FI20225273A1 - Method and system for controlling the crane of a working machine by using boom tip control - Google Patents

Abstract

The invention relates to a method for controlling a crane (22) on a work machine (1 0; 44) by means of tip control, in which method the crane (22) comprises at least two on the work machine (10; 44) and articulatedly mounted booms (24) , 26, 28), which are movable relative to the working machine (10; 44) and each other with actuators (32, 34, 36) which are controllable with a control system in the working machine (10; 44), and in which process the direction of movement and the speed of the crane tip (38) which is controlled by the user with control devices (50, 52) in the working machine (10; 44) is introduced by using movement speeds of different booms (24, 26, 28) in the crane (22). In the method according to the invention, the movement speeds of the various booms (24, 26, 28) in the crane (22) are determined automatically on the basis of at least one of the following factors: the position of the various booms (24, 26, 28) in the crane (22) relative the end position of their range of motion; the maximum force that can be reached with the crane (22); the position of the crane tip (38) relative to the working machine (10; 44); the location of obstacles in the surrounding environment relative to the crane (22). The invention also relates to a system for controlling the working machine's crane tip with tip control. Fig. 1

Description

METHOD AND SYSTEM — MACHINE TOOL BOOM

FOR STEERING WITH TIP STEERING.

Field of invention

The object of the invention is a method for controlling the boom of a work machine with tip control. The object of the invention is also a system that controls the boom of a work machine in accordance with the method according to the invention.

Background of the invention

Nowadays, the boom assembly attached to the work machine is still mostly controlled in such a way that the actuator connected to each boom of the boom is controlled separately from each other. Because of this, the user has to combine the movements of different actuators in order to make the boom move as desired.

In general, booms are used to move some work tool attached to the end of the boom. For example, a forest machine has a harvester head or a loading bucket as a work tool, depending on whether it is a harvester or a loading tractor.

This also depends a lot on which are the most typical movements that are usually carried out on the boom while working with the machine. In a loader used for loading trees, the boom is usually moved from the loading space of the loading tractor to the side of the log stack and back to the loading space.

When felling trees with a harvester, the tree trunk is usually moved in a horizontal direction from the work machine towards the trees to be felled and after felling to a suitable direction, where the pile of cut and pruned trees is placed.

In general, all work machines, also non-forest machines, have a boom

However, the goal of N movements is to move the work tool at the end of the boom

Moving from one place to another. Perhaps precisely because of this, recently 3 methods of controlling > 30 booms have been developed that better serve this goal and thus make the work of the machine operator easier. Here the so-called in tip control (or coordinated

I in control) the user controls the boom so that with the controls of the machine

N the movement of the boom head in different directions is controlled directly. Here

N one control function of the controller is used to control the head of the boom to move, e.g. in a horizontal direction, away from the working machine and back to the working

N 35 towards the machine, with the second control function vertically up and down, and with the third control function the entire boom turns horizontally to the left and right. This so-called tip control is used

motorically less demanding for the operator, because when using it, the user does not have to control different actuators separately and know how to connect the ratio of the movements of the individual booms produced by them to the movements of the boom head, but the machine's control system does it automatically according to the direction of movement the user wants the boom head to move. Because of this, the tip control has been found to make the work of a less experienced machine operator easier and more efficient. Such currently known boom control method and equipment based on tip control is described

Markus Saarela's diploma thesis "Coordinated control of a timber crane"

Usually, the boom comprises two to three booms that are hingedly or otherwise movably attached to each other and to the machine. For example, the forest machines manufactured by the applicant typically have a lifting boom hinged at the first end to a turntable attached to the body of the working machine in a pivoting manner, a folding boom hinged at the other end of the lifting boom and an extension boom that can be moved from the other end of the folding boom linearly in the lengthwise direction of the folding boom out and back into the folding boom. If, for example, a boom like this is controlled with a tip control, the control system can select an infinite number of alternatives in principle to implement a movement in a certain direction of movement. Depending on where the head of the boom moves in relation to its range of motion, some of these alternatives are always those whose implementation leads to a situation where moving the boom is more difficult than implementing another alternative due to one or some factors limiting the movement of the booms. These are not taken into account in the currently known control methods based on tip control

N restrictions caused by the operating principle of the boom, hence the current ones

Booms operating with N tip steering are not always able to move the 3 ends of the boom as desired. This can mean, for example, that the head of the boom does not agree to move at all when > 30 in a certain position, if it is attempted

I steer in the direction in which the control system finds itself in a situation,

N where it would have to move some actuator, even though this is e.g.

N in its extreme position or where a boom would hit the work machine, the ground or some other surrounding obstacle. In such a situation, the user

N 35 has to move the boom first in a suitable direction, in which the tip control can move the boom, so that the work can continue.

Brief summary of the invention

The purpose of the invention is to provide a new type of method for controlling the boom of a work machine with tip control so that the movement of the boom does not stop or the movement of the boom end is not prevented or complicated even in those situations when the boom end is controlled in such an area where one or some of the actuators that move the boom are at the extremes of their range of motion or where the boom end location or the location of known obstacles around is such that they prevent moving the head of the boom in its range of motion in the desired direction or using the movements of certain booms. In addition, the purpose of the invention is to bring forth a system that works in accordance with the method according to the invention for controlling the boom of a work machine.

The purpose of the invention is achieved by a method and a system in which the control system in the machine, which controls the movements of the boom end of the machine with tip control, is programmed to operate in such a way that it selects the movement speeds of the different booms of the boom based on predetermined factors, so that the desired movement direction and speed of the boom head is realized in different booms that are suitable for the situation using the movement speeds of the booms, or that the impossible movement direction of the boom head at a certain point or in a certain area is automatically replaced by a suitable movement direction close to this direction of movement, in which case the user does not have to manually perform the necessary change of movement direction because the boom cannot move in that direction of movement or the movement is slower than normal. More precisely, the method according to the invention is characterized by what is presented in independent patent claim 1 and the system by what is presented in independent

N in patent claim 17. Independent patent claims 2-16 and 18

N show some advantageous 3 embodiments of the method and system according to the invention. a 30

I The advantage of the method and system according to the invention is that the

Controlling the boom of the machine when using the tip control according to N

N becomes faster and easier, because the movement of the boom end is not hindered or made difficult, even if a boom of the boom is at the extreme end of its range of motion, a boom

N 35 is in a position from which, due to a known surrounding obstacle or other reason, it cannot move further in the direction in which moving the head of the boom in the desired direction would require, or if the head of the boom is movable

mass in a direction that would lead to a collision risk, for example. Thanks to this, the user does not have to make extra movements manually to avoid these situations, in which case the use of the boom becomes easier and faster compared to tip control implemented in a known way.

According to the first aspect of the method according to the invention, when the jib boom comes a predetermined distance closer to the extreme end of its movement range, its movement speed is limited.

According to the second aspect of the method according to the invention, when the position of at least one boom comes a predetermined distance closer to the extreme end of its movement range, the movement speed of at least one other boom is increased.

According to the third aspect of the method according to the invention, the portion of the movement of the booms that realize the movement of the boom head at the highest possible speed is weighted.

According to the fourth aspect of the method according to the invention, the portion of the movement of the booms that realize the movement of the boom head with the lowest possible energy consumption is emphasized.

According to the fifth aspect of the method according to the invention, the contribution of the boom that implements the movement of the head of the boom with the greatest possible force is emphasized.

According to the sixth aspect of the method according to the invention, boom

The direction of movement of the N head is changed from the direction of movement controlled by the user to the automatic

N tically so that the direction of movement of the boom head deviates from the user's goal.

S

> 30 According to the seventh aspect of the method according to the invention if

I the movement of the boom head controlled by the user cannot be carried out is controlled by the

The end of N misto to move in a direction different from this.

OF

N According to the eighth aspect of the method according to the invention if

N 35 the operator guides the head of the boom in a horizontal direction towards the machine, the head of the boom is automatically raised to the predetermined minimum height during the movement.

According to the ninth aspect of the method according to the invention, if the user steers the end of the boom vertically closer to the predetermined minimum distance from the working machine, the end of the boom is simultaneously moved away from the working machine during this movement.

According to the tenth aspect of the method according to the invention, if the user steers the end of the boom (38) upwards at least a predetermined maximum distance, the end of the boom is simultaneously moved in the direction of the work machine.

According to the eleventh aspect of the method according to the invention, the working machine is a forest machine equipped with a loading space and that the boom comprises a lifting boom hinged to the working machine at its first end, a folding boom hinged at the first end to the other end of the lifting boom, and a folding boom movable outwards and inwards to the folding boom at its other end in the longitudinal direction attached extension boom.

According to the twelfth aspect of the method according to the invention, when the end of the boom is inside the load space, the movement speed of the extension boom is limited.

According to the thirteenth aspect of the method according to the invention, when the end of the boom is at a predetermined distance from the load space, the movement speed of the extension boom is limited.

According to the fourteenth aspect of the method according to the invention

N tip control is switched off in one or more of the following ways when

N boom end is within a certain area or is moving to reach a certain area; 3 Automatically, with a control function provided by a separate controller or > 30 by maintaining a control function that controls another function for a predetermined time x.

N According to the fifteenth aspect of the method according to the invention, tip control a is automatically switched back on when the head of the boom moves a certain

Outside the N 35 area.

According to the first aspect of the system according to the invention, the control system of the work machine comprises a data processing unit for controlling the movements of the boom with a program that can be programmed into the data processing unit, and that the control element is a program stored in the data processing unit.

Description of drawings

In the following, the invention is explained in more detail by referring to the attached drawings, in which figure 1 shows a loader whose boom is controlled using the method according to the invention, figure 2 shows a principle diagram of the control levers in the cab of the loader tractor according to figure 1 and the control functions they provide to control the boom of the loader tractor according to figure 1, and Figure 3 shows a harvester whose boom is controlled using the method according to the invention.

Detailed description of some preferred embodiments of the invention

The method and system according to the invention can be applied in many different working machines equipped with a boom, such as, for example, different excavators and forestry machines. In forest machines, the method can be used well, e.g. in loader tractors 10 as shown in figure 1 and harvesters 44 as shown in figure 3. Most typically, the actuators used to move the different booms of the boom in the work machine are hydraulic cylinders, but in principle they could also be other linear actuators.

N kinds of actuators, such as compressed air cylinders or spindle motors. In addition

N e.g. to move the rotary table 3 that turns the boom horizontally, actuators producing rotary movement, such as hydraulic > 30 or electric motors, can also be used. All these actuators can be controlled

However, I uses a controller equipped with a programmable data processing unit

N us system, which controls the movements of the boom placed in the cab of the machine

With the control functions given by the n controllers, so that the control system a modifies the given control function into the desired form of one or some work

In the N 35 machine, the control command that causes the movement of the actuator.

The forest machine shown in Figure 1 is a loader tractor 10, which is intended for transporting felled tree trunks out of the forest. In the rear part of the frame 12 of the load tractor 10, there is a load space 14 formed in the space between the banks 16 for transporting tree trunks. The front part of the load tractor 10 has a drive motor 18 and a cab 20, with control and management devices. Inside the cockpit is e.g. the left and right hand control levers shown in figure 2.

In this loader tractor 10, the boom 22 intended for handling tree trunks is between the cab 20 and the loading space 14. The boom 22 consists of a lifting boom 24, a folding boom 26 and an extension boom 28. The boom 22 is attached to the frame of the loader 12 by means of a turntable 30 that turns with respect to an axis vertical to it, so that it can be turned sideways with respect to the frame 12 around the loader 10 from left to right and vice versa. The lifting boom 24 is hinged at its first end to the turntable 30 so as to be able to pivot with respect to the horizontal axis.

The folding boom 26 is hinged to the other end of the lifting boom 24 and the extension boom 28 is fitted to the end of the folding boom in a movable manner in its longitudinal direction, so that it can move from the end of the folding boom to the end of the folding boom and back inside the folding boom 26 according to its range of motion. Between the lifting boom 24 and the turntable 30, the lifting boom 24 and the folding boom 26, and the folding boom 26 and the extension boom 28, there are hydraulic actuators 32, 34 and 36 that function in a known manner, with which the lifting boom 24 can be turned in relation to the turning table 30, the folding boom 26 in relation to the lifting boom 24 and extension booms 28 moves the folding boom 22 from the inside to the outside and back to the inside.

At the end 38 of the boom 22 is a loading grapple 40, which has gripping members 48 in the usual way, which are turned towards each other or away from each other

N with the actuator belonging to them, so that the loading grapple 40 can be gripped

N to one or more tree trunks to transport them to the desired location. 3 The loading grapple 40 can also be turned with the rotation device 42, > 30 in it, so that the tree trunks in the loading grapple 40 can be brought into a suitable position x when loading them, for example, into or out of the loading space 14.

N The loading tractor 10, the boom 22 and the loading grapple 40 are controlled from the cab 30 placed in the front part of the frame 12. Oh-

In N 35 compartment 30, various controls known per se are placed for this purpose, such as, for example, the left-hand control lever 50 and the right-hand control lever 52 shown in Figure 2, as well as the rocker levers 54 and 56 in these, which can be used to control e.g.

the movement of the boom 22 and the closing and opening of the grippers of the loading grapple 40 at the end of the boom 38 with the control functions that are achieved with the help of these controls. During steering, the control commands consisting of the control functions provided by the left-hand control lever 50 and the right-hand control lever 52 are transferred from these controls along the data transmission paths to the data processing unit in the control system, which actually takes care of the actuators 32, 34 and 36 that provide the functions of the boom 22 and the actuator that controls the opening of the loading grapple and for controlling the rotation device 42 by means of the electro-hydraulic control valves in their hydraulic circuits.

Figure 3 shows a harvester 44 equipped with a corresponding boom. In it, the control of the boom 22 is otherwise implemented in a similar way, but for the control of the harvester unit 46, more control functions that can be obtained with different controllers are needed. Some of them can be implemented using separate controls from the left-hand control lever 50 and the right-hand control levers 52 shown in Figure 2. However, there is no need to present these in more detail in this presentation, because the object of interest is only the control of the boom 22, which is implemented in the same way in the forest machines according to Figures 1 and 3.

Tip steering is used to control the boom 22 of the loader tractor 10 according to Figure 1 and the harvester 44 according to Figure 3. Thus, when controlling the boom 22 with the controls in the cockpit, especially the left hand control lever 50 and the right hand control lever 52, the desired direction of movement of the boom head 38 can be determined. To implement this control system

A program is programmed into the N data processing unit, which calculates different booms li-

The necessary movement speeds for the N-pointing actuators 32, 34 and 36 using kinematic equations so that the desired movement direction and speed > 30 of the boom head 38 are realized as well as possible. In this context, however, there is no need

I presents the kinematic equations and control technology required by tip control,

N because currently known solutions can be applied in that respect. Hence

In the method according to the invention, the calculation a of the boom kinematics can be carried out e.g. in the manner presented in Markus Saarela's diploma thesis, i.e. based on e.g. Denavit-Hartenberg notation. Control technical solutions may also be known today, because they can be used to control the boom programmatically, i.e. using control commands based on the above-mentioned kinematic calculations (i.e. control currents fed to the control valves).

The factors used in the method according to the invention (i.e. the criteria) are implemented in the loader tractor 10 according to Figure 1 and the harvester according to Figure 3 for the tip control of the boom 22 in such a way that when a certain criterion is met, the desired direction of movement of the boom head 38 or the way it is performed (i.e. which booms the movement is carried out with) is changed according to the criteria in accordance with.

In other words, the automatically functioning corrective functions modify certain booms of the boom 22 or the control command controlling certain booms 24, 26 and 28 and/or how the travel speeds of the individual booms obtained as a result of the calculation are assigned to different booms. This is done programmatically in the data processing unit of the machine's control system based on where the end of the boom 38 is located and what is the position of the different booms 24, 26 and 28 of the boom 22 relative to each other.

In the loader tractor 10 according to Figure 1 and the harvester according to Figure 3, the control of the boom 22 with the tip control takes place with the controllers 50 and 52 according to Figure 2 in the following way in normal situations (i.e. when the control system does not modify the control commands provided by different control functions): When turning the left-hand control lever in the direction of 50 +Yv moves the end of the boom 38 in a horizontal direction away from the machine.

Similarly, by turning the left-hand control lever 50 in the direction -Yv, the end of the boom 38 moves in a horizontal direction towards the machine.

When turning the same lever to the side in the +Xv direction, the end of the boom 38 moves laterally to the right, and when turning the lever in the -Xv direction, the end of the boom

N 38 moves laterally to the left. Right hand joystick 52 directions

When moving N +Yo, the end of the boom 38 moves vertically upwards, and when turning in the 3 direction -Yo, the end of the boom 38 moves downwards. These control > 30 functions in a suitable way at the same time by implementing the work machine

I user gets a loading grapple attached to the end of the boom 38 or

N harvester heads to move in the desired direction at the desired speed.

N For example, tilt the boom end diagonally away from the implement and to the left

When moving N, the machine operator turns the left control lever diagonally

N 35 to the left and forward (i.e. in the direction between directions +Yv and +Xv).

The speed of movement of the boom head 38 under normal conditions is directly proportional to how much the control lever is turned in the direction of the control function that produces the movement in question. The boom controlled in accordance with the method according to the invention moves exactly as directed by the user, however, only when there is no obstacle to moving the head of the boom in the direction of movement controlled by the user. In addition, in the method according to the invention, the distribution of the movement of the head of the boom to the individual booms, i.e. in the case of the boom 22 of Figure 1, to the lifting boom 24, the folding boom 26 and the extension boom 28 is automatically adjusted based on factors (criteria) that depend on the position and location of the boom 22.

In the following, programmatic changes to the movements of the loader tractor 10 shown in Figure 1 and the boom of the harvester shown in Figure 3 are shown as examples:

If any movement of the boom 22 boom approaches its end limit (which is typically caused by the limitation of the movement range of the actuator moving it), its speed starts to be limited well in advance (within a certain distance from the end limit of the movement in question). This distance depends on the structure of the boom and the lengths of the booms. The deceleration can also happen gradually in a ramp-like manner.

When the speed of one boom slows down, the movement speed of the other booms is correspondingly increased so that the movement direction and speed of the boom head desired by the user is realized. Increasing the speed of other booms/one other boom can happen in the same ramp-like manner as slowing down a boom approaching its end limit. This feature is valid for all booms in the boom set 22, i.e. lifting boom 24, folding boom 26 and extension boom 28.

N A more specific example than the previous one is a situation where there are 50 loading grapples

N is brought closer to the machine from afar. First, all booms are in use, i.e. 3 lifting boom 24, folding boom 26 and extension boom 28. When extension boom 28 comes > 30 close to its end limit, a certain limit distance away from it, we start to slow down its movement z. In order to keep the speed of the head 38 of the boom 22 constant,

N is increased according to the speed of the lifting boom 24 and the folding boom 26. When

N extension boom 28 has moved completely inside folding boom 26, the movement is continued a only with lifting boom 24 and folding boom 26. & 35

In general, it is possible to achieve the desired movement speed of the boom head 38 with several different speed combinations of different booms. In these cases, it is possible to select different weights for the use of the different booms 24, 26 and 28 and thus the actuators 32, 34 and 36 that move them. The choice of weighting devices can be influenced, for example, by the maximum possible movement speed of the boom head 38, smooth use of the boom, the relative strengths of the actuators 32, 34 and 36 and the need to keep the boom 22 in a favorable position for the following movements.

Regarding these, there are basic rules in the program programmed into the control system, which work in very different situations.

For example, the prioritization of different boom movements (i.e. different actuators) implemented in the harvester 44 according to Figure 3 is as follows: 1. The aim is to move the extension boom 28 inside the folding boom 26 as quickly as possible, when the end of the boom 38 is moved towards the machine. 2. When the end of the boom 38 is farther from the machine than the predetermined maximum limit distance, it is attempted to be lowered using the lifting boom 24 and the lowering movement performed with the folding boom 26 is limited. 3. When the end of the boom 38 is farther than the predetermined maximum limit distance, the aim is to raise the end of the boom 38 using the lifting boom 24 so that the lifting movement performed with the folding boom 24 is limited accordingly.

In some situations, the movement limits of the actuators 32, 34 and 36 moving the boom 22 and the geometry of the boom 22 prevent the head of the boom 38 from moving in the desired direction. In these cases, the aim is to find a movement direction on top of the boom 38 that does not deviate too much from the desired movement direction and which leads to the boom 22 going around the movement obstacle. This is implemented in such a way that, when deviating from the desired direction of movement, the head 38 of the boom is guided to move

N slower than usual (i.e. than the normal movement corresponding to this movement speed

N speed). The transition between these two operating modes is also implemented 3 smoothly. An example can be mentioned the situation where the end of the boom 38 > 30 is controlled to move upwards near the column. First the boom end 38

I can be moved straight up, but when the extension boom 28 comes

In the corner of the folding boom 26, a straight upward movement is impossible.

N The situation is corrected by using lifting boom 24 or folding boom 26. a The resulting trajectory deviates from the desired one, but boom 22 does not stop and

N 35 about the home situation? let's pass.

In tip steering, the machine operator determines the direction of movement of the boom head 38.

However, in the control of the boom end 38 according to the method according to the invention, the control system can interfere with this by changing the movement direction controlled by the controller, if it is appropriate. For example, in the harvester according to Figure 3, changes in the direction of movement are made in the following situations: 1. When the wood is brought closer to the machine near the ground, the end of the boom 38 is automatically raised to the level of the tire. This brings the possible tree at the harvester head to the optimal processing height. 2. If the end of the boom 38 is raised upwards closer to the machine than the prescribed minimum limit distance, its trajectory is changed to a slightly outward direction. This reduces the risk of collision with the machine. 3. If the end of the boom 38 is raised beyond the specified maximum limit distance from the machine, it can be brought closer to the machine at the same time (if there is no known obstacle to moving the end of the boom in this area). This gives a shorter lever arm for lifting the load.

The control method of the boom can also be changed based on a work phase.

An example of this can be shown is the control of the boom 22 of the loader tractor 10 according to Figure 1 when trees are unloaded from the load space 14 of the loader tractor 10: 1. Inside the load space 14, the extension booms 28 are not moved outwards at all, or only very slowly 2. When the user has selected a separate load unloading mode, the extension booms 28 nor is it moved when the end of the boom 38 is close, i.e. a certain safety distance closer to the machine.

OF

N Also in many other situations, the movement of the different booms 24, 26 and 28 can be 3 restricted as needed. For example, if one of the booms of 22 booms would be > 30 m into an awkward position, taking into account the surrounding known obstacles,

I can limit the movement of this boom and compensate for the desired movement

N on other booms.

OF

N The tip control according to the method according to the invention can also work as

N 35 that it switches off automatically, with a separate controller or some control function that controls another function by maintaining at least or at most a predetermined time while this function is in a certain state when the head of the boom is within a certain area or reaches a certain area in its movement. For example, in the loader tractor 10 according to Figure 1, such a function could be a control function that moves the extension boom into the folding boom when the extension boom is already fully moved into the folding boom and the loading grapple is e.g. close (within a predetermined maximum distance) to the edge of the loading space. In addition, the tip control according to the method according to the invention can be arranged to function so that it is automatically switched back on when the end of the boom moves outside a certain area.

Instead of the boom 22 used in the example applications presented above, the method according to the invention can be used in booms realized in different ways. In the case of more than three booms, the number of different options to achieve a certain movement direction and movement speed increases. On the other hand, if the number of interconnected booms is less than three (as in e.g. an excavator), e.g. a straight line movement cannot always be carried out and in this case the aim of the control may be to move the end of the boom using the closest possible direction of movement.

Functions according to the method according to the invention affecting the direction of movement of the head of the boom or individual booms or their execution method may also be programmed into the machine's control system other than those shown in the examples presented above. In some cases, the determining factor could be e.g. the lowest possible energy consumption (e.g. when the load tractor's loading grapple is moved empty) or the greatest possible force (when it is known that the wood in the loading grapple is very heavy), which can be achieved with the boom in question in connection with the movement.

OF

N The method and system according to the invention should therefore not be limited above

O to the presented example applications, but it can vary within the framework of the attached patent claims.

I a a

O

N.S

OF

LO

OF

OF

O

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Claims (18)

Patent claims: 1. A method for controlling the boom (22) of a work machine (10; 44) with tip control, in which the boom (22) comprises at least two booms (24, 26, 28) attached to the work machine (10; 44) and connected to each other in an articulated manner, which are moved to the work machine ( 10; 44) and the direction of movement of the boom head (38) controlled by the actuators (32, 34, 36) in the work machine (10; 44) and in which method by the controls (50, 52) in the user's work machine (10; 44) and speed is implemented using the movement speeds of the different booms (24, 26, 28) of the boom (22), characterized by the fact that the movement speeds of the different booms (24, 26, 28) of the boom (22) are determined automatically by the position of the controller (50, 52) and on the basis of at least one of the following factors: the position of the various booms (24, 26, 28) of the boom (22) in relation to the extreme position of their movement range; the maximum force that can be achieved with the boom (22); the location of the boom head (38) relative to the working machine (10; 44); the position of the surrounding obstacles in relation to the boom (22). 2. The method according to claim 1, characterized in that when one of the booms (24, 26, 28) of the boom (22) comes a predetermined distance closer to the extreme end of its movement range, its movement speed is limited. 3. The method according to claim 1 or 2, characterized in that when the position of at least one boom (24, 26, 28) comes a predetermined distance closer to the extreme end of its movement range, the movement speed of at least one other boom (24, 26, 28) is increased. OF 4. The method according to one of claims 1-3, characterized in that the portion of the movement of the booms (24, 26, 28) that realize the movement of the head of the N boom (38) at the highest possible speed is weighted. a 30 z 5. The method according to one of claims 1-4, characterized in that the portion of the movement of the N booms (24, 26, 28) that implements the movement of the N boom head (38) with the smallest possible energy consumption is weighted. N N 35 6. The method according to one of claims 1-5, characterized in that the boom (24, 26, 28) which moves the boom end (38) with the greatest possible force is weighted for the contribution of the movement. 7. The method according to one of claims 1-6, characterized in that the direction of movement of the boom head (38) is automatically changed from the movement direction controlled by the user so that the direction of movement of the boom head (38) deviates from the user's goal. 8. The method according to claim 7, characterized in that if the movement of the end of the boom (38) controlled by the user cannot be realized, the end of the boom (38) is controlled to move in a different direction. 9. The method according to claim 7 or 8, characterized in that if the user steers the head of the boom (38) horizontally towards the machine (10; 44), the head of the boom (38) is automatically raised to a predetermined minimum height during the movement. 10. The method according to one of claims 7-9, characterized in that if the user steers the end of the boom (38) in the vertical direction a predetermined minimum distance closer to the working machine (10:44), the end of the boom (38) is simultaneously moved away from the working machine (10; 44) during this movement. . 11. The method according to one of claims 7-10, characterized in that if the user steers the end of the boom (38) upwards at least a predetermined maximum distance, the end of the boom is simultaneously moved in the direction of the work machine (10; 44). 12. The method according to one of claims 1-3, characterized in that the working machine N is a forest machine (10) equipped with a loading space (14) and that the boom (22) N comprises 3 lifting booms (24) hinged to the working machine at its first end, the lifting boom (24) at the second from the first end > 30 of the hingedly attached folding boom (26) and to the folding boom (26) from its second I end the N extension boom (28) movably attached outwards and inwards in the longitudinal direction of the folding boom. N N 13. The method according to claim 12, characterized in that the movement speed of the extension boom (28) is limited when the head (38) of the boom is inside the load space (14). 14. The method according to claim 13, characterized in that when the end of the boom (38) is at a predetermined distance from the loading space (14), the movement speed of the extension boom (28) is limited. 15. The method according to one of claims 1-14, characterized in that the tip control is switched off in one or more of the following ways when the end of the boom is within a certain area or is moving to reach a certain area; Automatically, with a control function provided by a separate controller or by maintaining a control function that controls another function for a predetermined time. 16. The method according to claim 15, characterized in that the tip control is automatically switched back on when the end of the boom moves outside a certain area. 17. A system for controlling the boom (22) of the work machine (10; 44) with tip control, characterized in that the system comprises a control element for controlling the boom (22) according to the method according to one of claims 1-14. 18. System according to claim 17, characterized in that the control system of the work machine (10; 44) comprises a data processing unit boom (22) for controlling the movements of the data processing unit with a program that can be programmed and that the control element is a program stored in the data processing unit. N N O N O <Q O O I a a O NS N LO N N O N