FI119184B - Controlling the crane position of the forestry machine while driving - Google Patents

Description

119184

CONTROLLING THE FORWARD CRANE POSITION WHILE DRIVING

The invention relates to a method for controlling the position of an articulated boom crane during transitions of a forestry machine according to the preamble of claim 1. The invention relates to a forestry machine according to the preamble of claim 13.

For harvesting, forestry machines are known to move in the field, such as harvesters, with a crane head fitted with a processing device, known as a harvester head, for cutting, felling, pruning and sawing a growing tree trunk to desired lengths. The harvester head has the necessary feeding and sawing equipment for handling the tree trunks. Sawn timber trunks are collected by another known off-road machine and its handling equipment, a loader with a grapple, and transported in its cargo space. Also known are combination machines which combine the functions of a harvester and a loader.

Typically, composite machines, harvesters and loading machines comprise two successive frame structures arranged by means of a frame joint to pivot about a vertical axis relative to each other and / or pivot about a horizontal axis relative to each other. On trucks, the front frame is usually supported by one pair of wheels or two swinging bogies -: *. · '* 25 structures, each with two wheels. The cab and power unit are usually located on the front frame. The rear frame is supported by ···· * 'typically two swinging bogie structures, each with two wheels. Alternatively, each wheel is attached to a rear frame by means of a self-supporting suspension such as in U.S. Patent 5,366,337 or 6,299,181.

· * · 30. · * ·. A load space and a crane, usually of the articulated type, whose outermost end usually comprises a telescopically operating assembly with its grabs, are located on the rear frame. F 'in the rear frame: The crane is most often mounted directly behind the frame joint,. 35 in front of the load carrier, while it is located behind the cab. One *; *; such a truck is a Timberjack ™ 101 OB or a Timberjack ™ 1110C.

:. * ·· The crane is located on top of the swivel, which allows 119184 2 to rotate the turret around the vertical axis when handling loads next to the load. When the crane is not in use, for example when driving a load carrier, it rests on the bottom of the load compartment or on the load on which the crane grapple, outer end or outer parts rest.

5 Typically, the crane grapple is stuck to either the uppermost timber frames or the bottom of the load compartment, to the rear.

The crane and its pivoting device may also be located at the rear of the front frame, where it is located on the cab or in front of the articulation joint, typically behind the cab, as in U.S. Patent 3,450,222. One such loader is the Timbeijack ™ 81 OB. Also in this case the outermost end of the crane rests in the load area during normal travel.

In harvesters, a crane is typically located at the front of the front frame 15 in front of the cab, and the power source is located at the rear frame. In some special devices, such as U.S. Patent Nos. 4,505,396 and 4,506,792, a processing unit is also located on the front frame, e.g. for pruning and trimming of tree trunks. Em. US patents also disclose means for directing a cab and a crane to work in the same direction. The direction of the harvester cab in the direction of the harvester rib is also discussed in EP 1 201 832 A1.

• • * a • a * a · ·

When transporting a load or traveling on an empty load truck ·. • on the road or on the road, the crane is usually not in use and • rests on a load • 25 or in the load space, even with the grapple not attached: anywhere.

a • · a • «· · · • · a

Combined forestry machines, which allow the crane on top of the rear frame to turn and forward over the front frame. 30 that backwards onto the load compartment could be used to cut trees. * ··· *. and pruning in front of the front body, which is at the same time the forward direction. In this way *. '** is formed a tramline for one-way driving, leaving the tree trunks in the terrain and returning in the opposite direction, but now with the rear frame in front, so that the crane would work on both • • ·. 35 sides and would load the tree trunks into the load space. Driving the front frame * · · * · up front would make crane control quite difficult, because during longer displacement • Y ·: the harvester head would have to be turned over the load compartment, and the 119184 3 again returned to the front frame without load. If the crane were pointing forward while driving, then during cranking and turning of the harvester and loader, the crane would point obliquely outward and extend out of the track so it would hit upright trees.

It is an object of the present invention to provide means by which the disadvantages caused by crane movement can be minimized or eliminated. Specifically, the purpose is to actively influence the behavior of the crane and, by means of steering, prevent crane collisions as the forestry machine moves.

During travel, the crane can be positioned automatically. In this case, the driver does not have to worry, for example, that the crane attached to the rear frame size will remain properly aligned with the size of the front frame 15 when the crane is pivoted above the front frame. An example is the case where the crane is directed forward and slightly tilted in the direction of rotation of the forest machine when cornering or changing direction. This reduces the overall width of the harvester and facilitates off-site handling.

20

The method according to the invention is characterized in what is stated in the characterizing part of claim 1. The forestry machine according to the invention is characterized in what is stated in the characterizing part of claim 13. Other advantageous embodiments of the invention are * *. *. Embodiments are disclosed in the dependent claims.

By means of the invention, the lateral movement of the entire crane, its outermost end, the grapple or any part of the ··· can be minimized. In the invention, the control of the crane turning device is dependent on the angular position 30 between the front frame and the rear frame. Unnecessary movement of the crane is also prevented when driving downhill. during and over obstacles. The invention is also useful when driving on a flat surface, because during bending, the center forces, too, cannot cause the crane to sway to the side even if the driving speed is high and the position of the forestry machine changes.

35 • · · *; * | In the invention, active steering is used and the crane is located in a desired position above the front frame with a tooling tool. The advantage is 119184 4 that in addition, during the bending of the implement, the operator does not have to constantly worry about turning the crane so that it does not collide with the growing trees adjacent to its passage.

5 The pressure medium control system is also easy to implement by using a small number of control valves that interconnect the control circuits of the pivoting and trunk joint pressure media systems and by controlling such valves with a forestry machine control system such as the Timberjack TMC ™ system.

10

The invention will now be described in more detail using, by way of example, a preferred embodiment, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a forestry machine in direct and direct driving; 1 Forestry machine while driving a curve and: 'When operating the crane actively, * Figure 4 shows Figure 1 from above, *. *** 25 when operating a crane and actively controlling the crane, and • · * * ·· · Figure 5 shows a missile system for active crane control.

«·· 30 Figure 1 shows a forestry machine that is both a load carrier and a j '. \\ harvester. Said forest machine 1 comprises a front frame 2 and a rear frame 3 interconnected by a frame joint 4, whereby the frames can be folded about a vertical direction and preferably also rotate about a horizontal direction which coincides with the size of the forest. 35 in the longitudinal direction 13, which in Fig. 1 is at the same time the driving direction 2 * · '* of the front frame. In some cases, the body joint 4 also allows the bodies to fold about a horizontal direction transverse to 119184 5 in the direction 13. The structure and function of the body joint 4 and the structure of the bodies are known per se.

In the forestry machine of Figure 1, the swinging bogies 5 and 6, 5 each carrying two wheels, and the swinging bogies 7 and 8, each carrying two wheels, support the front frame 2. The structure of the bogies is known per se and the number of wheels may vary as described above. The bogie can be replaced by independent wheel suspensions and the wheels can also be connected to tracks or replaced by tracks.

10

The front body 2 has a cab 9 and a rear crane 10 is connected to the rear body 3 via a turning device 11. The rear body 3 has a load 20 in front of which the turning body 11 is located. The pivoting device 11 forms a kind of pivot table on which the crane 10 is mounted 15 and can rotate about the vertical pivot axis. Thanks to the pivot, the grapple 12 of the crane 10 can be extended to the sides of the forestry machine 1, whereby the grapple 12 can be used to load or unload timber and logs. Preferably, the crane 10 is fitted with equipment that combines the functions of a harvester head and a loading grapple. In Figure 1, the nos-20 handle 10 comprises a vertical post 10a, a substantially horizontal boom 10b and an outermost boom 10c, which fold relative to the operative * 1 · 1, about a horizontal direction, and the outermost boom 10c is a three-piece Γ · 1. as well as telescopically operated with a working attachment at its head.: A tool such as a grapple 12. Alternatively, the crane only has three or four boom sections • ·· • V 25 and the grapple 12 is attached to the outermost: 1V. Column 10a is usually not tilt forward or * ·· 1 rearward.

♦ 2 · • · ··· ♦

In Figure 1, the outermost boom 10c is folded in the horizontal boom 10b ···. 30 so the end of the outermost boom 10c is this time closer to the rear .1 ···. the front 3 of the body as the rear. The grapple 12 can also be used to hold the * .1 'at the desired position of the cargo compartment 20, usually at its base: 1: 1 at 12b. The grapple 12 rests in the cargo compartment 20 on the rear frame 3 sec 'or on the load. Alternatively, the grapple 12 is located at a distance 1.5 above the station 9 at a distance from the front frame 2.

• · • · · · 2 2 2 119184 6

Fig. 1 also indicates the direction of travel 13 of the front frame 2, the direction of travel 14 of the rear frame 3 and the direction 15 of the crane 10, which in this case overlap when driven straight. The direction of the crane 15 also means the position of the horizontal boom 10b or the direction in which the grapple 12 is si-5, as viewed from the direction of the turning device 11. As can be seen, the crane 10 projects from the rear frame 3 forward.

Figure 2 shows what happens when a forest machine 1 is driven in a curve or when the forward direction of the front frame 13 changes. The situation also corresponds to 10 when the control system and the turning device 11 are provided with a free, inactive floating coupling, whereupon the centrifugal forces may cause the crane 10 to swing to the side. In this case, the direction of the crane 15 and the direction of the rear frame 14 remain the same, whereby the grapple 12 is substantially displaced from its original position 12a. This position also corresponds to that in which the pivoting device 11 is locked in a certain position as shown in Figure 1, so that during cranking the crane 10 is forced to turn sideways to the position shown in Figure 2. This is why locking is not a good option.

The amount of free oscillation of the crane 10, i.e. the angular position C of the direction 15 relative to the direction 13, varies and depends e.g. grapple with 12 effective forces. Similarly, crane 10 will swing sideways as · '· *: the tilted forest machine 1 is driven on a slope, even if it is driven directly. The reference position 12a of the crane 10 may also be offset from the center-25 line and the corresponding angular position of the pivoting means 11 is also a reference position or a 0 position for changes.

··· ···· · * .. '· Figure 3 illustrates a situation in which active float control is enabled and when the forestry machine 1 is driving a curve or driving direction 13 30, with the rear frame direction 14 deviating from the front frame direction. "·· *. 13 (angular position A) With active control of the turning device 11 *: ** the position of the grapple 12 deviates as little as possible from its original ··, · *: position 12a and the swinging or movement is prevented or restricted to the desired amount. If the position at which grapple 12 is located is further forward than in Figure 3, then the angular position C • * · between directions 13 and 15 is controlled to be smaller than in Figure 3. The change in direction 15 is thus greater than 1 to the starting position. At the same time, 119184 7 results in less boom end swing of the crane 10. The intersection of the directions 13 and 15 is preferably located at the point, or vertically, on the same line where the grapple 12 or part of the crane 10 is located in front of the front frame 2 to minimize the displacement movement. Alternatively or additionally, it may be chosen that the portion of the crane 10 which is furthest from the turning device 11 is held at line 13 or at most at a desired distance therefrom. This prevents the end of the crane 10 from moving to the side of the forestry machine 1 when making a tight bend. The angle of rotation of the pivoting device 11 of the crane 10 (rotation position B, which is the difference between directions 14 and 15) is dependent on the angle position between the bodies 2 and 3 (position A, which is the difference between directions 13 and 14).

The direction of rotation of the pivoting device 11 is also parallel to the direction of rotation of the front frame 2 or the articulation 4. It can be noted that the pivot angle B of the pivoting device 11 or its change is usually smaller than the pivot angle A of the front body 2 or the body joint 4 or its change. The dependence can be defined as a parameter X, which is the ratio of the angular position A to the angular position B. The dependence X can also be determined on the basis of the change in said angular positions with respect to the selected reference position. Alternatively, proportionality is determined by geometry, for example, based on which: a: *: The point of crane 10 is to be kept as close as possible to something · *. *. at a specific point in front of or above front 2. An example of such positions is grapple 12 and its reference position 12a. Comparison-25 can also be selected on an experimental basis. If necessary, i, t: can be defined such that the rotation angles A and B correspond to each other (X = 1), wherein the crane 10 is always parallel to the front frame 2. This · ***, ': is a viable option for short moves and working of the forestry machine.

30

When the forest machine 1 is driven directly, the active control **, ** purchase crane 10 will not swing to the side even when traveling in a parallel, *:: * or tilting position over an obstacle. The crane 10 is held in the desired reference position, i.e. the desired angle B. The 35 positions of the crane 10 are changed if at the same time the angular position of the frames: · **: changes.

• ·· • · 119184 8

Figure 5 shows a control system 18 for implementing a float. The crane pivoting device 11 is known per se and usually comprises two mechanical pressure medium controlled cylinders 11a and 11b which rotate a turntable structure on which the crane 10 is mounted or integrated with the crane 10. It is known, for example, to use a gear rack ( and 11 b) and a gear (at the turntable) combination.

The turning device 11 can, if desired, be connected to a so-called. free, non-guided float 10, for example by means of valves 18a, in a manner known per se. For example, this is an electrically controlled, normally closed, 2/2-way valve that opens the connection between the chambers at different ends of the same cylinder (11a and 11b). The control circuit of the pressure medium system 18b comprises the necessary pressure source, the tank and the controlled valve means. The pressurized fluid 15 is directed to the work chamber through piping and valves, and back to the tank or control circuit.

The system 18 includes an electrical control device 18c, which is preferably software-modifiable, which monitors the work machine and all 20 associated ancillary functions. In addition, the control device 18c reports the operation of the machine on the cab display, and various settings and adjustments, even driver-specific, can be stored in the system via the user interface 19. The control device 18c is also programmed to carry out the operation in accordance with the invention, which modification work itself will be apparent to those skilled in the art on the basis of this disclosure. Another embodiment of the invention: ···: the shape based on the use of sensors is easily implemented by modifications to the control device 18c alone. The turning device 11 is then controlled on the basis of the sensor information, but using valves known per se, e.g. the first proportional-directional valve 30 of the pressure medium circuit 18b, controlling the access of the pressure medium to the actuators. The pressure medium in turn provides the actuator * ·; · *.

* • · · • · · ♦ ··. ***. In the first embodiment of the invention, the actuators 4a, 4b (e.g. cylinders) of the body joint 4 and the actuators 11a, 11b of the turning device are, if desired, in series with the pressure medium circuit 18d of Fig. 5, using e.g. electrically operated, normally closed, 2 / 2- 119184 9 directional valves (and 3/2 directional valves), wherein the second proportional directional valve of the stiffener 18b, which controls the operation of the frame joint 4, also controls the rotation position of the pivoting device 11. As the bodies 2 and 3 are rotated, the parallel actuators 4a and 4b move in different directions 5 and the angular position is changed. The actuators 4a and 4b may be mounted directly between the bodies 2 and 3, but the rotation is also achieved by actuating the actuators between the frame joint 4 and the pivotable body.

The dependence or mathematical relationship between the angular position and the rotation position is defined as parameter X to the control device 18c, where it can be changed and stored. In another embodiment of the invention, a separate circuit 18d is not required, but the control device 18c controls the position of the crane 10 depending on the angle-15 position by means of the aforementioned proportional valve. Angle position is determined by means of sensors, for example. In the first embodiment, the dependence X is bound and based solely on the configuration of the pressure medium system 18d or the dimensioning of the components. When the actuators 4a (or 4b) and 11a (or 11b) are series-connected cylinders, the gear ratio, i.e., parameter X, is selected by minimizing the surface area of their pistons, taking into account the displacement volume flows. The ratio X corresponds, for example, to position 12b of Figure 3. If the ratio is to be changed, the circuit 18c can either: v. reducing or increasing the volume flow (smaller *. /. turn) to the turning device 11. Suitable control valves, for example power distribution valves, are used for control. According to a third embodiment of the invention, the control device 18c controls the ... T volume flow in the above manner. Most preferably, this ratio can be determined: ***: freely, either by means of the control device 18c or by adjusting the components 18d, depending on the type of crane 10 and the desired operation.

30

Various positions of the crane 10 may be selected in the control device 18c, which also determines the aforementioned proportionality. If desired, the crane 10 may also be driven, manually or automatically by the control system 18, to a reference position 35 with respect to which changes in rotation position 15 are effected. · *. * ·: The reference position is, for example, according to Figures 1 or 4. If the bodies 2 and 3 are then folded, the control can take this into account by means of the sensor 119184 10 and compensate for the misalignment relative to the position shown in Fig. 1. The driver switches active buoyancy on or off as desired using, for example, the user interface 19.

Figure 4 illustrates an embodiment of the invention such that the change in the rotational position of the crane 10 corresponds to the change in the angle between the frames 2 and 3. The crane 10 stays parallel to the frame 2 and pivots in the direction of pivoting, inner curvature or curvature. In the situation shown, the crane 10 is also often extended far, whereby any part 10 or grapple 12 of the crane 10 is in danger of colliding with trees growing next to the tramline if the invention were not applied.

It should be noted that the invention is particularly useful in a situation where the forest machine 1 is driven or reversed in front of the rear frame 3. This makes it more difficult for the driver to observe the movements of the crane head 10 when the crane 10 is oriented in the direction opposite to the direction of travel as shown in Figure 4 and the driver looks over the rear frame 3 in the direction of travel. With active steering, the crane 10 can be properly and safely turned, either in the position shown in Figure 3 or in Figure 20.

; . ·. Figure 5 also shows sensors 16 and 17, which are not mandatory in the first, first, embodiment of the invention. The control system 18 \ \ monitors the angle or position between the frames 2 and 3, for example by means of a signal from an angle sensor 25 or a position sensor 17. The position can be determined: · by the position of the frame joint 4 or its individual cylinder 4a or 4b, or by any other suitable part. The position of the crane 10 is determined on the basis of a signal from the angle or position sensor 16, whereby it is known in which position it is. The transducer 10 may be already positioned above the front frame 2, but may be so that the crane 10 is extended '** outside the front frame 2, whereupon it must first be brought to the top of the front frame 2, · *. * To the desired reference or initial position manually or automatically. The reference position usually corresponds to the · · 35 direction 15 in Figure 1. For control 19, either the desired ratio X or the quantity * is determined; * · The location of the crane 10 is to be held. If the crane 10 or grapple 12 has one or more constant positions in which 11,119,164 are rotated, a specific predetermined ratio X can be selected for each constant position. necessary. However, the sensor 16 enables the position of the lift 10 to be checked and to monitor whether the crane 10 has reached the correct position during control, and thus automatic export to the initial position is also possible.

The crank position 15 of the crane 10 is preferably changed simultaneously 10 when the chassis 2 and 3 are pivoted so that, for example, the grapple 12 moves as little as possible. The crane 10 is kept stationary when the positions of the bodies are not changed.

The modifications or additions required to the control system 18 may be accomplished by one skilled in the art based upon this disclosure and may be modified depending upon the particular design and type of forestry machine being employed. The type and mode of operation of the sensors 16 and 17 are selectable and depend on the type of pivoting device 11 or the articulated joint 4. Almost any sig-20 signal obtained which describes the angular positions of the bodies 2 and 3 and the angle difference between them is suitable.

«· · • * *

The invention is not limited to the above embodiment, but may be implemented within the scope of the appended claims.

• · · • «* **« · • · φ ·· · · * * · • * • ·

• M

• · Φ · · · m m m m m m m m m m m m m • # Φ • · Φ φ Φ

Claims (19)

119184 A method for controlling the position of an articulated boom crane during transitions of a forestry machine, the method comprising at least the following 5 steps: driving a forestry machine (1) comprising a front frame (2), a rear frame (3), a hinge (4) between said frames driving ai-10 hen, articulated boom crane (10) mounted on the rear gon (3) of a turning device (11) which allows the crane to be rotated about a vertical direction and thereby changing its rotational position (B), 15. changing the position of the forestry machine (1) during driving such that the angular position (A) between the front frame (2) and the rear frame (3) is changed, characterized in that: said rotary device is automatically controlled during driving, so that when said angular position is also changed, said rotation position when said • · \\ rotation position or its change is dependent (X) on said / " 25 angles or changes in angular position. A method according to claim 1, wherein the rear frame (3) comprises a load carrier (20) for transporting the timber frames, and wherein the crane (10) and the tool (12) attached thereto are movable above and directed to the front frame (2). in the driving direction of the forestry machine (1). The method according to claim 1 or 2, wherein the translation is carried out. **. the crane (10) in the same direction as the front frame (2) is rotated. 35 ·:. '* I A method according to claim 1 or 2, wherein said dependence is maintained such that the desired position of the crane (10), which is 119184 above or in front of the front frame (2), or a tool (12) attached to the crane (10) in front of the front body (2), remains substantially stationary when said angular position is changed. The method according to claim 1 or 2, wherein said dependence is maintained such that the position and orientation (15) of the crane (10), when positioned above the front frame (2), remain substantially the same with respect to the position and orientation (14) of the front frame (3). ) when said angular position changes. 10 A method according to any one of claims 1 to 5, wherein: rotating the crane (10) by rotating said pivoting device, comprising first actuators (11a, 11b) that are controllable and exerting a cranking force on the crane 15 (10) and used to control the forestry machine (1) a control system (18) at which said dependency is set or stored, or at which point the crane (10) or tool (12) is to be substantially stationary. . The method of claim 6, wherein the met:: *! · 'Is changed. rotating the position of the adjusting machine (1) by said frame linkage, which comprises • second actuators (4a, 4b) which are controlled by said control system and which cause: ··: a force effect to rotate the frames (2, 3). • * · • · · A method according to any one of claims 1 to 5, wherein: the position of the crane (10) is rotated by rotating said pivoting means comprising first actuators (11a, ['V.' 11b) which are controllable and which cause the crane * ·; * ( 10) pivoting force,:, :): - changing the position of the forestry machine (1) by pivoting said frame linkage comprising other actuators (4a, ·, 35 4b) which are controllable and which cause the pivots (2, 3), 119184 is used to control the pressure medium circuit (18d), whereby the second actuators (4a, 4b) can be connected, if necessary, to the first actuators (11a, 11b) so that the control of the runner joint (4) causes the turning device (4). 11) 5 guidance, either constant or adjustable dependence (X). A method according to any one of claims 1 to 8, wherein: the crane (10) is automatically or manually moved to a position 10 which serves as a reference position (12a), either before or during travel, and automatically rotated (B) of the crane (10) relative to to that reference position, according to said dependency. 15 A method according to any one of claims 1 to 9, wherein a control system (18) is used for controlling, comprising a sensor (17) defining said angular position. A method according to any one of claims 10 to 10, wherein a control system (18) is used for controlling, comprising: a sensor (16) which defines said rotation position. The method according to any one of claims 11, wherein the y 25 is rotated in a direction opposite to where the rear frame (2) is rotated when the rear of the forestry machine (1) is reversed. (3) ... T above. • · · • · · · A forestry machine comprising: 30 y * t - a front frame (2), a rear frame (3), a hinge (4) between said trunks, allowing said trunks to rotate sideways while traveling, with the front frame (2) and angle (A) between rear frame (3) change,, ·. 35 - an articulated boom crane (10) mounted on a rear frame (3) * · * · to a pivoting device (11) which allows the said crane to be rotated about a vertical direction and thus to change its rotational position (B), first actuators (11a, 11b) for changing the position of said pivoting device, and 5. a control system (18) for controlling said actuators, characterized in that: 10. the control system (18) is further provided to automatically control said pivoting device on a forestry machine (1); during driving such that when said angular position is changed, said rotational position is also changed, wherein said rotational position or its change is further dependent (X) on said angular position or its change. The forestry machine of claim 13, wherein the rear frame (3) comprises a cargo space (20) for transporting the tree trunks, and wherein the crane (10) or tool (12) attached thereto is adjustable to rest on the bottom of the cargo space (20) or . • · · v • · 1 • · The forestry tool according to claim 13 or 14, wherein the steering system (18) is arranged to maintain the position and orientation (15) of the crane (10), or a specific position of the crane (10) or the working device attached to the crane: 1: The tool (12) is substantially stationary with respect to the front frame (2) when the angular position (A) of the met. • · · • 2 • · · 1 · A forestry machine according to any one of claims 13 to 15, wherein it comprises second controllable actuators (4a, 4b) for changing the position of said joint, and wherein the control system (18) comprises a pressure medium circuit (18d) by which the first actuators are if necessary, can be coupled to other actuators such that the control of the articulated joint (4): 3: at the same time causes the steering device (11) to be controlled, either constant * · 1. 35 or adjustable dependency (X). • · »• M • ·« • ♦ · 2 • · · 3 • ♦ 119184 A forestry machine according to any one of claims 13 to 15, wherein said control system (18) has said dependency, or a position on the rear frame (3), with respect to which the crane (10) or tool (12) is to be substantially stationary, or 5 selected. the position and orientation (15) of the crane (10) which is maintained substantially the same with respect to the position and orientation (14) of the front frame (2) as said angular position changes. The forestry machine according to any one of claims 13 to 17, wherein the control system (18) comprises a sensor (17) for determining said angular position. The forestry machine according to any one of claims 13 to 18, wherein the crane (10) comprises a reference position with respect to which said rotational position is arranged to change, wherein the reference position is selected from a particular constant position or a position in which the crane is respectively set. * • · · 1 · · »» · · · · 1 • · • I • 1 • t • »I * · • Φ II · • · · · • • • • • • • • • • • • • 1 • 1 • · * ··························································································· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 119184