Note: Descriptions are shown in the official language in which they were submitted.
~L049~
BACKGROUND OF T~IE INVENTION
This invention relates to a method and arrangement for automatically
positioning a working implement, such as a drill bit, to predetermined posi-
tions and/or predetermined directions in space, wherein said predetermined
positions and directions are defined by given values of respectively coor-
dinates and an angle or angles in a system of coordinates. - -
The invention may to advantage be used at rock drilling, which means
that the working implement is a drill bit. The ir.vention, however, is appli-
cable generally at positioning of different types of working implements, for
instance at controlling of industrial robots.
When applying the invention at rock drilling it is, due to the
irregularities of the rock surface intended to be worked, necessary to under-
take measures in order to safeguard that the drill bit does not get stuck
during movement from one predetermined position to another.
A further object of the invention is to provide an automatical move-
ment of the working implement to programmed positions according to a pattern,
such as a drilling pattern, such that the working implement is moved to a
predetermined position and may be adjusted to a predetermined direction in
shorter time than is obtainable in hitherto known constructions for auto-
matical movement o~ a working implement.
According to one aspect of the present invention there is provided
in a method of automatically positioning an elongated rock drilling apparatus
having a boom bracket, a drill boom swingably mounted on the bracket, a feed
bar swingably moun~ed on the drill boom and a rock drilling machine longitudi-
nally slidable to and fro along said feed bar, said rock drilling machine
driving a working implement, the method comprising entering set position
values corresponding to a plurality of predetermined positions in an imaginary
plane which is spaced from a rock surface to be worked in a computer unit,
s0nsing actual position values corresponding to the actual position of said
working implement, calculating the differences between said actual position
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values and said set position values, transforming said differences for pro-
viding position control signals, and swinging a drill boom relative to a
boom bracket, swinging a feed bar relative to said drill boom and displacing
said feed bar relative to said drill boom and boom bracket responsive to said
control signals to position said working implement at successive ones of said
predetermined positions.
According to another aspect of the present invention there is pro-
vided an arrangement for automatically positioning an elongated rock drilling
apparatus to a plurality of predetermined positions in space according to
a programmed drilling pattern, comprising a support, a drill boom swingably
mounted on said support, an elongated rock drilling apparatus carried by said
drill boom at the distal end thereof, and moving means for automatically
moving said rock drilling apparatus from a first predetermined position to
a second predetermined position in an imaginary plane which is spaced from a
rock durface to be worked upon completion of a drill hole corresponding to
said first predetermined position in said imaginary plane, said moving means
including: sensing means for sensing the actual position of said rock drill-
ing apparatus in a system of coordinates; a computer unit for registering
~et position values corresponding to said predetermined positions; register-
ing means for registering actual position values corresponding to said actual
position o~ said rock drilling apparatus; calculating means for calculating
differences between said actual position values and set position values;
transforming means coupled to said calculating means for transforming said
differences to position con~rol signals; and means controlled by said posi-
tion control si~nals for automatically moving said drill boom relative to
said support and said rock drilling apparatus relative to said drill boom
so as to move said rock drilling apparatus to said second predetermined
position.
BRIEF DESCRIPTION OF TtlE DRAWINGS
3Q In the accompanying drawings, which illustrate one embodiment of
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the present invention:
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Figure l is a side view of a drill boom and a feed bar having a rock
drilling machine movable to and fro therealongJ in which the invention is
applied;
Figure 2 is a top view of the drill boom according to Figure l;
and
Figures 3, 4 and 5 show in block diagram form the control means for
the hydraulic cylinders which determine the position of the drill boom and
feed bar shown in Figures 1 and 2,
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In Figures 1, 2, a drill boom 10 is carried pivotally on a cross
shaft 11 which is supported by a boom bracket 12. The pivotal angleo~
of the drill boom 10 about the cross shaft 11
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i8 Adjusted by means of hydra~lic elevating eylinder~ 139 14,
which are coupled pivotally between the boom bracket 12 and
the drill boom 10. The drill boom 10 can be ~WUIlg about a 3haft
16 which i9 perpendicular to the cross shaft 11 by means of a
hydraulic swing cylinder 15. The swing angle about the ~haft 16
i8 depicted o~,
The drill boom 10 carrie~ a boom head 17 at it~ di~tal
end, A cross shaft 18 i~ journalled in the boom head 17. The
cro~ shaft 18 carries a feed holder 19. A feed bar 20 i~
carried longitudinally ~lidably on the feed holder 19 by
means of guide~ fixed thereon, The feed bar 20 carries in
conventionsl manner a rock drilling machine 21 mechanically
fed to and ~ro therealong. The rock drilling machine 21 rotates
8 drill steel 22 and delivers impacts thereagain~t. The drill
~teel i8 guided by mean~ of a drill steel centralizer 23 o~
the fecd bar. The drill steel 22 carries 8 drill bit 24.
A feed displacing hydraulic cylinder 48 is attached on the
one hand to the feed holder 19, and on the other to the feed
bar 20. The feed bar 20 i~ adjusted longitudinally relative
1 20 to the drill boom 10 by cxtension ~r contraction of the
¦ h~draulic cylinder 48.
I I ~ A hydraulic tilt cylinder 25 i8 coupled pivotally
¦ ~ between the boom head 1`7and ~he feed holder 19 . By means of
the hydraulic cylinder 28 the feed holder 19 can be ~wung
I ~ 25 about a ~haft 27 which is perpendicular to the cro~s sha~t 18.
I The swing angle relative to the drill boom lO about the ~ha~
27 i8 depicted ~k~
In order to define the position and direction of the
drill bit 24 in an ~rbitrary point in Bpace it i~ necessary
~o know the coordinatss and angles of the trill bit 24 in 8
y~te~ o coordinates in space. In Figs. 1, 2, a sy~tem of
coordinatea i~ marked having its origin in the inter~ection
I point of the geometric axis of the shaft 16 and a plane which i~¦ perpend;cular to ~aid geome~ric axis and which traver~es the
, ~ 35 geo~etric axi~ of ths cros~ ~haft 1}. The Y-axi~ coincide~ ~rith
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ehe geometric ~xi~ of the shaft 16, the X axis i8 parallel with
~he cross shaf~ 11 and the Z-axis i~ perpendicular to the X-
~nd Y-axes.and extends in the longitudinal directi~n of the
drill boom 10, The distances along the X-axis and the Y-axis,
respectively, from a reference point on ehe shaf~ 16 at ~he
level of the cro3s shaft 11 to an imaginary line9 which
runs in the de~ired tunnel direction and intersect~ an ~m~g~n~ry plane 1
containing the predetermined position~, are dupicted respec-
tively X0 and Y0. Z0 depicta the distance between the
abovementioned reference point and pl&ne, The di~tance between
the geometric axe~ of the cros~ shaft 11 and the croos shaft
18 is depicted L5. L8 depicts the di~tance between the
geometric axi5 of the cross sh~ft 18 and the centre line of the
drill steel 22. The distance between the geometric axis of the
crogs ~haft 18 and the drill bit 24 i~ depicted L10. In Fig.
2, the di~tance between the geometric ~xes of the shat 16
and the croso shaft 11 io depicted L4, In the same figure,
L7 depice~ the distance between the centre line of the drill
boom 10, which line intersects the origin 0, snd the centre
line of the drill steel 22,
By the abovementioned definitions, the coordin~te~
o the drill bit 24 are as follows:
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X - XO ~ L4 ~in (~ x~ o~o) + L5 C09 ~y Bin (~ ~0)
~ L7 C08 (O~X ~ ~0) ~ L8 ~in (~ y ~ ~ g) sin (oL x ~ o~ o)
2S - L10 ~co~ ~ k C08 (1Y ~ 1B) oin (~x ~ o) - ~in
~ k cos (~ x ~ ~ o)~
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; Y -:~Y0 - L5 ~in ~ y 4 L8 cos (~ y ~ L10 c08 ~ k
n (o~y 4 ~ 0)
Z - ZO ~ L4 coa (o~ ~ 4 ~ o) ~ L5 cos~y co~ (~x ~o)
30 ~ L7 ~in (~CX ~ 0) - L8 ~in (O~ Y +0~ 8~ co~ (oC x ~o~ o)
~ LIO [CO80Ck CO~ Y 4~B) CO8 (~X ~0~0) ~ ain ~ k . `~
oin (o~x ~!o)J
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In the above terms, lo depicts an angle in the XZ-plane
~or the drill boom 10 with respect to a given reference angle,
The direction of the drill steel 22 and t:hus also the
direction of the drill bit 24 are defined as follow~:
K ~ oLo ~c~x tD~k
S ~y ~ ~s
The angle S depicts the direction of the drill steel 22
in a plane which traverses the centre line of the drill steel
22 and which i9 perpendicular to the shaft 18. K depicts the
direction of the drill steel 22 ;n a plane which also traveraes
the centre line of the drill ~teel 22 and i8 perpendicular
to said fir~tmen~ioned plane.
The angleso~ x, o~y, o~ k and oCs, re~pectively~ are
measured by connecting an angle sensing means, preferabl~ a
synchro, to respective swing shaft. The distance L10 i8
divided into ~wo componentsD a fixed one L9 whieh depicts
the distance when the feed displacing hydraulic cylinder 48
iB entirely contracted, and a variable one, con~tant .~z,
.. which depicts the exten~ion of the hydraulic cylinder 48.
~or measuring the component con~tant .~z 9 a rack member i8
i ~ mounted on the feed bar 20. The rack me~ber cooperates
with a gear wheel, which i~ moun~ed on the feed holder 19.
: Th~ turning of said gear wheel is transferred to a syncheo, where- by also the di~tance L10 i6 repre~ented as an angle.
In Figs. 3, 4 ~nd 5, a block diag~am illustrates
. how the po~itioning o~ the drill boom shown in Fig~. 1, 2
i8 carried out. Synchros 29, 30, 31, 32 and 33 are in known
manner provided with two unmovable windings, which are
perpendicular to one another and one turnable winding, The
~urning of the turnsble winding corresponds to the turning of
the shaft connected thereto. The unmovabIe windings are ener-
gized wi~h two sine-wave, 90 dephased, voltsges~ ~hich are
g~nerated in oscillators 34, 35 and transmitted via lead3
38, 39, 40 and power amplifiera 36, 37, When turnin~ ~he ~h~t
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of a ~ynchro, a sine~wave voltage having a con6tant
~ mplitude i~ generated over the turnable winding. This
~ine-wave voltage i~ de~hased with respect to the voltages
genera~ed in the o~cillators 34, 35 such that ~he pha~e
di~placement i8 proportional to the turning angle. The
oscilla~or~ 34, 35 are controlled in re~pect to frequency
and phase angle from a generntor 42 via a frequency divider
41.
The output signals from the synchros are transmieted to
`10 signal ~n~terter~ 43, 44, 45, 46, 47 in which the 6ignal~
are conver~ed to pulse duration signals having the ~ame
frequency a3 the ~inedwave ~ignal bue a pulse du~a~ion,
which is proportional to the respective an~le. A high fre-
quency iB 8uperpo~ed the pul6e duration ~lgnal~ ~o that a
high-fre~uent pulse trsin is ohtained having a number
of pul~es which i8 proportional to respective angle. These
pulse train~ appear in a frequency, which
corresponds to the sine-wave voltage originally transmitted
to the synchros. In a preferred embodimen~, all synchros
are fed with 400 Hz. The high frequency
transmitted to the converters has a frequency of about
400, 2 l~. 211 , i.e. about 5,1 MHz, which frequency
i8 doubled in the converter~ , Thi8 mean6 that 2-, 2
pul~es correspond to the turning angle of one revolution,
i,e, 212 ~ 4096 pul~es per radian. As regards the synchro
29 and the converter l~3, the high frequency is given a
value ~uch that ~z gets the same scale cons~ant as the
other lengths, L4, L5, L7, L8 and L9. Said frequency value i~
obtained by means of a binary-rate-multiplier : which
-~ 30 transforms a frequency from the genera~or 42 to M requenc~
~hich i~ suitable or the ~cale factor.
L10 is ob~ained in binary form on the output of M
counter 180 aa the 8um o~ L9 and the feed di~placement corres-
ponding to Lz , ~ignal~ of thi~ type, i,e. ~;gnals where
ehe number o~ pulse~ in a given time in~erval convey infor-
mation o ~ particular mea~ure~ are here called rate-~ignal~,
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The pulses can be ~paced equally or unequally within
the interval or a pArt thereof, The time interval must
be so long that the pul~es within two con~ecut;ve
interval3 will be refound in the same order and number
when the information i9 unchanged, If the pulses are
spAced equally within the whole in~erval they can be ~poken
of as a pulse frequency,
Separate leads from th~ conver~ers 43, 44, 45, 46,
47 are given signals indicating whether the angles are
positive or negative with respect to the reference direction,
Unit~ 86 and 87 form the angular sum~ required in
the ~ositioning equations, vi~ 0 and ~
~ 0 which i~ the angle of the boom bracket 12 r~lative to the
Z-axis in the XZ-plane, is measured ~hen the drill rig
lS has taken up it~ position and i~ then set on a thumb wheel
switch 181, The angular sum unit 87 compri~es a special
converter for converting the angle fro~ the thumb
~heel 9witch 181 from degrees to radians. The angular
sum f rom the two unit~ 86 and 87 is obtained as a pulse-rate-
signal having 4096 pulses per radian in analogou~ manner as the
- ~ignal from the convereerg 43, 44, 45, 46, h7 .
In the above terms of the coordinates, sinus and
cosinus of different angles are included, In order to get th~e
value~, the signals which represent the re~pective angle~
are transmitted to sin-cos- converters 82, 83, 8ll, 85.
The~è converters gi~e on its two output~ sinus and
cosinus respetively of the angles and the angular sumB
;~ ~ in binary form and with 12 bit accuracy. Sinus 90, thu~,
i9 represented by 212,
In order to get signal~ repre~enting the lengths
L4, L5, L7, L8, L10, and ~ig~als repre~enting sinus and cosinu~
o' ~ x' ~ y' ~ k~ ~ whic~ 9ignals can be
~,~ sdded and multiplied, ehere are bin~ry-rate-multiplièrs
55-81 in the control diagram,
35~ ~ The binary-rate-mu~tipliers are de~ignet ~uch that i~
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a rate signal is fed to the one input and a binary number to
the o~her input there is obtained another rate-signal on it~
output representing the product of ~he two input: mea~ures.
There is the following rela~ion:
r ~ in in ~ where
out 4096
~out ~ output rate-signal
rin ~ inpue r~te-sig~al
Bin ~ input binary number
4096 ~ 212 ~ maximum allowed input binary number
Con~equentlyj rOut is always les~ than rin.
The values of respectively 1.4, L5, L7, L8 snd L9 corre~-
pondin~ to the dimensions o~ the drill rig are represented as
binary numbers and are illustrated by 49, 50, 51, 52 and 53,
respectively. ;~
: : Unit~ 88, 89, 90, 91, 92 for handling signals have input3
lS for rate-signals with sign transmitted from the binary rate-
multiplicators ~the sign-leads are not shown), inputs for 8ig-
nals 123, 126, 135, 132, 129 represen~ing set values of the
measures X, Y, Z, ~ and S and inputs for administrating the func-
tion of the unit. The rate-~ignals represent the instant~neous . .-
20 value of the coordinates X, Y, Z and the angles R and S. The : :
ratesignals fed to one of these units are added with their
sign~ and are compared with a signal from a data proce~sing
computer 93, the latter signal being transormed to a rate-
signal snd represen~ing the se~ value~ The difference i8 tran~-
formed to a pulge duration signal having a sign signal for
; ~ X,::Y, Z, S, K, respecti~ely, ~hich pulse duratioll 2ignal
: is ~ed to leads 112-121.
In pulse-analogue- conver~ers 160, 161, 162~ 163,
164, these puls~ duration signal8 ar~ converted to an an~logue
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voltage The proportionality factor ~an be set by mean~ of a
binary ~ignal from leads 124, 127, 136, 133, 130, Stabilizing
nets being built-in op~imalize the dynamic characteristic~
^~ of the different channels.
The signalstre~ted in the above manner are then transmitted
to control magnet amplifiers 165, 166, 167, 168, 169, wherein
they are amplified and adapted to control magnets 170, 171
172, 173, 174.
The control magnet~ actuate mechanically control valves
175, 176, 177, 178, 179 , which give an oil flow being
proportional to the inpu~ signal to the control magnet ampli-
fiers. The speed of the hydraulic cylinders 15, 28, 48, 25,
14 9 thus, becomes proportional to the input signal to the con~rol
magnet amplifiers 165, 166, 167, 168, 169.
In the following, a positioning of a drill bit to a
predetermined position iB described. In the computer 93 are
stored coordinate~ of the position~ where the drill bit i~ to
be moved, and the deslred drilling direction in ~hese positions, The pro-
8rammed positions are in an imaginary plane, ~hich lie~ in
front of the rock ~urface. The set value of the X-coordinate of
~ posltlonb
the first~ 5 transmitted to the counter unit 88 from
the output 122 of the computor 93 via the lead 123. The
product of L4 and sin ( ~ ~ 1 o) ~ the re~pecti~e values
taken from the multiplier~ 56 and 57 respectively, i8 tran~-
mitted ~ia the lead 94 to the unit 88. Values of respectivelyL5, cos ~ y and sin ( oLx + d o) are got from ~he multipli-
cator~ 58, 59 and 60 respectively. The product of the~e value6
i8 transmiteed to the unit 88 via the lead 95. Values of L7
and co~ ~ o~ are got from the mul~iplicators 61 and
62.' The product of these values is transmitted to the
; unit 88 via the lead 96~ The values of L8, 3in ( ~ y ~ ~ s)
and ~n ~ ~ x ~ ~ o) are got from the multipliers 63,
64 and 65~ The product of these values i8 tran~mitted to the
unit 88 ~i~ the lead 97~ The valueJ of L10, cos ~ k~ cos ( ~ y ~ ~ s)
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and sin (d x ~ ~ o) are got from the multiplicators 66,
67, 68 and 69. The product of ~hese value~ is transmitted to
the unit 88 via the lead 98. The values of L10, sin ~ k and
co~ (o~x ~ o~o) are go~ from the multiplier~ 70,
71 and 72. The product of these values i9 transmitted to
the unit 88 via the lead 99. The values led into the unit
88 via the leads 94-99 nre ~ummed and the sum is the in~t~n--
taneous actual X-coordinate value of the drill bit.
Thi~ actual value is compared with the se~ value from the
; 10 lesd 123. Any differences between the actual ~alue and the
~et value cause correction ~ignals ~o be fed to pulse-
anslogue-con~ert~r 160 via leads 112, 113. The lead ~ :
112 indicates the duration of the correction signal
while the lead 113 indicates the sign of the correction
signal, i,e, in which di~ection the hydraulic cylinder
in question, in this case the swing cylinder 15, has to be
activated, The ~ignal from the pul~e-analogue-converter
160 is amplified in the amplifier 165, whereupon the signal ~:
actuateY the control magnet 170. The control ra8net adju~es
20 a Yalve 175. Due to in which direction the valv~ 175 i9 adjua~
tet hydraulic fluid i8 supplied to either of the ewo chamber~
of the hydraulic cylinder 15. The drill boom 10 i~ ~hen . .
swung~
Ths set value of the Y-coordinate of the fir~t poo~tion is
tran~mitted to the counter unit 92 from the output 128 of the
computer 93 via the lead 129. The product of the value~ of
respectively L5 and sin o~y ~ot from the multipliers 5
and 78 respectively i8 transmitted to the unit 92 via the
lead 109. The values of L8 and cos (o~y ~o~ 8) are got from
30 the multiplier~ 63 snd 79. The product of these values i~
. transmitted to the unit 92 via the lead 110. The values of
~; L10, co~ ~ and sin ( ~ y ~ ~ s) are go~ from respeceively
the multipliers 66 9 67 and ~Q. The product of these
, : val~es i8 transmitted to the unit 92 via the lesd 111. The
-.~ 35 value~ ed in~o the unit 92 via the leads 109-111 are
1~ ~ummed and the ~um represents the in~tantaneous ~ctual
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Y-coordinate value of the drill bi~. This actual value is ~ompared
with the set value fed vi.a the lead 129, Any differences
between the actual value and the se~ value cause a correc-
tion si~nal, which i5 fed to the pulse-analo~ue- conver~er
164 via leads 120 and 121 sespectively for respectively
the duration and the sign of the si~nal. The signal is
amplified in the amplifier 1~9 and is trans~itt:èd to the
magnet 174, The magnet adjusts the valve 179, which
controls the elevating cylinder 14. The drill boom 10 is
then elevated or lowered.
The ~e~ value of the Z-coordinat of the first position
i8 transmitted to the counter unit 90 from the output 134
of the computer 93 via the lead 135, The product of the
v~lues of L4 and C09 (oL X ~ 0~0) from the multiplier~q
56 nnd 81 regpectively is fed to ~he uni.t 90 via the
lead 102, The values of L5 , C09 o~y and C08 (d~x ~ CY~o)
sre got from the multiplicators 5a , 59 and 73. The pro-
duct of these values is transmitted to the unit 90 via th~
lead 103, The values o~ L7 nnd sin (cLx + ~ o) are got
from the multipli~rs 61 and 74. The product of ~hese
values is transmitted to the unit 90 via the lead 104. The vAlues
of L8, sin (oL y ~ ~ s) and cos (c~,x ~o~o) are got
from the multipliers 63, 64 and 75. The product of the~e
values i9 transmitted to the unit 90 via the lead 105. The
value~ of L10, co~ c~k , cos ~y ~ c~) and cos (O~x ~ ~ o)
are got from the multiplieræ 66, 67, 68 and 76. The product
of these values is transmitted to the unit 90 via the lèad 106.
The value~ of L10, sin ~ and sin ( ~ x ~ ~ o) are got
from the multipli~ers 70, 71 and 77. The product of these
value3 i~ transmitted to the unit 90 via the lead 107.
The values fed into the unit 90 via the lsads 102 - 107 are
summed and the ~um i9 the instsntaneous ac~ual value of the
Z-coordinate of the drill bit. This actual value is compared :.
with the ~et value fed via the lead 135. Any di~erences ~ :
. 35 between the actual value and the set vslue cause a correction ~.
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signal~ which is transmitted to the pulse-analogue-converter
162 via leads 116 and 117 respectively for respectively the
duration nnd the sign of the siRnal. The signal is amplified
in the amplifier 167 and is then fed to the magnet 172.
The magnet adjusts the valve 177, which controls the
feed displacing cylinder 48. The feed bar 20 i8 then di~-
placed.
The set value of the angle K of the first drill hole
i~ transmitted to the counter unit 89 from the outp~t 125
of the computer 93 via the lead 126. The sum of o~x , ando~o
is transmitted to the unit 93 via the lead 100. ~ k is fed
into the unit 93 via the lead 101, ~x and ~ and
:are summed in the unit 89 and the sum i8 the in3tantaneous
actual value of the angle K, This actual value is compared with
lS the set value transmitted via the lead 126. Any differenceH
between the actual value and the set value cause a correction
signal, which is transmitted to the pulse-analogue-conYerter
161 via lead~ 114 and 115 for the duration and sign of the
signal. The sign~l i9 amplified in the amplifier 166, where-
upon it is transmitted ~o the magnet 171. The magnet adjuststhe valve 176, which control~ the ~wing cylinder 28. The feed
bar 20 i9 then swung.
The set value of the angle S of the first drill hole ia
tr~n~mitted to the counter unit 91 from the output 131 of the
computer 93 via the lead 132. (c~y ~ ~ ~) is fed into
the unit 91 via the lead 108. This value is the instantaneous
actual ~alue of the angle S, Thi~ actual value i8 compared
~ith the set value transmitted via the lead 132. Any diference~
between the actu~l value and the set value cause a eorrection
~ 30 ~ignal, which is fed to the pulse~analo~ue-Cn~erter 163
i~ via the leads 118 and 119 for respectively the duration
and the sign of the ~ignal. The signal is amplified in the
amplifier 168, ~nd is then led to the magnet 173. The magnet
; adjus~ the ~al~e 178, which control~ ~he ~ilt cylinder
;35 :25, Th2 feed ba~ 20 i~ then tilted.
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Between each of the lead~ 112-121 respectively a summation unit
147 is connec~ed to a le~d respectively 137-146. A lead 148 is connected
between the summation unit 147 and the computer 93. The function of the
summation unit 147 i8 to give order to the computor 93 when value~ of
the next progra~med point have to be taken out. Before this order is
given~ the values of X, Y, Z, K and S of the previous points have to be
reached for a prescribed time, The condition for obtaining a sign&l from
the summation uni~ 147 through the lead 148 i~ that all lead~ 137-146
have been wi~hout signal for a prescribed time. When the summation unit
147 has ~ettled that th~ positioning is finished, the co~putor 93 give~
order to lock the positioning, open the supply of flushing fluid, make
a collaring and start the feed motor and rock drilling machine. The
drill depth i3 measured by counting the number of pulse3 from a toothed
wheel on the feed screw. A ~eparate logical system, not shown in the
block diagram, compares the actual drill depth wi~h a drill depth
programmed into the compu~or 93 via a lead 187. When similarity between
mea~ured and program~ed drill depth i8 achieved, the drilling is stopped
by rever0ing the feed motor.
Due to the irregularities of the rock surface, the Z-coordinates
of the predetermined positions are defined suoh that they are in an
imaginary plane, which i5 spaced from the rock surface, whereby safe-
guarding that the drill bit does not get stuck during movement from one
position to another. When the summation unit 147 has stated that the
positioning in the imaginary plane is finished, the computor 93 gives
orter to lock the drill boom and ~he feed bar against a turning about
their axe~, after a prescribed time delay displace the feed bar to
re~t against the rock, open the supply of ~lushing fluid, make a
collaring and start the feed motor and the rock drilling machine. The
displacemen~ of the feed bar aB well as the collaring can of course
alternatively be carried out manually.
The dcsired values of the coordinates X, Y, and Z and the angles
~ K, S ando~ are programmed starting from a given syste~ of coordinates.
; Due to the face of ~ountry etc, it i~ not alway~ possible to place the
j drill rig correctly in thia system. In occuring cases, the given
35 ~yBtEm of coordin~te~ has to be transformed to one which coincides with
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~oa~94~ :
the position in question of the drill rigO For this transformation
there are correction units 181-186. The correction factors for
respectively X, Y, Z, K andc~ are set by mean~ of the respective
unit or changer 181-186. The correction factor3 XO, Y , ZO, Ro, SO
and ~ o are defined by directly measuring the position and
inclination of the swing shaft 16 and the boom bracket 12 ~ith
re~pect to the geodetically determined line of the tunnel exte~3ion. :
,
. ~ .
14
.,
.
: :
.. - -
.
