JPS62106312A - Torque equilibrium apparatus for measuring angle of inclination - Google Patents

Abstract

PURPOSE:To relieve the impact from the outside, by providing a proportional area having left and right limit points as base points inclusive of left and right ON/OFF boundary areas in light transmission-reception converting characteristics to the variable gap between the surfaces of left and right elements and the reflective surfaces respectively opposed thereto to set the same as the operation area of a feedback current. CONSTITUTION:The max. value of the variable gap between both element surfaces S1, S2 and opposed reflective surfaces is 1mm or less and, eve if there is ON/OFF in the forwardly directing loop Gd in a torque equilibrium block diagram, said loop Gd is regardless of the accuracy of torque equilibrium if a gain is large and this accuracy is entirely determined by a rearwardly directed loop Gf. Actually, in a torque equilibrium angle-of-inclination measuring apparatus using this ON/OFF boundary area, accuracy of + or -1 deg. and an angle of + or -25 deg. are shown at the max. angle of + or -20 deg.. Further, even when impact is applied to the apparatus from the outside, there is no possibility such that a pointer reflective surface is damaged by the attraction or collision with respect to a fixed element surface at all and rather, action relieving impact force is provided. Therefore, it is unnecessary to apply a special protective means for preventing impact to the main body of the apparatus.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is suitable for use in static high-precision tilt measurement such as general surveying and precision measurement of crustal deformation, and dynamic tilt measurement of vehicles, ships, robots, etc. This invention relates to a torque-balanced inclination angle measuring device.

[Conventional technology]

Conventionally, it was proposed based on the invention of Takao Yamaguchi, one of the inventors of the present invention, to configure an electronic inclinometer that can be used for both analog and digital use with a zero center current ammeter type heavy torque measuring device. (Special Publication No. 34-3145 “
(See “Torque Measuring Device”).

Furthermore, a practical version based on this was published as an analog electromagnetic gravimeter by the same inventor in 1966, Journal of the Japan Society of Precision Machinery, Vol. 28, No. 12, page 711. As shown in Fig. 10, the movable part of the meter is pendulum-shaped, and two pickup coils t and t' are fixed facing each other on both sides of aluminum foil attached to the pendulum-shaped pointer. Each corresponds to two sides in series with the high frequency power source of the high frequency bridge circuit. In this bridge configuration, the difference between the inductances of the coil and t' becomes the bridge output, which is fed back to the moving coil of the instrument via an amplifier. Therefore, the gravitational torque applied to the instrument moving part is automatically balanced, and the output value of the bridge indicates the gravitational component force value.

FIG. 11 is a block diagram showing the operation of the gravimeter.

In the same figure, T1 is the gravitational force torque, Tf is the current torque that is negatively fed back to the moving coil, and ε is both torque Tl and Tf.
, G is the transfer function of the detection section consisting of the big angle 7°t and t', G1 is the gain of the amplifier circuit, Eo is the output voltage, G
f indicates the feedback circuit gain.

FIG. 12 shows the characteristics of the detecting section, and as the gap (distance) between Big Ag or t' and each of the opposing pointer aluminum foils increases, the inductance value increases almost proportionally.

In FIG. 12, the following relationship holds true.

Here, GdG,=G, ・・・・・・・・・
...(2) as equation (1) where G? 〉1 ・・・・・・・・・・・・
・If (3) then it becomes.

That is, if the gain of the forward loop transfer function GT is sufficiently large, the output voltage E0 is proportional to the gravitational torque Tl.

In order to improve the practicality of the above-mentioned inductance-type torque-balanced inclinometer, a model in which the pickup section was replaced with a DC power supply type interrupter photoelectric converter was proposed in the patent application filed in 1983-
No. 193294 ``Inertial force dynamic torque measuring device for rotating body'' (inventor: Takao Yamaguchi). This is shown in FIG. In the figure, U is a zero-center DC ammeter with an unbalanced weight m, d is a detection section having a normal interrupter photoelectric converter G and G2, a is an amplification section, and f is a feedback circuit. The block diagram of FIG. 11, which shows the operation of the inductance high frequency bridge type, can be used as is to explain the operation. However, the characteristics of the distance-to-emission/reception-light conversion value of the interrupter photoelectric converter are completely different from the characteristics of the distance-to-inductance conversion value of the inductance type converter.

As shown in FIG. 9(a), the interrupter photoelectric converter consists of a converter body having a light emitting/receiving element surface S and a reflecting surface F facing the element surface S. The main body includes a light emitting diode D and a light receiving transistor PTr. The light emitted from the light emitting diode D is emitted from all eight surfaces, and the reflected light from the F surface is received again by the eight photodetector transistors PTr. In this case, the characteristics of the distance between the 8th plane and the F plane versus the emitted/received light conversion value are as follows:
The result is as shown in FIG. 9 (b). That is, the section from the light emitting/receiving cutoff position at a distance of 0 where the 8th surface and the F surface are in contact and the converted value is 0 to the specific limit point M at a distance that shows the steady converted value is as follows.
On the other hand, the conversion value increases dramatically as the distance increases.
This is an off-boundary area (hereinafter sometimes abbreviated as "boundary area"). When the limit point M is exceeded, a proportional region is reached in which the steady-state conversion value gradually decreases as the distance increases.

The interrupter photoelectric converter shown in FIG. 9(a) is a general type (G type), and the figure ←) shows an example of its conversion value characteristics. In this example, the boundary area is in the range of 0 to 1, and the limit point M of υ and Im, up to about 95 m, is used as a proportional area for measurements in the general industrial field. Therefore, two such interrupter photoelectric converters are arranged symmetrically,
Pixel element surfaces S1 and S2 and their respective opposing reflective surfaces F, ,
If the maximum value of the variable gap (see Figure 1) between F2 and F2 is set to, for example, 6 ms (that is, the maximum value of both variable gaps is at the center position, D3m to the left and right), the distance versus output of each interrupter photoelectric converter is The characteristic curve of the light reception conversion value has a symmetrical shape as shown in FIG. 7(a). If this is redrawn as a differential characteristic of distance vs. difference output, it becomes as shown in the same figure (b). In this case, the left G scale (meaning the case of a G type converter) is used as the output scale in the latter case.

Furthermore, if the distance versus inductance and differential output characteristics of the high-frequency bridge type shown in FIG. 10 are obtained in the same manner, they will be as shown in FIG. 13 0) and Naka).

[Problems that the invention attempts to solve]

Generally, when measuring using the torque balance method, the first
It is conventional wisdom to use a proportional range for the characteristics of the detection section shown in Figure 1 (block diagram) so that it can be used as a displacement meter for general industry. Therefore, when using the interrupter photoelectric converter shown in Fig. 8 in place of the inductance converter shown in Fig. 10, it is a matter of course that the left and right on/off boundary areas are provided in the gap between the left and right element surfaces and the reflecting surface. Including, the limit point of positive and negative outputs centered on the equilibrium point of left and right outputs (Ml.

Set the proportional range between M2) as the feedback operating range,
Within this range, the output difference current can be negatively fed back. Transfer function G of the detection unit in FIG. 11 in this case.

shows the same tendency as the high frequency bridge type.
All operations are performed analogously. In this case, since a proportional range is used for the left and right detection sections, the detection section G cannot be made large, so as shown in Figure 11, in order to obtain a highly accurate inclinometer, a high gain amplification is required. It is necessary to add the part (GjL). Furthermore, to obtain a high response inclinometer for dynamic applications, it is also necessary to add a feed/pull circuit with special functionality.

Furthermore, unlike the inductance type, the photoelectric type interrogator includes on/off boundary areas on both sides of the proportional area, so if it is configured as is, it may have weaknesses in terms of vibration resistance and the like. That is, if the proportional region is taken as the negative feedback operating region, the left and right boundary regions thereof become the positive feedback operating region. As a practical matter, the moving part will never enter the positive feedback region when it is operating in the negative feedback region, but when the measuring instrument moves from the stopped state to the starting state, the moving part happens to be in the positive feedback region. The movable part may be in the feedback region, or may deviate from the negative feedback region and enter the positive feedback region due to some external force during the measurement operation. In such a case, there is a risk that the reflective surface will be adsorbed to the element surface and damaged due to collision, and the close contact will make torque balance motion impossible. To prevent this, it is necessary to mechanically provide stoppers at the left and right limit points M1 and M2. However, setting the position is extremely delicate, which poses a difficult problem when adjusting the instrument.

[Means for solving problems]

In order to avoid the above-mentioned problems, the present invention sets the maximum value of the variable gap between the pixel element surface and each reflective surface to be less than the critical distance value of the on/off boundary area, and blocks the left and right light emission and reception. A high-sensitivity interrupter photoelectric converter with a built-in amplification element is used to negatively feed back the detection difference current using the on/off boundary region based on the position as the feedback operation region, and to increase the transfer function of the detection section. Hereinafter, this will be referred to as the first invention.

In addition, the present invention uses a high-sensitivity interrogator photoelectric converter as described above, and also includes left and right on/off boundary areas in the variable gap between the pixel surface and each reflective surface, and uses the left and right limit points as a base point. The above-mentioned problem could also be avoided by negative feedback of the integral value of the detected difference current using the proportional region as the feedback operation region. Below, this is the second
It's called an invention.

[Effect]

In the first invention, there is no conversion from the negative feedback area to the υ positive feedback area, and in the second invention, when the negative feedback area is converted to the positive feedback area, there is an automatic retroaction effect that brings the integral value to zero. Therefore, adsorption or collision between the left and right element surfaces and their respective opposing reflecting surfaces is avoided.

〔Example〕

[■] Embodiment of the first invention Figure 1 shows a preferred embodiment of the first invention (analog type), where Figure 0) is a plan view and Figure (B) is a side view of the main part. . In these figures, the uFi ammeter section, d is the detection section, (4) is the indicator, and (5) is the DC power supply. The zero center DC ammeter unit, which is the main body of the ammeter unit U, is small with 14 diameters and 10 cm in height in order to achieve high response dynamic applications.
A moving coil (1) supported by a movable coil with an unbalanced weight m at one end.
The pointer (2) coupled to has light reflecting surfaces F, , F2 on both sides of the other end. Reflective surface F.

High-sensitivity interrupter photoelectric converters H4 and F2 are fixed at symmetrical positions facing each other at a certain distance from F2. In the high-sensitivity interacitor photoelectric converter H1°F2, each photodetector transistor PTr1 is Darlington-connected to the transistor Tr2, and the light emitted and received by the reflecting surfaces F, F2 is amplified at a higher magnification than the Darlington circuit. . Also in this high sensitivity type (H type), pixel surface S4. The distance versus light emitting/receiving conversion value characteristic of S2 is almost the same as the characteristic curve of the normal type (G type) shown in FIG. 9(b). In the first invention, the pixel element surface S1.
S2 and reflective surface F1. The maximum value of the variable gap between F2
It is set within the boundary area of the distance vs. light emitting/receiving conversion value characteristic curve in Figure (b). That is, in the same figure, L (= 1 tm
). Therefore, in FIG. 1, F4.
When the thickness between F2 is h, the pixel surface S1. The interval g of S2 is set to be smaller than L+h. Although h is exaggerated in Figure 1 to make it easier to understand, in reality it is h = 0.1.
+ m, so the interval or gap g between the pixel surfaces is 1
．． It is about 1ms+.

FIG. 2 shows the characteristics of the above embodiment, and FIG. 2(a) shows the reflecting surface F1. F2 positive 9
Figure ←) shows the differential output characteristics of the light emitting/receiving conversion value characteristics with respect to displacement. As is clear from comparing this figure with Figure 9 and Figures 7 (a) and (b), the sensitivity (displacement vs. emitted/received light conversion value) characteristic in the boundary region is different from the sensitivity (distance vs. emitted/received light conversion value) in the proportional region. Conversion value) characteristics are much higher. Therefore, in the first invention, the transfer function of the light emission/reception conversion value of the detection section d is increased compared to the conventional type shown in FIG. The Darlington circuit of the detection section d is composed of two stages of transistors PTr1 + Tr2 as shown in FIG. If β2, the total amplification factor A is β1 and β2 in A.
becomes. Now, if we take β1=30 and β2=30, then A
= 900, compared to β = 30 for the single-stage transistor amplification in the conventional ordinary type (G type) converter shown in Fig. 8, and β = 30.
This means that the amplification current value is 0 times. Note that the Darlington circuit can also be replaced with another amplifier circuit.

FIG. 3 is a block diagram showing the operation of this embodiment. The transfer function Gd of the detection unit d in this embodiment is expressed as the transfer function G4. Comparing the conventional proportional region type and the boundary region type of this embodiment in terms of transfer function Gd□ of the light receiving input to current output ratio, the latter has a higher G than the former.

Since G is 3 times larger and Gd2 is 30 times larger, in the transfer function G of the detection section which is the product of G and 02, the latter is 90 times the former. Therefore, as shown in the block diagram of FIG.
In this embodiment, there is no need to provide an auxiliary amplifier with a transfer function G as shown in the conventional block diagram of FIG. As a result, the light emitting/receiving element of a high-sensitivity (H-type) photoelectric converter and the Darlington circuit can be integrated into a compact package, and the structure is comparable to that of a normal-type (G-type) photoelectric converter. It can be the size. Therefore, in this embodiment, as shown in FIG. 10), the output difference current from the photoelectric converter is directly fed back negatively to the movable coil (1). Note that the feedback current is indicated by an indicator (4).

As shown in FIG. 3, the difference torque ε between the input torque T1 and the feedback torque T is converted into an output value E0 by the transfer function G of the forward loop of the detector, and the output is transferred to the backward feedback loop. The feedback torque T is obtained through the transfer function G. in this way,
This embodiment has a simpler configuration than the conventional block diagram (FIG. 11).

As mentioned above, the maximum value of the variable gap between the pixel element surface and the opposing reflective surface in this embodiment is within 1 pore, and in the conventional type, the maximum value of the variable gap between the pixel element surface and the opposing reflective surface is 4 mm.
According to the conventional wisdom that the gap is too narrow, normal torque balance operation is hindered, but according to the theory of automatic control, the torque shown in Fig. 11 or Fig. 3 In the equilibrium block diagram, even if the forward-facing loop's G is on or off, as long as the gain is large, it has no bearing on the torque balance accuracy; this accuracy is solely dependent on the backward-facing loop's G, (in this case, the It is determined by the ratio between the coil current and the torque generated in the moving coil.

In a torque-balanced tilt angle measurement device that actually uses this on-off boundary area, the accuracy is ±0.1° with a maximum of ±20°.
, the accuracy was ±0.25°. This confirms the validity of the theory.

In addition, theoretically, a narrow gap under high precision means an increase in the self-oscillation frequency, which is a condition for high response control, but in reality, the feedback circuit of this embodiment has no special features. It showed a self-excitation frequency of 70 Hz up to '1 with an extremely simple configuration without adding any special functions. This indicates that it is suitable for dynamic applications.

Furthermore, even when an external impact is applied to the device, there is no risk of the pointer reflecting surface being damaged due to adsorption or collision with the fixed element surface as in conventional models, but rather has the effect of alleviating the impact force. Therefore, there is no need to provide special protection measures such as shock prevention to the main body of the device.

In the example shown in Fig. 1, a commercially available small pivot type DC ammeter was used as the main body in order to achieve high response, low cost, and miniaturization. (or a torsion gun) and allow a slight increase in size, a high-grade inclinometer with high precision and high response can be obtained.

CUE Embodiment of the Second Invention Figure 4 shows a preferred embodiment of the second invention (digital type), where 0) is a plan view and ←) is a plan view of the main parts. The ammeter unit used in this embodiment is preferably slightly larger than the one in FIG. 1, and the bearing is preferably of the tote band type. This is useful for measuring minute slopes with good reproducibility. The structure of the other ammeter units is the same as that of the first invention (analog type). That is, a pointer (2) having an unbalanced weight m at one end and coupled to a moving coil (1) has light reflecting surfaces F and F2 on both sides of the other end, and the pointer (2) has an unbalanced weight m at one end and has light reflecting surfaces F and F2 on both sides of the other end. The element surfaces S, , S2 of the high-sensitivity interacitor photoelectric converters H1 and H2 face each other.

In this embodiment, one pixel element surface S4. The gap between S2 and the opposing reflective surfaces F, , F2 is proportional to the left and right limit points M1 and M2, leaving boundary areas on the left and right sides, as in the case of using the conventional analog interrupter photoelectric converter shown in Figure 8. Set the area. Therefore, in FIG. 4, the gap g between the pixel surfaces "'11" and "2" is set to [twice the boundary area distance (
2L) +F1. The thickness between F2 is set to 111) 10-proportional range]. In this case, L = 1 m and h = 0.1
vm, and normally in the proportional region there are ± to the left and right around the equilibrium point.
Since the mounting gap is about 2, the mounting gap g is about 6.11. In the case of this embodiment, the displacement vs. light emission/reception conversion value characteristics and differential output characteristic diagrams in FIGS. 7(a) and 7(b) can be used as they are. However, the H scale on the right side is used for the differential output scale in FIG.

The second invention is of a digital type, which is different from the analog type first invention, in that the difference output of the detected current is integrated and this integrated value is negatively fed back to the proportional region. In FIG. 4, reference numeral 1 denotes an integrating section having an integrator consisting of a capacitor C and a resistor R. This RC integrator integrates the difference output current between the detection part d and the other, and outputs an output voltage E at the output terminal.

is generated, and a current proportional to this is negatively fed back to the moving coil (1). Output voltage E. is also supplied to the transmitter S.

FIG. 5 is a block diagram showing the operation of this embodiment. In the same figure, T is input torque, T is feedback torque, l
is the difference torque between Ti and T, and this torque ε is amplified by the transfer function G of the detecting section d, and passes through the transfer function 01 of the integrating section 1 to obtain the output value E0. This output value E is negatively fed back by the transfer function G of the feedback section f. The transmitter S will be described later. In FIG. 5, the waveforms of the input torque Ti and the output value E0 are added.

FIG. 6 is a waveform diagram showing this output value E0 in detail.

Output value E. is the integral of the difference output ε between the input value T1 and the feedback value T, so its output waveform is the same as the moving coil (1
) corresponds to the motion waveform of Therefore, the waveform in FIG. 6 can be treated as a motion waveform of the moving coil (1).

Now, if a positive input torque Ti is applied, the output value E
indicates its integral value, and its waveform rises from the reference zero line at an inclination angle corresponding to the input value, as shown by the solid line in FIG. Moving coil (1) and coaxial pointer (2)
) also shows the same waveform, so the movement waveform in FIG. 6 shows the movement in the proportional range of the distance vs. output characteristic in FIG. 7. Here, when the rising diagonal line reaches the height corresponding to the limit point M, and advances further and enters the boundary area, in this case, the proportional area is the negative feedback range of the integral value, and the boundary area is the positive feedback range, so As shown in FIG. 6, the output of the integrator increases rapidly, and the gap in the boundary area of the pointer (2) driven thereby approaches zero. At this time, the differential voltage shown in Figure 7, which is the input to the integrator, immediately becomes zero output when it enters the boundary region, and is further reversed, so the capacitor C of the integrator is rapidly discharged. and returns the integrating circuit to the zero position υ, and the pointer (2) also returns to the central zero position. After that, it returns to negative feedback motion and rises at the same angle of inclination as before. In this way, the pointer (2) performs a repetitive sawtooth wave motion on the positive side.

The above description is for the case where the input torque is positive, but when the input torque is negative, the motion of the sawtooth wave follows a similar course in the negative region. In FIG. 6, the motion waveform in the negative region is indicated by a broken line.

The repetition period t (t/ in the negative region) of this sawtooth wave corresponds to the input torque T1, and its sensitivity is related to the set distance of the proportional region in Fig. 7, and the larger the proportional region is, the more the same The value of t can be increased relative to the torque.

This sawtooth waveform is supplied to the transmitter S through the output terminal as shown in FIG. Branched into two positive and negative circuits,
Either the positive or negative circuit converts the 9-pulse interval into a positive or negative pulse train with or t'. This is transmitted to a predetermined remote point via a telemeter device (not shown). In addition,
In the block diagram of FIG. 5, the circuit configuration of the transmitter S shown in FIG.
2, and the transmission pulse train is also shown divided into positive and negative parts.

The second invention, as described above, forms the movable part of the tote band type zero center DC ammeter in the shape of a pendulum, detects the displacement of the pointer due to this tilting torque with an interrogator photoelectric converter,
It is an automatic balancing system in which the integral value of the differential output is fed back negatively to the moving coil, and can convert minute inclination angles into pulse intervals of a pulse train, making it suitable for telemeter measurements of inclination fluctuations in the ocean floor crust. In addition, since the wave height of the sawtooth wave is automatically switched at the conversion point between the on/off boundary region and the proportional region, a simple and highly accurate telemeter-type micro inclination angle measurement device can be used without adding any special equipment. can be obtained.

In fact, one with accuracy and accuracy of ±0.01 degrees was obtained,
Maximum inclination ± 2 degrees of inclination angle with positive or negative 2 to 2
It can be converted to a pulse interval (or 1/) of 200 seconds.

〔Effect of the invention〕

The effects of the present invention are as follows.

(a) In both the first and second inventions, there is no risk that one reflecting surface will be damaged due to adsorption or collision with the left and right element surfaces, and has the effect of mitigating external impact.

(b) According to the first invention, since the transfer function G of the detection section becomes large, an extra amplifier device is not required, and a small and highly accurate tilt angle measuring device can be obtained.

(c) The first invention has a high self-oscillation frequency and a high response, so it is suitable for dynamic applications.

The conventional inductance-type torque-balanced inclinometer shown in Figure 10 can be used satisfactorily for static applications such as measuring minute inclinations such as crustal deformation. It is necessary to add a V-f conversion device for converting into a variable low-period repetition/4' pulse train corresponding to , which has the disadvantage that the device becomes large. On the other hand, according to the second aspect of the invention, there is no need to add an extra Vf converter by negatively feeding back the integral value of the detected difference current.

(E) The second invention is suitable for a telemeter-type tilt angle measuring device with high precision and high sensitivity, since a minute tilt angle can be converted into a pulse interval of a pulse train.

[Brief Description of the Drawings] Fig. 1 is a diagram showing an embodiment of the first invention, Fig. 2 is a diagram showing its characteristics, Fig. 3 is a block diagram showing its operation, and Fig. 4 is a diagram showing the embodiment of the second invention. FIG. 5 is a block diagram showing its operation; FIG. 6 is a diagram showing its output frost and pressure waveform; FIG. 7 is a diagram showing the characteristics of the high-sensitivity interrupter photoelectric converter used in the present invention. , FIG. 8 is a diagram showing a conventional interrupter photoelectric conversion type measurement device, FIG. 9 is a diagram showing the interrupter photoelectric converter and its characteristics, FIG. 10 is a diagram showing a conventional inductance type torque balance inclinometer, FIG. 11 is a block diagram showing its operation, FIG. 12 is a diagram showing the characteristics of the inductance converter, and FIG. 13 is a diagram showing the characteristics of the inclinometer shown in FIG. (1)...Movable coil, (2)...Pointer 1m...
Unbalanced 1 sleep, Fl, F2... light reflecting surface, leaf... light emitting element, PTrl... light receiving element, Tr2... amplifying element,
Hl, H2... Interacitor photoelectric converter, Sl, 8
2... Left and right element surfaces, L... Limit distance of on/off boundary area, M11M2... Left and right limit points, C, R... Integrating means.

Claims (1)

[Claims] 1. A pointer connected to a moving coil of a zero-center DC ammeter and having an unbalanced weight at one end, with light reflecting surfaces on both sides of the other end,
An interrupter photoelectric converter configured such that light emitting/receiving elements are fixed at symmetrical positions on these reflective surfaces at opposing distances, and the emitting/receiving light conversion values corresponding to the above-mentioned opposing distances by the left and right elements are amplified and detected by respective amplifying elements. In this method, the maximum value of the variable gap between the left and right element surfaces and their respective opposing reflecting surfaces is set to be less than the critical distance of the on/off boundary area in the light emission/reception conversion characteristics, and the on/off state is set from the left and right light emission/reception cutoff positions as a base point. A torque-balanced inclination angle measuring device characterized in that the off-boundary region is an operating region of a feedback current, and the detected difference current is negatively fed back to the movable coil in the operating region. 2. A pointer connected to the moving coil of the zero center DC ammeter and having an unbalanced weight at one end has light reflecting surfaces on both sides of the other end,
An interrupter photoelectric converter configured such that light emitting/receiving elements are fixed at symmetrical positions on these reflective surfaces at opposing distances, and the emitting/receiving light conversion values corresponding to the above-mentioned opposing distances by the left and right elements are amplified and detected by respective amplifying elements. In the above, the variable gap between the left and right element surfaces and the respective opposing reflecting surfaces includes the left and right on/off boundary regions in the light emitting and receiving conversion characteristics, and the proportional region based on the left and right limit points is the operating region of the feedback current, A torque-balanced inclination angle measuring device characterized in that an integral value of the detected difference current is negatively fed back to the movable coil in the operating range.