JP2647342B2 - Vehicle mileage detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed pulse obtained from a detection output of a vehicle speed sensor for detecting a traveling distance of a vehicle, a vehicle direction obtained from a direction sensor, and a GP.
The present invention relates to a device capable of correcting a pulse distance coefficient of the vehicle speed sensor and detecting an accurate traveling distance of a vehicle based on comparison with a change in position coordinates of the vehicle detected by an S receiving device.

[0002]

2. Description of the Related Art Conventionally, there has been known a navigation apparatus which is mounted on a vehicle, detects the position of a running vehicle, and performs driving support of the vehicle based on the detected vehicle position. This navigation device is provided with a vehicle speed sensor for detecting a vehicle speed pulse as a means for detecting a traveling distance of the vehicle. The travel distance is detected by the product of the number of vehicle speed pulses detected by the vehicle speed sensor and a preset pulse distance coefficient. For example, when 100 pulses are input from the vehicle speed sensor, the pulse distance coefficient set in the navigation device is 50 cm /
If it is a pulse, the traveling distance of the vehicle detected by the navigation device is 50 m.

A vehicle speed pulse obtained from a vehicle is input by converting the number of pulses generated when a mission (power transmission device) or a tire wheel makes one rotation into an electric signal, and its specifications differ depending on the vehicle. Therefore, the pulse distance coefficient varies from vehicle to vehicle. Also, the dynamic load radius of the tire attached to the vehicle (the apparent rolling radius of the tire calculated by dividing the distance traveled by the vehicle during one revolution of the tire during traveling of the vehicle by 2π; type of tire) Of course, it depends on the air pressure, etc.).

Conventionally, a navigation device has been mounted only on a vehicle limited as a maker option. Therefore, the specification of the vehicle speed pulse becomes a predetermined value, and the navigation device can accurately detect the traveling distance of the vehicle assuming that the dynamic load radius of the tire does not change.

[0005]

As described above, since the navigation device is mounted only on a limited vehicle, the specifications of the vehicle speed pulse are naturally limited. Therefore, the pulse distance coefficient set in the navigation device also has a specified value, and there is no need to calculate the pulse distance coefficient again.

[0006] However, in recent years, a navigation device has become commercially available as a single unit, and it has been demanded that the navigation device can be mounted not only on a limited number of vehicles but also on an unspecified number of vehicles. As described above, when the vehicle type on which the navigation device is mounted is unspecified, the specification of the vehicle speed pulse differs depending on the vehicle type. Therefore, a specific pulse distance coefficient cannot be set on the navigation device side.

Also, the dynamic load radius of the tire itself changes as the tire air pressure departs from the standard air pressure,
When a tire is replaced, it changes slightly even if the tire is replaced with a tire of the same standard. As a result, there is a problem that a correct traveling distance of the vehicle cannot be detected. The present invention has been made in view of the above technical problem, and an object of the present invention is to provide a vehicle mileage detection device that can calculate a pulse distance coefficient during traveling of a vehicle and detect the mileage of the vehicle with high accuracy. I do.

[0008]

Means and Functions for Solving the Problems (1) In order to achieve the above object, the vehicle traveling distance detecting device according to claim 1 applies the direction detected by the direction sensor to the pulse count of the vehicle speed sensor. A quadrature component adding means for obtaining quadrature components of the pulse count number of the vehicle speed sensor and independently adding the quadrature components; a linear distance traveled by the vehicle in two hours based on the position of the vehicle detected by the GPS receiver. , And in the section where the linear distance of the vehicle is determined by the GPS linear distance calculating means, the linear distance is calculated by the two orthogonal values of the pulse count of the vehicle speed sensor determined by the orthogonal component adding means. by comparing the root-sum-square of the components, viewed contains a pulse length coefficient calculating means for calculating the pulse distance factor, the pulse distance coefficient calculation hand
Constant stage, which retrospectively whenever traveling a certain distance d ₁
The orthogonal component added during traveling of the distance d ₂ (d ₂ > d ₁ )
Calculating the pulse distance coefficient based on the
You.

Applying the azimuth detected by the azimuth sensor to the pulse count of the vehicle speed sensor to obtain the orthogonal component of the pulse count of the vehicle speed sensor is input from the vehicle speed sensor at regular intervals. the pulse count _{n i (i = 1,2,3, ...} ) and, when the orientation of the time detected by the azimuth sensor and theta _i, to calculate the _{n i cos θ i, n i} sin θ i respectively That's what it means.

[0010] that is added to each seeking quadrature component independently refers to seek _{Σn i cos θ i, Σn i} sin θ i a (i = 1,2,3, ...). The orthogonal component is, specifically,
An east-west component (X component) and a north-south component (Y component) in the vehicle direction. _{Hereinafter, N x (j, k)} = Σn i cos θ i (i = j, j + 1, j + 2, ..., k), N y (j, k) (j, k) = Σn i sin θ _i (i = j, j + 1, j + 2,…,
k). Where N _x (j, k) and N _y (j, k) are 2
The sum between times (j, k) is taken.

On the other hand, when the position of the vehicle detected by the GPS receiver is written as (X _i , Y _i ),
The straight-line distance that the vehicle has moved to (j, k) is {(X _k −X _j ) ² + (Y _k −Y _j ) ² }. If this linear distance is written as D (j, k),
To calculate the pulse distance coefficient by comparing the square distance of the sum of squares of the two orthogonal components in the section where the linear distance D (j, k) is obtained, the ratio D (j, k) / √ That is, {N _x (j, k) ² + N _y (j, k) ² } is calculated.

In the vehicle travel distance detecting device having the above-described configuration, the direction detected by the direction sensor is applied to the pulse count of the vehicle speed sensor to obtain the orthogonal components of the pulse count of the vehicle speed sensor. Is added to. As a result, the added value of the X component and the added value of the Y component of the pulse count of the vehicle speed sensor are obtained.

On the other hand, the linear distance traveled by the vehicle between the two times is determined by the GPS receiver. The linear distance is calculated by the sum of the square of the added X component and the square of the Y component. It corresponds to the square root. Therefore, the straight distance
2 of the added value of the pulse count added during running
Calculate the pulse distance coefficient by dividing by the square root of the sum of squares
can do. Further, the pulse distance coefficient calculating means
Is certain that retroactive each traveling a certain distance d ₁
Quadrature component added during traveling of distance d ₂ (d ₂ > d ₁ )
The pulse distance coefficient is calculated based on
The calculation accuracy of the distance coefficient can be improved,
The number of times of calculating the pulse distance coefficient can be increased.

[0014]

[0015]

(2) The vehicle travel distance detecting apparatus according to claim 2 calculates a weighted average of the pulse distance coefficient calculated by the pulse distance coefficient calculation means and a pulse distance coefficient used in the past. And a pulse distance coefficient averaging means for adopting the averaged value as a pulse distance coefficient for detecting the traveling distance of the vehicle.

By performing weighted averaging in this way, the influence of short-term fluctuation of the pulse distance coefficient can be eliminated. However, by taking a weighted average,
A possible disadvantage is that the convergence of the Luth distance coefficient is slow.
But this drawback is past each time traveling "constant distance d ₁
Summing during running of the predetermined distance _{d 2 (d 2> d 1} ) that back to
Calculating the pulse distance coefficient based on the orthogonal component obtained.
Increase the number of times the pulse distance coefficient is calculated.
Can be solved.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 2 is a block diagram showing a configuration of the navigation device according to one embodiment of the present invention. This navigation device is mounted on a vehicle and used to support the traveling of the vehicle. This navigation device includes a wheel speed sensor 11, a gyro 12, a GP
External signals are obtained from the S receiving device 13 and these external signals are provided to the position detecting unit 14 in the navigation device main body. The gyro 12 is provided with an arithmetic unit 12a for integrating the angular velocity signals detected by the gyro 12.

The position detecting unit 14 is a memory drive 1
7, the road map data stored in the map dedicated disk D is obtained. The position detection unit 14 includes the gyro 12
The position of the vehicle is calculated from the azimuth information detected in step (1) and the traveling distance information detected by the wheel speed sensor 11. Since this calculation is performed at regular intervals (for example, 1.2 seconds),
The vehicle position is updated in this cycle as the vehicle travels.

Data representing the current position of the vehicle detected by the position detector 14 is provided to a controller 16 in the navigation apparatus main body. The control unit 16 is a control center of the navigation device main body, and based on the current position data detected by the position detection unit 14, the transit point data and the destination data input from the touch switch 19, and the road map data. Determine a route from your current location to your destination,
A road map, a vehicle current position mark on the map, and a line along a guidance route are generated and displayed on a liquid crystal display.

The position detecting section 14 includes a traveling distance detecting section 14a related to the present invention. The traveling distance detector 14a applies the azimuth detected by the gyro 12 to the pulse count of the wheel speed sensor 11 to obtain orthogonal components of the pulse count of the wheel speed sensor 11 and independently adds the components. The linear distance traveled by the vehicle between two times is calculated based on the position of the vehicle detected by the GPS receiver 13, and the square root of the linear distance and the sum of squares of the two orthogonal components is calculated in the section where the linear distance is calculated. The pulse distance coefficient is calculated by comparing with the above.

The running distance detecting section 14a for executing this function
FIG. 3 shows a functional block diagram of FIG. The orthogonal component calculator 1 calculates the orthogonal components n _i cos θ _i , based on the pulse count n _i input from the wheel speed sensor 11 at regular intervals and the azimuth θ _i at the same time detected by the azimuth sensor. _{n i sin θ i (n =} 1,2,3, ...) and to calculate respectively (see Figure 1 (b)).

The quadrature component adding unit 2, a quadrature component by adding _{each, Σn i cos θ i, Σn} i sin θ i (n = 1,2,3, ...) is determined. In this way, the orthogonal component addition unit 2 accumulates data as an addition value of the orthogonal component in all patterns that can travel normally as well as in a straight line. For example, when this addition continues during traveling of 200 m, the orthogonal component addition unit 2
Turns on the switch A and sends the added value to the GPS control unit 3. Hereinafter, the transmitted added value is written as N _x (j, k) and N _y (j, k) in the meaning of the added value at time (j, k).

On the other hand, the GPS control unit 3 calculates the sum N _x
The position coordinates (X _k , Y _k ) (see FIG. 1A) and the positioning accuracy at the time when (j, k) and N _y (j, k) are sent are stored. However, since the position detection accuracy of the GPS greatly changes depending on the reception state, when the positioning dimension becomes unstable due to becoming two-dimensional or three-dimensional, or when the SVC indicating the positioning accuracy is used.
When the ACC value or the DOP (Duration Of Precision) value is a certain value or more, the position coordinates (X _k , Y _k ) are not used. At this time, the GPS control unit 3 operates the switch B to send only the added values N _x (j, k) and N _y (j, k) to the orthogonal component storage unit (accumulator type memory) 4. When adopting the GPS position coordinates (X _k , Y _k ), the switch B is operated to send the added values N _x (j, k) and N _y (j, k) to the orthogonal component storage unit 4. , The position coordinates (X _k , Y _k ) of the vehicle detected by the GPS receiver 13 are sent to the GPS data storage unit 5.

The added value N _x stored in the orthogonal component storage unit 4
(j, k), N _y (j, k) and the position coordinates (X _k , Y _k ) of the vehicle stored in the GPS data storage unit 5 are determined by the distance determination unit 6
Sent to In the distance determination unit 6, the GPS data storage unit 5
If the distance between the two times (j, k) is determined to be a fixed distance, for example, 3 km, by retroactively moving back the data of the vehicle position coordinates (X _k , Y _k ) stored in Then, the data of the added values N _x (j, k) and N _y (j, k) at that time are sent to the pulse distance coefficient calculation unit 7. Incidentally, between 2 time (j, k) to the moved linear distance of the vehicle is calculated by the formula _{√ {(X k -X j)} 2 + (Y k -Y j) 2}.

The pulse distance coefficient calculation unit 7 divides the constant distance 3 km by the square root of the sum of squares of the addition values N _x (j, k) and N _y (j, k) to obtain a pulse distance coefficient α. Is calculated. That is, the ratio α = 3000 / √ (N _x (j, k) ² + N _y (j, k) ² ) [m / pulse] is calculated. Thus, the pulse distance coefficient α is calculated.

The pulse distance coefficient correction unit 8 stores the previously obtained pulse distance coefficient. If the newly obtained pulse distance coefficient is different from the previously obtained pulse distance coefficient, the previously obtained pulse distance coefficient is calculated. This is a part for correcting the obtained pulse distance coefficient to a correct value. In this way, the traveling distance detection unit 14a stores the previously stored section (for example, 200 m).
When the distance between the two GPS points is determined to be a certain value (for example, 3 km) from the amount of movement of the vehicle and the position coordinates of the GPS, the integrated value of the amount of movement (orthogonal component) of the vehicle during that time and G
The pulse distance coefficient is calculated and corrected from the distance between the two points of the PS, and provided to the position detection unit 14.

The position detecting unit 14 detects the corrected pulse
Using the product of the distance coefficient and the wheel speed pulse number,
The traveling distance of the vehicle can be detected. Fig. 4
Flowchart showing the outline of the pulse distance coefficient correction processing of FIG.
It is. Explaining step by step, the vehicle starts running.
Then, the contents of the orthogonal component storage unit 4 and the GPS data storage unit 5
Is eliminated (step S1), and the orthogonal component n_icos θ_i,
n _isin θ_iIs calculated, and the added value N_x(j, k), N_y(j,
k) is obtained (step S2). Fixed distance (200
m) When traveling (step S3), the GPS control unit 3
The GPS positioning accuracy is determined (Step S4). If you
If the degree is not good, the added value N_x(j, k), N_y(j, k) only
Is stored in the orthogonal component storage unit 4 (step S5). Spirit
If the degree is good, add value N_x(j, k), N_y(j, k)
And stores it in the minute storage unit 4 and based on the GPS data.
Vehicle position coordinates (X_k, Y_k) Is the GPS data storage unit
5 (step S6). The orthogonal component is
The sum is added in the intersection component storage unit 4 (step S7), and
The position coordinates of the vehicle based on the GPS data (X_k, Y_k)
The distance is determined by the distance determining unit 6 based on the distance.
(Step S8). The distance judging unit 6 calculates the GPS data
Is a certain distance from the previous determination
(3 km) (step S9),
Perform the division based on the above formula to calculate the pulse distance coefficient
(Step S11), the same coefficient obtained last time is supplemented.
Correct (step S12).

If the travel distance of the vehicle based on the GPS data has not reached 3 km from the previous determination, the distance determination unit 6 proceeds to step S10, where the orthogonal component storage unit 4 and the GPS data storage unit 5 It is determined whether or not there is stored data, and if there is stored data, the process returns to step S2 to continue the calculation of the orthogonal component and the like. In the description of the above flowchart, if the pulse distance coefficient is calculated (step S11) and the previously obtained coefficient is corrected (step S12), all the data is cleared and the processing is started again from the beginning. . However, after reaching a fixed distance of 3 km from the previous determination, the orthogonal component data newly obtained every 200 m is added without clearing the data, and subsequently, every 200 m, that is, 3.2 km, 3.4 km,
It is possible to calculate and correct the pulse distance coefficient by comparing the travel distance of the vehicle for the past 3 km with the distance between the two GPS points for each. By doing so, the number of times the pulse distance coefficient is corrected per traveling distance is increased, and the accuracy of the pulse distance coefficient can be further improved, as compared with the example of the flowchart in which the pulse distance coefficient can be corrected only every 3 km.

The pulse distance coefficient (step S12) corrected as described above is not used as it is, but is weighted and averaged with the pulse distance coefficient used in the past. The value may be a pulse distance coefficient. In this case, the pulse length coefficient A _n-1, which was last employed, when this corrected writing pulse distance coefficient alpha _n, the pulse distance coefficient A _n to adopt _{this, A n = (1-k} ) α n + KA _n-1 . However, the coefficient k takes a value from 0 to 1.

By its nature, the pulse distance coefficient does not change every time the vehicle travels for a short distance of about 200 m. Therefore, by adopting the averaged pulse distance coefficient A _n, it becomes possible to suppress a variation based on various measuring factors of the pulse distance factor can be obtained better results precision. Various modifications are conceivable in the above embodiment. For example, a vehicle speed sensor that detects a vehicle speed pulse of a vehicle may be a digital tachometer mounted on a shaft of a transmission or an engine, in addition to a wheel speed sensor mounted on a wheel. Gyro 1 as a direction sensor to detect the direction of the vehicle
A geomagnetic sensor or the like other than 2 may be used. Although the touch switch 19 is attached to the liquid crystal display, a remote control device may be provided separately from the liquid crystal display, and the switch 19 may be arranged on the remote control device.

The position detecting section 14 calculates the position information of the vehicle from the azimuth information detected by the gyro 12 and the traveling distance information detected by the wheel speed sensor 11,
The azimuth information detected by the gyro 12 and the wheel speed sensor 1
Even if the vehicle position is calculated based on a comparison between the travel distance information detected in step 1 and the road pattern stored in the map-dedicated disk D (so-called map matching method, see Japanese Patent Application Laid-Open No. 64-53112). Good.

[0033]

As is apparent from the above description, the vehicle traveling distance detecting device according to the first aspect has an azimuth sensor,
By using three types of sensors such as a vehicle speed sensor and a GPS receiver, a pulse distance coefficient for knowing the traveling distance of the vehicle can be accurately calculated and corrected. Therefore, when the navigation device is mounted on an unspecified number of vehicle types,
The pulse distance coefficient can be calculated accurately while the vehicle is running, even when the tire usage conditions change and without any special calibration procedure, so the vehicle travel distance is always detected with high accuracy. be able to.

Each time the vehicle travels a certain distance d ₁ ,
Summing during running of the predetermined distance _{d 2 (d 2> d 1} ) that back to
Calculating the pulse distance coefficient based on the orthogonal component obtained.
Therefore, the number of calculations can be increased, and the pulse distance coefficient
Can be made more accurate.

According to the vehicle traveling distance detecting device of the second aspect , the number of times of calculating the pulse distance coefficient can be increased.
In addition, by averaging the pulse distance coefficient,
Since the influence of the short-term fluctuation of the pulse distance coefficient can be removed, the traveling distance of the vehicle can be detected more accurately.

[Brief description of the drawings]

FIG. 1 (a) is a method of applying an azimuth detected by the azimuth sensor to a pulse count of a wheel speed sensor as a vehicle travels to determine an orthogonal component of the pulse count of the wheel speed sensor; FIG. 4 is a diagram illustrating a method for calculating a linear distance traveled by a vehicle between two times based on the position of the vehicle detected by a GPS receiver. (b) is an enlarged view for explaining a method for obtaining an orthogonal component of the pulse count number.

FIG. 2 is a block diagram showing a configuration of a navigation device according to one embodiment of the present invention.

FIG. 3 is a functional block diagram of a traveling distance detection unit.

FIG. 4 is a flowchart illustrating an outline of a pulse distance coefficient correction process.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 orthogonal component calculation unit 2 orthogonal component addition unit 3 GPS control unit 4 orthogonal component storage unit 5 GPS data storage unit 6 distance determination unit 7 pulse distance coefficient calculation unit 8 pulse distance coefficient correction unit 11 wheel speed sensor 12 gyro 13 GPS receiver

Claims (2)

(57) [Claims] An azimuth sensor for detecting an azimuth of a vehicle, a speed sensor for detecting a speed pulse of the vehicle, and a GPS for receiving a radio wave transmitted from a GPS satellite orbiting the earth orbit and detecting the position of the vehicle. A device for detecting a traveling distance of a vehicle by including a receiving device, wherein an azimuth detected by the azimuth sensor is applied to a pulse count of the vehicle speed sensor, and a quadrature component of a pulse count of the vehicle speed sensor is provided. Quadrature component adding means for obtaining the distance of the vehicle and calculating the linear distance that the vehicle has traveled in two hours based on the position of the vehicle detected by the GPS receiver; and the GPS linear distance. In the section where the straight-line distance of the vehicle is calculated by the calculating means, the straight-line distance is calculated by the pulse cow of the vehicle speed sensor calculated by the orthogonal component adding means. By comparing the root-sum-square of the two orthogonal components of the betting amount, seen including a pulse length coefficient calculating means for calculating the pulse distance factor, the pulse distance factor calculating means, to travel a certain distance d ₁
Every time a certain distance d ₂ (d ₂ > d ₁ )
The pulse distance based on the orthogonal component added during traveling
A vehicle travel distance detecting device for calculating a coefficient . 2. A weighted average of a pulse distance coefficient calculated by the pulse distance coefficient calculating means and a pulse distance coefficient adopted in the past, and the averaged value is used for detecting a traveling distance of a vehicle. 2. A pulse distance coefficient averaging means, which is used as a pulse distance coefficient of (1).
The vehicle travel distance detection device according to any of the preceding claims.