JPH04250312A - Disturbance correcting method for on-vehicle direction finder - Google Patents

Abstract

PURPOSE:To eliminate the need for troublesome adjusting operation to enhance the commodity value. CONSTITUTION:A specified current energizes an X correcting coil to generate a test vector (r) going from point A0 toward point A1. Next, the coordinates (Xa, Ya) of the point A0 are determined from Xa=a1.r/(a0-a1), Ya=a0.a1.r/(a0-a1). Further, a vehicle is reversed by 180 degrees, and the coordinates (Xb, Yb) of point B are determined in the same manner. Taking P=((Xa+Xb)/2, (Ya+Yb)/2), an electromagnetic vector OP is obtained to determine a correcting magnetic vector.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted compass that indicates the heading direction of a vehicle, and relates to a disturbance correction method for correcting errors in the heading indication caused by disturbances such as magnetization of the vehicle.

0002

2. Description of the Related Art Conventionally, as this type of vehicle-mounted direction meter, a direction meter whose direction sensor section is shown in FIGS. 2 and 3 has been proposed. That is, FIG. 2 is a plan view of the orientation sensor section, and FIG.
It is an I line sectional view. In these figures, reference numeral 1 denotes a magnetic disk that rotates freely according to the earth's magnetic direction, and is magnetized so that when the magnetic flux is measured along the outer periphery, the strength of the magnetic field becomes sinusoidal. 2-1 and 2-2 are Hall elements arranged oppositely on the outer peripheral surface of the magnet disk 1 with a phase difference of 90°; 3 is a Y-direction correction coil that generates a correction magnetic vector in the longitudinal direction of the vehicle; and 4 is a correction coil for the vehicle. This is an X-direction correction coil that generates a correction magnetic vector in the left-right direction.

FIG. 4 shows a circuit for extracting voltage signals from this direction sensor section. That is, the Hall elements 2-1 and 2-2 detect the X-direction component and the Y-direction component of the magnetic pole position of the magnet disk 1 as the amount of magnetic flux. The X-direction component and the Y-direction component detected by the Hall elements 2-1 and 2-2
The direction component magnetic pole position detection signal is amplified by amplifier circuits 5-1 and 5-2, and SX=A・sinθ and SY
= A·cos θ is output as a voltage signal. however,
A is a constant, and θ is the magnetic pole direction of the magnet disk 1 and the Y direction (
indicates the angle formed with the direction of travel). Therefore, by determining θ from the voltage signals SX and SY obtained from the amplifier circuits 5-1 and 5-2, the direction of travel of the vehicle can be indicated on a display section (not shown).

However, the X-direction component and Y-direction component magnetic pole position detection signals detected by the Hall elements 2-1 and 2-2 are affected by the magnetization of the vehicle. That is, since vehicles are generally made of steel, they can be considered a type of magnet, although the amount of magnetization varies. The influence of this magnetization on the vehicle will be explained using FIG. 5. The orientation sensor unit attached to the vehicle detects the geomagnetic vector PA0 and the vehicle's magnetization vector OP.
Detect the composite vector OA0. geomagnetic vector P
Since the amount of A0 is very small, the magnetization vector OP
cannot be ignored, and the error Φ shown in the figure will occur,
Significantly deteriorates the accuracy of direction meter indication.

[0005] An X-direction correction coil 4 and a Y-direction correction coil 3 are provided for the purpose of preventing this deterioration of pointing accuracy. That is, by supplying an appropriate amount of current to the X-direction correction coil 4 and the Y-direction correction coil 3 to generate a correction magnetic vector that is opposite in direction and equal in size to the magnetization vector OP, the magnetization vector OP can be canceled. This makes it possible to offset errors that occur in direction indication.

[0006] In order to obtain this corrected magnetic vector, conventionally, a method as shown in the following steps (1) to (4) has been adopted. ■Align the vehicle to the north. ■Adjust the current supplied to the X-direction correction coil 4 so that the direction indicator points north. ■Move the vehicle towards the east. ■Adjust the current supplied to the Y-direction correction coil 3 so that the compass points to the east.

[0007]

[Problems to be Solved by the Invention] However, this conventional method for deriving a corrected magnetic vector has the following problems from the viewpoint of general users. ■It is difficult to align the vehicle accurately to the north or east. (2) The magnet disk 1 rotates due to changes in the current supplied to the X-direction correction coil 4 and the Y-direction correction coil 3, but it is necessary to adjust at an appropriate speed in consideration of the response delay of the magnet disk 1. Adjusting this speed to an appropriate speed is difficult. ■As automated systems become more widespread, manual adjustment reduces the product value itself.

[0008]

[Means for Solving the Problems] The present invention has been made to solve the above problems, and it supplies a specified current to a correction coil to create a test magnetic field, and calculates coordinates corresponding to the detected traveling direction at this time. Find the point as the first coordinate point, then reverse the vehicle and perform the same operation to find the second coordinate point,
The disturbance magnetic field is obtained with reference to these first coordinate points and second coordinate points, and the correction magnetic field is determined.

[0009]

[Operation] Therefore, according to the present invention, it is possible to obtain the disturbance magnetic field by processing calculations using a CPU or the like using the first coordinate point and the second coordinate point as reference, and to automatically determine the correction magnetic field. Become.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS A disturbance correction method for a vehicle-mounted compass according to the present invention will be explained in detail below. FIGS. 1A and 1B are vector diagrams for explaining one embodiment of this disturbance correction method. In FIG. 1(a), it is assumed that the vehicle is in a stopped state, and the direction meter detects the direction of a vector from the origin O to the point A0 as the traveling direction. Further, in this embodiment, the orientation sensor section has the same configuration as that shown in FIGS. 2 and 3.

First, in the state shown in FIG. 1(a), a specified current is applied to the X-direction correction coil 4 to create a test magnetic field.
A test vector r directed from point A0 to point A1 is generated. Then, the direction meter detects the direction of the vector from the origin O to the point A1 as the traveling direction.

[0012] Here, the coordinates (Xa, Ya) of point A0 are
It is determined by equations (1) and (2) shown below. Xa=a1・r/(a0-a1)...(1) Ya=a
0・a1・r/(a0-a1)...(2)

0013
] The above equations (1) and (2) were derived through the following process. The coordinates of point A0 are A0=(
Xa, Ya), and the coordinates of point A1 are A1=(X
a+r,Ya). If we create a linear equation for a straight line passing through the origin O and point A0, it is expressed as Y=a0・X (3). However, a0=Ya/Xa. Therefore, at point A0, Ya is Ya=a0・X
a...It is shown as (4). Similarly, if we create a linear equation for a straight line passing through the origin O and point A1, it is expressed as Y=a1·X (5). However, a1=Ya/(Xa+r). Therefore, at point A1, Ya is expressed as Ya=a1・(
Xa+r) ... (6). That is, from the above equations (4) and (6), Ya=a0・Xa=a1・(Xa+r)...(7
) holds, and if we expand this equation (7), we will find Xa=a1・r/(a0−a1) as the above equation (1), and Ya=a0・a1・r as the above equation (2). /(a0-a
1) is found.

Next, with the vehicle rotated 180 degrees,
That is, with the vehicle reversed, a test vector r directed from point B0 to point B1 is generated as shown in FIG. 9) Calculate using formula. Xb=b1・r/(b0-b1)...(8) Yb=b
0・b1・r/(b0-b1)...(9)

0015
] As can be seen from FIGS. 1(a) and (b), the end point P of the magnetization vector is located at the midpoint between point A0 and point B0, so P=((Xa+Xb)/2, (Ya+Yb)/2 )
...It is found as (10). Therefore, the above (
By substituting each value into equations 1), 2), 8), and 9 to obtain Xa, Xb, Ya, and Yb, the magnetization vector O
P can be obtained, and a correction magnetic vector that cancels out this magnetization vector OP can be determined.

A limiting factor in this method is that the vehicle
It is only necessary to reverse the position by 80 degrees, and there is no need to adjust the vehicle to a prescribed direction as shown in the conventional example, thereby simplifying the magnetization correction operation of the vehicle. In addition, it is easy to configure this method on a system using a CPU,
It is possible to determine the magnetization vector OP through processing calculations using the CPU and automatically determine the corrected magnetic vector, making difficult adjustment work unnecessary and increasing the product value.

Note that in the above-mentioned embodiment, the origin O
Vector from to point A0 (B0) and from origin O to A1
Although the vectors directed toward point (B1) are employed and the coordinate point A0 (B0) is determined from the angle formed by these vectors, the vectors to be employed are not limited to these. That is, from the origin O to A0 (B0) to A4 (B4
) The coordinate point A0 (B0) can be found by selecting any two of the five types of vectors directed toward the point and solving the simultaneous equations.

Ten sets of solution equations are shown below. A0=(x0, y0) Equation passing through origin O and A0 → y=a0・x...(a) A1=(x0+r,
y0) Equation passing through origin O and A1 → y=a1・x・
...(b) A2 = (x0, y0+r) Origin O and A2
Equation passing through → y=a2・x...(c) A3=(x0
-r, y0) Equation passing through origin O and A3 → y=a3
・x...(d) A4=(x0, y0-r) Origin O
The equation passing through A4 and A4 is defined as y=a4・x...(e).

From equation (a), y0=a0・x0 From equation (b), y0=a1・(x0+r) From equation (c), y0+r=a2・x0 From equation (d), y0=a3・(x0 -r) From formula (e), y0-r=a4・x0

[0020] Using equations (a) and (b), a0 x0 = a1 x (x0 + r) x0 = a1 r/(a0 - a1), y0 = a0 a
1・r/(a0-a1)...(I) (A) formula and (C)
According to the formula, a0・x0+r=a2・x0
x0=r/(a2-a0), y0=a0・r/(a2-
a0)...(II)

[0021] Using equations (a) and (d), a0 x0 = a3 x (x0-r) → (a0-
a3)・x0=-r x0=a3・r/(a3-a0)
, y0=a0・a3・r/(a3−a0)...(II
I) By equations (a) and (e), a0・x0−r=a4・x0→(a0−
a4) x0=r x0=r/(a0-a
4), y0=a0・r/(a0-a4)...(IV)
By equations (b) and (c), a1・(x0+r)+r=a2・x0→(a1
-a2)・x0=(1+a1)・r x0=(1
+a1)・r/(a2-a1), y0=a1・(x0+
r)...(V) From equations (b) and (d), a1・(x0+r)=a3・(x0−r)→(a1−a
3)・x0=-r・(a1+a3)x0=(a1+a3
)・r/(a3-a1), y0=a1・(x0+r)・
...(VI) By equations (b) and (e), a1・(x0+r)−r=a4・x5→(a1−
a4)・x0=r・(1-a1) x0=(1-a
1)・r/(a1-a4), y0=a1・(x0+r)
...(VII) By equations (c) and (d), a3・(x0-r)+r=a2・x0→(a3-a
2)・x0=r・(a3-1) x0=(a3-1)
・r/(a3-a2), y0=a3・(x0-r)...
・(VIII) By equations (c) and (e), a2・x0−r=a4・x0+r→(a2
-a4)・x0=2r x0=2・r/(a
2-a4)...(IX)a4・(y0+r)=a2・
(y0-1) → (a4-a2)・y0=-r・(a2+
a4) y0=a2・x0−r From equations (d) and (e), a3・(x0−r)−r=a4・x0→(a3
-a4)・x0=r・(1+a3) x0=(1
−a3)・r/(a3−a4), y0=a3・(x0−
r)...(X)

Regarding the magnetization correction calculation, a case where an error occurs in which the denominator of the calculation formula becomes 0 will be explained below. (2) A case where the denominator becomes 0 in the calculation for calculating the slope occurs when the A0 point or the B0 point approaches the Y axis. (2) A case where the denominator becomes 0 in the calculation to obtain the A0 point or the B0 point occurs when any of the 10 combinations of a0 to a4 have the same value. This also applies to b0 to b4. Next, the processing method in each case will be described with reference to Tables 1 to 30. As a representative way to read these tables, if Table 31 is shown as a representative, the formulas that cause errors in this table are: ■A0, A1... (I) formula, ■
A0, A3...(III) formula, A1, A3...(V
I) It is seen as the formula.

[0023]

[Table 31]

Furthermore, as a processing method, (1) When point P is the origin...If all of the equations (I) to (X) are errors, the process is performed assuming that it is the origin. ■P point is X
If it is on the axis...Equations (I), (III), and (VI) will result in an error, so these will be removed from the process. ■If point P is on the Y-axis...All expressions other than formula (VI) will result in an error. Find the P point using only the VI formula.

1. A0 is the origin B0 is any point on the X axis (
(Does not exist at the origin) See Tables 1 and 2

[0026]

[Table 1]

[0027]

[Table 2]

2. A0 is the origin B0 is any point on the Y axis (
(Does not exist at the origin) See Tables 3 and 4

[0029]

[Table 3]

[0030]

[Table 4]

3. A0 is the origin B0 is any point other than on the X and Y axes See Tables 5 and 6

[0032]

[Table 5]

[0033]

[Table 6]

4. A0 is any point on the X axis (does not exist at the origin) B0 is the origin See Tables 7 and 8

[0035]

[Table 7]

[0036]

[Table 8]

5. A0 is any point on the X-axis (does not exist at the origin) B0 is any point on the X-axis (does not exist at the origin) See Tables 9 and 10

[0038]

[Table 9]

[0039]

[Table 10]

6. A0 is any point on the X axis (does not exist at the origin) B0 is any point on the Y axis (does not exist at the origin) See Tables 11 and 12

[0041]

[Table 11]

[0042]

[Table 12]

7. A0 is any point B on the X axis excluding the origin
0 is any point other than on the X and Y axes See Tables 13 and 14

0
044]

[Table 13]

[0045]

[Table 14]

8. A0 is any point on the X axis (does not exist at the origin) B0 is the origin See Tables 15 and 16

[0047]

[Table 15]

[0048]

[Table 16]

9. A0 is any point on the Y axis (does not exist at the origin) B0 is any point on the X axis (does not exist at the origin) See Tables 17 and 18

[0050]

[Table 17]

[0051]

[Table 18]

10. A0 is any point on the Y axis (does not exist at the origin) B0 is any point on the Y axis (does not exist at the origin) See Tables 19 and 20

[0053]

[Table 19]

[0054]

[Table 20]

11. A0 is an arbitrary point on the Y axis (does not exist at the origin) B0 is an arbitrary point other than on the X and Y axes Table 21,
See Table 22

[0056]

[Table 21]

[0057]

[Table 22]

12. A0 is any point B except on the X and Y axes
0 is the origin See Tables 23 and 24

[0059]

[Table 23]

[0060]

[Table 24]

13. A0 is any point B except on the X and Y axes
0 is any point on the X axis (excluding the origin) See Tables 25 and 26

[0062]

[Table 25]

[0063]

[Table 26]

14. A0 is any point B except on the X and Y axes
0 is any point on the Y axis (excluding the origin) See Tables 27 and 28

[0065]

[Table 27]

[0066]

[Table 28]

15. A0 is any point B except on the X and Y axes
0 is any point other than on the X and Y axes, see Tables 29 and 30

0
068]

[Table 29]

[0069]

[Table 30]

[0070]

Effects of the Invention As is clear from the above explanation, according to the present invention, the disturbance magnetic field is determined by processing calculations using a CPU, etc., with reference to the first coordinate point and the second coordinate point, and the correction magnetic field is This makes it possible to determine automatically, eliminating the need for difficult adjustment work and increasing product value.

[Brief explanation of the drawing]

FIG. 1 is a vector diagram for explaining an embodiment of a disturbance correction method for a vehicle-mounted direction meter according to the present invention.

[Figure 2] Plan view of the orientation sensor section of the vehicle-mounted orientation meter

[Figure 3]
III-III line sectional view in Figure 2

[Figure 4] Diagram showing a voltage signal extraction circuit from the orientation sensor section

[Figure 5] Vector diagram explaining the influence of vehicle magnetization

[Explanation of symbols]

1 Magnetic disc 2-1, 2-2 Hall element 3 X direction correction coil 4 Y direction correction coil

Claims (1)

[Claims] [Claim 1] A magnet that rotates according to the geomagnetic direction, a Hall element that detects the magnetic flux of this magnet,
and a traveling direction detecting means for detecting the traveling direction of the vehicle based on the magnetic flux detected by the Hall element, and a disturbance correction method for a vehicle-mounted compass in which a disturbance magnetic field applied to the magnet is canceled by generating a correction magnetic field in a correction coil. , a test magnetic field is created by supplying a specified current to the correction coil, a coordinate point corresponding to the detected traveling direction at this time is determined as the first coordinate point, and then the vehicle is reversed and the same operation is performed to obtain the second coordinate point.
A disturbance correction method for a vehicle-mounted compass, characterized in that the disturbance magnetic field is determined by using the first coordinate point and the second coordinate point as reference, and the correction magnetic field is determined.