An electric percussion device and a method for controlling the same

Abstract

An electric percussion device (100) comprises a frame (101), an actuator member (103) linearly movable with respect to the frame, and a linear electric machine (104) comprising a mover (105) for directing impacts to the actuator member and a stator (106) having windings for generating a magnetic force directed to the mover when electric currents are supplied to the windings. The electric percussion device comprises a power electronic converter (107) for driving the linear electric machine and a controller (108) for controlling the power electronic converter so that operation of the electric percussion device fulfills functionality defined by values of one or more operating parameters. The controller is configured to carry out an experiment run where the values of the one or more operating parameters are varied between temporally non-overlapping periods of percussion work and, after the experiment run, select most advantageous one or more values of the one or more operating parameters.

Description

[0001] An electric percussion device and a method for controlling the same

[0002] Field of the disclosure

[0003] The disclosure relates to an electric percussion device, such as an electric hammer device, that is connectable to an excavator or a to working machine of another kind. Furthermore, the disclosure relates to a method for controlling an electric percussion device. Furthermore, the disclosure relates to a computer program for controlling an electric percussion device.

[0004] Background

[0005] Typically, a percussion device is used as an attachment to an excavator or another working machine where the intention is to break up for example stone, concrete, or some other material. The percussion device can be attached e.g. to the boom of an excavator, in place of a bucket. The percussion device incorporates a mechanism configured to direct impacts to an actuator member, e.g. a chisel, whose end forms a tip which transmits the impacts to material to be broken up. At the same time as the impacts are directed to the actuator member, the percussion device is pushed against the material to be broken up. Thus, the above-mentioned tip penetrates, due to the impacts and the pushing, into the material to be broken up, and, consequently, breaks up the material.

[0006] The mechanism to direct impacts to the actuator member is typically hydraulic, but recently also electric mechanisms based on linear electric machines are becoming more common because hydraulic mechanisms have their own challenges. One of the challenges encountered with hydraulic percussion devices is their tendency to cause pressure shocks which can be destructive to the hydraulic system of a working machine. These pressure shocks can be smoothed, but to some extent only, by means of a pressure accumulator. Another challenge of a hydraulic percussion device is that it has a relatively high power consumption. The hydraulic system contains, in the energy flow direction, a plurality of energy-loss producing elements one after another, causing a reduction of the efficiency of the whole system. The energyloss producing elements include, for instance, an engine that drives a hydraulic pump, the hydraulic pump, and a piping and valve system that produces a flow resistance. Heating up of the hydraulic oil in the hydraulic percussion device may also pose its own challenges to the hydraulic system of the working machine.

[0007] On the other hand, an electric percussion device, such as a hammer or a rock drill, is not free from challenges either. One of the challenges is related to a control of a linear electric machine. For example, optimal or at least advantageous values of operating parameters determining functionality of an actuator member, e.g. a chisel, can be dependent on material, e.g. stone or concrete, under percussion work and / or on environmental conditions, e.g. temperature, of an operating environment of the electric percussion device. The operating parameters may determine for example a stroke frequency and / or impact energy of each stroke. Furthermore, the optimal or at least advantageous values of the operating parameters may depend on a way of working and / or working skills of an operator of the electric percussion device.

[0008] Summary

[0009] The following presents a simplified summary to provide a basic understanding of some aspects of various invention embodiments. The summary is not an extensive overview of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of exemplifying embodiments.

[0010] In this document, the word “geometric” when used as a prefix means a geometric concept that is not necessarily a part of any physical object. The geometric concept can be for example a geometric point, a straight or curved geometric line, a geometric plane, a non-planar geometric surface, a geometric space, or any other geometric entity that is zero, one, two, or three dimensional.

[0011] In accordance with the invention, there is provided a new electric percussion device, e.g. an electric hammer device, an electric rock drill device, or an electric impact hammer for piling.

[0012] An electric percussion device according to the invention comprises: a frame attachable to a working machine, the frame comprising attachment members configured to attach to the working machine so that the frame is nondestructively detachable from the working machine,

[0013] - an actuator member linearly movably supported with respect to the frame,

[0014] - a linear electric machine comprising a mover configured to direct impacts to the actuator member, and a stator attached to the frame and provided with windings configured to generate a magnetic force directed to the mover in response to one or more electric currents supplied to the windings,

[0015] - a power electronic converter configured to drive the linear electric machine by supplying the one or more electric currents to the windings, and

[0016] - a controller configured to control the power electronic converter to drive the linear electric machine so that operation of the electric percussion device fulfills functionality defined by one or more values of one or more operating parameters of the electric percussion device.

[0017] The controller is configured to:

[0018] - control the power electronic converter to carry out an experiment run, the experiment run comprising temporally non-overlapping periods of percussion work during which the actuator member hits material under the percussion work, the one or more operating parameters having, during each of the periods of the percussion work, one or more candidate values constituting a candidate value set related to the period of the percussion work,

[0019] - collect data related to the percussion work during each of the periods of the percussion work during which the candidate value set related to the period of the percussion work under consideration is used, and

[0020] - select, after the experiment run and based on the data collected during the periods of the percussion work, one of the candidate value sets to be a selected value set for percussion work after the experiment run. The one or more operating parameters may determine for example a stroke frequency and / or an impact energy of each stroke and / or maximum acceleration of the mover during an impact stroke of the mover when the mover moves towards the actuator member and / or average acceleration of the mover during an impact stroke of the mover.

[0021] In the experiment run, each candidate value set is advantageously used in many percussion work periods to mitigate an effect of stochastic variation between work performances carried out with different ones of the candidate value sets. For example, in stone breaking work, there can be stones of different sizes and possibly different stone materials and thus, to achieve a fair comparison between different candidate value sets, it is advantageous that work periods related to each candidate value set includes breaking of stones of different sizes and possibly different stone materials. Thus, in an electric percussion device according to an advantageous embodiment, the controller is configured to use each candidate value set in many of the periods of the percussion work to mitigate the effect of stochastic variation between work performances carried out with different ones of the candidate value sets.

[0022] The data collected during the periods of the percussion work in the experiment run may express for example temporal durations of the periods of the percussion work.. In this exemplifying case, the above-mentioned selected value set can be e.g. the candidate value set that corresponds to the smallest one of averages of the temporal durations, where each average corresponds to a respective one of the candidate value sets so that each average is an average of the temporal durations of those periods of the percussion work when the corresponding one of the candidate value sets was used.

[0023] For another example, the data collected during the periods of the percussion work in the experiment run may express energy consumptions of the electric percussion device during the periods of the percussion work. In this exemplifying case, the selected value set can be e.g. the candidate value set that corresponds to the smallest one of averages of the energy consumptions, where each average corresponds to a respective one of the candidate value sets so that each average is an average of the energy consumptions during those periods of the percussion work when the corresponding one of the candidate value sets was used.

[0024] In conjunction with this document, the word “set” is to be understood broadly so that a set may contain only one element, or more elements, i.e. it is not necessary that a set contains at least two elements.

[0025] In accordance with the invention, there is also provided a new method for controlling an electric percussion device that comprises:

[0026] - a frame attachable to a working machine, the frame comprising attachment members configured to attach to the working machine so that the frame is nondestructively detachable from the working machine,

[0027] - an actuator member linearly movably supported with respect to the frame,

[0028] - a linear electric machine comprising a mover configured to direct impacts to the actuator member, and a stator attached to the frame and provided with windings configured to generate a magnetic force directed to the mover in response to electric current supplied to the windings,

[0029] - a power electronic converter configured to drive the linear electric machine by supplying the electric current to the windings, and

[0030] - a controller configured to control the power electronic converter to drive the linear electric machine so that operation of the electric percussion device fulfills functionality defined by one or more values of one or more operating parameters of the electric percussion device.

[0031] The method according to the invention comprises:

[0032] - controlling the power electronic converter to carry out an experiment run, the experiment run comprising temporally non-overlapping periods of percussion work during which the actuator member hits material under the percussion work, the one or more operating parameters having, during each of the periods of the percussion work, one or more candidate values constituting a candidate value set related to the period of the percussion work, - collecting data related to the percussion work during each of the periods of the percussion work during which the candidate value set related to the period of the percussion work is used, and

[0033] - selecting, after the experiment run and based on the data collected during the periods of the percussion work, one of the candidate value sets to be a selected value set for percussion work after the experiment run.

[0034] In accordance with the invention, there is also provided a new computer program for controlling an electric percussion device. A computer program according to the invention comprises computer executable instructions for controlling a programmable controller of an electric percussion device to:

[0035] - control a power electronic converter of the electric percussion device to carry out an experiment run comprising temporally non-overlapping periods of percussion work during which the actuator member hits material under the percussion work, the one or more operating parameters having, during each of the periods of the percussion work, one or more candidate values constituting a candidate value set related to the period of the percussion work,

[0036] - collect data related to the percussion work during each of the periods of the percussion work during which the candidate value set related to the period of the percussion work is used, and

[0037] - select, after the experiment run and based on the data collected during the periods of the percussion work, one of the candidate value sets to be a selected value set for percussion work after the experiment run.

[0038] In accordance with the invention, there is also provided a new computer program product. The computer program product comprises a non-volatile computer readable medium, e.g. a compact disc “CD”, encoded with a computer program according to the invention.

[0039] Exemplifying and non-limiting embodiments are described in accompanied dependent claims. Various exemplifying and non-limiting embodiments both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying and nonlimiting embodiments when read in conjunction with the accompanying drawings.

[0040] The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require an existence of un-recited features.

[0041] The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated.

[0042] Furthermore, it is to be understood that the use of “a” or “an”, i.e. a singular form, throughout this document does not exclude a plurality.

[0043] Brief description of the drawings

[0044] Exemplifying and non-limiting embodiments and their advantages are explained in greater detail below in the sense of examples and with reference to the accompanying drawings, in which: figures 1 a and 1 b illustrate an electric percussion device according to an exemplifying and non-limiting embodiment, and figure 2 shows a flowchart of a method according to an exemplifying and non-limiting embodiment for controlling an electric percussion device.

[0045] Description of exemplifying and non-limiting embodiments

[0046] The invention and the embodiments thereof are not limited to the exemplifying and non-limiting embodiments described below. Thus, the specific examples provided in the description given below should not be construed as limiting the scope and / or the applicability of the appended claims. Lists and groups of examples provided in the description given below are not exhaustive unless otherwise explicitly stated.

[0047] Figure 1a shows an electric percussion device 100 according to an exemplifying and non-limiting embodiment. Figure 1 b shows section view taken along a line A-A shown in Figure 1 a. The geometric section plane is parallel with the yz-plane of a coordinate system 199. The electric percussion device 100 comprises a frame 101 attachable to a working machine, e.g. such as to the boom of an excavator in place of a bucket. The frame 101 comprises attachment members 102 for attaching to the working machine so that the frame 101 is nondestructively detachable from the working machine. The electric percussion device 100 comprises an actuator member 103, e.g. a chisel, linearly movably supported with respect to the frame 101. In this exemplifying case, an end of the actuator member 103 is shaped to constitute a tip for breaking material e.g. stone or concrete. It is also possible that the end of the actuator member is flat or round.

[0048] As illustrated in figure 1 b, the electric percussion device 100 comprises a linear electric machine 104 having a mover 105 and a stator 106. The stator 106 is attached to the frame 101 and provided with windings configured to generate a magnetic force directed to the mover 105 in response to electric currents supplied to the windings. The mover 105 is configured to direct impacts to the actuator member 103 in the negative z-direction of the coordinate system 199. The windings of the stator 106 may constitute for example a multi-phase winding, e.g. a two- or three-phase winding. In the exemplifying electric percussion device 100 illustrated in figures 1 a and 1 b, the linear electric machine 104 is a tubular linear electric machine in which conductor coils of the windings are configured to surround the mover 105. Figure 1 b shows cross-sectional views of the conductor coils of the windings. In figure 1 b, the cross-sections of the conductor coils are depicted by black rectangular patterns. The mover 105 can be, for example, substantially rotationally symmetric with respect to a geometric line parallel with the z-axis of the coordinate system 199.

[0049] The electric percussion device 100 comprises a power electronic converter 107 configured to drive the linear electric machine 104 by supplying electric currents to the windings of the linear electric machine 104. In the exemplifying case shown in figures 1 a and 1 b, the power electronic converter 107 is an inverter that is connected to a three-phase electric grid via an active rectifier. The electric percussion device 100 comprises a controller 108 configured to control the linear electric machine 104 by controlling controllable power electronic switches of the power electronic converter 107. In this exemplifying case the controllable power electronic switches are insulated gate bipolar transistors “IGBT”, but it is also possible that the controllable power electronic switches are gate-off thyristors “GTO” or some other suitable elements that can be switched on and off.

[0050] The controller 108 is configured to control the power electronic converter to drive the linear electric machine 104 so that operation of the electric percussion device 100 fulfills functionality defined by one or more values of one or more operating parameters of the electric percussion device 100. The one or more operating parameters may determine for example a stroke frequency and / or an impact energy of each stroke and / or maximum acceleration of the mover 105 during an impact stroke of the mover when the mover moves towards the actuator member and / or average acceleration of the mover 105 during an impact stroke of the mover. For example, when one of the operating parameters is the impact energy and the value of this operating parameter is E e.g. in joules, the controller 108 is configured to control the power electronic converter 107 to drive the linear electric machine 104 so that the speed v of the mover 105 is substantially (2E / m)1 / 2when the mover 105 hits the actuator member 103, where m is the mass of the mover 105. Suitable control sequences, which may depend on the position of the mover, for the controllable power electronic switches of the power electronic converter 107 can be for example tabulated and stored in a memory for achieving operation that fulfills functionality defined by one or more preselected values of the one or more operating parameters. The invention is however not limited to any specific ways to control the power electronic converter 107 to drive the linear electric machine 104 so that operation of the electric percussion device 100 fulfills functionality defined by the one or more values of one or more operating parameters.

[0051] The controller 108 is configured to control the power electronic converter 107 to carry out an experiment run that comprises temporally non-overlapping periods of percussion work during which the actuator member 103 hits material under the percussion work. The one or more operating parameters has / have, during each of the periods of the percussion work, one or more candidate values constituting a candidate value set related to the period of the percussion work. Each period of percussion work can be for example a period during which the linear electric machine 104 is running without pauses. During each period of percussion work in the experiment run, the candidate value or values of the one or more operating parameters is / are kept constant and data concerning the percussion work is collected by the controller 108, and the candidate value or values of the one or more operating parameters is / are varied between at least some of the periods of the percussion work. Thus, the controller 108 is configured to control the power electronic converter 107 to carry out the experiment run so that different candidate value sets each having one or more candidate values for the one or more operating parameters are used in the periods of the percussion work. The controller 108 is configured to select, after the experiment run and based on the data collected during the periods of the percussion work, one of the candidate value sets to be a selected value set for percussion work after the experiment run. Each candidate value set is advantageously used in many percussion work periods to mitigate an effect of stochastic variation between work performances carried out with different ones of the candidate value sets. For example, in stone breaking work, there can be stones of different sizes and possibly different stone materials and thus, to achieve a fair comparison between the candidate value sets, it is advantageous that work periods related to each candidate value set includes breaking of stones of different sizes and possibly different stone materials.

[0052] In an electric percussion device according to an exemplifying and non-limiting embodiment, the data collected during the periods of the percussion work in the experiment run expresses temporal durations of the periods of the percussion work and the controller 108 is configured to compute, for each of the candidate value sets, an average temporal duration of those periods of the percussion work during which the candidate value set under consideration was used, and thereafter to select one of the candidate value sets based on the average temporal durations so that the selected value set corresponds to the smallest one of the average temporal durations.

[0053] In an electric percussion device according to an exemplifying and non-limiting embodiment, the data collected during the periods of the percussion work in the experiment run expresses energy consumptions of the electric percussion device during the periods of the percussion work and the controller 108 is configured to compute, for each of the candidate value sets, an average energy consumption during those periods of the percussion work during which the candidate value set under consideration was used, and thereafter to select one of the candidate value sets based on the average energy consumptions so that the selected value set corresponds to the smallest one of the average energy consumptions.

[0054] In an electric percussion device according to an exemplifying and non-limiting embodiment, the controller 108 is configured to compute, for each of the candidate value sets, a weighted sum, i.e. a linear combination, of the above-mentioned average temporal duration and average energy consumption, and thereafter to select one of the candidate value sets based on the weighted sums so that the selected value set corresponds to the smallest one of the weighted sums.

[0055] Thus, as illustrated by the above-presented examples, there are many ways to select an advantageous one of the candidate value sets for percussion work after the experiment run. Therefore, the invention is not limited to any specific ways to select an advantageous one of the candidate value sets.

[0056] In an electric percussion device according to an exemplifying and non-limiting embodiment, the controller 108 is configured to control a user interface 109 to propose the selected value set of one or more operating parameter values to a user, i.e. an operator, of the electric percussion device, and to set the one or more operating parameters to have the one or more values contained by the selected value set in response to an acceptance order received via the user interface 109.

[0057] In an electric percussion device according to an exemplifying and non-limiting embodiment, the controller 108 is configured to record, in a memory 110, one or more currently used values of the one or more operating parameters in response to a record order received via the user interface 109. The controller 108 is advantageously configured to associate an identifier with the one or more values to be recorded and to record the identifier in the memory 110 along with the one or more values. Furthermore, the controller 108 is advantageously configured to retrieve one or more values of the one or more operating parameters from the memory 110 and to set the one or more operating parameters to have the retrieved one or more values in response to a situation in which an identifier related to the values to be retrieved is submitted to the controller. The identifier related to recorded operating parameter values may identify for example the material under percussion work, a user i.e. an operator of the electric percussion device, and / or one or more environmental conditions, e.g. temperature and / or a rain vs. dry weather, of an operating environment of the electric percussion device. Thus, it is possible to store and later retrieve operating parameter values which have proved to be advantageous for given material subject to percussion work and / or for a way of working and / or working skills of a given user i.e. an operator of the electric percussion device, and / or for given environmental conditions.

[0058] The implementation of the controller 108 shown in figures 1a and 1 b can be based on one or more analogue circuits, one or more digital processing circuits, or a combination thereof. Each digital processing circuit can be a programmable processor circuit provided with appropriate software, a dedicated hardware processor such as for example an application specific integrated circuit “ASIC”, or a configurable hardware processor such as for example a field programmable gate array “FPGA”. Furthermore, the controller 108 may comprise one or more memory elements each of which can be for example a Random-Access Memory “RAM” element. The memory 110 shown in figures 1a and 1 b can be for example a solid-state drive “SSD” memory.

[0059] It is to be noted that electric percussion devices according to embodiments of the invention are not limited to any specific type or types of linear electric machines. For example, the linear electric machine of an electric percussion device according to an exemplifying and non-limiting embodiment can be a permanent magnet synchronous machine that comprises permanent magnets in a mover, a flux switching permanent magnet synchronous machine ’’FSPMSM” where permanent magnets are located in a stator, a reluctance linear electric machine, or a linear induction machine. In a reluctance linear electric machine, all magnetic flux is produced by electric currents and a magnetic force directed to the mover is generated by reluctance variation based on the design of the mover. Correspondingly, in a linear induction machine, all magnetic flux is produced by electric currents and a magnetic force directed to the mover is generated by currents induced in the mover. Thus, no permanent magnets are needed is a reluctance linear electric machine nor in a linear induction machine. Figure 2 shows a flowchart of a method according to an exemplifying and non-limiting embodiment for controlling an electric percussion device that comprises:

[0060] - a frame attachable to a working machine, the frame comprising attachment members configured to attach to the working machine so that the frame is nondestructively detachable from the working machine,

[0061] - an actuator member linearly movably supported with respect to the frame,

[0062] - a linear electric machine comprising a mover configured to direct impacts to the actuator member, and a stator attached to the frame and provided with windings configured to generate a magnetic force directed to the mover in response to electric current supplied to the windings,

[0063] - a power electronic converter configured to drive the linear electric machine by supplying the electric current to the windings, and

[0064] - a controller configured to control the power electronic converter to drive the linear electric machine so that operation of the electric percussion device fulfills functionality defined by one or more values of one or more operating parameters of the electric percussion device.

[0065] The method comprises the following actions:

[0066] - action 201 : controlling the power electronic converter to carry out an experiment run comprising temporally non-overlapping periods of percussion work during which the actuator member hits material under the percussion work, the one or more operating parameters having during each of the periods of the percussion work one or more candidate values constituting a candidate value set related to the period of the percussion work,

[0067] - action 202: collecting data related to the percussion work during each of the periods of the percussion work during which the candidate value set related to the period of the percussion work is used, and action 203: selecting, after the experiment run and based on the data collected during the periods of the percussion work, one of the candidate value sets to be a selected value set for percussion work after the experiment run.

[0068] In a method according to an exemplifying and non-limiting embodiment, the data collected during the periods of the percussion work expresses temporal durations of the periods of the percussion work. The method according to this exemplifying and non-limiting embodiment comprises computing, for each of the candidate value sets, an average temporal duration of those periods of the percussion work during which the candidate value set under consideration was used, and selecting the one of the candidate value sets based on the average temporal durations so that the selected value set corresponds to the smallest one of the average temporal durations.

[0069] In a method according to an exemplifying and non-limiting embodiment, the data collected during the periods of the percussion work expresses energy consumptions of the electric percussion device during the periods of the percussion work. The method according to this exemplifying and non-limiting embodiment comprises computing, for each of the candidate value sets, an average energy consumption during those periods of the percussion work during which the candidate value set under consideration was used, and selecting the one of the candidate value sets based on the average energy consumptions so that the selected value set corresponds to the smallest one of the average energy consumptions.

[0070] In a method according to an exemplifying and non-limiting embodiment, the one or more operating parameters determine i) a stroke frequency and / or ii) an impact energy of each stroke and / or iii) maximum acceleration of the mover during an impact stroke of the mover when the mover moves towards the actuator member, and / or iv) average acceleration of the mover during an impact stroke of the mover.

[0071] A method according to an exemplifying and non-limiting embodiment comprises controlling a user interface to propose the selected value set to a user of the electric percussion device and setting the one or more operating parameters to have one or more values contained by the selected value set in response to an acceptance order received via the user interface. A method according to an exemplifying and non-limiting embodiment comprises recording, in a memory, one or more currently used values of the one or more operating parameters in response to a record order received via a user interface.

[0072] A method according to an exemplifying and non-limiting embodiment comprises associating an identifier with the one or more currently used values of the one or more operating parameters and recording the identifier in the memory along with the one or more currently used values.

[0073] A method according to an exemplifying and non-limiting embodiment comprises retrieving one or more recorded values of the one or more operating parameters from the memory and setting the one or more operating parameters to have the one or more recorded values in response to a situation in which an identifier associated with the one or more recorded values is submitted to the controller.

[0074] In a method according to an exemplifying and non-limiting embodiment, the above- mentioned identifier identifies: i) the material under the percussion work, ii) a user of the electric percussion device, and / or iii) one or more environmental conditions of an operating environment of the electric percussion device.

[0075] In a method according to an exemplifying and non-limiting embodiment, each candidate value set is used in many of the periods of the percussion work to mitigate an effect of stochastic variation between work performances carried out with different ones of the candidate value sets.

[0076] A computer program according to an exemplifying and non-limiting embodiment comprises computer executable instructions for controlling a programmable controller of an electric percussion device to carry out actions related to a method according to any of the above-described exemplifying and non-limiting embodiments.

[0077] A computer program according to an exemplifying and non-limiting embodiment comprises software modules for controlling an electric percussion device. The software modules comprise computer executable instructions for controlling a programmable controller of the electric percussion device to: - control a power electronic converter of the electric percussion device to carry out an experiment run comprising temporally non-overlapping periods of percussion work during which the actuator member hits material under the percussion work, the one or more operating parameters having during each of the periods of the percussion work one or more candidate values constituting a candidate value set related to the period of the percussion work,

[0078] - collect data related to the percussion work during each of the the periods of the percussion work during which the candidate value set related to the period of the percussion work is used, and

[0079] - select, after the experiment run and based on the data collected during the periods of the percussion work, one of the candidate value sets to be a selected value set for percussion work after the experiment run.

[0080] The software modules can be for example subroutines or functions implemented with programming tools suitable for the programmable controller.

[0081] A computer program product according to an exemplifying and non-limiting embodiment comprises a computer readable medium, e.g. a compact disc “CD”, encoded with a computer program according to an exemplifying embodiment of invention.

[0082] A non-volatile computer readable medium according to an exemplifying and nonlimiting embodiment is encoded with a computer program according to an exemplifying embodiment of invention.

[0083] A signal according to an exemplifying and non-limiting embodiment is encoded to carry information defining a computer program according to an exemplifying embodiment of invention.

[0084] The invention and the embodiments thereof are not limited to the exemplifying and non-limiting embodiments described above. Thus, the specific examples provided in the description given above should not be construed as limiting the scope and / or the applicability of the appended claims. Lists and groups of examples provided in the description given above are not exhaustive unless otherwise explicitly stated.

Claims

What is claimed is:1 . An electric percussion device (100) comprising:- a frame (101 ) attachable to a working machine, the frame comprising attachment members (102) configured to attach to the working machine so that the frame is nondestructively detachable from the working machine,- an actuator member (103) linearly movably supported with respect to the frame (102),- a linear electric machine (104) comprising a mover (105) configured to direct impacts to the actuator member (103), and a stator (106) attached to the frame (102) and provided with windings configured to generate a magnetic force directed to the mover (105) in response to one or more electric currents supplied to the windings,- a power electronic converter (107) configured to drive the linear electric machine by supplying the one or more electric currents to the windings, and- a controller (108) configured to control the power electronic converter to drive the linear electric machine so that operation of the electric percussion device fulfills functionality defined by one or more values of one or more operating parameters, characterized in that the controller is configured to:- control the power electronic converter to carry out an experiment run comprising temporally non-overlapping periods of percussion work during which the actuator member hits material under the percussion work, the one or more operating parameters having, during each of the periods of the percussion work, one or more candidate values constituting a candidate value set related to the period of the percussion work,- collect data related to the percussion work during each of the periods of the percussion work during which the candidate value set related to the period of the percussion work is used, andselect, after the experiment run and based on the data collected during the periods of the percussion work, one of the candidate value sets to be a selected value set for percussion work after the experiment run.

2. An electric percussion device according to claim 1 , wherein the data collected during the periods of the percussion work expresses temporal durations of the periods of the percussion work and the controller (108) is configured to compute, for each of the candidate value sets, an average temporal duration of those periods of the percussion work during which the candidate value set was used and to select the one of the candidate value sets based on the average temporal durations so that the selected value set corresponds to a smallest one of the average temporal durations.

3. An electric percussion device according to claim 1 or 2, wherein the data collected during the periods of the percussion work expresses energy consumptions of the electric percussion device during the periods of the percussion work and the controller (108) is configured to compute, for each of the candidate value sets, an average energy consumption during those periods of the percussion work during which the candidate value set was used and to select the one of the candidate value sets based on the average energy consumptions so that the selected value set corresponds to a smallest one of the average energy consumptions.

4. An electric percussion device according to any one of claims 1 -3, wherein the one or more values of the one or more operating parameters determine at least one of following: i) a stroke frequency, ii) an impact energy of each stroke, iii) maximum acceleration of the mover during an impact stroke of the mover when the mover moves towards the actuator member, and iv) average acceleration of the mover during the impact stroke of the mover.

5. An electric percussion device according to any one of claims 1 -4, wherein the controller (108) is configured to control a user interface (109) to propose the selected value set to a user of the electric percussion device, and to set the one or more operating parameters to have one or more values contained by the selected value set in response to an acceptance order received via the user interface (109).

6. An electric percussion device according to any one of claims 1 -5, wherein the controller (108) is configured to record, in a memory (110), one or more currently used values of the one or more operating parameters in response to a record order received via a user interface (109).

7. An electric percussion device according to claim 6, wherein the controller (108) is configured to associate an identifier with the one or more currently used values of the one or more operating parameters and to record the identifier in the memory (110) along with the one or more currently used values.

8. An electric percussion device according to any one of claims 1 -7, wherein the controller (108) is configured to retrieve one or more recorded values of the one or more operating parameters from a memory (110) and to set the one or more operating parameters to have the one or more recorded values in response to a situation in which an identifier associated with the one or more recorded values is submitted to the controller.

9. An electric percussion device according to claim 7 or 8, wherein the identifier identifies at least one of following: i) the material under the percussion work, ii) a user of the electric percussion device, and iii) one or more environmental conditions of an operating environment of the electric percussion device.

10. An electric percussion device according to any one of claims 1 -9, wherein the controller is configured to use each candidate value set in many of the periods of the percussion work to mitigate an effect of stochastic variation between work performances carried out with different ones of the candidate value sets.

11. A method for controlling an electric percussion device (100) that comprises:- a frame (101 ) attachable to a working machine, the frame comprising attachment members (102) configured to attach to the working machine so that the frame is nondestructively detachable from the working machine, an actuator member (103) linearly movably supported with respect to the frame (102),- a linear electric machine (104) comprising a mover (105) configured to direct impacts to the actuator member (103), and a stator (106) attached to the frame (102) and provided with windings configured to generate a magnetic force directed to the mover (105) in response to one or more electric currents supplied to the windings,- a power electronic converter (107) configured to drive the linear electric machine by supplying the one or more electric currents to the windings, and- a controller (108) configured to control the power electronic converter to drive the linear electric machine so that operation of the electric percussion device fulfills functionality defined by one or more values of one or more operating parameters, characterized in that the method comprises:- controlling (201 ) the power electronic converter to carry out an experiment run comprising temporally non-overlapping periods of percussion work during which the actuator member hits material under the percussion work, the one or more operating parameters having, during each of the periods of the percussion work, one or more candidate values constituting a candidate value set related to the period of the percussion work,- collecting (202) data related to the percussion work during each of the periods of the percussion work during which the candidate value set related to the period of the percussion work is used, and- selecting (203), after the experiment run and based on the data collected during the periods of the percussion work, one of the candidate value sets to be a selected value set for percussion work after the experiment run.

12. A method according to claim 11 , wherein the data collected during the periods of the percussion work expresses temporal durations of the periods of the percussion work and the method comprises computing, for each of the candidate value sets, an average temporal duration of those periods of the percussion work during which the candidate value set was used and selecting the one of the candidate valuesets based on the average temporal durations so that the selected value set corresponds to a smallest one of the average temporal durations.

13. A method according to claim 11 or 12, wherein the data collected during the periods of the percussion work expresses energy consumptions of the electric percussion device during the periods of the percussion work and the method comprises computing, for each of the candidate value sets, an average energy consumption during those periods of the percussion work during which the candidate value set was used and selecting the one of the candidate value sets based on the average energy consumptions so that the selected value set corresponds to a smallest one of the average energy consumptions.

14. A method according to any one of claims 11-13, wherein the one or more values of the one or more operating parameters determine at least one of following: i) a stroke frequency, ii) an impact energy of each stroke, iii) maximum acceleration of the mover during an impact stroke of the mover when the mover moves towards the actuator member, and iv) average acceleration of the mover during the impact stroke of the mover.

15. A method according to any one of claims 11 -14, wherein the method comprises controlling a user interface to propose the selected value set to a user of the electric percussion device and setting the one or more operating parameters to have one or more values contained by the selected value set in response to an acceptance order received via the user interface.

16. A method according to any one of claims 11 -15, wherein the method comprises recording, in a memory, one or more currently used values of the one or more operating parameters in response to a record order received via a user interface.

17. A method according to claim 16, wherein the method comprises associating an identifier with the one or more currently used values of the one or more operating parameters and recording the identifier in the memory together with the one or more currently used values.

18. A method according to any one of claims 11 -17, wherein the method comprises retrieving one or more recorded values of the one or more operating parametersfrom a memory and setting the one or more operating parameters to have the one or more recorded values in response to a situation in which an identifier associated with the one or more recorded values is submitted to the controller.

19. A method according to claim 17 or 18, wherein the identifier identifies at least one of following: i) the material under the percussion work, ii) a user of the electric percussion device, and iii) one or more environmental conditions of an operating environment of the electric percussion device.

20. A method according to any one of claims 11 -19, wherein each candidate value set is used in many of the periods of the percussion work to mitigate an effect of stochastic variation between work performances carried out with different ones of the candidate value sets.

21. A computer program for controlling an electric percussion device (100) that comprises:- a frame (101 ) attachable to a working machine, the frame comprising attachment members (102) configured to attach to the working machine so that the frame is nondestructively detachable from the working machine,- an actuator member (103) linearly movably supported with respect to the frame (102),- a linear electric machine (104) comprising a mover (105) configured to direct impacts to the actuator member (103), and a stator (106) attached to the frame (102) and provided with windings configured to generate a magnetic force directed to the mover (105) in response to one or more electric currents supplied to the windings,- a power electronic converter (107) configured to drive the linear electric machine by supplying the one or more electric currents to the windings, and a programmable controller (108) configured to control the power electronic converter to drive the linear electric machine so that operation of the electricpercussion device fulfills functionality defined by one or more values of one or more operating parameters, characterized in that the computer program comprises computer executable instructions for controlling the programmable controller to:- control the power electronic converter to carry out an experiment run comprising temporally non-overlapping periods of percussion work during which the actuator member hits material under the percussion work, the one or more operating parameters having, during each of the periods of the percussion work, one or more candidate values constituting a candidate value set related to the period of the percussion work,- collect data related to the percussion work during each of the periods of the percussion work during which the candidate value set related to the period of the percussion work is used, and- select, after the experiment run and based on the data collected during the periods of the percussion work, one of the candidate value sets to be a selected value set for percussion work after the experiment run.

22. A computer program according to claim 21 , wherein the computer program comprises computer executable instructions for controlling the programmable controller to use each candidate value set in many of the periods of the percussion work to mitigate an effect of stochastic variation between work performances carried out with different ones of the candidate value sets.

23. A non-volatile computer readable medium encoded with a computer program according to claim 21 or 22.

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