JPH07190797A - Gyro correction device for vehicle - Google Patents

Abstract

PURPOSE:To accurately correct the error of rate gyro output by correcting the reference level value at every preset time when a vehicle is judged to be in a turning stop condition. CONSTITUTION:A control means 1 detects the state of a vehicle from a speed sensor 2, and upon judging that the vehicle is in a stop condition, makes a correction for the reference level value of output from a rate gyro 4 on the assumption that a turning stop condition is existing, if the variation width of output from an earth magnetism sensor 3 is equal to or less than the preset value, and the variation width of output from the rate gyro 4 is equal to or less than the preset value. On the other hand, a means l judges that the vehicle is travelling along a expressway or a road dedicated to vehicles, upon judging that the vehicle is in travel mode, if the speed is equal to or larger than the preset value. Then, if the variation width of output from the sensor 3 and the variation width of output from the gyro 4 are both equal to or less than the preset values, the control means 1 judges that the vehicle is in a turning stop condition and makes a correction. In either case, the means 1 concurrently calculates the position and travel direction of the vehicle, on the basis of output from the sensors 2 and 3, and the gyro 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle gyro correction device, and more particularly to a vehicle gyro correction device suitable for a vehicle navigation system.

[0002]

2. Description of the Related Art In recent years, a navigation system using a rate gyro as an estimated navigation sensor has been mounted on a vehicle. However, the rate gyro output contains some error of the reference level called zero drift, as shown in FIG.

In the navigation system, the traveling azimuth of the vehicle is calculated by integrating the rate gyro output within a certain period of time. Therefore, the zero point drift of the rate gyro output causes an error in the calculation result.

In order to solve this problem, the following three measures have been published.

(1). A stop of the vehicle is detected and the reference level error is corrected from the rate gyro output at that time.

(2). The reference level error is corrected by detecting the stop of the vehicle and the turning stop of the vehicle (that is, when the rate gyro output is a constant value α or less and the variation is a constant value β or less).

(3). When the vehicle is traveling, the reference level error is detected when the road is straight and the vehicle is traveling straight (that is, when the rate gyro output is a constant value α or less and the variation is a constant value β or less). To correct.

[0008]

However, in the conventional example of the above (1), since the reference level is corrected by detecting only the stopped state of the vehicle, the vehicle has a turntable, a ferry, etc. in a parking lot. When the vehicle is placed on the vehicle, there is a disadvantage that the reference level is corrected even though the vehicle is turning.

In the conventional example of the above (2), since it is judged that the turning is stopped only when the output of the rate gyro is a constant value α or less, when the error of the reference level has already exceeded the constant value α. Had the inconvenience that the turning stop could not be detected.

Further, in the conventional example of the above (3), since it is determined that the vehicle is traveling straight when the rate gyro output is equal to or less than the constant value α, the error of the reference level has already reached the constant value α. If the vehicle is running over the straight line, it is not possible to detect straight running, and if the road on which the vehicle is running cannot be specified, there is the inconvenience that it cannot be dealt with.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gyro correction device for a vehicle, which is capable of correcting the disadvantages of the conventional example, and particularly capable of accurately correcting a reference level error of a rate gyro output in a vehicle navigation system. Is the purpose.

[0012]

According to the present invention, a vehicle speed sensor for measuring the traveling speed and traveling distance of a vehicle, a geomagnetic sensor for measuring the traveling direction of the vehicle, and a rate gyro for measuring the turning angle of the vehicle are provided. ing. Then, if it is determined from the geomagnetic sensor output and the rate gyro output that the vehicle is in a turning stop state, the reference level value of the rate gyro output is corrected at regular time intervals, and the vehicle speed sensor output, the geomagnetic sensor output, and the rate gyro output are changed. It is configured to include a control means for calculating the position and traveling direction of the vehicle based on the vehicle. This is intended to achieve the above-mentioned object.

[0013]

The control means detects the state of the vehicle from the vehicle speed sensor, and when it determines that the vehicle is stopped, if the variation width of the geomagnetic sensor output is less than a certain value and the variation width of the rate gyro output is less than a certain value, The reference level value of the rate gyro output is corrected assuming that the turning is stopped.

On the other hand, when it is determined that the vehicle is traveling, the control means determines that the vehicle is traveling on a highway or an automobile-only road if the speed between them is equal to or higher than a certain speed, and the variation range of the geomagnetic sensor output is If the rate gyro output change width is less than a certain value and less than a certain value, it is determined that the turning is stopped and the correction is performed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

First, referring to FIG. 1, in this embodiment, a vehicle speed sensor 2 for measuring the traveling speed and traveling distance of the vehicle, a geomagnetic sensor 3 for measuring the traveling direction of the vehicle, and a rate gyro for measuring the turning angle of the vehicle. 4, the output of the geomagnetic sensor 3 and the output of the rate gyro 4 determine that the vehicle is in a turning stop state, the reference level value of the rate gyro 4 output is corrected at regular time intervals, and the output of the vehicle speed sensor 2 and the output of the geomagnetic sensor 3 are performed. It is provided with a control means 1 for calculating the position and traveling direction of the vehicle from the output of the rate gyro 4.

As the vehicle speed sensor 2, for example, as shown in FIG. 2, a vehicle which uses a rotary gear attached to a driven wheel of a vehicle and a proximity sensor to output the rotation of the wheel in pulses is used. Then, the traveling speed and the traveling distance can be calculated by integrating the number of pulses within a certain period of time.

The geomagnetic sensor 3 detects the geomagnetism, and a fluxgate type geomagnetic sensor is generally used.

The rate gyro 4 detects the angular velocity, and the turning angle can be known by integrating the output value thereof.

The current traveling direction can be calculated from the turning angle and the previous traveling direction, and by considering the traveling direction obtained by the geomagnetic sensor 3, a highly reliable traveling direction can be obtained.

Next, the operation of the above embodiment will be described with reference to the timing chart of FIG. 3 and the flow charts of FIGS.

(1). As shown in the time position (A) of FIG. 3, when the ACC power is turned on in the stopped state (S51 of FIG. 5), the control means 1 determines the initial traveling direction of the vehicle based on the output value of the geomagnetic sensor 3. Ask (S5 in FIG. 5
2).

(2). Between time positions (A) and (B) in FIG. 3, the control means 1 controls the output value of the geomagnetic sensor 3, the output value of the rate gyro 4 and the output value of the vehicle speed sensor 2 by a timer interrupt process at regular time intervals. Read.
Then, the traveling speed and traveling distance of the vehicle are calculated from the output value of the vehicle speed sensor 2. Here, the sampling cycle of each output is set to a time sufficiently shorter than the behavior of the vehicle.

(3). As shown in the time position (B) of FIG. 3, before the traveling distance of the vehicle from the time position (A) of FIG. 3 reaches a preset specified traveling distance, the time position (A) of FIG. If the elapsed time from has reached the preset specified time (S61 in FIG. 6), the control means 1
Calculates the maximum traveling speed between the time positions “(A) and (B)” in FIG.

Then, since the maximum traveling speed is equal to or less than the preset speed value, it is determined that the vehicle is stopped (S62 in FIG. 6).

Here, the traveling speed is treated as a positive speed in both forward and reverse.

The control means 1 further obtains a variation width of the output value of the geomagnetic sensor 3 and a variation width of the output value of the rate gyro 4 between the time positions (A) and (B) of FIG.

Then, it is determined that the vehicle is not turning because these change widths are equal to or less than the preset values (S63 in FIG. 6).

At this time, since the vehicle is in a stopped state and is not turning, the traveling azimuth is the same as the previously calculated traveling azimuth and the vehicle position does not change (S64 in FIG. 6).

Further, the control means 1 calculates the average value of the output values of the rate gyro 4 between the time positions (A) and (B) of FIG. 3, and uses this average value as a new reference level of the output value of the rate gyro 4. The reference level value is corrected as a value (S68 in FIG. 6).

(4). Between the time positions (B) to (C) in FIG. 3, the control means 1 controls the output value of the geomagnetic sensor 3, the output value of the rate gyro 4 and the output value of the vehicle speed sensor 2 by the timer interrupt processing at regular time intervals. Read.
Then, the traveling speed and traveling distance of the vehicle are calculated from the output value of the vehicle speed sensor 2.

(5). As shown in the time position (C) of FIG. 3, before the elapsed time from the time position (B) of FIG. 3 reaches the preset specified time, the vehicle from the time position (B) of FIG. When the mileage reaches the preset specified mileage (S71 in FIG. 7), the control means 1 calculates the current traveling azimuth (θN) by the following equation (S77 in FIG. 7).

Θg = a · ∫g (t) dt + θ (N-1) ...

ΘN = k · θM + (1-k) · θg

Here, g (t) is the time position (B) in FIG.
Is the output value of the rate gyro 4 at the elapsed time t from, and θ (N-1) is the previous heading.

Further, θg is the traveling direction calculated from the previous traveling direction and the output value of the rate gyro 4 and θ M is the output value of the geomagnetic sensor 3. Further, the symbol a is a coefficient and the symbol k is
Is a weighting coefficient, which is obtained in advance from various measured values.

Further, the control means 1 described above uses the previous vehicle position [P (N-1) x, P (N-1) as shown in the following equation.
y] and mileage (LN), the current vehicle position [PN
x, PNy] is obtained (S78 in FIG. 7).

PNx = P (N-1) x + LN.cos θ (N
-1) ………

PNy = P (N-1) y + LN.sin θ (N
-1) ………

(6). Between the time positions (C) to (D) in FIG. 3, the control means 1 controls the output value of the geomagnetic sensor 3, the output value of the rate gyro 4 and the output value of the vehicle speed sensor 2 by a timer interrupt process at regular time intervals. Read.
Then, the traveling speed and traveling distance of the vehicle are calculated from the output value of the vehicle speed sensor 2.

(7). As shown in the time position (D) of FIG. 3, before the elapsed time from the time position (C) of FIG. 3 reaches the preset specified time, the vehicle from the time position (C) of FIG. When the mileage reaches the preset specified mileage (S71 in FIG. 7), the control means 1 uses the above equation to determine the current heading (θN).
Is calculated (S77 of FIG. 7).

Further, the control means 1 obtains the current vehicle position (PNx, PNy) by the above equation (S7 in FIG. 7).
8).

(8). Between time positions (D) to (E) in FIG. 3, the control means 1 controls the output value of the geomagnetic sensor 3, the output value of the rate gyro 4 and the output value of the vehicle speed sensor 2 by a timer interrupt process at regular time intervals. Read.
Then, the traveling speed and traveling distance of the vehicle are calculated from the output value of the vehicle speed sensor 2.

(9). As shown in the time position (E) of FIG. 3, before the elapsed time from the time position (D) of FIG. 3 reaches the preset specified time, the vehicle from the time position (D) of FIG. When the mileage reaches the preset specified mileage (S71 in FIG. 7), the control means 1 uses the above equation to determine the current heading (θN).
Is calculated (S77 of FIG. 7).

Further, the control means 1 obtains the current vehicle position (PNx, PNy) by the above equation (S7 in FIG. 7).
8).

(10). Time positions (E) to (F) in FIG.
In the meantime, the control means 1 reads the output value of the geomagnetic sensor 3, the output value of the rate gyro 4 and the output value of the vehicle speed sensor 2 by a timer interrupt process at regular intervals. Then, the traveling speed and traveling distance of the vehicle are calculated from the output value of the vehicle speed sensor 2.

(11). As shown in the time position (F) of FIG. 3, before the travel distance of the vehicle from the time position (E) of FIG. 3 reaches the preset specified travel distance,
When the elapsed time from the time position (E) reaches the specified time set in advance (S61 in FIG. 6), the control means 1 controls the time position (E) to (F) in FIG. Find the maximum running speed.

Then, since the maximum traveling speed is equal to or lower than the preset speed value, it is determined that the vehicle is stopped (S62 in FIG. 6).

The control means 1 further obtains the variation width of the output value of the geomagnetic sensor 3 and the variation width of the output value of the rate gyro 4 between the time positions (E) to (F) in FIG.

Then, since these change widths are equal to or less than the preset values, it is determined that the vehicle is not turning (S63 in FIG. 6).

At this time, since the vehicle is in a stopped state and is not turning, the traveling azimuth is the same as the previously calculated traveling azimuth, and the vehicle position does not change (S64 in FIG. 6).

Further, the control means 1 calculates the average value of the output values of the rate gyro 4 between the time positions (E) to (F) of FIG. 3, and uses this average value as a new reference level of the output value of the rate gyro 4. The reference level value is corrected as a value (S68 in FIG. 6).

However, since the reference level value is corrected at the time position (B) of FIG. 3, the time position (B) of FIG.
If the elapsed time from has not exceeded the preset time, the reference level value is not corrected (S67 in FIG. 6).

This is because the error of the reference level value of the rate gyro 4 generally does not occur in a short time, and unnecessary processing is reduced.

(12). Time positions (F) to (G) in FIG.
In the meantime, the control means 1 reads the output value of the geomagnetic sensor 3, the output value of the rate gyro 4 and the output value of the vehicle speed sensor 2 by a timer interrupt process at regular intervals. Then, the traveling speed and traveling distance of the vehicle are calculated from the output value of the vehicle speed sensor 2.

(13). As shown in the time position (G) of FIG. 3, before the traveling distance of the vehicle from the time position (F) of FIG. 3 reaches the preset specified traveling distance, the time position (F) of FIG. When the elapsed time from has reached the preset time set in advance (S61 in FIG. 6),
The control means 1 obtains the maximum traveling speed between the time positions (F) to (G) in FIG.

Then, since the maximum traveling speed is equal to or lower than the preset speed value, it is determined that the vehicle is stopped (S62 in FIG. 6).

The control means 1 further obtains the variation width of the output value of the geomagnetic sensor 3 and the variation width of the output value of the rate gyro 4 between the time positions (F) to (G) in FIG.

Then, it is determined that the vehicle is turning because these change widths are equal to or more than the preset values (S63 in FIG. 6).

Further, the control means 1 calculates the current traveling direction (θN) by the above equation (S6 in FIG. 6).
5). Further, the control means 1 obtains the current vehicle position (PNx, PNy) by the above equation (S66 in FIG. 6).

Next, the operation when the vehicle is traveling on a highway or a motorway will be described with reference to the timing chart of FIG.

When the vehicle is traveling on a highway or a motorway, as shown in FIG. 4, the traveling speed is continuously above a certain speed for a long period of time, and the vehicle speed from the previous time is calculated. Before the travel distance reaches the preset specified travel distance, the elapsed time from the previous calculation rarely reaches the preset specified time.

(1). Therefore, the control means 1 checks the traveling speed when the traveling distance of the vehicle from the previous calculation reaches the preset prescribed traveling distance (S71 in FIG. 7).

When it is determined that the traveling speed is continuously above a certain speed for a long time (S72, S7 in FIG. 7).
3) Then, the change width of the output value of the geomagnetic sensor 3 and the change width of the output value of the rate gyro 4 during that period are obtained.

(2). Then, the control means 1 compares these change widths with preset values.

(3). Here, if these change widths are equal to or smaller than the preset values, the control means 1 determines that the turning is stopped and corrects the reference level value of the rate gyro 4 output (S80 in FIG. 7). .

That is, the average value of the output values of the rate gyro 4 from the time of the previous calculation to the present time is calculated, and this average value is set as a new reference level value of the output value of the rate gyro 4.

However, as in the case of the time position (F) in FIG. 3, when a fixed time or more has not elapsed since the previous correction (S79 in FIG. 7) or when the ACC power supply has not been turned on again. Is not corrected.

The traveling azimuth of the vehicle is the same as the previously obtained traveling azimuth (S75 of FIG. 7), and the vehicle position is obtained from the previous traveling azimuth and the traveling distance (S76 of FIG. 7).

(4). On the other hand, in the process of (2) above, the width of change in the output value of the geomagnetic sensor 3 and the rate gyro 4
If the change width of the output value is equal to or larger than the preset value, the control means 1 determines that the vehicle is turning (S74 in FIG. 7), and the current traveling direction (θN) is calculated by the above equation. (S77 of FIG. 7), the current vehicle position (PNx, PNy) is calculated by the above equation (S7 of FIG. 7).
8).

As described above, the vehicle speed sensor 2 detects the state of the vehicle.
If the change width of the output of the geomagnetic sensor 2 is less than a certain value and the change width of the output of the rate gyro 4 is less than a certain value, it is determined that the turning is stopped and the reference of the rate gyro 4 output is detected. Correct the level value.

On the other hand, when it is determined that the vehicle is traveling, if the speed between them is equal to or higher than a certain speed, it is determined that the vehicle is traveling on an expressway or an automobile-only road, and the variation width of the output of the geomagnetic sensor 3 is less than a certain value. If the change width of the output of the rate gyro 4 is equal to or less than a fixed value, it is determined that the turning is stopped and the correction is performed.

However, once the reference level value of the rate gyro 4 output is corrected, the following values are satisfied until the above-mentioned correction conditions are satisfied after a predetermined time or more has passed or after the ACC power supply is turned on again. No correction work is performed.

[0074]

Since the present invention is constructed and functions as described above, the reference level error of the rate gyro output can be efficiently and accurately corrected according to the present invention. It is possible to provide an unprecedented excellent vehicle gyro correction device capable of highly accurately calculating the current position and traveling azimuth.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a specific example of FIG.

FIG. 3 is a first timing chart for explaining the operation of FIG.

FIG. 4 is a second timing chart for explaining the operation of FIG.

5 is a first flow chart for explaining the operation of FIG. 1. FIG.

FIG. 6 is a second flowchart for explaining the operation of FIG.

FIG. 7 is a third flowchart for explaining the operation of FIG.

FIG. 8 is an explanatory diagram for explaining zero-point drift of a rate gyro output.

[Explanation of symbols]

 1 Control means 2 Vehicle speed sensor 3 Geomagnetic sensor 4 Rate gyro

Claims (2)

[Claims] 1. A vehicle speed sensor for measuring a traveling speed and a traveling distance of a vehicle, a geomagnetic sensor for measuring a traveling direction of the vehicle, and a rate gyro for measuring a turning angle of the vehicle, the geomagnetic sensor output and the rate. It operates when it is determined that the vehicle is in a turning stop state based on the output that the gyro lacks, and performs the reference level value correction of the rate gyro output at regular time intervals, and the vehicle speed sensor output, the geomagnetic sensor output, and the rate. A gyro correction device for a vehicle, comprising a control means for calculating a position and a traveling direction of the vehicle from a gyro output. 2. The control means is provided with a correction stop function for stopping the correction of the reference level value for a certain period of time after the correction of the reference level value of the rate gyro output is executed. Item 1. A vehicle gyro correction device according to item 1.