JPH10176926A - Inclination meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction-type inclination meter in non-contact structure and a simple configuration. SOLUTION: An inclination meter has an accommodation body containing a passage 1a that is curved downward, a magnetic response member 3 that is accommodated in the passage 1a so that it can travel freely according to gravity, and a coil part 2 that is provided at the outer periphery of the passage 1a in the accommodation body 1. In this case, the magnetic response member 3 is displaced along the passage 1a according to the inclination of the accommodation body 1 and the coil part 2 obtains an induction output signal for detecting the position of the magnetic response member 3 in the passage 1a, thus detecting an inclination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inclinometer for detecting an inclination in a predetermined direction, and is applicable to construction machines, automobiles, machine tools, and all other fields.

[0002]

2. Description of the Related Art Some conventional tilt detecting devices use a potentiometer. However, the potentiometer has a sliding contact, which is difficult in terms of durability.
Further, in the conventionally known inductive type position detecting device, there is a differential transformer as a linear position detecting device, and a resolver as a rotational position detecting device. The differential transformer is one of
The secondary winding is excited in one phase to generate reluctance that changes differentially according to the linear position of the iron core interlocking with the position to be detected at each position of the two secondary windings that are differentially connected. The voltage amplitude level of the resulting one-phase inductive output AC signal indicates the linear position of the iron core. The resolver excites a plurality of primary windings in one phase, extracts an output AC signal indicating a sine phase amplitude function characteristic from the sine phase extracting secondary winding, and extracts the cosine phase extracting secondary winding from the secondary winding. An output AC signal showing an amplitude function characteristic of a cosine phase is taken out.
The two-phase resolver output is processed using a known conversion circuit called an R / D converter, and a phase value corresponding to the detected rotational position can be digitally measured.
Also, an output AC signal in which a plurality of primary windings are respectively excited by AC signals of a plurality of phases such as a sine phase and a cosine phase, and the AC signal is electrically phase-shifted according to a linear position or a rotational position to be detected. There is also known a technique for digitally measuring a linear position or a rotational position of a detection target by measuring the electric phase shift amount of the output AC signal (for example, Japanese Patent Application Laid-Open No. 49-107758, JP-A-53-106065, JP-A-55-13891, Japanese Utility Model Publication 1-25286, etc.).

[0003]

However, a potentiometer conventionally known as an inclination detecting device is, as described above,
Due to the presence of the sliding contact, there was difficulty in terms of durability. Moreover, it was not suitable for use in a poor environment. In addition, the conventionally known inductive position detecting device detects a rotational position or a linear position, and does not have a structure capable of detecting an inclination. In general, an inductive position detecting device is structurally non-contact, and can be manufactured simply and inexpensively with a simple configuration of a coil and a magnetic body (such as an iron piece). Since it can withstand use, if it can be applied to a tilt detection device, wide applications and applications are expected. The present invention has been made in view of the above points, and has as its object to provide a new inductive inclinometer that has not been available in the past.

[0004]

The inclinometer according to the present invention comprises:
A housing including a passage curved downward, a magnetic response member housed movably according to gravity in the passage, and a coil portion provided on an outer periphery of the passage in the housing; The magnetic response member is displaced along the passage according to the inclination of the storage body, and the inclination is detected by obtaining an induction output signal for detecting a position of the magnetic response member in the passage from the coil unit. It is a feature. Since the passage of the storage body is curved downward, when the storage body is placed in the horizontal position, the magnetic response member in the passage is necessarily at a predetermined position (the one corresponding to the inclination 0) by its own weight. (Lowest position). When the storage body tilts,
Accordingly, the magnetic response member is displaced along the passage, and an induction output signal for detecting the position of the magnetic response member in the passage is obtained from the coil unit. The output signal of the coil unit responds to the inclination of the housing.

[0005] In one embodiment, the coil section may be provided with a plurality of coils along a passage. Further, the coil section is excited by a one-phase AC signal, and outputs an output AC signal indicating an amplitude function characteristic of a sine phase and an output AC signal indicating an amplitude function characteristic of a cosine phase according to a relative position of the magnetic response member. It may be configured based on the resolver-type position detection principle so as to output a two-phase output AC signal with a signal. In that case, based on the output AC signal indicating the amplitude function characteristic of the sine phase and the output AC signal indicating the amplitude function characteristic of the cosine phase, the phase values of the amplitude function of the sine phase and the amplitude function of the cosine phase are detected. By further providing a phase detection circuit that obtains phase value detection data according to the relative position of the magnetic response member, it is possible to provide a highly accurate device that is less susceptible to changes in the temperature of the surrounding environment and the like. it can. According to one embodiment, the magnetically responsive member may be made of a solid, such as a sphere or a column. As another example, the magnetic response member is not limited to a solid, and may be formed of an object having a non-fixed shape. For example, a magnetic fluid or a magnetic powder can be used.

[0006] The inclinometer as described above detects an inclination in only one direction along the direction of the passage. For example, when the target inclination direction is determined to be one predetermined direction as in the detection of the inclination of the work arm of the construction machine, one inclinometer may be provided. However, when it is desired to detect the inclination in at least two directions, such as when detecting the inclination of the vehicle body in the front-rear direction and the inclination in the left-right lateral direction, at least two such inclination detection devices are provided in predetermined directions different from each other (for example, X-axis). Direction and the Y-axis direction). According to the invention, further various embodiments are possible, the details of which are given by way of example below.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the accompanying drawings. The illustrated examples can be combined with each other, and such combinations are also included in the implementation of the present invention. FIG. 1 is an axial sectional view of an inclinometer 10 according to the present invention. The housing 1 made of a non-magnetic material such as plastic or stainless steel has a shape like a winding shaft, and a passage 1a curved downward is provided inside the shaft as shown in the figure. . A magnetic responsive member 3 of an appropriate size or amount is movably accommodated in the passage 1a according to gravity. In the example of FIG. 1, the magnetic response member 3 is made of a magnetic material such as iron having a spherical shape. One or a plurality of coils 11 to 15, 21 to 24 are sequentially arranged and wound around the passage 1a of the storage body 1, that is, around the winding shaft. The coil unit 2 is constituted by these coils 11 to 15 and 21 to 24. Note that both ends of the passage 1a are closed so that the magnetic response member 3 inside does not protrude.

With the above configuration, the inductive coupling in the coil portion 2 changes according to the linear position of the magnetic response member 3 in the passage 1a, that is, the linear position of the magnetic response member 3 relative to the coil portion 2. A corresponding output signal can be obtained from the coil unit 2. Therefore, passage 1a
A detection output signal corresponding to the linear position of the magnetic response member 3 in the inside can be obtained from the coil unit 2.
Here, since the passage 1a of the storage body 1 is bent downward, when the storage body 1 is placed in the horizontal position, the magnetic response member 3 in the passage 1a always becomes a predetermined weight by its own weight. Position (the lowest position corresponding to the inclination 0). When the housing 1 is tilted, the magnetic response member 3 is linearly displaced along the passage 1a, and a detection output signal corresponding to the linear position of the magnetic response member 3 in the passage 1a is obtained from the coil unit 2. Can be Therefore, the output signal of the coil unit 2 responds to the inclination of the housing 1, and can be used as a detection signal of the inclination as appropriate.

Any principle can be used as the detection principle by the coil section 2. As a simple example, there may be a pickup coil system. That is, based on output signal levels of a plurality of coils arranged along the passage 1a,
By specifying the coil closest to the magnetic responsive member 3, the linear position of the magnetic responsive member 3 in the passage 1a can be detected, and therefore, the degree of inclination of the housing 1 can be detected / detected. As an example for detecting the linear position of the magnetic response member 3 more finely, the coil section 2 can be configured according to the linear differential transformer principle. That is, one or a plurality of linear differential transformers are configured as the coil unit 2, and the pickup is determined by a combination of an output voltage value of the linear differential transformer and data indicating from which linear differential transformer the output is obtained. The linear position of the magnetic responsive member 3 can be detected with higher precision than the coil method.

In order to detect the linear position of the magnetically responsive member 3 more precisely and more precisely, the coil unit 2 may be configured according to the principle of the resolver. When the coil unit 2 is configured according to the resolver principle, the coil unit 2 includes primary coils 11 to 15 that are excited by one-phase AC signals and a plurality of secondary coils 21 to 24. Each secondary coil 21-
24 are arranged at predetermined intervals along the passage 1a. On the other hand, the number of the primary coils 11 to 15 may be one or an appropriate plural number, and the arrangement thereof may be appropriate because the excitation is commonly performed by the one-phase AC signal. However, a plurality of primary coils 11 to 15 are appropriately separated, and, for example, as shown in FIG. This is preferable because the generated magnetic field can be effectively applied to the individual secondary coils 21 to 24 and the magnetic response member 3 can effectively affect the magnetic field.

The corresponding position of the magnetic response member 3 with respect to the coil portion 2 changes in accordance with the linear position of the magnetic response member 3 in the passage 1a, so that the primary coils 11 to 15 and each of the secondary coils 21 to 24 change. The magnetic coupling is changed in accordance with the linear position, whereby the inductive output AC signal whose amplitude has been modulated in accordance with the linear position is changed by each of the secondary coils 21 to 21.
24 with different amplitude function characteristics depending on the displacement of
It is induced in the next coils 21 to 24. Each secondary coil 21-
24, each of the induced output AC signals is a primary coil 1
Since 1 to 15 are commonly excited by a single-phase AC signal, their electric phases are the same, and their amplitude functions have phases shifted according to the shift of the arrangement of each of the secondary coils 21 to 24. . That is, it is possible to set the amplitude function of the induced output AC signal generated in the four secondary coils 21 to 24 so as to exhibit desired characteristics. Next coil 21-
24, the sine function, cosine function, minus sine function, minus
Can be set to correspond to cosine functions, respectively. The arrangement of each coil can be slightly changed depending on various conditions. Therefore, the arrangement and the number of turns of each coil are appropriately adjusted so as to obtain a desired function characteristic, or
The next output level is adjusted by electrical amplification so that the desired amplitude function characteristic is finally obtained.

For example, assuming that the output of the secondary coil 21 corresponds to a sine function (suffix s in the figure), the secondary coil 21 is disposed at a predetermined distance (for example, p / 2) from the sine function. 23 is set so as to correspond to a minus sine function (/ s (s bar) is added in the figure), and by combining these two outputs differentially, a signal having an amplitude function of a sine function is obtained. One output AC signal can be obtained. Further, a half of the predetermined distance from the secondary coil 21 corresponding to the sine function output (for example, p / 4
The output of the secondary coil 22 shifted by p / 2 corresponds to a cosine function (c is added in the figure), whereas the output of the secondary coil 24 shifted by p / 2 is A second output AC having an amplitude function of a cosine function is set by correspondingly setting a negative cosine function (/ c (c bar) is added in the figure), and by combining these two outputs differentially. A signal can be obtained. In the specification, for convenience of notation, a bar symbol indicating inversion is described as “/ (slash)”, which corresponds to the bar symbol in the figure.

FIG. 2 is a circuit diagram of the primary and secondary coils of the coil unit 2. A common excitation AC signal (indicated by sinωt for convenience of explanation) is applied to the primary coils 11 to 15. In response to the excitation of the primary coil, an AC signal having an amplitude value corresponding to the linear position of the magnetic response member 3 that changes in accordance with the inclination angle α of the housing 1 is guided to each of the secondary coils 21 to 24. You. Each of the induced voltage levels shows two-phase function characteristics sin θ and cos θ having a phase angle θ correlated with the inclination angle α and function characteristics −sin θ and −cos θ of the opposite phase. That is,
The induction output signal of each of the secondary coils 21 to 24 is calculated based on the inclination angle α.
Function characteristic sin θ, c corresponding to the phase angle θ correlated to
It can be set so as to be output in a state of being amplitude-modulated by osθ and its inverse phase function characteristics −sinθ and −cosθ. For convenience of explanation, coefficients according to other conditions such as the number of turns of the coil are omitted, and the secondary coil 21 is used as a sine phase.
The output signal is represented by “sinθ · sinωt”, and the output signal is represented by “cosθ · sin
ωt ”. The output signal of the secondary coil 23 is represented by “−sin θ · sin ωt”, and the output signal thereof is represented by “−cos θ · sin ωt”. A first output AC signal A (= 2 sin θ · sin ωt) having a sine function amplitude function is obtained by differentially combining the induced outputs of the sine phase and the minus sine phase. A second output AC signal B (= 2 cos θ · sin ωt) having a cosine function amplitude function is obtained by differentially combining the induced outputs of the cosine phase and the negative cosine phase. In addition,
For simplicity of expression, the coefficient “2” is omitted, and hereinafter, the first output AC signal A is represented by “sinθ · sinωt”, and the second output AC signal B is represented by “cosθ · sinωt”. Express.

Thus, the first output AC signal A = sinθ · sinωt having the amplitude value of the first function value sinθ having the phase angle θ correlated to the inclination angle α, and the second output AC signal A corresponding to the same phase angle θ A second output AC signal B = cos θ · sin ωt having the function value cos θ as the amplitude value is output. According to such a coil configuration, two output AC signals A and A having a two-phase amplitude function, which are in-phase AC and similar to those obtained in a resolver conventionally known as a rotary position detecting device, are obtained.
It can be understood that B (sine output and cosine output) can be obtained from the coil unit 2. A two-phase output AC signal (A = sin θ · sin ωt and B
= Cosθ · sinωt) can be used in the same manner as the output of a conventionally known resolver. For example, as shown in FIG. 2, the output AC signals A and B of the coil unit 2 are input to an appropriate digital phase detection circuit 40, and the sine function sin
and the phase value θ of the cosine function cos θ is detected by a digital phase detection method, and the digital data D of the phase angle θ is detected.
θ can be obtained. Therefore, the digital data Dθ can be used as the detection data of the inclination angle α. As a digital phase detection method employed in the digital phase detection circuit 40, a known RD (resolver-digital) converter may be applied, or a new method developed by the present inventors may be employed. Good.

The shape of the magnetic response member 3 is not limited to a sphere, but may be a cylindrical shape or any other appropriate shape. Further, the magnetic response member 3 is not limited to a solid member, and may be made of a non-fixed object such as a magnetic fluid or a magnetic powder. Further, the material of the magnetic response member 3 is not limited to a magnetic material, and may be a good conductor such as copper. FIGS. 3A and 3B show some modified examples of the magnetic response member 3, and FIG. 3A shows a solid magnetic response member 3a having a cylindrical shape. (B) shows an example in which an appropriate amount of the magnetic fluid 3b is used as the magnetic response member 3.
(C) shows an example in which an appropriate amount of magnetic powder 3c is used as the magnetic response member 3. The magnetic powder 3c is not limited to a fine powder, and may be a granular material such as iron sand. Although not particularly shown, depending on the purpose of use, when a solid magnetic responsive member 3 as shown in FIG. 1 is used, a non-magnetic viscous fluid is sealed in the passage 1a, and the magnetic responsive member 3 corresponding to the inclination is used. A suitable amount of dumping action may be exerted on the movement of.

In FIG. 1, the appearance of the storage body 1 is like a bobbin or a winding shaft. However, the present invention is not limited to this, and the storage body 1 may have a bent tube shape as shown in FIG. In that case, the coil part 2 is fitted around the bent tube (storage body 1). Further, in each of the above-described embodiments, the number and arrangement of the primary and secondary coils in the coil unit 2 can be variously modified or changed in design. Also, the number of phases of the secondary coil output signal is not limited to two phases of sine and cosine, but may be another form, for example, a three-phase type shifted by 120 degrees.

The inclinometer 10 as described above can detect inclination only in one direction (one axis) along the direction of the passage 1a. For example, when the target inclination direction is determined to be one predetermined direction as in the detection of the inclination of the work arm of the construction machine, one inclinometer 10 may be provided. However, when it is desired to detect the inclination in at least two directions, such as when the front and rear inclination and the left and right inclination of the vehicle body are detected, or in other cases, at least two inclinometers 10 different from each other are used. May be arranged in the direction of. For example, FIG. 5 schematically shows an example in which two inclinometers 10X and 10Y are combined so as to cross each other at an angle of 90 degrees. Each of the inclinometers 10X and 10Y is the inclinometer 1 described above.
0 and the same configuration. Thus, the inclination (incline component) of the detection target in the X-axis direction can be detected by the inclinometer 10X, and the inclination (incline component) of the detection target in the Y-axis direction can be detected by the inclinometer 10Y.

FIG. 6 shows a modification of FIG. 5, in which the curvature of the passage 1a in the housing 1 of the inclinometers 10X 'and 10Y' corresponding to the X and Y axes is enlarged. As described above, the larger the curvature of the passage 1a, the smaller the displacement of the magnetic response member 3 with respect to the actual inclination angle α (the more difficult it is to move in the passage 1a). Therefore, by adjusting the curvature of the passage 1a in the housing 1, the sensitivity of the inclination angle α to be detected can be adjusted or the detectable angle range can be adjusted. As can be easily understood, having the detection sensitivity or the range adjusting function by adjusting the curvature of the passage 1a as described above, according to the present invention, the presence or absence of the inclination in response to the inclination over a predetermined range or a predetermined range. It also means that an inclinometer capable of detecting can be provided. Of course, even in the one-axis type inclinometer 10, the detection sensitivity or the range can be adjusted by adjusting the curvature of the passage 1a.

FIG. 7 shows an example in which a known RD (resolver-digital) converter is applied as the digital phase detection circuit 40. Secondary coils 21 and 2 of coil unit 2
A = sin θ · sin ωt and B = cos θ · sin ωt of the resolver type two-phase output AC signals output from the analog multipliers 30 and 31 are input to the analog multipliers 30 and 31, respectively. The phase generating circuit 32 sequentially generates digital data of the phase angle φ, and the sine / cosine generating circuit 33 generates an analog signal of a sine value sinφ and a cosine value cosφ corresponding to the phase angle φ. In the multiplier 30, the sine phase output AC signal A = sin
θ · sinωt is multiplied by the cosine value cosφ from the sine / cosine generating circuit 33 to obtain “cosφ · sinθ · sinωt”.
Get. The other multiplier 31 multiplies the cosine phase output AC signal B = cos θ · sin ωt by the sine value sin φ from the sine / cosine generating circuit 33 to obtain “sin φ · c
osθ · sinωt ”. In the subtractor 34, both multipliers 30,
The difference between the output signals of the phase generator 31 is obtained, and the phase generation operation of the phase generator 32 is sequentially controlled by the output of the subtractor 34 as follows. That is, the generated phase angle φ of the phase generating circuit 32 is reset to 0 at first, and then sequentially increased,
When the output of the subtractor 34 becomes 0, the increase is stopped. The output of the subtractor 34 becomes 0 because “cosφ · sinθ · sinω
t ”=“ sin φ · cos θ · sin ωt ”, that is, φ = θ is satisfied, and the phase generation circuit 32
From the output AC signals A and B
And the digital value of the phase angle θ of the amplitude function.
Accordingly, a reset trigger is periodically given at an arbitrary timing to sequentially reset the generated phase angle φ of the phase generation circuit 32 to 0, start incrementing the phase angle φ, and the output of the subtractor 34 becomes 0 When this happens, the increment is stopped and digital data of the phase angle θ is obtained. It is known that the phase generating circuit 32 is configured to include an up / down counter and a VCO, and the output of the subtractor 34 drives the VCO to control the up / down counting operation of the up / down counter. In that case, a periodic reset trigger is unnecessary.

An error occurs in the electrical AC phase ωt of the secondary output AC signal due to a change in the impedance of the primary and secondary coils of the coil unit 2 due to a temperature change or the like. , Sinωt
Is automatically canceled out, which is advantageous.
On the other hand, conventionally known two-phase AC signals (for example, sin
ωt and cosωt), a system in which an electric phase shift is generated in a one-phase output AC signal by exciting in
The output phase error based on such a temperature change cannot be removed. By the way, the conventional RD as described above
Since the phase detection circuit including the converter is a tracking comparison method, there is a problem that a clock delay occurs when φ is tracked and counted, resulting in poor response. Therefore, the present inventors have developed a novel phase detection circuit as described below, and it is convenient to use this.

FIG. 8 shows an embodiment of a novel digital phase detection circuit 40 applied to the tilt detection device according to the present invention. 8, in a detection circuit section 41, a predetermined high-speed clock pulse CK is counted by a counter 42, and an excitation AC signal (for example, sinωt) is generated from an excitation signal generation circuit 43 based on the count value. Of the primary coils 11 to 15 are given. The modulo number of the counter 42 corresponds to one cycle of the exciting AC signal, and for convenience of explanation, it is assumed that the count value 0 corresponds to the zero phase of the reference sine signal sinωt. Two-phase output AC signals output from the secondary coils 21 to 24 of the coil unit 2 A = sinθ · sinωt and B = cosθ · sinωt
Is input to the detection circuit unit 41.

In the detection circuit section 41, the first AC output signal A = sin θ · sin ωt is input to the phase shift circuit 44, and its electric phase is phase-shifted by a predetermined amount.
AC signal A '= sin advanced by 0 degree and phase shifted
θ · cosωt is obtained. Further, in the detection circuit section 41, an addition circuit 45 and a subtraction circuit 46 are provided. In the addition circuit 45, the phase-shifted AC signal A ′ = sinθ · cosωt output from the phase shift circuit 44 and the coil The second AC output signal B = cosθ · sinωt output from the secondary coils 21 to 24 of the unit 10 is added, and the added output is B + A ′ = cosθ · sinωt + sinθ · cosω.
As a result, a first electrical AC signal Y1 can be obtained, which can be represented by a simplified expression t = sin (ωt + θ). In the subtraction circuit 46, the phase-shifted AC signal A ′ = sin θ · cosωt and the second
Is subtracted from the AC output signal B = cos θ · sin ωt, and as a subtraction output, BA ′ = cos θ · sin ωt−sin θ · cos
A second electrical AC signal Y2 can be obtained, which can be represented by a simplified expression ωt = sin (ωt−θ). Thus, the passage 1a
The same linear position as the first electric AC signal Y1 = sin (ωt + θ) having the electric phase angle (+ θ) shifted in the positive direction corresponding to the linear position (x) of the magnetic response member 3 A second electric AC signal Y2 = sin having an electric phase angle (−θ) shifted in the negative direction corresponding to (x)
(Ωt−θ) can be obtained by electrical processing.

The output signals Y1 and Y2 of the adder circuit 45 and the subtractor circuit 46 are input to zero-cross detection circuits 47 and 48, respectively, where the respective zero-crosses are detected. As a method of detecting the zero cross, for example, a zero cross in which the amplitude values of the signals Y1 and Y2 change from negative to positive, that is, zero phase is detected. The zero-cross detection pulse, that is, the zero-phase detection pulse detected by each of the circuits 47 and 48 is a latch pulse LP
1 and LP2 are input to the latch circuits 49 and 50. The latch circuits 49 and 50 latch the count value of the counter 42 at the timing of the respective latch pulses LP1 and LP2. As described above, the modulo number of the counter 42 corresponds to one cycle of the exciting AC signal, and the count value of 0 corresponds to the 0 phase of the reference sine signal sinωt. The data D1 and D2 latched by the latch circuits 49 and 50 respectively correspond to the phase shifts of the output signals Y1 and Y2 with respect to the reference sine signal sinωt. The output of each of the latch circuits 49 and 50 is input to the error calculation circuit 51, and "(D1 + D2) / 2"
Is calculated. Note that this calculation is actually “D
This may be performed by shifting the addition result of the binary data of “1 + D2” by one bit lower.

Here, the influence of the length of the wiring cable between the coil unit 2 and the detection circuit unit 41, the influence of each length of the coil unit 2,
Taking into account that an impedance change due to a temperature change or the like occurs in the secondary and secondary coils, the phase variation error of the output signal is indicated by “± d”. Is represented by A = sinθ · sin (ωt ± d) A ′ = sinθ · cos (ωt ± d) B = cosθ · sin (ωt ± d) Y1 = sin (ωt ± d + θ) Y2 = sin (ωt ± d−θ) D1 = ± d + θ D2 = ± d-θ

That is, each phase shift measurement data D1, D
No. 2 performs the phase shift count using the reference sine signal sinωt as the reference phase, so that a value including the phase variation error “± d” is obtained as described above. Therefore, the error calculation circuit 51 calculates “(D1 + D2) / 2” to obtain (D1 + D2) / 2 = {(± d + θ) + (± d−θ)} / 2 = ± 2d / 2 = ± By using d, the phase fluctuation error “± d” can be calculated.

The data of the phase variation error “± d” obtained by the error calculation circuit 51 is supplied to a subtraction circuit 52, and is subtracted from one phase shift measurement data D1. That is,
In the subtraction circuit 52, since the subtraction of “D1− (± d)” is performed, D1− (± d) = ± d + θ− (± d) = θ, and the correct detection after removing the phase variation error “± d” Digital data indicating the phase difference θ is obtained. As described above, according to the present invention, it can be understood that the phase fluctuation error “± d” is canceled and only the correct phase difference θ is extracted.

This point will be further described with reference to FIG. FIG.
, The sine signal sinωt serving as a reference for phase measurement
5A and 5B show waveforms near the zero phase of the first and second AC signals Y1 and Y2. FIG. 5A shows a case where the phase fluctuation error is plus (+ d), and FIG. d) is shown. In the case of FIG. 9A, the zero phase of the first signal Y1 is advanced by “θ + d” with respect to the zero phase of the reference sine signal sinωt, and the corresponding phase difference detection data D1 is “θ + d”. The corresponding phase difference is shown. Further, the 0 phase of the second signal Y2 is delayed by “−θ + d” with respect to the 0 phase of the reference sine signal sinωt, and the corresponding phase difference detection data D2 has a phase difference corresponding to “−θ + d”. Is shown. In this case, the error calculation circuit 51 calculates the phase fluctuation error “+ d” according to (D1 + D2) / 2 = {(+ d + θ) + (+ d−θ)} / 2 = + 2d / 2 = + d. Then, D1-(+ d) = + d + θ − (+ d) = θ is calculated by the subtraction circuit 52, and the correct phase difference θ is extracted.

In the case of FIG. 9B, the reference sine signal sin
The 0 phase of the first signal Y1 is “θ−
d ”, and the corresponding phase difference detection data D1 indicates a phase difference corresponding to“ θ−d ”. Also, the second signal Y2 with respect to the zero phase of the reference sine signal sinωt
Is delayed by “−θ−d”, and the corresponding phase difference detection data D2 indicates a phase difference corresponding to “−θ−d”. In this case, the error calculation circuit 51 calculates the phase fluctuation error “−d” according to (D1 + D2) / 2 = {(− d + θ) + (− d−θ)} / 2 = −2d / 2 = −d . Then, D1-(− d) = − d + θ − (− d) = θ is calculated by the subtraction circuit 52, and a correct phase difference θ is extracted. In the subtraction circuit 52, A subtraction of “D2− (± d)” may be performed, and in principle, the correct phase difference θ
It can be understood that data (−θ) reflecting the above is obtained.

Further, as can be understood from FIG.
The electrical phase difference between the signal Y1 and the second signal Y2 is 2
θ, which always indicates an accurate double value of the phase difference θ in which the phase fluctuation error “± d” in both cases is cancelled. Therefore, the configuration of the circuit portion including the latch circuits 49 and 50, the error calculation circuit 51, and the subtraction circuit 52 in FIG. 8 is appropriately changed to a configuration for directly obtaining the electrical phase difference 2θ between the signals Y1 and Y2. It may be.
For example, from the point in time when the pulse LP1 corresponding to the zero phase of the first signal Y1 output from the zero-cross detection circuit 47 occurs, the pulse LP2 corresponding to the zero phase of the second signal Y2 output from the zero-cross detection circuit 48 By gating by an appropriate means until the time of occurrence, and counting this gate period, digital data corresponding to the electrical phase difference (2θ) can be obtained in which the phase fluctuation error “± d” is canceled. , Is shifted one bit lower, data corresponding to θ is obtained.

In the above embodiment, the output of the same counter 42 is latched by the latch circuit 49 for latching + θ and the latch circuit 50 for latching -θ. No particular reference is made to the sign of. However, the sign of the data may be subjected to appropriate design processing so as to conform to the gist of the present invention. For example, assuming that the modulo number of the counter 42 is 4096 (decimal notation), the digital counts 0 to 4095 may be appropriately processed according to the phase angle of 0 to 360 degrees. In the simplest design example, the most significant bit of the count output of the counter 42 is a sign bit, the digital counts 0 to 2047 correspond to +0 to +180 degrees, and the digital counts 2048 to 4095 correspond to −180 to −0.
The arithmetic processing may be performed in accordance with the degree.
Alternatively, as another example, by converting input data or output data of the latch circuit 50 into a two's complement number, the digital counts 4095-0 are made to correspond to negative angle data expressions of -360 degrees to -0 degrees. You may.

There is no particular problem when the tilt angle α is stationary, but when the detection target tilt angle α changes with time, the corresponding linear position (x), that is, the phase angle θ, also changes with time. Will fluctuate. In that case,
Output signals Y1 and Y2 of the addition circuit 45 and the subtraction circuit 46
Is not a constant value, but shows a dynamic characteristic that changes with time according to the moving speed.
As shown by (t), the output signals Y1 and Y2 are as follows: Y1 = sin {ωt ± d + θ (t)} Y2 = sin {ωt ± d−θ (t)} That is, with respect to the frequency of the reference signal sinωt, the leading output signal Y1 makes a frequency transition in a direction of increasing the frequency in accordance with + θ (t), and the lagging output signal Y2 becomes −θ.
Frequency transition is performed in a direction in which the frequency becomes lower according to (t).
Under such dynamic characteristics, the periods of the signals Y1 and Y2 transition in the opposite directions one after another for each period of the reference signal sinωt. The measurement time reference for D2 will be different, and both data D1 and D2 will simply be
By simply performing the calculations at 1, 52, the accurate phase variation error “±
d "cannot be obtained.

The simplest method for avoiding such a problem is to ignore the output when the tilt angle α is temporally moving and use only the output when the tilt angle α is stationary in the configuration of FIG. Therefore, the function of the apparatus is limited so as to measure the inclination angle α when the stationary state is obtained. That is,
The invention may be practiced for such limited purposes. However, the detection target inclination angle α
It is desirable to be able to accurately detect the phase difference θ corresponding to the detection target inclination angle α every moment even while the time is changing with time. Therefore, in order to solve the above-described problem, even when the detection target inclination angle α is changing with time, the detection target inclination angle α is momentarily changed.
With reference to FIG. 10, a description will be given of an improvement measure that makes it possible to detect the phase difference θ corresponding to.

FIG. 10 shows a modified example of a part of the error calculation circuit 51 and the subtraction circuit 52 in the detection circuit part 41 of FIG. 8, and the configuration of other parts not shown is shown in FIG.
May be the same as The phase difference θ corresponding to the inclination angle θ when the detection target inclination angle θ changes with time
Are represented by + θ (t) and −θ (t), the output signals Y1 and Y2 can be represented as described above. The phase shift measurement value data D1 and D2 obtained by the latch circuits 49 and 50 respectively become D1 = ± d + θ (t) and D2 = ± d−θ (t). In this case, ± d + θ (t) repeatedly temporally changes in the plus direction from 0 ° to 360 ° in accordance with the temporal change of θ. Further, ± d-θ (t) repeatedly and temporally changes in the minus direction from 360 degrees to 0 degrees in accordance with the temporal change of θ. Therefore, ± d
+ Θ (t) ≠ ± d-θ (t), but sometimes both changes intersect, in which case ± d + θ (t) = ±
d−θ (t) holds. Thus, ± d + θ (t) =
When ± d-θ (t) holds, the output signals Y1, Y2
Of the latch pulses LP1 and LP2 corresponding to the respective zero-cross detection timings.
Are coincident with each other.

In FIG. 10, the coincidence detection circuit 53 detects that the generation timings of the latch pulses LP1 and LP2 corresponding to the zero-cross detection timing of each of the output signals Y1 and Y2 coincide, and responds to this detection. A coincidence detection pulse EQP is generated. On the other hand, the time variation determination circuit 54
Then, by appropriate means (for example, by detecting the presence or absence of a temporal change in the value of one phase difference measurement data D1), it is determined that the mode is such that the detection target inclination angle α temporally changes. , The time-varying mode signal T
Output M. A selector 55 is provided between the error calculation circuit 51 and the subtraction circuit 52, and when the time variation mode signal TM is not generated, that is, TM = “0”, that is, the detection target inclination angle θ changes with time. If not, the output of the error calculation circuit 51 added to the selector input B is selected and input to the subtraction circuit 52. As described above, when the input B of the selector 55 is selected, the circuit of FIG.
It operates equivalently to the circuit of FIG. That is, when the detection target is stationary, the output data of the error calculation circuit 51 is directly supplied to the subtraction circuit 52 via the input B of the selector 55, and operates similarly to the circuit of FIG.

On the other hand, when the time-varying mode signal TM is generated, that is, when TM = “1”, that is, when the detection target is changing with time, the output of the latch circuit 56 added to the input A of the selector 55 is output. Is selected and input to the subtraction circuit 52. When the time variation mode signal TM is "1" and the coincidence detection pulse EQP is generated, the condition of the AND gate 57 is satisfied, and a pulse responsive to the coincidence detection pulse EQP is output from the AND gate 57. , And a latch instruction to the latch circuit 56. Latch circuit 5
6 latches the output count data of the counter 42 according to the latch instruction. Here, the coincidence detection pulse EQ
When P occurs, the output of the counter 42 is
9 and 50 at the same time, so that D1 = D
2 and the data latched by the latch circuit 56 is D1
Or D2 (where D1 = D2).

The coincidence detection pulse EQP is generated when the zero-cross detection timing of each of the output signals Y1 and Y2 coincides, that is, when “± d + θ (t) = ± d−θ (t)” is satisfied. Therefore, in response to this, the latch circuit 5
6 is D1 or D2 (where D1
= D2), which is equivalent to (D1 + D2) / 2. This means that (D1 + D2) / 2 = [{± d + θ (t)} + {± d−θ (t)}] / 2 = 2 (± d) / 2 = ± d. The data latched by the circuit 56 means that the data accurately indicates the phase fluctuation error “± d”.

As described above, when the detection target fluctuates with time, data accurately indicating the phase fluctuation error "± d" is latched by the latch circuit 56 in accordance with the coincidence detection pulse EQP. The output data is the selector 55
Is supplied to the subtraction circuit 52 through the input A. Therefore,
The subtraction circuit 52 can obtain data θ (θ (t) if it fluctuates over time) that accurately responds only to the detection target inclination angle θ from which the phase fluctuation error “± d” has been removed. In addition,
In FIG. 10, the AND gate 57 may be omitted, and the coincidence detection pulse EQP may be directly applied to the latch control input of the latch circuit 56. Also, the latch circuit 56
In addition, not only the output count data of the counter 42 but also the output data “± d” of the error calculation circuit 51 may be latched as shown by a broken line in FIG. In that case,
Since the output timing of the output data of the error calculation circuit 51 corresponding to the generation timing of the coincidence detection pulse EQP is slightly delayed due to the circuit operation delay of the latch circuits 49 and 50 and the error calculation circuit 51, an appropriate After performing the time delay adjustment, the output of the error calculation circuit 51 may be latched in the latch circuit 56. When the detection circuit section 41 is configured in consideration of only the dynamic characteristics, FIG.
It will be understood that the circuit 51 and selector 55 of zero and one of the latch circuits 49 or 50 of FIG. 1 may be omitted.

FIG. 11 shows another embodiment of a phase difference detection calculation method capable of canceling the phase fluctuation error "± d". The resolver-type first and second AC output signals A and B output from the secondary coils 21 to 24 of the coil unit 2 are input to the detection circuit unit 60, and the first and second AC output signals A and B are input to the detection circuit unit 60 as in the example of FIG. AC output signal A = sin θ · sin ωt is input to the phase shift circuit 44, and its electric phase is phase-shifted by a predetermined amount, and the phase-shifted AC signal A ′ = sin θ · co
sωt is obtained. In the subtraction circuit 46, the phase-shifted AC signal A ′ = sin θ · cos ωt and the second
Is subtracted from the AC output signal B = cos θ · sin ωt, and as a subtraction output, BA ′ = cos θ · sin ωt−sin θ · cos
As a result, an electrical AC signal Y2 can be obtained, which can be expressed by a simplified expression ωt = sin (ωt−θ). The output signal Y2 of the subtraction circuit 46 is input to the zero-cross detection circuit 48, and a latch pulse LP2 is output in response to the zero-cross detection, and is input to the latch circuit 50.

The embodiment of FIG. 11 differs from the embodiment of FIG. 8 in that the phase shift θ is measured from an AC signal Y2 = sin (ωt−θ) including an electrical phase shift corresponding to the detection target. The difference is that the reference phase is different. In the example of FIG. 8, the reference phase when measuring the phase shift amount θ is the zero phase of the reference sine signal sinωt.
Is not input to the coil section 2 of FIG. 1, and does not include a phase fluctuation error “± d” based on a coil impedance change due to a temperature change or other various factors. Therefore, in the example of FIG. 8, two AC signals Y1 =
sin (ωt + θ) and Y2 = sin (ωt−θ),
By calculating the electrical phase difference, the phase fluctuation error “± d” is canceled. On the other hand, in the embodiment of FIG. 11, a reference phase for measuring the phase shift amount θ is formed based on the first and second AC output signals A and B output from the coil unit 2. The reference phase itself includes the phase variation error “± d”, thereby eliminating the phase variation error “± d”.

That is, in the detection circuit section 60, the first and second AC output signals A and B output from the coil section 2 are input to zero cross detection circuits 61 and 62, respectively, and the respective zero crosses are detected. . The zero-cross detection circuits 61 and 62 respond to either a zero-cross where the amplitude values of the input signals A and B change from negative to positive (so-called 0 phase) or a zero-cross where the amplitude value changes from positive to negative (so-called 180 degree phase). Output a zero-cross detection pulse. This is because sinθ and cosθ, which determine the positive and negative polarities of the amplitudes of the signals A and B, are arbitrarily positive or negative according to the value of θ. This is because it is necessary to detect a zero cross every 180 degrees. Both zero cross detection circuits 61,
The zero-crossing detection pulse output from the OR circuit 62
3 or the output of the OR circuit 63 is
The pulse is input to a divide-by-2 pulse circuit 64 (including, for example, a 分 -divider circuit such as a T-flip-flop and a pulse output AND gate). , A zero-crossing detection pulse corresponding to only the zero phase is output as the reference phase signal pulse RP. This reference phase signal pulse R
P is provided to the reset input of counter 65. The counter 65 constantly counts a predetermined clock pulse CK, and its count value is repeatedly reset to 0 in accordance with the reference phase signal pulse RP. The output of the counter 65 is input to the latch circuit 50, and the count value is latched by the latch circuit 50 at the generation timing of the latch pulse LP2. The data D latched by the latch circuit 50 is output as measurement data of the phase difference θ corresponding to the detection target position x.

The first and second AC output signals A and B output from the coil unit 2 are A = sin θ · sin ω, respectively.
t, B = cos θ · sin ωt, and the electric phases are in phase. Therefore, a zero cross should be detected at the same timing, but since the amplitude coefficient fluctuates with the sine function sin θ and the cosine function cos θ, either amplitude level may be 0 or close to 0, and such In one case, virtually no zero crossing can be detected. Therefore, in this embodiment, zero-cross detection processing is performed for each of the two AC output signals A = sin θ · sin ωt and B = cos θ · sin ωt, and either of the zero-cross detection outputs is OR-combined, so that one of the amplitude levels is obtained. It is characterized in that even if the zero-cross detection cannot be performed due to a small amplitude, the other zero-cross detection output signal having the larger amplitude level can be used.

In the case of the example of FIG. 11, the phase fluctuation error due to the coil impedance change of the coil section 2 is, for example, "-
d ", the AC signal Y2 output from the subtraction circuit 46 becomes Y2 = sin, as shown in FIG.
(Ωt−d−θ). In this case, the output signals A and B of the coil unit 2 have amplitude values sinθ and cosθ corresponding to the angle θ, respectively, and A = sin as illustrated in FIG.
The phase variation error is included, such as θ · sin (ωt−d) and B = cos θ · sin (ωt−d). Therefore, the reference phase signal pulse RP obtained at the timing shown in FIG. 12C based on the zero-cross detection is obtained by calculating the phase variation error −d from the zero phase of the original reference sine signal sinωt.
It is shifted only. Accordingly, based on the reference phase signal pulse RP, the output AC signal Y2
By measuring the phase shift amount of = sin (ωt−d−θ), an accurate value θ from which the phase fluctuation error −d is removed can be obtained.

When the apparatus conditions such as the wiring length of the coil section 2 are determined, the impedance change mainly depends on the temperature. Then, the phase variation error ± d is
This corresponds to data indicating the temperature of the surrounding environment in which the inclination detecting device is provided. Therefore, in the circuit having the circuit 51 for calculating the phase variation error ± d as in the embodiment of FIG. 9, the data of the phase variation error ± d obtained therefrom can be appropriately output as the temperature detection data. Therefore, according to such a configuration of the present invention, not only the inclination of the detection target can be detected by one inclination detection device, but also data indicating the temperature of the surrounding environment of the inclination detection device can be obtained. It has an excellent effect of being able to do so. Of course, without being affected by the impedance change on the sensor side due to temperature change or the length of the wiring cable,
High-precision detection in response to the tilt of the detection target is possible,
This is also an excellent effect. In addition, the examples of FIGS. 8 and 10 are methods for measuring the phase difference in the AC signal, and thus can perform detection with excellent high-speed response compared to the detection method as shown in FIG. It has excellent effects.

In each of the above embodiments, the coil unit 2
And the principle of detection by the magnetic response member 3 may be constituted by a known phase shift type position detection principle. For example,
In the coil unit 2 shown in FIG. 2, the relationship between the primary coil and the secondary coil is reversed, and the sine-phase coil 21 and the minus-sine-phase coil 23 are inverted by sine signals sinωt and −sinωt that are opposite to each other. The coil 22 of the cosine phase and the coil 24 of the negative cosine phase are excited by the cosine signals cosωt and −cosωt having phases opposite to each other, and the outputs including the electric phase shift θ corresponding to the inclination to be detected from the coils 11 to 14. The signal sin (ωt−
θ) may be obtained. Also, as described above, the detection principle by the coil unit 2 and the magnetic response member 3 may be configured to obtain an analog detection output based on a known differential transformer type position detection principle.

Alternatively, in each of the above embodiments, the configuration of the coil unit 2 is not configured to include a pair of a primary coil and a secondary coil, but is configured by only one coil.
The tilt detection data is obtained by driving the one coil at a constant voltage by a predetermined AC signal and measuring a current change based on an inductance change generated according to an amount of a magnetic body (magnetic responsive member 3) penetrating into the coil. It may be obtained. In that case, the required measurement should be performed by a method of measuring an amplitude change of an output signal responsive to the current change, or a method of measuring a phase change between output signals at each end of the coil responsive to the current change. Can be. In each of the above embodiments, the output format of the detection data is not limited to digital absolute data or analog voltage data, but may be incremental pulse data or a repetitive pulse signal obtained by frequency-converting an absolute value.
The format may be appropriate according to the purpose of use.

[0046]

As described above, according to the present invention, according to the present invention, the storage body including the downwardly curved passage, the magnetic responsive member housed movably according to gravity in the passage, and the storage body An induction output signal for detecting a position of the magnetic responsive member in the passage, wherein the magnetic responsive member is displaced along the passage in accordance with the inclination of the housing, and a coil portion provided on an outer periphery of the passage. Is obtained from the coil part, the inclination is detected. Therefore, when the storage body is in the horizontal position, the magnetic responsive member in the passage always has a predetermined position (corresponding to the inclination 0) due to its own weight. When the storage body is tilted, the magnetic responsive member is displaced along the passage accordingly, and an induction output signal for detecting the position of the magnetic responsive member in the passage is output from the coil unit. can get And than can perform tilt detection without contact, is excellent in durability and environmental resistance, it is possible to provide a non-conventional useful inclinometer.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an inclinometer according to the present invention.

FIG. 2 is a circuit diagram showing a configuration example of a coil unit in FIG. 1;

FIG. 3 is a diagram showing a modification of the magnetic response member in FIG. 1;

FIG. 4 is a schematic external view showing another embodiment of the inclinometer according to the present invention.

FIG. 5 is a schematic diagram showing an example in which two inclinometers shown in FIG. 1 are combined in an orthogonal relationship to detect tilt in two axial directions.

FIG. 6 is a schematic view showing another example of detecting two-axis tilt by combining two inclinometers according to the present invention in an orthogonal relationship.

FIG. 7 is a block diagram showing an example of a phase detection type measurement circuit applicable to the inclinometer according to the present invention.

FIG. 8 is a block diagram showing another example of a phase detection type measurement circuit applicable to the inclinometer according to the present invention.

FIG. 9 is an operation explanatory diagram of FIG. 8;

FIG. 10 is a block diagram showing a modification example added to the circuit of FIG. 8;

FIG. 11 is a block diagram showing still another example of a phase detection type measurement circuit applicable to the tilt detection device according to the present invention.

FIG. 12 is an operation explanatory diagram of FIG. 11;

[Explanation of symbols]

 10, 10X, 10Y, 10X ', 10Y' Inclinometer 1 Housing 1a Passage 2 Coil section 11 to 15 Primary coil 21 to 24 Secondary coil 3 Magnetic response member 40 Digital phase detection circuit

Continued on the front page (72) Inventor Nobuyuki Akazu 2-1453-43, Niibori, Higashiyamato-shi, Tokyo (72) Inventor Kazuya Sakamoto 1-1-5 Kawasaki, Hamura-shi, Tokyo, MAC Hamura Court II-405 (72 ) Inventor Hiroshi Sakamoto 896-8 Yamada, Kawagoe-shi, Saitama (72) Inventor Akio Yamamoto 1-13-29 Nishi, Kunitachi-shi, Tokyo KM Heights 101

Claims (5)

[Claims] 1. A housing including a passage curved downward, a magnetic responsive member housed movably according to gravity in the passage, and a coil portion provided on an outer periphery of the passage in the housing. The magnetic responsive member is displaced along the passage in accordance with the inclination of the storage body, and an inductive output signal for detecting a position of the magnetic responsive member in the passage is obtained from the coil unit, whereby the inclination is obtained. An inclinometer characterized by detecting 2. The inclinometer according to claim 1, wherein the coil unit is provided with a plurality of coils along the passage. 3. The coil unit is excited by a one-phase AC signal, and according to a relative position of the magnetic response member,
3. The inclinometer according to claim 1, wherein the inclinometer outputs a two-phase output AC signal of an output AC signal indicating an amplitude function characteristic of a sine phase and an output AC signal indicating an amplitude function characteristic of a cosine phase. 4. The passage according to claim 1, wherein the passage is a pipe-like passage, and the magnetic response member is made of a predetermined amount of a magnetic fluid or a powder stored in the pipe. The inclinometer described. 5. An inclinometer according to any one of claims 1 to 4, wherein at least two inclinometers are arranged in directions different from each other,
An inclinometer for detecting inclination in at least two directions.