JP3055642B2 - Absolute azimuth measuring device for slow moving objects - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield tunnel excavator, a propulsion method excavator mainly used in the civil engineering and construction fields,
20cm / mi for semi-shield excavator, tunnel boring machine, drill jumbo or underground wall excavator
The present invention relates to an absolute azimuth measuring device for a moving object that moves at a low speed of n or less. In particular, the absolute azimuth can be measured in real time, the sensor portion is small and energy saving, and the absolute speed of an object moving at a low speed that is easy to maintain and handle The present invention relates to an azimuth measuring device.

[0002]

2. Description of the Related Art Excavators that excavate underground are widely used in the field of civil engineering and construction. As shown in FIG. 4, for example, a shield machine 41 having a medium diameter has a diameter of 2000 mm.
The rotary drilling blade 4 is mounted on the head of the above-mentioned substantially cylindrical main body 42.
3 is provided. The digging blade 43 is installed in the direction in which the digging should proceed, and the body 42 is advanced while rotating the digging blade 43 to operate. The excavated earth and sand is discharged, and the tunnel 4
4 are formed. At this time, it is necessary to monitor the traveling direction of the shield machine 41 so as not to deviate from the planned tunnel. Since the shield machine 41 is driven underground,
There is nothing to confirm the direction. Therefore, in order to confirm the traveling direction, it is necessary to measure the direction in which the shield machine 41 is heading. The moving speed of the shield machine 41 is 20 cm / min or less (for example, 4.5 cm / mi).
In order to detect the change in the traveling direction because of the low speed of n), a detecting means suitable for such a low moving speed is required.

As a direction sensor mounted on a moving object to detect the direction of the object, a mechanical gyro compass is well known. The mechanical gyro compass utilizes the inertia of a rotating body that is rotated at a high speed, and detects a change in the azimuth of the moving body by a change in the angle of the rotating body. The mechanical gyro compass 45 is mounted on the shield machine 41 shown in FIG. The direction detected here is monitored by a computer (display device) 46 on the ground or in the driver's seat of the shield machine 41.

In recent years, an optical fiber gyro utilizing the property of light propagating in an optical fiber is often used. That is, when the optical fiber is formed into a loop and light having the same properties is propagated in the forward and reverse directions, the rotational angular velocity on the loop surface can be detected from the difference between the returning lights. By integrating the rotational angular velocity, the displacement angle from the original azimuth can be obtained,
If a reference azimuth is given first, the azimuth of the moving object can be detected by accumulating the displacement angles. This sensor is called an optical fiber rotational angular velocity sensor or simply a rotational angular velocity sensor.

Further, since the optical fiber gyro has a very high detection accuracy of the rotational angular velocity, it is possible to detect the rotational angular velocity due to the rotation of the earth if the loop is set up. If the loop is stationary with respect to the earth, the detected rotational angular velocity is a component of the rotational angular velocity of the earth in the loop direction, so that the direction in which the loop faces can be measured based on this. The direction obtained from the rotation of the earth is
Since this is an absolute reference, this is hereinafter referred to as an absolute direction.
This sensor is called an optical fiber gyro direction sensor or simply a direction sensor.

[0006]

By the way, the mechanical gyro compass has the merit that the direction of an object can be detected in real time, but the measurement accuracy is ± 0.
It is about 2 °, which is inferior to the optical fiber gyro. Also,
There are inconveniences in handling, such as the fact that it takes 5 to 6 hours from the start to the start of a normal measurement and that regular maintenance is required. In addition, since it is large in size and requires a cubic space of about 40 cm on a side for mounting, there is a problem with the space when housed in the shield machine.

On the other hand, when an optical fiber gyro is used,
The accommodation space is small, and the driving power supply may be small. Also, since there is no mechanically moving part, no maintenance is required, the startup time is short, and the handling is easy. However, there are drawbacks.

That is, the rotational angular velocity sensor has a higher resolution (measurement accuracy) than a mechanical gyro compass, but cannot detect an absolute azimuth directly from the sensor. Further, even with a high-accuracy rotational angular velocity sensor, a drift of about 0.1 ° / h occurs. Therefore, when the sensor is used continuously for a long time, errors due to this drift (shift of the zero reference point over time) are accumulated and become large. .

On the other hand, the direction sensor can directly detect the absolute direction and has high accuracy. However, it takes about 5 minutes for one measurement, and it is impossible to detect the absolute azimuth in real time. In addition, during measurement, it is necessary to prevent angular velocity components other than the angular velocity of the earth from being superimposed, that is, to maintain a stationary state or a state close thereto.

[0010] For this reason, it has been insufficient to replace the rotational angular velocity sensor alone or the azimuth sensor alone with the mechanical gyro compass.

Therefore, an object of the present invention is to solve the above-mentioned problem by combining a rotational angular velocity sensor and an azimuth sensor, to be able to measure the absolute azimuth in real time, to reduce the size of the sensor portion and to save energy, and to perform maintenance and handling. An object of the present invention is to provide an absolute azimuth measuring device for an object that moves easily at a low speed.

[0012]

To accomplish the above object means to provide a process, the moving object of excavator or the like burrowing underground following a low speed 20 cm / min, an optical fiber sensing loop is erected vertically Time by detecting the rotation of the earth
An optical fiber gyro azimuth sensor for obtaining the absolute azimuth from the rotational angular velocity, and an optical fiber rotational angular velocity sensor for detecting the rotational angular velocity of the object are provided to measure the absolute azimuth of the object and to determine the rotational angular velocity and displacement angle of the object. In the measurement device, when the angular velocity detected by the rotational angular velocity sensor is equal to or less than a predetermined angular velocity Ω, the absolute direction is measured by the direction sensor, and the displacement control of the rotational angular velocity sensor is reset to the measured absolute direction. It is provided with a part.

Further, when the required accuracy required for absolute azimuth measurement is Δθ, and the time required for measurement of the azimuth sensor is T, the reference angular velocity Ω is preferably Ω = Δθ / T.

When the angular velocity detected by the rotational angular velocity sensor is equal to or higher than Ω, the measurement control section obtains a displacement angle from the angular velocity.

When the angular velocity becomes equal to or higher than Ω during the measurement of the absolute azimuth by the azimuth sensor, the measurement controller repeats the measurement.

If the angular velocity detected by the rotational angular velocity sensor is equal to or less than Ω before the measurement of the absolute azimuth by the azimuth sensor, the measurement control section eliminates the offset of the rotational angular velocity sensor. If the detected angular velocity (drift) is equal to or higher than Ω, offset cancellation is performed again.

The azimuth sensor and the rotational angular velocity sensor are separated into a sensor main body and a signal processing circuit, and these sensor main body and the signal processing circuit are arranged separately.

[0018]

With the above arrangement, if the angular velocity detected by the rotational angular velocity sensor is equal to or less than the predetermined angular velocity Ω, it is considered that the change in the azimuth of the moving object is small. Also, the movement of the object is slow. Therefore, the azimuth sensor is almost stationary, and the measurement result is reliable. When the displacement angle of the rotational angular velocity sensor is reset to this measured absolute azimuth,
Thereafter, the displacement angle measured by the rotational angular velocity sensor is not affected by the measurement error up to that time. If this displacement angle is added to the absolute azimuth, the real-time absolute azimuth can be detected.

When the required accuracy required for absolute azimuth measurement is high (.DELTA..theta. Is small), it is only necessary that the azimuth sensor is in a state of being close to stationary, so that the reference angular velocity .OMEGA. Further, even when the measurement time of the azimuth sensor is long (T is large), the azimuth change within that time may be small, so that the reference angular velocity Ω may be reduced. Therefore, if Ω = Δθ / T, the absolute azimuth can be measured with sufficient accuracy.

When the angular velocity detected by the rotational angular velocity sensor is equal to or higher than Ω, the direction sensor is not used because it is not accurate. Instead, the real-time absolute azimuth can be obtained by calculating the displacement angle from the angular velocity.

If the angular velocity becomes Ω or more during the measurement of the absolute azimuth by the azimuth sensor, the measurement is interrupted because the azimuth sensor at this time is not accurate. By re-measuring,
Only the measurement result of the absolute azimuth when the angular velocity does not exceed Ω during the measurement can be obtained.

If the angular velocity detected by the rotational angular velocity sensor is equal to or less than Ω, this can be regarded as noise (referred to as offset) inherent to the rotational angular velocity sensor. Therefore, the offset of the rotational angular velocity sensor is eliminated so that the detected angular velocity becomes zero. After the offset is eliminated, the angular velocity detected again corresponds to the drift. If this drift is Ω or more, it is considered that offset cancellation failed. Therefore, offset cancellation is performed again. If the drift is Ω or less, it is considered that the offset cancellation was successful.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an example in which the present invention is applied to a medium-diameter shield machine having a diameter of 2000 mm or more. A rotary drilling blade 4 is mounted on the head of the substantially cylindrical main body 42.
3 and the shield machine 41 that digs underground
The object 1 moves at a low speed of not more than cm / min. In the object 1, a sensor main body 4 including an optical fiber gyro azimuth sensor 2 and an optical fiber rotational angular velocity sensor 3 is provided at the head of the shield machine 41. The azimuth sensor 2 is an upright optical fiber sensing loop in which an optical fiber is formed in a loop shape such that the loop surface is substantially perpendicular to the earth, and can measure an absolute azimuth. The rotation angular velocity sensor 3 has an optical fiber sensing loop disposed so that its loop surface matches the rotation direction of the object 1 to be detected. For example, if the loop surface is horizontal, the rotation angular velocity in the horizontal direction is well detected. can do.

The sensor body 4 incorporates optical components such as an optical fiber sensing loop and a signal amplifier such as a preamplifier as the rotational angular velocity sensor 3. The sensor body 4 has the configuration shown in FIG. That is, the optical components 21 such as the sensing loop
And a turntable 22 on which the optical component 21 is mounted so as to be rotatable, and a leveling mechanism 23 for supporting the turntable 22 and adjusting the inclination of the turntable 22 in two horizontal directions. The leveling mechanism 23 includes a leveling table 24 that supports the turntable 22 and four levels of the leveling table 24.
Four leveling rods 25 that can be raised and lowered independently while supporting the corners, two inclinometers 26 that are mounted on a leveling table 24 and detect tilts in two horizontal directions perpendicular to each other, and a leveling mechanism for these 23
And a leveling mechanism main body 27 that adjusts the inclination of the leveling table 24. The azimuth sensor 2 can maintain the optical component 21 such as the sensing loop perpendicular to the earth by the leveling mechanism 23. Further, by rotating the turntable 22, the optical component 21 can be directed to an arbitrary direction.

FIG. 1 shows a signal processing circuit 5. The signal processing circuit 5 is a circuit that processes each detection signal from the sensor main body 4, and is disposed behind the shield machine 41 in the present embodiment. The signal processing circuit 5 includes the RS4
22, is connected to a computer (display device) 46 on the ground via a communication line 7 conforming to a standard such as a current loop. The computer (display device) 46 may be installed in the driver's seat of the shield machine 41.

The measurement of the absolute direction of the object 1 by the direction sensor 2 and the measurement of the rotational angular velocity and the displacement angle of the object 1 by the rotational angular velocity sensor 3 are controlled by a signal processing circuit 5.
That is, the signal processing circuit 5 is the measurement control unit 6, and the outline of the control procedure is shown in FIG. In FIG.
GC is the azimuth sensor 2, OFG is the rotational angular velocity sensor 3, and Ω (° / sec) is a reference value when executing this control procedure, and represents the required accuracy required for absolute azimuth measurement. [Delta] [theta] ([deg.]), And when the time required for measurement by the absolute direction sensor is T (sec), there is a relationship of Ω = [Delta] [theta] / T.

Next, the operation of the embodiment will be described.

In FIG. 3, first, in step S1, the angular velocity detected by the rotational angular velocity sensor 3 (hereinafter, OFG) is compared with a reference value Ω. If the angular velocity ≦ Ω, the change in the azimuth of the object 1 is considered to be very small, and the movement of the object 1 is slow. Therefore, the azimuth sensor 2 (GC) is almost stationary, and the measurement result at that time is reliable. Therefore, the absolute direction is measured by GC, but before that, O
Adjust the offset and drift of the FG.

Here, the offset is noise inherent in the optical fiber gyro, and is detected as an angular velocity even when the optical fiber gyro is stationary. The offset is caused by the fluctuation of the light source, the reflection in the optical fiber, the electromagnetic wave received by the circuit, the fluctuation of the temperature of the circuit, and the like, and the sensor output is not zero even though the actual angular velocity is zero. It is necessary to eliminate this offset for correct angular velocity detection. Specifically, an average value of the output over a certain period of time is obtained, and this average value is subtracted from the output. This processing is called offset cancellation, and is performed by the signal processing circuit 5.

The drift is a deviation of the zero reference point with the passage of time. If the time elapses when the optical fiber gyro is stationary, the angular velocity detected even after the offset cancellation is performed. Is not 0. This drift accumulates over time and increases. Drift is eliminated by repeating offset cancellation.

In order to adjust the offset and the drift,
In step S2, the angular velocity of the OFG is regarded as noise, and the offset of the OFG is eliminated so that this angular velocity becomes zero (indicated by "oc" in the figure). After the offset is eliminated (S3), if the angular velocity (drift) detected again is equal to or more than Ω, it is considered that the offset has failed, and the offset is eliminated again. If the drift is equal to or less than Ω, it is considered that the offset cancellation has been successful, and the process proceeds to step S4.

At S4, the measurement of the absolute azimuth by GC is started. Since this measurement requires time T, the OFG measurement is repeated until the measurement result is obtained (S6) (S6).
5). If the angular velocity becomes Ω or more in S5, the GC at this time
Is not accurate, the measurement is repeated (S7). Thus, only the measurement result of the absolute azimuth when the angular velocity does not exceed Ω during the measurement is obtained.

In step S8, the measured GC data is used as initial data of the OFG displacement angle measurement. The displacement angle measured by the OFG in S9 is not affected by the measurement error up to that time. Since this displacement angle is initialized by the GC data, it represents a real-time absolute azimuth.

Returning to S1, when angular velocity> Ω,
Since GC is not accurate, it is not used to initialize OFG. Instead, if the angular velocity is greater than Ω, it is considered to be a significant angular velocity in terms of measurement accuracy. That is, a real-time absolute azimuth can be obtained even when the angular velocity is large.

Thus, even when the shield machine 41 is moving, the rotational angular velocity sensor 3 can obtain a real-time absolute azimuth. When the movement is small (including when the shield machine 41 is stopped), the azimuth sensor 2 obtains the absolute azimuth and the rotation angular velocity sensor 3 is initialized. By this initialization, the real-time absolute azimuth measurement during the movement is accurate without measurement errors being accumulated.

FIG. 5 is a graph showing the results of an experiment in which the tracking accuracy of the direction sensor 2 was obtained. When the azimuth sensor 2 is rotated by an input angle on the turntable 22, the displacement of the output angle detected by the azimuth sensor 2 is shown by a solid line. The amount of error between the input angle and the output angle is indicated by a dotted line. According to FIG. 5, the error amount of the output angle is within the range of 0.05 ° or less. The direction sensor 2 has a tracking accuracy of 0.05
° is achieved.

FIG. 6 shows an experimental result of absolute azimuth measurement by the absolute azimuth measuring device of the present invention. The absolute azimuth measuring device was actually mounted on the shield machine 41 and excavated.
Experiments with a conventional mechanical gyro were also performed. FIG.
In the graph of FIG. 5, when the measured value of the conventional mechanical gyro (mechanical gyro) is compared with the absolute azimuth measuring device of the present invention, the results are almost the same. You can see that they are following well. Here, the resolution of the direction sensor 2 is 0.2 ° / h, and the integration time is 5 seconds. The azimuth sensor 2 measures the rotation angle of the earth at 36 ° intervals, and the pointing accuracy is 0.05 °. The resolution of the rotational angular velocity sensor 3 is 0.2 ° / h, and the integration time is 1 second. While the shield machine 41 is stopped, the azimuth sensor 2 outputs true north at intervals of 5 minutes.
The azimuth displacement is output every second.

[0039]

According to the present invention, the absolute azimuth of an object moving at a low speed such as an excavator digging at a low speed of 20 cm / min or less in the ground is obtained by combining an optical fiber rotational angular velocity sensor and an optical fiber gyro azimuth sensor. Since the detection is performed in real time and a mechanical gyrocompass is not used, the following effects are exhibited.

(1) Periodic maintenance is not required.

(2) Since the time required for activation is short, measurement can be performed at any time without continuous operation of the sensor. Therefore, there is no waste of battery power due to continuous operation of the sensor.

(3) The size of the sensor can be reduced and the space for storing the sensor can be small.

(4) Since the handling is easy, the reliability work efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a shield machine showing one embodiment of the present invention.

FIG. 2 is a perspective view of an absolute direction sensor.

FIG. 3 is a flowchart illustrating a control procedure of a measurement control unit.

FIG. 4 is a sectional view of a shield machine showing a conventional example.

FIG. 5 is a graph showing the tracking accuracy of the direction sensor.

FIG. 6 is a graph showing a comparison test result of the absolute azimuth measuring device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Object 2 Orientation sensor 3 Rotational angular velocity sensor 4 Sensor main part 6 Measurement control part

Claims (6)

(57) [Claims] 1. An optical fiber sensing loop, which is vertically erected on a moving object such as an excavator digging at a low speed of 20 cm / min or less underground, detects the rotation of the earth.
An optical fiber gyro azimuth sensor for determining the absolute azimuth from the rotational angular velocity, and an optical fiber rotational angular velocity sensor for detecting the rotational angular velocity of the object are provided to measure the absolute azimuth of the object and determine the rotational angular velocity and displacement angle of the object. In the measurement device, when the angular velocity detected by the rotational angular velocity sensor is equal to or less than a predetermined angular velocity Ω, the absolute direction is measured by the direction sensor, and the displacement control of the rotational angular velocity sensor is reset to the measured absolute direction. An absolute azimuth measuring device for an object moving at a low speed, comprising a unit. 2. When the reference angular velocity Ω is Δθ, the required accuracy required for absolute azimuth measurement is T, and the time required for measurement of the azimuth sensor is T, Ω = Δθ / T. The absolute azimuth measuring device for an object moving at a low speed according to claim 1. 3. The absolute azimuth of an object moving at a low speed according to claim 1, wherein when the angular velocity detected by the rotational angular velocity sensor is equal to or higher than Ω, the measurement control unit calculates the displacement angle based on the angular velocity. Measuring device. 4. The absolute azimuth measurement of an object moving at a low speed according to claim 1, wherein the measurement controller restarts the measurement if the angular velocity becomes Ω or more during the measurement of the absolute azimuth by the azimuth sensor. apparatus. 5. The measurement control section, if the angular velocity detected by the rotational angular velocity sensor is Ω or less before the absolute azimuth measurement by the azimuth sensor, eliminates the offset of the rotational angular velocity sensor. 2. The absolute azimuth measuring apparatus for a low-speed moving object according to claim 1, wherein if the angular velocity (drift) detected again is equal to or more than Ω, the offset is eliminated again. 6. The sensor according to claim 1, wherein the azimuth sensor and the rotational angular velocity sensor are separated into a sensor main body and a signal processing circuit, and the sensor main body and the signal processing circuit are arranged separately. Absolute azimuth measurement device for objects moving at low speed.