JPH02181605A - Inclination detector - Google Patents

Abstract

PURPOSE:To reduce the size of a detection part and to offer the inclination detecting device which is easy to handle by charging magnetic fluid in an air core where an exciting coil and a detection coil are situated and utilizing variation in the mutual inductance between both the coils due to the flow of the magnetic fluid. CONSTITUTION:The exciting coil 2 is provided above the ring-shaped empty core 1, the detection coil 3 is wound below so that its right and left numbers of turns are equal, and the magnetic fluid 4 is charged nearby the detection coil 3 on the air core 1. The air core 1 is held at the fixation part 5a of a holding part 5 and when the bottom surface 5c of the base part 5b of the holding part 5 is mounted on an uninclinded surface, the magnetic liquid 4 is all made equal in relative position with the left and right detection coils 3a and 3b. When the bottom surface 5c is mounted on a slanting surface so as to measure the degree of the inclination, the magnetic fluid 4 flows so as to hold the levelness of its surface and shift in relative position with the left and right detection coils 3a and 3b. The inclination can be detected from variation in the mutual inductance between the detection coils 3a and 3b.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a tilt detection device that detects tilt from a horizontal plane.

[Prior art and its problems] Most conventional tilt detection devices use a pendulum, and the lower surface of the detection case, which holds the pendulum suspended, is installed along the slope to be measured. It was common to electrically detect the rotation angle of the pendulum when the pendulum was rotated, and then obtain the inclination of the inclined plane.

However, since this type of device uses a pendulum, the detection section is large and it is not easy to handle.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide an inclination detection device whose detection section can be made smaller and which is easy to handle.

[Summary of the Invention] In order to achieve the above object, the present invention includes a magnetic fluid that flows according to the inclination of the two air cores, which is enclosed in an air core around which an excitation coil and a detection coil are wound. The gist is that the change in mutual inductance between the excitation coil and detection coil due to fluid flow is utilized.

[Example] The present invention will be specifically described below based on an example shown in one drawing.

Figure 1 shows the detection section of this embodiment. Above the air core l, which is a ring-shaped space made of a non-magnetic material such as glass or resin, an excitation coil 2 is wound with an equal number of turns on the left and right sides with respect to the vertical diameter. Further, below the air core 1, a detection coil 3 is wound with the number of turns equal to the left and right sides with respect to the above-mentioned vertical diameter. The winding direction is opposite.

Further, a magnetic fluid 4 is sealed in the vicinity of the detection coil 3 inside the tube of the air core 1.

The holding part 5 that holds the air core 1 consists of a flat plate-shaped fixing part 5a and a stand part 5b, the fixing part 5a is fixed perpendicularly to the stand part 5b, and the air core 1 is fixed to the fixing part 5a. There is. Therefore, the above-mentioned platform 5b is placed on the inclined surface whose degree of inclination is to be measured.
When placed so that the bottom surface 5c of the magnetic fluid 4 is placed in contact with the bottom surface 5c, the magnetic fluid 4 flows inside the tube of the air core 1 to keep the surface horizontal.
That will happen.

FIG. 2 shows the circuit configuration of this embodiment. The detection circuit 8 is the electric circuit of the detection section explained in FIG. The coil 3 is inductively coupled. Further, one end of the excitation coil 2 is connected to one end of one coil 9J of the variable mutual inductor 9, and the coil end of the right detection coil 3b is connected to one end of the other coil 9b. An alternating voltage signal of a predetermined frequency is applied from the oscillator lO to the series circuit consisting of the excitation coil 2 and one coil 9a, and an output signal from the series circuit consisting of the detection coil 3 and the other coil 9b is transmitted to the lock-in amplifier 11. The signal is amplified and sent out.

The operation of this embodiment configured as described above will now be explained.

FIG. 3(a) shows the relationship among the air core 1, excitation coil 2, detection coil 3, and magnetic fluid 4 when the detection section shown in FIG. 1 is placed on a non-inclined surface. In this case, the left side detection coil 3a and the right side detection coil 3b of the magnetic fluid 4
The relative positions will be exactly the same. Therefore, even if an alternating excitation current is caused to flow through the excitation coil 2 by a signal from the oscillator 10 and an alternating magnetomotive force is generated, no output is generated between both ends of the detection coil 3, that is, the magnetic flux generated by the above magnetomotive force. Most of them use an air core, so they take the magnetic flux φ0 path, but some of them take the magnetic flux φ1, φ♂,
Take the route φb. Furthermore, since the relative positions of the magnetic fluid 4 with respect to the left side detection coil 3a and the right side detection coil 3b are equal, the number of magnetic fluxes passing through the paths φa and φb is equal, and φ
The magnetic flux passing through path 1 interlinks with both the left side detection coil 3a and the right side detection coil 3b. Therefore, the number of magnetic flux linkages of the left side detection coil 3a and the right side detection coil 3b is equal, and since the winding directions of both coils are different as described above, the induced electromotive force generated in both coils cancels each other, will produce no output.

On the other hand, FIG. 3(b) shows the relationship between the air core 1, the excitation coil 2, the detection coil 3, and the magnetic fluid 4 when the detection unit is placed on an inclined surface. In this case, the magnetic fluid 4 flows to keep its surface level, changing its relative position with respect to the left side detection coil 3a and the right side detection section 3b, as shown in the figure. In this case, the path of the magnetic flux φa has a longer path through the magnetic fluid than the path of the magnetic flux φb, and the magnetic resistance is lower, and the number of magnetic fluxes passing through the path of the magnetic flux φ1 is greater than the path of the magnetic flux φb. It increases more than the number of magnetic flux passing through. Therefore, the number of magnetic flux linkages of the left side detection coil 3a becomes greater than the number of magnetic flux linkages of the right side detection coil 3b, and the induced electromotive force of the left side detection coil 3a becomes larger than the induced electromotive force of the right side detection coil 3b. An output is generated by subtracting the induced electromotive force of the right side detection coil 3b from the induced electromotive force of the left side detection coil 3a. In this case, the movement due to the flow of the magnetic fluid 4 increases depending on the degree of inclination of the surface to be measured, so the magnetic flux φ
The difference in the number of magnetic fluxes passing through the paths a and φb also corresponds to the degree of inclination, and as a result, the output from the detection coil 3 also corresponds to the degree of inclination.

The output of the detection coil 3 obtained as described above is combined with the constant level voltage signal of the other coil 9b of the variable mutual inductor 9, and sent to the lock-in amplifier 11 where it is amplified and produces a slope detection signal. Sent as .

Note that when measuring a surface that is inclined in the opposite direction to the above case, the relative positional relationship between the magnetic fluid 4 and the left side detection coil 3a and right side detection coil 3b is reversed, so the output of the detection coil 3 is as follows. Although the phase is shifted by π from the case described above, this means that the tilt direction can also be detected.

As described above, since this embodiment does not use a pendulum, the detection unit can be made smaller and can be used for posture control of robots, etc.

Note that this invention is not limited to the above embodiments, and can be modified and applied in various ways without departing from the scope of the invention. For example, in this embodiment, the air core is ring-shaped.
It goes without saying that the shape is not limited to this, but may be a shape that can be arranged symmetrically with respect to a vertical line, such as a rectangular shape or an elliptical shape as shown in FIG.

[Effects of the Invention] As described in detail above, the present invention encloses a magnetic fluid that flows according to the inclination of the air core in an air core around which an excitation coil and a detection coil are wound. Since it relates to a tilt detection device that utilizes changes in mutual inductance between an excitation coil and a detection coil due to flow, the detection section can be made smaller and, by extension, the tilt detection device is easy to handle. It is possible to provide the following.

. . . Detector circuit, 9 . . . Variable mutual inductor, 1
0...Oscillator, 11...Lock-in up.

Claims (1)

[Scope of Claims] An air core having a shape symmetrical with respect to a vertical line; an excitation coil having an equal number of turns wound on the left and right sides near the line of symmetry of the air core; a detection coil wound with an equal number of turns and with different winding directions on the left and right sides of the line of symmetry; a magnetic fluid sealed so as to be able to flow on the detection coil side in the air core; a variable mutual inductor that forms a Hartshorn bridge together with the excitation coil and the detection coil, and an oscillator for inputting the Hartshorn bridge; A tilt detection device comprising: a lock-in amplifier that amplifies the output of the Hartshorn bridge.