JP4636331B2 - Vehicle steering system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent contact of a vehicle with its surrounding obstacles etc. due to steering failure of a driver, at the time of switching to manual operation by the driver after an automatic parking mode is interrupted in the middle and the vehicle is stopped. <P>SOLUTION: After interruption of automatic steering control, when a steering wheel 1 is manually operated and a steered wheel 4 is steered, information in a two-dimensional coordinate system memory 25 is read out. When the wheel 4 is steered to a direction in which the vehicle can interfere with an obstacle around the vehicle, guidance torque to suppress the steering operation is generated by operating a reaction force actuator 19. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a vehicle steering apparatus for moving a vehicle in a desired direction, and more particularly to a vehicle steering apparatus capable of performing automatic steering in order to park the vehicle at a desired parking position.

Patent Document 1 discloses a technique for interrupting automatic parking control at a more appropriate stage based on the relationship between the detected vehicle speed and the accelerator opening when the vehicle is automatically guided to the target parking position by automatic parking control. It is disclosed.
In the technique disclosed in Patent Document 1, it is determined whether parking assistance control is interrupted based on the relationship between the detected value of the vehicle speed and the detected value of the accelerator opening, and the vehicle speed actually increases from the depression operation of the accelerator pedal. In consideration of a delay in time until the vehicle speed is reached, automatic parking control is interrupted before the vehicle speed reaches a high value at which parking support control should be interrupted.

Patent Document 2 discloses a technique of correcting a steering pattern in order to avoid a contact with an obstacle in a vehicle automatic steering device. Further, Patent Document 3 discloses a technique for setting a steering angle to a smaller value as the vehicle speed increases in an automatic vehicle steering apparatus.
JP 2004-284530 A Japanese Patent No. 3130970 Japanese Patent No. 3031758

  The technique described in Patent Document 1 is a technique for appropriately interrupting automatic parking control in the middle. However, during automatic parking control, the driver leaves the steering operation up to that time to the vehicle side. When the vehicle is interrupted, the relationship between the vehicle and other vehicles and obstacles around it may not be fully understood. Become. For this reason, when the other vehicle and the obstacle which the driver does not grasp exist around the own vehicle, there is a possibility of contacting with the other vehicle or the obstacle.

  In addition to automatic parking control, when the vehicle is being automatically steered, when the automatic steering is interrupted and switched to manual operation by the driver, the driver must Because you are not paying enough attention to the presence of other vehicles and obstacles, your vehicle may come into contact with other vehicles or obstacles immediately after switching to manual steering. Is expensive.

The present invention has been made based on such a background. When the driver manually operates the vehicle steering device after the automatic steering of the vehicle steering device is interrupted, the vehicle is obstructed by the surrounding obstacles. The main object of the present invention is to provide a vehicle steering system that is devised so as not to come into contact with the vehicle.
The present invention also prevents the driver from steering the vehicle in a direction in contact with surrounding obstacles when the vehicle steering apparatus switches from automatic steering to manual operation. Another object of the present invention is to provide a vehicle steering device that prevents erroneous steering due to accidental mistakes.

According to the first aspect of the present invention, there is provided an operating member (1) operated by a driver for steering a vehicle and steering for turning a steering wheel (4) in response to the operation of the operating member. Two-dimensional coordinates of information about the mechanism (2, 5), automatic driving mode setting means (21) for setting automatic driving control, and surrounding obstacles around the host vehicle during automatic driving control A two-dimensional coordinate system storage means (25) for storing while being updated in the system, and an automatic steering control means (20) for controlling the steering mechanism (2, 5) so that the vehicle performs a predetermined travel in the automatic travel mode. 22) and a discriminating means for discriminating that the automatic steering control is released while the automatic steering control by the automatic steering control means is being performed, and after the discriminating means discriminates the release of the automatic steering control, The operation member (1) When operated and the steering wheel (4) is steered by the steering mechanism (2, 5), the information of the two-dimensional coordinate system storage means (25) is read, and the vehicle interferes with obstacles around the vehicle. Steering suppression means (20, 23, 19) for causing the operating member to generate a guidance torque for suppressing the steering operation when the wheel is steered in a direction to obtain the vehicle. It is a steering device.
According to a second aspect of the present invention, in the vehicle steering apparatus according to the first aspect, the determination unit determines whether the automatic steering control is canceled by detecting a brake operation or a steering operation of the driver. is there.

Alphanumeric characters in parentheses indicate corresponding components in the embodiments described later. The same applies hereinafter.
In the above configuration, when the driver operates the operation member (1), the steering wheel (4) is steered by the steering mechanism (2, 5), and the vehicle can be steered in a desired direction.
Moreover, it can be in the state in which automatic driving | running | working control is performed because a driver | operator operates automatic driving mode setting means (21). In the automatic traveling control (automatic traveling mode), the steering wheel (4) is moved by the automatic steering control means (20, 22) so that the vehicle performs predetermined traveling (for example, automatic parking at a predetermined parking position). Steered.

During the automatic travel control, the two-dimensional coordinate system storage means (25) stores information about obstacles around the host vehicle while being updated in the two-dimensional coordinate system.
When the automatic travel mode is interrupted, information about obstacles around the host vehicle is read from the two-dimensional coordinate system storage means (25). Based on the read information, the vehicle When a wheel is steered by a manual operation in a direction that can interfere with obstacles and the like around the vehicle, guidance torque for suppressing the steer operation is generated on the operation member (1). Therefore, based on this guidance torque, the driver realizes that the operating member (1) should not be operated in that direction, and the vehicle is not obstructed by the driver after the automatic steering control is interrupted due to inadvertent driving or the like. Can be prevented from contacting.

  An alarm may be issued instead of the guidance torque or together with the guidance torque.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an illustrative view for explaining the configuration of a vehicle steering apparatus according to an embodiment of the present invention, and shows the configuration of a so-called steer-by-wire system. The vehicle steering apparatus includes a steering wheel 1 as an operation member that a driver operates for steering, a steering actuator 2 that is driven in response to a rotational operation of the steering wheel 1, and a steering actuator. And a steering gear 3 that transmits the driving force 2 to, for example, the front left and right wheels 4 as steering wheels. There is no mechanical connection between the steering wheel 1 and the steering mechanism 5 including the steering actuator 2 so that the operating torque applied to the steering wheel 1 is mechanically transmitted to the steering mechanism 5. The wheel 4 is steered by driving and controlling the steering actuator 2 in accordance with the operation amount (operation angle or operation torque) of the wheel 1.

  The steering actuator 2 can be constituted by an electric motor such as a known brushless motor. The steering gear 3 has a motion conversion mechanism that converts the rotational motion of the output shaft of the steering actuator 2 into linear motion of the steering rod 7 (linear motion in the vehicle left-right direction). The movement of the steering rod 7 is transmitted to the wheel 4 via the tie rod 8 and the knuckle arm 9, and the toe angle (steering angle) of the wheel 4 changes. As the steering gear 3, a known one can be used, and the configuration is not limited as long as the movement of the steering actuator 2 can be transmitted to the wheels 4 so that the steering angle changes. In the state where the steering actuator 2 is not driven, the wheel alignment is set so that the wheel 4 can return to the straight steering position by the self-aligning torque.

  The steering wheel 1 is connected to a rotating shaft 10 that is rotatably supported on the vehicle body side. The rotary shaft 10 is provided with a reaction force actuator 19 that generates a reaction force torque acting on the steering wheel 1. The reaction force actuator 19 can be constituted by an electric motor such as a brushless motor having an output shaft integrated with the rotary shaft 10.

  An elastic member 30 is provided between the vehicle body and the rotating shaft 10 to provide elasticity in a direction to return the steering wheel 1 to the straight steering position. The elastic member 30 can be constituted by, for example, a spring that imparts elasticity to the rotary shaft 10. When the reaction force actuator 19 does not apply torque to the rotary shaft 10, the steering wheel 1 returns to the straight steering position by the elasticity of the elastic member 30.

  In order to detect the operation angle (rotation angle) of the steering wheel 1, an angle sensor 11 that detects the rotation angle δh of the rotary shaft 10 is provided. In addition, a torque sensor 12 that detects torque transmitted by the rotary shaft 10 is provided in order to detect an operation torque Th that the driver of the vehicle acts on the steering wheel 1. Furthermore, the steering angle sensor 13 for detecting the steering angle (steering angle of the steering mechanism 5) δ of the vehicle is constituted by a potentiometer that detects the operation amount of the steering rod 7 corresponding to the steering angle. A speed sensor 14 for detecting the vehicle speed V, a lateral acceleration sensor 15 for detecting the lateral acceleration Gy of the vehicle, and a yaw rate sensor 16 for detecting the yaw rate γ of the vehicle are provided.

Further, a rear monitor camera 17 for imaging the state of the rear of the vehicle, and a detection signal (for example, infrared rays, ultrasonic waves, etc.) toward the side of the vehicle and diagonally rearward, etc. An obstacle sensor 18 for detecting the obstacle is provided.
These angle sensor 11, torque sensor 12, rudder angle sensor 13, speed sensor 14, lateral acceleration sensor 15 and yaw rate sensor 16 are respectively connected to a control device 20 constituted by a computer. The control device 20 controls the steering actuator 2 and the reaction force actuator 19 via the drive circuits 22 and 23. The control device 20 is provided with a two-dimensional coordinate system memory (two-dimensional coordinate system storage means) 25 used in an automatic parking mode described later.

Further, an automatic travel mode setting switch 21 is provided at a position where the driver of the vehicle can operate.
When the automatic travel mode setting switch 21 is turned on, the signal is given to the control device 20, and the vehicle steering device is automatically controlled by the control device 20. When the automatic travel mode is the automatic parking mode, detection outputs of the rear monitor camera 17 and the obstacle sensor 18 are utilized.

FIG. 2 is an illustrative view showing a control method when the vehicle is moved to a predetermined parking position in the automatic parking mode as an example of the automatic traveling mode. The own vehicle information and the surrounding information appearing in this illustration are grasped as two-dimensional information, and updated and stored as needed in the two-dimensional coordinate system memory 25 as will be described later.
Assume that the host vehicle A is moved back from the current position P1 to the parking position P2 as the target position, and is parked in parallel between the side parked vehicle B and the rear parked vehicle C. At the current position P1, the driver of the host vehicle A presses the automatic travel mode setting switch 21 (see FIG. 1) to set the vehicle steering device of the host vehicle A to the automatic parking mode. In response to this, the rear monitor camera 17 is actuated, and a landscape behind the host vehicle A is imaged, and the state is displayed on a monitor screen (not shown) in the host vehicle A. The driver designates the parking position (target position) P2 on the monitor screen while checking the monitor screen.

The designation of the parking position (target position) P2 is registered in advance, for example, with the current position P1 of the host vehicle A received by the GPS receiver instead of the way in which the driver confirms the monitor screen in this way. It is also possible to automatically set based on the difference from the position coordinates of the parked parking position P2.
When the parking position P2 is designated, the control device 20 performs the parallel parking to the parking position P2 without moving the course from the current position P1 to the parking position P2, that is, the own vehicle A does not contact an obstacle or the like. The course to be moved back is obtained as the target locus 40.

In the host vehicle A, first, at the current position P1, the image data captured by the rear monitor camera 17, the presence or absence of surrounding obstacles detected by the obstacle sensor 18 (see FIG. 1), and the obstacles. Ambient information such as the distance is stored in the memory 25 together with the information of the host vehicle A.
Here, the information of the host vehicle A includes, for example, the position and orientation of the host vehicle A, the specifications of the host vehicle A (wheelbase length, tread base length, etc.), the current steering angle of the steering wheel 1, and the current wheel 4 Related to the position information and travel of the host vehicle A, such as the turning angle of the vehicle, the vehicle speed V detected by the speed sensor 14, the lateral acceleration Gy detected by the lateral acceleration sensor 15, and the yaw rate γ detected by the yaw rate sensor 16. Various types of information.

The surrounding information of the host vehicle A includes the presence of the side parked vehicle B, the position information of the vehicle B, particularly the distance information to the right side portion 50 and the right rear corner portion 51 of the vehicle B, the left edge 52 of the road. Distance information, information that the rear parked vehicle C exists, distance information to the vehicle C, particularly distance information to the front end portion 53 of the vehicle C, and the like.
These pieces of information are stored in the two-dimensional coordinate system memory 25 as coordinate data in a two-dimensional coordinate system represented by an orthogonal X axis and Y axis passing through the origin 0, for example, with the central portion of the host vehicle A as the origin 0.

In this embodiment, the two-dimensional coordinate system is represented by an XY coordinate, but may be represented by an Xθ coordinate represented by a length and an angle.
The stored two-dimensional coordinate system data indicates that the positional relationship between the own vehicle A and the surrounding information changes as the own vehicle A moves so as to follow the calculated target locus 40. The vehicle information and the surrounding information are updated and stored as the vehicle A moves.

The two-dimensional coordinate system memory 25 for storing such information of the own vehicle A and surrounding information is provided, and the stored own vehicle information and surrounding information are updated as the own vehicle A moves as needed. Updating and storing is one of the features of this embodiment.
By the way, as shown schematically in FIG. 2, when the own vehicle A is automatically parked so as to follow the target locus 40, it is caused by some reason, for example, the driver intervening in steering. It is assumed that the direction of the host vehicle A changes greatly, the automatic parking control is interrupted, and the host vehicle A is stopped in the state shown in FIG.

  In the state shown in FIG. 3, when the automatic parking control of the host vehicle A is interrupted and released, the driver is not involved in the steering control of the host vehicle A except when, for example, steering intervention is performed. In the state shown in FIG. 3, the vehicle A may not fully understand the positional relationship with the side parked vehicle B or the road left edge 52. Further, the steering angle of the steering wheel 1 may not be sufficiently grasped.

In such a state, when the driver of the own vehicle A steers the steering wheel 1 counterclockwise and starts to turn the own vehicle A to the left, the own vehicle A becomes the right rear corner of the side parked vehicle B. There is a possibility of contact with the portion 51.
In this embodiment, in such a case, in order to avoid the own vehicle A coming into contact with the right rear corner 51 of the side parked vehicle B, guidance is given to the steering wheel 1 that the driver is to operate. A vehicle in a case where torque (reaction torque against counterclockwise rotation for prohibiting counterclockwise rotation) is generated, and the driver inadvertently starts manual driving without fully grasping the current situation of the host vehicle A To prevent contact.

In the memory 25, when the host vehicle A reaches the position shown in FIG. 3, the information of the host vehicle A and the surrounding information are updated and stored. That is, position information of the host vehicle A, information on the steering angle of the steering wheel 1, steering angle information on the steering wheel, distance information to the right rear corner 51 of the side parked vehicle B, and the like are stored.
Therefore, the control device 20 can generate an appropriate guidance torque based on the own vehicle information and the surrounding information stored in the memory 25 to call the driver's attention.

FIG. 4 is a flowchart showing the contents of the control process of the vehicle steering device provided in host vehicle A, which is executed by control device 20 shown in FIG.
Next, according to the flow of FIG. 4, the control procedure in this embodiment will be described with reference to FIGS.
When the control is started and the automatic travel mode setting switch 21 is pressed and the automatic parking mode is set (YES in step S1), the target locus is calculated by the control device 20 (step S2).

As described with reference to FIG. 2, the target trajectory is a course in which the host vehicle A can move from the current position P1 to the target parking position P2 in the back without touching an obstacle or the like. This target locus is obtained (step S2).
Then, the steering mechanism 5 including the steering actuator 2 is automatically steered by the control device 20 via the drive circuit 22, and automatic parking control is started (step S3).

While the host vehicle A is under automatic parking control, the host vehicle information and surrounding information are always detected, and the detected host vehicle information and surrounding information are updated and stored in the memory 25 as needed (step S4).
The control device 20 determines whether or not the automatic parking mode is canceled while performing automatic parking control (step S5). The automatic parking mode can be canceled by, for example, turning off the automatic travel mode setting switch 21 or other known methods. As a known method, for example, as described in Japanese Patent Application Laid-Open No. 10-114272, when the driver removes his foot from the brake pedal, or when the driver performs steering intervention by operating the steering wheel 1 or the like. It can be illustrated.

When it is determined that the automatic parking mode is to be released (YES in step S5), the control device 20 reads the vehicle information and surrounding information stored in the two-dimensional coordinate system memory 25, and based on the information, The vehicle A calculates whether or not there is a possibility of contact with surrounding objects (obstacles, vehicles, etc.) depending on the manner of subsequent steering (step S6).
This calculation is updated and stored in the memory 25, just before the automatic parking mode is canceled, the positional relationship between the host vehicle A and the side parked vehicle B, the direction of the host vehicle A, the specifications of the host vehicle A (wheel Base length, tread base length, turning radius, etc.), current steering angle of the own vehicle A, current turning angle of the steering wheel 4, etc., the current position of the own vehicle A and the side vehicle B, for example From the relationship, it is calculated in what direction the vehicle speed V of the host vehicle travels and whether or not it contacts the right rear corner 51 of the side parked vehicle B.

  As a result, when it is determined that the host vehicle A may come into contact with the right rear corner 51 of the side parked vehicle B (YES in step S7), the driver subsequently performs manual driving of the host vehicle A. When started (step S8), a guidance torque for prohibiting steering in the contact direction is generated (step S9). Generation of the guidance torque can be realized by controlling the reaction force actuator 19 via the drive circuit 23.

  In the automatic parking control, the steering mechanism 5 including the steering actuator 2 is usually automatically operated, and the host vehicle A travels in a predetermined direction. When the automatic parking control is interrupted halfway, the steering wheel 4 is stopped in a steered state, and the steering wheel 1 may be steered depending on the control method. It may not have been done. During automatic parking control, the driver usually leaves his hand from the steering wheel 1 and leaves the vehicle to automatic control by the control device 20. For this reason, attention is not paid to the surroundings of the own vehicle A, and what kind of obstacles are present around the own vehicle A may not be taken care of.

Under these circumstances, when automatic parking control is interrupted and manual steering is performed by the driver, the driver may not be able to fully grasp the current situation of the vehicle, such as an inadvertent mistake Due to this, there is a possibility of contact with obstacles around the host vehicle and other vehicles.
According to this embodiment, in a situation where such a contact can occur, in order to prohibit steering in the direction in which the contact occurs, a steering prohibiting guidance torque in the contact direction is generated, and the vehicle is in a contact accident. This prevents inconveniences such as the occurrence of problems.

  In the above description, the automatic parking mode has been described as an example of the automatic traveling mode. However, the present invention is not limited to the automatic parking mode, and is widely applied to the case where the host vehicle A is controlled in the automatic travel mode, and when the control is interrupted, the driver switches to manual steering. It is possible to provide a vehicle steering apparatus that allows the driver to start driving more safely at the time of switching from automatic steering to manual steering.

  Further, in the above-described embodiment, the example in which the present invention is applied to the steer-by-wire system has been described. However, the present invention is directed to a vehicle steering system provided with a steering actuator that applies a steering force to a steering mechanism of the vehicle. It can be widely applied to the device. Such a vehicle steering apparatus includes an electric power steering apparatus, a hydraulic power steering apparatus, and the like.

  In addition, the present invention is not limited to the above described items, and various modifications can be made within the scope of the claims.

It is an illustration figure for demonstrating the structure of the steering apparatus for vehicles which concerns on one Embodiment of this invention. It is an illustration figure which shows the method of control when moving a vehicle to a predetermined parking position in automatic parking mode. It is an illustration figure assuming the case where automatic parking control is interrupted on the way, the own vehicle A stops, and automatic parking control is cancelled | released. 3 is a flowchart showing the contents of a control process of a vehicle steering device provided in own vehicle A, which is executed by control device 20.

Explanation of symbols

  1: steering wheel, 2: steering actuator, 4: steering wheel, 20: control device, 21: automatic travel mode setting switch, 25: two-dimensional coordinate system memory, 40: target locus, A: own vehicle

Claims (2)

An operation member operated by the driver for steering the vehicle;
A steering mechanism that steers steering wheels in response to the operation member being operated;
Automatic driving mode setting means for making a state in which automatic driving control is performed;
Two-dimensional coordinate system storage means for storing information on obstacles around the host vehicle during automatic traveling control while updating the information in the two-dimensional coordinate system;
Automatic steering control means for controlling the steering mechanism so that the vehicle performs predetermined traveling in the automatic traveling mode;
A discriminating means for discriminating that the automatic steering control is released while the automatic steering control by the automatic steering control means is being performed;
After the discriminating means discriminates the release of the automatic steering control, when the operating member is operated and the steering wheel is steered by the steering mechanism, the information in the two-dimensional coordinate system storage means is read and the vehicle is When the wheels are steered in a direction that can interfere with other obstacles, steering suppression means for generating a guidance torque for suppressing the steering operation in the operation member,
A vehicle steering apparatus comprising: The vehicle steering apparatus according to claim 1, wherein the determination unit determines a release of automatic steering control by detecting a brake operation or a steering operation of a driver.

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