CN105738944A - Inclinedly suspended seismometer, coordinate transformation circuit thereof and transformation method of coordinate transformation circuit - Google Patents

Abstract

The present invention discloses an inclinedly suspended seismometer, a coordinate transformation circuit thereof and a transformation method of the coordinate transformation circuit. The sensing directions of the inclinedly suspended seismometer form a UVW coordinate system, and the seismometer comprises three swinging bodies annularly and evenly arranged on a reference bottom plate, a main control chip, an angle sensor and the coordinate transformation circuit. The angle sensor acquires an inclination angle signal of the seismometer, the main control chip performs processing according to the inclination angle signal to obtain a transformation coefficient matrix and the transformation parameters of the coordinate transformation circuit, and the coordinate transformation circuit transforms the signals in the U,V and W three directions into the signals in the X, Y and Z directions according to the transformation parameters. According to the present invention, the transformation parameters of the coordinate transformation circuit are correspondingly adjusted according to the inclination angle of the seismometer, thereby realizing the accurate measurement of the seismometer.

Description

Inclined suspension seismometer and coordinate transformation circuit and transformation method thereof

Technical Field

The invention relates to a coordinate transformation method of a seismometer, in particular to an obliquely suspended seismometer and a coordinate transformation circuit and a coordinate transformation method thereof.

Background

Three pendulums of the oblique suspension seismometer are arranged on the same reference surface and are uniformly arranged along the circumference at an angle of 120 degrees, namely, the pendulums are orthogonally arranged along U, V, W directions, ground vibration signals collected by the three pendulums are processed by a coordinate conversion circuit and a signal processing circuit, and analog voltage signals of X, Y, Z directions are output in three directions of east-west direction, south-north direction and vertical direction.

The existing coordinate transformation circuit can convert U, V, W-divided signals which are sensed by a seismometer placed on a horizontal plane and are orthogonal to each other into X, Y, Z-divided signals, when the seismometer is placed in an inclined mode, zero setting operation needs to be carried out on a pendulum body in the corresponding direction to guarantee the normal working state of the seismometer, the orthogonality of U, V, W-divided directions is damaged, and therefore signals output by the coordinate transformation circuit are inaccurate.

Disclosure of Invention

In view of the above, it is an object of the present invention to provide an obliquely suspended seismometer and a coordinate transformation circuit and transformation method thereof, which can achieve accurate measurement of the seismometer regardless of whether the seismometer is tilted or horizontally placed.

In order to achieve the purpose, the invention adopts the following technical scheme:

an inclined suspension seismometer comprises three pendulums which are uniformly arranged on a reference bottom plate along 120 degrees, a main control chip, an angle sensor and a coordinate transformation circuit,

the angle sensor collects inclination angle signals of the seismometer, the main control chip processes the inclination angle signals to obtain a transformation coefficient matrix of the coordinate transformation circuit to obtain transformation parameters of the coordinate transformation circuit, and the coordinate transformation circuit converts signals in U, V, W three directions of the sensing direction of the obliquely suspended seismometer into signals in X, Y, Z directions according to the transformation parameters.

Further, in the above-mentioned case,

the inclination angle comprises an inclination angle of a Z axis, and an included angle between the projection of the inclined Z axis on the XOY plane and the Y axis.

The coordinate transformation circuit comprises three groups of nine DACs with an R-2R structure, and the three groups of DACs are used for converting U, V, W branch signals into X-branch signals, Y-branch signals and Z-branch signals respectively.

The angle sensor is mounted on the reference base plate.

And three groups of transformation units for converting the U, V, W-division signals into X-division signals, Y-division signals and Z-division signals, wherein transformation parameters of the three groups of transformation units are adjusted according to the inclination angle of the seismometer.

The inclination angle comprises an inclination angle theta of a Z axis, and an included angle between the projection of the inclined Z axis on the XOY plane and the Y axis

The coordinate transformation relation of the coordinate transformation circuit is as follows:

$\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)={\left(\begin{array}{ccc}{T}_{11}& T_{12}& T_{13}\\ T_{21}& T_{22}& T_{23}\\ T_{31}& T_{32}& T_{33}\end{array}\right)}^{-1}\left(\begin{array}{c}U\\ V\\ W\end{array}\right)=T^{-1}\left(\begin{array}{c}U\\ V\\ W\end{array}\right)---\left(1\right)$

wherein,

wherein α is the inclination angle of pendulum suspension, α_U、α_V、α_Wα at U, V, W deg. angles to horizontal plane, β_Uβ is the rotation angle of the pendulum body around the Y axis and is clockwise positive_VFor swinging body around V_HRotation angle of the shaft, clockwise positive β_WFor swinging body around W_HThe rotation angle of the shaft is positive clockwise; v_HThe axis being the projection of the V component onto the XOY plane, W_HThe axis is the projection of the W direction on the XOY plane;

the transformation parameters of the transformation unit are adjusted according to formula (2).

Each group of conversion units comprises three DACs of an R-2R structure, a first group of three DACs are used for converting differential signals of UVW direction into signals of X direction, a second group of three DACs are used for converting differential signals of UVW direction into signals of Y direction, and a third group of three DACs are used for converting differential signals of UVW direction into signals of Z direction.

The transfer function of the transformation unit is:

$X=\frac{R_F}{2R}(U\·\frac{D_{u1}-2^{N-1}}{2^{N-1}}+V\·\frac{D_{v1}-2^{N-1}}{2^{N-1}}+W\·\frac{D_{w1}-2^{N-1}}{2^{N-1}})---\left(6\right)$

$Y=\frac{R_F}{2R}(U\·\frac{D_{u2}-2^{N-1}}{2^{N-1}}+V\·\frac{D_{v2}-2^{N-1}}{2^{N-1}}+W\·\frac{D_{w2}-2^{N-1}}{2^{N-1}})---\left(7\right)$

$Z=\frac{R_F}{2R}(U\·\frac{D_{u3}-2^{N-1}}{2^{N-1}}+V\·\frac{D_{v3}-2^{N-1}}{2^{N-1}}+W\·\frac{D_{w3}-2^{N-1}}{2^{N-1}})---\left(8\right)$

and determining the transformation parameters of the transformation unit according to the transfer function and the formula (2).

And adjusting the transformation parameters of the coordinate transformation circuit according to an inclination angle, wherein the coordinate transformation circuit converts the U, V, W branch signals into X, Y, Z branch signals according to the transformation parameters.

The invention has the advantages that:

the seismometer and the coordinate transformation circuit and the transformation method thereof utilize the angle sensor to measure the inclination angle of the seismometer, obtain the transformation coefficient matrix of the coordinate transformation circuit on the basis, and adjust the transformation parameters of the coordinate transformation circuit according to the transformation coefficient matrix, thereby realizing the accuracy of the measured data when the seismometer is placed in an inclined state.

Drawings

FIG. 1 is a schematic diagram of the electrical circuit configuration of the tilt suspension seismometer of the present invention.

FIG. 2A is a schematic diagram of the relationship between pendulum bob and XYZ-axis of a tilt-suspension seismometer.

Fig. 2B is a schematic view of the projection of UVW onto XOY plane.

Fig. 3A is a schematic position diagram before the pendulum zero setting operation.

Fig. 3B is a schematic diagram of the pendulum after the zeroing operation.

Fig. 4A is a schematic view of X, Z rotation about the Y-axis.

Fig. 4B is a schematic view of the projection of the U direction onto the X axis in the rotated coordinate system shown in fig. 4A.

FIG. 5 is a schematic representation of the coordinate system after the seismometer has been tilted.

β in FIGS. 5A and 5B_V、β_WThe position of the corner in the coordinate system shown in fig. 5 is schematically shown.

Fig. 6 is a schematic diagram of a part of the structure of the coordinate transformation circuit of the present invention, showing the circuit structure of a set of three DACs.

Detailed Description

The present invention will be described in further detail with reference to the following drawings and examples.

The invention discloses an inclined suspension seismometer which comprises a sealed shell, three pendulums and a circuit board, wherein the three pendulums are arranged in the shell, the three pendulums are uniformly arranged on a reference bottom plate along 120 degrees, the structures of the three pendulums are the same, the three pendulums are all mechanical pendulums with inclined suspension inverted pendulum structures, an angle sensor is arranged on the reference bottom plate, the reference bottom plate needs to be adjusted to be horizontal before the angle sensor is arranged, and meanwhile, the horizontal installation position of the angle sensor needs to be aligned with the X, Y direction.

As shown in fig. 1, the circuit board is provided with a main control chip, a coordinate transformation circuit, three oscillation and feedback circuits corresponding to three pendulums, and the like, a signal output end of the angle sensor is connected with a data input end of the main control chip, the coordinate transformation circuit is connected with an I/O end of the main control chip, U, V, W three divided pendulums are respectively connected with the coordinate transformation circuit through corresponding oscillation and feedback circuits, U, V, W three divided oscillation and feedback circuits are used for converting ground motion sensed by the corresponding divided pendulums into analog voltage signals of corresponding division, and U, V, W three divided analog voltage signals are processed by the coordinate transformation circuit and then output analog voltage signals of X, Y, Z division.

The angle sensor transmits the sensed seismometer inclination angle signal to the main control chip, the main control chip calculates a transformation coefficient matrix of the coordinate transformation circuit according to the inclination angle signal, transformation parameters of the coordinate transformation circuit are set according to the transformation coefficient matrix, and the coordinate transformation circuit converts U, V, W three-direction analog voltage signals into X, Y, Z-direction analog voltage signals according to the set transformation parameters.

The operation principle of the coordinate conversion circuit and the coordinate conversion method according to the present invention will be described in detail below.

1) Horizontal placement state of seismometer

As shown in fig. 2A and 2B, if α is the tilt angle of the pendulum suspension, i.e. the angle between the pendulum and the Z axis is α, the U, V, W direction is expressed in the X, Y, Z coordinate system as:

$\left(\begin{array}{c}U\\ V\\ W\end{array}\right)=\left(\begin{array}{ccc}0& {\mathrm{cos\α}}_U& {\mathrm{sin\α}}_U\\ {\mathrm{cos\α}}_{V}cos30& -{\mathrm{cos\α}}_{V}cos60& {\mathrm{sin\α}}_V\\ -{\mathrm{cos\α}}_{W}cos30& -{\mathrm{cos\α}}_{W}cos60& {\mathrm{sin\α}}_W\end{array}\right)\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)---\left(1\right)$

α therein_U、α_V、α_WThe components of the angle α in the U, V, W direction are respectively obtained after inverse transformation of the formula (1):

$\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)={\left(\begin{array}{ccc}0& {\mathrm{cos\α}}_U& {\mathrm{sin\α}}_U\\ {\mathrm{cos\α}}_{V}cos30& -{\mathrm{cos\α}}_{V}cos60& {\mathrm{sin\α}}_V\\ -{\mathrm{cos\α}}_{W}cos30& -{\mathrm{cos\α}}_{W}cos60& {\mathrm{sin\α}}_W\end{array}\right)}^{-1}\left(\begin{array}{c}U\\ V\\ W\end{array}\right)---\left(2\right)$

if it isα_U＝α_V＝α_W35.26 °, a transformation coefficient matrix of the coordinate transformation circuit is obtained:

$\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)=\left(\begin{array}{ccc}0& \frac{1}{\sqrt{2}}& -\frac{1}{\sqrt{2}}\\ \frac{2}{\sqrt{6}}& -\frac{1}{\sqrt{6}}& -\frac{1}{\sqrt{6}}\\ \frac{1}{\sqrt{3}}& \frac{1}{\sqrt{3}}& \frac{1}{\sqrt{3}}\end{array}\right)\left(\begin{array}{c}U\\ V\\ W\end{array}\right)---\left(3\right)$

2) seismometer inclined placement state

As the sensing direction (U, V, W direction) of the pendulum body inclines, zero adjustment and correction operation are required to be carried out on the pendulum body, so that the seismometer is in a normal working state, as shown in figures 3A and 3B, before zero adjustment, the rotation angle delta α of the pendulum body is changed into_UI.e. Y, Z axis rotated about the X axis by an angle of delta α_UI.e. α_UBecome α_U+Δα_UAfter zeroing correction, Δ α_U＝0；

As shown in FIGS. 4A and 4B, for lateral tilt of the pendulum (seismometer global tilt), the X, Z axis is rotated β about the Y axis_UThe angle, the projection of the U component onto the Y axis, is constant and is Ucos α_UThe projection of the U direction on the Z axis is Usin α_UU＝sinα_Ucosβ_U(ii) a The projection of the U direction on the X axis becomes:

0＝-Usinα_Usinβ_U；

as shown in fig. 5, 5A, 5B, setting β_Uβ is the rotation angle of the pendulum body around the Y axis, clockwise is positive_VFor swinging body around V_HRotation angle of the axis (projection of the V direction onto the XOY plane), clockwise, is positive β_WFor swinging body around W_HThe rotation angle of the axis (W direction projection on XOY plane) is positive clockwise, theta is the inclination angle of the Z 'axis, namely the included angle between the Z axis and the Z' axis,the azimuth angle of the Z 'axis relative to the inclination direction of the Y axis, i.e. the included angle between the projection of the Z' axis on the XOY plane and the Y axis, can be obtained:

in the tilted state, the resulting U, V, W orientation is expressed in the X, Y, Z coordinate system as:

$\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)={\left(\begin{array}{ccc}{T}_{11}& T_{12}& T_{13}\\ T_{21}& T_{22}& T_{23}\\ T_{31}& T_{32}& T_{33}\end{array}\right)}^{-1}\left(\begin{array}{c}U\\ V\\ W\end{array}\right)=T^{-1}\left(\begin{array}{c}U\\ V\\ W\end{array}\right)---\left(7\right)$

wherein:

the balancing effect of gravity changes due to lateral tilt, taking the U-direction pendulum body as an example, the component of gravity in the sensing direction due to the pendulum is given by gsin α_UBecomes gsin α_Ucosβ_UThe balance angle of the pendulum changes accordingly to balance the change in the component of gravity in the sensing direction when α_U＝35.26°、β_U5 deg. and consists of gsin (α)_U+_U)＝gsinα_Ucosβ_UCan obtain the product_UThe angle value is negligible at-0.154 °.

Using an angle sensor to acquire two-direction inclination angle signals, i.e. the sum of theta angles acquired by the angle sensorThe angle signal is transmitted to a main control chip, and the main control chip is used for collecting the sum of the theta anglesAngle signals, respectively calculating T in the formula (8)₁₁-T₃₃To obtain the coordinate transformation matrix T in the formula (7)^-1。

As shown in fig. 6, the coordinate transformation circuit disclosed by the invention comprises three groups of nine DACs with an R-2R structure, wherein the first group of three DACs are used for converting differential signals of UVW direction into signals of X direction, the second group of three DACs are used for converting differential signals of UVW direction into signals of Y direction, and the third group of three DACs are used for converting differential signals of UVW direction into signals of Z direction. In particular, the present invention relates to a method for producing,

transfer function according to seismometer:

$X=\frac{R_F}{2R}(U\·\frac{D_{u1}-2^{N-1}}{2^{N-1}}+V\·\frac{D_{v1}-2^{N-1}}{2^{N-1}}+W\·\frac{D_{w1}-2^{N-1}}{2^{N-1}})---\left(9\right)$

$Y=\frac{R_F}{2R}(U\·\frac{D_{u2}-2^{N-1}}{2^{N-1}}+V\·\frac{D_{v2}-2^{N-1}}{2^{N-1}}+W\·\frac{D_{w2}-2^{N-1}}{2^{N-1}})---\left(10\right)$

$Z=\frac{R_F}{2R}(U\·\frac{D_{u3}-2^{N-1}}{2^{N-1}}+V\·\frac{D_{v3}-2^{N-1}}{2^{N-1}}+W\·\frac{D_{w3}-2^{N-1}}{2^{N-1}})---\left(11\right)$

in conjunction with equation (7), we obtain:

$\begin{array}{c}{T}_{11}=\frac{R_F}{2R}\·\frac{D_{u1}-2^{N-1}}{2^{N-1}}\\ T_{12}=\frac{R_F}{2R}\·\frac{D_{v1}-2^{N-1}}{2^{N-1}}\\ T_{13}=\frac{R_F}{2R}\·\frac{D_{w1}-2^{N-1}}{2^{N-1}}\end{array}---\left(12\right)$

$\begin{array}{c}{T}_{21}=\frac{R_F}{2R}\·\frac{D_{u2}-2^{N-1}}{2^{N-1}}\\ T_{22}=\frac{R_F}{2R}\·\frac{D_{v2}-2^{N-1}}{2^{N-1}}\\ T_{23}=\frac{R_F}{2R}\·\frac{D_{w2}-2^{N-1}}{2^{N-1}}\end{array}---\left(13\right)$

$\begin{array}{c}{T}_{31}=\frac{R_F}{2R}\·\frac{D_{u3}-2^{N-1}}{2^{N-1}}\\ T_{32}=\frac{R_F}{2R}\·\frac{D_{v3}-2^{N-1}}{2^{N-1}}\\ T_{33}=\frac{R_F}{2R}\·\frac{D_{w3}-2^{N-1}}{2^{N-1}}\end{array}---\left(14\right)$

wherein R is_FIs the feedback resistance of the negative input terminal of the operational amplifier.

According to the formulas (8), (12) to (14), the main control chip utilizes the theta angle sum acquired by the angle sensorAngle signal, calculating to obtain transformation coefficient matrix of coordinate transformation circuit, and further calculating to obtain transformation parameter D_u1、D_v1、D_w1、D_u2、D_v2、D_w2、D_u3、D_v2、D_w3The conversion parameters are output to a coordinate conversion circuit through the DAC, and the coordinate conversion circuit converts U, V, W voltage signals in three directions into corresponding X, Y, Z voltage signals in directions according to the conversion parameters.

The invention relates to an inclined suspension seismometer and a coordinate transformation circuit and a transformation method thereof.A transformation coefficient matrix of the coordinate transformation circuit is obtained by calculation on the basis of measuring the inclined angles of the seismometer in two directions by utilizing an angle sensor, and then transformation parameters of the coordinate transformation circuit are obtained by calculation, so that the coordinate transformation circuit can correspondingly adjust the transformation parameters according to the inclined angles of the seismometer, and the accurate measurement of the seismometer in an inclined state can be realized.

The above description is of the preferred embodiment of the present invention and the technical principles applied thereto, and it will be apparent to those skilled in the art that any changes and modifications based on the equivalent changes and simple substitutions of the technical solution of the present invention are within the protection scope of the present invention without departing from the spirit and scope of the present invention.

Claims (10)

1. The obliquely suspended seismometer comprises three pendulums which are uniformly arranged on a reference bottom plate along 120 degrees, and is characterized by also comprising a main control chip, an angle sensor and a coordinate conversion circuit,

the angle sensor collects inclination angle signals of the seismometer, the main control chip processes the inclination angle signals to obtain a transformation coefficient matrix of the coordinate transformation circuit to obtain transformation parameters of the coordinate transformation circuit, and the coordinate transformation circuit converts signals in U, V, W three directions of the sensing direction of the obliquely suspended seismometer into signals in X, Y, Z directions according to the transformation parameters.

2. The tilt suspension seismometer of claim 1, wherein the tilt angle comprises a tilt angle of the Z-axis, and an angle between a projection of the tilted Z-axis on the XOY plane and the Y-axis.

3. The tilt suspension seismometer of claim 1, wherein the coordinate transformation circuit comprises three sets of nine DACs of R-2R configuration, the three sets of DACs being configured to convert U, V, W signals into X-, Y-and Z-signals, respectively.

4. The tilt suspension seismometer of claim 1, wherein the angle sensor is mounted on the reference baseplate.

5. A coordinate conversion circuit of a tilt suspension seismometer is characterized by three groups of conversion units for converting U, V, W direction signals into X direction signals, Y direction signals and Z direction signals, and conversion parameters of the three groups of conversion units are adjusted according to the tilt angle of the seismometer.

6. The tilt suspension seismometer of claim 5, wherein the tilt angles comprise a tilt angle θ of the Z axis, and an included angle between a projection of the tilted Z axis on the XOY plane and the Y axis

7. The coordinate transformation circuit of a canted suspension seismometer according to claim 6, wherein the coordinate transformation circuit has a coordinate transformation relationship of:

$\left(\begin{array}{c}X\\ Y\\ Z\end{array}\right)={\left(\begin{array}{ccc}{T}_{11}& T_{12}& T_{13}\\ T_{21}& T_{22}& T_{23}\\ T_{31}& T_{32}& T_{33}\end{array}\right)}^{-1}\left(\begin{array}{c}U\\ V\\ W\end{array}\right)=T^{-1}\left(\begin{array}{c}U\\ V\\ W\end{array}\right)---\left(1\right)$

wherein,

wherein α is the inclination angle of pendulum suspension, α_U、α_V、α_Wα at U, V, W deg. angles to horizontal plane, β_Uβ is the rotation angle of the pendulum body around the Y axis and is clockwise positive_VFor swinging body around V_HRotation angle of the shaft, clockwise positive β_WFor swinging body around W_HThe rotation angle of the shaft is positive clockwise; v_HThe axis being the projection of the V component onto the XOY plane, W_HThe axis is the projection of the W direction on the XOY plane;

the transformation parameters of the transformation unit are adjusted according to formula (2).

8. The coordinate transformation circuit of the oblique suspension seismometer of claim 7, wherein each group of transformation units comprises three DACs of R-2R structure, the first group of three DACs is used for converting differential signals of UVW direction into signals of X direction, the second group of three DACs is used for converting differential signals of UVW direction into signals of Y direction, and the third group of three DACs is used for converting differential signals of UVW direction into signals of Z direction.

9. The coordinate transformation circuit of a canted suspension seismometer of claim 8, wherein the transfer function of the transformation unit is:

$X=\frac{R_F}{2R}(U\·\frac{D_{u1}-2^{N-1}}{2^{N-1}}+V\·\frac{D_{v1}-2^{N-1}}{2^{N-1}}+W\·\frac{D_{w1}-2^{N-1}}{2^{N-1}})---\left(6\right)$

$Y=\frac{R_F}{2R}(U\·\frac{D_{u2}-2^{N-1}}{2^{N-1}}+V\·\frac{D_{v2}-2^{N-1}}{2^{N-1}}+W\·\frac{D_{w2}-2^{N-1}}{2^{N-1}})---\left(7\right)$

$Z=\frac{R_F}{2R}(U\·\frac{D_{u3}-2^{N-1}}{2^{N-1}}+V\·\frac{D_{v3}-2^{N-1}}{2^{N-1}}+W\·\frac{D_{w3}-2^{N-1}}{2^{N-1}})---\left(8\right)$

and determining the transformation parameters of the transformation unit according to the transfer function and the formula (2).

10. A method for converting a coordinate conversion circuit of an inclined suspension seismometer, characterized in that a conversion parameter of the coordinate conversion circuit is adjusted according to an inclination angle, and the coordinate conversion circuit converts an U, V, W branch signal into a X, Y, Z branch signal according to the conversion parameter.