JP4629895B2 - Gyrocompass device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gyrocompass device for detecting the position of an object or a moving body that is difficult for humans to approach, such as an object under the ground or underwater, and in particular, a relatively small diameter pipe such as a sewer pipe. The present invention relates to a gyrocompass apparatus and method suitable for use in laying by a propulsion method.
[0002]
[Prior art]
When a pipe having a relatively small diameter, such as a sewage pipe, is laid underground, a propulsion method is known in which pipes are placed simultaneously while digging underground. This method excavates a vertical hole in the ground at the start and end points of the pipe, but there is an advantage such as not obstructing traffic because there is no need to dig up the ground along the pipe.
[0003]
With reference to FIG. 9, the example of a propulsion construction method and the excavator used for it is demonstrated. This excavating apparatus includes a leading conduit 202 having an excavating blade 201 at the tip, a guide member 203 attached to the rear end of the leading conduit 202, a large number of connected fume tubes 210A, 210B, 210C, and 210D, and a pushing device. 220. The main pushing device 220 is disposed in a vertical hole at the starting point of the pipe. A mud material supply pipe 205, a sediment discharge pipe 206, and a sediment discharge pump 207 are arranged in the fume pipe.
[0004]
When excavating the horizontal hole with the excavating blade, a mud material such as water is ejected from the mud material supply pipe 205 to the tip of the excavating blade 201. The excavated earth and sand are separated into water-stopping earth and fluid sand (slurry), and the fluid earth and sand are pumped up by the earth and sand discharge pump 207 and discharged to the outside through the earth and sand discharge pipe 206.
[0005]
FIG. 9A shows a state in which the fume tube rows 210A, 210B, 210C, and 210D are disposed behind the leading conduit 202 by digging to a predetermined position. At the start of excavation, only the leading conduit 202 is disposed in the main pushing device 220. FIG. 9B shows a state in which a state corresponding to the length of one fume tube has been dug from this state. While the fume tube rows 210A, 210B, 210C, 210D are pushed forward by the main pushing device 220, the excavating blade 201 excavates. Thereby, the leading conduit and the entire fume tube row are advanced. Next, as shown in FIG. 9C, the piston of the main pushing device 220 is retracted, and the next fume tube 210E is disposed at the rear end of the rearmost fume tube 210D.
[0006]
This is repeated, and when the tip conduit 202 arrives at the vertical hole at the end point, the tip conduit 202, the mud material supply pipe 205, the earth and sand discharge pipe 206, and the discharge pump 207 are recovered. Thereby, the piping formed by the fume pipe from the start point to the end point is completed.
[0007]
The leading conduit is provided with a gyrocompass device, and the current position is always detected. If the current position deviates from the planned position, the traveling direction is corrected. By changing the direction of excavation, the direction of travel of the leading conduit can be adjusted. Thus, by excavating while adjusting the traveling direction of the leading conduit, accurate piping is laid from the start point to the end point.
[0008]
In recent years, piping is often laid over a relatively long distance by a propulsion method. In such a case, the error at the end point becomes large even with a slight error in the traveling direction. For example, if the digging is performed 100 m in a state where the traveling direction of the leading conduit is deviated once from the planned route, the end point is deviated from the planned route by about 1.74 m. Usually, the error is preferably within several centimeters.
[0009]
[Problems to be solved by the invention]
A gyrocompass device is used to detect the position of an underground or underwater object, such as a drilling device's tip conduit. Various types of gyrocompass devices such as an electromagnetic wave method and a gyroscope are used, but there is no small size, small diameter, high accuracy, and low price. In particular, a small and small-diameter gyrocompass device that can be used in an environment of vibration, high temperature, and high humidity has a drawback of high cost.
[0010]
An object of the present invention is to provide a gyrocompass device that is small and has a small diameter, high measurement accuracy, and low price.
[0011]
[Means for Solving the Problems]
According to the present invention, a gyrocompass device includes a cylindrical casing having a central axis, a base disposed in the casing, and a sensor including an XYZ gyro, an XYZ accelerometer, and an azimuth transmitter mounted on the base. In the compass mode, a calculation unit that converts the signal output from the sensor unit into a signal of the earth surface coordinate system, and in the surveying mode, the orientation of the base, the gyro drift and the signal output from the sensor unit A drift / bias calculation unit for calculating an acceleration bias, and the base includes a plurality of turntables arranged along the central axis and a drive device for synchronously rotating the plurality of turntables The sensor unit is mounted on the turntable so that its input axis or measurement axis is aligned with the central axis.
[0012]
According to the present invention, the XYZ gyro is composed of a TDG (tuned dry gyro).
[0013]
According to the present invention, the calculation unit includes a coordinate conversion matrix calculation unit for calculating a coordinate conversion matrix for converting from a coordinate system provided on the base to an earth surface coordinate system, and an earth surface coordinate system using the coordinate conversion matrix. A local acceleration calculation unit for calculating the acceleration of the earth, and a local azimuth / posture calculation unit for calculating the azimuth and posture of the earth surface coordinate system.
[0014]
According to the present invention, the drift / bias calculation unit includes a rotation control unit that controls the rotation of the turntable, and a data measurement storage unit that stores the outputs of the XYZ gyro and the XYZ accelerometer using the azimuth angle of the turntable as a parameter. And an arithmetic unit for calculating drift and bias of the output of the XYZ gyro and XYZ accelerometer from an output from the data measurement storage unit, and an azimuth arithmetic unit for calculating the azimuth of the base, The bias and drift of the sensor unit are detected from the output of the sensor unit at the rotation angle.
[0015]
According to the present invention, the outer diameter of the cylindrical casing is 80 mm or less.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An example of the gyrocompass device of the present invention will be described with reference to FIGS. The gyrocompass apparatus of this example includes a casing 50 and a base 10 accommodated in the casing. The casing 50 includes a cylindrical portion 51 and disc portions 52 at both ends. According to this example, the outer diameter of the cylindrical portion 51 is at least 80 mm or less, preferably 60 mm or less.
[0017]
A coordinate system is set on the casing 50 or the base 10. An x-axis is taken along the central axis of the cylindrical portion of the casing, a y-axis is parallel to the base 10, and a z-axis is perpendicular to the base 10. Since the coordinates set in this way can be regarded as the coordinates set for the mobile body equipped with the gyrocompass device, these are hereinafter referred to as mobile body coordinates. The reference azimuth of the base 10, that is, the azimuth of the moving body is the positive direction of the x axis. On the other hand, the coordinates provided on the surface of the earth are referred to as local coordinates or local coordinates. A local coordinate is a coordinate system in which a point on the earth surface is an origin, an x axis is in the meridian direction, a y axis is in the latitude direction, and a z axis is vertically upward along the horizontal plane.
[0018]
The gyrocompass device of this example further includes an X accelerometer 11A, a Y accelerometer 12A and a Z accelerometer 13A, an X gyro 11G, a Y gyro 12G and a Z gyro 13G, and an azimuth transmitter 13Y. These constitute the sensor unit of the gyrocompass device. The arrow attached to each sensor indicates the direction of the input axis or the measurement axis.
[0019]
A TDG (tuned dry gyro) may be used as the gyro. The TDG is composed of a gyro having two input axes orthogonal to each other. Therefore, when using TDG, the 1st gyroscope which consists of XY gyros and the 2nd gyroscope which consists of YZ gyros are used. The first gyro is used as the X gyro and the second gyro is used as the Z gyro. As the Y gyro, the first gyro may be used or the second gyro may be used. Here, the first gyro is used.
[0020]
The base 10 is provided with a plurality of turntables. In the example of FIG. 1, two turntables 20A and 20B are provided, the first gyro, ie, the XY gyro, is mounted on the first turntable 20A, and the X and Y accelerometers are the second turntable. It is mounted on 20B. In the example of FIG. 2, three turntables 20C, 20D, and 20E are provided, and the first gyro, ie, the XY gyro, is mounted on the first turntable 20C, and the X accelerometer is on the second turntable 20D. The Y accelerometer is mounted on the third turntable 20E. The direction transmitter 13Y (shown only in FIG. 1 and omitted in FIG. 2) is mounted on at least one of the plurality of turntables.
[0021]
An azimuth servo motor is provided for rotating a plurality of turntables, and a suitable transmission device, such as a backlashless gear transmission or a backlashless belt transmission, for transmitting the rotation of the azimuth servomotor to the plurality of turntables. The device is used. All the turntables rotate synchronously, that is, rotate in the same direction at the same relative angle and at the same rotational speed. Therefore, in order to detect the rotation angle of the turntable, as described above, the azimuth transmitter 13Y has only to be arranged on one turntable and does not need to be mounted on all turntables.
[0022]
  According to this example, the turntable rotates at a rotation speed of ± 180 ° at a constant rotation speed, for example, 10 ° / second. Since the rotation angle of the turntable is limited to ± 180 °, cables or wires from the gyroscope, the accelerometer, and the bearing transmitter attached to the turntable are not twisted. Figure2As shown in FIG. 2, the circuit board constituting the calculation units 2 and 3 is mounted on the base.
[0023]
According to this example, the X, Y and Z accelerometers 11A, 12A, 13A, X, Y and Z gyro 11G, 12G, 13G and the direction transmitter 13Y constituting the sensor unit of the gyro compass device are Arranged on the central axis, that is, on the x-axis or aligned with the x-axis. The rotation axes of the turntables 20A, 20B, 20C, 20D, and 20E are arranged on the x axis.
[0024]
  The outline of the gyrocompass apparatus of this example will be described with reference to FIG. The gyrocompass apparatus includes a sensor unit 1, a calculation unit 2, and a drift / bias calculation unit 3. The configuration of the sensor unit 1 has been described with reference to FIGS. 1 and 2. Here, the input axis or measurement axis (arrow) of each sensor will be described. The X accelerometer 11A and the X gyro 11G are arranged so that their input axes are aligned with the positive direction of the x axis of the moving body coordinate system, and the Y accelerometer 12A and the Y gyro 12G have their input axes aligned with the moving body. It arrange | positions so that it may align with the positive direction of the y-axis of a coordinate system. The Z accelerometer 13A, Z gyro 13G, and azimuth transmitter 13Y have their input axes on the z axis of the moving object coordinate system.negativeIt arrange | positions so that it may align with the direction of.
[0025]
The X accelerometer 11A detects the acceleration in the x-axis direction of the moving body coordinate system, and the X gyro is the angular velocity ω around the x axis of the moving body coordinate system._XIs detected. The Y accelerometer 12A detects the acceleration in the y-axis direction of the moving object coordinate system, and the Y gyro 12G detects the angular velocity ω around the y axis of the moving object coordinate system._YIs detected. The Z accelerometer 13A detects the acceleration in the z-axis direction of the moving object coordinate system, and the Z gyro 13G detects the angular velocity ω around the z axis of the moving object coordinate system._ZIs detected. The direction transmitter 13Y detects the rotation angle φ of the turntable 20 with respect to the direction (x axis) of the moving body.
[0026]
As described above, when the TDG is used as the first and second gyros, the X gyro and the Y gyro are included in the first gyro and the Y gyro and the Z gyro are included in the second gyro, This is illustrated as a separate gyro.
[0027]
The gyrocompass device of this example functions as a strap-down gyrocompass when the moving body is moving, and functions as a surveying compass when the moving body is stationary. That is, the gyro compass device of this example can operate in two modes, a compass mode and a survey mode.
[0028]
The sensor unit of the gyro compass device of this example is directly attached to a moving body whose position is to be measured. The moving body may be, for example, a leading conductor of a drilling device. The sensor unit of the gyrocompass device moves with the movement of the moving body, and takes the same direction and posture as the moving body. Such a structure is generally called a strap-down method.
[0029]
When the gyrocompass device of this example is used as a strap-down type compass mode, the calculation unit 2 inputs the output signal of the moving body coordinate system from the sensor unit 1, and determines the azimuth and attitude angle of the local coordinate system. Calculate. In the compass mode, the turntable is rotated by ± 180 ° in a sufficiently short time compared to the compass period, so that an azimuth angle and attitude angle from which error components of the gyroscope and the accelerometer are removed can be obtained. Therefore, it is possible to reduce the azimuth error due to the temperature and aging of the sensor. Note that the gyro drift and accelerometer bias obtained from the drift / bias calculator 3 may be used for the calculation of the azimuth angle and the attitude angle.
[0030]
When the gyro compass device of this example is used as a surveying mode in a stationary state, the drift / bias calculation unit 3 calculates the gyro drift and the accelerometer bias, and further calculates the azimuth angle and attitude angle of the moving object. Calculate and output.
[0031]
With reference to FIG. 4, the structure of the calculating part 2 and the operation | movement of the compass mode of a strapdown system are demonstrated. The calculation unit 2 includes a coordinate transformation matrix calculation unit (CTM calculation unit) 201, a local orientation / posture calculation unit 202, a local acceleration calculation unit 203, and a compass / correction calculation unit 204. The CTM calculation unit 201 inputs the angular velocity of the moving body coordinate system output from the X, Y, and Z gyros, and calculates and outputs a coordinate transformation matrix (CTM). As described above, the error of the output of the X and Y gyros is eliminated by the rotation of ± 180 ° of the turntable.
[0032]
The coordinate transformation matrix (CTM) is a 3 × 3 matrix for transforming moving body coordinates into local (local) coordinates. CTM is known and will not be described here. For details, see, for example, Japanese Patent Application No. 5-779 filed on Jan. 6, 1993 by the same applicant as the present application.
[0033]
The local acceleration calculation unit 203 includes the acceleration of the moving body coordinate system output from the X, Y, and Z accelerometers 11A, 12A, and 13A and the coordinate conversion matrix (CTM) output from the coordinate conversion matrix (CTM) calculation unit 201. The rotation angle signal of the turntable output from the direction transmitter 13Y is input to calculate the acceleration of the local coordinate system.
[0034]
The compass correction calculation unit 204 inputs the local coordinate system acceleration output from the local acceleration calculation unit 203 and the rotation angle signal of the turntable output from the azimuth transmitter 13Y, and performs compass control calculation and azimuth correction calculation. Then, a torque signal, which is a control signal, is generated and output to the coordinate transformation matrix (CTM) calculation unit 201.
[0035]
The local azimuth / attitude calculation unit 202 calculates the azimuth angle and posture angle (roll angle and pitch angle) of the local coordinate system from the calculation result output from the coordinate transformation matrix (CTM) calculation unit 201. The azimuth angle and the attitude angle of the local coordinate system calculated in this way are free from errors of the XY gyroscope and the XY accelerometer by the rotation of ± 180 ° of the turntable.
[0036]
The survey mode operation will be described with reference to FIGS. Consider a point P at latitude λ in the northern hemisphere of the earth as shown in FIG. Let the center of the earth be O and the point where the meridian passing through point P intersects the equator plane is P_OAnd the rotation axis of the earth is OP_NAnd Latitude λ of point P is ∠POP_OIt is. A horizontal plane H at the point P is a tangential plane with respect to the earth surface.
[0037]
Earth rotation angular velocity vector Ω_EIs the rotation axis OP as shown_NFacing the direction. Earth rotation angular velocity vector Ω_EIs the horizontal component HER (Horizontal Earth Rate) in the direction of true north (arrow N) on the horizontal plane H, that is, Ω_Ecos λ and vertical component (Vertical Earth Rate), that is, Ω_EIt can be decomposed into sin λ.
[0038]
As shown in FIG. 6, it is assumed that a gyrocompass device, that is, a moving body is arranged on a horizontal plane H at a point P. The orientation of the moving body is aligned with the x-axis as described above. Let the azimuth angle NPx of the moving body be Φ. PX input axis of X gyro PX_GS, PY the input axis of the Y gyro_GS, The input axis of the Z gyro is PZ_GSAnd
[0039]
A rotation angle of the input axis of the X gyro with respect to the azimuth Px of the moving body is φ. It is assumed that the rotation angle of the turntable is equal to the rotation angle φ of the input axis of the X gyro. X gyro input axis azimuth ∠ NPX_GSIs Φ + φ. Y gyro input axis azimuth angle NPY_GSIs Φ + φ + 90 °.
[0040]
X gyro is the Earth's rotation angular velocity vector Ω_EInput axis PX_GSDirectional component is detected, Y gyro is the earth rotation angular velocity vector Ω_EInput axis PY_GSThe direction gyro is detected and the Z gyro_EInput axis PZ_GSThe direction component is detected. Therefore, the output ω of the X, Y, Z gyro_X, Ω_Y, Ω_zIs expressed as follows.
[0041]
[Expression 1]
ω_X = Ω_E cos λ cos (Φ + φ) + U_X
ω_Y =−Ω_E cos λ sin (Φ + φ) + U_Y
ω_Z = -Ω_E sin λ + U_Z
[0042]
Where Ω_EIs the rotational angular velocity of the earth, and λ is the latitude. Φ is the orientation of the moving body, that is, the rotation angle with respect to the meridian of the x axis, φ is the rotation angle of the X gyro with respect to the orientation of the moving body, U_X, U_Y, U_ZIs the gyro drift respectively. Z gyro output ω_zThe negative sign is attached because the Z gyro is mounted so that the direction of the input axis is in the negative direction of the z axis. In this example, the rotational angular velocity around the y axis and the rotational angular velocity around the x axis are zero, that is, dθ / dt = 0 and dσ / dt = 0.
[0043]
The above example is a gyrocompass device, that is, a case where the moving body is arranged on the horizontal plane H, but consider a case where the moving body is inclined. The input axis PX of the moving body is X gyro_GSConsider a case where the rotation is biased around the rotation angle σ.
[0044]
This will be described with reference to FIG. FIG. 7 shows the input axis PX of the X gyro_GSAnd Y gyro input axis PY_GSThe surface formed by is shown. X, Y, Z gyro output ω_X, Ω_Y, Ω_ZIs expressed as follows.
[0045]
[Expression 2]
ω_X = Ω_E cos λ cos (Φ + φ) + U_X
ω_Y = -Ω_E sin λ sinσ−Ω_E cos λ sin (Φ + φ) cosσ + mg sinσ + qg cosσ + U_Y
ω_Z = -Ω_E sin λ cosσ−Ω_E cos λ sin (Φ + φ) sinσ-mg cosσ + qg sinσ + U_Z
[0046]
Where σ is the input axis PX of the moving body with respect to the horizontal plane H_GSThe tilt angle around. The tilt angle σ is detected by a Y accelerometer. mg is a mass unbalance caused by deviation of the center of gravity of the gyro rotor, and qg is a crosstalk amount caused by a change in the input angular velocity of the counterpart shaft. These are TDG specific errors. X, Y, Z gyro output ω_X, Ω_Y, Ω_ZIn order to obtain the azimuth angle Φ of the moving body, the gyro drift U_X, U_Y, U_ZIt is necessary to ask. The gyro drift U_X, U_Y, U_ZA method for obtaining the value will be described.
[0047]
The rotating table is stopped by rotating at a certain rotation angle Δφ = 2π / n (for example, every 60 ° with n = 6), and the output signals ω of the three gyros are stopped._X, Ω_Y, Ω_ZAnd the output signal σ of the Y accelerometer. N sets of measured values ω by rotating the turntable once_Xi, Ω_Yi, Ω_Zi, Σ_i(I = 1 to n) shall be obtained. Of these measured values, attention is paid to data whose rotation angles φ differ from each other by 180 °. For example, the output signal of the X, Y, Z gyro for the rotation angle φ is ω_X1, Ω_Y1, Ω_Z1The output signal of the X, Y, Z gyro for the rotation angle φ + π is ω_X2, Ω_Y2, Ω_Z2These are expressed as follows.
[0048]
[Equation 3]
ω_X1= Ω_Ecos λ cos (Φ + φ) + U_X
ω_X2= Ω_Ecos λ cos (Φ + φ + π) + U_X
[0049]
ω_Y1= -Ω_E sin λ sinσ₁ −Ω_E cos λ sin (Φ + φ) cosσ₁+ Mg sinσ₁ + Qg cosσ₁ + U_Y
ω_Y2= -Ω_E sin λ sinσ₂ −Ω_E cos λ sin (Φ + φ + π) cosσ₂+ Mg sinσ₂ + Qg cosσ₂ + U_Y
[0050]
ω_Z1= -Ω_Esin λ cosσ₁−Ω_Ecos λ sin (Φ + φ) sinσ₁
−mg cosσ₁+ Qg sinσ₁+ U_Z
ω_Z2= -Ω_Esin λ cosσ₂−Ω_Ecos λ sin (Φ + φ) sinσ₂
−mg cosσ₂+ Qg sinσ₂+ U_Z
[0051]
Where σ₁, Σ₂Are the inclination angles around the input axis of the X gyro of the movable body or the base 10 with respect to the horizontal plane H when the rotation angles of the turntable are φ and φ + π, respectively. These two inclination angles σ₁, Σ₂There is the following geometric relationship between them.
[0052]
[Expression 4]
σ₁= −σ₂
[0053]
Substituting this into the equation (3) for transformation yields the following relationship.
[0054]
[Equation 5]
ω_X1= Ω_Ecos λ cos (Φ + φ) + U_X
ω_X2= -Ω_Ecos λ cos (Φ + φ) + U_X
[0055]
ω_Y1= -Ω_E sin λ sinσ₁ −Ω_E cos λ sin (Φ + φ) cos σ₁+ Mg sinσ₁ + Qg cosσ₁ + U_Y
ω_Y2= Ω_E sin λ sinσ₁ +Ω_E cos λ sin (Φ + φ) cos σ₁−mg sinσ₁ + Qg cosσ₁ + U_Y
[0056]
ω_Z1= -Ω_Esin λ cosσ₁−Ω_Ecos λ sin (Φ + φ) sin σ₁
−mg cosσ₁+ Qg sinσ₁+ U_Z
ω_Z2= -Ω_Esin λ cosσ₁+ Ω_Ecos λ sin (Φ + φ) sin σ₁
−mg cosσ₁-Qg sinσ₁+ U_Z
[0057]
From these six equations, six unknowns U_X, U_Y, U_Z, Mg, qg, and Φ can be obtained. First, the following relational expression is obtained from these expressions.
[0058]
[Formula 6]
ω_X1+ Ω_X2= 2U_X
ω_X1−ω_X2= 2Ω_E cos λ cos (Φ + φ)
ω_Y1+ Ω_Y2= 2U_Y + 2qg cosσ₁
ω_Y1−ω_Y2= 2Ω_E [-Sin λ sinσ₁ −cos λ sin (Φ + φ) cos σ₁ ] + 2mg sinσ₁
ω_Z1+ Ω_Z2= -2Ω_E sin λ cosσ₁ -2mg cosσ₁ + 2U_Z
ω_Z1−ω_Z2= -2Ω_E cos λ sin (Φ + φ) sin σ₁ + 2qg sinσ₁ + 2U_Z
[0059]
Next, from these six equations, six unknowns U_X, U_Y, U_Z, Mg, qg, and Φ can be obtained.
[0060]
[Expression 7]
U_X= (Ω_X1+ Ω_X2) / 2
U_Y= (Ω_Y1+ Ω_Y2) / 2-qg cosσ₁
U_Z= (Ω_Z1+ Ω_Z2) / 2 + Ω_Esin λ cosσ₁+ Mg cosσ₁
Φ = cos^-1[(1 / 2Ω_E) (Ω_X1−ω_X2)] / (Cosλ)] -φ
qg = [(ω_Y1+ Ω_Y2) / 2-U_Y] / Cos σ₁
mg = (Ω_E/ Sin σ₁) [-Sin λ sinσ₁+ Cos λ sin (Φ + φ) cos σ₁]-(Ω_Y1−ω_Y2) / 2sin σ₁
[0061]
The azimuth angle Φ of the moving object is the output ω of the X gyro_XIt was calculated | required from (2nd Formula of Formula 6). If the inclination of the input axis of the X gyro is zero as in this example, that is sufficient. However, if the slope of the input axis of the X gyro is not zero, the output ω of the Y gyro_YIt is calculated from (the fourth equation of the equation 6).
[0062]
[Equation 8]
Φ = sin^-1[− [{(Ω_Y1−ω_Y2) -2mg sinσ₁ } / 2Ω_E + Sin
λsinσ ₁ ]/ Cos λ cosσ₁ ] -Φ
[0063]
Here, for simplification, if the mass unbalance mg and the crosstalk amount qg are ignored as known, the following relationship is obtained.
[0064]
[Equation 9]
U_X = (Ω_X1+ Ω_X2) / 2
U_Y = (Ω_Y1+ Ω_Y2) / 2
U_Z = (Ω_Z1+ Ω_Z2) / 2 + Ω_E sin λ cosσ₁
Φ = sin^-1[−{(1 / 2Ω_E ) (Ω_Y1−ω_Y2) + Sin λ sinσ₁ } / (Cosλcosσ₁)]-Φ
[0065]
Next, a method of detecting the bias Δσ included in the output signal σ of the Y accelerometer and detecting the inclination angle σ around the true x axis will be described. Similarly, if the turntable is rotated every fixed rotation angle Δφ = 2π / n (for example, every 60 ° with n = 6), the rotation table stops and the output signal σ of the Y accelerometer is stopped._MMeasure. N sets of measured values σ by rotating the turntable once_Mi(I = 1 to n) shall be obtained. Of these measured values, attention is paid to data whose rotation angles φ differ from each other by 180 °. For example, the output signal of the Y accelerometer for the rotation angle φ is σ_M1The output signal of the Y accelerometer when the rotation angle is φ + π is σ_M2Then, it is expressed as follows.
[0066]
[Expression 10]
σ_M1= Σ₁+ Δσ
σ_M2= Σ₂+ Δσ
[0067]
Where σ₁, Σ₂Is the tilt angle around the x-axis of the turntable 10 when the rotation angle is φ and φ + π when the bias Δσ is zero, as described above. Tilt angle σ around these two x-axes₁, Σ₂There is a relation of the formula 4 in between. Therefore, the following relationship is obtained from the equation (9).
[0068]
## EQU11 ##
σ_M1−σ_M2= Σ₁−σ₂= 2σ₁
σ_M1+ Σ_M2= Σ₁+ Σ₂+ 2Δσ = 2Δσ
[0069]
Therefore, when the rotation angle of the turntable is φ, the inclination angle σ around the true x-axis₁And the bias Δσ of the Y accelerometer is expressed by the following equation.
[0070]
[Expression 12]
σ₁= (Σ_M1−σ_M2) / 2
Δσ = (σ_M1+ Σ_M2) / 2
[0071]
When the rotation angle of the turntable is φ, the tilt angle θ around the true y axis₁And the X accelerometer bias [Delta] [theta] is determined in a similar manner and is given by the same equation as Equation 12, but will not be described in detail here.
[0072]
According to this example, n sets of measured values ω are obtained by rotating the turntable once._Xi, Ω_Yi, Ω_Zi, Σ_i, Θ_i(I = 1 to n) is obtained. Accordingly, there are n / 2 sets of measured values in which the rotation angles φ of the turntables are different from each other by 180 °. n / 2 sets of data Φ, U from n / 2 sets of measured values_X, U_Y, U_Z, Σ₁, Δσ, Δθ are obtained. Therefore, by obtaining these average values or least square approximation values, more accurate Φ, U_X, U_Y, U_Z, Σ₁, Δσ, θ₁, Δθ is obtained.
[0073]
The configuration and operation of the drift / bias calculation unit 3 will be described with reference to FIG. The drift / bias calculation unit 3 includes a rotation control unit 71, a sequencer unit 72, a data measurement storage unit 73, an azimuth calculation unit 74, and a calculation unit 75.
[0074]
In the rotation control unit 71, the rotation angle φ of the turntable is set to the set rotation angle φ._SFunctions to be equal to The rotation control unit 71 sets the set rotation angle φ generated by the sequencer unit 72._SIs supplied to the azimuth servo motor 22. The azimuth servo motor 22 operates to rotate the turntable around the rotation axis. The direction transmitter 13Y detects the rotation angle φ of the turntable and outputs it to the rotation control unit 71. The output signal φ of the bearing transmitter 13Y is the set rotation angle φ_SThe data measurement storage unit 73 measures and stores the data of the turntable.
[0075]
The data measurement storage unit 73 outputs the output signal ω of the X, Y, Z gyro._X, Ω_Y, Ω_Z, Set rotation angle φ_S= Φ and the tilt angle θ and σ output from the XY accelerometer (the clockwise direction is set to +) are input. Next, the sequencer unit 72 sets a new set rotation angle φ_S= Φ_S+ Δφ is generated and supplied to the rotation control unit 71. The rotation control unit 71 determines that the output signal φ of the direction transmitter 13Y is a new set rotation angle φ._SThe azimuth servo motor is operated so as to be equal to.
[0076]
Thus, the output signal φ of the direction transmitter 13Y is changed to a new set rotation angle φ._SThe data measurement storage unit 73 measures and stores the gyro data. Accordingly, the data measurement storage unit 73 stores the set rotation angle φ_SStore every data.
[0077]
The data measurement storage unit 73 has a set azimuth angle φ_S= Φ_iEvery data ω_Xi, Ω_Yi, Ω_{Z i}, Σ_i, Θ_i(I = 1 to n) are sequentially stored. A large number of data φ stored in the data measurement storage unit 73_i, Ω_Xi, Ω_Yi, Ω_Zi, Σ_i, Θ_i(I = 1 to n) are sequentially supplied to the azimuth calculation unit 74 and the calculation unit 75. The arithmetic unit 75 can calculate the gyro drift U by the formulas (7) to (12)._X, U_Y, U_ZThe accelerometer biases Δσ and Δθ and the attitude angles σ and θ are calculated, and the azimuth calculating unit 74 calculates the azimuth Φ of the turntable.
[0078]
With reference to FIGS. 1 and 2 again, a second example of the present invention will be described. The above-described example is a strap-down type gyrocompass device, but the example described below is a semi-strapdown-type gyrocompass device.
[0079]
Roll shafts 53 are attached to both ends of the base 10. This roll shaft 53 is rotatably mounted on a disc 52 of the casing. A contactless DST (direct servo torquer) may be used to rotate the base 10 around the roll axis 53. A rotary transformer may be used for supplying power to the sensor mounted on the turntable and transmitting / receiving signals. Further, the gyrocompass device is provided with a mechanism for controlling the base 10 around the roll shaft 53, whereby the base 10 is always held at a predetermined roll position (horizontal position). Accordingly, the sensor unit of the gyrocompass device moves with the movement of the moving body while being held at a predetermined roll position, and assumes the same posture as the moving body. This is referred to herein as a semi-strap down method.
[0080]
In the semi-strap down method, the base and the gyrocompass device are connected to the X-gyro input axis PX._GSAlways around a predetermined rotational position. Therefore, in the above discussion, the rotation angle σ = 0 may be set.
[0081]
Although examples of the present invention have been described above, it will be understood by those skilled in the art that the present invention can be modified in various ways within the scope of the invention described in the claims.
[0082]
【The invention's effect】
According to the present invention, there is an advantage that it is possible to provide a gyrocompass device that is small in size and has a high accuracy of a small diameter and is inexpensive for measuring the position of an object in the ground or underwater.
[0083]
According to the present invention, there is an advantage that the position of a relatively small diameter pipe such as a sewer pipe can be measured accurately and without digging up the ground.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a main part of a gyrocompass device according to the present invention.
FIG. 2 is a diagram showing an example of a main part of another example of the gyrocompass device of the present invention.
FIG. 3 is a diagram showing an example of the overall configuration of a gyrocompass device according to the present invention.
FIG. 4 is a diagram illustrating a configuration example of a calculation unit of the gyrocompass device of the present invention.
FIG. 5 is an explanatory diagram for explaining a rotation angular velocity vector of the earth.
FIG. 6 is an explanatory diagram for explaining a component of an earth rotation angular velocity vector detected by an XYZ gyro;
FIG. 7 is an explanatory diagram for explaining the components of the rotation angular velocity vector of the earth detected by the XYZ gyro when the gyro compass device is tilted.
FIG. 8 is a diagram illustrating a configuration example of a drift / bias calculation unit of the gyrocompass device of the present invention;
FIG. 9 is an explanatory diagram for explaining an example of a conventional excavator;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Base, 11A, 12A, 13A ... Accelerometer, 11G, 12G, 13G ... Gyro, 13Y ... Direction transmitter, 20 ... Turntable, 50 ... Casing, 51・ ・ ・ Cylindrical part, 52 ・ ・ ・ Disc part, 53 ・ ・ ・ Roll shaft, 201 ・ ・ ・ Excavation blade, 202 ・ ・ ・ Tip conduit, 203 ・ ・ ・ Guide member, 210A, 210B, 210C, 210D, 210E ... Hume pipe, 220 ... Main push pipe, 205 ... Supply pipe, 206 ... Discharge pipe, 207 ... Pump

Claims (5)

A cylindrical casing having a central axis, a base disposed in the casing, a sensor unit mounted on the base and including an XYZ gyro, an XYZ accelerometer, and a direction transmitter; An arithmetic unit that converts the output signal into a signal on the Earth's surface coordinate system, and a drift bias calculation that calculates the base orientation, gyro drift, and acceleration bias from the signal output from the sensor unit in the survey mode. And the base includes a plurality of turntables arranged along the central axis and a driving device for synchronously rotating the plurality of turntables. A gyrocompass device, wherein the gyrocompass device is mounted on the turntable so that an input axis or a measurement axis is aligned with the central axis. 2. The gyro compass apparatus according to claim 1, wherein the XYZ gyro is composed of a TDG (tuned dry gyro). The computing unit computes the acceleration of the earth surface coordinate system using the coordinate transformation matrix computing unit for computing a coordinate transformation matrix for transforming the coordinate system provided on the base to the earth surface coordinate system and the coordinate transformation matrix. 2. The gyrocompass device according to claim 1, further comprising a local acceleration calculation unit and a local azimuth / posture calculation unit that calculates the azimuth and posture of the earth surface coordinate system. The drift / bias calculation unit includes a rotation control unit that controls the rotation of the turntable, a data measurement storage unit that stores outputs of the XYZ gyro and the XYZ accelerometer using the azimuth angle of the turntable as a parameter, and the data measurement storage A calculation unit that calculates drift and bias of the output of the XYZ gyro and XYZ accelerometer from an output from the unit, and an azimuth calculation unit that calculates the azimuth of the base, and the above at a plurality of rotation angles of the turntable 2. The gyro compass device according to claim 1, wherein the gyro compass device is configured to detect a bias and a drift of the sensor unit from an output of the sensor unit. The gyrocompass device according to claim 1, wherein an outer diameter of the cylindrical casing is 80 mm or less.

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