The method relates to a method for controlling the functions of set of booms or of a tree-processing device attached to it, in connection with the event of felling a tree, in which method

- determining and/or estimating the attitude or state, relative to at least one degree of freedom, of the set of booms ,

- determining the momentary operating state of the tree-processing device,

- controlling the tree-processing device using first control means,

- controlling the set of booms using second control means .

The invention also relates to a corresponding arrangement and a forestry machine.

When using a tree-processing device to fell a tree, it is often difficult for an operator to see the functions of the harvester head and to time the movements, which the felling of the tree requires, using the set of booms comprising the tree-processing device. Such a situation is repeated, for example, when approaching a tree with a harvester head, when the operator must guide the harvester head to the tree with the aid of the set of booms, at the same time as the harvester head's stripping blades are closed to grip the tree. It is then easy for the operator to move the harvester head at too great a speed with the aid of the set of booms, so that the harvester head will strike the tree at too great a speed, possibly damaging the tree, the harvester head, the set of booms, or all of the aforementioned.

Another example of a problematic situation is the felling sawing of the tree, after which the operator moves the butt of the tree using the harvester head by moving the set of booms in the area in which the tree processing takes place. If in this situation the operator moves the harvester head using the set of booms at the same time as the felling event is taking place, the cutting device, for example, the cutting saw, may be damaged. The problem is thus that, due to poor visibility, the operator can easily damage the forestry machine or the tree trunk being felled, or both of them. Another related problem is that, in order to avoid damage, the operator can easily wait too long, for example, when felling cutting has ended, even when it would be safe to perform a movement of the booms. Thus time is wasted in unnecessary waiting and the work efficiency diminishes. The same felling-sawing work stages can be repeated 500 - 2000 times during a work shift, so that an additional waiting of, for example, a second in one work stage, can result in a loss of up to several tens of minutes of work time. Unnecessary long waiting to move the set of booms can also lead to a dangerous situation, because the felling of the tree is generally determined by moving the butt of the tree in the opposite direction to the felling direction.

An automated control system for the attitude of a tool sus- pended at the end of a set of booms is known from publication FI 123932 B. In this control system, the attitude of the tool, for example the attitude of a harvester head when approaching a tree, is also controlled at the same time with the aid of the control commands of the set of booms. A draw- back of such a system is that full automation demands extensive sensoring and the forestry machine can be damaged as a result of erroneous measurement by the sensoring. In addition, the sensoring increases not only the manufacturing costs and price of the machine but also the number of possible failure points in the machine, so that the probability of system disturbances and the need for maintenance increase too.

The invention is intended to create a simpler method and arrangement than solutions of the prior art for controlling the functions of a set of booms or a tree-processing device suspended from it in connection the felling of a tree. The char- acteristic features of the method according to the present invention are stated in the accompanying Claim 1 and the characteristic features of the arrangement in Claim 15. Further, the invention is intended to create a simpler forestry machine than solutions of the prior art, by which the felling sawing of a tree can be performed semi-automatically . The characteristic features of this invention are stated in the accompanying Claim 18.

The intention of the method according to the invention can be achieved by means of a method for controlling the functions of a set of booms or a tree-processing device suspended from it in connection with a felling event, in which method the attitude or state of the set of booms is determined and/or estimated relative to at least one degree of freedom, the mo- mentary operating state of the tree-processing device is determined, the tree-processing device is controlled using first control means and the set of booms is controlled using second control means. In the method, one of the set of booms and the tree-processing device is an operating unit and cor- respondingly the second is a control unit, in which method at least one pre-recorded function, which is bound to a first input created by the operator for the operating unit, is defined in a memory, preferably the memory of the control sys- tern of the forestry machine. In connection with the tree- felling event, the pre-recorded function of the operating unit is selected automatically from the memory on the basis of the first input created by the operator, and a second input, which contains a conditional criterion for initiating the selected pre-recorded function of the operating unit, is formed on the basis of the momentarily determined operating state of the control unit. In addition, the selected prerecorded function of the operating unit is initiated automatically when the criterion of the second input is met, and the selected pre-recorded function of the operating unit initiated by the second input is performed automatically.

By defining the function of the operating unit pre-recorded in the memory, the function in question can be performed au- tomatically, when the operating state of the control unit and the operator permit the performance of the function. Thus the tree-processing device, the set of booms, and the tree are protected by two safety features, i.e. by the automated operation of the operating unit, making it improbable that the operator will break the forestry machine. On the other hand, the forestry machine is protected by the initiation of the function of the operating unit performed by the operator, so that the automated function of the operating unit cannot initiate without supervision by the operator, in case of deviat- ing situations. This permits the forestry machine and system to be implemented in a simpler form, as the method can be implemented without the excessive monitoring and sensoring demanded by full automation. In this connection, the term operating unit refers to a first part selected from the tree-processing device and the set of booms, which automatically performs a pre-recorded function. The term control unit, for its part, refers to a second part of the tree-processing device and the set of booms, which is not the operating unit, on the basis of the operating state or attitude of which a preselected function can be initiated. The operation of the control unit is preferably manual, whereas the operation of the operating unit is automatic in the case of the pre-recorded function.

In this connection, the definition "in connection with the tree-felling event" refers to the functions of the tree- processing device up to the cutting of the tree into shorter parts, preferably up to the cutting event. In the cutting event, the butt of the tree is separated from the rest of the tree's trunk.

The method is preferably used in connection with forestry ma- chines intended for felling and processing trees. Forestry machines also handle very heavy trees, when the need for automation increases, as the forces acting on the set of booms and the tree-processing device increase and in turn also the risk of damage to the equipment through misuse.

The selected pre-recorded function of the operating unit initiated by the second input is preferably performed automatically relative to at least one degree of freedom of the defined and/or estimated attitude of the operating unit.

The degrees of freedom of the set of booms can be the movement of the set of booms, the direction of movement of the set of booms, the orientation of the set of booms, the reach of the set of booms, the mutual attitudes of booms of the set of booms, the loading of the set of booms, and the distance of the end of the set of booms from the base.

The tree-processing device is preferably a harvester head. In particular, the harvester head has several functions, which for their part can obstruct the operator from seeing what stage the harvester head is currently performing. The semiautomatic operation of the method according to the invention is therefore especially advantageous in connection with har- vester heads.

According to one embodiment at least two pre-recorded functions of the operating unit are defined in the memory. The operator can then select the function he wishes already dur- ing the operation of the control unit from several prerecorded functions of the operating unit, if the operating state of the control unit is such that there are alternatives for the next function of the operating unit. In the method, the pre-recorded function of the operating unit is defined in the memory before felling a tree. The operator can then select a pre-recorded function of the operating unit already before the criterion contained in the second input relating to the operating state of the control unit has been met, so that the pre-recorded function of the operating unit can initiate immediately when the criterion is met. This saves a considerable amount of time during even one work shift . In the method, a first input is formed preferably on the basis of one or more variables, which variables are: a control signal of the first control means, a control signal of the second control means, a determined property of the tree, the control unit's operating state determined at the moment. Though the determined property of the tree or the control unit's operating state determined at the moment are not events directly caused by the operator, but automatically performed measurements, the formation of the first input from them requires the operator's approval and through that his participation in the operation. For example, the determining of the property of the tree has required the operator to guide the tree-processing device for the processing of the tree, so that the tree's properties can be determined.

In the method according to a first embodiment of the invention, the tree-processing device is used as the control unit and the set of booms as the operating unit. The functions of the tree-processing device often guide the operation of the set of booms temporally and define the correct timing of the movements of the set of booms.

The operating state to be defined of the tree-processing device can be one or more of the following: the movement or at- titude of the stripping blades of the tree-processing device, the closing or opening movement or attitude of the feed rollers of the tree-processing device or the rotation of the feed rollers, the level or speed of change of the compressive force of the stripping blades or feed rollers, the attitude of the tree-processing device, the operation, preferably the rotation or operating state of the cutting device of the tree-processing device, the attitude or operating state of the cutting saw, the attitude of the cutting device, preferably the cutting saw of the tree-processing device, the height level of the tree-processing device relative to the base of the set of booms, and the attitude or operating state of the rotation device of the tree-processing device. The initiation of the pre-recorded function of the set of booms can depend on the functions referred to above, on the basis of which the criterion contained in the second input for initiating the operation of the set of booms is either met or not met. In this connection, the term "movement of the stripping blades" can refer to the state of the stripping blades when moving.

The function of the set of booms can be a change in the path of movement of the set of booms and/or a change in the attitude of the set of booms relative to at least one degree of freedom and/or an increase in or removal of the loading of the set of booms relative to at least one degree of freedom or the tensile force caused in the tree by the tree- processing device by loading the other operating device belonging to the set of booms without moving the set of booms or the locking or floating of the other operating devices of the set of booms, i.e. release of the movement of the other operating devices of the set of booms. All of these functions are such that if carelessly performed or carried out at the wrong time by the operator could damage the forestry machine. In addition, the function of the set of booms can be a change in the path of movement by a control signal formed by the operator or a first input formed by the operator.

The criterion contained in the second input is preferably a change in the operating state of the tree-processing device. The term operating state refers either to a function being implemented in the tree-processing device, such as, for example, felling sawing or similar, or a break between functions. For example the termination of felling sawing can be one such change in the operating state, which acts as a criterion for initiating the pre-recorded function of the set of booms. I.e., when felling sawing terminates, the function of the set of booms can be initiated, if the operator has approved this with the aid of the first input. According to a preferred embodiment, the second input is the rotation of the cutting saw (saw chain) of the tree- processing device, or the attitude of the flange of the cutting saw or its progress relative to the diameter of the butt of the tree being felled, the criterion is the termination of felling sawing and the function of the set of booms is the raising of the set of booms and its folding towards the base of the set of booms. In this connection, the term raising the set of booms preferably refers to the upwards movement of the lifting cylinder of the set of booms, whereas the term folding of the set of booms refers to the movement of the folding cylinder that moves the end of the booms towards the base. In addition, the function of the set of booms can preferably also comprise the lateral movement of the set of booms when the set of booms folds, when the end of the set of booms also moves partly laterally relative to the base of the set of booms .

According to another embodiment, the set of booms is used as the control unit and the tree-processing device as the operating unit .

The function of the tree-processing device can be the movement of the feed rollers performed by the tree-processing de- vice, the first input can be the moving of the set of booms towards the tree parallel to it, and the second input can be a change in the attitude of the feed rollers. In such a case, the automatic control of the tree-processing device according to a pre-recorded function is advantageous.

The cutting device used in the method of the tree-processing device is preferably a chain saw, but it can also be a guillotine cutter, a knife cutter, a circular saw, or some other cutting device suitable for cutting a tree. In the system according to the invention, a pre-recorded first input is preferably also stored in the memory, using which the operator can interrupt the pre-recorded function of the set of booms in the middle of implementing the function. Thus the operator can at any point whatever interrupt a function implemented by the semi-automation, if something particular happens and the environment and/or the forestry machine is endangered. Thus the risk caused by fully automated func- tions is avoided, as the operator can initiate and interrupt the operation of the automation.

In the method according to the invention, the pre-recorded functions can be automatic paths of movement /functions of the operating unit, which the operator, according to the prior art, would make manually simultaneously with the operation of the control unit. In the method according to the invention, the paths of movement of the operating unit are not restricted, instead they are automated.

The pre-selected function of the operating unit is preferably performed simultaneously with the function of the control unit performed by the operator. Often the processing and felling of a tree demands the simultaneous use of both the tree-processing device and the set of booms. In the method according to the invention, the function of the operating unit can be performed automatically, so that the operator can concentrate on performing the function of the control unit manually .

The intention of the arrangement according to the invention can be achieved using an arrangement for controlling a forestry machine in connection with a tree-felling event, in which the forestry machine includes at least a two-part set of booms, preferably comprising a main boom and a pivoted boom, a tree-processing device for felling trees attached to the set of booms, first operating devices located in the tree-processing device for realizing the functions of the tree-processing device, and second operating devices located in connection with the set of booms for realizing the functions of the set of booms. In addition to this, the forestry machine includes first control means for controlling first operating devices manually and second control means for con- trolling second operating devices manually for operating the set of booms and the tree-processing device, as well as first determining means for measuring and/or for estimating the operating state of the tree-processing device, arranged to produce a first determination result and second determining means for measuring or determining and/or for estimating the attitude of the set of booms relative to at least one degree of freedom, arranged to produce a second determination result. In addition, the forestry machine includes a control system for using the control signals formed by the first con- trol means and the second control means for controlling the first operating devices and the second operating devices. The arrangement includes a memory connected to the control system and software means arranged with the memory for controlling the first operating devices and the second operating devices at least partly automatically. In the arrangement, one of the set of booms and the tree-processing devices is an operating unit and the other a control unit. The software means are arranged to define in the memory at least one pre-recorded function of the operating unit, which is bound to a first in- put for the operating unit, and, in connection with the tree- felling event, to select the pre-recorded function of the operating unit automatically from the memory on the basis of a first input created by the operator. In addition, the software means are arranged to form a second input of the basis of the operating state of the control unit at the moment, which includes a conditional criterion for initiating the selected pre-recorded function of the operating unit, to initiate automatically the selected pre-recorded function of the operating unit when the conditional criterion of the second input is met, and to perform the pre-recorded selected function of the operating unit, initiated by the second input, automatically . In the arrangement according to the invention, pre-recorded functions of the operating unit can be performed with the aid of the software means, once the operator has selected them with the aid of the first input and the operating state of the operating unit has changed in such a way that it is safe to perform the function of the operating unit. This permits the arrangement to be manufactured in a considerably lighter form than fully automated arrangements, in which significantly extensive sensoring is required in order to detect possible fault states of the sensoring or to make the necessary definitions of attitude or operating state.

The tree-processing device is preferably a harvester head, which includes an inertia-measuring unit for determining the state of movement of the harvester head and indirectly also of the tree being felled. With the aid of the inertia- measuring unit the state of movement of the harvester head and indirectly also of the tree being felled can be determined precisely and the movements of the set of booms can be automated on its basis to optimize the end result.

The software means are preferably arranged to perform the selected pre-recorded function initiated by the second input automatically on the basis of the degree of freedom defined and/or estimated by the operating unit. The intention of the forestry machine according to the invention can be achieved by means of a forestry machine, which includes an arrangement according to the aforesaid embodi- ment .

By means of the method, arrangement, and forestry machine according to the invention, the advantage is achieved that it is possible to facilitate the control of the manual movements of demanding work stages, as the software means time the movements of the operating unit automatically according to the (completing) of the work stages of the control unit and prevent damaging functions before the completion of the previous work stage. Using the invention also prevents the breaking of the forestry machine, as functions are prevented that could damage the forestry machine in the wrong work stage or operating state. As an additional advantage, the invention permits efficient working in poor visibility, when the feeling event cannot be seen by the operator due to, for example, night, snow, distance, or the operator's vision. As another additional advantage the invention permits working without worries at greater distances, when the efficiency of working improves, as the need to move the forestry machine is reduced and the working speed increases. The safety of the felling event and the precision of the felling direction also improve, because the movement of the tree butt is commenced as far as possible at the right time.

In the following, the invention is described in detail with reference to the accompanying drawings showing some embodiments of the invention, in which Figure 1 shows the forestry machine according to the invention and the arrangement in it as an axo- nometric schematic diagram,

Figure 2 shows the stages of the method according to the invention as block diagrams,

Figure 3 shows a side view of one harvester head when it is the tree-processing device of the forestry machine,

Figure 4a shows the tree-felling event axonometrically, when the harvester head has gripped the tree,

Figure 4b shows the tree-felling event axonometrically, when the has been felled and turned to the stripping attitude with the aid of the set of booms and the harvester head,

Figure 5 shows the stages of a second embodiment of the method according to the invention as block diagrams .

Figure 1 shows the arrangement 10 and forestry machine 100 according to the invention. The arrangement 10 according to the invention is preferably part of a forestry machine 100, i.e. the forestry machine 100 is equipped with the arrangement 10 according to the invention already during manufacture. Alternatively, the arrangement 10 can be arranged in already existing forestry machines, in which there are the other components required by the arrangement.

In the main embodiment of the invention shown in Figures 1 - 4b, the set of booms acts as the operating unit and the tree- processing device as the control unit and the operation and characteristics of the invention are described in relation to this embodiment. In this connection, the term main embodiment refers to the choice of the set of booms and tree-processing device as the operating unit and control unit. The arrangement 10 can be applied to a forestry machine 100, such as, for example, a forestry machine equipped with wheels or a crawler chassis, which includes at least a set of booms 12 and a tree-processing device 14 together with operating devices 18 and 20, control means 22 and 24, and determining means 26 and 28. Preferably, the set of booms is a structure consisting of at least two booms pivoted to each other, i.e. a main boom 12.1 and a pivot boom 12.2, pivoted to the frame of the forestry machine 100, to which is attached a tree- processing device 14 for felling trees 16. The pivot booms of the set of booms preferably comprises an extendable extension, a so-called telescopic extension, to increase the reach of the set of booms. The tree-processing device 14 is prefer- ably the harvester head 14' shown in Figures 1 and 3, which is either suspended from or otherwise attached to the set of booms 12. Hereinafter, when describing the embodiments, a harvester head will be used as an example of the tree- processing device, but it should be understood that, instead of a harvester head, the tree-processing device can also be an energy grab or other tool used in the felling event.

To perform the functions of the harvester head 14', the forestry machine 100 includes the first operating device 18 of the harvester head 14', which can be, for example, hydraulic cylinders or motors, which drive, for example, the rotation device 50 of the harvester head 14' of Figure 3, the cutting saw 60, the stripping blades 52 and 56, the feed rollers 54 and 58, and the opening and closing mechanism 55 of the feed rollers 54 and 58. Correspondingly, to perform the functions of the set of booms 12, in connection with the set of booms 12 there are second operating devices 20, which are, for example, hydraulic cylinders 20' pivoted between the various parts of the set of booms 12. The first control means 22 control the first operating devices 18 and through them the operation of the harvester head 14' manually at least when the operator himself is control- ling the harvester head 14'. The second control means 24 in turn control the operation of the second operating devices 20 for operating the set of booms manually at least when the operator himself is controlling the set of booms. The first control means and the second control means can also be fitted to a single controller, which can be located in the forestry machine or in a remote-control point of the forestry machine with the aid of telecommunications links. More generally, the first control means and the second control means are joysticks, used by the operator, in the cab of the forestry ma- chine.

Because in the arrangement 10 and forestry machine 100 according to the invention it is sought to achieve semi- automation of the movements of the set of booms 12, it must be possible to monitor the functions of both the harvester head 14' and the set of booms 12 automatically. The first determining means 26 perform the measurement and/or estimation of the operating state of the harvester head 14', thus producing a first determination result. The determining means are preferably sensors, which measure the various functions of the harvester head 14', such as the rotation speed or attitude of the saw chain of the cutting saw, the attitude of the stripping blades, the attitude of the harvester head, and similar. An inertia-measuring unit (IMU) can also be used as a kind of sensor, on the basis of which the attitude and state of movement of the harvester head can be known precisely, but the attitude and state of movement of the tree can be known indirectly. Thus when the tree is sufficiently firmly in the grip of the harvester head (against the bottom and with a suitable support force of the cutting blade and feed rollers) length measurement of the tree will operate reliably. In addition to or in place of direct measurement, the operating states of the harvester head can also be guessed, i.e. estimated on the basis of previous determination results determined from the harvester head. This can mean, for example, that, on the basis of a change in the rotation speed of the cutting saw or a change in the speed of movement of the cutting flange or a change in the flow or pressure of the pressure medium, the time of the termination of the felling sawing can be estimated.

In connection with the set of booms 12, the attitude or state of the set of booms 12 can be measured and/or estimated with the aid of the second determining means 28 relative to at least one degree of freedom, in order to produce a second determination result. Preferably, the second determining means too are sensors 46, with the aid of which, for example, the momentary location or attitude of the set of booms is deter- mined. In addition to or in place of this, the location, path of movement, or internal stresses in the set of booms, which can be created with the aid of the operating devices, can also be estimated. In addition, it should be noted that the forces acting on the tree being felled by the harvester head can also be determined.

In the forestry machine, the control signals formed by the first control means 22 and the second control means 24 are converted with the aid of the control system 30 into commands to the valves regulating the movements of the operating devices 18 and 20. The control system 30 can be, for example, the central computer of the forestry machine 100, which by using a CAN bus or similar data-transfer bus transfers the control commands between the valves controlling the control means, determining means, and operating devices.

In the arrangement 10 according to the invention, the ar- rangement 10 itself includes a memory 32 connected to the control system 30 and software means 34 arranged in the memory 32. The software means preferably act between the control system, the control means, the determining means, and the operating devices, thus permitting the operator to per- form semi-automation in addition to manual commands. The software means are preferably some software or computer program or computer-program product, which operates on top of the control system. According to one embodiment, the software means can also be located at the end of a remote connection, so that data of the control system of the forestry machine are sent to the software means at another location using the remote connection. In the arrangement 10, at least one prerecorded function of the set of booms 12, which is bound to a first input 36 for the set of booms, is defined in the memory 32 with the aid of the software means 34. This means that, for example, the operator can, through the graphical user interface of the control system 30 pre-define in the memory 32 a path of movement of the set of booms, which he wishes to realize during, after, or before some function of the har- vester head. Alternatively, this pre-recorded function of the set of booms can be recorded in the memory 32 already at the factory. A situation can be used as an example in which, after felling sawing of the harvester head a lift and a move of the tree to the processing location is made by the set of booms .

In this connection, the term pre-recording means that one or more control signals to the valves controlling the second operating devices of the set of booms are recorded in the memory. Preferably a series of several control signals relates to one pre-recorded function. In addition to the control signals, a second input and a conditional criterion it contains, by which the control signals can be implemented, are also defined to be monitored in the case of each prerecorded function of the set of booms. For example, if the pre-recorded function of the set of booms is the path of movement of the set of booms, the second input can be, for example, a change in the rotation speed of the saw chain of the cutting saw, when the conditional criterion for initiating the path of movement of the set of booms can be a sudden rise in the rotation speed of the saw chain, which indicates that sawing through has taken place. In addition, the second input for initiating the path of movement of the set of booms can be, for example, a drop in the rotation speed of the cutting saw below a limit value, or a change in the rotation speed by a limit value. Other alternatives can be the attitude, speed of movement, speed of movement relative to the rotation speed of the saw chain, and/or the pressure force or the speed of change in these of the saw flange.

In this case, the first input 36 for the set of booms is preferably, for example, a command of some second control means, to which the pre-recorded function of the set of booms is linked. I.e. the operator can, for example, by rotating the control means, such as, a joystick, select a pre-recorded function, if he decides not to perform the function in question manually. In other words, when the operator performs some command of the control means, the software means detect the command as being the same as the command for selection of the pre-recorded function of the set of booms.

When the first input 36 comes from the operator to the software means 34, the software means 34 are arranged to automat- ically select the pre-recorded function of the set of booms 12 from the memory 32 on the basis of the first input 36 created by the operator and to form a second input 38 on the basis of the operating state of the harvester head 14' at that moment, which contains a criterion, preferably conditional, for initiating a pre-recorded function of the set of booms 12. In other words, the software means 34 collect the determination results formed by the first determining means and, on their basis, form a second input 38, i.e. an initiation command to perform the pre-recorded function of the set of booms, when some criterion, such as, for example, the termination of the felling sawing, is met. Thus the pre-recorded function of the set of booms is not initiated before the criterion is met and it is safe to begin to perform functions of the set of booms without breaking the harvester head or damaging the environment. As a practical example, the sensor monitoring the position of the cutting saw of the harvester head notifies the control system of the position of the cutting saw. When the diameter of the tree is known on the basis of the data determined from the stripping blades and/or the feed rollers and at the same time the angle of rotation is monitored from the saw case of the saw flange of the cutting saw, it can be decided when the tree has been sawn through. The condition of the criterion is that the tree is sawn through and when it is met, the preselected function of the set of booms can be initiated.

Alternative criteria can be a change in the speed of rotation of the cutting saw, when the sawing through of the tree can be detected from the acceleration in the rotation speed of the saw. A second alternative criterion can be a change in the speed of rotation of the saw flange of the cutting saw, when cutting through can be detected from the acceleration in the speed of rotation of the saws flange. A third alternative is to monitor the pressure acting over the motor of the cutting saw, when a reduction in pressure tells of sawing through. A fourth alternative is to monitor the change in current, if the cutting-saw motor is electric. A fifth alter- native is to monitor the acceleration of the harvester head with the aid of an inertia-measuring unit, when a change in it can be interpreted as sawing through happening. In addition to this, the criterion can also be some other data obtained through the determining means.

Finally, the software means are arranged to perform the prerecorded function of the set of booms 12 initiated by the second input 38 automatically on the basis of the attitude of the set of booms 12 determined and/or estimated relative to at least one degree of freedom. In other words, the said software means 34 forward to the memory 32 the control signal or signals relating to the pre-recorded function of the set of booms from the control system 30 to the valves controlling the operating devices of the set of booms, in order to oper- ate the second operating devices.

The following describes the stages of the method according to the invention as stages 202 - 220 according to Figure 2. The method according to the invention relates to the control of the set of booms in connection with a tree-felling event, i.e. to events preceding the cutting sawing of the felled tree. It should be understood, that, though the stages 202 - 220 are shown as being consecutive in Figure 2, the stages 204 - 208 take place in practice simultaneously. According to stage 204, the operating state of the harvester head is determined and/or estimated continuously with the aid of first determining means, so that the control system and the operator have information on the state of the harvester head at the moment. The operating state of the harvester head can be an active state, in which the first operating devices perform a specific function in the harvester head, or a passive state, in which the harvester head awaits the operation of the set of booms. According to stage 206, at the same time the operating state of the set of booms is determined and/or estimated continuously with the aid of second determining means, so that the control system and the operator have information on the momentary operating state of the set of booms. The operating state of the set of booms can be an ac- tive state, in which the second operating devices perform a specific function of the set of booms, i.e. the path of movement or the tension in the set of booms, or a passive state, in which the set of booms awaits the operation of the harvester head or is locked. Stages 204 and 206 take place con- tinuously during all the method stages.

According to stage 208, in connection with the felling event the harvester head is controlled with the aid of first control means to perform the tree-felling event and to support the feed tree when moving the tree. Correspondingly, the operations of the set of booms are controlled with the aid of second control means to bring the harvester head to the tree and for the harvester head to support the tree to move it to the desired location for further processing. In addition to this, the set of booms can be used to stress the tree with the aid of the harvester head by pushing, pulling, and/or lifting the tree or removing the tension from the tree, if the harvester head is moved with the aid of the feed rollers along the trunk of the still unfelled tree. The control oper- ations of stage 208 preferably take place manually by the action of the operator, i.e. the operator controls the operation with the aid of the first control means and the second control means. The operator can, before the tree-felling event, during the tree-felling event, or after the tree-felling event, select some pre-recorded function of the set of booms according to phase 210, which he wishes to be performed automatically. The selection can take place, for example, using the second control means. The control signal of the second control means then acts as the first input 36 for the software means, when selected the pre-recorded function of the set of booms from the memory according to stage 211.

For the pre-recorded function of the set of booms to be able to be performed, a second input 38 is required in addition from the first determining means of the harvester head, which determine the operating state of the harvester head at the moment. This determining takes place continuously, as previously stated, when, in addition to the operating state a conditional criterion contained in the second input is required, which defines the permitted operating states of the harvester head or their sub-areas. The meeting of the crite- rion is monitored continuously when the first input reaches the software means according to stage 212. If the criterion is not met according to stage 214, the pre-recorded function of the set of booms cannot be initiated, but instead the software means continue the program cycle 220 of the examina- tion of the criterion, which repeats stages 206, 212 and 214, until the criterion is met. In other words, the determination result of the said first determining means is compared with the limit value or values of the criterion continuously and when the determination result is in the area permitted, i.e. in the area meeting the criterion the pre-recorded function of the set of booms can be permitted, i.e. the control signals can be forwarded according to stage 216. The prerecorded function of the set of booms can then be performed according to stage 218. The following is a description of the use of various embodiments of the method according to the invention, with the aid of Figures 3 - 4b. According to the first embodiment, the method according to the invention can be used in a stage of the felling of a tree before the tree is felled, or when approaching the tree and when gripping the tree. The prerecorded function of the set of booms is then the path of movement towards the tree of the set of booms taking place at a restricted speed as the stripping blades close around the tree. In this way the harvester head is prevented from being driven too fast onto the tree and the risk of breaking the stripping blades is reduced. The second embodiment takes place before the felling event of the tree 16, when the tree 16 has been gripped by the harvester head 14', the stripping blades of the harvester head 14' are closed, and also the feed rollers are closed on the tree according to Figure 4a. Then when running the harvester head to the butt of the tree or running the harvester head using the feed rollers upwards on the tree trunk, as the prerecorded function of the set of booms the set of booms is controlled or the set of booms is used to monitor the movement of the harvester head to reduce the stresses in the set of booms. In this way the stress in the set of booms is reduced, which arises when the harvester head is run onto the tree using the feed rollers and the position of the end of the set of booms changes while the pivots of the set of booms remain stationary.

According to the third embodiment, when the harvester head is gripping the tree, the harvester head is pushed in some direction by moving the set of booms in order to create the desired stress and preferably also the direction. The pre- stressing can be in three directions up, forward, of the side, or a combination of these. The pre-recorded function of the set of booms is then the movement of the set of booms in the desired direction in order to stress the tree trunk and/or the set of booms.

According to the fourth embodiment, the pushing of a large tree is permitted before felling, so that the tree is assisted to fall in the right direction and the risk is reduced of the tree falling in the wrong direction or in the direction of the forestry machine.

According to the fifth and particularly preferred embodiment, the pre-recorded function of the set of booms in connection with the felling event is the locking of the second operating devices. The second input is then the rotation speed of the cutting saw, which when it is greater than 0, the second operating devices of the set of booms are locked and the movement of the set of booms is prevented.

The pre-recorded function of the set of booms of the sixth embodiment is the path of movement of the set of booms, which can be implemented when the criterion of the second input is met. Here the criterion is the rotation speed of the cutting saw, which when it is zero the pre-recorded path of movement can be implemented. In other words, the movement of the set of booms is prevented when the cutting saw is cutting the tree. The said path of movement of the set of booms can be partly lifting (initially) and partly pulling towards the ma- chine or processing location or cutting-sawing location. The term cutting-sawing location refers to the place where the felled tree can be stripped and cut according to the cut-to- length logging method (CTL) . In Figure 4b, the set of booms 12 and the harvester head 14' have been run to the felling event, i.e. to the felling-event location. More precisely, the pre-recorded function of the set of booms, i.e. the path of movement of the set of booms in the direction of the forestry machine can be formed in in such a way that the desired shape of the path of movement is defined, i.e. rising rapidly and thereafter linear. The zero point of the path of movement can be bound to the felling location, when the path of movement between the zero point and the forestry machine or processing location can be defined to have the selected shape, it being particularly initially rising towards the transfer location, after which there is linear movement horizontally, or rising or falling at the selected angle. The profile of the path of movement can be determined by the operator, such as, for example, rising over a distance of 1 metre and other- wise at the same height.

The seventh embodiment is otherwise the same as the sixth, but when working on a slope attention is also paid to the height location of the forestry machine relative to the zero point. The first and second determining means should then determine the locations and the height differences of the locations of the harvester head and forestry machine.

According to the eighth embodiment, the method can be used to implement feed of the tree during felling. This means that when the tree has been sawn through and falls, the tree trunk in the harvester head is fed towards the cutting point, when the potential energy of the tree can be exploited and time saved. As the tree moves downward, it saves energy and fuel, as in the horizontal position (normal state) the feeding of the tree using the feed rollers consumes more energy. More specifically, the pre-recorded function of the set of booms is the path of movement, which is realized when the inertia- measuring unit of the harvester head or the second determining means of the boom tell that the tree has started to fall.

According to the second main embodiment, the tree-processing device acts as the operating unit and the set of booms as the control unit. When in the first main embodiment of the invention described in connection with Figures 1 - 4b the operation of the set of booms is controlled semi-automatically on the basis of the operating state of the tree-processing de- vice, in the second main embodiment it is possible to correspondingly control the operation of the tree-processing device semi-automatically on the basis of the operating state of the set of booms . The following describes examples of the second main embodiment of the invention, in which the tree-processing device acts as the operating unit and the set of booms as the control unit. An example of such a situation is when the harvester head acting as the tree-processing device is used to grip the tree at a height of about 2 metres in a situation in which it is intended and necessary to run the harvester head at the butt (roots) of the tree in the trunk of the tree. This running needs the movement of the set of booms to follow the changing attachment point and the rotation (i.e. feed) of the feed rollers of the harvester head to run the harvester head to the butt of the tree.

Figure 5 shows a simple block diagram of the implementation of the second main embodiment according to the invention. Generally in the method the tree-felling event begins according to stage 302 and initially the state or attitude of the harvester head is determined or estimated according to stage 304. This can mean, for example, determining the attitude of the striping grabs, on the basis of which contact with the tree is decided. At the same time, the function of the set of booms is also determined according to stage 306, which can be, for example, simply is the set of booms moving on not. The operator controls the harvester head using the first con- trol means and the set of booms using the second control means according to stage 308, for example, to bring the harvester head into contact with the tree to be felled by moving the set of booms towards the tree. Once the operator has guided the harvester head into contact with the tree and the harvester head detects contact with the tree, the operator gives the first input, i.e. begins to move the set of booms according to stage 310. On the basis of a previously defined state or attitude of the harvester head, such as, for example, that the stripping grabs are closed, the operator can then select the pre-recorded function of the harvester head from the memory according to stage 311. In this case, the function can be, for example, running the feed rollers automatically to follow the set of booms. Before initiating the preselected function, the automation checks the meeting of the second input according to state 312. The criterion of the second input can be, for example, the direction of movement of the set of booms parallel to the tree or the attitude of the stripping blades, from which the diameter of the tree is determined. Trees with a sufficiently large diameter are so large that the feed devices of the harvester head may not necessarily be able to move the tree, instead the transfer must be performed with the aid of the set of booms. When the second criterion is met the control system permits the prerecorded function to be performed according to stage 316 and then performs the rotation of the feed rollers and runs the feed rollers along the tree trunk automatically monitoring the movement of the set of booms according to stage 318. Preferably the control system matches the speed of the feed with the speed of movement of the end of the set of booms downwards, when it can minimize or prevent stress from arising in the set of booms and the harvester head. The control system is preferably able to run the set of booms to arrange its attitude in such a way that the end of the set of booms follows the direction of the tree trunk, as the end of the set of booms is directed essentially downwards in the case of only one part of the set of booms (i.e. the driver uses only one controller) . A second example of the implementation of a second main embodiment of the invention is a situation, in which the tree has been felled and is horizontal. It is particularly advantageous to use the invention in a situation in which the tree is especially large and the power of the set of booms, the forestry machine, or the harvester head is insufficient to process the tree in a normal manner. If it is desired to follow the tree using a crane, the movement of the set of booms and the feed of the harvester head must be synchronized and parallel to the tree trunk. The operator then guides the set of booms, so that the feed of the harvester head runs automatically along the tree trunk following the movement of the set of booms. In this way, the feed and functions of the harvester head are made to react (for example, to stop) more quickly than the movement of the set of booms. If the move- ment of the set of booms stops suddenly, the harvester head feed also stops rapidly.

What is advantageous in connecting the functions of the set of booms and the harvester head together according to the in- vention is that the movement is synchronized according to the slower part. I.e., because the set of booms often moves more slowly that the harvester head feed, it is then preferable to make the harvester head follow the functions of the boom. The harvester head is then the operating unit and the set of booms the control unit.

The embodiments of the invention do not depend on the pres- ence of the operator. In other words they can operate in a fully autonomic, automatic, or remotely controlled machine. The implementation of the invention requires knowledge of the attitude and state of movement of the set of booms, i.e. sen- soring relative to the attitude and state of movement (accel- eration) , and of the operating state of the harvester head.