SE2151382A1

SE2151382A1 - System and method for communicating data over mechanical structures on mobile working machines

Info

Publication number: SE2151382A1
Application number: SE2151382A
Authority: SE
Inventors: Krister Ohlsson
Original assignee: Dasa Control Systems Ab
Priority date: 2021-11-11
Filing date: 2021-11-11
Publication date: 2023-05-12
Also published as: SE546326C2

Abstract

A data communication arrangement (100) configured to be attached on a mechanical structure (150) of a mobile working machine (200) is provided. The data communication arrangement (100) comprises a first power-line communication, PLC, device (12) connectable to a first data communication device (10), and a second PLC device (22) connectable to a second data communication device (20). The first PLC device (12) and the second PLC device (22) are attachable on opposite sides (151,153) of an articulated joint (152) of the mechanical structure (150). The first PLC device (12) and the second PLC device (22) are configured to communicate a data signal in an electrical conductor (30) while being electrically connected between the first PLC device (12) and the second PLC device (22).

Description

SYSTEM AND METHOD FOR COMMUNICATING DATA OVER MECHANICAL STRUCTURES ON MOBILE WORKING MACHINES TECHNICAL FIELD The present invention relates systems and methods for communication of data over a mechanical structure on a mobile working machine.

BACKGROUND Communication of data between a maneuver cabin and an implement of a mobile working machine is increasingly important in modern industry. Sending and receiving data to and from, e.g., sensors or controlling an actuator present on a harvester head of a forestry machine is no exception. Today's and tomorrow's sensors, capable of precise and fast measurements, require a responsive, accurate and fast data communication. At the same time, the data communication must be reliable in harsh external environments, which is often the case in environments including heavy machines, such as being weatherproof, impact resistant, and the like. Currently used techniques such as relatively fragile fiber optical cables, CAN bus communication means, call for a faster, more responsive and/or impact resistant alternative.

SUMMARY lt is an object to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination and at least partly solve the above-mentioned problem.

According to a first aspect, there is provided a data communication arrangement configured to be attached on a mechanical structure of a mobile working machine, the data communication arrangement comprising a first power-line communication, PLC, device connectable to a first data communication device, and a second PLC device connectable to a second data communication device, 2 the first PLC device and the second PLC device being attachable on opposite sides of an articulated joint of the mechanical structure, wherein the first PLC device and the second PLC device are configured to communicate a data signal in an electrical conductor while being electrically connected between the first PLC device and the second PLC device.

The mobile working machine may be a forestry machine, an excavator, a tracked or wheeled feller buncher, a bespoke forestry machine, an articulated or rigid wheeled loader, or the like. The articulated structure may be an articulated boom, further discussed below. The mechanical joint is a pivot point of the articulated structure. The articulated joint may below be denoted by the herein equivalent terms mechanical joint, orjoint. A specific side of the mechanical joint thereby refers to a position on the articulated structure, such as in proximity to a free end of an articulated boom at which an implement is attached. An opposite side of the mechanical joint relative to the free end of such an articulated boom may be in or in proximity of a maneuver cabin of the mobile working machine. Alternatively, the opposite side of the mechanical joint relative to the free end may be in proximity of a region of attachment between the articulated boom and a main body of the mobile working machine. The main body is herein understood referring to a load carrying structure, a chassis, a frame, etc. of the mobile working machine. Further, "opposite side" refers to sides relative to the pivot point along the mechanical structure, such as along the extensions of a first and a second boom section of an articulated boom. This applies independent of a degree of articulation of the mechanical structure.

The data communication arrangement hence provide data communication over an electrically conducting cable running along the mechanical structure. Communicating data in electrically conducting cables may facilitate an impact resistant alternative in favor of, e.g., fiber optics- based solutions such as Ethernet, or the like. This may be advantageous when communicating data between a maneuver cabin and an implement of a mobile working machine, which typically operates in harsh environments including physical impacts by, e.g., falling trees, branches, debris, or 3 bending/rotation of cables during operation, or during heavy rain, wind or other weather conditions, etc. The data communication may advantageousiy take place in an already installed power cable of the mobile working machine. This may reduce installation cost and time as well as facilitating maintenance thereby reducing downtime. This may further facilitate replacement of an already installed data communication system, hence being a sustainable alternative as well as extending the economic life of the machine. This may be done without compromising on functionalities or attributes associated with electrical signals occurring in the already installed power cable. Further, Wired data communication arrangements (such as the present PLC arrangement) may facilitate a relatively short latency time. A short latency time may also provide an improved user experience upon controlling an actuator or receiving data from a sensor, etc.

The PLC devices may comprise shock absorbent means. The shock absorbent may be a gel for embedding electronic circuitry in respective PLC device and/or for embedding respective PLC device as such. The gel facilitate the PLC devices to withstand a g force impact of up to 100 g, where g is the normal gravitational acceleration, i.e. approximately 10 m/s^2. The gelation may be done using any adequate compound. The compound preferably has a certain elasticity, both before and after hardening. This may further provide operation in a relatively wide temperature span during a relatively long time span. Such a temperature span may be in the range of -40 to +85 degrees Celsius. The time span may be up to several weeks or even months. This facilitates withstanding of the data communication device in harsh conditions.

The PLC devices may comprise bushings for sealing the PLC devices against liquids. Such liquid may, e.g. be water or oil. This may be done by bushings, preferably made in rubber or other elastic materials.

Respective PLC device may have a physical dimension of a box having side lengths of 1-3 cm. This relatively compact physical dimension may facilitate, e.g. embedding the PLC device in a controller or the like.

The mechanical structure may be an articulated boom. The articulated boom may comprise one or more joints, wherein adjacent joints may be 4 connected by a boom, a beam, or the like. The articulated boom thereby comprises a first and a second end, such that the first end may comprise an implement such as a harvester head, a felling head, grapple or the like, and the second end is attached to the main body of the mobile working machine. Below, if referring to the first data communication device being attachable on the first end of the mechanical structure, it is understood that the first communication device may be directly or indirectly attachable on the first end. For instance, the first data communication device may be attachable at/in a harvester head attached to the first end of the mechanical structure/boom. Similarly, the second data communication device being attachable on the second end of the mechanical structure refers to a direct or indirect attachment. This may include the second data communication device being located in a maneuver cabin of the mobile working machine. The skilled person appreciates that many variations in this respect are possible within the scope of the claims.

The mechanical structure may further comprise any one of a harvester head, a grapple, a feller buncher head, a knuckleboom head, and a shovel head.

Other examples may be a processing head, a felling head, a bunching head, and a felling grapple.

A specific PLC device of the first and the second PLC device may comprise a modulator comprising circuitry configured to execute an orthogonal frequency-division multiplexing, OFDM, modulating function configured to modulate and/or demodulate a data signal received by the specific PLC device.

This may prevent damping, phase shifts, or other perturbations that may affect certain subcarrier waves, hence facilitating reliability of data transmission. Further, CAN traffic may occur, possibly simultaneously, in the same electrical conductor as data is transmitted. Hence, flexibility may be enhanced. OFDM may provide a data transmission bitrate up to approximately 500 Mbit per second, hence facilitating heavy data traffic.

The OFDM modulating function may comprise a Fourier transformation function configured to transform the data signal between a time representation of the data signal and a frequency representation of the data signal.

Carrier waves to be transmitted over the mechanical structure may be generated by an inverse Fourier transformation for transformation from time domain to frequency domain. Due to the discrete nature of the data to be transmitted, an inverse fast Fourier transform, IFFT, may be utilized. This may provide a fast transformation of data, thereby reducing the latency. The frequency of the carrier waves may lie in a frequency range spanning between 1-30 MHz. Hence, the frequency range may thereby lie in the high- frequency, HF, radio spectrum of the electromagnetic spectrum. Other adequate frequency ranges may be possible within the scope of the claims. Upon receiving the carrier waves, which occurs on the opposing side of the mechanical structure, the carrier waves may be transformed back to time domain using a fast Fourier transform. The order of applying the Fourier transform may equally well be reversed by noticing that this can be done by a simple change of dummy variable (and sign in the exponent of the complex exponential) used in the (inverse) Fourier transform equation(s).

The specific PLC device of the first and the second PLC device may further comprise a converter for converting the data signal between an analog representation of the data signal and a digital representation of the data signal The specific PLC device of the first and the second PLC device may further comprise a filter configured to separate high frequency, HF, signals and remaining direct or alternating currents in the data signal.

Preferably, direct currents are used, but also alternating currents may be possible or any combination thereof.

The first data communication device may be a controller configured to receive a sensor output signal, wherein the controller comprises circuitry having calculation capabilities to perform a calculation based on the received 6 sensor output signal. The second data communication device may be a computer configured to receive a human input command.

The computer may be a personal computer, PC, or any equivalent thereof. The computer may comprise any operating system, such as Windows, Linux, MacOS, or any kind of operating systems suitable for mobile electronic devices such as iOS, Android, etc. The computer may alternatively be a tablet or a smartphone, possibly being capable of receiving the human input command via a touch sensitive display or the like. The human input commands may comprise typing or voice commands or a combination thereof. The computer may receive the human input command via a joystick or any equivalent thereof. This may facilitate a convenient communication between the computer and the sensor. Examples of sensors may be a sensor for measuring dimensions of wood, a position sensor, a pressure sensor, a flow sensor, a temperature sensor, a humidity sensor, a scale, or the like.

According to a second aspect, there is provided a method for communicating data between opposite sides of an articulated joint of a mechanical structure of a mobile working machine, the method comprising via an electrical conductor connected between a first power-line communication, PLC, device attachable on a first side of the articulated joint and a second PLC device attachable on a second side of the articulated joint, communicating a data signal between the first and the second PLC device.

The above-mentioned features and advantages of the first aspect, when applicable, apply to this second aspect as well. ln order to avoid undue repetition, reference is made to the above.

The communication of the data signal may further comprise by an orthogonal frequency-division multiplexing, OFDM, modulating function, modulating and/or demodulating the data signal received by a specific PLC device of the first and the second PLC device.

The modulation and/or demodulation of the data signal may further comprise Fourier transforming the data signal between a time representation of the data signal and a frequency representation of the data signal. 7 The method may further comprise converting the data signal between an analog representation of the data signal and a digital representation of the data signal.

The method may further comprise separating high frequency, HF, signals and a remaining direct or alternating current in the data signal.

According to a third aspect, the invention refers to a use of a data communication arrangement according to the first aspect for communicating data on a mobile working machine.

The above-mentioned features of the first aspect, when applicable, apply to this third aspect as well. ln order to avoid undue repetition, reference is made to the above.

A further scope of applicability of the present invention will become apparent from the detailed description given below. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description.

Hence, it is to be understood that this invention is not limited to the particular component parts of the device described or acts of the methods described as such device and method may vary. lt is also to be understood that the terminology used herein is for purpose of describing particular embodiments only and is not intended to be limiting. lt must be noted that, as used in the specification and the appended claim, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements unless the context clearly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps.

BRIEF DESCRIPTION OF THE DRAWINGS 8 The above and other aspects of the present invention will now be described in more detail, with reference to appended figures. The figures should not be considered limiting; instead they are used for explaining and understanding. Like reference numerals refer to like elements throughout.

Fig. 1 schematically shows a data communication arrangement mounted on an articulated boom.

Fig. 2A schematically shows the disclosed approach for power supply and data communication over an articulated boom.

Fig. 2B schematically shows a prior art approach for power supply and data communication over an articulated boom.

Fig. 3 shows, highly schematically, a power-line communication device.

Fig. 4 shows a flowchart of a method for communicating data over an articulated boom.

DETAILED DESCRIPTION The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and to fully convey the scope of the invention to the skilled person. ln connection with Fig. 1, there is schematically shown an example use case of a data communication arrangement 100 mounted on a mechanical structure 150 on a mobile working machine 200. Fig. 2A schematically shows a similar scheme. Hence, Fig. 1 and Fig. 2A may be viewed in parallel in connection with the following description.

The data communication arrangement 100 is herein shown being mounted on an articulated boom of a forestry machine 200. Hence, an articulated boom 150 is a special case of a mechanical structure. Henceforth, the wording articulated boom 150 and mechanical structure 150 may be used interchangeably, which should not confuse the skilled person. 9 The articulated boom 150 comprises an articulated joint 152 over which data can be communicated. The articulated joint 152 is thereby a pivot point between two connected parts 154,156 rotatable with respect to each other. The articulated boom 150 may comprise a plurality of articulated joints 152. The articulated joint articulately connects, directly or indirectly, a first boom section 154 and a second boom section 156. ln the event the mechanica| structure 150 is a Iifting arm, the articulated joint may connect, directly or indirectly, the lifting arm and a main body of the mobile working machine 200. lt is further to be understood that a plurality of articulated joints may be present in connection to the articulated joint 152 separating the first boom section 154 and the second boom section 156. By way of example, for a hydraulically actuated articulated boom, as is normal for, e.g. excavators, a hydraulic actuator connected between the first boom section 154 and the second boom section 156 is often present wherein the hydraulic actuator is attached to respective boom section 154,156 by a secondary articulated joint. The secondary articulated joint(s) thereby has/have differently located pivot point(s) compared to the pivot point of the presently considered articulated joint 152. Generally, the same applies for other involved sections along the articulated boom 150. Further, the articulated boom 150 may have more than two boom sections, where an articulated jointjoins every adjacent pair of boom sections.

The articulated joint 152 may allow a relative movement of the first boom section 154 and the second boom section 156 in one or more degrees of freedom and may restrict movement in one or more other degrees of freedom. The articulated joint may be of any type, e.g., a pin joint, a prismatic joint, a ball joint, a knucklejoint, etc.

The mobile working machine 200 may be a forestry machine, an excavator, a tracked or wheeled feller buncher, a bespoke forestry machine, an articulated or rigid wheeled loader, etc. Combinations thereof may be possible. For instance, should the mobile working machine be an excavator, a forestry attachment may be mounted thereto, etc. Hence, the articulated joint 152 may articulately join a first 154 and a second 156 boom section over which an electrical conductor 30 runs. A plurality of articulated joints may be possible, as described above. ln such a situation the electrical conductor 30 may run over every one of the plurality of articulated joints. A specific side of the articulated joint 152 thereby refers to a position on the mechanical structure 150 or a position on the mobile working machine 200, such as in proximity to a free end 151 of the articulated boom 150 on which an implement 170 is attached, or at a main body of the mobile working 200 machine such as in the maneuver cabin 156. The implement can be tilted and rotated in many ways by means of electrically controllable hydraulics. An opposite side 153 of the articulated joint 152 relative to the free end 151 of the articulated boom 150 may be in or in proximity of a maneuver cabin 153 of the mobile working machine 200. The free end 151 may interchangeably be referred to as "the first end" herein. Alternatively, the opposite side 153 of the articulated joint 152 relative to the free end 151 may be in proximity of a region of attachment 154 between the articulated boom 150 and the main body of the mobile working machine 200. This opposite side 153 may be referred to as "the second end" herein. The skilled person realizes that this applies independent of a degree of articulation of the mechanical structure. Hence, the first end 151, the articulated joint 152 and the second end 153 do not necessarily lie on a straight line, as demonstrated in Fig. 1. The second end 153 may refer to a region within five meters from the point of attachment between the articulated boom 150 and the main body of the mobile working machine 200, and more preferably three meters. The first end 151 may be a region within two meters from an utmost end of the free end of the articulated boom 150, and more preferably one meter. An implement 170, attached to the first end 151 of the articulated boom 150 may be a harvester head 170, a grapple, a feller buncher head, a knuckleboom head, a shovel head, a processing head, a felling head, a bunching head, and a felling grapple. Other implements may be possible. The implement 170 may further comprise a sensor 14 from/to which data may be communicated. The second end 153 of the mechanical structure 150 may be directly or indirectly attached to the main body of the mobile working machine 11 200. The second end 154 of the mechanical structure 150 may thereby include at least a portion of the main body of the mobile working machine 200, such as a cabin 156 from which the mobile working machine 200 including the mechanical structure 150 is controlled. Preferably, the mobile working machine 200 is operated by a human located in the maneuver cabin 156 or in proximity of the mobile working machine 200. However, it is appreciated that the mobile working machine 200 may be operated automatically or remotely. Operation of the mobile working machine 200 may include communicating data between a first data communication device 10 and a second data communication device 20. The mechanical structure 150 further comprises an electrical conductor 30 (already mentioned above) being directly or indirectly electrically connected between the first data communication device 10 and the second data communication device 20. The electrical conductor 30 may run along the mechanical structure 150 as schematically shown in Fig. 1. A portion of the electrical conductor 30 may thereby be located relatively close to the articulated joint 152 of the mechanical structure 150. Should the mechanical structure 150 comprise a plurality of articulated joints, the electrical conductor 30 may, similarly, run over every one of the plurality of articulated joints. Preferably, the electrical conductor 30 is an already installed power cable 30 of the mobile working machine. Such an already installed power cable 30 may allow CAN traffic in both directions as well as power supply. CAN traffic may include maneuver signals, communication with engines, pumps, etc. Hence, power supply, CAN traffic and data communication may all be transported/transmitted in the same electrical conductor 30. As can be seen in Fig. 2B (prior art), these signals are generally transported/transmitted by three different cables: a power cable 32, a CAN cable 34, and an optical cable 36 such as an Ethernet cable or the like. However, the present disclosure refers to the scheme shown in Fig. 2A. Returning to the present disclosure, Fig. 1, and Fig. 2A, the electrical conductor 30 may by way of example be power line cable, already mounted on the mechanical structure 150. The power line cable may be a 24V power 12 line cable. Alternatively, the electrical conductor 30 may form part of a separate cable. ln such a case the separate cable may be installed substantially parallel to the already installed power cable. Another obvious option is that a plurality of electrical conductors may be installed on the mechanical structure 150. One electrical conductor of the plurality of electrical conductors may power valves or hydraulics, whereas another electrical conductor of the plurality of electrical conductors may power less power demanding components such as smaller electronics. lt should be appreciated that each electrical conductor generally comprises two electrical conductors - one for each pole, plus and minus - as is normal for direct current, DC, power cables. The electrical conductor 30 may be a stripped wire or a solid conductor. The electrically conducting material of the electrical conductor 30 may be copper. Any adequate conducting material may although be possible. The stripped or solid conductor is enclosed by a wire insulation made of plastic, rubber, or any sufficient isolating material. The isolated wire may be enclosed by a cable jacket as is almost always the case for normal electrical conductors.

The electrical conductor 30 may be a cable comprising two conductors having a cross section being relatively large. This is normally the case for a power cable for powering relatively power consuming components such as valves, hydraulics, etc. Such a cable may also be used for supplying electric current to smaller, less power demanding electronic devices such as, e.g., sensors. Sometimes, however, a separate thinner cable may be used for the less power demanding electronic devices. A cable comprising one thicker and one thinner conductor may apply herein, wherein data may be communicated in any one of these conductors. Again, it is understood that each such cable may comprise two electrical conductors (plus and minus).

Should a plurality of electrical conductors be present, each electrical conductor of the plurality of electrical conductors may be enclosed by the wire insulation per the above. The plurality of isolated electrical conductors may be enclosed by a single cable jacket. Many other alternatives of isolation of the 13 electrical conductor(s) may be possible, as readily appreciated by the skilled person.

The data communication arrangement 100 comprises a first power-line communication, PLC, device 12. The first PLC device 12 is connectable to the first data communicating device 10.

The data communication arrangement 100 comprises a second power- line communication, PLC, device 22. The second PLC device 22 is connectable to the second data communicating device 20.

As will be described further in the examples below, the first data communication device 10 may be a controller 10, and the second data communication device 20 may be a mobile personal computer 20, PC.

The first PLC device 12 and the second PLC device 22 are attachable on opposite sides 151 ,153 of the articulated joint 152 of the mechanical structure 150. The first PLC device 12 and the second PLC device 22 are configured to communicate a data signal in the electrical conductor 30 while being electrically connected between the first PLC device 12 and the second PLC device 22. Details of the electrical conductor 30 has been discussed above.

The first PLC device 12 may be directly or indirectly connectable to the first data communication device 10. The second PLC device 22 may be directly or indirectly connectable to the second data communication device 20. According to Fig. 1, the first PLC device 12 is shown being mounted on a first end 151 of the mechanical structure 150 and the second PLC device 22 is shown being mounted on a second side 153 of the mechanical structure 150.

To resist the harsh environment in which the data communication arrangement 100 operates, the electronics of the PLC devices 12,22 may be protected by shock absorbent means. The shock absorbent may be a gel embedding electronic circuitry in respective PLC device and/or embedding respective PLC device as such. The gelation may be done using any adequate compound. The gel may in a heated state be poured into/onto the PLC devices 12,22 to seal and protect the electronics. When the gel has 14 cooled the gel hardens to achieve a substantially solid state. The gel however preferably has a certain elasticity, also after hardening, such that the PLC devices 12,22 be protected against vibrations or shocks. The PLC devices 12,22 may further be sealed to withstand liquids such as water or oil. This may be done by bushings, preferably made in rubber or another elastic material/compound. Respective PLC 12,22 device may have a physical dimension of a box having side lengths 1-3 cm. Hence, the PLC devices may be embeddable in a controller or the like. Both the interior and exterior of such a box may be gelled and/or sealed. The PLC devices 12,22 preferably have a lP67 and/or lP69 classification. Below follows a straightforvvard clarifying example use case, related to Figs 1 and 2A: - a sensor 14 situated on a harvester head 170 of a forestry machine 200 measures a physical dimension (e.g., a length of a debarked tree) of a piece of wood, - the sensor 14 transmits a data signal comprising data of the physical dimension to a controller (first communication device) 10, - the controller 10 performs calculations/selections/manipulations based on the received sensor data, - the controller 10 outputs data to the first PLC device 12, to thereafter be transmitted in the electrical conductor 30 to the second PLC device 22, - the second PLC device 22 receives the data and forwards the data to the computer 20 (second data communication device 22) located in the maneuver cabin 156. lt is to be understood that data transmission may occur in the opposite direction, i.e., from the second PLC device 22 to the first PLC device 12. ln connection to Fig. 3 there is schematically shown further details of a PLC device 12;22. The first 12 and the second 22 PLC device may share similar structural and functional features. A specific PLC device of the first 12 and the second PLC device 22 may comprise a modulator 2 comprising circuitry configured to execute an orthogonal frequency-division multiplexing, OFDM, modulating function configured to modulate and/or demodulate a data signal received by the specific PLC device.

The OFDM modulating function may comprise a Fourier transformation function 4 configured to transform the data signal between a time representation of the data signal and a frequency representation of the data signal. The data signal may be constituted by a plurality of carrier waves. Generally, and also herein, a carrier wave is a waveform, typically sinusoidal, that is modulated with an information-bearing signal for the purpose of conveying information. A plurality of carrier waves having different frequencies may be transmitted through a common transmission medium, e.g., the electrical conductor 30 as considered herein. The carrier waves are closely separated, possibly having overlapping spectra. The carrier waves may be generated by an inverse Fourier transformation for transformation from time domain to frequency domain. Due to the discrete nature of the data to be transmitted, an inverse fast Fourier transform, lFFT, may be employed. The frequency of the carrier waves may lie in a frequency range spanning between 1-30 MHz. The frequency range may thereby lie in the high- frequency, HF, radio spectrum of the electromagnetic spectrum. Other adequate frequency ranges may be possible within the claimed scope. Upon receiving the carrier waves, which occurs on the opposing side of the mechanical structure 150, the carrier waves may be transformed back to time domain using a fast Fourier transform. The order of applying the Fourier transform may equally well be reversed by noticing that this can be done by a simple change of dummy variable (and possibly the sign in the exponent of the complex exponential) used in the (inverse) Fourier transform equation(s). Other transformation methods for transforming a signal between a time domain and a frequency domain may be possible, such as a Laplace transformation, or a Z transformation.

The specific PLC device of the first 12 and the second 22 PLC device may further comprise a converter 6 for converting the data signal between an analog representation of the data signal and a digital representation of the data signal. The converter may be a standard analogue to digital, A/D, 16 converter. The converter may, e.g., convert a sinusoidal signal continuously varying within a specific voltage range to be interpreted in quantized steps ranging, e.g., between 0 and 255 for an 8-bit A/D converter. Measuring and storing values of the amplitude of the analogue signal periodically thereby generates a discrete (digital) signal.

A specific PLC device of the first and the second PLC device may further comprise a filter 8 configured to separate high frequency, HF, signals and remaining direct or alternating currents in the data signal. The filter 8 may filter out HF signals to be transmitted over the electrical conductor. Hence the filter may be viewed as a low-pass filter, LPF.

The first data communication 10 device may be a controller 10 configured to receive a sensor output signal, wherein the controller comprises circuitry having calculation capabilities to perform a calculation based on the received sensor output signal. The second data communication 20 device may be a computer 20 configured to receive human input commands. The computer 20 may be a mobile personal computer 20. The computer 20 may be connected to a user interface via an operator display, and to a machine interface communicating with, e.g., an engine or hydraulic pumps, etc. The operator display may be a touch sensitive display based on, e.g. capacitive or resistive technology. Alternatively, or additionally, the operator display may be connected to a keyboard, a keypad, a joystick, a lever, a push button, or the like. The computer 20 may have installed thereon any operating system, OS, such as Windows, Linux, MacOS, or any adequate mobile OS for mobile devices such as Android, iOS, or the like. Apart from being configured to communicate with the first data communication 10 device, the computer 20 may be configured to communicate with other data communication devices, preferably via wireless protocols such as 3G, 4G, 5G, Wi-Fi, Bluetooth, Zigbee, Thread, etc. Such other data communication devices may be situated on nearby mobile working machines, command centers, or elsewhere.

The sensor 14 may be a sensor for measuring dimensions of wood, a position sensor, a pressure sensor, a flow sensor, a temperature sensor, a humidity sensor, a scale, or the like. The controller 12 may receive signals 17 transmitted by the sensor. Such signals may be transmitted by a wire connected between the sensor 14 and the controller 12. Alternatively, the sensor 14 may itself have a built-in controller to perform calculations. Preferably, the controller performs the calculation involved in signals received from the sensor. Hence, all calculations may be performed at the first end of the articulated boom 150 before transmitting corresponding data over the articulated boom 150 to the second communication device 22. Alternatively, the sensor 14 may transmit sensor data to the computer for performing relevant calculations based on the received sensor data. A plurality of sensors may be attached on the first end 151 of the articulated boom 150, as is normal for e.g., modern harvester heads. ln connection with Fig. 4, there is shown a flowchart of a method 300 for communicating data between opposite sides 151 ,153 of an articulated joint 152 of a mechanical structure of a mobile working machine 200. The method 300 comprises, via an electrical conductor connected between a first power-line communication, PLC, device attachable on a first side of the articulated joint and a second PLC device attachable on a second side of the articulated joint, communicating 310 a data signal between the first and the second side of the articulated joint. The features per the above regarding the data communication arrangement 100 applies to the method 300 as well. To avoid repetition, reference to the above is made.

The method 300 may further comprise, by an orthogonal frequency- division multiplexing, OFDM, modulating function, modulating 320 and/or demodulating the data signal received by a specific PLC device of the first and the second PLC device.

The method 300 may further comprise Fourier transforming 330 the data signal between a time representation of the data signal and a frequency representation of the data signal.

The method 300 may further comprise converting 340 the data signal between an analog representation of the data signal and a digital representation of the data signal. 18 The method 300 may further comprise separating high frequency, HF, signals and a remaining direct or alternating current in the data signal.

Accordingiy, and in summary, an approach for communicating data between a free end 151 and a maneuver cabin 156 ofa mobile working machine has been exemplified above in a non-limited way. The data communication arrangement 100 may utilize an already installed power cable 30 in which communication of data is done by power-line communication technology. This provides a reliable and fast data transmission as well as being a weather and impact resistant solution suitable for environments involving violent mechanical impacts and harsh weather conditions.

The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

Claims

1. A data communication arrangement (100) configured to be attached on a mechanical structure (150) of a mobile working machine (200), the data communication arrangement (100) comprising a first power-line communication, PLC, device (12) connectable to a first data communication device (10), a second PLC device (22) connectable to a second data communication device (20), the first PLC device (12) and the second PLC device (22) being attachable on opposite sides (151 ;153) of an articu|ated joint (152) of the mechanical structure (150), wherein the first PLC device (12) and the second PLC device (22) are configured to communicate a data signal in an electrical conductor (30) while being electrically connected between the first PLC device (12) and the second PLC device (22).

2. The data communication arrangement (100) according to claim 1, wherein the mechanical structure (150) is an articu|ated boom (150).

3. The data communication arrangement (100) according to claim 1 or 2, wherein the mechanical structure (150) further comprises any one of a harvester head (170), a grapple, a feller buncher head, a knuckleboom head, and a shovel head.

4. The data communication arrangement (100) according to any one of claims 1-3, wherein a specific PLC device (12,22) of the first (12) and the second (22) PLC device comprises a modulator (2) comprising circuitry configured to execute an orthogonal frequency-division multiplexing, OFDM, modulating function configured to modulate and/or demodulate a data signal received by the specific PLC device.

5. The data communication arrangement (100) according to claim 4, wherein the OFDM modulating function comprises a Fourier transformation function (4) configured to transform the data signal between a time representation of the data signal and a frequency representation of the data signal.

6. The data communication arrangement (100) according to any one of claims 1-5, wherein a specific PLC device (12,22) of the first (12) and the second (22) PLC device further comprises a converter (6) for converting the data signal between an analog representation of the data signal and a digital representation of the data signal.

7. The data communication arrangement (100) according to any one of claims 1-6, wherein the specific PLC device of the first (12) and the second (22) PLC device further comprises a filter (8) configured to separate high frequency, HF, signals and a remaining direct or alternating current in the data signal.

8. The data communication arrangement (100) according to claim 1, wherein the first data communication device (10) is a controller (10) configured to receive a sensor output signal, wherein the controller comprises circuitry having calculation capabilities to perform a calculation based on the received sensor output signal, and the second data communication device (20) is a computer (20) configured to receive human input commands.

9. A method (300) for communicating data between opposite sides (151 ,153) of an articulated joint (152) ofa mechanical structure (150) ofa mobile working machine (200), the method comprising via an electrical conductor (30) connected between a first power-line communication, PLC, device (10) attachable on a first side (151) of the articulated joint (152) and a second PLC device (153) attachable on a second side (153) of the articulated joint (152), communicating (310) a data signal between the first (12) and the second (22) PLC device.

10. The method (300) according to claim 9, wherein the communication (310) of the data signal further comprises by an orthogonal frequency-division multiplexing, OFDM, modulating function, modulating (320) and/or demodulating the data signal received by a specific PLC device (12,22) of the first (12) and the second (22) PLC device.

11. The method (300) according to claims 9 or 10, wherein the modulation (320) and/or demodulation of the data signal further comprises Fourier transforming (330) the data signal between a time representation of the data signal and a frequency representation of the data signal.

12. The method (300) according to claim 9, further comprising converting (340) the data signal between an analog representation of the data signal and a digital representation of the data signal.

13. The method (300) according to claim 9, further comprising separating (350) high frequency, HF, signals and a remaining direct or alternating current in the data signal.

14. Use of a data communication arrangement (100) according to any one of claims 1-8 for communicating data on a mobile working machine (200).