JP2008230388A - Steering control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To construct a highly reliable steering control device for a vehicle by informing a driver of the actual condition of a steering wheel and the road surface during driving of the vehicle. <P>SOLUTION: The steering control device for the vehicle is provided with: a control means equipped with a steering amount calculating means for determining the steering amount of the steering wheel based on a steering angle detected by a road surface condition detecting means for detecting the road surface condition based on vehicle information, and a steering angle detecting means; and a display device including a first display means for displaying at least the steering direction and the steering amount of the steering wheel, and a second display means for displaying the road surface condition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle steering control device, and more particularly to a vehicle steering control device for notifying a driver of vehicle information.

In a vehicle steering system, vehicle information such as an operation angle (steering wheel operation angle), a wheel steering angle, a road surface condition (a rut, a step), which is an angle at which a steering wheel is operated, is determined by a driver's sense. In this way, the vehicle information can be determined by the driver's feeling because the steering system has a mechanical link structure.
In addition, some vehicle steering systems employ a so-called steer-by-wire system (steer-by-wire system) that electrically drives a steered wheel with respect to a manually operated steering wheel.
The steering system employing this steer-by-wire system has a structure in which the steering wheel and the steering gear box are mechanically separated, and the vehicle information as described above can be determined only by the driver's sense as in the past. Is impossible.
Further, in the steering system employing the steer-by-wire system, the ratio of the steering wheel operation angle to the wheel steering angle can be varied by eliminating the mechanical connection. For this reason, the steering wheel operation angle and the wheel steering angle are not necessarily in a 1: 1 relationship, and the current gear ratio may be misunderstood only by judgment based on the driver's sense. It was necessary to notify the driver of the steering wheel operation angle and the wheel steering angle in some form.

2. Description of the Related Art Conventionally, there is a steering apparatus that employs a steer-by-wire system that eliminates the uncomfortable feeling during reverse turning by matching the steering wheel operation direction with the turning direction of the vehicle even during reverse.
Some control devices for electric power steering devices limit assist with a natural steering feeling in the vicinity of the rack end (maximum steering angle).
JP 2004-322978 A JP 2006-248252 A

  By the way, conventionally, in the steering device adopting the steer-by-wire system in the above-mentioned Patent Document 1, there is a disadvantage that only the wheel steering angle can be notified only when the vehicle is limited to the reverse travel.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle steering control for notifying the driver of the actual state of the steered wheels and the road surface condition while driving the vehicle, and constructing a highly reliable vehicle control system. To provide an apparatus.

  The present invention provides an operation angle detection means for detecting an operation angle that is an angle at which the steering wheel is operated, a steering angle detection means for detecting a steering angle of a steered wheel, and detects a road surface condition based on vehicle information. In a vehicle steering control apparatus provided with a control means provided with a steering amount calculation means for determining a steering amount of the steered wheel based on a road surface condition detection means and a steering angle detected by the steering angle detection means, A display device having a first display means for displaying a steering direction and a steering amount of the steered wheels and a second display means for displaying a road surface condition is provided.

  The vehicle steering control device according to the present invention includes a display device having first display means for displaying at least a steering direction and a steering amount of a steered wheel and second display means for displaying a road surface condition. In addition, it is possible to construct a highly reliable vehicle control system by notifying the driver of the state of the steered wheels and the road surface condition.

The object of the present invention is to notify the driver of the actual state of the steered wheel and the road surface condition while driving the vehicle, and to construct a highly reliable vehicle control system. This is realized by a display device having first display means for displaying the direction and the steering amount and second display means for displaying the road surface condition.
Hereinafter, embodiments of the present invention will be described in detail and specifically with reference to the drawings.

  1 to 8 show an embodiment of the present invention. In FIG. 3, 1 is a vehicle and 2 is a steering system. The steering system 2 employs a so-called steer-by-wire system (steer-by-wire system), and includes an operation mechanism 3 and a steering mechanism 4 that are not mechanically connected, and the steering mechanism 4 is electrically driven to generate a gear ratio. Is freely variable.

As shown in FIG. 3, the operation mechanism 3 is attached to the steering wheel 6 attached to the upper end portion of the steering shaft 5, the steering column 7 attached to the shaft portion of the steering shaft 5, and the lower end portion of the steering shaft 5. A reaction force generation mechanism 8 and a rotation stopper mechanism 9 are provided. The reaction force generation mechanism 8 applies a reaction force to the steering wheel 6. The rotation stopper mechanism 9 has a rack end structure, and limits the rotation speed of the steering wheel 6 by the rack end angle (maximum steering angle).
In addition, an operation angle sensor 10 that is an operation angle detection unit that detects an operation angle (handle operation angle) that is an angle at which the steering wheel 6 is operated at the upper end of the steering column 7 is configured at the shaft portion of the steering shaft 5. The first operating angle sensor 10A, the torque sensor 11 that detects the rotational torque of the steering wheel 6 and the operating angle (handle) that is the operating angle of the steering wheel 6 between the lower end of the steering column 7 and the reaction force generating mechanism 8 A second operation angle sensor 10B constituting the operation angle sensor 10 which is an operation angle detection means for detecting an operation angle) is attached.
A steering motor 12 connected to a built-in gear is attached to the steering column 7. The steering motor 12 outputs a reaction force against the rotation of the steering wheel 6 or an assist force (power steering force) for assisting the rotation.

The steering mechanism 4 is connected to the left front wheel 13L and the right front wheel 13R as steering wheels, the left tie rod 14L and the right tie rod 14R for driving the left front wheel 13L and the right front wheel 13R, and the left tie rod 14L and the right tie rod 14R. A steering gear box 15 incorporating a rack shaft, a pinion shaft 16 connected to the rack shaft of the steering gear box 15, and a steering gear box 17 attached to the pinion shaft 16 and incorporating a gear are provided.
The pinion shaft 16 includes two steering angle sensors 18 that are steering angle detection means for detecting the rotation angle of the pinion shaft 16 as the steering angle of the steering wheel (wheel steering angle) above the steering gear box 17. A first steering angle sensor 18A and a second steering angle sensor 18B are attached.
Two first steering motors 19 </ b> A and a second steering motor 19 </ b> B, which are steering motors 19, are attached to the steering gear box 17 so as to be connected to a built-in gear. The first steering motor 19A and the second steering motor 19B perform steering control of the left front wheel 13L and the right front wheel 13R.

The steering system 2 is driven by the vehicle steering control device 20.
As shown in FIG. 3, the vehicle steering control device 20 includes control means 21. The control means 21 is provided with an operation control device 22, a first steering control device 23, and a second steering control device 24. Also, the reaction force generation mechanism 8, the first operation angle sensor 10A, and the second control device 21 are provided. The operation angle sensor 10B, the torque sensor 11, the steering motor 12, the first steering angle sensor 18A, the second steering angle sensor 18B, the first steering motor 19A, and the second steering motor 19B communicate with each other. The operation control device 22 directly communicates with the steering motor 12 and commands the reaction force and assist force of the steering motor 12. The first steering control device 23 communicates directly with the first steering motor 19A and drives the first steering motor 19A. The second steering control device 24 directly communicates with the second steering motor 19B and drives the second steering motor 19B.

Further, as shown in FIG. 2, the control means 21 of the vehicle steering control device 20 includes a steering motor 19 on the input side as the vehicle information detection means 25 in addition to the operation angle sensor 10 and the steering angle sensor 18. A current sensor 26 for detecting the current of the vehicle 1, a yaw rate sensor 27 for detecting the rotational angular velocity around the vertical axis of the vehicle 1, a lateral G sensor 28 for detecting a right-angle component with respect to the traveling direction of the vehicle 1, and a velocity of the vehicle 1 The vehicle speed sensor 29 is connected to a forward / backward sensor 30 for detecting the forward / backward movement state of the vehicle 1, and the reaction force generating mechanism 8, the steering motor 19, and the instrument panel are installed on the output side. A display device 31 is connected.
As shown in FIG. 2, the control means 21 includes a road surface condition detection means 32 that detects a road surface condition based on vehicle information, and a steering amount of a steered wheel based on a steering angle detected by the steering angle sensor 18. Steering amount calculation means 33 for determining vehicle information, vehicle information estimation calculation means 34 for estimating vehicle information, road surface condition data calling means 35 for calling road surface condition data, image data conversion means 36 for converting image data, and operation angle sensor And a maximum steering angle determining means 37 for determining whether or not the steering angle estimated from the detected value from 10 has reached the rack end angle (maximum steering angle: steering limit point).

The control means 21 detects the road surface condition (for example, no load, asphalt, rough road) by the road surface condition detection means 32 based on vehicle information from the current sensor 26, the yaw rate sensor 27, the lateral G sensor 28, the vehicle speed sensor 29, and the forward / reverse sensor 30 , Wet, etc.).
As shown in FIG. 6, the estimation of the road surface condition is determined by the road surface state detection means 32 from the detection values of the various sensors described above based on the various road surface condition data created by measurement.
In addition, by reflecting these vehicle information estimation results in the reaction force control of the steering wheel 6 and the steering control of the left front wheel 13L and the right front wheel 13R, the reliability and running performance of the steering system 2 adopting the steer-by-wire system are improved. It can also be improved.

As shown in FIGS. 4 and 5, the display device 31 displays vehicle information to a driver who is a user, and displays at least the steering direction and the steering amount of the left front wheel 13L and the right front wheel 13R which are steering wheels. It has the 1st display means 38 which displays, and the 2nd display means 39 which displays a road surface condition.
The display device 31 is a device that can visually recognize the steering direction, the steering amount, and the change in the road surface condition of the left front wheel 13L and the right front wheel 13R that are steering wheels. Further, when the steering angle (wheel steering angle) estimated from the detection value from the operation angle sensor 10 is the maximum steering angle (rack end angle), the display device 31 determines that the estimated steering angle is the maximum value. Displays that the steering angle has been reached.
A display device 31 shown in FIG. 4 is an example for displaying a steering image of the vehicle 1 on which the steering system 2 adopting the steer-by-wire system is mounted.
The display device 31 shown in FIG. 5 is an example for grasping the road surface condition.
The display device 31 shown in FIG. 5 is proposed based on the concept described in FIGS. 7 and 8.
That is, in the conventional steering control device having a mechanical link structure, road surface conditions such as rutting and steps are transmitted almost directly to the driver. However, in the case of the steering system 2 that adopts the steer-by-wire method, there is no mechanical link structure that transmits the road surface condition, so it has been necessary to consider from the viewpoint of reaction force design and steering design. Therefore, the idea of “Visibility” (degree of visibility), which is an index related to vision, is applied to grasping the road surface condition, and this idea is handled as the concept of “Sensitivity” (degree of feeling).
FIG. 7 is an example of visual recognition support of the vehicle ahead by “Visibility” (degree of visibility).
FIG. 8 shows an example of visual recognition support on the road surface based on “Sensitivity” (degree of feeling).
As a recognition support technology in the steering system 2 adopting the steer-by-wire method, the display device 31 of FIG. 4 and the display device 31 of FIG. 5 are integrated by a single display device to display vehicle information. Certainty and operability can also be improved.

Next, the vehicle steering control in this embodiment will be described based on the flowchart of FIG.
As shown in FIG. 1, when the program of the control means 21 is started (step A01), first, vehicle information is acquired (step A02), the current wheel steering angle is estimated (step A03), and the estimated wheel The steering angle is converted into image data (step A04), the display image of the wheel steering angle is updated (step A05), the steering wheel operation angle is estimated (step A06), and the display device 31 visually displays it in real time. To the driver.
Thereafter, it is determined from the design information of the vehicle 1 and the estimated wheel steering angle whether or not the wheel steering angle has reached the maximum steering angle (rack end angle) (step A07).
If this step A07 is YES, the rack end notification information is converted into image data (step A08), the rack end display screen is updated (step A09), and the presence of this rack end is shown in FIG. Visual notification is made on the display device 31 of FIG. Here, only the rack end angle is notified as the steering wheel operation angle information because the steering wheel operation angle can be known to some extent from the sense of operation of the steering wheel 6 and only the highly important information is notified visually. This is to reduce the amount of information notified to the driver.
After the process of step A09 and when step A09 is NO, the road surface condition is estimated (step A10), and it is determined whether or not there is a change in the road surface condition (step A11).
If this step A11 is YES, the road surface condition is converted into image data (step A12), the display image of the road surface condition is updated (step A13), and the display device 31 of FIG. 4 or FIG. The driver is notified using an image that visually represents the estimated road surface condition using colors and figures.
On the other hand, when step A11 is NO, the road surface condition display image is not updated (step A14).
After the process of step A13 and the process of step A14, the program is ended (step A15).

  That is, in this embodiment, by reading vehicle information such as a steering wheel operation angle and a wheel steering angle, vehicle information that the driver cannot sensuously judge in the steering system 2 adopting the steer-by-wire system is displayed as an image to the driver. Can be notified visually. Further, by notifying the driver only of particularly important information, the driver's attention is prevented from going too far to the display device 31, and the amount of vehicle information (e.g., the driver's attention does not go too far to the display device 31) Sense that information can be read in an instant from a speedometer). Further, by notifying the road surface condition by visual recognition support based on the concept of “Sensitivity” (feeling degree), the steering system 2 adopting the steer-by-wire method notifies the driver of information such as the road surface condition that cannot be judged sensuously. In addition, by using this information, it is possible to improve the certainty and running performance of the steering system 2 adopting the steer-by-wire system.

Although the embodiments of the present invention have been described above, the configuration of the above-described embodiments will be described for each claim.
First, in the invention according to claim 1, there is provided a display device 31 having first display means 38 for displaying at least the steering direction and the steering amount of the steered wheels, and second display means 39 for displaying the road surface condition. .
Thereby, in the vehicle 1 having the steering system 2 adopting the steer-by-wire system, the driver can inform the actual state of the steered wheels and the road surface during driving, A highly reliable vehicle control system can be realized.
In the invention according to claim 2, the display device 31 is a device capable of visually recognizing the steering direction, the steering amount, and the change in the road surface condition of the steered wheels.
As a result, the driver can immediately see what the steering state and the road surface are just by looking at the display device 31, and thus the driver is not allowed to watch the display device more than necessary.
In the invention according to claim 3, the display device 31 is estimated when the steering angle (wheel steering angle) estimated from the detection value from the operation angle sensor 10 is the maximum steering angle (rack end angle). The fact that the steering angle has reached the maximum steering angle is displayed.
Thereby, since the display regarding the steering angle only displays that the steering wheel 6 has been rotated to the maximum steering angle which is the limit point of steering in the same direction, the contents of the display device 31 can be easily understood, This is simple, and can contribute to the realization of the steering system 2 that employs the steer-by-wire system that allows the driver to concentrate more on driving.

  A display device having at least first display means for displaying the steering direction and steering amount of the steered wheels and second display means for displaying the road surface condition can be applied to all vehicles equipped with a steering system.

It is a flowchart of the steering control for vehicles. It is a block block diagram of the steering control apparatus for vehicles. 1 is a system configuration diagram of a vehicle and a vehicle steering control device. It is a block diagram of the one display apparatus which notifies vehicle information. It is a block diagram of the other display apparatus which notifies vehicle information. It is a figure of the road surface condition measurement data (an example of an estimation method) regarding the road surface state estimation by a motor current. It is a figure which shows the example of the visual recognition assistance of the front vehicle by "Visibility" (degree of visibility). It is a figure which shows the example of the visual recognition assistance of the road surface by "Sensitivity" (degree to feel).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Steering system 3 Operation mechanism 4 Steering mechanism 6 Steering wheel 8 Reaction force generation mechanism 10 Operation angle sensor 12 Steering motor
DESCRIPTION OF SYMBOLS 18 Steering angle sensor 19 Steering motor 20 Vehicle steering control device 21 Control means 25 Vehicle information detection means 31 Display device 32 Road surface condition detection means 33 Steering amount calculation means 34 Vehicle information estimation calculation means 35 Road surface condition data calling means 36 Image data conversion Means 37 Maximum steering angle determination means 38 First display means 39 Second display means

Claims (3)

  Road surface condition detecting means for detecting an operation angle that is an angle at which the steering wheel is operated, a steering angle detecting means for detecting a steering angle of a steered wheel, and a road surface condition detecting means for detecting a road surface condition based on vehicle information And a vehicle steering control device provided with a control means provided with a steering amount calculation means for determining a steering amount of the steering wheel based on a steering angle detected by the steering angle detection means. A vehicle steering control device comprising a display device having first display means for displaying a direction and a steering amount, and second display means for displaying a road surface condition.   2. The vehicle steering control device according to claim 1, wherein the display device is a device capable of visually recognizing a steering direction, a steering amount, and a change in a road surface condition of the steered wheels.   The display device displays that the estimated steering angle has reached the maximum steering angle when the steering angle estimated from the detection value from the operation angle detection means is the maximum steering angle. The vehicle steering control device according to claim 2.

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