U.S. patent application number 16/850197 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 | 20200332649 16/850197 |
Document ID | / |
Family ID | 1000004799937 |
Filed Date | 2020-10-22 |
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United States Patent
Application |
20200332649 |
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 the position of a
drilling tool during drilling is provided. The apparatus includes a
magnetic source mounted to a rotating drilling tool and at least
two magnetometers, which are located outside a drilled hole.
Sensing data of a 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
position data of the magnetometers and a reference position of the
drilling tool. The control unit compares the received sensing data
when the drilling tool is in the reference position and when being
moved to a new position. Phase angles are then detected from the
sensing data. The algorithm utilizes the phase angles and the known
positions of the magnetometers and the reference point when
calculating the changed 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: |
1000004799937 |
Appl. No.: |
16/850197 |
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 44/00 20060101 E21B044/00; E21B 47/01 20060101
E21B047/01 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 18, 2019 |
EP |
19170203.4 |
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 a direction of axis of the rotating magnetic field
deviates from the drilling axis; at least two magnetometers
configured to sense the rotating magnetic field generated by the
magnetic source; at least one control unit configured to receive
sensing data from the magnetometers and being configured to examine
the rotating magnetic field; and at least a first magnetometer and
a second magnetometer, which are both located external relative to
the drilling tool, wherein the control unit is provided with data
on position and orientation of the magnetometers, the control unit
being provided with reference data including first reference
sensing data of the first magnetometer, and second reference
sensing data of the second magnetometer, when the magnetic source
is located at a known reference position, and wherein the control
unit is configured to compare first sensing data of the first
magnetometer to the first reference sensing data for detecting a
first phase angle between them, and correspondingly, to compare
second sensing data of the second magnetometer to the second
reference sensing data for detecting a second phase angle, and the
control unit being configured to calculate a position change of the
magnetic source relative to the known reference position in
response to the detected phase angles and the known position of the
magnetometers.
2. 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 a corresponding rotation angle of the magnetic source
relative to the examined magnetometer, and the control unit being
configured to determine the phase angles between the reference
sensing data and any new sensing data by comparing the determined
rotation angles of the detected maximum strength values.
3. The apparatus as claimed in claim 1, wherein the magnetometers
are located on a rock surface surrounding the drill hole being
drilled.
4. The apparatus as claimed in claim 1, wherein the control unit is
provided with data on an advanced distance of the magnetic source
inside the drilled hole, the control unit being configured to
calculate three dimensional position data on the magnetic source in
response to the detected position and the received data on the
advance distance.
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, the control unit being
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 any claim 1, wherein the control
unit is provided with data on coordinates of the magnetometers and
the reference position in a work site coordinate systems, the
control unit being 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
configured to calculate position of a face surface of the drilling
tool in response to 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.
8. The apparatus as claimed in claim 1, wherein the control unit is
provided with a processor 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 reference
data and position data.
9. 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.
10. The apparatus as claimed in claim 1, wherein the magnetic
source is a permanent magnet.
11. The apparatus as claimed in claim 1, wherein the magnetic
source is mounted to a drill bit located at a distal end of the
drilling tool.
12. 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, wherein the rock drilling unit includes
a feed beam and a rock drilling machine supported movably on the
feed beam; and at least one apparatus according to claim 1 for
determining a position of the drilling tool connectable to the
drilling unit; and wherein the apparatus is in accordance with the
previous claims 1-11.
13. 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 the drilling and feeding the drilling tool axially forward
in an advance direction; detecting a change of 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 two magnetometers; generating a rotating magnetic
field by rotating the magnetic source together with the drilling
tool); sensing the rotating magnetic field by means of the
magnetometers and producing sensing data; generating reference data
by rotating the drilling tool at a known reference position and
detecting a first reference sensing data by means of a first
magnetometer and a second reference sensing data by means of a
second magnetometer; comparing first sensing data of the first
magnetometer to the first reference sensing data and detecting a
first phase angle therebetween and correspondingly, comparing
second sensing data of the second magnetometer to the second
reference sensing data and detecting a second phase angle; and
calculating a changed position of the magnetic source relative to
the reference position on the basis of the detected phase angles
and the position data of the magnetometers and the reference
position.
14. The method as claimed in claim 13, 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.
15. A computer program product having program code means configured
to execute the method of claim 13 when executed by 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. 19170203.4, 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, wherein
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 to rock material.
The drilling rig includes a drilling unit provided with a drilling
machine and a drilling tool is connected thereto. 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. This causes the finished drill hole to
deviate 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.
[0004] However, sensing properties of the drill hole during the
drilling is problematic. Conditions inside the drill hole during
the drilling are extremely harsh. Thereby no satisfying solution
for tracking position of the drilling tool during the drilling is
presently known.
SUMMARY
[0005] An object of the present disclosure is to provide a novel
and improved apparatus and method for tracking the drilling tool
during the drilling. 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 position of a
drilling tool is monitored during the drilling process.
[0007] 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.
[0008] The apparatus includes at least one magnetic source mounted
to a rotating drilling tool. Further, the apparatus has at a
minimum only two magnetometers and the magnetometers are located
outside the drill hole.
[0009] Sensing data of 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 pose of
the magnetometers and the position of a reference position of the
drilling tool. The control unit compares the received sensing data
when the drilling tool is in the reference position and when being
moved to a new position. Phase angles are then detected from the
sensing data. If no phase angles occur between the reference data
and the sensing data, then the drilling tool has not changed its
position. Typically, some position change occurs, and the algorithm
may utilize the detected phase angles, the known poses of the
magnetometers and the known position of the reference point when
calculating the changed position.
[0010] 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.
[0011] The disclosed system based on magnetism is suitable for all
kind of drilling circumstances, except situations where magnetic
material or iron ore disturbs the sensing of the rotating magnetic
field of the drilling tool.
[0012] 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 have different kinds of rock material and
different rock qualities, and still the sensing is not hampered
when the disclosed solution is used.
[0013] 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 for the positions of the magnetometers.
[0014] 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 enough 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.
[0015] Further, the disclosed solution requires only two
magnetometers at a minimum, whereby the number of the relatively
expensive magnetometers is limited and the apparatus may be
inexpensive.
[0016] According to an embodiment, the reference data is produced
prior to initiating the actual drilling. The drilling tool with the
magnetic source is then 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. The position of the drilling
tool may be used as the mentioned reference point, since its
position is accurately known by the rock drilling rig. A drilling
unit may be supported against a rock surface and the drilling tool
is rotated around its drilling axis. Rotating speed may be the same
used in the actual drilling. The rotating speed is sensed by
sensors of the rock drilling rig.
[0017] According to an embodiment, the reference data may be
produced at any time instance, even after the actual drilling has
already been initiated. However, also in this case, the position of
the drilling tool and the magnetic source needs to be detectable in
order to be used as the reference point.
[0018] According to an embodiment, the rotation rate of the
drilling tool is the same in the initial reference measurement and
in the actual measurement, or alternatively, the changed rotation
speed is taken into consideration in the determination of the phase
angles. In other words, the rotation speed is kept constant, or the
control unit compensates for the possible changed rotation speed so
that a comparison of the reference sensing data and the actual
sensing data is possible.
[0019] 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.
[0020] According to an embodiment, the control unit is configured
to calculate two-dimensional (2D) data on the position of the
drilling tool on the basis of the detected phase angles and the
input positions of the magnetometers and the reference position of
the magnetic source. 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.
[0021] 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.
[0022] 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.
[0023] According to an embodiment, the measurements and the
calculation of the position data are executed in real-time during
the drilling.
[0024] 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.
[0025] According to an embodiment, the frequency of the detected
alternating magnetic field is equal to the rotation speed of the
drilling tool.
[0026] According to an embodiment, the disclosed solution may be
implemented regardless of direction and purpose of the drill hole.
The disclosed measurement may then 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.
[0027] 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.
[0028] According to an embodiment, the apparatus may have three,
four or even more magnetometers, whereby two is the minimum number
of the magnetometers. When implementing greater number of
magnetometers, the accuracy of the measurements may be verified by
comparing several sensing results. This embodiment may also be
useful when operating at work sites where issues causing
disturbances to the magnetic fields occurs.
[0029] 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.
[0030] 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 is 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.
[0031] According to an embodiment, the control unit is configured
to detect phase difference between the reference sensing data and
an actual sensing data. Magnitude of the phase difference indicates
magnitude of change of position of the magnetic source from the
known reference position. In other words, magnitude of the detected
phase difference indicates magnitude of the phase angle. The phase
difference may be detected by examining the peak values, for
example.
[0032] 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.
[0033] 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.
Then, not only peak or other single values are examined, but
instead the analysis includes longer periods of time.
Alternatively, more than one wave lengths may be examined
[0034] The analysis takes 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. In summary,
there are alternative ways for analyzing the sensing data of the
magnetometers.
[0035] 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.
[0036] According to an embodiment, the magnetometers are located on
the surface level. Thus, 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.
[0037] According to an embodiment, the magnetometers are located on
a horizontal or substantially horizontal plane.
[0038] 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.
[0039] According to an embodiment, transverse distances of the
magnetometers from the drill hole are 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.
[0040] According to an embodiment, transverse distances of one or
more magnetometers from the drill hole may, in special cases, be
relatively small. Then one or more magnetometers may be located
nearby the drill hole, but in anyway, outside the drill hole.
[0041] According to an embodiment, the magnetometers are mounted to
the rock drilling rig. Then 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 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.
[0042] According to an embodiment, the disclosed solution utilizes
three directional magnetometers capable of sensing magnetic flux in
three components, x, y and z components. When position and
orientation of the magnetometers is known by the measuring system,
then selected sensed components may be examined when determining
the phase angles.
[0043] 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.
[0044] According to an embodiment, the data on advanced distance is
produced by means of a distance sensing device external to the
apparatus. It should be appreciated that there are several
alternative ways and principles for sensing the drilling depth.
[0045] 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.
[0046] According to an embodiment, the distance sensing device is
configured to determine distance between the drill bit and a drill
hole opening or mouth.
[0047] 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.
[0048] According to an embodiment, the determined data on bending
is implemented in determining quality of the rock drilling and
determining quality of the finished drill hole.
[0049] 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.
[0050] 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 and the reference position in a work site
coordinate system.
[0051] According to an embodiment, the above mentioned work site
coordinate system may be a mine coordinate system or a project
coordinate system.
[0052] 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.
[0053] 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.
[0054] 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.
[0055] 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 reference
and position data.
[0056] According to an embodiment, the position detection
algorithm, computer program product or software is configured to
implement triangulation and trigonometry in the calculation.
[0057] According to an embodiment, the control unit is configured
to execute the position determination without comparing strength of
the detected magnetic fields.
[0058] 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 when the magnetic source is at the reference point
and at a changed new position. 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 two phase angles indicating the position
change from the known reference point are detected, then the new
location can be calculated.
[0059] 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 to strength of the magnetic
field, then attenuation of the magnetic field in the rock material
has no influence to the disclosed positioning sensing
procedure.
[0060] 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.
[0061] According to an embodiment, the magnetic source is an
electromagnet or a coil.
[0062] According to an embodiment, the magnetic source is mounted
to a drill bit locating at a distal end of the drilling tool.
[0063] According to an embodiment, the magnetic source is mounted
to a drill rod or tube.
[0064] 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.
[0065] 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 as the magnetic field
penetrates well through the non-ferromagnetic material.
[0066] According to an embodiment, when the drilling tool or its
drilling component is made of ferromagnetic material, it may have 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.
[0067] 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 is then positioned at first to a reference location, such as
at a mouth opening of the drill hole, for producing the reference
data. Thereafter, the drilling tool is moved longitudinally to
desired one or more drill hole depths and a change of position of
the drilling tool and the magnetic source is calculated as
disclosed further herein.
[0068] According to an embodiment, the disclosed apparatus and
solution may be implemented in detection of the 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 the sensing data of
the actual drilling and the reference data. When the limit value is
exceeded then the drilling may be terminated, a warning signal may
be generated, or corrective measures may be initiated.
[0069] 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 longitudinal
direction inside a drill hole. In other words, 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.
[0070] 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. The above disclosed
embodiments may be combined in order to form suitable solutions
having those of the above features that are needed.
BRIEF DESCRIPTION OF THE FIGURES
[0071] FIG. 1 is a schematic side view of a rock drilling rig.
[0072] FIG. 2 is a schematic diagram presenting components of the
disclosed apparatus.
[0073] FIG. 3 is a schematic side view of a drilling tool and its
components provided with magnetic sources.
[0074] FIG. 4 is a schematic side view of a drilling tool at a
bottom of a drill hole.
[0075] FIG. 5 is a schematic side view of a magnetic source
surrounded by means of non-ferromagnetic protection material.
[0076] FIG. 6 is a schematic diagram showing a control unit
intended for executing position detection.
[0077] FIG. 7 is a schematic top view of a measuring arrangement
comprising two magnetometers and a magnetic source mounted to a
rotating drilling tool.
[0078] FIG. 8 is a schematic graph of magnetic field measurements
taken by a magnetometer at a reference position and at a changed
position of the magnetic source.
[0079] FIG. 9 is a schematic side view of a measuring arrangement
for detecting drill hole straightness.
[0080] FIG. 10 is a schematic side view showing an alternative
mounting arrangement for magnetometers.
[0081] FIG. 11 is a schematic representative graph of magnetic
field measurements and determination of a phase angle.
[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 have 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 the 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 as
disclosed herein. However, the solution of FIG. 1 is 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 includes one or more control
units CU for analysing sensing data received from two 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 an 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 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 an adapter piece 16 made
of non-ferromagnetic material and having a permanent magnet 13. The
magnet 13 is then close to a face of the drill bit and a bottom 18
of a drill hole 2. The distance between the magnet 13 and the
bottom 18 is known and the position of the drill hole bottom 18 may
thereby be sensed by the disclosed solution.
[0089] FIG. 5 discloses that around a 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 having 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.
[0091] The control unit has input means 24 for receiving position
and orientation data on magnetometers 25. Reference data 26
including data on the reference position 27 of the magnetic source
and reference sensing data 28 of the magnetometers is also input to
the control unit before executing actual position measures. 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
the advance distance of the tracked magnetic source 30 may be
input.
[0092] The control unit analyses the input data and outcomes of the
analyses 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.
[0093] 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.
[0094] FIG. 7 illustrates the disclosed measuring principle,
wherein the drilling tool 8, provided with a magnetic source 13, is
rotated and rotation angles A can be sensed by a first magnetometer
12a and a second magnetometer 12b. Reference data needed in the
calculation can be produced by rotating the drilling tool 8 at a
known reference position 27. Then the rotating magnetic field is
sensed by the magnetometers 12a and 12b and first reference sensing
data 28a and second reference sensing data 28b are generated. The
reference data may be generated before the actual drilling is
initiated.
[0095] During normal drilling actual sensing data 29a, 29b is
produced by the magnetometers 12a, 12b. If the drilling tool 8
changes its position from the known reference point 27 in the
examined plane and moves in direction T to a new position 36, then
a first phase angle B exists between the first reference sensing
data 28a and the actual first sensing data 29a, and correspondingly
a second phase angle C exists between the second reference sensing
data 28b and the actual second sensing data 29b. This is due to
changed alignment between the first magnetometer 12a and the
magnetic source 13, and correspondingly between the second
magnetometer 12b and the magnetic source 13.
[0096] Further, positions 25a, 25b of the magnetometers 12a, 12b
are known by the tracking system, whereby position data of the new
position 36 can be calculated. The actual calculation is based on
normal trigonometry, which is well known by one skilled in the art
and is therefore not described in detailed herein.
[0097] In FIG. 7 lines 28a-28c and 29a-29b are used only to
illustrate the sensing data. The actual sensing data comprises
signals and has a typical sine wave form as it is disclosed in
FIGS. 8 and 11. Thus, FIG. 7 is a simplified presentation for
improving understanding the disclosed solution.
[0098] FIG. 8 discloses graphs of the first reference sensing data
28a and the first actual sensing data 29a. The magnitude or
strength H of the sensed magnetic field in relation to the rotation
angle A of the drilling tool is illustrated. As can be noted, the
reference data 28a and the sensing data 29a 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 the first phase
angle B. The phase angle C can be illustrated and determined in a
similar manner
[0099] FIG. 9 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 and this point can be used as a
reference point. The positioning system of the rock drilling rig
knows the accurate position of the drilling tool at the start
point. Magnetometers 12a and 12b 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, 12b and the
drilling tool 8 positioned at the reference point can be determined
in a work site coordinate system 39, for example. When the drilling
begins, the position of the drilling tool 8 is determined by
examining rotating magnetic field generated by a magnetic source
13. Simultaneously, the advance distance of the drilling tool 8 is
sensed by means of 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.
[0100] FIG. 10 discloses a solution, wherein magnetometers 12a, 12b
are connected to a drilling unit 5 by means of arms 40. The arms 40
may be movable and may include joints.
[0101] FIG. 11 discloses readings or output of a magnetometer 12b
in function to a rotation angle A of the magnetic source. A
reference sinus wave 28b and actual sensing sinus wave 29b have a
different phase angle C. The phase angle C 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.
[0102] Although the present embodiments have 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 embodiments
be limited not by the specific disclosure herein, but only by the
appended claims
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