JPH01172704A - Apparatus for detecting advancing azimuth of vehicle body - Google Patents

Abstract

PURPOSE:To contrive a low cost and improvement in durability and stability in azimuth detection, by computing the azimuth of the direction of a vehicle body with respect to a reference direction in correspondence with the output signals of a magnetism detecting means, which detects the magnetic components of terrestrial magnetism in three-axial directions. CONSTITUTION:A terrestrial magnetism sensor 1 detects the magnetic components of terrestrial magnetism in three-axial directions. The outputs of the sensor 1 are converted in an A/D converter 2. The result is supplied to a microprocessor 3. A display device 5 is connected to the microprocessor 3 through a driving circuit 4. A device 5 has a numerical display 11, which displays an azimuth with respect to the north direction, and an arrow display 12, which displays the running direction with respect to the direction of a target and comprises a light emitting element. A hand switch 6, which indicates the target direction and comprises a non-lock type push button switch, is connected to the processor 3. The outputs in the three-axial direction are supplied from the sensor 1 into the processor. Information, which displays whether the azimuth of the target position can be detected or not is supplied to the microprocessor 3 from the switch 6. Thus the azimuth can be accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a traveling direction detecting device for detecting the longitudinal direction of a vehicle body, that is, the direction of the vehicle body from a reference direction.

BACKGROUND ART A conventional traveling direction detecting device calculates the direction θ from θ-ta based on the X output and y output of a two-axis output type geomagnetic sensor.
A device that calculates by the formula n→(x/y) is known (for example, Japanese Patent Laid-Open No. 57-30668). However, since vehicles such as motorcycles move with rotation in three axes, it is not possible to determine whether or not a two-axis output type geomagnetic sensor is accurately detecting the horizontal component of the geomagnetism. Errors may occur.

Furthermore, since it is necessary to keep the geomagnetic sensor horizontal in order to accurately detect the geomagnetic horizontal component even if the vehicle body is tilted, some vehicles use a gyro to hold the geomagnetic sensor. However, using a gyro increases the cost and has problems with durability and stability.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicle body traveling direction detection device that can accurately detect the direction without using a gyro.

The traveling direction detecting device of the present invention includes a magnetic detection means that is provided on the vehicle body and detects magnetic components in three axial directions of the earth's magnetism, and detects the direction of the vehicle body with respect to a reference direction according to each output signal of the magnetic detection means. The present invention is characterized in that it has a calculation means for calculating.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a motorcycle-mounted navigator equipped with a traveling direction detecting device, which is an embodiment of the present invention. This navigator is provided with a geomagnetic sensor 1 that detects magnetic components in three axial directions of the geomagnetism. The geomagnetic sensor 1 is, for example, a single geomagnetic sensor shown in Japanese Patent Publication No. 62-51777, which is integrally formed and provided in three axial directions. The output of the geomagnetic sensor 1 is converted into a digital signal by an A/D converter 2 and supplied to a microprocessor 3. A display device 5 is connected to the microprocessor 3 via a drive circuit 4. As shown in FIG. 2, the display device 5 includes a numeric display 11 that displays the direction to the north, and an arrow display 1 that includes a light emitting element that displays the direction in which the vehicle should travel relative to the target direction.
It has 2. As shown in FIG. 3, the display device 5 is provided at the front center of the handlebar vibrator 13 of the motorcycle.

Also connected to the microprocessor 3 is a handle switch 6 consisting of a non-locking push button switch for informing the user of the target direction. The handlebar switch 6 is connected to the left handlebar grip 14 of the motorcycle as shown in FIG.
It is fixed to a nearby handle pipe 13 by a support member 15. When the handle switch 6 is operated and turned from off to on, the input level from the handle switch 6 to the microprocessor 3 is inverted from a high level to a low level. Further, a non-locking initialization switch (not shown) is connected to the microprocessor 3. This initialization switch must be operated with the vehicle body in an upright position. Furthermore, an alarm device 17 such as a buzzer is provided in the vehicle, and the alarm device 17 is connected to the microprocessor 3 via a drive circuit 18.

On the other hand, as shown in FIG. 4, the output voltage of the power source (battery) 7 is made constant by a constant voltage circuit 8. The constant voltage is applied to the geomagnetic sensor 1 as a load via a short circuit protection circuit 9.
, D/A converter 2, microprocessor 3, drive circuit 4
, 18, are supplied to the display device 5 and alarm device 17. The short-circuit protection circuit 9 is made of, for example, a high impedance element such as a high resistor.

In such a configuration, the geomagnetic sensor 1 sends outputs in 3-axis directions (X output, Supplied. The geomagnetic sensor 1 is arranged so that the obtained X output represents the geomagnetic component in the left-right direction of the vehicle body, the X output represents the geomagnetic component in the longitudinal direction of the vehicle body, and the 2 outputs represent the geomagnetic component in the direction perpendicular to the longitudinal direction and the left-right direction of the vehicle body. It is mounted on the vehicle body, and when the vehicle body is in an upright state, the X output and the X output indicate the geomagnetic component in the horizontal plane.

When the microprocessor 3 detects the operation of the initialization switch, it starts processing the main routine shown in FIG.
First, an initialization routine (step 21) is executed, and then a direction calculation routine (step 22) for detecting the direction and a heading routine (step 22) for displaying the direction of the destination are executed.
Repeat step 23).

In the initialization routine, first, as shown in FIG.
X output, X output and 2 of geomagnetic sensor 1 with vehicle body upright
Read the output (step 31).

Here, the six values of the read X output, X output, and 2 outputs of the geomagnetic sensor 1 are assumed to be XC+Yt+zt.

After reading each output of the geomagnetic sensor 1, the square value of the total magnetic force Ft at the current location of the vehicle body is calculated from the following equation (step 32).

F42-x62+y72+z62 - (1) By the way, the real horizontal component H of the earth's magnetism at this initialization is expressed as: Here, r is the radius of the earth, M is the magnetic moment of the earth, and ζt is the latitude of the current location of the vehicle on the earth. Also, the vertical component ZL of the current location is lZz 1-Z(,-( 2M/r') sinζt・
- It can be expressed as in (3).

Also, if the inclination angle of the geomagnetic field at the time of initialization is I4, then formula (2)
, from (3), tan 14-12t l/lHj l-2tanζ
t...(4). Furthermore, if the earth's constant is K and -M/r3, then from equations (2) and (3), equation (1) becomes 2 cos 2 for Fi '-.
ζ4 +4 can be expressed as ' sin 2 ζt (5). Therefore, microprocessor 3
After calculating Ft2, calculate K2 from the following equation (step 33).

K2=Ft2/ (cos 2ζ4 +4sin 2
ζt)=Fj 2/ (1+3s1n 2ζt)
-------(6) However, ζ is calculated from equation (4) as ζ4-tan→((1/2) tan Itl-tan
' I (1/2) (lZj l/lHt l)...
...(7) becomes.

FIG. 7 shows the relationship between the total magnetic force F6, the horizontal component Hts, the vertical component Zt, the inclination angle 1, and the orientation θ with respect to magnetic north (N) when the vehicle body is kept upright.

Next, in the azimuth calculation routine, as shown in FIG. 8, first, the X output, the X output, and the magnetic force of the two outputs of the geomagnetic sensor 1 are read (step 41).

Here, each of the read X output, X output, and 2 outputs of the geomagnetic sensor 1 is assumed to be XM, yM+ZM.

After reading each output of the geomagnetic sensor 1, the square value of the total magnetic force FM and the inclination angle IC at the current position of the vehicle body are calculated (step 42.43). The square value of the total magnetic force FM is FM2-XM2+yM2+ZM2-(8). The total magnetic force FM is equal to the total magnetic force F regardless of the rotation or inclination of the vehicle body. The inclination IC is the latitude of the measurement point, Ic = jan'(2tanζ)-tan'
(2sinζ/ 1-5in r) - (9) However, sinζ is 2=FM2/ (1+3sin 2ζ) -, - as in equation (6).
(10) holds, so sln ζ−(1/3)(FM /K −1)−
(11).

After calculating the inclination angle Ic, the microprocessor 3 calculates a vertical component Zc and a horizontal component He at the current position of the vehicle body using the following equations (step 44).

lZc l = l FM 1sin I (------
−(12)l Hc l = l FM 1cos I
c - old °゛(13) Calculated vertical component 1Z
Tolerance value 1Zzl where cl includes the initial value 1Zjl of the vertical component
Step 45) to determine whether it is within ±ΔZ, 1Z
cl<12.1-ΔZ or lZc l>lz4 l+
If ΔZ, the drive circuit 1 is activated to activate the alarm 17.
An alarm command is issued to the terminal 8 (step 46). Upon generation of this alarm, for example, the driver operates the above-mentioned initialization switch to execute the initialization routine and take each initial value again.

On the other hand, if IZzl-Δl≦1Zcl≦lZt l+ΔZ, then the current orientation θd with respect to the N direction is θd −5
in' (XM / l Hc l) ・
...Calculated by (14) step 47),
A numerical display command representing the calculated current orientation θd is issued to the drive circuit 4 (step 48). In response to the numerical display command, the drive circuit 4 causes the numerical display 5 to display the direction θd indicated by the command. When a vehicle such as a motorcycle is traveling straight, the vehicle body tends to be horizontal in the left-right direction, so the orientation θd can be set to a value that ignores the left-right inclination of the vehicle body.

Next, in the heading routine, as shown in FIG. 9, it is first determined whether the absolute value of the difference between the current heading θd and the target location θh is 180° or less (step 51). Direction θh of the target location is determined by handle switch 6.
is determined in step 61, which will be described later.

However, until the handle switch 6 is turned on, the direction θ
h is an initial value. , Icd-θh 1≦180
If the current direction θd is the direction θD, the direction θh of the target location is set the direction θH (step 52). 1θd-θ
If h'l>180', the direction θh of the target location is set to the direction θD
and the current direction θd is set to the direction θH (step 53
). After setting the orientation θD and the orientation θH, it is determined whether or not the orientation θD and the orientation θH are equal (step 54).

If θC-θH, an arrow display stop command is issued to the drive circuit 4 (step 55). The drive circuit 4 stops displaying the arrow display 12 in response to the arrow display stop command.

If θD≠θH, it is determined whether the orientation θD is greater than the orientation θH (step 56). If θD>θH,
A left arrow display command is issued to the drive circuit 4 (step 57). If θC>θH, it is determined whether the orientation θD is smaller than the orientation θH (step 58).

If θD and θH, a right arrow display command is issued to the drive circuit 4 (step 59). The drive circuit 4 causes the arrow indicator 12 to display "-" in response to the left arrow display command, and causes the arrow indicator 12 to display "=" in response to the right arrow display command. Note that step 58 may be omitted. After the display command is issued, it is determined whether or not the handle switch 6 is on (step 60), and when the handle switch 6 is on, the current orientation θd is set as the orientation θh of the target location (step 61). That is, since the handle switch 6 is set to be turned on when the vehicle body is directed toward the target location, the current orientation θd calculated by the azimuth calculation routine when the handle switch 6 is turned on is the orientation θh of the target location. .

For example, as shown in FIG. 10, if the target location T is located at the northeast direction 45@ at the current point P, and the direction of travel is due north (azimuth 0°), the arrow indicator 12 will display "-". " is displayed. Further, if the traveling direction is the B direction of 60 degrees in the northeast, "-" is displayed on the arrow indicator 12.

Effects of the Invention As described above, in the traveling direction detecting device of the present invention, the vehicle body is provided with magnetic detection means for detecting magnetic components in three axial directions of the earth's magnetism, and the direction of the vehicle body is determined according to each output signal of the magnetic detection means. Calculating the orientation with respect to the reference direction is performed. That is, since the horizontal and vertical components of the earth's magnetism can be obtained from each output signal of the magnetic detection means, the orientation can be calculated accurately. Furthermore, since no gyro is required, the configuration is simple, resulting in lower costs, and since there are no moving parts, durability and stability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a motorcycle-mounted navigator equipped with a traveling direction detecting device which is an embodiment of the present invention, FIG. 2 is a diagram showing a display device, and FIG. 3 is a diagram showing a display device and a handlebar switch in a motorcycle. Figure 4 is a block diagram showing the power supply section of the navigator in Figure 1; Figure 5 is a diagram showing the arrangement;
6, 8 and 9 are flowcharts showing the operation of the microprocessor, and FIG. 7 shows the total magnetic force Fts horizontal component H
FIG. 10 is a diagram showing the relationship between ε, vertical component Ztz, inclination It, and azimuth θ with respect to magnetic north (N), and FIG. 10 is a diagram showing the relationship between the target location and the vehicle traveling direction to show the heading motion of the navigator. Explanation of symbols of main parts 1... Geomagnetic sensor 3... Microprocessor 5... Display device 6... Handle switch 9... Short circuit Protection circuit 17... Alarm applicant Honda Motor Co., Ltd.

Claims (1)

[Claims] It is characterized by having magnetic detection means provided on the vehicle body to detect magnetic components in three axial directions of the earth's magnetism, and calculation means for calculating the direction of the vehicle body with respect to a reference direction according to each output signal of the magnetic detection means. Heading direction detection device.