JP2006162358A - Apparatus for measuring tip position of horizontal direction excavation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a horizontal excavation tip position measuring apparatus capable of accurately measuring the position of the tip of underground horizontal excavation, in excavation of a horizontal system having a relatively small diameter. <P>SOLUTION: The horizontal excavation tip position measuring apparatus is provided with a target unit 3; a link 4 supported at the target unit 3 via a link support mechanism and having a prescribed link length; a measuring device comprising a measuring unit 5, supported at the rear end of the link 4 via the link support mechanism; and an elastically deformable sleeve pipe in which the target unit 3, the link 4, and the measuring unit 5 are built and which is to be mounted on the rear end of the excavator 1. Every time the amount of excavation by the excavator 1 reaches the link length, the measuring unit 5 converts the angle of the link 3, extending between two points at the center of the sleeve pipe 2, into coordinates with the bearing angles as the reference and the direction of the gravitational acceleration and determines the position of each point of the sleeve pipe. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a horizontal excavation tip position measurement system for accurately grasping the excavation tip position in horizontal excavation such as pipe propulsion work.

  Conventional position measurement methods in horizontal excavation include a method using electromagnetic waves emitted from a target and a method of calculating a position by measuring a relative angle with a target using optical means such as laser light (the following patent document) 1, 2).

Also, the horizontal position of the device using the angle data obtained from the gyro mounted in the propulsion device, the angle data from the inclinometer that detects the inclination of the propulsion device, and the distance data from the distance meter that measures the propulsion distance of the propulsion device When calculating the horizontal displacement of the device being propelled using the position measurement target plate installed in the device, the propulsion of the propulsion device is measured using the survey data and the gyro rotation angle data obtained at the same time. An initial angle detection method and a continuous position detection method for an underground propulsion apparatus that calculate an initial angle with respect to a base line have been proposed (Patent Document 3 below).
Japanese Patent Laid-Open No. 11-023271 JP 2002-48543 A JP-A-11-107679

  However, the above-described method using electromagnetic waves has a problem that the applicable depth is limited, and the use is limited when there is a building on the ground or in soil containing a large amount of metal components such as iron. Further, the method using the optical means described above is easily affected by the working environment, and the operation procedure is complicated. In addition, since humans adjust the optical axis, they cannot be applied unless the tube has a large diameter.

  Further, the position measurement in the conventional horizontal excavation has been difficult to apply in the horizontal excavation such as a pipe having a relatively small diameter.

  In view of the above situation, the present invention accurately measures the position of the underground horizontal excavation tip without being affected by the external environment and the working environment in excavation of a horizontal system such as a pipe having a relatively small diameter. It is an object of the present invention to provide a measurement system for a horizontal excavation tip position.

In order to achieve the above object, the present invention provides
[1] In a horizontal excavation tip position measurement system, a target unit, a link supported by the target unit via a link support mechanism, a link having a predetermined link length, and a link support mechanism at the rear end of the link A measuring device comprising a supported measuring unit, an elastically deformable sleeve tube that incorporates the target unit, the link, and the measuring unit and is attached to the rear end of the excavator, and the amount of excavation by the excavator Each time becomes the link length, the angle of the link passed to the two points at the center of the sleeve tube is converted by the measurement unit into coordinates based on the azimuth angle and the direction of gravitational acceleration, and the position of the target unit is obtained. It is characterized by that.

  [2] The horizontal excavation tip position measurement system according to [1], wherein the sleeve tube is elastically deformed along with a change of a course of the excavator during excavation, and the relative angle between the position of the measurement unit and the link And measuring the position of the target unit.

  [3] In the horizontal excavation tip position measurement system according to [1], the measurement unit includes an inclination sensor and a gyrocompass disposed on a horizontal holding table, and the angle of the link is determined by gravity acceleration and the earth rotation axis. It calculates | requires as a reference | standard and measures the position of the said target unit.

  [4] The horizontal excavation tip position measuring system according to [3], wherein the azimuth angle is measured using the gyrocompass.

  [5] In the horizontal direction excavation tip position measurement system according to [3] above, the measurement unit includes a link support mechanism so that the link can rotate about the Z and Y axes with respect to the horizontal holding table, The link support mechanism is provided with a high-resolution rotary encoder, and the link rotation angle about each Z and Y axis is measured.

  [6] In the horizontal excavation tip position measurement system according to [3], the measurement unit sets two tilt sensors with the sensitivity axes in the X and Y axis directions, and the horizontal holding table It is characterized by automatically keeping the level.

  [7] In the measurement system for the horizontal excavation tip position according to [1], the target unit connects a link and holds a link support point at the center of the sleeve tube at a predetermined distance from the measurement unit. Features.

  [8] In the horizontal excavation tip position measuring system according to [1], the target unit includes a link support mechanism so as to allow rotation about the Z and Y axes, and a high-resolution rotary around each axis. An encoder is provided to measure the inclination angle of the link.

  [9] In the horizontal excavation tip position measurement system according to [1] above, the position and direction of the measurement unit are the same as the position and direction of the target unit before the measurement device moves the same distance as the length of the link. It is possible to reduce the number of times of azimuth measurement by assuming that they match.

  [10] In the horizontal excavation tip position measurement system according to [1], the measurement unit includes an inclination sensor and a gyrocompass on a base, and the target is obtained by a correction method that refers to the latitude of the measurement point. It is characterized by measuring the position of the unit.

  [11] In the horizontal excavation tip position measurement system according to [10] above, the measurement unit includes a link support mechanism so that the link can rotate about the Z and Y axes with respect to the base. The link support mechanism is provided with a high-resolution rotary encoder, and the link rotation angle around each Z and Y axis is measured.

  [12] In the horizontal excavation tip position measurement system according to [10] above, the target unit connects a link and holds a link support point at the center of the sleeve tube at a predetermined distance from the measurement unit. Features.

  [13] In the horizontal excavation tip position measurement system according to [10] above, the target unit includes a link support mechanism so as to allow rotation about the Z and Y axes, and a high-resolution rotary around each axis. An encoder is provided to measure the inclination angle of the link.

  [14] In the measurement system of the horizontal excavation tip position according to [10] above, by assuming that the position of the measurement unit coincides with the position of the target unit before the measurement apparatus moves the same distance as the length of the link It is possible to reduce the number of azimuth measurement times.

  According to the present invention, the horizontal excavation tip position in the ground can be accurately measured in excavation of a horizontal system such as a pipe having a relatively small diameter.

  In addition, since the present invention uses the acceleration of gravity and the axis of rotation of the earth, highly accurate measurement can be performed without being affected by the external environment and the working environment.

  In a horizontal excavation tip position measurement system, a target unit, a link supported by the target unit via a link support mechanism, and a link having a predetermined link length and supported by a rear end of the link via a link support mechanism A measuring device comprising a measuring unit; and an elastically deformable sleeve tube that includes the target unit, the link, and the measuring unit, and is attached to a rear end of the excavator. Each time, the angle of the link delivered to the two points at the center of the sleeve tube is converted into coordinates based on the azimuth angle and the gravitational acceleration direction by the measurement unit, and the position of each point of the sleeve tube is obtained. Therefore, in the horizontal excavation such as a pipe having a relatively small diameter, the horizontal excavation tip position in the ground can be accurately measured.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is an overall configuration diagram of an underground horizontal excavation tip position measuring system showing an embodiment of the present invention.

In this figure, 1 is excavator, 2 _{1, 2} 2, ... 2 _n is sleeve, the sleeve 2 _{1, 2} 2, ... 2 respectively in the _n target unit 3 _1, 3 _2, ... 3 _n, links _{4 1, 4 2, ... 4} n, the measurement unit _{5 1, 5 2, ... 5} n are connected in series. 6 is a cable (with a connector), 7 is a connector for connecting the measuring unit 5 _n and the control device 9, 8 is a wellhead, 9 is a control device, and 10 is a display device.

The wellhead 8 is provided with a control device 9 and a display device 10. The control device 9 receives information from the measurement units 5 ₁ , 5 ₂ ,... 5 _n , processes the information, and displays it on the display device 10. The control device 9 includes an input interface 9A, a CPU (Central Processing Unit) 9B, a storage device 9C, and an output interface 9D connected to the display device 10.

Thus, the measurement system of horizontal directional drilling tip position of the present invention, the target unit 3 _1, 3 _2, ... 3 and _n, the target unit 3 _1, 3 _2, ... 3 _n in via the link supporting mechanism support is, link 4 _1, 4 ₂ having a predetermined link length, ... 4 _n and, the link 4 _1, 4 _2, ... 4 measuring _{units n} is rear end supported through a link supporting mechanism 5 _1, 5 ₂ , ... and 5 _n, the target unit 3 _1, 3 _2, ... 3 _n, the links 4 _1, 4 _2, ... 4 _n and the measurement unit 5 _1, 5 _2, incorporates a ... 5 _n, excavator 1 elastically deformable sleeve 2 ₁ attached to the rear end of, 2 _2, ... 2 and a _n, excavator the sleeve 2 ₁ per progress of drilling by is a link length, 2 _2, ... link passed to two points 2 _n center 4 _1, 4 _2, ... 4 measurement unit angle of _n 5 _1, 5 ₂ , ... 5 _n is azimuth, the direction of gravitational acceleration is converted into coordinates as a reference, the target unit 3 _1, 3 _2, determine the position of ... 3 _n.

  Hereinafter, the components will be sequentially described.

  2 is a plan view of the overall configuration of the underground horizontal excavation tip position measuring apparatus according to an embodiment of the present invention, FIG. 3 is a schematic diagram of a target unit of the underground horizontal excavation tip position measuring apparatus, and FIG. It is a schematic diagram of the measurement unit of the measuring device of the underground horizontal direction excavation tip position.

  In these drawings, 11 is an excavator, 12 is a sleeve tube, 13 is a link, 13A is a link tip (link tip support point), 13B is a link rear end (link rear end support point), and 14 is a control unit 30 and control. A cable 20 connected to the display device is a target unit.

  First, as shown in FIG. 2, this underground horizontal excavation tip position measuring device is composed of the following five parts.

(1) Target Unit As shown in FIG. 3, the target unit 20 is connected to the link 13 and holds the link tip support point 13 </ b> A at the center of the sleeve tube 12 at a certain distance from the measurement unit 30.

(2) Link This link 13 mechanically connects the target unit 20 and the measurement unit 30 and has a sensor function for an inclination angle.

(3) Measurement Unit As shown in FIG. 4, the measurement unit 30 is connected to the link 13 and holds the link rear end support point 13 </ b> B at the center of the sleeve tube 12 at a certain distance from the target unit 20. Further, the inclination angle and azimuth angle of the link 13 are measured.

(4) Sleeve tube The sleeve tube 12 includes the target unit 20, the link 13, and the measurement unit 30, and is attached to the rear end of the excavator 11. As the course of the excavator 1 is changed, the sleeve tube 12 is elastically deformed to generate a link angle. After the excavation is completed, it is collected together with the excavator 11. Moreover, it is desirable that it is made of a material that is difficult to plastically deform.

(5) Control / display device It is set near the pile head (not shown), and the control / measurement signal of the measurement unit 30 is converted into azimuth coordinates. Further, a difference from the planned coordinates is instructed to a display device (not shown).

  Next, the target unit 20 will be further described with reference to FIG.

  The target unit 20 includes a support mechanism 21 for the link 13, and the link support mechanism 21 is provided in a circular ring (case) 22 that fits the inner diameter of the sleeve tube 12 and the ring 22. A bifurcated arm 23 coupled to the link tip support point 13A, a quadrangular link 24 coupled to the arm 23 at a link fulcrum 23A, and a pitch rotating shaft 25 attached to the link 24. Consists of. A rotary encoder (Z axis) 27 for detecting the rotation of the pitch rotation shaft 25 and a rotary encoder (Y axis) 28 for detecting the rotation around the yaw rotation shaft 26 are provided. In this way, the high-resolution rotary encoders 27 and 28 are arranged around each axis.

  As described above, the target unit 20 includes the support mechanism 21 that supports the link 13 so as to allow rotation about the Z and Y axes, and includes the high-resolution rotary encoders 27 and 28 around each axis, and the inclination of the link 13. Measure the corner.

  The target unit 20 has a centering device (not shown) that is adjusted and fixed so that the center of the link 13 and the center of the sleeve tube 12 coincide when installed.

  Next, the measurement unit 30 will be described with reference to FIG.

  The measuring unit 30 includes a circular ring (case) 31 arranged so as to fit the inner diameter of the sleeve tube 12, a pitch rotary bearing 32 fixed to the ring 31, a horizontal holding base 33, and a horizontal holding thereof. An ultrasonic motor 34 as a horizontal holding table driving motor disposed at the rear end of the table 33, a gyrocompass 35 that is installed on the horizontal holding table 33 and measures a true north direction, and inclination sensors 36A and 36B, And a ball screw 37A, a ball screw receiving portion 37B, a joint 38, and a hollow stepping motor 39.

  Further, a link support mechanism 40 is disposed on the pitch rotary bearing mounting portion 47 of the horizontal holding table 33. The link support mechanism 40 includes a bifurcated arm 41 connected to the link rear end support point 13B, a square link 42 fixed so as to be orthogonal to the arm 41 and a link fulcrum 43A, and the link 42 connected to the link 42. The pitch rotation shaft 43 is made up of. A rotary encoder (Z axis) 45 that detects rotation of the pitch rotation shaft 43 and a rotary encoder (Y axis) 46 that detects rotation around the yaw rotation shaft 44 are provided. Thus, high-resolution rotary encoders 45 and 46 are provided around each axis.

  As described above, the measurement unit 30 supports the link support mechanism 40 so that the ring (case) 31 can rotate around the Y and Z axes. In addition, the two tilt sensors 36A and 36B are set with the sensitivity axes directed in the X and Y axis directions so that the horizontal holding table 33 automatically keeps the level.

  Further, the link 13 is supported on the horizontal holding base 33 so as to be rotatable around the Z and Y axes. Further, high-resolution rotary encoders 45 and 46 are provided in the link support mechanism 40 to measure the link rotation angle around each axis.

  The measuring unit 30 has a centering device (not shown) that adjusts and fixes the link 13 and the sleeve tube 12 so that the center of the link 13 coincides with the center of the sleeve tube 12 when the measuring device is assembled.

  Further, the control / display device (not shown) has the following functions.

  (1) The horizontal holding table 33 is controlled to keep the level.

  (2) The gyrocompass 35 is controlled.

  (3) Reading each tilt sensor signal.

  (4) Exchange signals with an external main controller via communication.

  (5) Hold calibration data (tilt sensor offset when horizontal, azimuth angle and device spindle error, etc.).

  Next, the power supply / cable will be described.

Considering usability, it is desirable to mount a battery in the measuring device and not use an external power source and cable. However, this method has the following problems.
(1) There is a possibility of running out of battery for several days or more in the ground.
(2) Furthermore, since there are mechanical drive units such as a horizontal holding base and a gyrocompass, power consumption is large.
(3) In the unlikely event that the battery runs out, it is difficult to recover the device.

  In view of the above, at present, operation using only a battery involves risks.

Therefore, pay attention to the following points when supplying energy using an external power supply and cable.
(1) It is necessary to pass the cable through the sleeve tube. For this reason, it is necessary to connect and extend the cable for every fixed length of the sleeve tube, and therefore a connector for connection is used.
(2) Arrange the cable and the hydraulic hose for the excavator so as not to get entangled in the sleeve tube.
(3) Check to maintain the reliability of a large number of cables.

Therefore, the following method can be considered for actual power supply.
(1) Composite hose: A hose that integrates a hydraulic hose for an excavator and a power cable for a measuring device together. At the end of this composite hose, a hydraulic hose and a power cable are separated, and a hydraulic one-touch coupler and an electrical connector are attached, respectively. The electrical connector is preferably IP67 waterproof. In addition to the power supply, this connector is equipped with a communication terminal (about 4 poles) to communicate with the control / display device.
(2) Hydraulic motor generator: A generator driven by a hydraulic motor is built in the measuring device so that the battery can be charged. The hydraulic pressure branches from the hydraulic motor drive circuit of the excavator and is supplied to the power generation hydraulic motor via the pressure reducing valve. Communication with the control / display device is performed by radio waves or ultrasonic waves using a sleeve tube as a duct.

  FIG. 5 is an explanatory diagram of the principle of measurement by the underground horizontal excavation tip position measuring device according to the embodiment of the present invention, FIG. 6 is a schematic diagram of the main mechanism of the underground horizontal excavation tip position measuring device, FIG. 7 is a schematic diagram showing the positional relationship of each unit at the time of position update in the measurement device for the horizontal horizontal excavation tip position, and FIG. 8 shows the rotation direction detection by the gyrocompass of the measurement device for the horizontal horizontal excavation tip position. FIG. 9 is an explanatory diagram of a signal processing method for detecting the rotation direction.

Here, the pipe propulsion method satisfies the following conditions.
(1) Along with the progress of excavation by the excavator, the sleeve tube and the measuring device advance by the length of the tube fed on the ground side.
(2) The pipe that is fed subsequently follows the trajectory dug by the excavator.

  Based on the above, first, the principle of measurement will be described.

  As shown in FIG. 5, the angle of the link 13 passed to two points at the center of the sleeve tube 12 is converted into coordinates based on the azimuth angle and the gravitational acceleration direction, and the position of each point of the sleeve tube 12 is obtained.

  (1) Measurement is performed for each length l of the link 13.

  (2) The direction of the gravity vector is obtained by the inclination sensors 36A and 36B.

  (3) The azimuth angle is obtained by observing the rotation axis of the earth using the gyrocompass 35. At the position where the excavation has advanced by the link length, the azimuth angle of the target unit 20 one sample before, By utilizing the fact that the azimuth angle of the measurement unit 30 in the next sample is equal, the number of detections of the azimuth angle can be reduced.

  (4) The horizontal holding table 33 is provided in the measurement unit 30, and the inclination sensors 36 </ b> A and 36 </ b> B and the gyrocompass 35 are arranged on the horizontal holding table 33.

  (5) The target unit 20 and the measurement unit 30 are connected by a link 13. The pitch rotation shaft 43 on the measurement unit 30 side is attached to the pitch rotation bearing mounting portion 47 of the horizontal holding table 33, and the angle formed with the horizontal holding table 33 is measured by the rotary encoders 45 and 46.

  (6) The target unit 20 and the measurement unit 30 are mounted in the same sleeve tube 12.

  FIG. 6 is a schematic view of a measuring apparatus for the position of the underground horizontal excavation tip according to the present invention.

  Next, the position / azimuth angle of the target unit will be described with reference to FIG.

  (1) Mount the target unit 20 on the rear end of the excavator 11 by moving the measurement unit 30 first.

  (2) The horizontal holding table 33 feeds back signals from the tilt sensors 36A and 36B so as to always keep the level automatically.

In the sample i at a certain position, the north direction is measured from the detection of the earth rotation axis by the gyrocompass 35, and the main axis (A) azimuth (azimuth angle of the horizontal holding table 33) ψ _Bi of the measurement unit 30 is obtained.

(3) The position ^B P _Ai of the link fulcrum 23A of the target unit 20 viewed from the measurement unit spindle (A) is represented by the following formula (1).

However, R _zi and R _yi are rotational transformation matrices around the z ′ and y ′ axes, and are as follows.

Here, a _i is the pitching angle of the link 13 with respect to the horizontal holding table 33, b _i is the yaw angle of the link 13 with respect to the horizontal holding table 33, c _i is the pitching angle of the link 13 with respect to the main axis (B) of the target unit 20, and d _i represents the yaw angle of the link 13 with respect to the main axis (B) of the target unit 20.

The azimuth angle of the target unit 20 is
ψ _Ai = ψ _Bi + b _i + d _i (3)
When the position ^B P _Ai of the link fulcrum 23A of the target unit 20 is expressed by the coordinates with the azimuth coordinate and the excavation start position as the origin, the following equation (4) is obtained using the above equation (1).

Further, P _Bi is the position of the link fulcrum 43A of the measurement unit 30 expressed in the azimuth reference coordinates, and P _B0 is the origin where excavation is started.

  When the above formulas (2) and (5) are substituted into the above formula (4) and rearranged, the coordinates of the target unit 20 expressed in the azimuth coordinate system become the formula (6).

  Next, updating of the underground horizontal excavation tip position will be described.

  FIG. 7 is an explanatory diagram of updating the position. Here, 13, 13 'and 13 "are links, 15 is sample i, 15' is sample i + 1, 15" is sample i + 2, 16 is the target unit of sample i, 16 'is the target unit of sample i + 1, and 16 "is A target unit for sample i + 2, 17 is a measurement unit for sample i, 17 ′ is a measurement unit for sample i + 1, and 17 ″ is a measurement unit for sample i + 2.

  The measured value at the position where the excavator has advanced excavation and has advanced from the position of the sample i (15) by the length l of the link 13 is the measured value of the sample i + 1 (15 ′). At this time, the position of the link fulcrum of the measurement unit 17 'of the sample i + 1 coincides with the position of the link fulcrum of the target unit 16 of the sample i.

Thus, the position and azimuth angle of the measurement unit 17 'in the sample i + 1 (15') are the same as the position and azimuth angle of the target unit 16 in the sample i (15) as shown in FIG. Therefore,
ψ _{Bi + 1} = ψ _Ai , P _{Bi + 1} = P _Ai (7)
Similar to equation (3) above,

  From the above formulas (7) and (8), the link fulcrum position of each sample expressed in the azimuth reference coordinates with the excavation start position as the origin is sequentially obtained.

However, errors accumulate in the azimuth angles ψ _A and ψ _B obtained by the above method, and this error has a great influence on accuracy. In order to maintain accuracy, the excavation is temporarily stopped for about 10 minutes at appropriate intervals, and the azimuth angle of the measurement unit 30 is detected by the gyrocompass 25 and used as the azimuth angle ψ _B at that time.

  Thereafter, the azimuth is corrected by the same calculation procedure, and the accuracy is maintained.

  Next, azimuth angle detection will be described.

  Generally, (1) gyro compass, (2) geomagnetic sensor, (3) GPS compass, etc. can be considered as azimuth angle detection means. In the sensor, accuracy is not guaranteed in a place where a substance that disturbs geomagnetism is assumed, such as pipes and reinforcing bars, and the GPS compass (3) described above cannot receive radio waves from a satellite. For this reason, in the present invention, the gyro compass 25 is selected.

  The gyrocompass 25 detects the direction of the rotation axis of the earth using a highly accurate angular velocity sensor, and is used in the field of aircraft and the like.

Since the rotation angular velocity of the earth is a small value of about 4.17 × 10 ⁻³ (deg / sec), high accuracy is required for the angular velocity sensor, and an optical fiber gyro is usually used.

  FIG. 8 is an explanatory diagram of detection of the rotation direction by the gyrocompass showing an embodiment of the present invention.

  As shown in this figure, an angular velocity sensor (optical fiber gyroscope) is installed as a gyrocompass 35 on the horizontal holding table 33. In addition, 51 is a vertical axis with respect to the horizontal holding base 33, 52 is an angular velocity detection axis, and 53 is a ground axis.

  As described above, when the gyrocompass (angular velocity sensor) 35 is placed on the rotating horizontal holding base 33 and rotated around the vertical axis 51, the sensitivity axis of the gyrocompass (angular velocity sensor) 35 faces the vicinity of the rotation axis of the earth. And the output becomes large, and when orthogonal, the output disappears. Using this property, the azimuth angle with respect to true north can be obtained from the correlation between the rotation axis with respect to the reference coordinate axis of the apparatus and the output.

  Next, signal processing in the rotation direction by the gyrocompass of the present invention will be described with reference to FIG.

  As described above, when the angular velocity sensor 35 that rotates around the vertical axis 51 is installed on the horizontal holding base 33 that always keeps the level, the relationship between the rotation angle and the angular velocity sensor 35 becomes a sine wave that takes a maximum value at true north. . By calculating the angle at which the correlation function with the sensor output is maximized using this as a reference signal, the angle difference between the reference axis of the apparatus and true north, that is, the azimuth angle is obtained.

  The drawback of this method is that it is necessary to average the long-time data to increase the reliability in order to determine the azimuth from the small output signal, and the measurement time becomes long. Further, it is not preferable to give vibration to the angular velocity sensor 35 during measurement. For this reason, it is difficult to always measure the absolute azimuth angle.

Next, an operation method will be described.
[1] For angle calibration, the apparatus of the present invention is placed on a horizontal table with a known azimuth, and the azimuth angle output from the gyrocompass 35 and the angle of each encoder are recorded in the EEPROM in the measurement apparatus as the origin.
[2] The device is attached to the rear end of the excavator 11 with the target unit 20 facing forward, and placed in a pile.
[3] The origin coordinate P _B0 and the direction measurement period are input to the control / display device, and measurement is started.
[4] After starting the measurement, the azimuth measurement is performed to obtain the initial azimuth ψ _B0 of the measurement unit 30.
[5] Next, the azimuth angle / coordinates ψ _A0 , P _A0 of the target unit 20 are obtained by the above formulas (3) and (6).
[6] The coordinates of the target unit 20 are displayed on the display device 9.
[7] Excavation is performed for the length of one link 13.
[8] The azimuth angle ψ _Bi and the coordinate P _Bi of the measurement unit 30 are obtained by the above equation (7).
[9] The azimuth angle ψ _Ai and coordinates P _Ai of the target unit 20 are obtained from the above equations (3) and (4).
[10] Repeat [5] to [9] until the azimuth measurement period is reached.

  Next, main parts of the measuring apparatus will be described.

(1) Inclination sensor JA-23-MA-00 (servo type, manufactured by Japan Aviation Electronics, measurement range ± 90 °, angular resolution 10 seconds, temperature range −25 to 70 ° C.) is suitable.

(2) Angle detector It is considered that a high resolution is required in consideration of the slight deflection of the sleeve tube and the detection accuracy directly related to the overall performance. In addition, since the measurement takes a long time and the origin may be lost, an absolute type that can reliably manage the origin is desirable. As candidate parts, RA510 (Sony Precision: resolution 2.5 seconds), SA35 (Tamakawa Seiki: resolution 10 seconds), etc. are used.

(3) Motor for driving the horizontal holding stand Considering that the moving speed is small and precise feeding is required and holding torque is required, it is considered that an ultrasonic motor or a stepping motor with a harmonic reduction gear is suitable. When an ultrasonic motor is used, the life is about 1000 hours (actual operation time), and therefore it is necessary to replace it periodically.

  Since the Y axis is driven by a ball screw or the like, it is necessary to provide a mechanism for eliminating backlash when the motor cannot be directly connected to the ball screw.

(4) Gyrocompass Since it is a special part, there are few choices, but JM77 manufactured by Japan Aviation Electronics Industry Co., Ltd. can be used as an example of a commercially available unit. When producing a turntable, it is considered that an optical fiber gyro JG-201FA manufactured by Japan Aviation Electronics Corporation can be used. Since the output is very weak, it is necessary to take sufficient measures against noise in the amplification system.

  The drive of the turntable must suppress uneven speed. In addition, since the operation time becomes long, an AC servo motor is suitable from the viewpoint of reliability.

  Next, a measurement method that omits the horizontal holding table of the horizontal system underground position measuring apparatus will be described.

  In the said Example, the method of using a horizontal holding stand was employ | adopted in order to obtain | require an azimuth from a ground axis in the measurement system of a horizontal system underground position measuring apparatus. Although this method is reliable, the structure is complicated and the difficulty of manufacturing the device is high. Therefore, in this embodiment, a data processing method that does not require a horizontal holding table has been devised.

(1) Principle of measurement (1-1) Azimuth angle measurement The orthogonal coordinate with the main axis of the measuring device as the x axis is the A coordinate system, the coordinate with the true north as the x 'axis and the vertical as the z' axis is the B coordinate system , B coordinates are rotated around the y ′ axis, and the coordinates where x ″ coincides with the ground axis are defined as the C coordinate system.

  The relationship of this coordinate system is shown in FIG.

  In FIG. 10A, 61 is a measurement unit, 62 is an x-axis, 63 is a y-axis, 64 is a z-axis, 65 is a north axis (x 'axis), and 66 is a y' axis.

  In FIG. 10B, 67 is the ground axis (x ″ axis), and 68 is the z ″ axis.

As shown in FIG. 11, rotates the sensitivity axis of the high-precision gyro compass 35 in the x-y plane of the A coordinate system, the trajectory ^A V to this sensitive axis draws the formula (9) in the A coordinate system .

^A V = [cos θ sin θ 0] ^t (9)
However, (theta) has shown the angle which the measuring apparatus principal axis and the sensitivity axis | shaft of a gyrocompass make.

  When this trajectory is expressed in the B coordinate system, Equation (10) is obtained.

^B V = R _z R _y R _x ^A V (10)
R _z , R _y , and R _x are coordinate transformation matrices from the A coordinate to the B coordinate, and are represented by the following equations (11) to (13).

Where α is the tilt angle in the x-axis direction, β is the tilt angle in the y-axis direction, and ψ is the azimuth angle of the apparatus main axis. When the latitude of the measurement point is L, the locus ^C V gyrocompass sensitivity axis when viewed from the C coordinate system becomes Equation (14).

^C V = R _L ^B V
= R _L R _z R _y R _x ^A V (14)
R _L is a transformation matrix from B coordinates to C coordinates, and is given by equation (15).

^If the x component of CV is E, then equation (16) is obtained from equation (14).

E (θ) = (cosLcosψcosα + sinLsinα) cosθ
+ {-CosLsinψcosβ + (cosLcosψsinα
-SinLcosα) sinβ} sinθ (16)
On the other hand, since E represents the sensitivity of the gyrocompass with respect to the earth rotation angular velocity, it is obtained from the output of the gyrocompass at the rotation angle θ by the equation (17).

E = ω (θ) / ω ₀ (17)
However, ω (θ) represents the angular velocity detected by the gyrocompass, and ω ₀ represents the rotation angular velocity of the earth.

  When θ = 0, the second term of Expression (16) becomes 0, and therefore Expression (18) is obtained using sensitivity E (0) calculated from the gyrocompass output at this time.

E (0) = cosLcosψcosα + sinLsinα (18)
Therefore, the azimuth angle ψ of the main axis of the measuring device is expressed by Equation (19).

  There are two solutions of Equation (19) between −π and π. For this reason, the one close to ψ of the two solutions is adopted. Therefore, it is necessary to give a rough initial azimuth at the start of measurement.

  When calculating the arc cosine, a normal computer library calculates only the main value between 0 and π, so it is determined which ± ψ is closer to the previous ψ with respect to the solution of the equation (19). adopt.

(1-2) Noise Elimination Expression (19) shows that the azimuth angle can be obtained from observation of one point, but the actual gyrocompass output includes error factors such as offset error, gain error, and noise component. Therefore, these are removed as follows.

  From sin (−θ) = − sin (θ), when equation (16) is added to two points symmetrical with respect to θ = 0, the second term is eliminated, and equation (20) is obtained.

  The selection of the two solutions obtained by Expression (20) is the same as that of Expression (19).

  Assuming that the noise is Gaussian, it is removed by averaging a sufficient number of samples, so the azimuth angle ψ is given by equation (21) for a sufficiently large n.

(1-3) Offset removal As described above, the output of the gyrocompass is expected to include an offset. In order to remove the offset, E in equation (17) is obtained as follows.
(A) The gyrocompass is rotated a sufficient number of times, and the average of the output with respect to the rotation angle is obtained.
(B) The average of one period is calculated from the above (a), and is subtracted from each element, and E is calculated by Expression (17).

(1-4) Gain Error Correction In the method of this embodiment, the gain error becomes the azimuth error, unlike the previous embodiment in which the azimuth angle is obtained from the correlation function. For this reason, at the time of calibration, the gain is corrected as follows.

  (A) On a horizontal calibration table with known azimuth and latitude, turn the gyrocompass a sufficient number of times, turning the measuring unit spindle to true north, assuming a gain of 1, and calculate E as described in (1-3) Let A be the total amplitude.

  (B) In Equation (16), a = b = 0, and the total amplitude of E is obtained and set to B.

  (C) B / A is recorded in the ROM of the measuring device as the gain of the gyrocompass.

  (D) During measurement, E is corrected with the gain obtained in (c) above.

(2) Measurement of link position (2-1) Position / azimuth angle of target unit FIG. 12 is a schematic diagram of a measurement unit of a measuring apparatus for a horizontal horizontal excavation tip position according to another embodiment of the present invention. The link and the target unit are the same as those in the above-described embodiment, and are not shown here.

  In this figure, reference numeral 70 denotes a measuring unit. The measuring unit 70 includes a base 71, a gyrocompass 72 disposed on the base 71, tilt sensors 73 </ b> A and 73 </ b> B, and a pitch rotary bearing mounting portion 74. Further, a link support mechanism 80 is disposed on the pitch rotary bearing mounting portion 74 of the base 71. The link support mechanism 80 includes a bifurcated arm 81 connected to the link rear end 13B, a rectangular link 82 fixed so as to be orthogonal to the arm 81, and a pitch rotation shaft 83 connected to the link 82. Consists of. A rotary encoder (Z axis) 85 that detects rotation of the pitch rotation shaft 83 and a rotary encoder (Y axis) 86 that detects rotation around the yaw rotation shaft 84 are provided. Thus, high-resolution rotary encoders 85 and 86 are provided around each axis.

  In this measurement unit 70, the coordinate system fixed to the measurement unit main axis is A, the true north is the x axis, the upper is the z axis, and the coordinate system having the excavation start point as the origin is B.

Therefore, the link support position ^A P _Ai the target unit looking from the measuring unit 70 is given by equation (22).

Here, R _zi and R _yi are rotational transformation matrices around the z ′ and y ′ axes and are as follows.

The direction vector ^A V of the measuring unit 70 as viewed from the target unit axis is a formula (24).

Here, a _i is the pitching angle of the link 13 with respect to the measurement unit main axis, b _i is the yaw angle of the link 13 with respect to the measurement unit main axis, c _i is the pitching angle of the link 13 with respect to the target unit main axis, and d _i is the target unit of the link 13. The yaw angle with respect to the main axis.

Assuming that the pitching angle of the measurement unit main axis is α _i , the roll angle is β _i , and the azimuth angle is ψ _i , the link support position coordinates P _Ai of the target unit expressed in the azimuth coordinate system B and the direction vector V _A of the target unit are (27) and (28).

The azimuth angle of the target unit main axis is expressed by equation (30) using the x and y axis components V _Ax and V _Ay of the direction vector V _A.

  The problem of the main value of the inverse sine function is the same as that in the azimuth angle measurement in equation (30).

(2-2) Position Update FIG. 13 is a schematic diagram showing the positional relationship between a measurement unit and a target unit according to another embodiment of the present invention. Here, 91 is sample i, 91 ′ is sample i + 1, 91 ″ is sample i + 2, 92 is sample i target unit, 92 ′ is sample i + 1 target unit, 92 ″ is sample i + 2 target unit, and 93 is sample i. , 93 ′ is a measurement unit for sample i + 1, and 93 ″ is a measurement unit for sample i + 2.

  The measured value at the position that is excavated by the excavator and advanced from the position of the sample i (91) by the link length l is taken as the measured value of the sample i + 1 (91 '). At this time, the link fulcrum position of the measurement unit 93 ′ of the sample i + 1 is at the link fulcrum position of the target unit 92 of the sample i.

  Therefore, as shown in FIG. 13, the position / azimuth angle of the measurement unit 93 ′ in the sample i + 1 is equal to the position / azimuth angle of the target unit 92 in the sample i, and the equation (31) is established.

ψ _{Bi + 1} = ψ _Ai , P _{Bi + 1} = P _Ai (33)
Using the relationships of the above formulas (25), (26), (30), and (31), the link support position coordinates of each sample represented by the azimuth reference coordinates with the excavation start position as the origin can be obtained sequentially.

However, errors accumulate in the azimuth angles ψ _A and ψ _B obtained by the above method, and this error has a great influence on accuracy. In order to maintain accuracy, excavation is temporarily stopped for about 10 minutes at appropriate intervals, and the azimuth angle of the measurement unit 70 is detected by the gyrocompass 72 and used as the azimuth angle ψ _B at that time.

  Thereafter, the azimuth is corrected by the same calculation procedure, and the accuracy is maintained.

(3) Difference due to the presence or absence of a horizontal holding base In the method using the horizontal holding base described above, the sensitivity axis of the gyrocompass rotates in parallel with the horizontal plane. It becomes minimum when the sensitivity axis faces true north, and at the same time, the output of the gyro compass becomes maximum. Therefore, assuming that the rotation angle of the gyrocompass is θ, the output of the gyrocompass is E (θ), θ that maximizes the correlation function of cos (θ) and E (θ) can be set as the azimuth angle. In this correlation function method, since the phase difference between two signals is obtained, the offset error and gain error of the gyrocompass do not affect the calculation of θ.

  On the other hand, in the configuration in which the horizontal holding base of this embodiment is omitted, the sensitivity axis of the gyrocompass rotates while tilting with respect to the horizontal plane, so the angle formed between the earth rotation axis and the sensitivity axis of the gyrocompass is minimized. The direction is not necessarily true north. For this reason, the azimuth angle cannot be obtained from the phase difference between the reference function and the measurement signal.

  On the other hand, since the inclination of the rotation axis of the gyrocompass can be easily obtained by a tilt sensor, the magnitude of the output when the sensitivity axis of the gyrocompass is directed to a certain azimuth angle by referring to the latitude of the measurement location is expressed by the above equation (16 ), And the azimuth angle can be obtained by the above equation (20) from comparison with the actually measured output.

  The above equation (20) is an equation for obtaining the azimuth angle from the magnitude of the output of the gyrocompass, and is strongly influenced by the gain error and the offset error. This is different from the method of obtaining the azimuth angle by the phase difference, and the demand for the stability of the measurement system is increased.

  On the other hand, the configuration of the apparatus is greatly simplified, and there are advantages that cost reduction can be expected and that it is easy to ensure mechanical accuracy.

  In addition, this invention is not limited to the said Example, Based on the meaning of this invention, a various deformation | transformation is possible and these are not excluded from the scope of the present invention.

  The horizontal excavation tip position measuring apparatus of the present invention is suitable for use in measuring the horizontal horizontal excavation tip position in horizontal excavation such as a pipe having a relatively small diameter.

1 is an overall configuration diagram of a measurement system for an underground horizontal excavation tip position according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the entire configuration of a measuring device for a ground horizontal direction excavation tip position according to an embodiment of the present invention. It is a schematic diagram of the target unit of the measuring device of the underground horizontal excavation tip position showing an embodiment of the present invention. It is a schematic diagram of the measurement unit of the measuring device of the underground horizontal excavation tip position showing an embodiment of the present invention. It is explanatory drawing of the measurement principle by the measuring apparatus of a horizontal horizontal excavation tip position which shows the Example of this invention. It is a schematic diagram of the main mechanism of the measuring apparatus of the underground horizontal direction excavation tip position which shows the Example of this invention. It is a schematic diagram which shows the positional relationship of each unit at the time of the position update in the measuring apparatus of the underground horizontal excavation tip position which shows the Example of this invention. It is explanatory drawing of rotation direction detection by the gyrocompass of the measuring apparatus of the underground horizontal direction excavation tip position which shows the Example of this invention. It is explanatory drawing of the signal processing method of the rotation direction detection by the gyrocompass of the measuring apparatus of the underground horizontal direction excavation tip position which shows the Example of this invention. It is a figure which shows the relationship of the coordinate system which shows the other Example of this invention. It is a figure which shows the state which rotated the sensitivity axis of the high precision gyro which shows the other Example of this invention to the xy plane of A coordinate system. It is a schematic diagram of the measuring unit of the measuring apparatus of the underground horizontal direction excavation tip position showing another embodiment of the present invention. It is a schematic diagram which shows the positional relationship of the measurement unit and target unit which show the other Example of this invention.

Explanation of symbols

1,11 excavator _{2 1, 2 2, ... 2} n, 12 sleeve _{3 1, 3 2, ... 3} n, 20 target unit _{4 1, 4 2, ... 4} n, 13,13 ', 13 " link 5 ₁ , 5 ₂ ,... 5 _n , 30, 61, 70 Measuring unit 6 Cable (with connector)
7 Connector 8 Wellhead 9 Control Device 9A Input Interface 9B CPU (Central Processing Unit)
9C Storage device 9D Output interface 10 Display device 13A Link front end support point 13B Link rear end support point 14 Cable 15, 91 Sample i
15 ', 91' sample i + 1
15 ″, 91 ″ sample i + 2
16, 92 Target unit of sample i 16 ', 92' Target unit of sample i + 1 16 ", 92" Target unit of sample i + 2 17, 93 Measurement unit of sample i 17 ', 93' Measurement unit of sample i + 1 17 ", 93 ″ Sample i + 2 measurement unit 21, 40, 80 Target unit link support mechanism 22, 31 Circular ring (case)
23, 41, 81 Bifurcated arm 23A, 43A Link fulcrum 24, 42, 82 Square link 25, 43, 83 Pitch rotation axis 26, 44, 84 Yaw rotation axis 27, 45, 85 Rotary encoder (Z axis)
28, 46, 86 Rotary encoder (Y axis)
32 Pitch rotary bearing 33 Horizontal holding table 34 Ultrasonic motor 35, 72 Gyrocompass (angular velocity sensor)
36A, 36B, 73A, 73B Inclination sensor 37A Ball screw 37B Ball screw receiving part 38 Joint 39 Hollow stepping motor 47, 74 Pitch rotary bearing mounting part 51 Vertical axis for horizontal holding base 52 Angular velocity detection axis 53 Ground axis 62 x axis 63 y axis 64 z axis 65 North axis (x 'axis)
66 y 'axis 67 Ground axis (x "axis)
68 z ″ axis 71 base

Claims (14)

  A target unit, a measurement apparatus comprising a link supported by the target unit via a link support mechanism and having a predetermined link length, a measurement unit supported by a rear end of the link via a link support mechanism, and the target unit, The link and the measurement unit are built in, and an elastically deformable sleeve tube attached to the rear end of the excavator is provided, and at the two points of the sleeve tube each time the amount of excavation by the excavator becomes the link length A horizontal excavation tip position measuring system, wherein the passed link angle is converted by the measuring unit into coordinates based on an azimuth angle and a gravitational acceleration direction to determine the position of the target unit.   2. The horizontal excavation tip position measuring system according to claim 1, wherein the sleeve tube is elastically deformed along a course change of the excavator during excavation, and the target unit has a relative angle between the position of the measurement unit and the link. A system for measuring the position of a horizontal excavation tip, characterized by measuring the position of the horizontal drilling.   2. The horizontal excavation tip position measurement system according to claim 1, wherein the measurement unit includes an inclination sensor and a gyrocompass disposed on a horizontal holding table, and obtains an angle of the link with reference to gravitational acceleration and an earth rotation axis. The horizontal excavation tip position measuring system for measuring the position of the target unit.   The horizontal excavation tip position measurement system according to claim 3, wherein an azimuth angle is measured using the gyrocompass.   4. The horizontal excavation tip position measurement system according to claim 3, wherein the measurement unit is provided with a link support mechanism so that the link can rotate about the Z and Y axes with respect to the horizontal holding table. The horizontal excavation tip position measuring system is characterized in that a high-resolution rotary encoder is provided to measure link rotation angles around the Z and Y axes.   4. The horizontal excavation tip position measuring system according to claim 3, wherein the measurement unit sets two inclination sensors with the sensitivity axes in the X and Y axis directions, and the horizontal holding table automatically A horizontal excavation tip position measuring system characterized by maintaining a level.   2. The horizontal excavation tip position measurement system according to claim 1, wherein the target unit is connected to a link, and a link support point is held at the center of the sleeve tube at a predetermined distance from the measurement unit. Directional drilling tip position measurement system.   The horizontal excavation tip position measurement system according to claim 1, wherein the target unit includes a link support mechanism so as to allow rotation about the Z and Y axes, and includes a high-resolution rotary encoder around each axis. A horizontal excavation tip position measuring system characterized by measuring an inclination angle of a link.   2. The horizontal excavation tip position measurement system according to claim 1, wherein the position and direction of the measurement unit are considered to coincide with the position and direction of the target unit before the measurement apparatus moves the same distance as the length of the link. The horizontal excavation tip position measuring system, characterized in that the number of azimuth angle measurements can be reduced by means of.   2. The horizontal excavation tip position measurement system according to claim 1, wherein the measurement unit arranges an inclination sensor and a gyrocompass on a base and determines a position of the target unit by a correction method that refers to the latitude of the measurement point. A horizontal excavation tip position measuring system characterized by measuring.   11. The horizontal excavation tip position measurement system according to claim 10, wherein the measurement unit is provided with a link support mechanism so that the link can rotate around the Z and Y axes with respect to the base. A horizontal excavation tip position measuring system characterized by providing a high-resolution rotary encoder and measuring link rotation angles around the Z and Y axes.   11. The horizontal excavation tip position measurement system according to claim 10, wherein the target unit is connected to a link, and a link support point is held at the center of the sleeve tube at a predetermined distance from the measurement unit. Directional drilling tip position measurement system.   11. The horizontal excavation tip position measurement system according to claim 10, wherein the target unit includes a link support mechanism so as to allow rotation about the Z and Y axes, and includes a high-resolution rotary encoder around each axis. A horizontal excavation tip position measuring system characterized by measuring an inclination angle of a link.   11. A horizontal excavation tip position measurement system according to claim 10, wherein the position of the measurement unit is assumed to coincide with the position of the target unit before the measurement device has moved the same distance as the length of the link. A horizontal excavation tip position measuring system characterized in that the number of times can be reduced.

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