WO2007100287A1

WO2007100287A1 - Method and device for automatic calibration of a rock drilling joint and rock drilling rig comprising such a device

Info

Publication number: WO2007100287A1
Application number: PCT/SE2007/000179
Authority: WO
Inventors: Johan Larsson; Håkan LUNDVALL
Original assignee: Atlas Copco Rock Drills Ab
Priority date: 2006-02-28
Filing date: 2007-02-27
Publication date: 2007-09-07
Also published as: EP1989394A1; SE0600438L; EP1989394A4; SE529667C2

Abstract

The present invention relates to a method and a device for calibration of joint means in a rock-drilling rig comprising at least one joint means, wherein a joint motion speed for the said joint means is controllable by means of control means, and wherein the influence of the said control means upon the motional speed of the said joint means is designed to be controlled by a control parameter. The method comprises the steps of setting a value for a control parameter, determining whether the deviation between the joint motion speed obtained by means of the control parameter value and a reference joint motion speed falls below a certain threshold value, increasing/reducing the value for the said control parameter if the said deviation exceeds the said threshold value, and automatically repeating the above steps until the said deviation falls below the said threshold value. The invention also relates to a device and rock-drilling rig.

Description

Method and Devise for Automatick Calibration of a Rock Drilling Joint and Rock Drilling Rig Comprising such a Device

Field of the invention

The present invention relates to a method and device for automatic calibration of joint means in a rock- drilling rig.

Prior Art

In rock-drilling in general and in tunnel drilling in particular, a rock-drilling rig is often used in which one or more drilling machines are supported by respective movable arms, so called booms. The booms are usually articulately fastened to a carrier, such as a vehicle, by one or more joints. Furthermore, the respective drilling machine is articulately fastened by one or more additional joints to that end of the respective boom which is facing away from the carrier. The drilling machine is usually fastened not directly to the boom, but via a feeder along which the drilling machine can be transported during drilling.

Usually a construction is used in which the boom is fastened to the carrier in such a way that the boom is movable about two joints, and in which manoeuvring about these two joints, for example, can be realized by a tripod construction having two hydraulic cylinders disposed substantially parallel with the boom, which are fastened to the carrier below, and laterally displaced in each respective direction, relative to the fastening point of the boom, to allow raising/lowering and lateral rotation of the boom. In order to realize the motion of the feeder relative to the other end of the boom, a corresponding construction is used, yet in which the front cylinders are oppositely disposed, i.e. fastened to the top side of the boom. In this way, a constant load direction upon the constituent components is obtained, which has the advantage that any play within the joints has no or only slight impact upon the boom. In front of the front joint, furthermore, there is disposed a rotation joint, with which the feeder can be rotated about the longitudinal axis of the boom. Moreover, a feeder tilt joint is usually present, with which the feeder can be angled upwards/downwards. Another example of a boom construction is constituted by a boom in which the front tripod and the said rotation joint are exchanged for two rotation joints such as rotators. The advantage with this construction is that the rotation joints reduce the weight at the outer end of the boom, which in turn means that a both longer and stiffer boom can be used. Moreover, the mobility of the feeder is increased.

Common to the above boom types is that the hydraulic system which is used to manoeuvre the boom usually comprises standard components, constituted, for example, by proportional valves, which are used to control/adjust the speed of movement for the abovementioned boom-manoeuvring joints. A drawback with the use of standard components is that the characteristics of these components vary between different units. These variations, in turn, give rise to variations in the extent to which a joint moves, given a certain position of the control stick. This is undesirable, since it leads to different joints moving at different speeds, resulting in an unwanted pattern of motion for the feeder. For example, differences in the proportional valves result in a so-called parallel displacement not occurring parallelly at all. In drilling, furthermore, automatic displacement of the boom/drilling machine is often used, in which it is even more important that the joints behave precisely as intended in order that a reliable autopositioning can be obtained.

With a view to overcoming these problems, a calibration of these valves is therefore normally carried out to compensate for the said component variations . This calibration is very time-consuming, however, and must be carried out each time a component (valve or joint) is exchanged. Moreover, the calibration result is dependent on the experience of the operator who has conducted the calibration (by operator in calibration terms is here meant service personnel, since it is unusual for a drill operator to possess this knowledge) . There is therefore a need for an improved rock-drilling device.

Summary of the invention

One object of the present invention is to provide a method and a device for the calibration of joint means in a rock-drilling rig, which method and device solve the above problems.

This and other objects are achieved according to the present invention by a method as defined in claim 1 and a device as defined in claim 13.

According to the present invention, a method for the calibration of joint means in a rock-drilling rig is provided. The method comprises the steps of: setting a value for a control parameter, determining whether the deviation between the joint motion speed obtained by means of the control parameter value and a reference joint motion speed falls below a certain threshold value, increasing/reducing the value for the control parameter if the said deviation exceeds the said threshold value, and automatically repeating the abovementioned until the said deviation falls below the said threshold value, the obtained control parameter value being stored as the calibration value for the said reference joint motion speed.

This has the advantage that, since the calibration takes place automatically, the calibration is independent of who performs the calibration, i.e. a result is obtained in which a rock-drilling rig always behaves in the desired manner. The invention also has the advantage that the calibration can be carried out significantly faster than with previously known methods .

The calibration can be carried out for all motional directions of the said joint means. This has the advantage that a calibration can be realized which ensures that a good result can be obtained in respect of, for example, parallel displacement or automatic positioning .

The rock-drilling rig can comprise a plurality of joint means, in which case the method further comprises the step of carrying out the said calibration for the said plurality of joint means. This has the advantage that, for example, all the joint means of a boom can be calibrated successively. In certain cases, it may also be possible to calibrate a plurality of joint means in parallel. This can call for plenty of space around the rock-drilling rig, however, since it may be required that large boom motions are possible. It may also be that the rock-drilling rig comprises a plurality of booms, for example two, three or four, in which case joint means on different booms can be calibrated in parallel, which further speeds up the calibration process .

The method can further comprise the step of carrying out the said calibration for a plurality of reference joint motion speeds. The abovementioned calibration can be carried out to determine that control parameter value which results in the joint means precisely starting to move, which can be constituted by a definitive determination, i.e. that the absolute position detection means, which are normally disposed by the respective joint, detect that the joint is moving or that, for example, 1, 2 or 3% of the maximum motional speed of the joint means (as defined below) has been reached. The calibration can also be used to determine the control parameter value which results in the joint moving at its maximum speed, which can be the maximum speed imposed by physical limitations, or the speed which is the maximum at which it is desirable for the joint means to move. The said joint means can also, however, be calibrated for intermediate joint motion speeds, as the characteristic curve of the joint means is not normally linear. For example, calibration can be carried out for 10, 20, 50 and 80% of the abovementioned maximum speed.

The said control means can be designed to be constituted by a proportional valve, the said control parameter being designed to be constituted by a control current for the said valve. This has the advantage that conventional standard components can be used. Furthermore, the said joint means can be constituted, for example, by a hydraulic cylinder, or a rotation joint means such as a rotator.

Since it is often cramped where rock-drilling is carried out, the method can further comprise the step that a user, by means of control means, specifies a direction in which the said drilling machine or boom is allowed to move during the said calibration. This has the advantage that in a cramped mine location, for example, the user, by, for example, holding a control stick in a certain position, for example forwards, can specify for the control system that, during calibration, the boom/drilling machine can only move in the specified direction. The specified direction can be constituted by a two-dimensional direction.

The invention also relates to a device and a rock- drilling rig.

Brief description of the drawings

Fig. 1 shows an exemplary boom for a rock-drilling rig. Fig. 2 shows a flow chart for the calibration of a starting current for a joint means according to the present invention.

Fig. 3 shows an exemplary characteristic curve for an exemplary joint means.

Fig. 4 shows a flow chart relating to rough calibration of the control current for the maximum speed of a joint means and any intermediate speeds according to the present invention.

Fig. 5 shows a flow chart relating to fine calibration of control currents for the maximum speed of a joint means and possible intermediate speeds according to the present invention.

Fig. 6 shows another exemplary boom in which the present invention is applicable.

Detailed description of preferred embodiments

In Fig. 1, a rock-drilling rig 1 is shown in which the present invention can advantageously be used. The rock- drilling rig 1 comprises a boom 2, one end 2a of which is fastened to a carrier 10 (indicated schematically) , which can be constituted, for example, by a vehicle, and at the other end 2b of which there is disposed a feeder 3 supporting a drilling machine 4. The drilling machine 4 is displaceable along the feeder 3. The rock- drilling rig 1 can further be remote-controlled by an operator via a control device which is connected to the rock-drilling rig 1 by means of a cable (not shown) and in which control means in the form of, for example, one or more control sticks (such as joysticks or track balls) can be used to control the direction and position of the drilling machine 4. The control device can also be wirelessly connected to the rock-drilling rig. Alternatively, the rock-drilling rig can be controlled by an operator located in a cab (not shown) disposed on the carrier/vehicle 10. The shown rock- drilling rig is depicted as only comprising one drilling boom, but can comprise two, three, four or more drilling booms, each boom supporting a respective drilling machine 4.

As previously mentioned, the boom(s) 2 is/are usually articulatedly fastened to the vehicle/carrier 10 by one or more joint means. In Fig. 1, these joint means are constituted by a tripod construction, in which two hydraulic cylinders 6, 7 are fastened to the vehicle 10 somewhat below and laterally displaced relative to the point of attachment of the boom, so that the three points of attachment form the shape of a triangle in which the points of attachment of the hydraulic cylinders 6, 7 define the base of the triangle. The other ends of the hydraulic cylinders 6, 7 are fastened to the bottom side of the boom 2. Control of the cylinders 6, 7 allows the boom 2 to be raised/lowered and guided in the lateral direction. Usually, the said control device is provided with a separate control stick for this purpose, in which the boom 2 is raised/lowered by moving the control stick backwards/forwards. In the same way, the boom is guided to the right/left by moving the control stick to the right/left.

Furthermore, the drilling machine 4 is articulately fastened to that end 2b of the boom 2 which is facing away from the vehicle by a correspondingly working device having two cylinders 8, 9, which are fastened to the top side of the boom and then, in corresponding manner to the cylinders 6, 7, in the shape of a tripod with the apex, i.e. the attachment of the boom, downwards. With the aid of the cylinders 8, 9, therefore, the feeder 3, and hence the drilling machine 4, can be angled forwards/backwards and rotated about an axis running transversely to the longitudinal axis of the drilling boom. In other words, the feeder can constantly be kept parallel, at the same time as the boom is raised/lowered and/or turned to the right/left. The feeder can also be turned in the lateral direction with the aid of the cylinders 8, 9. Furthermore, the feeder with drilling machine can be rotated about the said tripod attachment by means of a rotation joint 11. Moreover, a feeder tilt joint 12 is present, which is used to angle the feeder about its fastening point.

According to the above, it is therefore a plurality of joints which influence the motional direction for the drilling machine 4. In the case of certain feeder/drilling machine displacements, it is important that a parallel displacement of the feeder can be executed, i.e. that the boom can be turned with maintained feeder direction, so that drilling of a new hole, parallel with previous holes, can be rapidly carried out. This parallel displacement in turn requires that the joints move at the same speed. For example, in a boom according to Fig. 1, it is desirable that the cylinders 6 and 9, and 7 and 8, respectively, move at the same speed to produce a satisfactory- parallel displacement. Overall, it is important that the correct position and correct angular direction relative to the rock are obtainable for the feeder/drilling machine so as to be able to produce a desired hole, and this too means that it is important for the joint means to move at equal speed so that a displacement specified with the control stick also results in a corresponding actual displacement. Furthermore, in automatic positioning of boom and drilling machine, the calibration value of the starting current has very great influence. In automatic positioning, it is required that the joint means can be very accurately adjusted, since the permitted adjustment error is usually in the order of magnitude of a few hundredths of a degree. Furthermore, if the starting current is too high, the boom cannot be manoeuvred slowly enough to be able to be stopped in the correct position, if the starting current is too low, the automatic positioning instead takes too long a time .

As mentioned above, the hydraulic system which is used to manoeuvre the boom usually comprises standard components, in which proportional valves are used to control the hydraulic flow to the joint means, and hence the motional speed for these. As also mentioned above, these components have the drawback that their characteristics vary between different models. These variations in turn give rise to variations in the extent to which a joint moves in response to a certain position of the control stick. Since this can result, for example, in the cylinders 6 and 9, and 7 and 8, not moving at the same speed, a calibration of the joint means is therefore carried out before the rock-drilling rig is put into operation, with a view to ensuring that the motional speeds of the cylinders (the joint means) are mutually consistent. In this example, the joint means (cylinders) are controlled by proportional valves, and these valves are therefore calibrated.

The calibration signifies that a starting and a maximum current are determined for each respective valve, i.e. each joint means such as a hydraulic cylinder or hydraulic motor. The starting current signifies the current which must be supplied to the proportional valve to enable the valve to genereate a sufficiently large flow so that the cylinder/motor starts to move. The maximum current corresponds to the current which must be supplied to the proportional valve to enable the maximum speed of the joint means to be reached. Furthermore, it is not sufficient to determine the starting current and maximum current for one direction of the joint means, but rather the starting current and the maximum current must be determined for both directions of the joint means. This means that, for a boom according to Fig. 1 having six joints (boom swing, boom lift, feeder lift, feeder swing, feeder tilt, feeder rotation), 2x2x6=24 values must be set. The boom is usually extensible, however, which gives a further joint, in addition to which the feeder is displaceable in the longitudinal direction, which gives yet another joint, in which case the number of values which have to be set instead becomes 2x2x8=32. Furthermore, a rock- drilling rig often comprises more than one boom, for example, three, in which case, with the above-described boom type, 96 values have to be set (calibrated) . This calibration is currently carried out manually, which leads to variations in the calibration result depending on who conducts the calibration. This means that whilst a rig which has been calibrated by an experienced operator will exhibit a better performance in precision positioning (which in tunnel drilling, for example, is especially important at the periphery of the tunnel, where the outermost holes, the so-called contour holes, are directed obliquely outwards to prevent the tunnel from becoming increasingly narrow) than that of a rig calibrated by a less experienced operator, which is undesirable. Apart from the fact that the calibration result varies, this calibration takes a long time to perform. Moreover, the calibration must be carried out each time a component (valve or joint means) is exchanged.

The present invention overcomes these problems with a calibration method in which, instead of an operator, the control system of the rock-drilling rig carries out the calibration.

According to one embodiment of the invention, the calibration of a valve (joint) is carried out in three phases. A first phase will be explained with reference to the flow chart in Fig. 2.

In the first phase, the starting current of the valve is determined. This phase is initiated in step 201 by applying a predefined control value to the valve. In one example, this value is constituted by 0 mA, but can be constituted, for example, by 5, 10, 250 or 500 inA. Following the applying of the starting current, the process waits a certain time, step 202, for example 3 s, before the speed of the joint means is measured, step 203. The joint means are usually provided with absolute position sensors, an absolute position for each boom joint being able to be obtained at each moment. The arrangement of these absolute position sensors is known per se and will not therefore be more closely described here. In determining the extent to which the joint means moves per se, a starting position, i.e. the particular position for the boom joint, for example, can be read in step 201, this position being able to be compared by virtue of a new reading in step 204. If the position has been changed, it can be determined that the joint is moving. The determination of the extent to which the joint means moves does not, however, need to be constituted by the definitive affirmation that the joint means is moving, but rather this determination can alternatively also be constituted by the fact that the joint means is moving at a certain reference speed which, in calibration terms, is deemed to constitute the speed at which the joint means starts to move. That such can be the case has its basis in the fact that this "start to move" speed can be based on the speed which an experienced operator feels precisely constitutes the speed at which the joint means starts to move and which has been shown in practice to give a good result. Experience from experienced operators can therefore be used in determining the various limit values to be used in the calibration process.

Furthermore, if it is determined in step 204, based on the measurement in step 203, that the joint means is stationary, in step 205 is increased by X mA, for example 64 mA, whereupon the process returns to step 202 so as to wait a certain time before a new measurement is conducted. The process thereby continues to step up the control current until in step 204 it is determined that the joint means is not stationary.

Once it has been determined that the joint means is moving, the process continues to step 206, in which it is determined whether the joint means is moving at faster than t% of the maximum speed of the joint means (preassumed or predetermined) , or whether the incrementation of the starting current which is used in each step is greater than 1 mA (for example 64 mA according to the above) . The value of t can be set, for example, at 3%. If it is determined that the joint means is not moving at more than 3% of the maximum speed, in step 207 the particular current value is stored as the starting current for the valve/joint means in question. If, on the other hand, the joint means is moving at more than 3% of the maximum speed, the process continues to step 208, in which the current value is reduced by X mA, whereafter X is halved, i.e. to 32 mA in the above example. The process then returns to step 202, whereafter, if it is determined that the joint means is not moving, the current value is now increased by 32 mA, whereafter the process continues according to the above with smaller and smaller X until it is determined that the joint means is not moving at more than 3% of the maximum speed. As will be appreciated by a person skilled in the art, the value 3% represents only one example and can be constituted by an arbitrary percentage of the maximum speed. Alternatively, a set speed (reference joint motion speed) , for example based on individual experiences of operators, can be used. The obtained current value is then stored as the calibration value for the speed at which the joint is deemed to start moving.

Instead of terminating the process once the control current value constitutes a percentage of the maximum speed, the process can instead be steered towards a specific minimum joint motion speed, whereby, by successively reducing of X according to the above producing a more and more exact current value will be produced until its speed lies within a fixed margin of error (i.e. the deviation between actual speed and the reference joint motion speed falls below a threshold value) from the set value.

As will be apparent, the same flow chart can be used to determine the control current for the maximum joint motion speed of the joint means, i.e. the maximum current, in which the adjustment proceeds until the measured speed lies within a set margin of error, for example +/-3% of the set (or actual) maximum speed.

Furthermore, the above calibration is carried out for both motional directions of the joint means, since joint means normally have different characteristic curves in different motional directions.

The advantage of carrying out a calibration according to the present invention is that the result is independent of who performs it, i.e. even a relatively inexperienced person can perform the calibration with perfectly satisfactory result. Moreover, the result of the calibration can further be guaranteed by having the limit value determined by the person (s) most capable of calibrating a rock-drilling rig. Furthermore, the automated method is significantly faster than manual calibration, resulting in shorter downtime for the rock-drilling rig and hence a more economical drilling.

The present invention also has a further advantage. Since the above-described automatic calibration proceeds significantly faster than has previously been possible, more calibration points can be introduced. In Fig. 3, an example is shown of a typical valve characteristic curve representing joint motion speed as a function of the control current to the valve. As can be seen in the figure, the characteristic curve 302 is not linear, and the linear approximation 301 which was previously used with starting and maximum value constitutes an approximation which differs relatively greatly from the reality. By introducing a plurality of intermediate calibration points, a significantly better representation of the valve characteristic curve can be obtained, and hence a smoother motion for the feeder. For each respective joint, apart from starting current and maximum current, for example, current values for 10%, 20%, 50% and 80% of the maximum speed of the joint can be set. The setting of these parameter values can be carried out according to the above.

With a view to speeding up the process, prior to fine calibration of the resultant current values in the above points, a rough estimate can first be made. A process for performing this is shown in Fig. 4. In step 401, the control current calculated according to the above is applied. In step 402, the control current is then increased by Z mA, for example 30 mA. After this, the achieved speed, together with its associated current value, is measured and stored in step 403. In step 404, it is determined whether the maximum speed has been reached. If the maximum speed of the joint has not been reached, the process reverts to step 402, in which the current value is again increased by Z mA, whereupon the process continues until the maximum speed has been reached. By proceeding in this way, it is possible in step 405 to extrapolate current values for the above-specified calibration points, whereupon fine calibration can start with these rough-set current values as a good approximation. The fine calibration can be carried out according to Fig. 2, but the method shown in Fig. 2 is unnecessarily time-consuming. Instead, a fine calibration method according to Fig. 5 can advantageously be used.

In step 501, an operator can choose which joint motion speed that is to be calibrated, for example maximum speed or an intermediate speed. Instead of an operator making this choice, it can also be fully automated, in which case the control system of the rock-drilling rig instead makes this choice. In step 502, that value for the chosen calibration point which has been obtained according to the rough calibration process shown in Fig. 2 is applied. In steps 503 and 504, the control value is adjusted until the measured speed is consistent with the desired speed, this adjustment being able to be carried out, for example, by means of a conventional PI (proportional integral) adjustment. PI adjustment is well described in the literature and will not therefore be more closely described here. No waiting step as described in the calibration of the starting current is required, but rather the PI adjustment can be carried out continuously. This has the advantage that the calibration process can be carried out more quickly. When it is determined in step 504 that measured speed is consistent with desired speed, in step 505 the particular control current is stored as the calibration value for this speed. In step 506, a check is made on whether all calibration points have been gone though, in which case the process is terminated in step 507. Otherwise, the process continues to step 508 for advancement of the calibration point, whereafter the process returns to step 502 and calibrates the advanced calibration point.

The present invention also has a further characteristic. The place in which calibration of a rock-drilling rig is carried out is often limited for space, for example the calibration may need to be done in a mine location with restrictions in the freedom of movement of the boom both in the vertical direction and in the lateral direction. In this situation, the calibration can be carried out by the control system of the rock-drilling rig, but under the influence of an operator who, by means of a control stick, for example, specifies the direction in which the boom is allowed to move during the calibration. For the boom shown in Fig. 1, this means, for example, that in the calibration of the hydraulic cylinder 6, the hydraulic cylinder 7 must simultaneously be manoeuvred (by the control system based on the direction specification of the operator) in order to ensure that no boom swing/boom lift in an unwanted direction is obtained.

In order to further speed up the calibration process, it may in certain cases also be possible to calibrate a plurality of joint means in parallel. This can call for plenty of space around the rock-drilling rig, however, since large boom motions may be required. For example, in respect of boom lift motion of the boom shown in Fig. 1, calibration of both the valves for the cylinders by which the front (or rear) tripod is manoeuvred can be carried out simultaneously. It may also be that the rock-drilling rig comprises a plurality of booms, for example two, three or four, in which case calibration of joint means on different joints can be carried out in parallel, which further quickens the calibration process.

The calibration mechanism according to the invention has been described above in connection with a specific boom type. As will be appreciated by the person skilled in the art, the calibration mechanism can also, however, be used in all other boom types in which joints need to be calibrated. An example of such a boom 50 is shown in Fig. 6. As regards the attachment of the boom 50 to the rock-drilling rig, this works precisely the same as for the boom in Fig. 1, with like-working tripod with cylinders 54, 55, the motion of the boom up/down and in the lateral direction being able to be controlled wholly according to the above. As far as the front tripod is concerned, however, this, together with the rotation joint 11, has been exchanged for two rotation joints 51 (feeder rotation), 52 (feeder swing) , which together with the feeder tilt 53 can be used to provide the same or better facilities for guiding the feeder in different directions and therefore replace the hydraulic cylinders 8, 9. The rotation joints 51, 52 are placed essentially at 90 degrees relative to each other, where the rotation joint 51 is fastened to the boom and therefore allows rotation about the longitudinal axis of the boom. Rotation by means of the rotation joint therefore entails that the feeder is rotated about the longitudinal axis of the boom. The rotation joint 52 is disposed at right angles to the rotation joint 51 and therefore allows rotation of the feeder about a, in relation to the boom, transverse axis. The present invention can therefore also be used for various types of joints, such as rotation joints with rotation motors as in Fig. 6. These rotation joints, too, are conventionally provided with means for absolute position detection, which will not be more closely described here.

The present invention has been described above in connection with specific types of joint means controlled by proportional valves, which in turn are controlled by means of a control current. The invention is not limited to this type of joint means control, however, but is equally applicable to all types of joint means and control means for joint means, regardless of whether these control means are controlled by means of current, voltage or some other parameter .

Claims

I. Method for the calibration of joint means (β-9,

II, 12; 51-55) in a rock-drilling rig (1), wherein the said rock-drilling rig comprises at least one boom (2; 50) having a first end and a second end, wherein the said boom (2; 50) is designed to support a drilling machine (4), wherein the said first end is fastened to a carrier and wherein the said drilling machine (4) can be fastened to the said second end by at least one joint means (8-9, 11, 12; 51-53), wherein a joint motion speed for the said joint means (6-9, 11, 12; 51- 55) is controllable by means of control means, and wherein the influence of the said control means upon the motional speed of the said joint means (6-9, 11, 12; 51-55) is controlled by a control parameter, characterized in that the method further comprises the steps of:

- a) setting a value for the said control parameter,

- b) determining whether the deviation between the joint motion speed obtained by means of the control parameter value and a reference joint motion speed exceeds a threshold value for the said deviation,

- c) adjusting the value for the said control parameter if the said deviation exceeds the said threshold value,

- d) automatically repeating steps b-c until the said deviation falls below the said threshold value, and

- e) storing the obtained control parameter value as a calibration value for the said reference joint motion speed.

2. Method according to Claim 1, wherein the said adjustment of the value for the said control parameter if the said deviation exceeds the said threshold value comprises increasing/reducing the said control parameter value.

3. Method according to Claim 1, wherein the said adjustment comprises an increase of the said control parameter value if an increase of the control parameter value reduces the said deviation, and wherein the said adjustment comprises a reduction of the said control parameter if a reduction of the said control parameter value reduces the said deviation.

4. Method according to any one of Claims 1-3, wherein it further comprises the step of carrying out steps a-d for all motional directions of the said joint means (6- 9, 11, 12; 51-55) .

5. Method according to any one of Claims 1-4, wherein the said rock-drilling rig (1) comprises a plurality of joint means (6-9, 11, 12; 51-55), the method further comprising the step of carrying out the said steps for the said plurality of joint means (6-9, 11, 12; 51-55).

6. Method according to any one of Claims 1-5, wherein the method further comprises the step of carrying out the said steps for a plurality of reference joint motion speeds.

7. Method according to any one of the preceding claims, characterized in that the said reference joint motion speed (s) is/are constituted by one or more from the group: maximum speed, predetermined percentage of maximum speed, predetermined minimum speed.

8. Method according to Claim 7, wherein the said minimum speed is constituted by a predetermined percentage of the maximum speed of the said joint means

(6-9, 11, 12; 51-55), or the speed which is the least at which a motion can be detected, or a predetermined speed.

9. Method according to any one of the preceding claims, wherein the said control means is constituted by a proportional valve and wherein the said control parameter is constituted by a control current for the said valve .

10. Method according to any one of the preceding claims, wherein the said joint means (6-9, 11, 12; 51- 55) are constituted by one or more from the group: hydraulic cylinder, rotation joint means such as a rotator .

11. Method according to any one of the preceding claims, wherein the method further comprises the step that a user, by means of control means, specifies a direction in which the said drilling machine (4) is allowed to move during the said calibration.

12. Method according to any one of the preceding claims, wherein the said boom (2; 50) additionally is fastened to the carrier by at least one joint means (6, 7; 54, 55), and wherein the method further comprises the step that a user, by means of control means, specifies a direction in which the said boom (2; 50) is allowed to move during the said calibration.

13. Device for the calibration of joint means in a rock-drilling rig (1), wherein the said rock-drilling rig (1) comprises at least one boom (2; 50) having a first end and a second end, wherein the said boom (2; 50) is designed to support a drilling machine (4), wherein the said first end is designed to be fastened to a carrier and wherein the said drilling machine (4) is designed to be fastened to the said second end by at least one joint means (8-9, 11, 12; 51-53), wherein a joint motion speed for the said joint means (6-9, 11, 12; 51-55) is controllable by means of control means, and wherein the influence of the said control means upon the motional speed of the said joint means (6-9, 11, 12; 51-55) is designed to be controlled by a control parameter, characterized in that the device further comprises:

- a) means for setting a value for a control parameter, - b) means for determining whether the deviation between the joint motion speed obtained by means of the control parameter value and a reference joint motion speed exceeds a threshold value for the said deviation, and

- c) means for adjusting the value for the said control parameter if the said deviation exceeds the said threshold value.

14. Device according to Claim 13, wherein the said means for adjusting the value for the said control parameter if the said deviation exceeds the said threshold value comprise means for increasing/reducing the said control parameter value.

15. Device according to Claim 13, wherein the said means for adjusting the value for the said control parameter comprise means for increasing the said control parameter value if an increase of the control parameter value reduces the said deviation, and means for reducing the said control parameter value if a reduction of the said control parameter value reduces the said deviation.

16. Device according to any one of Claims 13-15, wherein it further comprises means for calibrating all motional directions of the said joint means (6-9, 11, 12; 51-55) .

17. Device according to any one of Claims 13-16, wherein the said rock-drilling rig (1) comprises a plurality of joint means (6-9, 11, 12; 51-55), the device further comprising means for carrying out the said calibration for the said plurality of joint means (6-9, 11, 12; 51-55) .

18. Device according to any one of Claims 13-17, wherein the device further comprises means for carrying out the said calibration for a plurality of reference joint motion speeds.

19. Device according to any one of Claims 13-18, characterized in that the said reference joint motion speed (s) is/are constituted by one or more from the group: maximum speed, predetermined percentage of maximum speed, predetermined minimum speed.

20. Device according to Claim 19, wherein the said minimum speed is constituted by a predetermined percentage of the maximum speed of the said joint means

21. Device according to any one of Claims 13-20, wherein the said control means is designed to be constituted by a proportional valve and wherein the said control parameter is designed to be constituted by a control current for the said valve.

22. Device according to any one of Claims 13-21, wherein the said joint means (6-9, 11, 12; 51-55) are constituted by one or more from the group: hydraulic cylinder, rotation joint means such as a rotator.

23. Device according to any one of Claims 13-22, wherein the device further comprises means for allowing a user, by means of control means, to specify a direction in which the said drilling machine (4) is allowed to move during the said calibration.

24. Device according to any one of Claims 13-23, wherein the said boom (2; 50) additionally is designed to be fastened to the carrier by at least one joint means (6, 7; 54-55), and wherein the device further comprises means for allowing a user, by means of control means, to specify a direction in which the said boom (2; 50) is allowed to move during the said calibration .

25. Device according to any one of Claims 13-24, wherein the said direction specified with the control means is constituted by a two-dimensional direction.

26. Device according to any one of Claims 13-25, wherein the said drilling machine (4) is designed to be fastened to the said boom (2; 50) by a feeder.

27. Rock-drilling rig (1), characterized in that it comprises a device according to any one of Claims 13- 26.