WO2008033077A1

WO2008033077A1 - Method and device for calibration of an electronic brake system

Info

Publication number: WO2008033077A1
Application number: PCT/SE2007/000797
Authority: WO
Inventors: Fredrik Grahn; Tobias Furuholm
Original assignee: Atlas Copco Rock Drills Ab
Priority date: 2006-09-15
Filing date: 2007-09-12
Publication date: 2008-03-20
Also published as: EP2061682A4; SE0601911L; CL2007002680A1; SE530305C2; EP2061682A1

Abstract

The present invention relates to a method for calibration of an electronic braking system for a machine and/or a vehicle. The method comprises the steps of generating a control signal for generating a high braking force by means of the said braking system, of generating a positive motor torque with a gear selected for generating a propulsive force acting on the said machine and/or vehicle, of reducing the said applied braking force by means of the said control signal until the said braking force essentially corresponds to the said propulsive force, of storing a parameter value that represents the said control signal value that represents the braking force that essentially corresponds to the said propulsive force, and of determining a control range for the said control signal for the said braking system on the basis of the said measured parameter value.

Description

METHOD AND DEVICE FOR CALIBRATION OF AN ELECTRONIC BRAKE SYSTEM

TECHNICAL FIELD

The present invention relates to a method and a device for the calibration of an electronic braking system for a vehicle according to the preamble to Claims 1 and 15 respectively. The invention also relates to a computer program according to the preamble to Claim 29, a computer program product according to the preamble to Claim 30, a rock drilling rig according to the preamble to Claim 31, a vehicle according to the preamble to Claim 32, and a loader or truck according to the preamble to

Claim 33.

BACKGROUND ART

Vehicles/machines of various kinds are used within many spheres of activity for, among other things, transportation of goods and bulk products, and diverse special applications. These vehicles/machines are often driven in cramped/dangerous environments, for example in association with tunnelling and mining, where, for example, loaders and trucks are used. Very stringent requirements are laid down for the use of machines in such environments, including requirements for the machines' braking systems, as it must be ensured that these will function in all situations. A hydraulic service brake is therefore often used in these machines, with a particular hydraulic pressure being required in order for the wheels to be able to rotate freely. When the pressure drops, the machine is retarded, for example by spring-loaded plates that act against brake disks, with a non-pressurized system providing a full braking force. This has the advantage that if, for example, a stone damages a hydraulic pipe, the brakes are locked immediately in order to prevent accidents.

The braking force that is applied can be controlled mechanically via, for example, a brake control device, such as a brake pedal or a brake control in the form of, for example, a knob or a lever, that directly controls the hydraulic pressure. Today, however, it is usual to have electronic braking systems, with the braking force being controlled instead by an electronic control signal, and with the size of the electronic control signal, for example the number of milliamperes (mA) , representing a required braking force. Electronic braking systems have the advantage that they can be controlled both manually and automatically by controlling the size of the control signal and, in the case of manual control, the size of the electronic signal can be controlled by the degree of activation of the relevant braking control device, for example the position of the brake pedal. A problem with this type of braking system is, however, that the control range of the electronic control signals must be calibrated correctly so that a particular activation of the braking control device results in a required braking force.

It is, however, the case that different machines, including machines of the same type, require different calibrations of the size of the electronic signal in order for a required braking action to be obtained. This depends, among other things, on tolerances in different mechanical parts. In order to find the correct hydraulic braking pressure, a control signal value is calibrated that consists of the value when the wheels start to rotate when the machine is raised on blocks. A problem with this calibration is, however, that it is time-consuming. There is thus a need for an improved method for the calibration of the electronic braking control signal.

OBJECT OF THE INVENTION AND ITS MOST IMPORTANT FEATURES An object of the present invention is to provide a method and a device that makes possible an effective and accurate calibration of the electronic braking control signal and that thereby solves the abovementioned problem.

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 15.

According to the present invention, a method is provided for the calibration of an electronic braking system for a machine and/or a vehicle. The method comprises the steps of generating a control signal that generates a high braking force by means of the said braking system, of generating a positive motor torque for the generation of an arbitrary propulsive force acting upon the said machine and/or vehicle with a gear selected, of reducing the said applied braking force by means of the said control signal until the said braking force essentially corresponds to the said propulsive force, and of storing a parameter value representing the said control signal value that represents the braking force that essentially corresponds to the said propulsive force, and of determining a control range for the said control signal for the said braking system on the basis of the said measured parameter value. The control signal can, for example, consist of a current or voltage .

This has the advantage that, by determining only one single control signal value for one single arbitrary propulsive force, a control signal range can be determined for the whole control signal range in which a change in the braking force is obtained, that is the interval that is delimited by the control signal that generates essentially 100% or maximal braking force and the control signal that generates 0% or essentially no braking force. Due to the fact that the applied propulsive force is arbitrary, it does not make any difference whether this corresponds to 10%, 32%, 67% or any other proportion of the total braking force that can be obtained from the braking system, provided that the applied propulsive force lies within the braking force range that can be obtained. By determining the control signal value that generates essentially 0% braking force, the braking control device, for example a brake pedal, can be "preloaded" so that the braking starts to take effect without delay.

The above steps can be carried out for at least two different propulsive forces. This has the advantage that a gradient for the control signal can be determined, so that no such gradient needs to be known in advance.

The above steps can be carried out for at least three different propulsive forces, with the said at least three different determined control signal values being used to determine a non-linear control range by interpolation. This has the advantage that a very precise brake characteristic can be determined, even for non-linear systems. In addition, this enables the effect of a braking control device on the said control signal to be calibrated, for example, in such a way that the brake action can be in an essentially linear relationship to the braking control.

In addition, a determination of the inclination of the surface upon which the vehicle is standing and the weight of the vehicle can be carried out, with the propulsive force generated by the said incline and weight of the vehicle being added to the abovementioned propulsive force. This has the advantage that the said determination of the control signal range can also be carried out on an inclined surface, with a downward incline adding propulsive force and an upward incline subtracting propulsive force.

The present invention also relates to a device, a computer program, a computer program product, a rock drilling rig, a vehicle and a loader or truck. Corresponding advantages are also achieved with these parts of the invention.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described in greater detail in the form of an embodiment and with reference to the attached drawings, in which:

Figures la-b show schematically a vehicle in which the present invention can advantageously be used;

Figure 2 shows an exemplary method according to a first embodiment of the present invention;

Figure 3 shows an example of a braking control signal characteristic calculated according to the present invention;

Figure 4 shows another example of a braking control signal characteristic calculated according to the present invention; Figure 5 shows an exemplary method according to another embodiment of the present invention.

DESCRIPTION OF MODES FOR CARRYING OUT THE INVENTION

Figures Ia and Ib show a vehicle 10 from the side and from above respectively. The vehicle 10 consists of a loader with which the present invention can advantageously be used. The machine 10 comprises a scoop 11 and wheels 12-15, and a control unit 19, that controls various functions of the machine 10. In addition, the vehicle 10 comprises at least one braking system 16, that comprises means for retarding the wheels 12-15, with each wheel being able to be retarded individually or together with one or more of the machine's other wheels. In addition, the machine 10 comprises a motor 17, such as a diesel engine or an electric motor, that is arranged to convert motor torque output to a propulsive force acting upon the vehicle's driving wheels via a gearbox 18, with the driving wheels consisting, for example, of the pair of wheels 13, 15 as indicated, or alternatively the pair of wheels 12, 14 or all the wheels.

By the term motor torque output is meant in this description a force from the machine's motor that propels the machine. A positive motor torque output means that the motor generates a driving force that attempts to drive the machine in the machine's direction of movement, by means of fuel feed and selected gear.

Machines of the type shown in Figures Ia-Ib are often used for mining and tunnelling. These environments often expose machines to adverse conditions, for example, there is often a great risk of stones, boulders or rocks coming loose or falling and hitting the machine. This makes great demands on machine reliability and, as mentioned, it must be ensured that the machine can be stopped if, for example, a brake pipe is hit by a stone. For this reason, braking systems are often used that operate the opposite way to those of ordinary vehicles. One usual such braking system is a system where the braking action is obtained by a plurality of spiral springs that press the brake plates against the brake disks as a result of the spring force, with the springs being spaced out around the circumference of the brake disks at the radially outer part. The braking force applied by the springs against the brake disks is such that, in the event of the springs not being acted upon, that is in the event of a non-pressurized system, the braking force is maximal, that is the plates exert the maximal pressure on the brake disks. The action of the springs on the plates is controlled by the pressurization of a hydraulic pressure-activated hydraulic piston, which piston compresses the springs in the event of pressurization, which thereby reduces the pressure on the brake plates and hence the braking action of the plates on the brake disks. By controlling the hydraulic pressure, the size of the braking force can thus be controlled. It is thus also ensured that, in the event of a sudden drop in pressure, the action of the piston on the springs will cease, and the springs will thereby immediately exert maximal force on the plates. Redundant systems are thus not required. The pressure acting on the hydraulic piston for each wheel can be arranged to be controlled individually. An example of a system of the above type is the "Posi-stop" system from Clark-Hurth Components. However, braking systems of this type must be calibrated in order for the required braking action to be obtained. If the system is completely mechanical, the machine's braking control device, such as a brake pedal, is connected to a pilot valve, with the flow through the pilot valve being controlled by the position of the pedal. The flow through the pilot valve then controls a main valve which, in turn, generates a hydraulic pressure acting on the brake piston (or pistons), the size of the hydraulic pressure being dependent on the flow through the pilot valve. The calibration is carried out by, with the machine raised up on blocks, the flow through the pilot valve in the event of a completely released pedal being adjusted manually by means of an adjusting screw to a flow that generates a brake piston pressure on the springs, which in turn results in the plates precisely being released from the brake disks (this is in order to avoid contact, with the risk of subsequent overheating of the brakes) . This "preloading" means that the brakes start to take effect immediately when the pedal is depressed, instead of the pedal needing to be depressed a little way before the pressure has dropped sufficiently (that is, before the brake piston has moved a sufficient distance) for the springs to start to press the plates against the disks. In addition, a corresponding pressure is calibrated for the maximal braking force. This calibration is carried out, however, by "trial and error", that is, an assumed value is set manually, then the machine is test-driven. If the result is not right, the value is corrected, and so on until the required action is obtained, a procedure that can thus be very time-consuming. The two calibrated pilot valve flows thus define the flow range within which the braking system is active.

If the system is electronic, an electronically-controlled valve is used, instead of the abovementioned pilot valve, to generate the said pilot pressure. The electronic valve is controlled by a control signal, with the braking force being adjusted by controlling the size of the said control signal. The electronic valve can, for example, be current-controlled and calibration is then carried out by calibrating an applicable current range that provides a pilot flow corresponding to the abovementioned pilot flow. In the case of an electronic braking system, the position of the brake pedal is converted to a value (for example a current size as described above) instead of the brake pedal acting directly upon a pilot valve. An electronic braking system has the advantage that it can be controlled by means of a control system and thus also makes possible remote control of the machine. The current for full braking force is set in the same way as described above, that is by random setting followed by test driving, etc. In this case a current range is thus determined instead, within which the braking system is active.

Thus, in both the abovementioned cases, the calibration is time-consuming. In addition, the machine is raised up on blocks, which can in itself be time-consuming, considering that a machine of the type shown in Figures la-b can weigh 30-40 tonnes. The calibration should also be carried out at certain intervals during the life of the machine, among other things due to the fact that brake disks or other components such as springs become worn or weakened and affect the braking function. In addition, a new calibration must be carried out whenever any part of the braking system is replaced, as differences in replaced parts due to mechanical tolerances can change the required pressure parameter values or current parameter values.

The present invention provides a simplified calibration method for electronically-controlled braking systems that makes raising the machine up on blocks unnecessary and also speeds up the calibration by utilizing an automated method. As will be recognized, the electronic braking system can be controlled by any unit for the control signal, for example voltage, but will be exemplified below in the form of a current-controlled system.

A first method according to the present invention is shown in Figure 2. Instead of setting current values according to the method above, according to the invention, a current is determined that corresponds to a particular braking force. The method commences in step 20 with the vehicle standing on a flat surface with started control system, started motor and activated parking brake and with the gears in the neutral position. When it is determined that a braking calibration is to be carried out, for example by an operator entering an appropriate command to the machine's control system via a display or a keyboard, the process continues to step 21 in which the parking brake is released at the same time as a high service braking force is applied. In this case, full braking force is applied (that is, the control signal current is set to 0 mA. For reasons of safety, a low current value can be used for full braking force and a high current value for low braking force, as a drop in current would then lock the brakes instead of releasing them) . The operator then selects in which direction the calibration is to be carried out, that is forwards or reverse, after which, in step 22, the operator or the control system selects the appropriate gear (forward/reverse) and an output of a particular positive motor torque. This will generate a propulsive force acting upon the machine's driving wheels. The propulsive force can consist of any percentage of the braking force that can be generated by means of the braking system, for example 1% or more of the maximal braking force that can be generated. In step 23, the applied braking force is then reduced gradually by the control unit 19 gradually increasing the current strength, for example by 10 mA at a time, with the speed of the vehicle being read off after each increase in current. Step 23 continues until the speed of the vehicle is greater than zero. The speed of the vehicle can be detected by detecting a wheel movement, for example by means of a rotation sensor. Instead of detecting wheel movement, rotation of an outgoing shaft can, for example, also be detected, or movement in relation to a surface, for example via a sensor acting against the surface.

When a wheel movement is detected, the braking force can be determined, as it then corresponds to the driving force acting on the wheel. The applied driving force for a particular gear and a particular motor speed is known and can, for example, be stored in a computer memory in or connected to the control unit 19, in which, for example, a table of gears and motor speeds and corresponding drive wheel force (propulsive force) can be stored. Thus, information about the drive wheel force for a particular gear and a particular motor speed can be made available to the control unit 19 in a simple way, whereby the braking force when the wheels start to rotate can also be determined directly. By storing a parameter value representing the current value of the control signal at the point when the wheels start to rotate, this "point" can be used to calibrate the braking system, which is carried out in step 24, in which the parking brake is reactivated and the current parameter values for 0% service brake (that is the vehicle moving freely) and 100% service brake (maximally-applied service brake force) are calculated. In the method shown in Figure 2, only one point is calculated, which means that in order to be able to calculate the calibration curve, the gradient of this curve must be known, that is how the braking force changes with the size of the control signal current. This gradient is often linear and can, for example, be specific to the type of machine and can be stored in the control system, or alternatively it can be specific to the individual machine and can be calculated and entered in the control system before the machine leaves the factory.

Figure 3 shows an example of a control signal characteristic in which the point A indicates the point calculated according to the above, that is a driving force applied with 1st gear selected, as can be seen in the figure. Due to the fact that in this case the gradient of the control signal is known and due to the fact that the braking force at point A as a percentage of total braking force is known, the points B

(control signal current for an unbraked machine (0% braking force)) and C (control signal current for maximal (100%) braking force) can thus be calculated. The machine's maximal braking force can be calculated during the production stage by knowledge of the spring characteristics and the friction between brake plate and brake disk, and will then be available to the control unit 19 for the abovementioned calculation. In order to ensure that the plates are released from the brake disks, the value calculated for the point B can be increased slightly, for example by a predetermined offset of 25 mA. The present invention has thus the advantage that calibration of a suitable control signal range can be carried out directly on a flat surface without having to carry out any complicated and time-consuming raising on blocks. In addition, the invention has the advantage that the range can be determined automatically and with good accuracy, as the current for full braking force can also be calculated and does not need to be found by an operator by trial and error. In addition, the greater simplicity of the method according to the present invention means that the probability of a new calibration being carried out after the machine has been operating for a certain period of time is increased considerably, which avoids the disadvantage associated with the known technology where the reluctance to carrying out a new calibration means that, due to wear of the braking system, the driver needs to depress the brake pedal a longer and longer distance in order for the braking to start to take effect, which results in a poorer reaction time and makes it more difficult to retard the machine smoothly and safely. The calculated characteristic can then be used in remote control of the machine, where an operator or a computer can request a required braking force, for example as a percentage, that is then converted according to the calculated curve to a corresponding control signal current. If the machine is being driven by an operator, the position of the brake pedal is converted to a corresponding current instead, (the position of the brake pedal can, for example, be obtained by means of a sensor that detects the angle of the pedal) , that is, according to Figure 3, if the brake pedal is depressed by 60%, a control signal value of about 550 mA is obtained.

According to the above, the gradient of the control signal curve must be known in order for the points B and C to be able to be calculated. By carrying out the process described in Figure 2 for two different points, that is two different tractive forces, two points on the curve are obtained. This is exemplified in Figure 4 where the points A and B are determined according to the process according to the invention, with the point B being the same as that shown in Figure 3, and the point B comprising a propulsive force with 4th gear selected, with a lower braking force corresponding to the propulsive force with 4th gear selected as shown in the figure. Although Figure 4 shows two different driving forces for two different gears, the driving forces can, of course, be generated by two different motor speeds in the same gear. However, it must be ensured that the generated driving force does not exceed the maximal braking force. As two points are calculated, the gradient can also be calculated, for which reason this does not need to be known in advance with this embodiment .

It is, of course, also possible to calculate more than two points on the curve, which is of particular interest in the cases when the shape of the curve is non-linear and where several points mean that a more accurate estimation of the shape of the curve can be made. The more accurate the estimation that can be made, the more predictable will the machine (the brake pedal) appear to an operator. If the control signal characteristic is non-linear, the abovementioned maximum and minimum braking values are determined by interpolation. Determination of more than two points has thus the advantage that, even if the system is non-linear, a linear brake pedal action can still be obtained. Figure 5 shows a general flow chart for the calculation of any number of points, with the steps 50-53 corresponding to the steps 20-23 in Figure 2, but with a step 54 inserted in order to investigate whether more than one point is to be calculated, and, if this is the case, steps 55-57 are repeated, which correspond to the steps 51-53, until all the required points have been calculated, after which 0% and 100% values are calculated in step 58, linearly in the case of two points, or by interpolation in the case of three or more points .

The solution described above can, in addition, be used to diagnose braking system wear. For example, the gradient of the control signal curve, determined initially by the calculation of two points according to the above, can be stored and compared with a gradient calculated after a period of use during a calibration carried out on a later occasion. If the gradient has become considerably flatter with time, that is if essentially the same current is required for two different points, or if the current difference between the two points is considerably reduced since the last calibration, this indicates that some part of the braking system has become worn, for example the brake disks, and should be replaced. In this way, parts are prevented from becoming so worn that they cause damage.

The present invention can also be used to provide a progressive braking function. For example, by measuring a third point in the vicinity of the point for 0% braking force, for example 5% braking force, in addition to two points according to the above, the brake pedal action can, for example, be set so that with depression of the brake pedal to 20%, the braking force only increases to 5%, after which the braking force increases more steeply than if the curve had been linear throughout. This has the advantage that the driver can apply an initial pressure on the pedal, and then can quickly obtain a high braking force when required, by depressing the brake pedal further.

The invention has been described above for calibration on a flat surface. The invention can, however, also be used for calibration on an inclined surface, in which case the applied tractive force is compensated by the effect of the incline, which can be calculated simply by determining the angle of inclination of the surface using an incline sensor. With knowledge of the weight of the machine, the abovementioned driving force can be compensated by the effect of the inclined surface .

In addition, in the description above, the calibration has been requested by an operator. The calibration can, however, also be requested by the control system, for example after a particular number of hours of use, with the operator being informed of this and being able to ensure that the calibration is carried out while the machine is being driven in a suitable location.

In the detailed description above, the braking control device has been exemplified in the form of a brake pedal. The said braking control device can, however, consist of any braking control device such as a control in the form of a knob or a lever. In addition, the braking control can be arranged to be determined by the relevant position of the pedal, knob or lever, or alternatively by a compressive or tractive force acting on the said pedal or control.

Although the invention has been described above in association with a specific machine, it will be recognized that it is applicable for many types of vehicles/machines with electronic braking systems where a control signal range needs to be calibrated. The invention can thus be modified within the scope of the following claims.

Claims

1. Method for calibration of an electronic braking system for a machine and/or a vehicle, with the said machine and/or vehicle comprising a motor and a gearbox connected to the motor, with the said motor being arranged to generate a propulsive force acting upon the vehicle via the said gearbox, wherein a braking force generated by the said electronic braking system, that counteracts the said propulsive force, is being dependent upon an electronic control signal, with the size of the said generated braking force being controlled by the size of the said electronic control signal, characterized in that the method comprises the steps of:

- a) generating a control signal for generating a high braking force by means of the said braking system,

- b) generating a positive motor torque with a gear selected for the generation of a propulsive force that acts upon the said machine and/or vehicle,

- c) reducing the said applied braking force by means of the said control signal until the said braking force essentially corresponds to the said propulsive force, d) storing a parameter value that represents the said control signal value that represents the braking force that essentially corresponds to the said propulsive force, - e) determining a control range for the said control signal for the said braking system based on the said determined parameter value.

2. Method according to Claim 1, characterized in that the said generated propulsive force exceeds 1% of the maximal braking force that can be generated by means of the said braking system.

3. Method according to Claim 1 or 2, characterized in that the said propulsive force is generated by means of a motor speed exceeding the idling speed of the said motor.

4. Method according to any one of Claims 1-3, characterized in that the said propulsive force constitutes a proportion of the maximal braking force that can be generated by the said braking system.

5. Method according to any one of Claims 1-4, in which a known control signal gradient for the said electronic braking system is used for the said determination of the said control range.

6. Method according to any one of Claims 1-4, characterized in that, in addition, it comprises the step of carrying out the steps a) - d) for at least two different propulsive forces.

7. Method according to Claim 6, in which the said two determined parameter values are used for the determination of a control signal gradient, with the said determined gradient being used for the determination of the said control range.

8. Method according to any one of the preceding claims, characterized in that the steps a)- d) are carried out for at least three different propulsive forces, with the said at least three different determined parameter values being used to determine a non-linear control range by interpolation.

9. Method according to Claim 8, characterized in that, in addition, the method comprises the step of adjusting the effect of a braking control device on the said control signal in such a way that the brake action is in an essentially linear relationship to the braking control.

10. Method according to any one of the preceding claims, characterized in that the said determination of the said control range limits for the said control signal comprises a determination of the size of the control signal that essentially corresponds to the value at which a full braking force is generated, and the size of the control signal that essentially corresponds to the value at which no braking force is generated.

11. Method according to any one of the preceding claims, characterized in that it comprises the step of calculating the inclination of the surface upon which the vehicle is being driven and of carrying out a determination of the weight of the vehicle, with the propulsive force generated by the said incline and weight of the vehicle being added to the abovementioned propulsive force.

12. Method according to any one of the preceding claims, characterized in that the said size of the said electronic signal consists of a current level or a voltage level.

13. Method according to Claim 12, characterized in that a high signal level generates a low braking force and vice versa.

14. Method according to any one of the preceding claims, characterized in that the said vehicle consists of a mining and/or construction machine.

15. Device for calibration of an electronic braking system for a machine and/or a vehicle, with the said machine and/or vehicle comprising a motor and a gearbox connected to the motor, with the said motor being arranged to generate a propulsive force acting upon the vehicle via the said gearbox, wherein a braking force generated by the said electronic braking system, that counteracts the said propulsive force, is being dependent upon an electronic control signal, with the size of the said generated braking force being arranged to be controlled by the size of the said electronic control signal, characterized in that the device comprises:

- means for generating a control signal for generating a high braking force by means of the said braking system, - means for generating a positive motor torque with a gear selected for generating a propulsive force acting upon the said machine and/or vehicle,

- means for reducing the said applied braking force by means of the said control signal until the said braking force essentially corresponds to the said propulsive force,

- means for storing a parameter value that represents the said control signal value that represents the braking force that essentially corresponds to the said propulsive force, - means for determining a control range for the said control signal for the said braking system based on the said determined parameter value.

16. Device according to Claim 15, characterized in that the said generated propulsive force is arranged to exceed 1% of the maximal braking force that can be generated by means of the said braking system.

17. Device according to Claim 15 or 16, characterized in that the said propulsive force is arranged to be generated by means of a motor speed exceeding the idling speed of the said motor.

18. Device according to any one of Claims 15-17, characterized in that the said propulsive force constitutes a proportion of the maximal braking force that can be generated by the said braking system.

19. Device according to any one of Claims 15-18, in which a known control signal gradient for the said electronic braking system is arranged to be used for the said determination of the said control range.

20. Device according to any one of Claims 15-19, characterized in that, in addition, it comprises means for determining parameter values for at least two different propulsive forces.

21. Device according to Claim 20, with the said parameter values being arranged to be used for the determination of a control signal gradient, with the said determined gradient being arranged to be used for determining the said control range .

22. Device according to any one of Claims 15-21, characterized in that, in addition, it comprises means for determining parameter values for at least three different propulsive forces, with the said at least three different determined parameter values being arranged to be used to determine a non-linear control range by interpolation.

23. Device according to Claim 22, characterized in that, in addition, it comprises means for adjusting the effect of a braking control device on the said control signal in such a way that the brake action is in an essentially linear relationship to the braking control.

24. Device according to any one of Claims 15-23, characterized in that the said determination of the said control range limits for the said control signal comprises a determination of the size of the control signal that essentially corresponds to the value at which a full braking force is generated, and the size of the control signal that essentially corresponds to the value at which no braking force is generated.

25. Device according to any one of Claims 15-24, characterized in that it comprises means for calculating the inclination of the surface upon which the vehicle is being and for carrying out a determination of the weight of the vehicle, with the propulsive force generated by the said incline and weight of the vehicle being arranged to be added to the abovementioned propulsive force.

26. Device according to any one of Claims 15-25, characterized in that the said size of the said electronic signal consists of a current level or a voltage level.

27. Device according to Claim 26, characterized in that a high signal level is arranged to generate a low braking force and vice versa.

28. Device according to any one of Claims 15-27, characterized in that the said vehicle consists of a mining and/or construction machine.

29. Computer program for calibrating a control signal range for an electronic braking system in a vehicle and/or machine, characterized by code elements that enable the control unit to carry out the method according to any one of Claims 1-14 when they are executed in a control unit.

30. Computer program product comprising a computer-readable medium and a computer program according to Claim 29, with the computer program being stored on the computer-readable medium.

31. Rock-drilling rig comprising a device according to any one of Claims 15-28.

32. Vehicle comprising a device according to any one of Claims 15-28.

33. Loader or truck for transportation of mined rock in tunnelling or mining, comprising a device according to any one of Claims 15-28.