JPH02301808A - Device for controlling running of moving vehicle - Google Patents

Abstract

PURPOSE:To obtain a device for controlling the running of a moving vehicle which can accurately control the running of the vehicle by calibrating the attitude angle of its own vehicle against an absolute reference. CONSTITUTION:The device is composed of a camera 10, picture memory 11, picture processing section 12, gyrocompass 13, interface 14, host computer 15, distance sensor 16, map storing section 17, running control section 18, steering actuator 19, and accelerator actuator 20. The device recognizes an azimuth against the reference direction of a prescribed picture from a picture for recognizing the outside after inputting the latter and calculates an attitude angle against the reference direction of its own vehicle from the azimuth. Then the device calibrates a reading value from the gyrocompass against the attitude angle and controls the running of the vehicle based on the attitude angle reading value. Thus the running of the vehicle can be controlled accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a travel control device for a moving vehicle equipped with a gyro compass for determining the attitude angle of the own vehicle with respect to a reference direction. Concerning improvements in methods for calibrating compass readings.

(Prior Art) In order to perform autonomous driving control or navigation driving, it is essential to know the traveling direction (i.e., attitude angle) of the own vehicle. Traditionally commonly used methods of determining the attitude angle include receiving specific radio waves from a ground station located at a predetermined location (Loran method) and receiving radio waves from an artificial satellite (GPS method). Or, there is a way to use a gyro compass.

The method of using a gyro compass is widely used due to the simplicity of the device. However, gyrocompasses are prone to errors. For example, a gyro compass that uses the coma principle is not affected by temperature changes, but the drift caused by the Earth's rotation causes a large error. Furthermore, in gas rate gyros and the like, temperature errors pose a major problem.

As a conventional technique aimed at correcting the error of this gyro compass, there is, for example, Japanese Patent Laid-Open No. 14212/1983. This patent application relates to the calibration of a rate gyro that is subject to offset and drift, such as a gas rate gyro. This rate gyro detects the rotation angle by measuring the turbulence in the gas flow caused by the rotation of the car body using two temperature sensors, and the offset correction described above is stopped due to the solid characteristics of the sensor. This is necessary because the sensor outputs an analog output even when the sensor is in use. Further, the 1 to lift correction is necessary because the offset value itself changes with the temperature change of the gyro body.

The calibration in this patent application involves completely stopping the vehicle at regular intervals and resetting the gyro at that time. In other words, if the vehicle is at a complete stop, the outputs from the two temperature sensors must be equal, and if they are out of balance, it is all a result of offset and drift, so this unbalance can be If used as the offset correction value or drift correction value,
This rate gyro will be calibrated.

However, the calibration in JP-A-62-142], No. 2 is not a calibration with respect to an absolute standard, but only a relative calibration. This is because errors have been accumulated in the trajectory traveled before the reset 1, so the position and attitude angle of the own vehicle at the point where the reset was performed will include errors. Therefore, even if it is possible to reduce the amount of error that will occur during future driving by performing a reset, it is not possible to cancel errors that have occurred in the past.

Therefore, as a method to correct errors caused by temperature changes and the rotation of the earth not only relatively, but also against an absolute standard, the vehicle is placed in a specific booth whose orientation and position are known. A method of resetting the device by making it stand still has also been proposed.

(Problem to be Solved by the Invention) However, the method of calibrating the attitude angle with respect to an absolute standard by stopping the vehicle in this specific booth and resetting it is difficult to calibrate the attitude angle with respect to an absolute standard, This can only be applied if a booth can be prepared, and is virtually impossible on general roads. Furthermore, even if a vehicle equipped with a gyro compass is used in an area where such a special booth has been prepared, the vehicle must be moved to the special booth, and it is not possible to reset the gyro compass at any time.

On the other hand, it is possible to know the absolute attitude angle using the above-mentioned Laurent method or GPS method, but as mentioned above, there are problems in terms of cost and scale.

Therefore, the present invention was proposed in order to eliminate the drawbacks of the above-mentioned conventional examples. The purpose of the present invention is to propose a travel control device for a mobile vehicle that enables accurate travel control by controlling the vehicle speed.

(Means and operations for achieving the object) As shown in FIG. 1, the structure of the present invention for achieving the above object includes a gyro compass for determining the attitude angle of the own vehicle with respect to a reference direction. In a moving vehicle, an image human input means for inputting an image for recognizing the outside world, a direction recognition means for recognizing the orientation of a predetermined image with respect to the reference direction from the manually input image, and a recognized orientation of the predetermined image. Attitude angle calculation means for calculating an attitude angle of the own vehicle with respect to a reference direction from
Calibration means for calibrating the read value from the gyro compass based on the attitude angle of the own vehicle with respect to the reference direction;
The present invention is characterized by comprising a travel control means that performs travel control based on the read value of the calibrated attitude angle.

Since the direction of the predetermined image with respect to the reference is known, the orientation of this predetermined image with respect to the reference direction obtained by image processing and the orientation obtained from the recognized orientation of this predetermined image are What is the attitude angle of the car relative to the reference direction?
It reflects the error of the gyro compass and can calculate the error.

(Example) With reference to the accompanying drawings, the present invention was applied to a travel control system that detects an attitude angle using a gyro compass that utilizes the top principle and performs travel control based on this attitude angle. An example will be explained.

FIG. 2 is a block diagram of the travel control system of this embodiment. In the figure, a camera 10 captures images of the outside world and stores the images in an image memory 11. Reference numeral 12 denotes an image processing section that performs predetermined image processing on the images stored in the image memory 11. Reference numeral 13 denotes a gyro compass using a top, which outputs a signal indicating how many times it has rotated with respect to a reference. This signal is the interface 14
is converted into a digital value by the host computer 1.
It will be incorporated into 5.

A distance sensor 16 is attached to a wheel or the like and detects the distance traveled. 17 is a map storage device that stores map information and the like. ] 8 is a travel control unit, which manually calculates the attitude angle and travel distance calculated by the host computer 15.
The steering actuator 19 and the accelerator actuator 20 are controlled to perform steering control and vehicle speed control.

In the travel control system shown in FIG. 2, the post computer 15
or recognize the vehicle's location.

(2) The host computer 15 compares the recognized vehicle position with the map information stored in the map storage device 17 and creates a trajectory. Then, the steering angle and the accelerator opening are calculated from the trajectory and the attitude angle of the vehicle and are sent to the travel control unit 18.

(2) Calibrate the gyro 13 at a predetermined timing.

In this embodiment, the predetermined timing of (2) is the distance sensor 1.
This is when the cumulative travel distance detected in step 6 reaches a certain value. Note that this predetermined timing is determined by the host computer 1.
5 may be detected to be inconsistent with the map information stored in the map storage section 17 (for example, the recognized vehicle position is not on the road).

Calibrate the gyro in ■ as follows. For example, a tangled edge of a road is detected from the image obtained by the camera 10. Also,
Estimate the current location of your vehicle. To estimate this position, from the distance traveled per unit time and the attitude angle of the vehicle per unit time, the distance traveled per unit time in the X direction and Y direction △X and △Y is N, and these are integrated. It can be obtained by The map storage unit 17 is also searched to select the road closest to the estimated position. Next, by comparing the direction of that road (the direction of the road obtained from this map is absolutely correct unless you search for the wrong road) and the direction of the road's tangled edges obtained through image processing. , calibrate the gyro compass 13.

This calibration is possible because the direction of the tangled edge obtained by the image processing described above is based on the coordinate system on which the gyro compass depends.

FIGS. 3A and 3B are diagrams explaining the principle of this calibration. FIG. 3A shows an image of a road obtained when the gyro compass 13 has no error. At this time, it is assumed that the vehicle is at an attitude angle θ with respect to the north pole of the earth's magnetic field. In other words, the road your car is on is offset by 0 degrees from the north pole,
The own vehicle is located parallel to this road. At this time,
A reading value θ is obtained from the gyro compass 13. If the vehicle is located in the center of the road, the camera 10 is installed in the center of the vehicle, and its optical axis extends in front of the vehicle, the image stored in the image memory 11 The tangled ends are shown in FIG. 3A. In other words, the ends AB and CD are symmetrical about the center line xx of the image memory. When a reverse perspective transformation is applied to the image of this tied edge, since the own vehicle is located parallel to the road, the angle of the tied edge with respect to the optical axis of the camera is 0 degrees. The attitude angle with respect to the pole is θ.

FIG. 3B shows a case where the gyro compass 13 has an error and the vehicle comes to the same position as FIG. 3A.

Using a gyro compass with an error, the attitude angle is 0 degrees with respect to the north pole (actually, due to the error, it is θ degrees)
Even if one's own vehicle is placed on the road so that Since the own vehicle is tilted by α degrees with respect to the road, the images of the tangled ends are A'B' and C'D', as shown in Fig. 3h. If the images A'B' and C'D' of the tied ends are subjected to inverse perspective transformation as in the case of FIG. 3A, the attitude angle α of the own vehicle with respect to the road can be detected. In other words, because the gyro compass has a reading error △θ (-〇“-〇), the reading value of the gyro compass 13 becomes θ even though the attitude angle with respect to the earth's magnetism is actually θ°. As a result, the attitude of the own vehicle relative to the road shifts by 0 degrees, so 80=a. Therefore, let this a be the subsequent correction value, and if
If the gyro compass reading is 01 degrees, then N
The official attitude angle with respect to the pole is θ1+Δθ degrees.

FIG. 4 is a flowchart showing the control procedure, which is executed by the host computer 15. Step S
In step 2, it is first determined whether to correct the gyro compass. As mentioned above, this is when the cumulative travel distance detected by the distance sensor 16 reaches a certain value, or
This is when it is detected that the position of the own vehicle recognized by the post computer 15 is inconsistent with the map information stored in the map storage section 17 (for example, the recognized position of the own vehicle is not on the road).

If it is determined that it is not the time to perform correction, the process proceeds to step 320 and subsequent steps, and travel control is performed based on the gyro read value. That is, in step S20, the instruction value 01 of the gyro compass 13 is read, and in step S22, the previously calculated correction value Δθ is added to this θl. That is,
Obtain θ1+△θ as a calibration value for the direction of the own vehicle. Based on this calibration value, predetermined travel control is performed in step S24. That is, the host computer 15 recognizes the vehicle position based on this θ1+Δθ and the travel distance obtained from the distance sensor 16, and then stores the recognized vehicle position in the map storage device 17. The steering angle and accelerator opening are sent to the travel control unit 18 based on the attitude angle of the own vehicle after checking with the map information.

If it is determined in step S2 that it is time to perform correction, the process proceeds to step 84 and subsequent steps.

First, in step S4, an image is input. Step S
In step 6, image processing such as binarization processing and labeling is performed to extract an image of a reference object indicating the direction of a tangled end or the like. Then, in step S8, the attitude angle α of the own vehicle with respect to this reference object is calculated. If the attitude of the own vehicle with respect to the road when reading the image in step S2 is set to α° based on the measurement results of the gyro compass up to that point, then α−α.

becomes the error component Δθ. In step S]O, a correction value is calculated based on this formula.

In addition, in FIG. 3B, the explanation was made assuming that α°=O (that is, it was assumed that the own vehicle was placed parallel to the road, although there was an error). This Δθ is subsequently used as a correction value in step S22.

In this way, according to the embodiment described above, it is possible to calibrate the attitude angle of the own vehicle with respect to the north pole of the earth's magnetic field, that is, to obtain the attitude angle of the own vehicle with respect to the absolute standard. Based on this accurate attitude angle, accurate travel control, such as forward vehicle following control, navigation travel control, etc., becomes possible.

The present invention can be modified in various ways without departing from the spirit thereof.

For example, in the control procedure shown in FIG. 4, each time the indicated value of the gyro compass 13 is read, correction is performed in step S22. may send the corrected reading to the host computer 15.

Further, in the embodiment shown in FIG. 2, the direction of the road is known from the map information stored in the map storage section 17. Instead of doing this, it is also possible, for example, to recognize a utility pole in an image and determine the azimuth angle of the vehicle relative to the N pole from the direction of the shadow of the utility pole. This is because the shadow of a telephone pole is a fixed value regardless of the season or longitude if the latitude and time of the own vehicle are known.

In addition, in the above embodiment, an embodiment was described for the purpose of correcting the attitude angle with respect to the geomagnetic N pole, that is, calibrating the attitude angle with respect to the absolute reference direction.
Similar to No. 2-1.4212, the present invention can also be applied when the purpose is calibration with respect to a relative standard. That is, in the above embodiment, as explained in connection with FIGS. 3A and 3B, the road on which the own vehicle is placed when capturing the image is
It is assumed that the direction of extension of the north pole is known.

By doing this, it was possible to detect the error of the gyro compass by detecting from the image how far the own vehicle deviates from the road. Therefore, even if the azimuth angle with respect to the N pole of the road is not known, for example, if the vehicle is placed parallel to the road, the reading value of the gyro compass at that time will directly indicate the error of the gyro compass. This makes it possible to detect relative errors.

(Effects of the Invention) As explained above, the traveling control device for a mobile vehicle of the present invention has the following features:
In a mobile vehicle equipped with a gyro compass for determining the attitude angle of the own vehicle with respect to a reference direction, an image input means for inputting an image for recognizing the external world, and a means for inputting a predetermined image from a manually generated image relative to the reference direction. a direction recognition means for recognizing the bearing; an attitude angle calculation means for calculating the attitude angle of the host vehicle relative to the reference direction from the recognized direction of the predetermined image; The present invention is characterized by comprising a calibration means for calibrating the read value from the gyro compass, and a travel control means for performing travel control based on the calibrated attitude angle read value.

Since the direction of the predetermined image with respect to the reference is known, the orientation of this predetermined image with respect to the reference direction obtained by image processing and the orientation obtained from the recognized orientation of this predetermined image are What is the attitude angle of the car relative to the reference direction?
It reflects the error of the gyro compass and can calculate the error. Therefore, it is possible to easily know the error of the Lushiro compass with respect to the reference direction in this way, it is possible to obtain an accurate attitude angle, and accurate travel control is possible.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of the present invention, Fig. 2 is a block diagram showing the configuration of an embodiment system to which the present invention is applied, and Figs. 3A and 3B are corrections to gyrocompass reading values in the embodiment. FIG. 4 is a diagram explaining the principle of the value derivation method, and is a flowchart showing the control procedure of the embodiment. In the figure, 10...camera, 11...image memory, 12...
Image processing unit, 13... Gyro compass, 14...
Interface, 15...Host computer, 1
6...Distance sensor, 17...Map storage unit, 18.
... Travel control unit, 19... Steering actuator, 2°... Accelerator actuator. Ward's

Claims (1)

[Claims] (1) In a mobile vehicle equipped with a gyro compass for determining the attitude angle of the own vehicle with respect to a reference direction, an image input means for inputting an image for recognizing the outside world, and a predetermined image from the input image. a direction recognition means for recognizing the orientation with respect to the reference direction; an attitude angle calculation means for calculating the attitude angle of the host vehicle with respect to the reference direction from the recognized orientation of the predetermined image; a calibrating means for calibrating the read value from the gyro compass based on the calibrated attitude angle read value, and a travel control means for controlling the travel based on the calibrated attitude angle read value. Control device.