JPH03186702A - Angular displacement detector - Google Patents

Abstract

PURPOSE:To execute the measurement with high accuracy extending over a wide temperature range by determining in advance a reference value for viscosity with regard to a rotational resistance caused by viscosity of a liquid against a floating body and compensating a portion brought to increase/decrease variation by a temperature variation therefrom by a magnetic force action. CONSTITUTION:Photocurrents Ia, Ib generated by a light receiving element 9 are separated in accordance with the centroid position of infrared rays which are made incident on the element 9, and converted to voltages Va, Vb by a current - voltage converting circuit. Subsequently, outputs of Va and Vb and inputted to a differential amplifier and come to the output of Va-Vb, and on the other hand, they are inputted to an addition amplifier, as well and come to the output of Va+Vb. This output of Va+Vb is connected to the inversion input terminal of an OP amplifier 45 through a resistance 46, therefore, an iRED driver circuit varies an energizing current to a light emitting element 8 in accordance with the output of Va+Vb. As a result, the control of a negative feedback is executed so that the output of Va+Vb is made equal to a reference voltage KVC connected to the non-inversion input terminal of the amplifier 45. Accordingly, the difference signal Va-Vb of two outputs of the element 9 can always detect correctly a relative position of an outer cylinder 2 and a floating body 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device that detects angular displacement with respect to absolute space using inertial force, for example, an angular displacement detection device that is suitably used for detecting camera hand movements. It is something.

[Prior Art] Conventionally, this type of angular displacement detection device has been disclosed in Japanese Patent Application No. 1983-1, for example.
As proposed in No. 26375, basic fishing has the configuration detailed below, which is shown in Figures 10 to 10.
To explain using FIG. 12, in these figures, 1
01 is a base on which each component constituting the device is attached; 102 is an outer cylinder serving as a liquid enclosure having a chamber containing a floating body 103 and a liquid 104 inside, and is U-shaped as shown in detail in FIG. A groove portion 102a into which the floating body holder 114 is fitted and fixed is formed inside the groove portion 102a. Reference numeral 103 denotes a floating body having magnetic properties, which is rotatably held by the floating body holder 114 around an axis 103a, and has a mirror 109 on both sides of a pair of sides of the central block, and a slit 110a covering the mirror 109. A mask 110 is attached thereto, and arm portions 103b and 103b extend from the other pair of sides of the central block, respectively.

Further, this floating body 103 is configured to have a rotational balance around the axis 103a and a buoyancy balance within the liquid.

104 is a limb enclosed in the outer cylinder 102.

105 is a light emitting element (IRED) that generates light when energized
The light emitting element holder 107 is attached to the base 1 and fixed thereto. 106 is a light receiving element (PS) consisting of a charge conversion element whose output changes depending on the position of the received light.
D), and is fixed to the base 101 by a photoelectric conversion element holder 108. The light emitting element 105 and the light receiving element 106 constitute optical angular displacement detection means that transmits light via a mirror 109 attached to the surface of the center block of the floating body 103. Note that the light emitting element 105 is mounted on the light emitting element holder 107.
A light guide section 107a is formed to guide light from the mirror of the floating body 103 at the tip of this guide section 107a.
A mask 110 having the same slit 110a as the mask 110 covering the mask 109 is attached. Note that this optical transmission is performed through the outer tube 102, so
The entire outer cylinder 102 or a corresponding portion thereof is provided as a transparent body.

Reference numerals 119 and 120 denote a pair of yokes, which hold the floating body 103 having the above-mentioned magnetic properties at a certain position (the position of the attitude shown in the figure).
One end 119a of these is provided in a pair so as to exert a magnetic field effect for fixing.

120a are provided facing each other and spaced from each other in the diametrical direction of the outer cylinder 102, as shown in the figure. Also these yokes 119.12
A yoke 121 is provided between the other ends of the yoke 1, and an electromagnetic coil 122 is externally fitted and assembled to the yoke 121. With these configurations, yoke 1
19, 120, 121 and the floating body 103, a magnetic circuit is constructed, and the magnetic force generated by the electromagnetic coil 122 applies a magnetic force to the floating body 103.

The floating body 103 described above is held rotatably in the following manner. That is, the central block of the floating body 103 is provided with a rotating shaft 111 penetrating the upper and lower sides as shown in the cross-sectional view of FIG. 11, and pivots 112 having sharp tips pointing outward are press-fitted into the upper and lower ends of the rotary shaft 111, respectively. On the other hand, pivot bearings 113 are provided at the tips of the U-shaped upper and lower arms of the floating body holder 114 so as to face each other inwardly. is maintained.

Reference numeral 115 denotes an upper lid of the outer cylinder, which is sealed and bonded to the outer cylinder 2 by a known technique using silicone adhesive or the like. 11
Reference numeral 6 denotes a rubber gasket, which is sandwiched between the presser plate 117 and the upper lid 115 and fixed with screws or the like.

In the above configuration, the floating body 103 maintains a rotational balance around the axis 1038 and ( It is constructed so that the buoyancy balance within the night body is maintained.

In this configuration, even if the outer cylinder rotates around the rotation axis 103a, the inside of the liquid does not move due to inertia, so the floating body 103 does not rotate, and therefore the outer cylinder 102 and the floating body 103 rotate around the rotation axis 1038. It will rotate relatively. This is the principle of the wooden device that detects relative angular displacements, and these relative angular displacements are detected by the light emitting element 105.
, can be detected by optical detection means using the light receiving element 106.

In reality, a flow occurs inside the sealed liquid due to the influence of the wall surface of the outer cylinder 102, which exerts a force on the floating body 103 and acts as a viscous force, but this effect depends on the distance from the wall surface to the floating body 103, and the viscosity of the liquid. It is possible to make the size as small as possible by taking the following factors into consideration when making a selection.

Angular displacement detection in the apparatus having the above configuration is performed as follows.

First, the light emitted from the light emitting element 105 is transmitted to the light guide section 107.
It passes through a and is irradiated onto the floating body 103, where the mirror 109
The light is reflected by the light receiving element 106. As mentioned above, the leading part 1 (the tip of the floating body 1
Since masks 110, 110 are arranged on the mirror 109 of 03, the light passes through the slits 1lOa, 110a of these masks 110, 110 during the transmission of the above-mentioned light.
As a result, the light becomes substantially parallel light, and an unblurred image is formed on the light receiving element 106.

Outer cylinder 102, light emitting element 105, light receiving element 106
Both are fixed on the base lot and move together, so when a relative angular displacement movement occurs between the outer cylinder 102 and the floating body 103, the light is received by an amount corresponding to the displacement. The slit image on element 106 will move. Therefore, the output of the light receiving element 106, which is a photoelectric conversion element whose output changes depending on the position of the received light, is an output proportional to the positional displacement of the slit image, and the angular displacement of the outer tube 102 can be detected using this output as information. I can do it.

Considering the angular displacement detection device formed with the above configuration, since the floating body 103 is not receiving any external force, the attitude of the floating body 103 cannot be regulated.
As it is, there is no guarantee that the slit image will be located within the measurement range of the light receiving element 106, but for example, by applying a weak magnetic field to the floating body using the electromagnetic coil 122 described above, this magnetic field action will cause the floating body 103 to be placed in the tenth position. A force can be applied as a spring force to fix the device in the steady state position shown in the figure.

The spring force exerted on the floating body by the action of this magnetic field is, in principle, a force that maintains the floating body 103 in a constant attitude with respect to the outer cylinder 102 (that is, moves the floating body 103 as one), so if the spring force is strong, the floating body The cylinder 102 and the floating body 103 move together, causing the problem that the relative angular displacement for the desired angular displacement does not occur, or if the magnetic field action is sufficiently small relative to the inertia of the liquid, the frequency is relatively low. It can also be configured to respond to angular displacement.

[Problems to be Solved by the Invention] By the way, as can be seen from the above explanation, the performance and size of the present device are greatly affected by the liquid sealed therein. Therefore, the restrictions placed on liquids are severe.
Specifically, it is required to use a heptadium that has light transparency, low viscosity, and high specific gravity.

For example, optical transparency is essential for position detection using light using absorption and reception. Furthermore, the viscosity of the liquid theoretically exerts a viscous force in the direction of moving the outer cylinder 102 and the floating body 103 together due to its action with the outer cylinder wall surface, so if this viscosity is large, accuracy will deteriorate. Therefore, using a liquid with low viscosity and low viscous force will improve accuracy.

This is also useful for downsizing the device for the purpose of maintaining the same accuracy. In other words, since the viscosity of the liquid is low, the gap between the wall surface of the outer cylinder 102 and the floating body 103 can be made small, so that the device can be made more compact. Regarding specific gravity, since this device is a detection device that uses inertia, it is natural that the accuracy improves as the inertia increases.On the other hand, in order to maintain the same accuracy, it is necessary to make the device more compact as the specific gravity of the liquid increases. It is easy to understand that this is possible.

The above are the main physical properties required of the 7-night body used in the above-mentioned device, and in reality, liquids with relatively good physical properties that meet these constraints include, for example, fluorine-based inert liquids. can give. However, the viscosity of liquids that satisfy the above-mentioned main physical properties varies greatly depending on the temperature, and many liquids have the property that the viscosity increases exponentially as the temperature decreases. Therefore, if such a liquid is used, the viscosity of the liquid will be low at high temperatures, and the characteristics of the angular displacement detection device will become oscillatory near the resonance frequency, resulting in a large output. As the viscosity increases, the output of the angular displacement detection device decreases on the low frequency side, and the phase lead increases.As a result, it is difficult to obtain high measurement accuracy over a wide temperature range from low to high temperatures. The problem was that it was difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide an angular displacement detection device that solves the problems of the prior art as described above and can realize stable and highly accurate measurement over a wide temperature range.

Another object of the present invention is to provide an angular displacement detecting device of the type in which a liquid is sealed in a body, and to allow greater freedom in selecting the liquid to be used.

[Means and Effects for Solving the Problems] The angular displacement device of the present invention that achieves the above objects is characterized by having a chamber filled with liquid, supported rotatably around a predetermined axis within this chamber,
and a floating body made of a permanent magnet having substantially the same specific gravity as the liquid;
An optical device that detects a relative rotational angle deviation between a magnetic body that is fixedly placed at a fixed position outside the room and exerts a magnetic attraction force between it and the floating body, and a chamber of the floating body that is rotationally displaced from the fixed position. a detection means, a magnetic force generation means provided to selectively apply a magnetic force for rotating the floating body in the forward and reverse directions, a temperature detection means for outputting information on the detected temperature of the body; The magnetic force control means is provided for changing the magnetic force generation and magnetic force strength by the magnetic force generating means in accordance with the temperature-dependent increase/decrease in viscosity of the liquid based on the output of the temperature detecting means.

In the above configuration, the magnetic force control means is controlled to generate magnetic force when a relative rotational angle deviation occurs between the floating body and the chamber, and in particular, the magnetic force control means is controlled to generate a magnetic force when a relative rotational angle deviation occurs between the floating body and the chamber, and in particular, the rotational resistance due to the viscosity of the seven night body with respect to the floating body is determined in advance based on the viscosity standard. A typical example is one in which a value is determined and the increase or decrease due to temperature change is compensated for by magnetic force. As a result, increases and decreases in viscous force due to changes in liquid viscosity caused by temperature changes can be offset by variable magnetic force, allowing high measurement accuracy to be maintained over a wide temperature range.

[Example] The present invention will be described below based on embodiments shown in the drawings.

1 to 4 show a first embodiment of the present invention,
In these figures, 1 is a base plate on which each component constituting the device is attached, and 2 is an outer cylinder having a chamber in which a floating body 3 and a liquid 4 are sealed.

3 is a floating body, which is held by a floating body holder 5 so as to be rotatable around I+b3b. And this floating body 3, protrusion 3
A slit-like reflective surface is formed on a. The floating body 3 is made of a material made of a permanent magnet, and is magnetized in the direction of the axis 3b. Note that this floating body 3 has a shaft 3
The structure is such that the rotational balance around b and the floating body are balanced.

The floating body 3 mentioned above is made of a permanent magnetic material having the same specific gravity as the liquid 4, and can be manufactured, for example, as follows.

In other words, if we use the above-mentioned fluorine-based inert 7-night body as the liquid, we can adjust the content by adding fine powder of a permanent magnet material (such as ferrite) as a filler to a plastic material as a base. For example, volume content 8
%) to make the specific gravity approximately the same as the liquid's specific gravity of 1.8.

After the floating body 3 is molded from such a material (or at the same time) by magnetizing it in the direction of the axis 3b, the floating body 3 can be made into a permanent magnet.

Reference numeral 5 denotes the above-mentioned floating body holder, which is fixed to the outer cylinder 2 while holding the floating body 3 via a pivot bearing 13, which will be described later. Reference numeral 6 denotes a U-shaped yoke attached to the main plate 1 as shown in the figure, and forms a closed magnetic path together with the floating body 3.

Reference numeral 7 denotes a winding coil, which is arranged between the floating body 3 and the yoke 6 and fixed to the outer cylinder 2. Reference numeral 8 denotes a light emitting element (IRED) that generates light when energized, and is attached to the base plate 1. Reference numeral 9 denotes a light receiving element (PSO) whose output changes depending on the position of the received light, and is attached to the base plate 1. These light emitting elements 8 and light receiving elements 9
constitutes an optical angular displacement detection means that transmits light via the reflecting surface 3a of the floating body 3.

Note that 10 is a mask placed in front of the light emitting element 8, and has a slit hole 10a through which light passes. Further, reference numeral 11 denotes a stopper member attached to the outer cylinder 2, and is provided to determine a rotation limit position so that the floating body 3 does not rotate outside a predetermined range.

The floating body 3 described above is held rotatably in the following manner. That is, as shown in FIG. 2, which is a cross-sectional view taken from FIG. 1 to FIG. Pivot bearings 13 are provided at the tips facing each other inwardly, and the sharp tips of the pivots 12 fit into the recesses of the pivot bearings 13 to hold the floating body.

Reference numeral 14 denotes an upper lid of the outer cylinder, which is sealed and bonded to seal the liquid in the outer cylinder 2 by a known technique using silicone adhesive or the like.

The floating body 3 is provided in a symmetrical shape around the rotation axis 3b so that no rotational moment is generated due to the influence of gravity in any posture, and no eccentric load is applied to the pivot axis. Constructed of material with the same specific gravity as 4. Here, the above-mentioned absence of rotational moment etc. is a hypothetical condition, but in reality, it is sufficient to configure it within the allowable range in terms of measurement accuracy, and the shape error only acts as an unbalance due to the specific gravity difference, so in reality It is easy to understand that it is possible to construct a device that is sufficiently small in terms of the friction and has an extremely good S/N ratio of friction to inertia.

To explain the effect of the above configuration, if the outer cylinder 2 is now rotated around the rotation axis 38, the liquid 4 inside is stationary with respect to absolute space due to inertia, so the floating body 3 in a floating state does not rotate. . Therefore, the outer cylinder 2 and the floating body 3 rotate relative to each other around the rotation axis 3a. These relative angular displacements are detected by optical detection means using the light emitting element 8 and light receiving element 9.

That is, the light emitted from the light emitting element 8 is transmitted through the mask 10.
The light passes through the slit hole 10a and is irradiated onto the floating body 3, where it is reflected by the slit-shaped reflective surface of the protrusion 3a and reaches the light receiving element 9. In addition, when transmitting the light mentioned above, the light passes through the slit hole 1.
0a and the slit-shaped reflective surface, the light becomes substantially parallel light, and an unblurred image is formed on the light receiving element 9.

Since the outer cylinder 2, the light emitting element 8, and the light receiving element 9 are all fixed to the base plate 1 and move together,
When a relative angular displacement movement occurs between the outer cylinder 2 and the floating body 3 as described above, the slit image on the light receiving element 9 moves by an amount corresponding to the displacement. Therefore, the output of the light receiving element 8, which is a photoelectric conversion element whose output changes depending on the position of the received light, is an output proportional to the positional displacement of the slit image, and the angular displacement of the outer cylinder 2 is detected using this output as information. be able to.

FIG. 4 is a sectional view taken along the line B--B in FIG. As shown in the figure, the floating body 3 is magnetized in the direction of the axis 3a, and in this embodiment, the upper side is magnetized with Na and the lower side is magnetized with S pole. Ni
The lines of magnetic force coming out of the U-shaped yoke pass through the U-shaped yoke and enter the S pole, forming a closed magnetic path.If a current is passed through the winding coil 7 placed in this magnetic path from the back side of the page to the front side as shown in the figure, According to Fleming's left-hand rule, the winding coil 7 receives a force in the direction of arrow f. However, since the winding coil 7 is provided in a fixed relationship with the outer cylinder 2, it cannot move.
The floating body 3 is driven by the reaction force in the direction of arrow F. It goes without saying that this force is proportional to the current applied to the winding coil 7, and that the force acts in the opposite direction if the current is passed in the opposite direction to that described above. That is, in the configuration of this embodiment, it is possible to freely drive the floating body in both forward and reverse directions by the action of 6u force.

In addition, in the above configuration, considering the closed 6n air circuit created by the floating body 3 and the yoke 6, the floating body itself, which was considered to have extremely high magnetic permeability in the conventional example, forms a permanent magnet in this example. Therefore, the magnetic resistance of the closed magnetic circuit is significantly reduced. Therefore, in the past, a large current had to be passed through the electromagnetic coil in order to overcome the magnetic resistance and form a magnetic field. Since the structure is such that the floating body is driven by the floating body, the electric-magnetic conversion efficiency is greatly improved, and there is an advantage that an energy-saving device can be constructed.

Next, the overall circuit for controlling the present invention will be explained with reference to FIG.

The circuit portion in FIG. 5A shows a position detection circuit for the above-mentioned optical detection means for detecting the relative rotated position of the floating body 3 with respect to the outer cylinder 2. That is, the basic configuration is such that infrared light emitted from the light emitting element 8 is reflected by the floating body 3, and is received by the light receiving element 9 for position detection to detect angular displacement.

To explain this in detail below, first, the photocurrents 1a and lb generated in the light receiving element 9 are divided according to the position of the center of gravity of the infrared light incident on the light receiving element 9, as is known.
A current-voltage conversion circuit composed of a P amplifier 30, a resistor 31, and a capacitor 32, an OP amplifier 33, and a resistor 34
, and is converted into voltages Va and Vb by a current-voltage conversion circuit composed of a capacitor 35. Next, the outputs of Va and Vb are inputted to a differential amplifier consisting of an OP amplifier 36 and resistors 37, 38, 39, 40, and outputted as Va-Vb. The signal is also input to the summing amplifier composed of 43 and 44, resulting in an output of Va+Vb. Since the output of Va+Vb is connected to the inverting input terminal of the OP amplifier 45 via the resistor 46, a constant current type circuit consisting of the OP amplifier 45, the feedback resistor 47, the current value detection resistor 49, and the transistor 50 is connected. The 1RED driver circuit varies the current flowing to the light emitting element 8 according to the output of Va + Vb, and as a result, Va
Negative feedback control is performed so that the output of +Vb becomes equal to the reference voltage KVC connected to the non-inverting input terminal of the OP amplifier 45.

The capacitor 48 is a phase compensation capacitor to prevent this feedback system from oscillating, and in combination with the resistor 47 determines the overall band.

As described above, in this example, the photocurrent generated in the light receiving element 9 is always kept constant, so the difference signal Va-Vb between the two outputs of the light receiving element 9 is determined by changes in temperature etc. and variations in the element. The relative position of the outer cylinder 2 and the floating body 3 can always be detected correctly without being affected by such factors.

Next, the part of the circuit shown in FIG. 5B will be explained. This constitutes an arithmetic circuit for determining the parameters of the sensor. That is, the output Va-Vb of the OP amplifier 36
is input to a differentiating circuit composed of a capacitor 59, a resistor 60, and an OP amplifier 58, where the relative speed output from the sensor is obtained. This output is connected to the inverting input terminal of the OP amplifier 55 via the gain setting resistor 57. Note that a feedback resistor 56 is connected to the OP amplifier 55, and by configuring this resistor with a temperature-sensitive resistor with a positive temperature coefficient, the circuit gain is increased when the temperature rises, and is decreased when the temperature decreases. I have to.

Explaining the circuit portion of FIG. 5C, this constitutes a driver circuit portion for actually driving the winding coil 7.

That is, the OP amplifier 51, the transistors 52, 53,
A push-pull type constant current circuit is configured by the current detection resistor 54, and current can flow in either the X or Y directions indicated by the arrows in FIG. Therefore OP
OP amplifier 5 applied to the non-inverting blade terminal of amplifier 51
A current proportional to the output voltage of 5 is applied to the winding coil 7.

According to the circuit configuration as described above, by supplying a current proportional to the differential value of the relative position signal Va-Vb between the outer cylinder 2 and the floating body 3 to the winding coil 7, the floating body 3 and the yoke 6 are connected as described above. A force based on Fleming's left-hand rule is generated in the closed magnetic circuit composed of will occur.

Next, the characteristics of the sensor of the present invention will be explained using the frequency transfer characteristics shown in FIG. The angular displacement signal I (S) as an input indicates the displacement of the outer cylinder 2 with respect to the absolute space, and the output angular displacement O (S) detected by the sensor of the present invention is the absolute displacement of the floating body 3. 9 detected from the relative relationship between displacement R(S) with respect to space and manual angular displacement r(S).

0(S) =I(S) −R(S)
...It is expressed by the formula (1).

Also, this output angular displacement is the relative angular displacement between the outer cylinder 2 and the floating body 3, and as explained in the conventional example, the liquid sealed in the outer cylinder 2 causes a viscosity proportional to the relative velocity between the outer cylinder 2 and the floating body 3. force η
SO(S) occurs. On the other hand, if the width of the yoke 6 is infinitely wide in the moving direction of the floating body 3, the winding coil 7
No spring force should be generated due to magnetic force when no current is applied to the yoke, but in reality the width of the yoke is finite, so as explained in the conventional example, although the force is weak, the spring force KO ( S) also works. Furthermore, in this embodiment, a new viscous force can be applied by applying a current proportional to the differential value of the relative displacement between the outer cylinder 2 and the floating body 3 to the winding coil 7 to generate force using the method described above. can. Here, the viscous force 1uSO(S) due to coil energization is the original viscous force ηSO
(S) acts in the same direction, and by varying the gain of coil energization, it is possible to generate any viscous force.

Considering the above force as a force acting on the floating body 3, it can be expressed by an equation that uses the moment of inertia J of the liquid in the outer cylinder 3 to express the angular displacement R(S) of the floating body with respect to the pure body space.

Using equations (1) and (2), the transfer characteristic of the present invention is expressed as follows.

Equation (3) shows the characteristics of a second-order bypass filter, and if the viscous force is electrically controlled, even if the viscosity of the liquid changes depending on the temperature, the gain of the coil energization can be varied according to the temperature. By doing so, you can always keep the frequency characteristics constant.

[Example 2] FIG. 7 shows a second example of the present invention.
Since the circuit portions A and C in the figure are completely the same as those in FIG. 5, their explanation will be omitted.

The circuit part B is an arithmetic circuit for determining parameters as a sensor, and the output Va-Vb of the OP amplifier 36
is input to the non-inverting input terminal of the OP amplifier 58 via the capacitor 59. Here, the circuit composed of the OP amplifier 58, the capacitor 59, and the resistor 60 has a capacitance value C
For three resistance values R wave numbers, it operates as a differentiating circuit.

Next, the output of the OP amplifier 58 is connected to the inverting input terminal of the OP amplifier 61 via the MO5 resistor 63 for gain setting, and since the feedback resistor 64 is connected to the OP amplifier 61, an inverting amplifier is connected. configured.

The output of the OP amplifier 61 is input to the driver circuit section C, and as described in the first embodiment, the driver circuit section C supplies a current proportional to the output of the OP amplifier 61 to the winding coil 7. Therefore, in this embodiment, the outer cylinder 2
and the differential value of the relative displacement of the floating body 3, that is, a force proportional to the relative velocity is generated.

On the other hand, the output of the temperature proportional voltage generation circuit 62 has a positive temperature coefficient such that the output increases as the quality increases and decreases as the temperature decreases.
is added to the gate input. Since the ON resistance of the MO5 resistor 63 changes almost logarithmically depending on the voltage applied to its gate, the coil viscous force ηuso (S) changes almost logarithmically in response to temperature changes, as described in the first embodiment. Its power can be varied.

Therefore, even when the viscous force of the liquid increases significantly at low temperatures, by applying the viscous force by energizing the coil, the overall viscous force can be kept almost constant regardless of the temperature.

[Embodiment 3] FIG. 8 shows a third embodiment of the present invention, and shows an example in which the viscous force caused by coil energization is digitally varied in accordance with the temperature. FIG. 9 shows the flowchart. Here, regarding the detection circuit part A and the driver circuit part C, the first and second
This is similar to the embodiment.

In the circuit of this embodiment, the circuit section B is a section that digitally sets the gain, and is a circuit section A/B that converts the displacement output Va-Vb from the sensor into digital data.
D converter 70. C that performs overall calculations and state detection
Consists of a PU (central processing circuit) 71, a D/A converter 72 that outputs analog data to actually drive the driver based on data from the CPU, and a temperature-sensitive resistor 74 and a resistor 73 for detecting temperature. has been done.

Next, the operation of this embodiment will be explained using the flowchart shown in FIG.

First, in flow 200, a coefficient for digitally differentiating the output Va-Vb of the displacement sensor is set, where the value of T represents the period of sampling time for performing A/D conversion, and C is Capacitance value of capacitor 59 in Fig. 5, R
represents the resistance value of the resistor 60. In flow 201, the value of register W1 used for calculation is reset to O. Next, in flow 202, the ^/D converter 70 starts A/D conversion of the relative displacement output Va-Vb between the outer cylinder 2 and the floating body 3 and the voltage level using the temperature-sensitive resistor in response to an A/D control signal from the CPU 71. Next, in flow 203, it is determined whether the A/D conversion has been completed, and if the A/D conversion has been completed, the A/D result of the displacement sensor is first transferred to CPU register A in flow 204, and Next, in flow 205, the output of temperature data is transferred to CPU register B. In flow 206, a differential operation on the time axis accompanying the known SZ transformation is performed, and the result is set in register A. On the other hand, in flow 207, a predetermined value is transferred from memory data 220 to register K depending on the value of register B in which temperature data is stored, and gain data corresponding to the temperature data is set. Next, in flow 208, the value obtained by multiplying the value of register A by the value of K is set in register A as data to be transferred to the D/A converter, and in flow 209, the value of register A is set to D/A converter 7.
Transfer to 2. Next, in flow 210, the D converter starts operating according to the control signal 7 from the CPU 71,
After detecting completion of the D/A conversion in flow 211, the process returns to flow 202 and repeats the above operations.

Since the output of the D/A converter 72 is connected to the human power section of the driver circuit C, a current proportional to the output of the D/A converter is applied to the winding coil 7.

Therefore, in this embodiment, if data for setting the gain of coil energization with respect to temperature is stored in advance, even if the viscosity of the liquid changes, the overall frequency characteristics can be kept constant by the viscous force caused by coil energization.

[Effects of the Invention] As explained above, is the angular displacement detection device of the present invention included in a sensor? Even if the viscosity of the Fi body changes greatly depending on the temperature, the characteristics can be kept constant at all times by varying the viscous force caused by energizing the coil in accordance with the temperature.

Therefore, even when using a heptad whose viscous properties are highly temperature dependent, there is an effect that highly accurate angular displacement measurement can be performed over a wide temperature range.

In addition, there is usually no need to energize the coil, and only a small amount of energizing power is required to exert a magnetic effect on the liquid, resulting in the advantage that an energy-saving and compact device can be constructed.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing the configuration of mechanical components of an embodiment of the angular displacement detection device according to the present invention, FIG. 2 is a sectional view taken along the line A-A in FIG. 1, and FIG. Cross-sectional view taken along line B-B in Figure 1.
FIG. 3 is a perspective view of the same part, and FIG. 4 is a diagram for explaining the state in which a rotational force acts on the floating body due to the action of magnetic force. FIG. 5 is an overall diagram of a control circuit for controlling the first embodiment, and FIG. 6 is a frequency transfer characteristic diagram showing the characteristics of the device of the first embodiment as a sensor. FIG. 7 is an overall diagram of a control circuit for controlling a second embodiment of the present invention. FIG. 8 is an overall diagram of a control circuit for controlling a third embodiment of the present invention, and FIG. 9 is a flowchart illustrating the control operation by the circuit. 10 to 12 are diagrams for explaining a conventional example, in which FIG. 10 is a schematic plan view of the angle detection device, FIG. 11 is a vertical cross-sectional view of FIG. 10, and FIG. 12 is an exploded view of parts. It is. 1: Main plate 2: Outer cylinder 3/floating body 3a: Yoshitaka 3b: Shaft 4: Liquid 5: Floating body support 6: Yoke 7: Winding coil 8: Light receiving element 9: Light receiving element 10 Nisrit 14, upper lid 4th person Figure Δ Figure Figure Figure 9 Figure 10 Figure A 1 Figure 190 IQ51) Scale 5° Figure 2

Claims (1)

[Scope of Claims] 1. A chamber containing a liquid, a floating body rotatably supported around a fixed axis in the chamber and made of a permanent magnet having substantially the same specific gravity as the liquid, and a fixed position outside the chamber. an optical detection means for detecting a relative rotational angle deviation between a magnetic body that is fixedly disposed on and exerts a magnetic attraction force between the floating body and a chamber of the floating body that is rotationally displaced from the fixed position; a magnetic force generating means provided to selectively apply a magnetic force to rotate the liquid in the forward and reverse directions; a temperature detecting means for outputting information on the detected temperature of the liquid; An angular displacement detection device characterized in that it is provided with a magnetic force control means for changing the magnetic force generation and magnetic force strength by the magnetic force generating means in accordance with the temperature-dependent increase and decrease of viscosity. 2. The angular displacement detection device according to claim 1, wherein the magnetic force control means generates magnetic force when a relative rotational angle deviation between the floating body and the chamber occurs. 3. In claim 2, the magnetic force control means is such that when the rotational resistance of the floating body due to the viscosity of the liquid increases or decreases from a predetermined reference value of viscosity due to temperature change, the magnetic force control means compensates for the change by magnetic force action. An angular displacement detection device characterized by: