APPARATUS AND METHOD FOR DETERMINING POSITION OF DRILLING TOOL DURING DRILLING

Abstract

An apparatus and method of determining position of a drilling tool during drilling is disclosed. The apparatus includes a magnetic source mounted to a rotating drilling tool and at least three magnetometers, which are located outside a drilled hole. Sensing data of the rotating magnetic field is transmitted from the magnetometers to a control unit (CU) provided with a position calculation algorithm. The control unit is also provided with pose data of the magnetometers. The control unit compares the received sensing data and determines phase angles from the sensing data. The algorithm utilizes the phase angles and the known positions of the magnetometers when calculating the position.

Claims

1. An apparatus for detecting change of position of a drilling tool of a rock drilling rig during drilling when the drilling tool is rotated around its longitudinal drilling axis, the apparatus comprising: at least one magnetic source mounted to the rotatable drilling tool and configured to generate rotating magnetic field, and wherein direction of axis of the magnetic field deviates from the drilling axis; at least one magnetometer configured to sense the magnetic field generated by the magnetic source; and at least one control unit configured to receive sensing data from the magnetometers and is configured to examine the rotating magnetic field; and at least three magnetometers, which are all located external relative to the drilling tool, wherein the control unit is provided with data on position and orientation of the magnetometers, wherein the control unit is configured to detect phase differences between the sensing data received from the magnetometers, determine phase angles between the magnetometers and the rotating magnetic source in response to the detected phase differences, and calculate data on a position of the magnetic source on the basis of the detected phase angles and the input positions and orientations of the magnetometers, and wherein the control unit is further provided with data on advanced distance of the magnetic source inside the drilled hole, the control unit being configured to calculate three dimensional position data of the drilling tool using the calculated data on position of the magnetic source and the data on the advance distance.

2. The apparatus as claimed in claim 1, wherein the control unit is configured to implement triangulation in the position calculation of the magnetic source.

3. The apparatus as claimed in claim 1, wherein the control unit is configured to examine the received sensing data by determining maximum strengths of the received magnetic field values and to determine corresponding rotation angle of the magnetic source relative to the examined magnetometer; and the control unit is configured to determine the phase angles between the sensing data by comparing the determined rotation angles of the detected maximum strength values.

4. The apparatus as claimed in claim 1, wherein the magnetometers are located on a rock surface surrounding the drill hole being drilled.

5. The apparatus as claimed in claim 1, wherein the control unit is provided with sensing data from the magnetometers at several measuring points locating at different advance distances of the magnetic source inside the drilled hole, and the control unit is configured to compare the calculated position data of the several measuring points and is configured to determine bending of the drilling tool in response to detected deviations in the position data.

6. The apparatus as claimed in claim 1, wherein the control unit is provided with data on coordinates of the magnetometers in a work site coordinate system, and the control unit is configured to calculate coordinates of the magnetic source in the work site coordinate system.

7. The apparatus as claimed in claim 1, wherein the control unit is provided with a processor configured to execute a position detection algorithm, an execution of which is configured to calculate the position of the magnetic source in response to the received sensing data of the magnetometers and the input position data.

8. The apparatus as claimed in claim 1, wherein the control unit is configured to execute the position determination without comparing strength of the detected magnetic fields.

9. The apparatus as claimed in claim 1, wherein the magnetic source is a permanent magnet.

10. The apparatus as claimed in claim 1, wherein the magnetic source is mounted to a drill bit locating at a distal end of the drilling tool.

11. A rock drilling rig, comprising: a movable carrier; at least one drilling boom connected movably to the carrier and equipped with a rock drilling unit, the rock drilling unit including a feed beam and a rock drilling machine supported movably on the feed beam; and at least one apparatus according to claim 1 arranged to determine a position of the drilling tool connectable to the drilling unit.

12. A method of determining position of a drilling tool of a rock drilling rig during drilling operation, the method comprising: rotating the drilling tool around its longitudinal drilling axis during drilling and feeding of the drilling tool axially forward in an advance direction; detecting a position of the drilling tool during the drilling by means of an apparatus having at least one magnetic source mounted to the rotating drilling tool and at least one magnetometer; generating a rotating magnetic field by rotating the magnetic source together with the drilling tool; sensing the rotating magnetic field by means of the at least one magnetometer and producing sensing data; implementing at least three magnetometers in the sensing and generating at least three sensing data; executing a comparison between the generated sensing data and determining phase differences and phase angles; and calculating a position of the magnetic source relative to known poses of the magnetometers (12a-12c) on a basis of the determined phase angles, wherein a control unit is configured to receive the sensing data from the magnetometers and further provided with data on an advanced distance of the magnetic source inside the drilled hole; and the control unit is configured to calculate three dimensional position data of the drilling tool using the calculated data on a position of the magnetic source and the data on the advance distance.

13. The method as claimed in claim 12, further comprising: sensing an advanced distance of the magnetic source inside the drilled hole during the drilling; repeating the position measurement at several measuring points having different depths in the drill hole; and comparing the calculated positions of the drilling tool at the several measuring points and determining straightness of the drill hole in response to the comparison.

14. A computer program product comprising program code means configured to execute the method of claim 12 when being run on a computer or a data processing device.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0068] FIG. 1 is a schematic side view of a rock drilling rig.

[0069] FIG. 2 is a schematic diagram presenting components of the disclosed apparatus.

[0070] FIG. 3 is a schematic side view of a drilling tool and its components provided with magnetic sources.

[0071] FIG. 4 is a schematic side view of a drilling tool at a bottom of a drill hole.

[0072] FIG. 5 is a schematic side view of a magnetic source surrounded by a non-ferromagnetic protection material.

[0073] FIG. 6 is a schematic diagram showing a control unit intended for executing position detection.

[0074] FIG. 7 is a highly simplified schematic view showing a principle of triangulation utilized in the disclosed measuring system.

[0075] FIG. 8 is a schematic top view of a measuring arrangement having three magnetometers and a magnetic source mounted to a rotating drilling tool.

[0076] FIGS. 9a and 9b are schematic diagrams relating to FIG. 8 and demonstrating calculation of the initial position and the changed position of the drilling tool.

[0077] FIG. 10 is a schematic graph of magnetic field measurements taken by two magnetometers and determination of a phase angle.

[0078] FIG. 11 is another schematic graph of magnetic field measurements taken by two other magnetometers and determination of a phase angle.

[0079] FIG. 12 is a schematic view showing that magnetometers may be positioned at different distances and directions from a drill hole.

[0080] FIG. 13 is a schematic side view of a measuring arrangement for detecting drill hole straightness.

[0081] FIG. 14 is a schematic side view showing an alternative mounting arrangement for the magnetometers.

[0082] For the sake of clarity, the figures show some embodiments of the disclosed solution in a simplified manner. In the figures, like reference numerals identify like elements.

DETAILED DESCRIPTION

[0083] FIG. 1 shows a rock drilling rig 1 for drilling drill holes 2. The rock drilling rig 1 includes a movable carrier 3 and one or more drilling booms 4 connected to the carrier 3. The drilling boom 4 is provided with a drilling unit 5 having a feed beam 6 and a rock drilling machine 7 supported movably on it. A drilling tool 8 is connectable to the rock drilling machine 7 and may be rotated in a direction R around drilling axis 9 by means of a rotation device of the rock drilling machine 7.

[0084] At a distal end of the drilling tool 8 is a drill bit 10. The rock drilling machine 7 may include a percussion device for generating impact pulses to the drilling tool 8. The percussion device may be located either in connection with the drilling machine 7 or at a distal end portion of the drilling tool, whereby the percussive rock drilling may be top hammer drilling or down-the-hole drilling. A further alternative is that the drilling is rotary drilling without percussion. The rock drilling machine 7 is fed in a direction F during the drilling by means of a feed device, which is not shown in FIG. 1.

[0085] The rock drilling rig 1 of FIG. 1 is intended for vertical surface drilling and may be equipped with the apparatus disclosed herein. However, the solution of FIG. 1 is an example of only one drilling application. The disclosed solution may also be utilized in other drilling solutions, such as in long hole drilling, face drilling, bench drilling etc.

[0086] FIG. 2 discloses an apparatus 11 for positioning sensing of a drilling tool. The apparatus 11 has one or more control units CU for analysing sensing data received from three or more magnetometers 12. The apparatus 11 further includes one or more magnetic sources 13 mounted to a rotatable drilling tool. The apparatus 11 may also be provided with depth sensing means 14 for determining advance distance of the magnetic source inside a drill hole.

[0087] FIG. 3 discloses a drilling tool 8, which may include several drilling components connected to each other. The drilling tool 8 may also have one or more drilling rods 15 or tubes and a drill bit 10. Between the rod 15 and the drill bit 10 may be an adapter piece 16. At least one of the components 15, 16, 10 is provided with at least one magnetic source 13. The magnetic source 13 is mounted so that axis of magnetic field 17 is transverse to drilling axis 9 of the drilling tool 8. It is possible to use several magnetic sources 13 in one component or provide several components with them.

[0088] FIG. 4 discloses a distal end part of a drilling tool 8. Between drill bit 10 and drill rod 15 is the adapter piece 16, which can be made of non-ferromagnetic material and can include a permanent magnet 13. The magnet 13 can then be located close to a face of the drill bit and a bottom 18 of a drill hole 2. As the distance between the magnet 13 and the bottom 18 is known the position of the drill hole bottom 18 may be thereby sensed by the disclosed solution.

[0089] FIG. 5 discloses that around magnetic source 13 may be a protective material 19, which may be of non-ferromagnetic material. The protective material 19 may dampen mechanical forces directed to magnetic source 13 and may also encapsulate it against harsh conditions occurring inside the drill hole. The protective material 19 may also participate in fastening of the magnetic source 13.

[0090] FIG. 6 discloses a control unit CU including a processor 20 for executing a position detection program 21 input to the control unit CU. The control unit CU further includes memory means 22 for storing programs and data, and data communication means 23 for communicating with servers and other control units, such as with a drilling control unit of a rock drilling rig or with a mine control system. The control unit has input means 24 for receiving position and orientation data, i.e. pose data on magnetometers 25.

[0091] When the position of the drilling tool is tracked, sensing data produced by the magnetometers 29 is input to control unit CU. Also, data on advance distance of the tracked magnetic source 30 may be input. The control unit analyses the input data and outcomes of the analysis and calculations executed by the processor 20 are transmitted through output means 31 to desired systems, servers and control units. The control unit CU may produce position data on the drilling tool 32, data on drill hole straightness or bending of the drilling tool 33, control commands for steering and controlling the drilling process 34 and updates 35 to drilling patterns, excavation plans and charging plans, for example.

[0092] FIG. 6 further discloses that rotation data 41 of the drilling tool and the included magnetic source may be sensed and input to the control unit CU. The rotation data 41 may be determined by means of separate sensing devices, which are located in connection with the drilling unit. The rotation data 41 of the drilling is known by the system, since rotation is one control parameter of the drilling process. However, the rotation data 41 may also be determined by analyzing sensing results received from the magnetometers.

[0093] FIG. 7 illustrates a principle of triangulation, which may be implemented in the disclosed position detection system. A drilling unit 5 provided with a feed beam 6 and a rock drilling machine 7 is positioned in a drilling position and drilling tool 8 penetrates inside rock material. Then a drill hole 2 is formed. Inside the drill hole 2 magnetic source 13is rotated together with the drilling tool 8, the accurate position of the magnetic source may not be known after a drilling period. However, positions of several magnetometers 12a-12c are known, whereby lengths of sides 45a, 45b and 45c of a formed basic triangle 46 can be calculated. Further, angles B, C and G from the magnetic source 13 towards the magnetometers 12a-12c are detected by analyzing phase differences between the received sensing data, as it is disclosed in this document. In FIG. 7 the phase angles B, C and G are only for illustrative purposes since the actual phase angles are examined as projections to the x-y plane defined by the magnetometers. Thus, a control unit CU is provided with sufficient and accurate data for calculating the position of the magnetic source 13 in x-y plane and in relation to the positions of the magnetometers 12a-12c.

[0094] FIG. 8 illustrates the disclosed measuring principle, wherein a drilling tool 8a, provided with magnetic source 13, is rotated at a first location 27a and rotation angles A can be sensed by means of magnetometers 12a-12c. Then the rotating magnetic field is sensed by the magnetometers 12a-12c and sensing data 28a-28c is generated at the first location 27a. Phase angles B1, C1 and G1 are determined by analyzing and comparing the sensing data. Thereby position data 32a of the first position 27a can be calculated. If so desired, the first position data 32a may be generated before the actual drilling is initiated, whereby the result may be compared to position data generated by a basic positioning system of the rock drilling rig.

[0095] During the actual drilling, sensing data 29a-29c is produced by the magnetometers 12a-12c. The drilling tool 8b may be subjected to transverse directed force components and may be forced to change its position from the intended position 27a in the examined plane and may move T transversally to a new position 27b. In the new position 27b alignment between the magnetic source 13 and the magnetometers 12a-12c is changed, whereby the phase angles B1, C1 and G2 are also changed. New phase angles B2, C2 and G2 can be determined by examining the new sensing data 29a-29c. Since positions 25a-25c of the magnetometers 12a-12c is known by the tracking system, position data 32a of the first position 27a and position data 32b of the new position 27b can be calculated.

[0096] FIGS. 9a and 9b further illustrate the position determination principle. The actual calculation is based on normal trigonometry, which is well known by one skilled in the art and is therefore not disclosed in detailed herein.

[0097] In FIGS. 8 and 12, lines 28a-28c and 29a-29b are used only to illustrate the sensing data. The actual sensing data has signals and has typically sine wave forms as it is disclosed in FIGS. 10 and 11. Thus, FIGS. 8 and 12 are simplified presentations for improving understanding of the disclosed solution.

[0098] FIG. 10 illustrates graphs of two sensing data 29a and 29b received by magnetometers 12a and 12b. In other words, one pair of graphs is presented for comparison. Magnitude or strength H of the sensed magnetic field in relation to time is illustrated. As can be noted, the sensing data 29a, 29b can be illustrated as sine waves. When examining the sine waves, for example, peak values 37a and 37b, it can be noted that there is a shift in the peak values 37a, 37b. In other words, the curves have a phase difference. The phase difference corresponds to a phase angle B2. The other two phase angles C2 and G2 can be illustrated and determined in a similar manner

[0099] FIG. 11 discloses readings or output of magnetometers 12b and 12c in function to a rotation angle A of the magnetic source. Sinus waves 29b and 29c have a different phase angle C2. The phase angle C2 can be determined despite the fact that amplitudes H1 and H2, i.e., strengths of the magnetic fields at the reference point and at the new changed location, are different. Thus, FIG. 11 illustrates that the position determination can be done without examining strength values of the magnetic fields. In other words, values of magnetic flux density E, i.e., sensed Tesla (T), have no significant importance to the determination of the phase angles.

[0100] FIG. 12 is another example of the disclosed measuring arrangement. As can be noted, the magnetometers 12a-12c may be located at different directions and distances relative to a drilling tool 8.

[0101] FIG. 13 discloses a measuring principle for determining bending of a drill hole 2. The drilling tool 8 is positioned at a start point of a drill hole. The positioning system of the rock drilling rig knows the accurate position of the drilling tool at the start point. Magnetometers 12a-12c are mounted on a rock surface 38 and they may be located at different distances L1 and L2 from the drilling tool 8. Positions of the magnetometers 12a-12c and the drilling tool 8 positioned to the starting point can be determined in a work site coordinate system 39, for example. When the drilling begins, position of the drilling tool 8 is determined by examining rotating magnetic field generated by magnetic source 13. Simultaneously, an advance distance of the drilling tool 8 is sensed by means of a sensor 14. When the position measurements are executed at several measuring points Mp1-Mp3 positions at different advance distances Ad1-Ad3 are detected. On the basis of the obtained data, straightness of the drill hole 2 can be examined in a control unit CU.

[0102] FIG. 14 discloses a solution, wherein magnetometers 12a-12c are connected to a drilling unit 5 by means of arms 40. The arms 40 may be movable and may comprise joints.

[0103] Although the present embodiment(s) has been described in relation to particular aspects thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred therefore, that the present embodiment(s) be limited not by the specific disclosure herein, but only by the appended claims.