EP-4739092-A1 - METHOD FOR PROCESSING WOOD IN WOOD PROCESSING DEVICE OF FOREST WORK MACHINE AND CONTROL SYSTEM FOR CONTROLLING OPERATION OF WOOD PROCESSING DEVICE

EP4739092A1EP 4739092 A1EP4739092 A1EP 4739092A1EP-4739092-A1

Abstract

A method for processing a tree (17) in a wood processing device (20) of a forest work machine (1), which comprises movable feeding means (22) pressable against the tree trunk for feeding the tree (17) in the wood processing device (20) and movable delimbing means (24a, 24b) pressable against the tree trunk for removing branches from the tree trunk. The tree (17) is fed in the wood processing device (20) by said feeding means (22) and, during the feed of the tree (17), branches are removed from the tree trunk by said delimbing means (24a, 24b) at the same time as the tree (17) is supported in the wood processing device (20) by said feeding means (22) and/or delimbing means (24a, 24b). In the method, a substantially vertical support force (FS) required for supporting the tree (17) in the wood processing device (20) is determined and at least one of following for producing said substantially vertical support force (FS) is adjusted: pressing force (PF22) of the feeding means (22) against the tree trunk or pressing force (PF24) of the delimbing means (24a, 24b) against the tree trunk. Furthermore, a control system (30) for controlling the operation of a wood processing device (20) of a forest work machine (1).

Inventors

HEIKKILÄ, Taneli
HALONEN, Marko
HAVIMÄKI, Esko
KIVI, Aleksi
OINONEN, Mikko
KOHIO, TONI
HOTTI, EERO
SAVOLAINEN, MARKKU

Assignees

Ponsse Oyj

Dates

Publication Date: 20260513
Application Date: 20240705

Claims (14)

1. A method for processing a tree (17) in a wood processing device (20) of a forest work machine (1), which comprises movable feeding means (22) pressable against the tree trunk for feeding the tree (17) in the wood processing device (20) and movable delimbing means (24) pressable against the tree trunk for removing branches from the tree trunk, and in which method feeding the tree (17) in the wood processing device (20) by said feeding means (22), removing branches from the trunk of the tree by said delimbing means (24a, 24b) during the feeding of the tree (17) and supporting the tree (17) in the wood processing device (20) by said feeding means (22) and/or delimbing means (24a, 24b), characterized by determining a detail describing a mass (M17) ofthe tree (17) or its part, determining, based on the detail describing the mass (M17) of the tree (17) or its part, a substantially vertical load (LD) applying to at least one of the following: the wood processing device (20), the feeding means (22) or the delimbing means (24a, 24b), determining a substantially vertical support force (FS) required for supporting the tree (17) in the wood processing device (20) based on at least one determined substantially vertical load (LD) and adjusting at least one of following when processing the tree (17) in wood processing device (20) for producing said substantially vertical support force (FS): pressing force (PF22) of the feeding means (22) against the tree trunk or pressing force (PF24) of the delimbing means (24a, 24b) against the tree trunk.
2. A method according to claim 1, characterized by determining a position (PO20) and state of motion of the wood processing device (20) and determining, in addition to a detail describing the mass (M17) of the tree (17) or its part, based on the position (PO20) and state of motion of the wood processing device (20), a substantially vertical load (LD) applying to at least one of the following: the wood processing device (20), the feeding means (22) or the delimbing means (24a, 24b).
3. A method according to claim 1 or 2, characterized by, when processing the tree (17) in the wood processing device (20), for determining a detail describing the mass (M17) of the tree (17) or its part, measuring a diameter (17) and a length (L17) of the trunk of the tree, determining, based on the measured diameter (D17) and the length (L 17 ) of the tree trunk related to the measurement of the diameter (D17), at least one of the following details: a volume detail (VI) of the part of the tree trunk the diameter (D17) of which was measured, or a volume estimate (VE) of the part of the tree trunk where the diameter (D17) of the tree trunk has not been measured, and determining a detail describing the mass (M17) of the tree (17) or its part based on a specific weight (TSW) of the tree species of the tree (17) and at least one of the following details: a volume detail (VI) of the part of the tree trunk the diameter (D17) of which was measured, or a volume estimate (VE) of the part of the tree trunk where the diameter (D17) of the tree trunk has not been measured.
4. A method according to claim 3, characterised by the wood processing device (20) comprising a cross-cutting device (25) and by determining a mass estimate (ME17) for the part of the tree trunk where the diameter (D17) of the tree trunk has not been measured based on at least one of the following details: said volume detail (VI) or said volume estimate [VE), determining based on the mass estimate (ME 17) a substantially vertical load (LD) applied to the wood processing device (20) by the part of the tree corresponding the mass estimate (ME17), determining based on the substantially vertical load (LD) applied to the wood processing device (20) by the part of the tree corresponding to the mass estimate (ME17) a substantially vertical support force (FS) required for supporting the part of the tree corresponding to the mass estimate (ME 17) in the wood processing device (20), cutting of the tree (17) the part of the tree unrelated to said mass estimate (ME17), and adjusting at least one of following for producing the substantially vertical support force (FS) corresponding to the mass estimate (ME17): pressing force (PF22) of the feeding means (22) against the tree trunk or pressing force (PF24) of the delimbing means (24a, 24b) against the tree trunk.
5. A method according to claim 1 or 2, characterized by, when determining a detail describing the mass (M17) of the tree (17) or its part to be processed in the wood processing device (20), imaging the tree (17) or its part before felling said tree (17) and determining a mass estimate (ME17) describing the mass (M17) of the tree (17) or its part based on the specific weight of the tree species (TSW) of the tree (17) and the imaging of the tree (17) or its part.
6. A method according to claim 5, characterized by imaging the tree (17) or its part in a way that is at least one of the following: by photographing the tree (17) or its part, by video photographing the tree (17) or its part or by laser scanning the tree (17) or its part.
7. A method according to any one of the previous claims, characterized by the wood processing device (20) comprises a cross-cut device (25) and, as a response to the cutting off the part of the tree trunk from the tree (17) being processed in the wood processing device (20), dropping stepwise the substantially vertical support force (FS) required for supporting the tree (17) in the wood processing device (20) by adjusting at least one of the following: pressing force (PF22) of the feeding means (22) against the tree trunk or pressing force (PF24) of the delimbing means (24a, 24b) against the tree trunk, feeding the tree (17) in the wood processing device (20) by said feeding means (22) and as the feed of the tree (17) in the wood processing device (20) proceeds, keeping said substantially vertical support force (FS) substantially constant or raising it by adjusting at least one of the following: pressing force (PF22) of the feeding means (22) against the tree trunk or pressing force of the delimbing means (24a, 24b) against the tree trunk.
8. A control system (30) for controlling the operation of a wood processing device (20) of a forest work machine (1), which wood processing device (20) comprises movable feeding means (22) pressable against the tree trunk for feeding the tree (17) in the wood processing device (20) and movable delimbing means (24a, 24b) pressable against the tree trunk for removing branches from the tree trunk, and which control system (30) is configured to control the feed of the tree (17) in the wood processing device (20) by said feeding means (22), the removing of branches from the trunk of the tree by said delimbing means (24a, 24b) during the feeding of the tree (17) and the supporting of the tree (17) in the wood processing device (20) by said feeding means (22) and/or delimbing means (24a, 24b), characterized in that the control system (30) comprises means for determining a detail describing a mass (M17) of the tree (17) or its part, and that the control system (30) is further configured to determine a detail describing a mass (M17) of the tree (17) or its part, to determine, based on the detail describing the mass (M17) of the tree (17) or its part, a substantially vertical load (LD) applying to at least one of the following: the wood processing device (20), the feeding means (22) or the delimbing means (24a, 24b), to determine a substantially vertical support force (FS) required for supporting the tree (17) in the wood processing device (20) based on at least one determined substantially vertical load (LD) and to adjust at least one of following when processing the tree (17) in wood processing device (20) for producing said substantially vertical support force (FS): pressing force (PF22) of the feeding means (22) against the tree trunk or pressing force (PF24) of the delimbing means (24a, 24b) against the tree trunk.
9. A control system according to claim 8, characterized in that the control system (30) comprises means for determining a position (PO20) and a state of motion of the wood processing device (20) and that the control system (30) is configured to determine, in addition to a detail describing the mass (M17) of the tree (17) or its part, a position (PO20) and a state of motion of the wood processing device (20) and to determine, in addition to a detail describing the mass (M17) of the tree (17) or its part, based on the position (PO20) and state of motion of the wood processing device (20), a substantially vertical load (LD) applying to at least one of the following: the wood processing device (20), the feeding means (22) or the delimbing means (24a, 24b).
10. A control system according to claim 8 or 9, characterized in that the control system (30) comprises means for measuring a diameter (D17) and a length (L17) of the tree trunk and that the control system (30) is configured to determine a detail describing the mass (M17) of the tree (17) or its part when the tree (17) is being processed in the wood processing device (20) by measuring a diameter (17) and a length (L17) of the trunk of the tree, determining, based on the measured diameter (D17) and the length (L17) of the tree trunk related to the measurement of the diameter (D17), at least one of the following details: a volume detail (VI) of the part of the tree trunk the diameter (D17) of which was measured, or a volume estimate (VE) of the part of the tree trunk where the diameter (D17) of the tree trunk has not been measured, and determining a detail describing the mass (M17) of the tree (17) or its part based on at least one of the following details: a volume detail (VI) of the part of the tree the diameter (D17) of which was measured, or a volume estimate (VE) of the part of the trunk of the tree where the diameter (D 17) of the trunk of the tree has not been measured.
11. A control system according to claim 10, characterized in that the wood processing device (20) comprises a cross-cut device (25) and that the control system (30) is configured to determine a mass estimate (ME17) for the part of the tree trunk where the diameter (D17) of the tree trunk has not been measured based on at least one of the following details: said volume detail (VI) or said volume estimate [VE), to determine based on the mass estimate (ME17) a substantially vertical load (LD) applied to the wood processing device (20) by the part of the tree corresponding to the mass estimate (ME17), to determine based on the substantially vertical load (LD) applied to the wood processing device (20) by the part of the tree corresponding to the mass estimate (ME17) a substantially vertical support force (FS) required for supporting the part of the tree corresponding to the mass estimate (ME 17) in the wood processing device (20), to control the cross-cutting device (25) to cut of the tree (17) the part of the tree not related to said mass estimate (ME17), and to adjust at least one of following for producing the substantially vertical support force (FS) corresponding to the mass estimate (ME17): pressing force (PF22) of the feeding means (22) against the tree trunk or pressing force (PF24) of the delimbing means (24a, 24b) against the tree trunk.
12. A control system according to claim 8 or 9, characterized in that the control system (30) comprises means for determining a detail describing the mass (M17) of the tree (17) or its part to be processed in the wood processing device (20) and that the control system (30) is configured to image the tree (17) or its part before felling said tree (17) and to determine a mass estimate (ME17) describing the mass (M17) of the tree (17) or its part based on the specific weight of the tree species (TSW) of the tree (17) and the imaging of the tree (17) or its part.
13. A control system according to claim 12, characterized in that the control system (30) comprises at least one of the following means for imaging the tree (17) or its part: a camera (41), a video camera (42) or a laser scanning device [43).
14. A control system according to any one of claims 8-13, characterized in that the wood processing device (20) comprises a cross-cutting device (25) and that, as a response to the cutting off of a part of the trunk of the tree (17) being processed in the wood processing device (20), the control system (30) is configured to drop stepwise the substantially vertical support force (FS) required for supporting the tree (17) in the wood processing device (20) by adjusting at least one of the following: pressing force (PF22) of the feeding means (22) against the tree trunk or pressing force (PF24) of the delimbing means (24a, 24b) against the tree trunk, to feed the tree (17) in the wood processing device (20) by said feeding means (22) and as the feed of the tree (17) in the wood processing device (20) proceeds, to keep said substantially vertical support force (FS) substantially constant or to raise it by adjusting at least one of the following: pressing force (PF22) of the feeding means (22) against the tree trunk or pressing force (PF24) of the delimbing means (24a, 24b) against the tree trunk.

Description

Method for processing wood in wood processing device of forest work machine and control system for controlling operation of wood processing device Background of the invention The invention relates to wood harvesting and particularly to a method for tree processing in a wood processing device of a forest work machine and a control system for controlling the operation of the wood processing device. When harvesting wood by a forest work machine, the wood is processed i.e. worked in the wood processing device of the forest work machine. Said wood processing typically comprises felling of a tree, removing branches from the felled tree i.e. delimbing, and cross-cutting the trunk of the felled tree into parts of preferred length. For delimbing the tree trunk, the felled tree is fed by means of feeding means pressable against the tree trunk in the wood processing device and, at the same time, delimbing means used for removing the branches are pressed against the tree trunk in the wood processing device. After this, such a section of the tree trunk of which branches have been removed or which had no branches originally is cross-cut into a part of preferred length. During delimbing, the tree being processed in the wood processing device is held up by said feeding means and said delimbing means at the same time as the tree being processed is fed by said feeding means forward in the wood processing device. If the pressing force of said delimbing means against the tree trunk is too low, the delimbing result is weak, that is, branch stubs or branch lumps remain on the surface of the tree trunk. Additionally, the support of the tree against the bottom of the wood processing device is weakened, whereby the tree may start to dangle in the wood processing device. Then, the height of the tree in the wood processing device changes and the measurement accuracy of the diameter of the tree is weakened. Furthermore, the delimbing means might cut inside the tree trunk or the tree may even totally fall off the wood processing device. Because the surface of the tree trunk slides along the frame of the wood processing device, a too high pressing force of said delimbing means against the tree trunk increases resistance for the feeding of the tree in the wood processing device, that is, the friction resisting the travel of the tree in the wood processing device increases. This again increases the power required for wood processing and the energy consumption. If the pressing force of said feeding means against the tree trunk is too low, the feeding of the tree in the wood processing device is weakened, which slows down wood processing and thus decreases productivity. If the pressing force of said feeding means against the tree trunk is in turn too high, unnecessarily much power is used for holding up, supporting and feeding the tree trunk, which unnecessarily increases energy consumption of wood processing. Additionally, said feeding means, particularly those implemented as feeding rolls, might damage the surface of the tree. According to a solution in use, the pressing force of the feeding means of the wood processing device against the tree trunk and the pressing force of the delimbing means against the tree trunk are controlled based on a measured diameter of the tree being processed. The measurement of the tree diameter is based on determining the aperture of said feeding means and/or delimbing means. In the solution in question, as the feeding of the tree proceeds, the pressing force is decreased when the diameter of the tree decreases. In order for the support of the tree to the wood processing device to be sufficient during the feeding of the tree, that is, also in the end stage of the feeding of the tree, the pressing force of the feeding means and delimbing means used for supporting the tree is often too high, which may cause above-mentioned disadvantages during the processing of the tree. Brief description of the invention The object of the invention is to provide a new type of a method for processing a tree in a wood processing device of a forest work machine and a new type of a control system for controlling the operation of the wood processing device of the forest work machine. The solution according to the invention is characterised by what is disclosed in the independent claims. The invention is based on the fact that, for processing the tree in the wood processing device of the forest work machine, a substantially vertical support force required for supporting the tree is determined and at least one of the following is adjusted for producing said substantially vertical support force when processing the tree in the wood processing device: a pressing force of feeding means against the tree trunk or a pressing force of delimbing means against the tree trunk. An advantage of the solution is that, when determining the substantially vertical support force required for supporting the tree in the wood processing device, the pre