Method for felling a tree by forest work machine and forest work machine

Abstract

A method for felling a tree by a forest work machine, in which method, determining a primary felling direction of the tree to be felled and at least one selection factor of the primary felling direction related to the primary felling direction, showing the primary felling direction graphically in the user interface of the forest work machine and, optionally, either felling the tree into the primary felling direction shown in the user interface the primary felling direction implementing at least one condition set by the selection factor of the primary felling direction or determining at least one alternative felling direction of the tree to be felled and felling the tree into one of at least one alternative felling direction. Additionally, a forest work machine which comprises a control system for determining the felling direction of the tree to be felled.

Description

[0001] Method for felling a tree by forest work machine and forest work machine

[0002] Background of the invention

[0003] The invention relates to timber harvesting and particularly to a method for felling a tree by a forest work machine and a forest work machine suitable for tree felling.

[0004] During timber harvesting, it is important to fell the trees as precisely as possible into the correct direction, especially in relation to trees to be left standing in order to prevent them from being damaged. The felling direction of a tree is determined by the rotation angle of a wood processing device, such as a harvester head, of the forest work machine used in tree felling, because said wood processing device of the forest work machine can typically tilt only into a specific direction in relation to the rotation angle of the wood processing device. The visual observation of this rotation angle is difficult for the operator of the forest work machine especially when the forest work machine is felling trees that are located several metres aside from the line determined by the longitudinal central axis of the forest work machine. Additionally, it is possible that the operator’s observations are also prevented by one or more trees to be left standing between the cabin of the forest work machine and the tree to be felled, which further makes the assessment of the felling direction of the tree to be felled more difficult.

[0005] Brief description of the invention

[0006] The object of the invention is to introduce a novel type of a method for felling a tree by a forest work machine and a novel type of a forest work machine.

[0007] The solution according to the invention is characterised by what is disclosed in the independent claims.

[0008] The invention is based on determining a primary felling direction of the tree to be felled and at least one selection factor of the primary felling direction related to the primary felling direction, showing the primary felling direction graphically in the user interface of the forest work machine and, optionally, either felling the tree into the primary felling direction shown in the user interface, when the primary felling direction implements at least one condition set by the selection factor of the primary felling direction or determining at least one alternative felling direction of the tree to be felled and felling the tree into at least one alternative felling direction. The solution according to the invention facilitates the assessment of the felling direction of the tree and minimizes the probability of the tree being felled into such a direction that it should not be felled for some reason. The presented solution is particularly usable in connection with intermediate felling, whereby the work environment of the forest work machine includes both trees to be felled and trees to be left standing and possibly other objects affecting the felling direction of the tree, such as rocks or boulders, which prevent or at least impair the sensory assessment of the felling direction of the tree to be felled or totally exclude one or more directions e.g. in order to prevent the trees left standing from being damaged.

[0009] Some embodiments of the invention are presented in the dependent claims.

[0010] Brief description of the drawings

[0011] The invention will now be described in greater detail by means of preferred embodiments and with reference to the attached drawings, in which:

[0012] Figure 1 is a schematic diagonal top view of a forest work machine,

[0013] Figure 2 is a schematic diagonal top view of a wood processing device of a forest work machine,

[0014] Figure 3 is a schematic view of a control system for controlling the operation of a wood processing device of a forest work machine,

[0015] Figure 4 is a schematic view of a method for controlling the operation of a wood processing device of a forest work machine, and

[0016] Figure 5 is a schematic view of a tree map formed of the environment of the forest work machine, which map describes the location of trees in the environment of the forest work machine in relation to the forest work machine, and

[0017] Figure 6 is a schematic view of another method for controlling the operation of a wood processing device of a forest work machine.

[0018] For reasons of clarity, some embodiments of the invention are illustrated in the figures in a simplified form. Similar parts are indicated in the figures by the same reference numbers.

[0019] Detailed description of the invention

[0020] Figure 1 is a schematic diagonal top view of a harvester 1 which is a forest work machine wherein the above-described solution can be applied. The harvester 1 comprises a chassis 2, which constitutes atleastpartofthe frame structure of the harvester 1 and into connection with which are arranged moving means 3, by means of which, the harvester 1 may move in relation to its work surface or work environment. Said moving means 3 are wheels in Figure 1, but generally said moving means can comprise at least one of the following: wheels arranged on an axle, wheels arranged on a bogie, a track system or some other means known as such to provide the movement of the forest work machine and to possibly change the position and / or direction of the movement of the forest work machine in relation to its work surface or work environment.

[0021] The harvester 1 further comprises a power source 4. The power source 4 can comprise e.g. a combustion engine, one or more electric motors and sets of batteries, and / or a generator or different combinations of these for generating the required power for providing the movement of the harvester 1 and for operating the devices arranged in the harvester 1.

[0022] The harvester 1 additionally comprises a cab 5. The cab 5 may be arranged foldably and / or rotatably in relation to the chassis 2. The cab 5 comprises required control means 6, by means of which, the operator of the harvester 1 may control the drive of the harvester and the devices arranged to it. Said control means 6 are shown very schematically in Figure 1 and they may comprise e.g. one or more manually controllable control means, such as e.g. a control lever, and / or one or more foot-controllable control means, such as e.g. a pedal. Said control means 6 can also comprise a pre-designed harvester work plan in the form of a runnable programme which is runnable by e.g. one or more harvester control units 7 very schematically shown in Figure 1 for controlling the drive of the harvester and the devices arranged in it. Said control unit 7 can be e.g. a computer or some other device or means comprising a microprocessor or some other microcontroller that is obvious to those skilled in the art.

[0023] The harvester 1 further comprises a boom 8. The boom 8 can be supported e.g. on the chassis 2 or a base connected to the chassis or some other part of the harvester frame or a part connected to it. The boom 8 may be arranged foldably and / or rotatably in relation to the chassis 2. The outmost end of the boom 8 includes a harvester head 10 forming the wood processing device of the harvester 1. The outmost end of the boom 8 and the harvester head 10 arranged to it by means of a hanger 9 constitute a tip of the boom 8.

[0024] The harvester 1 of Figure 1 constitutes a moving forest work machine equipped with a wood processing device, which is intended for performing the felling of trees, delimbing and / or debarking the felled tree and cross-cutting the trunk of the felled tree into parts of preferred length. Alternatively, the moving forest work machine equipped with a wood processing device can also be a combination of a forwarder and a harvester, whereby the forest work machine in question also comprises a load space for taking a load, typically parts of the trunk of the tree cross-cut to size, to be transported by the forest machine. Furthermore, the moving forest work machine equipped with a wood processing device may also be some other moving forest work machine suitable for felling trees and processing felled trees, such as e.g. a digger with a wood processing device fixed to its boom. In addition, the moving forest work machine equipped with a wood processing device may also be a forest work machine solely suitable for tree felling, whereby the wood processing device of the forest work machine only comprises means suitable for supporting and cross-cutting the trunk of the tree to be felled but not means required for processing the felled tree, such as delimbing and possibly also debarking the felled tree.

[0025] The forest machines of Figure 1 are typically forest machines operating based on the active control of the operator of the forest machine. However, it is also possible to apply the here presented solution in both semi-autonomously operating forest machines, whereby the forest machine can operate without the active control of the operator at least for some time, and in a substantially totally autonomously operating forest machine, whereby the operator does not actively contribute to the control of the forest machine operations without a special reason. The control means used for the control of the forest work machine can also be located separate from the forest work machine, whereby the control of the forest work machine is implemented by remote control. If the control of the forest work machine is totally implementable by remote control, the forest work machine does not necessarily include the cab 5.

[0026] Figure 2 schematically shows a diagonal top view of a harvester head 10 which may be used e.g. in the harvester of Figure 1 or in some other moving forest work machine at least for felling a tree. Figures 1 and 2 show the harvester head 10 turned into a position where it is typically when felling a tree. The harvester head 10 comprises a frame structure 10’ into connection with which a hanger 9 is arranged. Furthermore, into connection with the frame structure 10’, means intended for the felling of the tree and the processing of the felled tree fitted to the harvester head 10 are arranged. The means intended for tree felling and processing the felled tree typically comprise a feeding device 11, a delimbing device 13 and a cross-cutting device 15. The feeding device 11 is used for supporting the tree during felling and for feeding the tree in the harvester head 10 when processing the felled tree in the harvester head 10. The delimbing device 13 is used for supporting the tree during felling and for removing branches of the felled tree i.e. for delimbing the tree being fed by the feeding device 11 in the harvester head 10. The delimbing device 13 may also be used for debarking the tree. The cross-cutting device 15 is used for cross-cutting the tree being felled and for cross-cutting the tree being processed in the harvester head 10 into parts of preferred length.

[0027] The feeding device 11 of the harvester head 10 comprises movable feeding means which are pressed against the tree trunk for both supporting the tree being felled during the felling and for feeding the felled tree being processed by the harvester head 10 by using said feeding means in the harvester head 10. In the harvester head 10 of Figure 2, said feeding means comprise feeding rolls 12 provided with toothing directed outwards but, instead of the feeding rolls 12, the feeding means may be e.g. continuous feeding belts or chains of the tracked type.

[0028] The delimbing device 13 of the harvester head 10 comprises movable delimbing means which are pressed against the tree trunk for both supporting the tree being felled during the felling and for delimbing the felled tree being processed by the harvester head 10 when the felled tree 10 is being fed by the feeding device 11 in the harvester head 10. In the harvester head 10 of Figure 2, said delimbing means comprise both front delimbing knives 14a located in the direction of the front part 10a of the harvester head 10 in relation to the feeding rolls 12 and rear delimbing knives 14b located in the direction of the rear part 10b of the harvester head 10 in relation to the feeding rolls 12. The delimbing knives 14a, 14b are pressed using one or more actuators related to them against the surface of the tree for delimbing the tree being processed in the harvester head 10. Alternatively, the harvester head 10 can sometimes only comprise the front delimbing knives 14a. In addition to said movable delimbing knives 14a, 14b, the harvester head may also include fixed delimbing knives, either as separate knives fastened to the frame of the harvester head or as knives shaped on the frame of the harvester head, or further substantially fixed delimbing knives fastened to the frame of the harvester head delimbing knives which still can be somewhat elastic from the effect of a force applied to them either for the part of their fastening or their own structure. An example of this kind of knives is a top delimbing knife 14c schematically shown in Figure 2.

[0029] The cross-cutting device 15 of the harvester head 10 comprises one or more cross-cutting means, by using which, the tree being felled is both cross-cut at a preferred point and cross-cut into parts of preferred length when the felled tree is processed in the harvester head 10. In the harvester head 10 of Figure 2, the cross-cut means is constituted by a chain-saw-type cross-cut saw 16, of which cross-cut saw 16, its housing is visible in Figure 2, and which cross-cut saw 16 is used, by using one or more actuators related to it, both to the cross-cutting of the tree being felled and to cross-cutting the felled tree into parts of preferable length. The cross-cut saw can also be implemented as a cross-cut saw of the circular saw or rotary saw type. Instead of the cross-cut saw 16, the cross-cutting means can also be e.g. one or two moving cut off tools.

[0030] Typically, the harvester head 10 as well the feeding device 11, the delimbing device 13 and the cross-cutting device 15 therein are hydraulically operated devices, comprising actuators operating by means of substantially incompressible fluid pressure medium for controlling the operation of the feeding means of the feeding device 11, the delimbing means of the delimbing device 13 and the cross-cutting means of the cross-cutting device 15 by affecting the pressure and / or flow direction of pressure medium being fed to said actuators in a way known as such by those skilled in the art. As the electrical operation of work machines increases, at least part of said devices may also be implemented as electrically or electro-hydraulically operated, whereby their operation can be controlled e.g. by controlling the electric power fed to them or their actuators.

[0031] The harvester head 10 of Figure 2 is applicable for performing the felling of the tree, removing branches and, if necessary, also bark from the felled tree, and cross-cutting the trunk of the felled tree into parts of preferred length. However, the here presented solution is also applicable in such a wood processing device which is only applicable for felling a tree and not being capable of removing branches and possibly also bark from an already felled tree, which wood processing devices are also sometimes called felling heads of a forest work machine to separate them from harvester heads of a forest work machine also suitable for further processing the felled tree.

[0032] If the forest work machine is used solely for felling a tree to be felled, the harvester head does not necessarily comprise a feeding device and a delimbing device but they may be replaced for required parts by some other, at least one movable support means suitable for supporting the tree to be felled during felling.

[0033] Figure 3 schematically shows a control system 20 for controlling the operation of a wood processing device of a forest work machine. The example of the control system 20 shown in Figure 3 is particularly configured to control the operation of the harvester head 10 of the kind shown in Figure 2 but it is naturally configurable to control also other kinds of harvester heads or felling heads. The control system 20 of Figure 3 comprises a control unit 21 which is configured, as depicted in this description, to control the harvester head 10 and its operation and, if required, the operation of the forest work machine, that is e.g. the harvester 1 of Figure 1, and the boom 8 attached to it for controlling the felling of the tree. The control unit 21, of which there may be more than one, may be the same as the control unit 7 of the harvester 1 mentioned above, or the control unit 21 may be implemented as a part of the control unit 7 of the harvester 1 or the control unit 21 may be a control unit physically separate from the control unit 7 of the harvester 1 but functionally configured to work together with the control unit 7 of the harvester 1. The control unit 21 may be e.g. a computer or some other device or means comprising a microprocessor or some other micro controller, obvious to the those skilled in the art, which is configured to perform via a programme stored in the control unit 21, based on measurement or imaging data received by the control unit 21 and / or data further determined based on them, control measures affecting the operation of the harvester head 10, the forest work machine and / or the boom 8 in a manner known as such by those skilled in the art.

[0034] A control unit 21 of the control system 20 of Figure 3 is configured to control the operation of the feeding device 11 by means of a control connection CO- 11 and the operation of the delimbing device 13 by means of a control connection CO-13. The operation of the feeding device 11 and / or the delimbing device 13 may be controlled for pressing the movable feeding devices and / or movable delimbing devices against the trunk of the tree being felled for supporting the tree to the harvester head 10 for the duration of the tree felling. Furthermore, the control unit 21 is configured to control the operation of the cross-cut device 15 by means of a control connection CO- 15, such as the operation of the cross-cutting saw 16, for crosscutting the tree being felled. In addition, the control unit 21 may be configured to control the location and / or position and / or state of motion of the harvester 1, the boom 8 and / or the harvester head 10 in relation to the tree to be felled and / or each other by means of control connections CO-1, CO-8 and CO-10. Data or measurements 1M1, 1M8, 1M10 describing the location, position and / or state of motion of the harvester 1, the boom 8 and the harvester head 10 in relation to the tree to be felled and / or each other, which are provided by means of sensors arranged to them in modern forest work machines, may be transferred to the control unit 21 by means of corresponding data connections Ml-1, Ml-8 and Ml-10.

[0035] The control system 20 further comprises a user interface 22. The user interface 22 comprises the above-mentioned control means 6 for controlling the operation of the forest work machine and the wood processing device, the control of the operation of the forest work machine also comprising the control of the boom 8, if required. The control unit 21 is configured to control the operation of the forest work machine and the wood processing device to implement control measures performed via the user interface 22 at least according to the solution for determining the felling direction of the tree and for controlling the tree to be felled into said felling direction. Control information 1M22 to be delivered to the control system 20 via the user interface 22 may be transmitted to the control unit 21 by means of a data connection Ml-22.

[0036] The user interface 22 additionally comprises at least one display unit 23 which is configured to display at least graphically displayable data. The display unit 23 may comprise a display of e.g. a monitor or computer screen type, a head-up display to be reflected on the window of the forest work machine or a display formed by a virtual reality headset. The display unit 23 of the user interface 22 may also comprise a touch screen, via which, to the control system 20 may be fed by touching said screen at least data related to the control of the felling direction of the tree, which may be graphically displayed data produced on the touch screen.

[0037] According to the solution, the control system 20 is configured to determine a primary felling direction PFD of the tree to be felled and at least one selection factor SFXPFD related to the primary felling direction, the display unit 23 is configured to graphically display said primary felling direction PFD, and the control system 20 is configured optionally either to control the harvester head 10 to fell the tree into the primary felling direction PFD displayed in the display unit 23, the primary felling direction PFD implementing at least one condition set by the selection factor of the primary felling direction SFXPFD, or to determine at least one alternative felling direction AFDY of the tree to be felled and to control the harvester head 10 to fell the tree into at least one of the alternative felling direction AFDY.

[0038] The control system 20 is thus configured to implement a method wherein, for felling a tree by a forest work machine, a primary felling direction PFD for the tree to be felled and at least one selection factor SFXPFD related to the primary felling direction are determined, the primary felling direction is graphically displayed in the user interface 22 of the forest work machine and, optionally, either the tree is felled into the primary felling direction PFD displayed in the user interface 22, the primary felling direction implementing a condition set by the said at least one selection factor of the primary felling direction SFXPFD, or at least one alternative felling direction AFDY of the tree to be felled is determined and the tree is felled into one of the at least one alternative felling directions AFDY. Figure 4 schematically shows a method for controlling the operation of a wood processing device of a forest work machine according to the solution in question.

[0039] In the designation SFXPFD of the selection factor of the primary felling direction PFD, the letter "X" refers to the number of selection factors related to the primary felling direction, whereby "X" may obtain values 1, 2, n - 1, n, wherein n is the largest possible number of the selection factors of the primary felling direction relatable to the primary felling direction PFD and determinable for it. In the designation of the alternative felling direction AFDY, the letter "Y" refers to the number of alternative felling directions, whereby "Y" may obtain values 1, 2, ..., m - 1, m, wherein m is the possible largest number of determinable alternative felling directions AFDY. Figure 5, which shows a tree map TM determined of the work environment of the forest work machine, graphically displayed in the display unit 23 of the user interface 22, includes a schematically shown primary felling direction PFD, a first alternative felling direction AFD1 and a second alternative felling direction AFD2 shown by way of examples. The determination of the primary felling direction PFD and its selection factors as well as the determination of one or more alternative felling directions AFDY and the determination of the tree map TM are discussed in more detail later. However, said tree map TM is not a necessary means for graphically displaying the primary felling direction PFD in the display unit 23 of the user interface 22 but said primary felling direction PFD may be displayed in the display unit 23 of the user interface 22 to display the primary felling direction PFD of the tree also without said tree map TM.

[0040] The determining of the primary felling direction PFD and its graphical display in the display unit 23 of the user interface 22 produce information to both the control system 20 and the operator of the forest work machine on the direction into which the tree to be felled will primarily fall. The at least one selection factor of the primary felling direction SFXPFD related to the primary felling direction PFD again includes information which describes the suitability or acceptability of said primary felling direction PFD for the felling direction of the tree in relation to one or more previously set criteria, that is, a condition set by the selection factor of the primary felling direction SFXPFD, or in other words a condition set to the selection factor of the primary felling direction SFXPFD. If the determined primary felling direction PFD of the tree fulfils or implements at least one condition set by the selection factor of the primary felling direction SFXPFD to the primary felling direction PFD, the control system 20 may control, either by the confirmation of the operator of the forest work machine or without the involvement of the operator of the forest work machine in the control of the felling of the tree, the wood processing device to fell the tree into said primary felling direction PFD. If the determined primary felling direction PFD of the tree does not fulfil a condition set by the at least one selection factor of the primary felling direction SFXPFD set to the primary felling direction PFD, at least one alternative felling direction AFDY is determined to the tree to be felled and the control system 20 controls the wood processing device to fell the tree into one of the at least one alternative directions.

[0041] The presented solution is particularly usable in connection with thinnings, whereby the work environment of the forest work machine includes both trees to be felled and trees to be left standing and possibly other factors affecting the selection of the felling direction of the tree, such as rocks or boulders. The trees left standing may form visual obstacles which prevent or at least obstruct the sensory assessment of the felling direction of the tree to be felled or they may block totally one or more directions for felling the tree to be felled in order to prevent the trees left standing from becoming damaged. The presented solution facilitates the assessment of acceptable directions for felling the tree and decreases the probability of felling the tree into a direction which is not acceptable.

[0042] According to an embodiment mentioned above, said at least one alternative felling direction AFDY of the tree to be felled is displayed graphically in the display unit 23 of the user interface 22 of the forest work machine. However, it is still possible that the tree to be felled is felled directly into some determined alternative felling direction AFDY without displaying the alternative felling directions AFDY in question in the display unit 23 of the user interface 22 when the tree is not felled into the determined primary felling direction PFD.

[0043] According to an embodiment, at least one alternative felling direction AFDY is determined by the operator of the forest work machine. In this embodiment, the operator of the forest work machine determines at least one alternative felling direction AFDY to the control system 20 e.g. by a manually controllable control means pertaining in the control system 20, as a result of which, the control unit 21 of the control system 20 controls the wood processing device to fell the tree into one of said at least one alternative felling direction AFDY. The control system 20 may also display said at least one alternative felling direction AFDY graphically in the display unit 23 of the user interface 22.

[0044] According to an embodiment, at least one alternative felling direction AFDY is determined by the operator of the forest work machine such that the forest work machine operator determines to the control system 20 at least one alternative felling direction AFDY by drawing said at least one alternative felling direction AFDY onto the display unit 23 of the user interface 22 provided with a touch screen, as a result of which, the control unit 21 of the control system 20 controls the wood processing device to fell the tree into one of said at least one alternative felling directions AFDY.

[0045] According to an embodiment, the control system 20 comprises at least one imaging means 30 for imaging the work environment of the forest work machine, and the control unit 21 of the control system 20 determines based on said imaging at least one alternative felling direction AFDY and controls the wood processing device to fell the tree into one of said at least one alternative felling directions AFDY. Said at least one imaging means 30 may comprise e.g. at least one camera or video camera 31 and / or at least one radar 32 and / or at least one laser scanning device 33 which is configured to image the work environment of the forest work machine and to transfer by means of the data connection Ml-30 information 1M30 produced by imaging to the control unit 21 which is configured to determine at least one alternative felling direction AFDY based on the information 1M30 produced by imaging. Said imaging of the work environment of the forest work machine may produce the tree map TM already mentioned above and to be depicted in more detail in Figure 5 and in connection with its description.

[0046] In the above embodiments, the control system 20 is not configured to determine a selection factor of the felling direction related to said at least one alternative felling direction AFDY but, according to an embodiment, the control system 20 is configured to determine a selection factor of the alternative felling direction SFXAFDY relatable to at least one alternative felling direction AFDY, which selection factor of the alternative felling direction SFXAFDY is the same as the selection factor of the primary felling direction SFXPFD related to the primary felling direction PFD, and the control system 20 is further configured via the control unit 21 to control the wood processing device to fell the tree into an alternative felling direction AFDY implementing a condition set by the selection factor SFXAFDY of said at least one alternative felling direction. Equivalently as above, in the designation SFXAFDY of the selection factor of the alternative felling direction, the letter "X" refers to the number of selection factors related to each alternative felling direction AFDY, whereby "X" may obtain values 1, 2, ..., n - 1, n, wherein n is the largest possible number of the selection factors SFXAFDY relatable to the alternative felling direction AFDY and determined for it. According to an embodiment, the control system 20 is configured to determine the primary felling direction PFD of the tree to be felled and at least one selection factor of the primary felling direction SFXPFD related to the primary felling direction PFD and also to determine at least one alternative felling direction AFDY of the tree to be felled and at least one selection factor of the alternative felling direction SFXAFDY related to said at least one alternative felling direction AFDY which is the same as the selection factor of the primary felling direction SFXPFD related to the primary felling direction. Furthermore, according to this embodiment, the control system 20 is configured to determine the felling direction of the tree based on said determined selection factors SFXPFD, SFXAFDY of the felling direction and to control the wood processing device to fell the tree into a felling direction determined based on said selection factors SFXPFD, SFXAFDY of the felling direction.

[0047] In this embodiment, the final felling direction of the tree is thus selected from the group of the determined primary felling direction PFD and one or more determined alternative felling directions AFDY based on the same selection factors SFXPFD, SFXAFDY of the felling direction related to the felling directions in question. In this embodiment, the tree to be felled is not thus necessarily felled into the primary felling direction PFD even though the primary felling direction PFD implements at least one condition set by the selection factor of the primary felling direction SFXPFD related to the primary felling direction but, in any case, at least one alternative felling direction AFDY and at least one selection factor SFXAFDY of the alternative felling direction SFXAFDY related to it, which is the same as the selection factor of the primary felling direction SFXPFD, are determined. In this case, the final felling direction of the tree may be selected from the group of at least two possible felling direction by comparing the information contained by the same selection factor of the felling direction SFXPFD, SFXAFDY related to the felling directions in question, whereby the final felling direction of the tree may be selected based on said selection factors of the felling direction SFXPFD, SFXAFDY as the felling direction that best implements the selection factors SFXPFD, SFXAFDY.

[0048] A condition is determined for said selection factors of the felling direction whereby, when the felling direction in question fulfils the condition set by the selection factor related to it, the tree to be felled may be felled into said felling direction. If none of the felling directions implements the condition set by the selection factor of the felling direction determined, the tree may be felled into the felling direction the selection factor related to which is closest to implementation. The condition set by the selection factor of the felling direction may be e.g. a numerical target value which the selection factor of the felling direction in question must at least implement in order to be able to fell the tree into the felling direction corresponding said selection factor of the felling direction.

[0049] The selection factor of the felling direction SFXPFD, SFXAFDY of the tree may describe at least one of the following features or information depicting the felling direction: the felling direction being unobstructed, the felling direction being directed into an advantageous direction considering the efficiency of further processing of the tree, the felling direction being directed to the felling direction of a previously felled tree, or the natural falling direction of the tree.

[0050] The felling direction being unobstructed may be determined by imaging the tree to be felled and its environment and by determining features describing the tree to be felled and its environment based on the imaging. Imaging the tree to be felled and determining the features describing it may comprise e.g. determining the length of the tree and / or the number of branches in the tree and / or determining the location of the branches in the tree. The imaging of the environment of the tree to be felled and determining the features of the environment may comprise e.g. determining the location, that is, distance and direction, of trees surrounding the tree to be felled in relation to the tree to be felled and / or the number of their branches and / or the location of their branches. The imaging of the environment of the tree to be felled and the determination of the features of the environment may also comprise the determination of the location, that is, distance and direction, of other obstacles, such as rocks and boulders, in the environment of the tree to be felled in relation to the tree to be felled. Based on said features, it is possible to determine to the tree to be felled a selection factor describing the felling direction being unobstructed, which may describe e.g. if the tree fits for its length to fall into the intended felling direction and / or if the branches of the tree to be felled and / or the location and / or branches of other tree surrounding it or other obstacles prevent the felling of the tree into the intended felling direction. Then, e.g., the length of the tree to be felled may form a condition or a numeric target value that the intended felling direction must fulfil in terms of space reserved for felling in order to be able to fell the tree into said felling direction. Alternatively, based on the number of branches in the tree and / or the location of the branches in the tree to be felled as well as the number of the branches in the trees surrounding the tree to be felled and / or the location of the branches in the trees in question, it is possible to determine e.g. a numerical value describing the amount of space free from branches, whereby said amount of free space may form a condition or numeric target value the number of branches of the tree to be felled and / or the location of the branches in the tree and the number of branches of the trees surrounding the tree to be felled and / or the location of the branches in the trees in question must fulfil in order to be able to fell the tree to be felled e.g. between two trees to be left standing such that the trees left standing are not damaged.

[0051] The felling direction being directed into an advantageous direction considering the efficiency of further processing of the tree may refer to e.g. felling the tree substantially towards a vehicle path used for later collecting or parallel to it. This optimizes, based on the selected work method, the felling order of the trees, the point of delimbing, and the point and direction in which logs are cross-cut into a pile. In this case, the selection factor of the felling direction may be set e.g. a condition which describes the range of variation set for the felling direction, to an area corresponding which range of variation the felling direction should direct to implement the condition set for the selection factor of the felling direction related to the advantageous felling direction considering the efficiency of further processing of the tree.

[0052] Directing the felling direction into the felling direction of a previously felled tree may intensify both the felling step of the tree and the further processing step of the tree especially for the part of trees to be felled being next to each other. Then, the felling direction already once determined for the previous felled tree is very probably also a suitable felling direction for the tree to be felled next, whereby the forest work machine and its boom may substantially stay in the same location or position as when felling the previous tree and further processing the tree for delimbing and for cross-cutting the trunk of the tree.

[0053] If it is possible to utilize the natural falling direction of the tree as the felling direction, the power of the forest work machine used for felling the tree may be minimized when the tree is directed to fall into its natural falling direction. This again decreases the energy consumption of timber harvesting. Felling the tree into its natural falling direction might also be the best alternative from the viewpoint of safe felling because the tree might in any case fall into its natural falling direction despite trying to deviate the felling direction of the tree from its natural falling direction. The natural falling direction of the tree may be determined e.g. based on imaging the tree to be felled or on the determination of the position of the wood processing device having grabbed the tree to be felled like described later in more detail. Figure 6 schematically shows a method for controlling the operation of a wood processing device of a forest work machine, according to which method, in a control system, a primary felling direction of a tree to be felled and at least one selection factor of the primary felling direction related to the primary felling direction are determined and the primary felling direction is displayed graphically in a user interface of the forest work machine. In accordance with the method of Figure 6, in the control system, at least one alternative felling direction of the tree to be felled and at least one selection factor of the alternative felling direction related to said at least one alternative felling direction, which is the same as at least one of the selection factor of the primary felling direction related to the primary felling direction, are further determined, the felling direction of the tree is determined based on determined selection factors of the felling direction, and the wood processing device is controlled to fell the tree into a felling direction determined based on said selection factors of the felling direction.

[0054] According to an embodiment, the control system 20 is configured to determine the primary felling direction PFD of the tree to be felled and at least two selection factors of the primary felling direction SFXPFD related to the primary felling direction PFD and also to determine at least one alternative felling direction AFDY of the tree to be felled and at least two selection factors of the alternative felling direction SFXAFDY related to said at least one alternative felling direction AFDY which are the same as the selection factors of the primary felling direction SFXPFD related to the primary felling direction. The control system 20 is further configured to determine a combination of selection factors of the primary felling direction SFXPFD-C related to the primary felling direction PFD and a combination of selection factors of the alternative felling direction SFXAFDY-C related to said at least one alternative felling direction AFDY and based on said combinations of the selection factors of the felling direction SFXPFD-C, SFXAFDY-C the felling direction of the tree to be felled, and to control the wood processing device to fell the tree into the felling direction determined based on said combinations of selection factors of the felling direction SFXPFD-C, SFXAFDY-C. Principally, the felling direction that best implements the condition set for the combination of the selection factors of the felling direction SFXPFD-C, SFXAFDY-C is selected as the felling direction of the tree, but if the combination SFXPFD-C, SFXAFDY-C of the selection factors of none of the felling directions does not implement the condition set for the combination in question, the tree may be felled into the felling direction where the condition set for the combination of the selection factors of the felling direction SFXPFD-C, SFXAFDY-C is closest to implementation.

[0055] When using the combination of selection factors SFXPFD-C, SFXAFDY-C for determining the felling direction of the tree, one or more of the single selection factor may be selected such that the implementation of which in relation to the condition set to it is essential in order to be able to fell the tree into the felling direction related to the selection factor related to the felling direction in question.

[0056] The primary felling direction PFD may be determined in various ways. According to an embodiment, the control system 20 comprises at least one means for determining the position of the wood processing device and that the control system 20 is configured to control the wood processing device to grab to the tree to be felled, to determine the position of the wood processing device having grabbed the tree to be felled and to determine a primary felling direction PFD of the tree to be felled based on the position of the wood processing device having grabbed the tree to be felled.

[0057] The harvester head 10 of Figure 3 comprises a position sensor 10PO arranged to the harvester head 10 which indicates the position PO10 of the harvester head 10. The position sensor 10PO indicates the position PO10 of the harvester head 10 having grabbed the tree to be felled. The position of the harvester head 10 again indicates directly the felling direction of the tree because the harvester head 10 controls the tree to fall into substantially that direction where the moving feeding means of the feeding device 11 and / or the moving delimbing means of the delimbing device 13 pressed against the trunk of the tree are positioned in relation to the tree to be felled, possibly without considering a situation where the tree to be felled is large and in a strongly tilted position into some direction. It is also possible to observe this tilted position based on the position of the harvester head 10 indicated by said position sensor 10PO, whereby the position PO10 of the harvester head 10 having grabbed the tree may determine the primary felling direction PFD of the tree and said inclination direction of the tree may be interpreted as a possible alternative felling direction AFDY of the tree to be felled. Because the diameter of the tree can be determined by means of sensors measuring the position of the feeding means of the feeding device 11 and / or the delimbing means of the delimbing device 13 of the harvester head 10 having grabbed the tree, based on the tree diameter, it is possible to conclude the size of the tree and if it is possible to try to fell the tree in any other direction than the natural falling direction of the tree. In a situation, wherein the wood processing device has already grabbed the tree to be felled but the primary felling direction of the tree determined based on the position of the wood processing device does not fulfil a condition set by the selection factor of the primary felling direction related to it or a condition set by the combination of the primary felling direction and the tree will be felled in some alternative felling direction, the control system 20 is configured to determine a target position of the wood processing device implementing an alternative felling direction of the tree to be felled and to control at least one of the following for providing said target position of the wood processing device: the position of the wood processing device in relation to the tree to be felled, the position of the forest work machine or its boom in relation to the tree to be felled or the location of the forest work machine or its boom in relation to the tree to be felled.

[0058] If the tree to be felled is felled into an alternative felling direction instead of the primary felling direction, the wood processing device may be detached from the tree and turned into a new position in relation to the tree. In this case, at least the position of the wood processing device, but in some cases possibly also the location and / or position of the forest work machine and / or its boom, is changed to implement the alternative felling direction. If the alternative felling direction of the tree does not significantly differ from the primary felling direction indicated by the wood processing device having grabbed the tree, it is possible that the wood processing device having grabbed the tree can be kept fast in the tree in its original position but, by a small change in the location and / or position of the forest work machine and / or its boom in relation to the tree to be felled, it is still possible to control the tree to fall into an alternative felling direction, or the position of the wood processing device in relation to the tree is changed without detaching the wood processing device from the tree to be felled and, if required, also the location and / or position of the forest work machine and / or its boom in relation to the tree to be felled is changed. When changing the location and / or position of the forest work machine and / or its boom, the grab of the harvester head from the tree may be loosened if required, still keeping the position of the harvester head in relation to the tree substantially unchanged.

[0059] When the location and / or position of the wood processing device and / or the forest work machine and / or the boom is changed in relation to the tree to be felled, the position and / or location of the wood processing device and / or the forest work machine and / or the boom is changed in relation to each other. As feedback information, this control may utilize preinstalled sensors that modern forest work machines and their booms and possible also wood processing devices include, information 1M1, 1M8, IM 10 produced by which sensors may indicate the location, position and / or state of motion of the forest work machine and / or the boom and / or the wood processing device in relation to each other and which is produced to the control unit 21 of the control system 20 by means of corresponding data connections Ml-1, Ml-8 and Ml-10.

[0060] According to an embodiment, the primary felling direction PFD and at least one alternative felling direction AFDY may be determined already before the wood processing device is controlled to grab the tree to be felled. In this embodiment, the control system 20 comprises at least one imaging means 30 for imaging the tree to be felled, and the control system 20 is configured to imagine the tree to be felled, to determine based on the imaging at least one following piece of information describing the tree to be felled: centre of gravity of the tree or tilting direction of the tree, to determine based on at least one piece of information describing the tree to be felled the natural falling direction of the tree, to determine the natural falling direction of the tree as the primary felling direction of the tree and, optionally, either to control, when the primary felling direction implements a condition set by at least one selection factor of the primary felling direction, the wood processing device to grab the tree to be felled in a position which controls the tree to fall into the primary felling direction, or to determine at least one alternative felling direction of the tree to be felled and to control the wood processing device to grab the tree to be felled in a position which controls the tree to fall into one of at least one alternative felling directions.

[0061] In this embodiment, the primary felling direction PFD is determined in relation to the imaging of the tree and the centre of gravity TCG and / or the tilting direction TTD of the tree determined based on it. The decisive factor in the determination of the centre of gravity of the tree in relation to the primary felling direction PFD is the centre of gravity and / or tilting direction of the trunk of the tree, the effect of branches being typically quite minor in relation to the felling direction of the tree in at least substantially windless conditions. The imaging of the tree may be implemented by above-mentioned at least one camera 31, radar 32 and / or laser scanning device 33. At least one alternative felling direction AFDY of the tree may be determined by the operator of the forest work machine and / or based on the imaging of the environment of the forest work machine as described above. In this embodiment, the wood processing device may be controlled to perform the first grab of the tree to be felled already in that position which implements the falling of the tree into the selected felling direction, which can shorten the working time used for the felling and processing of the tree and decrease the energy consumption of timber harvesting.

[0062] As already described above, the primary felling direction PFD of the tree to be felled, like also at least one alternative felling direction AFDY, may be displayed graphically in the display unit 23 of the user interface 22 of the wood processing device as sole direction data without any point of reference to the environment of the forest work machine. As already briefly mentioned above, alternatively the primary felling direction PFD of the tree to be felled, like also at least one alternative felling direction AFDY, may be displayed in a tree map TM describing the environment of the forest work machine, which map is schematically shown in Figure 5 and which shows the location of at least the trees in the environment of the forest work machine in relation to the forest work machine.

[0063] In this embodiment, the control system 20 comprises at least one imaging means 30 for imaging at least partially the environment of the forest work machine in order to map the trees in the environment of the forest work machine, the display unit 23 is configured to display based on the imaging as a graphical presentation the tree map TM, which shows the location of at least the trees in the environment of the forest work machine in relation to the forest work machine, and the display unit 23 is configured to graphically display at least one determined felling direction in the tree map TM. In addition to the trees located in the environment of the forest work machine, the tree map TM may show some other objects that are observable in the environment of the forest work machine, such as rock or boulders or large stones, which might limit the selection of the felling direction of the tree. The tree map TM may also be accommodated into a map base formed of the area where said objects might already be presented. Also, the forest work machine may be shown in the tree map to illustrate the felling direction of the tree to be felled in relation to the forest work machine, like Figure 5 schematically shows.

[0064] The tree map TM schematically shown in Figure 5 thus describes the location of trees in the environment of the forest work machine in relation to the forest work machine. In the tree map of Figure 5, the locations of already felled trees 40 are shown by diagonal lines, sufficiently far from each other located trees to be left standing 41 are shown by horizontal lines and the crosswise diagonal lines show too densely located trees 42, of which, some must be felled. In a colour display unit, said trees may also be distinguished from each other by different colours. It is also possible to include information on the further processing value of the tree in the tree map TM. Trees with very high further processing value may also be distinguished from other tree by a separable marking, if preferred.

[0065] In the tree map TM of Figure 5, the trees 42, of which at least part must be felled, are shown distinguishably from the trees to be left standing 41. If the determined felling direction of the tree would cause the tree to be felled to fall against a tree to be left standing, the control system 20 may be configured to alternatively either warn about felling the tree into the felling direction shown in the tree map or prevent the felling of the tree into the felling direction shown in the tree map. The felling of the tree towards a tree to be left standing may still be implemented if the determination of the length of the tree to be felled shows that the tree will not reach the tree to be left standing when falling.

[0066] It is also possible to determine protective areas to the map base and / or tree map, which areas, the felling direction of the tree to be felled should not enter. The protective area may be determined e.g. around a tree to be left standing in order to maintain the tree undamaged, and the area around an exceptionally valuable tree may be determined larger than the one of the other trees. There may also be other grounds for determining protective areas, such as around a large boulder, a cliff, an electric power line, a road, or a parcel border. A protective area may also be determined to protect objects valuable of their nature or landscape value, such as e.g. a stream, a rill or a spring, or a shore, or a nesting place of a bird or some other animal, or a significant single tree to be preserved.

[0067] Those skilled in the art will find it obvious that, as technology advances, the basic idea of the invention may be implemented in many different ways. The invention and its embodiments are thus not restricted to the examples described above but may vary within the scope of the claims.

Claims

Claims1. A method for felling a tree by a forest work machine, which forest work machine comprises at least one wood processing device, which comprises a cross-cutting device for cross-cutting the tree to be felled, and a control system, which comprises at least one control unit, and a user interface, which user interface comprises control means for controlling the operation of the forest work machine and the wood processing device and at least one display unit for displaying graphically displayable information, and which control unit is configured to control the operation of the forest work machine and the wood processing device for implementing control measures performed by means of the user interface, and in which method determining in the control system a primary felling direction of the tree to be felled and at least one selection factor of the primary felling direction related to the primary felling direction, displaying the primary felling direction graphically in the user interface of the forest work machine, and that further in the control system determining at least one alternative felling direction of the tree to be felled and at least one selection factor of the alternative felling direction related to said at least one alternative felling direction, which is the same as at least one selection factor of the primary felling direction related to the primary felling direction, determining the felling direction of the tree based on the determined selection factors of felling direction, and controlling the wood processing device to fell the tree into the felling direction determined based on said selection factors of felling direction.

2. A method according to claim 1, characterized by determining and displaying graphically at least one alternative felling direction of the tree to be felled in the user interface of the forest work machine.

3. A method according to claim 1 or 2, characterized by determining at least two selection factors of the primary felling direction related to the primary felling direction and a combination of said selection factors, determining at least two selection factors of the alternative felling direction related to at least one alternative felling direction and a combination of saidselection factors which selection factors related to the alternative felling direction are the same as the selection factors related to the primary felling direction, determining the felling direction of the tree based on the determined combinations of the selection factors of the felling direction, and felling the tree into a felling direction determined based on said combinations of the selection factors of the felling direction.

4. A method according to any one of the preceding claims, characterised by grabbing the tree to be felled by the wood processing device, determining the position of the wood processing device having grabbed the tree to be felled, and determining the primary felling direction of the tree to be felled based on the position of the wood processing device having grabbed the tree to be felled.

5. A method according to claim 4, characterized by, when felling the tree into an alternative felling direction, determining a target position of the wood processing device implementing the alternative felling direction of the tree to be felled, and controlling at least one of the following for providing said target position: the position of the wood processing device in relation to the tree to be felled, the position of the forest work machine or its boom in relation to the tree to be felled or the location of the forest work machine or its boom in relation to the tree to be felled.

6. The method according to any one of claims 1-3, characterized by imaging the tree to be felled, determining based on the imaging at least one following piece of information describing the tree to be felled: centre of gravity of the tree or tilting direction of the tree, determining based on at least one piece of information describing the tree to be felled the natural falling direction of the tree, and that determining the natural falling direction of the tree as the primary felling direction of the tree, and controlling, when the primary felling direction implements the determined felling direction of the tree, the wood processing device to grab the tree to be felled in a position which controls the tree to fall into the primary felling direction, orcontrolling the wood processing device to grab the tree to be felled in a position which controls the tree to fall to one of at least one alternative felling directions.

7. A method according to any one of the preceding claims, characterized by imaging by at least one imaging means at least partially the environment of the forest work machine in order to map trees located in the environment of the forest work machine, forming to the display unit of the user interface of the forest work machine based on the imaging as a graphical presentation a tree map which shows the location of at least the trees in the environment of the forest work machine in relation to the forest work machine, showing graphically at least one determined felling direction in the tree map.

8. A method according to claim 7, characterized by showing in the tree map trees to be felled distinguishably from the ones to be left standing and, when the felling direction of the tree causes the tree falling against a tree to be left standing, alternatively warning about felling the tree into the felling direction shown in the tree map or preventing the felling of the tree into the felling direction shown in the tree map.

9. A method according to any one of the preceding claims, characterized in at least one of selection factors of the felling direction comprising at least one of the following pieces of information: the felling direction being unobstructed, the felling direction being directed into an advantageous direction considering the efficiency of further processing of the tree, the felling direction being directed to the felling direction of a previously felled tree, or the natural falling direction of the tree10. A forest work machine comprising at least one wood processing device which comprises a cross-cutting device for cross-cutting the tree to be felled, and a control system which comprises at least one control unit and a user interface, which user interface comprises control means for controlling the operation of the forest work machine and the wood processing means, and which control unit is configured to control the operation of the forest work machine and the wood processing device for implementing control measures performed by means of the user interface,characterized in that the user interface comprises at least one display unit for displaying information presentable graphically, determining in the control system a primary felling direction of the tree to be felled and at least one selection factor of the primary felling direction related to the primary felling direction, the display unit is configured to present the primary felling direction graphically, and that in the control system further determining primary felling direction of tree to be felled and at least one selection factor of primary felling direction related to primary felling direction, determining at least one alternative felling direction of the tree to be felled and at least one selection factor of the alternative felling direction related to said at least one alternative felling direction, which is the same as at least one selection factor of the primary felling direction related to the primary felling direction, determining the felling direction of the tree based on the determined selection factors of felling direction, and controlling the wood processing device to fell the tree into the felling direction determined based on said selection factors of felling direction.

11. A forest work machine according to claim 10, characterized in that the display unit is configured to receive and present graphically in the display unit at least one alternative felling direction.

12. A forest work machine according to claim 10 or 11, characterized in that the control system is configured to determine at least two selection factors of the primary felling direction related to the primary felling direction and a combination of said selection factors, determine at least two selection factors of the alternative felling direction related to at least one alternative felling direction and a combination of said selection factors which selection factors related to the alternative felling direction are the same as the selection factors related to the primary felling direction, determine the felling direction of the tree based on the determined combinations of the selection factors of the felling direction, and control the wood processing device to fell the tree into the felling direction determined based on said combinations of selection factors of felling direction.

13. A forest work machine according to any one of claims 10-12, characterized in that the control system comprises at least one means for determiningthe position of the wood processing device and that the control system is configured to control the wood processing device to grab the tree to be felled, determine the position of the wood processing device having grabbed the tree to be felled, and determine the primary felling direction of the tree to be felled based on the position of the wood processing device having grabbed the tree to be felled.

14. A control system according to claim 13, characterized in that the control system is configured, when felling the tree into an alternative felling direction, to determine a target position of the wood processing device implementing the alternative felling direction of the tree to be felled and to control, in order to provide said target position, at least one of the following: the position of the wood processing device in relation to the tree to be felled, the position of the forest work machine or its boom in relation to the tree to be felled and the location of the forest work machine or its boom in relation to the tree to be felled.

15. A forest work machine according to any one of claims 10-12, characterized in that the control system comprises at least one imaging means for imaging the tree to be felled and that the control system is configured to imagine the tree to be felled, determine based on the imaging at least one following piece of information describing the tree to be felled: centre of gravity of the tree or tilting direction of the tree, determine based on at least one piece of information describing the tree to be felled the natural falling direction of the tree, determine the natural falling direction of the tree as the primary felling direction of the tree, and control, when the primary felling direction implements the determined felling direction of the tree, the wood processing device to grab the tree to be felled in a position which controls the tree to fall into the primary felling direction, or control the wood processing device to grab the tree to be felled in a position which controls the tree to fall to one of at least one alternative felling directions.

16. A forest work machine according to any one of claims 10-15, characterized in thatthe control system comprises at least one imaging means to image at least partially the environment of the forest work machine in order to map trees located in the environment of the forest work machine, the display unit is configured to display based on imaging as a graphical presentation a tree map which shows the location of at least trees in the environment of the forest work machine in relation to the forest work machine, and that the display unit is configured to display graphically in the tree map at least one determined felling direction.

17. A forest work machine according to claim 16, characterized in that the display unit is configured to display the trees to be felled distin- guishably from the trees to be left standing and that the control system is configured to alternatively either warn about felling the tree into the felling direction shown in the tree map or prevent the felling of the tree into the felling direction shown in the tree map in a situation where the felling direction of the tree causes the tree to fall against a tree to be left standing.

18. A forest work machine according to any one of claims 15-17, characterized in that at least one imaging means comprises at least one of the following: a radar, a camera or a laser scanning device.

Images