U.S. patent application number 16/850559 was filed with the patent office on 2020-10-22 for apparatus and method for determining position of drilling tool during drilling.
The applicant listed for this patent is SANDVIK MINING AND CONSTRUCTION OY. Invention is credited to Henna JUSSILA, Sirpa LAUNIS, Timo LEINO, Juha PIISPANEN.
Application Number | 20200332650 16/850559 |
Document ID | / |
Family ID | 1000004799628 |
Filed Date | 2020-10-22 |
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United States Patent
Application |
20200332650 |
Kind Code |
A1 |
PIISPANEN; Juha ; et
al. |
October 22, 2020 |
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.
Inventors: |
PIISPANEN; Juha; (Tampere,
FI) ; LEINO; Timo; (Tampere, FI) ; LAUNIS;
Sirpa; (Tampere, FI) ; JUSSILA; Henna;
(Tampere, FI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SANDVIK MINING AND CONSTRUCTION OY |
Tampere |
|
FI |
|
|
Family ID: |
1000004799628 |
Appl. No.: |
16/850559 |
Filed: |
April 16, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 44/00 20130101;
E21B 47/01 20130101; E21B 47/092 20200501 |
International
Class: |
E21B 47/092 20060101
E21B047/092; E21B 47/01 20060101 E21B047/01; E21B 44/00 20060101
E21B044/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 18, 2019 |
EP |
19170185.3 |
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
RELATED APPLICATION DATA
[0001] This application claims priority under 35 U.S.C. .sctn. 119
to EP Patent Application No. 19170185.3, filed on Apr. 18, 2019,
which the entirety thereof is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to an apparatus configured to
determine location of a drilling tool during rock drilling. The
apparatus utilizes magnetic field measurements. The disclosure
further relates to a rock drilling rig provided with the disclosed
apparatus and to a method and computer program product for
determining location of a drilling tool during rock drilling.
BACKGROUND
[0003] In mines and at other work sites, different type of rock
drilling rigs are used for drilling drill holes in rock material.
The drilling rig includes a drilling unit provided with a drilling
machine and a drilling tool connected to it. During the drilling
the drilling tool is subjected to different forces, whereby the
drilling tool may move side wards and away from the planned
drilling line. Because of this, the finished drill hole deviates
from the designed drill hole and may cause problems to procedures
following the drilling. Therefore, different devices and methods
are disclosed for examining properties of the drilled holes.
However, sensing properties of the drill hole during the drilling
is problematic. Conditions inside the drill hole during the
drilling are extremely harsh. No satisfactory solution for tracking
position of the drilling tool during the drilling is presently
known.
SUMMARY
[0004] An object of the present disclosure is to provide a novel
and improved apparatus and method for tracking the drilling tool
during the drilling.
[0005] A further object is to provide a rock drilling rig equipped
with such apparatus and a computer program for implementing the
disclosed solution.
[0006] An idea of the disclosed solution is that the position of a
drilling tool is monitored during the drilling process. The
solution discloses a magnetic tracking system for sensing sideward
or lateral position movements of the drilling tool. In the
disclosed solution position sensing of the drilling tool is based
on magnetism.
[0007] The apparatus has at least one magnetic source mounted to a
rotating drilling tool. Further, the apparatus includes at a
minimum three magnetometers and the magnetometers are located
outside the drill hole.
[0008] Sensing data of the rotating magnetic field is transmitted
from the magnetometers to a control unit provided with a position
calculation algorithm. The control unit is also provided with basic
data for the calculation, wherein the basic data includes the pose
of the three or more magnetometers.
[0009] The control unit receives sensing data from the
magnetometers and determines phase difference between the received
data. The determined phase differences correspond to phase angles
between the magnetometers and the magnetic source.
[0010] The control unit includes a calculation program or
algorithm, the execution of which calculates position of the
drilling tool on the basis of the detected phase angles and the
known poses of the magnetometers.
[0011] An advantage of the disclosed solution is that there is no
need to use downhole instruments to determine the heading of a
borehole. A further advantage is that the disclosed solution
provides a measurement-while-drilling (MWD) solution, i.e., the
measurements are done during the drilling of the drill holes. The
disclosed measurement process and arrangement does not hamper the
drilling in any way. The measuring may also be initiated at any
time during the drilling, or the measurement process may be
executed continuously during the drilling.
[0012] The disclosed system based on magnetism is suitable for all
kinds of drilling circumstances, except situations where magnetic
material or iron ore disturbs the sensing of the rotating magnetic
field of the drilling tool.
[0013] A further advantage is that the magnetic field can be sensed
from a very long distance. The rock material being drilled may be
nonhomogeneous and may comprise different kind of rock material and
different rock qualities, and still the sensing is not hampered
when the disclosed solution is used.
[0014] Since the magnetometers are located outside the drill hole
being examined, positioning of the magnetometers is easy and quick
to make, and further, there are plenty of optional locations to be
selected as the positions of the magnetometers.
[0015] The solution is also inexpensive, since no extensive
re-design needs to be done for the drilling equipment. Providing
the drilling tool with one or more magnetic sources is sufficient
and requires only minor modifications or extras to the existing
drilling tools. It may even be possible to retrofit the magnets to
the existing drilling components.
[0016] According to an embodiment, the disclosed position detection
system may be calibrated or verified prior to initiating the actual
drilling. Then the drilling tool with the magnetic source is
positioned at a desired drill hole position and is aligned
according to the desired drill hole direction. The drill hole
position and direction may be pre-determined in a drilling pattern
or excavation plan. A drilling unit may be supported against a rock
surface and the drilling tool is rotated around its drilling axis.
Thereafter, the position of the drilling tool is calculated in
accordance with the disclosed solution and the outcome may be
compared to the position accurately known by the rock drilling
rig.
[0017] According to an embodiment, the control unit may be
configured to monitor changes in the phase angles and when
pre-determined limits or rules are exceeded, the control unit may
then calculate accurate position data.
[0018] According to an embodiment, the magnetic flux sensed by the
magnetometers is examined in function to the rotation angle of the
drilling tool. Thus, the examination is not executed in function to
time.
[0019] According to an embodiment, the control unit is configured
to calculate two-dimensional (2D) data on position of the drilling
tool on the basis of the detected phase angles and the input
positions of the several magnetometers. In other words, the control
unit calculates position changes in transverse directions relative
to the drilling axis. The control unit may examine the situation in
a two-dimensional plane.
[0020] According to an embodiment, the apparatus is without any
electrical sensing devices mounted to the drilling tool. Thereby,
no electrical sensing devices are inserted together with the
drilling tool inside the drill hole during the drilling.
[0021] According to an embodiment, the apparatus may be implemented
in rotary drilling, as well as, in percussion drilling. Further,
the apparatus is suitable to be used in connection with top hammer
and down-the-hole drilling solutions. The disclosed solution may
also be implemented in surface and underground drilling.
[0022] According to an embodiment, the measurements and the
calculation of the position data are executed in real-time during
the drilling.
[0023] According to an embodiment, the control unit is configured
to take into consideration only rotating magnetic fields, the
rotating speed of which corresponds to the rotational speed of the
drilling tool. Thereby, possible other magnetic fields may be
filtered, separated and possibly ignored when seeking the rotating
magnetic field of the drilling tool.
[0024] According to an embodiment, the frequency of the detected
alternating magnetic field is equal to the rotation speed of the
drilling tool.
[0025] According to an embodiment, the disclosed solution may be
implemented regardless of direction and purpose of the drill hole.
Thus, the disclosed measurement may be executed for vertical
drilling when downward or upward directed drill holes are drilled.
Further, the measurement is also suitable for substantially
horizontal drilling, such as to face drilling in tunneling.
[0026] According to an embodiment, positions of the magnetometers
may be freely selected as long as their position and orientation is
determined and input to the control system before initiating the
measurements. Positions of the magnetometers may be determined by
means of external position measuring systems, for example. The
magnetometers may possibly be kept in the same known position when
several neighboring drill holes are drilled. This way, the
magnetometers need not to be repositioned after each drill hole is
finished. In other words, the known pose setting of the
magnetometers is utilized for several separate drill holes.
[0027] According to an embodiment, the apparatus may have three,
four or even more magnetometers. Three is the minimum number of the
magnetometers, since otherwise there is too little initial position
and angle data to solve the position calculation trigonometrically.
When implementing a greater number of magnetometers, accuracy of
the measurements may be verified by comparing even more several
sensing results. This embodiment may also be useful when operating
at work sites where issues causing disturbances to the magnetic
fields occurs.
[0028] According to an embodiment, the control unit is provided
with a computer program product or algorithm for executing the
needed calculations. The calculation program or software implements
triangulation and trigonometry in the calculation.
[0029] According to an embodiment, the received sensing data is
examined by determining maximum strength values of the received
magnetic field data and corresponding rotation angle of the
magnetic source relative to the examined magnetometer at that peak
value being detected. Further, the phase angle between the
reference sensing data and any new sensing data is determined by
comparing the rotation angles of the detected maximum strength
values. In other words, this embodiment utilizes sensed peak
values.
[0030] According to an embodiment, the control unit may or may not
detect the above mentioned phase angle and phase difference by
examining the peak values of the sensed magnetic field.
Alternatively, minimum strength values may be used for the
detection.
[0031] According to an embodiment, a further alternative for
determining the phase angles and phase differences is to analyze a
wider sample of the sensing data or to continuously monitor the
sensing data for detecting the phase difference and phase angle. In
this way, not only peak or other single values are examined, but
instead the analysis includes longer periods of time.
Alternatively, more than one wave length may be examined. The
analysis may take into account one or more wave lengths sensed
before momentum of the calculation. The calculation of the phase
angles may be based on signal processing methods. Alternatively, or
in addition to, mathematical analysis, such as vector algebra and
Fourier transformation, may be implemented for determining the
phase differences and phase angles. Accordingly, there are several
alternative ways for analyzing the sensing data of the
magnetometers.
[0032] According to an embodiment, the magnetometers are located on
a rock surface surrounding the drill hole being drilled. Then
mounting of the magnetometers on the surface is easy and quick.
[0033] According to an embodiment, the magnetometers are located at
surface level. Then data transfer between the magnetometers and the
control unit is easy to arrange. Further, when the magnetometers
are surface mounted, they are not subjected to harsh underground
circumstances. Thereby, it is possible to use standard commercially
available magnetometers for the measuring.
[0034] According to an embodiment, the magnetometers are located on
a horizontal or substantially horizontal plane.
[0035] According to an embodiment, the known positions of
magnetometers and the reference position of the magnetic source
define a two-dimensional plane where the position change of the
magnetic source is examined The positions may be defined in X-Y
coordinates.
[0036] According to an embodiment, transverse distances of the
magnetometers from the drill hole is selected in relation to the
designed depth of the finished drill hole. The distances are
usually several meters, and may be up to 10-20 meters, for
example.
[0037] According to an embodiment, transverse distances of one or
more magnetometers from the drill hole may in special cases be
relatively small. If so, one or more magnetometers may be located
nearby the drill hole, but in anyway, outside the drill hole.
[0038] According to an embodiment, the magnetometers are mounted to
the rock drilling rig. Thus, the magnetometers may be mounted on a
carrier, to a drilling boom or to a drilling unit, for example.
Further, the magnetometers may be mounted to arms so that they may
be located at greater lateral distance from the drilling tool. Due
to the arms, the magnetometers may be positioned at desired
locations around the drilling tool. The above-mentioned arms may be
movable so that the position and distance relative to the drilling
tool may be changed. The arms may also have a retracted transport
or storage position and an extended sensing or operational
position.
[0039] According to an embodiment, the disclosed solution utilizes
three directional magnetometers capable of sensing magnetic flux in
three components, i.e., x, y and z components. When the position
and orientation of the magnetometers is known by the measuring
system, then selected sensed components may be examined when
determining the phase angles.
[0040] According to an embodiment, in addition to the detected
two-dimensional change of position of the magnetic source, a third
dimension is also included. Thus, drilling depth is measured and is
included in the examination. This way three-dimensional position
data can be produced. The drilling depth may also be called as an
advance distance.
[0041] According to an embodiment, the data on advanced distance is
produced by means of a distance sensing device external to the
apparatus. There are several alternative ways and principles for
sensing the drilling depth.
[0042] According to an embodiment, the distance sensing device is
mounted to a drilling unit of the rock drilling rig. The drilling
unit manipulates the drilling components during the drilling and
the distance sensing unit locating in the drilling unit may monitor
feeding of the drilling components.
[0043] According to an embodiment, the distance sensing device is
configured to determine distance between the drill bit and a drill
hole opening or mouth.
[0044] According to an embodiment, the solution aims to detect
bending of the drilling tool during the drilling and the caused
deviations in straightness of the drilled hole. In order to detect
the bending, several measurements at different drill hole depths
needs to be executed. Then several measuring points locating at
different advance distances of the magnetic source inside the
drilled hole are used. The number and depth of the measuring points
may be selected case by case. At each measuring point sensing data
received from the magnetometers is analyzed and position data is
calculated. The control unit compares the calculated position data
and determines the bending on the basis of the detected differences
in the calculated position data.
[0045] According to an embodiment, the determined data on bending
is implemented in determining the quality of the rock drilling and
determining the quality of the finished drill hole.
[0046] According to an embodiment, the determined data on bending
is implemented during the drilling for initiating and controlling
corrective measures. The corrective measures may include
directional drilling, wherein the drilling is actively steered for
compensating the detected bending of the drilling tool and the
drilled hole. A still possible implementation is to steer the
drilling tool purposely so that it becomes bent, and to thereby
produce drill holes with desired non-linear advance profile or side
profile.
[0047] According to an embodiment, the control unit is configured
to produce coordinate data on the changed position of the magnetic
source. Then the control unit is provided with data on coordinates
of the magnetometers in a work site coordinate system.
[0048] According to an embodiment, the above mentioned work site
coordinate system may be a mine coordinate system or a project
coordinate system.
[0049] According to an embodiment, the above mentioned position
data with the coordinates may be linked via the work site
coordinate system to a drilling plan, charging plan or reinforcing
plan.
[0050] According to an embodiment, the control unit is configured
to calculate position of a face surface of the drilling tool in
response to the input position data of the magnetic source relative
to the face surface, whereby the position of the drilling tool is
examined as the position of the face surface.
[0051] According to an embodiment, the position of the above
mentioned face of the drilling tool equals the position of a bottom
of the drill hole during the drilling phase. The position of the
drill hole bottom is important especially when charging the drilled
hole with explosives.
[0052] According to an embodiment, the control unit is provided
with one or more processors configured to execute a position
detection algorithm, the 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.
[0053] According to an embodiment, the position detection
algorithm, computer program product or software is configured to
implement triangulation and trigonometry in the calculation.
[0054] According to an embodiment, the control unit is configured
to execute the position determination without comparing the
strength of the detected magnetic fields.
[0055] According to an embodiment, the strength of the detected
magnetic field has no importance to the position detection since
the detection is based on determining phase angles of the sensed
magnetic fields. The rotating magnetic source generates the
alternating magnetic field, which is sensed by the magnetometers
locating at different positions. The rotating magnetic field is
aligned with the magnetometers at different phases. When at least
three phase angles are detected, then the new location can be
calculated.
[0056] According to an embodiment, the magnetometers may be located
at different distances from the drill hole, and further, the rock
material surrounding the drill hole may have different properties.
Therefore, the strength of the magnetic field detected by the
separate magnetometers is different. When the position detection is
based on the phase angle, and not on the strength of the magnetic
field, then attenuation of the magnetic field in the rock material
has no influence to the disclosed positioning sensing
procedure.
[0057] According to an embodiment, the magnetic source is a
permanent magnet. The permanent magnet is inexpensive and its
mounting to the drilling tool is relatively simple.
[0058] According to an embodiment, the magnetic source is an
electromagnet or a coil.
[0059] According to an embodiment, the magnetic source is mounted
to a drill bit locating at a distal end of the drilling tool.
[0060] According to an embodiment, the magnetic source is mounted
to a drill rod or tube.
[0061] According to an embodiment, the magnetic source is mounted
to an adapter piece which is located between the drill bit and the
drill rod or tube. The adapter piece may be a component that is
designed especially for receiving the one or more magnetic
sources.
[0062] According to an embodiment, the magnetic source is covered
or surrounded with non-ferromagnetic material. The material may be
resilient material and may thereby serve as protective material
layer. The surrounding material may dampen forces directed to the
magnetic source during the operation and may thereby lengthen life
time of the magnetic source. Especially in percussion drilling, the
dampening feature may be found useful. The magnetic field
penetrates well through the non-ferromagnetic material.
[0063] According to an embodiment, when the drilling tool or its
drilling component is made of ferromagnetic material, it may
include a recess on its radial outer surface for receiving the
magnetic source together with surrounding non-ferromagnetic filling
material. When a special adapter element is applied between the
drill bit and a drill rod or tube, then the adapter may be made of
stainless steel, or another non-ferromagnetic steel material.
[0064] According to an embodiment, the disclosed apparatus and
solution may be implemented for examining straightness of the
already drilled drill holes. The drilling tool with the magnetic
source can then be positioned at a mouth opening of the drill hole.
Thereafter, the drilling tool is moved longitudinally to the
desired one or more drill hole depths and change of position of the
drilling tool and the magnetic source is calculated as disclosed
further herein.
[0065] According to an embodiment, the disclosed apparatus and
solution may be implemented in the detection of drill hole
straightness without calculating absolute positions of the magnetic
source. Instead of the calculated position coordinates, the control
unit may be provided with a limit value for the maximum deviation
of the phase angle or phase difference between two measurements.
When the limit value is exceeded then the drilling may be
terminated, a warning signal may be generated, or corrective
measures may be initiated.
[0066] According to an embodiment, the disclosed measuring
principle may be implemented in connection with a special measuring
means. The magnetic source is then mounted to a measuring
instrument, probe, component or element, which may be rotated
around its longitudinal axis and may be moved in a longitudinal
direction inside a drill hole. In other words, in this embodiment,
does not include any drilling tool. The disclosed embodiment may be
a special measuring device intended for measuring straightness of
the already drilled drill holes.
[0067] The foregoing summary, as well as the following detailed
description of the embodiments, will be better understood when read
in conjunction with the appended drawings. It should be understood
that the embodiments depicted are not limited to the precise
arrangements and instrumentalities shown.
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.
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