JPS5928241B2 - Houkoukenshiyutsusouchi - Google Patents

Description

[Detailed description of the invention] The present invention relates to a direction detection device for detecting direction.

Generally, a compass that uses a magnetic needle is well known as a device that indicates (detects) direction.

When this compass is used in a vibrating or sloping place, the magnetic needle becomes unstable, making it unsuitable for use in such places.

From the above, there are some that can be used in any location.

As one of these methods, a method using a magnetically sensitive sensor such as a Hall element has been developed.

For example, Feb. 14, 1964 electron
ics.

On page 57 it says “Sol 1d-8t at e
"Compass" has a structure in which a Hall element is sandwiched in a sandwich shape by a mu-metal magnetic flux concentrator, and these are arranged orthogonally. A method has been announced that converts this into a pulse width and extracts it.

Further, in JP-A-5O-72656 "Direction Indicating Device", as shown in FIG. Magnetic flux focusing portions 3a to 4a in the ferromagnetic bodies 3 and 4 are provided orthogonally to each other.
A geomagnetic sensor is constructed by providing magnetic sensing elements 5 and 6 such as Hall elements.

Therefore, each output signal from the magnetic sensing elements 5 and 6 of the geomagnetic sensor is divided into 4 levels, and the combination of these signals produces 16 levels.
I am trying to detect the direction.

Both of the above-mentioned devices are constructed with only two sets of transducers orthogonally crossed, which simplifies the structure.
As a result, the processing of the output signal is complicated and unstable.

Particularly in the latter case, since the level of the output signal varies depending on each element, temperature, etc., the detection direction becomes more difficult as the number of detection directions increases, and there is a risk of malfunction.

This also applies to the former technology to some extent.

Therefore, the present invention provides a direction detection device that digitally detects the orientation (direction), eliminates the drawbacks such as the above-mentioned variations, and attempts to detect as many desired orientations as accurately as possible.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of the magnetic sensor as described above, and FIG. 2 is a diagram symbolically showing this.

FIG. 3 symbolically shows an embodiment of the magnetic sensor according to the present invention, in which one set of magnetic sensors shown in FIG. What is shown by the dotted line is added.

Next, when the magnetic sensor rotates, an output signal is derived with a maximum value when facing north from each magnetic sensing element provided on the axes a□ to d□ indicated by symbols in FIG.

The output signal is derived as a sine wave voltage, but in the present invention, it is illustrated in the form of a triangular wave as shown in FIG.

In this figure, the signal a is the output from the magnetically sensitive element installed on the axis a□ shown in Figure 3, and the other signals are similarly the outputs from the magnetically sensitive element installed on the axis b□, and the signals C indicates the output from the magnetically sensitive element provided on the axis C□, and signal d indicates the output from the magnetically sensitive element provided on the axis d□.

In this case, if the output from each magnetic sensing element is constant, it is easy to determine the intermediate direction by a combination of the level, polarity, etc. of each output, but it may not be accurate due to temperature and other devices. As mentioned above.

Therefore, the present invention detects the direction based on the zero level of the output signals a to d from each magnetic sensing element.

That is, this zero level position (the side door indicated by "0" in FIG. 4) is accurate, and if this is used as a reference, the direction can be detected accurately.

Figure 5 is a block circuit diagram that attempts to detect eight directions based on the output signal from the magnetic sensing element.
RENTIAL AMP) is a zero detection circuit which receives a signal as shown in FIG. 4 and derives an alternating current signal in the embodiment of the present invention when the signal near the zero level is input.

F is a flip-flop, which is set with the above AC signal, reset at an appropriate timing, and outputs a digital signal to terminal A.

−Do. Moreover, the above zero detection circuit D-A□~D
The output of -A4 is led to output terminals A to D.

On the other hand, the output terminals A-D and Ao-Do are connected to the input terminals of the AND gates AG□-AG8, and the respective directions are determined by the outputs from the AND gates AG1-AG8.

For example, if the AND gate AG works opens, it will be in the east (B) direction.
When AG2 is opened, it indicates the west (W) direction, and in this embodiment, detection can be performed in eight directions.

A detailed circuit diagram of the zero detection circuit DA is shown in FIG.

In the figure, a signal from a magnetic sensor is input to the base of the transistor Trl, and an AC reference signal REF is input to the base of the transistor Tr2.

This circuit applies a voltage of 10E to each collector side of the transistors Tr□ and Tr2 through resistors R□ and R2, and applies a voltage of -E to each emitter side through a resistor R3, and further applies a voltage of 10E to each collector side of the transistors Tr□ and Tr2 through a resistor R3. The connection between the collector of r2 and the resistor R2 is outputted to the output terminal A, and is also input to the set input terminal of the flip-flop F.

Note that a reset pulse is input to the reset input terminal of the flip-flop F at an appropriate timing.

In the above, if the magnetic sensor rotates, the fourth
As shown in the figure, a signal is output from each magnetic sensing element, and this signal is input to the zero detection circuit DA.

In this case, as shown in FIG.
-When inputted to the base of the transistor Trl of A□,
From the output side of the circuit D-A1, a signal whose portion corresponding to the zero region of the input voltage a becomes alternating current is led out to the output terminal A and inputted to the flip-flop F□.

At this time, the flip-flop F1 was set at the AC official residence, reset at an appropriate timing, and shifted to the axis a as shown in the figure.
A pulse output waveform corresponding to the near zero of the signal a from the magnetic sensing element provided at the output terminal A is outputted from the output terminal A.

Derived as follows. Similarly, the output terminals B-D and Bo-Do are also output with their phases shifted by 45 degrees.

The signals derived from the respective output terminals A-D and Ao-Do・ are input to the respective AND gates AG□-AG8. is derived and the direction is determined.

For example, if the AND gate AG5 is opened, it can be known that the magnetic sensor is facing north.

In short, the present invention detects the vicinity of the zero level of the output signal of the fall from the magnetic sensing element, and determines the direction based on this in combination with other output signals.

In this embodiment, a set of four sensors consisting of a magneto-sensitive element and a magnetic flux concentrator are installed on the four axes a1 to d1 shown in FIG.
Although a set of magnetic sensors is provided to form a magnetic sensor to perform detection in eight directions, the number of directions will be further increased.

That is, in order to detect the intermediate direction, one set of sensors may be added as shown by the dotted line in FIG. 3, and the same processing as described above may be performed.

Also, in FIG. 4, each output terminal A according to the polarity of the waveform.

It is also relatively easy to determine the intermediate orientation by combining -Do and A-D.

As described above, the direction detection device of the present invention includes a plurality of magnetic sensing means that generate one period of a sine wave by one rotation, as necessary, detects the vicinity of the zero level of the output signal from each sensor, and detects the near zero level of the output signal from each sensor. The direction is determined based on a detection signal near zero level, and since the signal from the sensor is usually accurate near zero, accurate direction detection can be performed.

Furthermore, if a car is equipped with the direction detection device of the present invention, the direction of movement of the car can be accurately detected regardless of the vibrations of the car. If applied, the direction detection will be accurate and therefore more effective.

[Brief explanation of drawings]

Figure 1 is a plan view for explaining the configuration of the magnetic sensor.
FIG. 2 is a diagram symbolically showing FIG. 1. FIG. 3 is a diagram symbolically showing the magnetic sensor of the present invention, FIG. 4 is an output waveform diagram from the magnetic sensor, FIG. 5 is a circuit diagram of the present invention, and FIG. 6 is a zero detection circuit according to the present invention. FIG. 7 is an output waveform diagram derived from each output terminal in FIG. 6. DA: Zero detection circuit.

Claims (1)

[Scope of Claims] 1. A plurality of magnetic sensors that are fixedly arranged radially on an object at a predetermined angle from each other, detect earth's magnetism, and generate a sine wave signal of one period by rotating once; and the plurality of magnetic sensors. a detection means for detecting whether the output of any of the magnetic sensors is near zero, and detecting the output state of the detection means and the output state of a magnetic sensor other than the magnetic sensor whose output is near zero; A direction detection device comprising means for determining the direction in which an object faces.