JP5359152B2 - Steering control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering control device capable of carrying out suitable steering control even if the offset of a vehicle is large. <P>SOLUTION: The steering control device sets a target position on a front side in a traveling direction of the vehicle, and carries out the steering control so as to make the vehicle travel on the target position. The steering control device calculates offset amount from a lane center position of the vehicle (S12), sets a target position at a position separating from the vehicle in proportion to the offset amount (S14), and carries out the steering control by calculating control torque according to the target position (S18, S20). Therefore, when the vehicle is returned to the lane center position by the steering control, it can be suppressed that the control torque is set to be large if the offset amount is large, and a sense of incongruity felt by a driver of the vehicle due to the steering control can be suppressed. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

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

Conventionally, as described in Japanese Patent Application Laid-Open No. 10-167100, for example, a target position is set on a traveling road ahead of the vehicle by a gaze distance, and the target position is traveled. Devices that perform steering control are known. This device is intended to perform appropriate steering control by varying the forward gaze distance according to the radius of curvature of the travel path.
JP-A-10-167100

  However, even in the above-described apparatus, it may be difficult to perform appropriate steering control. For example, when the vehicle position is shifted to the left and right and the offset amount with respect to the target position is large and when the offset amount is not large, if the steering control is executed with the same gaze distance set to the front, the offset amount is large. The steering amount of the steering wheel is increased by the steering control, and the driver feels uncomfortable.

  Accordingly, the present invention has been made to solve such problems, and an object thereof is to provide a steering control device that can perform appropriate steering control even when the offset of the vehicle is large.

That is, the steering control device according to the present invention is a steering control device that sets a target position in front of the traveling direction of the vehicle and performs steering control so that the vehicle travels in the target position, and the offset from the lane center position of the vehicle. Offset detecting means for detecting the amount, setting means for setting the target position at a position farther from the vehicle as the offset amount increases, and steering torque detecting means for detecting steering torque by a steering operation of the driver of the vehicle The setting means is further away from the vehicle when the steering torque is larger when the steering torque by the steering wheel operation is different from the direction of the control torque in the steering control and is equal to or larger than a predetermined value. The target position is set to a position .

According to the present invention, when the offset amount of the vehicle is returned to the lane center position by the steering control by setting the target position at a position farther from the vehicle as the offset amount of the vehicle is larger, the control torque is set to be larger when the offset amount is larger. It is possible to prevent the driver of the vehicle from feeling uncomfortable by the steering control. Further, when the steering torque by the steering wheel operation is different from the direction of the control torque in the steering control and is equal to or larger than a predetermined value set in advance, the target position is set at a position farther from the vehicle as the steering torque is larger. Thus, when the driver intentionally operates the steering wheel so as to leave the vehicle away from the center position of the lane, it is possible to prevent the driver from feeling uncomfortable.

  ADVANTAGE OF THE INVENTION According to this invention, even when the offset of a vehicle is large, it can suppress that a driver | operator feels uncomfortable by steering control, and appropriate steering assistance can be performed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 shows a schematic configuration diagram of a steering control device according to a first embodiment of the present invention.

  The steering control device 1 according to the present embodiment performs lane keeping (lane keeping) control that maintains the position of the vehicle at the center position of the lane that is the travel path, and performs steering assistance when the vehicle deviates from the lane. . For example, the steering control device 1 sets a target position in front of the traveling direction of the vehicle and executes steering control so that the vehicle travels at the target position.

  As shown in FIG. 1, the steering control device 1 is mounted on a vehicle to be steering controlled, and includes an imaging unit 2, a vehicle speed detection unit 3, a steering torque detection unit 4, an ECU (Electronic Control Unit) 5, and a steering actuator 6. Configured.

  The imaging unit 2 functions as an imaging unit that captures an image in front of the vehicle in the traveling direction, and a CCD camera, for example, is used. Image information captured by the imaging unit 2 is input to the ECU 5. The vehicle speed detection unit 3 functions as vehicle speed detection means for detecting the traveling speed of the vehicle, and for example, a vehicle speed sensor is used.

  The steering torque detector 4 functions as a steering torque detector that detects the steering torque of the steering wheel operation by the driver of the vehicle. For example, a torque sensor provided in the steering force transmission system is used.

  The ECU 5 performs control processing of the entire steering control device 1 and is mainly configured by a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), for example. The ECU 5 functions as a setting unit that sets a target position in steering control. The target position is set in front of the traveling direction of the vehicle, becomes a target position where the vehicle travels, and is referred to as a front gaze time or a front gaze distance. For example, the target position is set to a larger value as the vehicle speed increases, that is, a position farther away from the vehicle. Further, the target position is set to a position farther from the vehicle as the offset amount from the lane center position of the vehicle is larger.

  The ECU 5 also functions as an offset detection unit that detects an offset amount from the center position of the lane of the vehicle. For example, the ECU 5 receives an image signal from the imaging unit 2 and performs image processing on the captured image, thereby recognizing a white line on the road and detecting the vehicle offset based on the positional relationship with the white line.

  The ECU 5 also functions as a steering control unit that calculates a steering control torque and outputs a control signal corresponding to the steering control torque to the steering actuator 6. For example, the target yaw angular velocity γ is calculated by the following equation (1), the target lateral acceleration g is calculated by the equation (2), and the steering control torque corresponding to the target lateral acceleration g is calculated.

γ = (2 / V · T ² ) · D + (2 / T) · θ (1)

  g = V · γ (2)

  In equations (1) and (2), D is the offset amount of the vehicle, V is the vehicle speed, T is the forward gaze time (target position), and θ is the yaw angle of the vehicle. The offset amount D is detected, for example, by performing white line recognition and calculating the position of the vehicle with respect to the lane. A vehicle speed V based on the output signal of the vehicle speed detector 3 is used. The yaw angle θ is calculated by the angle formed by the white line and the traveling direction of the vehicle. The forward gaze time T is calculated according to the offset amount.

  The steering actuator 6 is an actuator that operates according to a control signal from the ECU 5 and applies control torque to the steering force transmission system of the vehicle. For example, a motor that applies control torque to the rack of the steering force transmission system is used. The steering actuator 6 may not be a rack assist type as long as it can provide a control torque to the steering force transmission system of the vehicle, and may be a column assist type or other type.

  2 and 3 show an example of a calculation map of the target position in the steering control device according to the present embodiment.

  As shown in FIG. 2, in the steering control device 1, the target position (front gaze time or front gaze distance) in the steering control is set to a larger value as the vehicle offset amount increases, and is calculated so as to be farther from the vehicle. Is set. Note that the target position in the steering control is not limited to the offset-target position characteristic as shown in FIG. 2 as long as the offset amount of the vehicle is set so as to be farther from the vehicle. For example, the target position characteristic may be set so as to include a curve, or may be changed stepwise according to the offset amount.

  Further, as shown in FIG. 3, in the steering control device 1, when the steering torque by the steering operation of the driver of the vehicle is different from the direction of the control torque in the steering control and is equal to or larger than a predetermined value, It is preferable that the target position is set to a larger value as the steering torque is larger, and is calculated and set so as to be far away from the vehicle. In this case, the target position in the steering control is not limited to the characteristic of the steering torque-target position as shown in FIG. 3 as long as the target position is set to be farther from the vehicle as the steering torque is larger. For example, the target position characteristic may be set so as to include a curve, or may be changed stepwise according to the steering torque.

  FIG. 4 is a flowchart showing the operation of the steering control device according to the present embodiment.

  A series of control processes in FIG. 4 are repeatedly executed by the ECU 5 at a predetermined cycle, for example. First, as shown in S10 of FIG. 4, a sensor reading process is performed. The sensor reading process is a process of reading the captured image signals and detection signals of the imaging unit 2, the vehicle speed detection unit 3, and the steering torque detection unit 4.

  And it transfers to S12 and an offset calculation process is performed. The offset calculation process is a process for calculating an offset amount from the lane center position of the vehicle. For example, the offset amount is calculated by performing image processing on the captured image to recognize a white line and calculating the position of the vehicle with respect to the lane.

  Then, the process proceeds to S14, and target position calculation processing is performed. The target position calculation process is a process for calculating a target position in the steering control. The target position is set in front of the vehicle, and is set at a position farther from the vehicle as the offset amount is larger. For example, the target position is first calculated according to the vehicle speed, and calculated and set according to the offset amount. Furthermore, it is preferable to vary the target position according to the curvature of the vehicle travel path. In this case, it is preferable that the target position is set closer as the curvature of the travel path increases. By setting in this way, steering control can be performed while suppressing the uncomfortable feeling that occurs to the driver.

  Then, the process proceeds to S16, and a target lateral acceleration calculation process is performed. The target lateral acceleration calculation process is a process for calculating a target lateral acceleration for the vehicle to travel the target position in the current traveling state of the vehicle. This target lateral acceleration calculation processing may be performed using, for example, the above-described equations (1) and (2).

  And it transfers to S18 and a control torque calculation process is performed. The control torque calculation process is a process of calculating a control torque (assist torque) given to the steering force transmission system as steering control. The control torque is calculated according to the target lateral acceleration. Then, the process proceeds to S20, where a control signal corresponding to the control torque is output to the steering actuator 6, and the steering control process is performed. When the steering control process in S20 is finished, a series of control processes are finished.

  As described above, according to the steering control device 1 according to the present embodiment, the target position p is set at a position farther from the vehicle M as the offset amount D of the vehicle M is larger, as shown in FIG. For this reason, compared with the case where the target position is set at the close position p1, the control torque for returning the vehicle M to the lane center position O by the steering control is reduced, and the vehicle M is gradually returned to the lane center position O. It will be. For this reason, it can suppress that the driver | operator of a vehicle feels uncomfortable by steering control.

  In the steering control device 1 according to the present embodiment, the steering torque is large when the steering torque by the driver's steering operation is different from the direction of the control torque by the steering control and is equal to or larger than a predetermined value. The target position is set at a position far away from the vehicle. Thereby, when the driver intentionally operates the steering wheel so as to leave the vehicle away from the center position of the lane, it is possible to prevent the driver from feeling uncomfortable.

  The embodiment described above is an example of the steering control device according to the present invention, and the steering control device according to the present invention is not limited to the one described in the present embodiment. The steering control device according to the present invention may be a modification of the steering control device according to the embodiment or application to other devices without changing the gist described in each claim. For example, in the above-described embodiment, the case where the target position is set in front of the vehicle and applied to the steering control when the vehicle moves forward is described, but the present invention may be applied to the steering control when the vehicle moves backward. In this case, the steering control may be performed by setting the target position in the forward direction of the vehicle, that is, in the rear of the vehicle.

1 is a schematic configuration diagram of a steering control device according to an embodiment of the present invention. It is explanatory drawing of the target position calculation map of the steering control apparatus of FIG. It is explanatory drawing of the target position calculation map of the steering control apparatus of FIG. It is a flowchart which shows operation | movement of the steering control apparatus of FIG. It is operation | movement explanatory drawing of the steering control apparatus of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Steering control apparatus, 2 ... Imaging part, 3 ... Vehicle speed detection part, 4 ... ECU, 5 ... Steering actuator.

Claims (1)

In a steering control device that performs steering control so that a target position is set in front of the traveling direction of the vehicle and the vehicle travels through the target position,
Offset detecting means for detecting an offset amount from a lane center position of the vehicle;
Setting means for setting the target position at a position farther from the vehicle as the offset amount is larger;
Steering torque detection means for detecting steering torque by a steering operation of a driver of the vehicle;
Equipped with a,
When the steering torque by the steering operation is different from the direction of the control torque in the steering control and is equal to or greater than a predetermined value set in advance, the setting means increases the steering torque to a position farther from the vehicle. A steering control device characterized by setting a position .

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