is considered in which the vehicle longitudinal direction is the x-axis and the direction orthogonal to the x-axis (the vehicle lateral direction) is the y-axis. Further, the vehicle speed V, the yaw rate gamma, the estimated position of the vehicle after τ seconds in the y-axis direction and y _t, the estimated position of the vehicle after τ seconds in the x-axis direction l _t. Then, when the estimated position calculation unit 53 acquires the vehicle speed and the yaw rate as the vehicle motion information from the motion information acquisition unit 4, the estimated position calculation unit 53 calculates the following equations (1) and (2) to calculate the vehicle position after τ seconds. and it calculates the estimated position _{y t} and the estimated position _{l t.} Incidentally, the calculated estimated position y _t and the estimated position l _t is the estimated position of the vehicle after τ seconds.

y _t = τ ² · V · γ (τ) / 2 (1)
l _t = τ · V (2)
The steering control unit 54 has a function of performing steering control of the vehicle based on a deviation amount (difference) between the target position and the estimated position. That is, the steering control unit 54 performs steering control of the vehicle based on the deviation amount ε (see FIG. 2) between the target position set by the target position setting unit 52 and the estimated position calculated by the estimated position calculating unit 53.

  FIG. 3 is a diagram showing a control logic for performing steering control of the vehicle. As shown in FIG. 3, the steering control unit 54 includes a PID control unit 56 that performs PID (Proportional Integral Derivative) control, and a drive command unit 57 that performs rotation drive control of the rotation drive device 24 of the steering system 2. ing.

  The PID control unit 56 includes a P term 56a that performs proportional control (P control), an I term 56b that performs integral control (I control), and a D term 56c that performs differential control (D control). The PID control unit 56 calculates a target steering angle that is a steering angle that should be a target by PID control based on a deviation amount between the target position and the estimated position, and calculates a deviation amount between the current steering angle and the target steering angle. . Then, the steering control unit 54 outputs a command for rotationally driving the rotary drive device 24 from the drive command unit 57 when the amount of deviation between the current steering angle and the target steering angle is equal to or greater than a predetermined threshold. As the PID control unit 56, a known control device that performs PID control can be used.

  Here, the rotation drive control of the rotation drive device 24 includes a case where a rotation angle is commanded and a torque is commanded. In either case, a command is output when the amount of deviation is equal to or greater than a predetermined threshold value. However, when the rotation angle is commanded, the threshold value can be made smaller than when torque is commanded. For example, when commanding the rotation angle, the threshold value of the deviation amount is ± 100 mm, and when commanding the torque, the threshold value of the deviation amount is ± 200 mm.

  When a command is output from the drive command unit 57 to the rotational drive device 24, the rotational drive device 24 is rotationally driven to rotate the steering shaft 22 and perform automatic steering. The estimated position calculation unit 53 performs τ seconds. A later estimated position is calculated.

  Next, the processing operation of the steering control device 1 will be described with reference to FIG. FIG. 4 is a flowchart showing the processing operation of the steering control device.

  As shown in FIG. 4, the control unit 5 first determines whether or not to change the lane of the vehicle by the steering control of the vehicle (step S1). The processing in step S1 is performed by the lane change determination unit 51. And when it determines with not changing a lane by a vehicle steering control (step S1: NO), the steering control apparatus 1 complete | finishes a process.

  On the other hand, if it is determined that the lane of the vehicle is to be changed by the steering control of the vehicle (step S1: YES), the control unit 5 obtains information on the left and right lane lines of the lane in the forward direction of the vehicle acquired by the lane line detection unit 3. While acquiring (step S2), the exercise | movement information of the vehicle which the exercise | movement information acquisition part 4 acquired is acquired (step S3). The process of step S2 is performed by the target position setting unit 52, and the process of step S3 is performed by the estimated position calculation unit 53. The lane for detecting the left and right lane lines in step S2 is the own vehicle lane until the vehicle crosses the lane line, and becomes the lane change target lane when the vehicle crosses the lane line. Note that either step S2 or step S3 may be processed first or in parallel.

  Next, the control part 5 determines whether it exceeded the lane change side lane marking (step S4). The process of step S4 is performed by the target position setting unit 52. Whether or not the vehicle has crossed the lane line is, for example, whether or not the current position detected by the GPS mounted on the vehicle has crossed the lane line on the map information, or left and right detected by the lane line detection unit 3 It can be judged by whether or not the lane marking has changed.

  If it is determined that the lane change side lane line is not exceeded (step S4: NO), the control unit 5 sets a target position in the lane change target lane based on information on the left and right lane lines of the host vehicle lane. (Step S5). The process of step S5 is performed by the target position setting unit 52. In step S5, first, the host vehicle travel lane width is calculated from the information on the left and right lane markings of the host vehicle travel lane acquired in step S2. Next, a central predicted line that is separated from the lane change side lane line by a distance that is approximately half the width of the host vehicle traveling lane is calculated. Then, the target position is set on the calculated central predicted line.

  When it is determined that the vehicle has crossed the lane change side lane line (step S4: YES), the control unit 5 sets a target position in the lane change target lane based on information on the left and right lane lines of the lane change target lane. (Step S6). The process of step S6 is performed by the target position setting unit 52. In step S6, first, a center line passing through the center of the left and right lane lines is calculated from the information on the left and right lane lines of the lane change target lane acquired in step S2. Then, the target position is set on the calculated center line.

  Next, the control unit 5 calculates the estimated position of the future vehicle based on the vehicle motion information acquired in step S2 (step S7). The process of step S7 is performed by the estimated position calculation unit 53.

  Next, the control unit 5 calculates a target steering angle based on the target position set in step S5 or step S6 and the estimated position calculated in step S7, and calculates a deviation amount between the current steering angle and the target steering angle. Calculate (step S8). The process of step S8 is performed by the steering control unit 54.

  Next, the control unit 5 determines whether or not the amount of deviation calculated in step S8 is greater than or equal to a predetermined threshold (step S9). The process of step S9 is performed by the steering control unit 54.

  When it is determined that the amount of deviation is greater than or equal to the predetermined threshold (step S9: YES), the control unit 5 rotationally drives the rotation drive device 24 (step S10). The process of step S10 is performed by the steering control unit 54. Then, the processing operation of the steering control device 1 is once terminated and repeated from step S1 again.

  On the other hand, when it is determined that the amount of deviation is less than the predetermined threshold (step S9: NO), the control unit 5 temporarily ends the processing operation of the steering control device 1 without rotationally driving the rotational drive device 24, Repeat from step S1 again.

  Here, the lane change operation of the vehicle by the steering control device 1 will be described with reference to FIGS. 5-8 is a figure which shows the state of a lane change. 5 to 8, the vehicle V is changed from the own vehicle traveling lane A divided by the left lane line L1 and the right lane line L2 to the lane change divided by the left lane line L3 and the right lane line L1. The state where the lane is changed to the target lane B is shown. For this reason, the lane marking L1 becomes the lane change side lane marking.

  As shown in FIG. 5, before the processing of the present embodiment is performed, steering control for performing lane keeping of the vehicle V is performed with the center line C of the host vehicle travel lane A as the target position O. In addition, well-known control can be used for the steering control which performs the lane keeping of the vehicle V. FIG.

  When the vehicle V changes its lane from the own vehicle lane A to the lane change target lane B, first, as shown in FIG. 6, the lane line L1 and the lane line L2 of the own vehicle lane A detected by the lane line detection unit 3 are detected. The lane width of the own vehicle travel lane A is calculated from the above, and the target position O is set on the central predicted line C ′ that is separated from the lane marking L1 by a distance approximately half the lane width of the own vehicle travel lane A. Then, steering control is performed to change the lane of the vehicle V toward the set target position O.

  When the vehicle V exceeds the lane marking L1, as shown in FIG. 7, the center of the lane change target lane B calculated from the lane marking L3 and the lane marking L1 of the lane change target lane B detected by the lane marking detection unit 3 A target position O is set on the line C. Then, until the vehicle V reaches the center line C, the steering control for changing the lane of the vehicle V toward the set target position O is performed.

  When the lane change of the vehicle V is completed, as shown in FIG. 8, the center line of the lane change target lane B calculated from the lane line L3 and the lane line L1 of the lane change target lane B detected by the lane line detection unit 3 A target position O is set on C. Then, steering control is performed to keep the lane of the vehicle toward the set target position O.

  Thus, according to the present embodiment, if the lane marking detector 3 detects the lane markings on the left and right of the lane, the lane width can be calculated by calculating the distance between the lane markings on the left and right. And it is estimated that the own vehicle travel lane and the lane change target lane have substantially the same lane width. Therefore, when changing the lane from the own vehicle lane to the lane change target lane, first, the lane width of the own vehicle lane is calculated from the left and right lane lines detected by the lane line detection unit 3. Then, a target position for lane change is set on the central predicted line that is separated from the lane change side lane by a distance approximately half the lane width of the host vehicle lane. Thus, even if the left and right lane lines of the lane change target lane cannot be detected by the lane line detection unit 3, the target position for changing the lane can be appropriately set. Steering control for changing the lane of the vehicle can be performed.

  Moreover, when the lane change side lane line is exceeded by the lane change, the lane line detection unit 3 detects the left and right lane lines of the lane change target lane. Therefore, when the lane change side lane line is exceeded, the target position is set on the center line passing through the center of the left and right lane lines detected by the lane line detection unit 3. Thereby, the setting accuracy of the target position can be increased.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  For example, in the above embodiment, the specific configurations of the lane line detection unit and the motion information acquisition unit have been described. However, the lane line detection unit and the motion information acquisition unit may have any configuration as long as they can acquire the lane line and the motion information, respectively. May be.

  In the above embodiment, the specific control mode of the steering control unit has been described. However, the steering control unit may be any control mode as long as the vehicle can perform steering control based on the difference between the target position and the estimated position. May be.

  In the above embodiment, the description has been made assuming that all functions are realized by one control device. However, these functions may be realized by a plurality of control devices, and one function is realized by a plurality of control devices. May be.

  In the above embodiment, the processing operation of the steering control device has been specifically described. However, the processing order of each step can be changed as appropriate, and for example, the processing order of each step may be changed as appropriate. These steps may be performed in parallel.

  DESCRIPTION OF SYMBOLS 1 ... Steering control apparatus, 2 ... Steering system, 3 ... Marking line detection part, 4 ... Motion information acquisition part, 5 ... Control part, 21 ... Gear box, 22 ... Steering shaft, 23 ... Steering wheel, 24 ... Rotation drive device , 51 ... Lane change determination section, 52 ... Target position setting section, 53 ... Estimated position calculation section, 54 ... Steering control section, 56 ... PID control section, 56a ... P term, 56b ... I term, 56c ... D term, 57 ... Drive command section.

Claims (6)

A steering control device that performs steering control of a vehicle to change the lane of the vehicle,
A lane marking detector that detects left and right lane markings in the lane ahead of the vehicle in the traveling direction;
A target position setting unit that sets a future target position of the vehicle from left and right lane markings of the lane detected by the lane marking detection unit;
A steering control unit that performs steering control of the vehicle so as to go to the target position set by the target position setting unit;
With
When changing the lane from the own vehicle travel lane that is the lane in which the vehicle is traveling to the lane change target lane that is the lane adjacent to the own vehicle travel lane, the target position setting unit is the lane marking detection unit The lane width of the host vehicle lane is calculated from the left and right lane lines of the host vehicle lane detected by the vehicle lane, and the host vehicle lane is calculated from the lane line on the lane change target lane side of the host vehicle lane. Set the target position on a line separated by a distance approximately half of the lane width ,
When the vehicle crosses the lane marking on the lane change target lane side of the host vehicle lane, the target position setting unit is on a line passing through the center of the left and right lane markings detected by the lane marking detection unit. Setting the target position ;
Steering control device.   An exercise information acquisition unit for acquiring exercise information of the vehicle;
  An estimated position calculation unit that calculates an estimated position of the vehicle in the future based on the movement information of the vehicle acquired by the movement information acquisition unit;
  When changing the lane from the own vehicle travel lane to the lane change target lane, the steering control unit is configured to determine whether the target position set by the target position setting unit and the estimated position calculated by the estimated position calculation unit. Based on the amount of deviation, steering control of the vehicle is performed.
The steering control device according to claim 1.   A lane change determining unit for determining whether to change the lane of the vehicle by steering control of the vehicle;
  The lane change determination unit determines to change the lane of the vehicle by steering control of the vehicle when the driver becomes unable to drive during traveling.
The steering control device according to claim 1 or 2.   The lane change determination unit is based on an operation of an emergency button installed in the vehicle or on the basis of an analysis result of a driver's face image captured by a camera installed in the vehicle cabin. Determine whether the driver is incapable of driving,
The steering control device according to claim 3.   The lane change determination unit determines to change the lane of the vehicle by steering control of the vehicle when the driver becomes unable to drive while traveling in the overtaking lane;
The steering control device according to claim 3 or 4.   Judging whether the vehicle is driving in an overtaking lane based on the distance to the shoulder or the map information,
The steering control device according to claim 5.

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