DEVICE WITH ELECTRIC TOOL FOR CUTTING OR SHREDDING PLANTS AND METHOD FOR CONTROLLING SUCH A DEVICE

Abstract

DEVICE WITH ELECTRIC TOOL FOR CUTTING OR SHREDDING PLANTS AND METHOD FOR CONTROLLING SUCH A DEVICE The invention relates to a device with an electric tool (9) for cutting or shredding plants, which is associated with a vehicle (V) comprising at least one chassis, an electrical source, control and command elements, and first connection elements (A) connected to the electrical source and / or the control and command elements. The device comprises a housing element with removable fasteners for the chassis and second connection elements (5) removably connectable to the first connection elements (A). The device includes a support element (7) interconnected between the housing element and the electric tool (9) for supporting and / or moving the latter. The electric tool (9) is driven by its own electric motor (11) connected to the second connection elements (5). Fig. 4

Description

Title of the invention: DEVICE WITH ELECTRIC TOOL FOR CUTTING OR SHREDDING PLANTS AND METHOD FOR CONTROLLING SUCH A DEVICE

[0001] The present invention falls within the sector concerning agriculture, the cutting or shredding of plants and in general within the sector of medium and long-distance treatment or treatments and relates in particular to a device with an electric tool for cutting or shredding plants suitable, for example, for agriculture, maintenance of green spaces and alternatively, also for cleaning roads and infrastructure or other treatments, such as washing, disinfection, spraying of powders or liquids, for example for cleaning photovoltaic panels, for the control of mosquitoes or other insects and against pathogens when the distribution tools are electric.

[0002] The invention also relates to a method for controlling such a device.

[0003] There are articulated arm devices for agriculture in which the tool, for example a rotor for cutting grass or for shredding branches or for maintaining roadsides or the like, is driven by an electric motor powered, by means of respective electrical control devices, by a generator driven by a power take-off of a vehicle, for example a tractor or a truck, on which the device is mounted. This configuration is known, for example, from patent application no. IT 201992900269607 filed (in the name of the same proprietor as this document) on 04 / 11 / 1992 and published on 04 / 05 / 1994.

[0004] One disadvantage of these known devices is that the considerable cost of the generator can only be recouped through the use of the device to which it is associated, the use of which is often limited to a certain seasonality.

[0005] Another disadvantage is the risk associated with connecting known devices to the vehicle's power take-off by cardan joint, because, as is known, connecting to the power take-off by cardan joint is one of the main risk factors, even a very serious one, for those who use these devices both during operation and during the connection and disconnection phases.

[0006] Another disadvantage is that the possibility and mounting position of the known device are determined and limited by the characteristics of the vehicle; in addition, this known device can only be installed on vehicles equipped with a power take-off and if the latter is at the front, the device cannot be mounted or must necessarily be mounted at the front.

[0007] Another disadvantage of known devices operating with an electric tool is that they are subject to mechanical and / or electrical overloads when what is being worked has unexpected characteristics, for example the presence of shrubs or trunks that are thicker or closer than expected, or in the case of uneven ground, or in the case of plants or other bodies of unusual resistance, etc., and the prevention of damage to the device is attributed to the promptness and constant vigilance of the operator.

[0008] Another disadvantage of known devices is that they are not able to provide feedback on the activity performed.

[0009] An objective of the present invention is to provide a device with an electric tool for gardening which does not include its own electric generator and which is suitable for the most modern operating vehicles.

[0010] Another objective is to propose a device that can be easily coupled and separated from a vehicle without the use of mechanical rotating connections and that guarantees the safety of workers during the coupling, separation and operation phases.

[0011] Another objective is to propose a device that can be more easily coupled to the front or rear of the respective vehicle, depending on operational needs.

[0012] Other objectives are to propose a device that can help the operator to assess working conditions and / or that can issue alarms when abnormal conditions occur and / or that can autonomously adapt its operation to contingent operating conditions in order to reduce the risk of overloads and damage to the device or from objects facing it.

[0013] Another objective is to propose a suitable device for gardening, agriculture and suitable for other sectors such as cleaning, disinfection and others.

[0014] Another objective is to propose a method for controlling this device in order to ensure its safe and efficient operation.

[0015] Another objective of the method is to be able to provide feedback on certain parameters concerning the work performed and / or to provide data which can be derived from said feedback.

[0016] The earlier documents EP 3 360 404 Al, EP 3 469 872 Al and US 5 794 422 A refer to existing respective devices for gardening.

[0017] The present invention relates to a device with an electric tool for maintaining green spaces that is suitable for being associated with a vehicle comprising at least one chassis, an electrical source, control and command elements, and first connection elements connected to at least one of the electrical source and the control and command elements, said device comprising an element of a housing with removable fixings for said chassis and second connection elements which are capable of being removably connected to the first connection elements; said device comprising a support element interconnected between the housing element and said power tool for the support and / or movement of the latter which is driven by its own electric motor connected to said second connection elements and, in an operating state in which the device is assembled on the vehicle, powered by the vehicle's electrical source where the connection between the electric motor and the second connection elements is made via a control and command unit operated by an operator via a respective user interface and which includes at least one power distribution unit connected to the second connection elements,an inverter unit comprising power supply connections to the power distribution unit and the electric motor and a control unit in data link via a communication line with at least the power distribution unit and / or with the inverter unit; said device being characterized in that the power tool comprises sensors and detectors including at least one of an electric motor encoder, a thermal sensor and an electric motor vibration detector in data link with the inverter unit (and / or with the control unit via the communication line) and comprises a remotely actuated friction brake on a shaft of the electric motor driven by the inverter unit and / or by the control unit or an electric energy regeneration braking system connected to the electric motor and an electric storage element.

[0018] According to a particular feature of the invention, the device includes a cooling element for the circulation of a cooling fluid through at least one ventilated radiator and at least one between a heat exchanger of the inverter unit and a heat exchanger of the electric motor.

[0019] According to a particular feature of the invention, the device includes at least one interface element for an operator comprising at least one of the controls of the electric tool and optionally of the support element, a display device for the status and / or operating parameters of the device, visual and / or audible alarm means, where such an interface element is autonomous or is integrated into the control and command elements of the vehicle.

[0020] According to a particular feature of the invention, the device comprises an electrical accumulator element in electrical power connection with the inverter unit or interconnected between the electrical power distribution unit and the inverter unit and controlled in charge and supply by the inverter unit or by the control unit.

[0021] According to a particular feature of the invention, the first connection elements and the second connection elements, or other specific removable connections, connect the communication line to at least one between the control of the vehicle interface element and a digital vehicle control unit.

[0022] The present invention also relates to a method for controlling a device as described above, characterized in that it comprises at least one of the following phases:

[0023] - slow down the motor's rotational speed by means of the inverter unit when the latter or the sensors and detectors of the electric motor detect during a time interval of a predetermined duration that the power absorbed during the cutting phase is less than a predetermined value;

[0024] - generate by means of the control unit and emit by means of an element interface a warning to the operator regarding the possibility of increasing the vehicle's forward speed when the sensors and detectors of the electric motor or inverter unit detect during a predetermined time interval that the power absorbed during the cutting phase is less than a predetermined value;

[0025] - generate via the control unit and emit via an interface element a warning to the operator regarding the opportunity or necessity to reduce the forward speed when the inverter unit or the sensors and detectors of the electric motor detect during a predetermined time interval that the power absorbed during the cutting phase is greater than a predetermined value or when they detect that this value is greater than 95% of the maximum electrical power that is capable of being supplied by the vehicle;

[0026] - generate via the control unit and emit via an interface element a warning to the operator concerning the opportunity or necessity of lifting the power tool by a certain amount when the sensors and detectors of the electric motor or the inverter unit detect during a time interval of a predetermined duration that the power absorbed during the cutting phase is greater than a predetermined value or when they detect that this value is greater than 95% of the maximum electrical power that is capable of being supplied by the vehicle;

[0027] and by the fact that it comprises the following phases:

[0028] - store in the control unit data sequences provided by the unit inverter and / or by the sensors and detectors of the electric motor, process this data to obtain useful information to estimate the type and / or extent of work performed by the power tool and / or to plan maintenance of the device;

[0029] - generate via the control unit and emit via the interface element and / or the digital control unit of the vehicle alarms or commands in order to reduce or stop the power tool or vehicle based on said useful information.

[0030] According to a particular feature of the invention, the process comprises the following phases:

[0031] - detect by means of an algorithm of the control unit which receives and uses the rotational speed and vibration signals provided by sensors and detectors including at least the electric motor encoder and vibration detector, critical rotational speeds and / or critical rotational speed ranges in which vibrations are at their maximum or above a predefined threshold or exhibit a predefined critical tendency;

[0032] - store in the control unit or in a memory connected to that unit said critical rotational speeds;

[0033] - control the motor via the control unit to avoid a operating at such critical speeds by staying below these speeds or exceeding them as briefly as possible.

[0034] According to a particular feature of the invention, the method comprises: generating by means of an algorithm of the control unit a command to increase or decrease the forward speed when the sensors and detectors of the electric motor and / or the inverter unit detect during a time interval of a predetermined duration that the power absorbed during the cutting phase is respectively less than or greater than a predetermined value, transmitting this command by means of the communication line at least to the electrical power distribution unit and / or to the inverter unit to regulate the increase or decrease of the forward speed of the vehicle automatically, without the intervention of the operator.

[0035] The features of the invention are highlighted below with particular reference to the accompanying drawings in which:

[0036] [Fig-1] illustrates a partial top view of the device with a power tool for cutting or shredding plants, the subject of the present invention, associated with a vehicle consisting of an agricultural tractor;

[0037] [Fig.2] illustrates a rear view of the device and the vehicle of [Fig.1];

[0038] [Fig.3] illustrates an enlarged view of an element of [Fig.2], in which some Parts have been removed to better highlight others;

[0039] [Fig.4] illustrates a schematic view of the device of [Fig.1] associated with the vehicle.

[0040] With reference to Figures 1 to 4, the number 1 designates the device with a tool electric for gardening, or for other and different applications, the subject of the present invention. This device with an electric tool for cutting or shredding plants can be associated with a vehicle V equipped with at least one chassis T, an electric source E, control and command elements C and first electrical connection elements A.

[0041] These first connection elements A are intended to create electrical power connections and optionally data connections, and may be, for example, of a single-connector type or a multi-connector type. The first connection elements A are connected to the electrical source, to allow its connection to an electrical load such as an electric motor, and are optionally connected via digital and / or analog signal to the vehicle's control and command elements C. The vehicle V may consist, for example, of a tractor, a truck, or another type of handling vehicle.

[0042] The device 1 comprises a housing element 3, for example made of metal tubes and / or plates, formed and welded with removable fasteners for said frame T, and it also comprises second connection elements 5 which can be removably attached to the first connection elements A of the vehicle V to draw electrical power from it and optionally to create a data and / or signal connection between the vehicle and the device. The device 1 includes a support element 7 interconnected between the housing element 3 and said power tool 9 for supporting and / or moving the latter 9.This support element 7 can be, for example, an articulated arm with electrical or hydraulic operation, in the latter case the vehicle is equipped with a hydraulic pump which supplies, by means of separable hydraulic connectors, a circuit for the actuation of the hydraulic actuators, for example of the linear cylinder type, of the support element 7 of the device 1. .

[0043] Alternatively, the hydraulic pump can be of the self-contained type, for example driven by a combustion or electric motor, and installed on the vehicle or connected to the device 1. The electric tool 9 is driven by its own electric motor 11 connected to said second connection elements 5. In an operating state in which the device 1 is assembled on the vehicle V, this electric motor is thus powered by the electrical source of the vehicle V.

[0044] In the embodiment of the device illustrated in the Figures, the power tool 9 is provided with a cutting or mowing rotor connected to its own electric motor 11 or electric geared motor by means of a gear train or by means of chains and sprockets or, preferably, by means of one or more belts engaged in pulleys keyed to the shafts of the motor and the rotor. It is also provided that the rotor shaft and the output shaft of a geared motor are coaxial and connected to each other, either rigidly or by means of a flexible coupling. In In all cases, the electric motor and the transmission to the rotor are protected by a container attached to the rotor frame.

[0045] Preferably, and as illustrated in the Figures, the vehicle V consists of a tractor equipped with an electrical source E, for example, consisting of a generator driven by a thermal engine of the vehicle or, better, consisting of electrical accumulators or combustion cells, also known as fuel cells. The vehicle V is equipped with a hydraulic pump to actuate the hydraulic actuators of the support element 7, which consists of a hydraulic articulated arm. As provided, the device includes a power tool consisting of a cutting head or cutter bar or the like, mechanically connected to the vehicle by the support element 7, which consists of an articulated arm.

[0046] The vehicle's electrical source powers the electric motor of the cutting head or cutter bar; the vehicle's hydraulic pump operates the actuators of the articulated arm. The invention provides numerous alternatives to this form of the device for gardening; for example, the power tool may include rotating cleaning brushes driven by the electric motor and carried by the support element consisting of a hydraulic, manual, or electric lift attached to the vehicle, such a vehicle and device being able to be used for cleaning roads or large surfaces.Another alternative is for the device to include a tool consisting of an electric pump with a dispenser or nozzle for a washing liquid, insecticide fluid, or disinfectant. This tool is connected to the vehicle via a support element consisting of a fixed, adjustable, or manually, electrically, or hydraulically oriented jet guide. For example, the vehicle could be a van or pickup truck with an electrical power source, on which the housing element 3 is mounted with the support element 7, which consists of a bracket or arm for the electric tool 9, designed to dispense a pesticide for urban mosquito or other insect control.The removable fixings of the housing element 3 of the device for connection to the vehicle chassis T consist of screws and / or screw-nuts and / or joints or lever clamps for additional chassis elements T and the first connection elements A and the second connection elements 5, as well as the hydraulic line connectors linking the hydraulic pump to the device, which are of the quick-connect and disconnect type; these configurations allow for simple and quick installation or removal of the device from the vehicle, which can then be made available for other applications when the device's functions are not required. The electric motor 11 of the device 1 is connected to the second connection elements 5 by means of a control and command unit 13. an analog and / or digital electronic type, which receives commands given by an operator by means of at least one respective user interface dedicated to the device and / or common to the vehicle and preferably installed in the vehicle cab in a position clearly visible to the operator. Said control and command unit 13 comprises at least one electrical power distribution unit 15 connected to the second connection elements 5, an inverter unit 17 having electrical power supply connections to the electrical power distribution unit 15 and to the electric motor 11 and a control unit 19 in data link via at least one communication line 21 with the electrical power distribution unit 15 and / or with the inverter unit 17.The electrical power distribution unit 15 can be equipped, for example, with terminals and / or connectors and / or electrical power distributors and possibly with data connections and / or switches or the like.

[0047] The electrical power distribution unit 15 distributes electrical power and possibly the data stream to said elements 17, 19 of the control and command unit 13.

[0048] The communication line 21 may be, for example, of the RS-485 differential serial type, coaxial or other and of the CAN-BUS or Ethernet type or different and it may also optionally be provided with power supply lines belonging to the electrical power distribution unit 15 for the power supply of the electrical and electronic circuits of the elements of the control and command unit 13.

[0049] The device also includes a cooling unit 23 equipped with an electric pump for circulating a cooling fluid through at least one ventilated radiator 24 and at least one between a heat exchanger of the inverter unit 17 and a heat exchanger of the electric motor 11. The water connections of the circulation pump, which, for reasons of compactness, can be installed in the housing of the control and command unit 13, are partially illustrated on [Fig.4] by curved lines of increased thickness.

[0050] The control and command unit 13 may also be equipped with a switching and connection element 22 (for example having magnetic or semiconductor switches and / or relays or the like and possibly a fuse or other type of protection) placed on the power supply lines of all or part of the other elements 17, 19, 23 of the control and command unit 13, to which it may also be connected by means of the communication line 21.

[0051] The switching and connecting element 22 supplies electrical energy to said elements of the control and command unit 13 and selectively interrupts it and transfers the exchange of data between them.

[0052] These elements can optionally be put into data communication with the vehicle V (and in particular with its control unit and its user interface) by means of the communication line 21, the electrical power distribution unit 15 and the first A and second 5 connection elements.

[0053] As can be seen, the device includes at least one interface element 27, 29 for an operator; each of these elements is provided with at least one of the controls of the electric tool 9 and possibly of the support element 7, obviously only if it is of the type provided with its own movement actuators; in addition, each interface element 27, 29 can be provided with a display device for the status and / or operating parameters of the device, means of visual and / or audible alarm when this interface element 27 is dedicated and specific, or "autonomous", and / or if it 29 is integrated into the control and command elements C of the vehicle V.

[0054] It is also provided that the communication line 21 or the control unit 19 is in data link with a vehicle control unit to receive data from it and / or to transmit to it speed limitation or stop commands based on the state of the device, in particular in the event of critical situations or failures of such a device.

[0055] Optionally, the device 1 may include an electric storage element 31 in electrical power connection with the inverter unit 17 or interconnected between the electrical power distribution unit 15 and the inverter unit 17 and whose charge and supply are controlled by the inverter unit 17 or by the control unit 19 to which it may be connected via the communication line 21.

[0056] The electrical storage element 31, comprising for example lithium-ion or lithium-polymer batteries or at least one solid-state storage unit, can be maintained at a certain predetermined charge level (for example by charging it with energy from the vehicle's electrical source or by recharging it with an electrical supply when the vehicle is stationary) and used by the inverter unit 17 to provide peak electrical power, exceeding that available from the vehicle, and / or to serve as a "reserve" when the vehicle's electrical source is about to run out or is discharged.It is also intended that the inverter unit 17 can recharge the electric storage element 31 with the energy supplied by the electric motor 11 when it is driven by the inertia of the rotor of the shredder or grass trimmer; in fact, whenever the tool is running idle, for example when cutting discontinuous hedges or bushes far apart, the control and command unit 13 and / or its inverter unit 17 interrupt the electrical supply to the motor 11 to avoid overspeeding. and / or risky conditions; therefore the control and command unit 13 can be programmed to recover at least part of the rotational kinetic energy of the tool, which would otherwise be totally dissipated, by a respective braking element, in order to recharge the electrical accumulator element 31.

[0057] The power tool 9 can be equipped, in addition to the aforementioned braking element, with sensors and detectors including at least one of the encoders for the rotational speed of the electric motor 11 or of the tool's rotor, thermal detectors for the electric motor 11 and / or for vibrations of the power tool; these sensors and detectors are in data link with the inverter unit 17 and / or with the control unit 19 and / or with the communication line 21 to provide the control and command unit 13 with data on the state of the tool.The braking element, for example of the friction type, is connected to the shaft of the electric motor 11 or the rotor of the tool and is remotely actuated by the inverter unit 17 and / or by the control unit 19 or, if the device is provided with said energy recovery, this braking element is actuated in a coordinated manner by the electrically typed energy recovery and is connected to the electric motor 11 and to the electric storage element 31.

[0058] To ensure the programmed, controlled and coordinated operation of the device, the first connection elements A and the second connection elements 5 or other specific removable connections establish a data connection between the communication line 21 and at least one between the control of the interface element 29 of the vehicle and the digital control unit of the vehicle V.

[0059] The method, which is the subject of the present invention, for controlling the device 1, comprises at least one of the following phases: - slow down the rotational speed of the motor 11 by means of the energy recovery functions and / or the actuation of the braking element of the inverter unit 17 when the sensors and detectors of the electric motor 11 detect during a time interval of a predetermined duration that the power absorbed during the cutting phase is less than a predetermined value; - generate by means of the control unit 19 and issue by means of an interface element 27, 29 a warning to the operator concerning the possibility of increasing the forward speed of the vehicle V when the sensors and detectors of the electric motor 11 detect during a time interval of a predetermined duration that the power absorbed during the cutting phase is less than a predetermined value; - generate, using the control unit 19, and issue, using an interface element 27, 29, a warning to the operator regarding the opportunity or necessity of reducing the forward speed when the sensors and detectors of the electric motor 11 detect during a predetermined time interval that the power absorbed during the cutting phase is greater than a predetermined value or when they detect that this value is greater than 95% of the maximum electrical power that can be supplied by the vehicle V because too heavy a job is being carried out, which could lead to clogging of the rotor and poor cutting quality; - generate by means of the control unit 19 and issue by means of an interface element 27, 29 a warning to the operator concerning the advisability or necessity of lifting the electric tool 9 by means of the active support element 7 when the sensors and detectors of the electric motor 11 detect during a predetermined time interval that the power absorbed during the cutting phase is greater than a predetermined value or when they detect that this value is greater than 95% of the maximum electrical power that can be supplied by the vehicle V. If, despite the reduction in forward speed, the power absorbed remains high, a signal is sent which "recommends" raising the head slightly and making a second pass to complete the mowing operation.

[0060] The process may also include the following phases: - store in the control unit 19 data sequences provided by the inverter unit 17 and / or the sensors and detectors of the electric motor 11, process this data to obtain information useful for estimating the type and / or extent of work performed by the electric tool 9 and / or for programming the maintenance of the device; - generate via the control unit 19 and issue via the interface element 27, 29 and / or the digital control unit of the vehicle V alarms or commands to reduce or stop the power tool 9 or the vehicle V on the basis of said useful information.

[0061] The process also includes the following phases: - detect, by means of an algorithm of the control unit 19 which receives and uses the rotational speed and vibration signals provided by the sensors and detectors including at least the encoder of the electric motor 11 and the vibration detector, the critical rotational speeds and / or the critical rotational speed ranges in which the vibrations are maximum or above a predefined threshold or exhibit a predefined critical trend; - store said critical rotation speeds in the control unit 19 or in a memory connected to this unit; - control the motor by means of the control unit 19 to avoid operation at such critical speeds by staying below these speeds or exceeding them as briefly as possible.

[0062] In addition, the method also envisages generating, by means of an algorithm of the control unit 19, a command to increase or decrease the forward speed when the sensors and detectors of the electric motor 11 and / or the inverter unit 17 detect during a time interval of a predetermined duration that the power absorbed during the cutting phase is respectively less than or greater than a predetermined value, of transmitting this command by means of the communication line 21 at least to the electrical power distribution unit 15 and / or to the inverter unit 17 to regulate the increase or decrease of the forward speed of the vehicle V automatically, without the intervention of the operator.

Claims

1. Demands Device (1) with an electric tool (9) for the maintenance of green spaces which is suitable for being associated with a vehicle (V) comprising at least one chassis (T), an electric power source (E), control and command elements (C) and first connection elements (A) connected to at least one between the electric power source (E) and the control and command elements (C), said device (1) comprising a housing element (3) with removable fixings for said chassis (T) and second connection elements (5) which are suitable for being removably connected to the first connection elements (A); said device (1) comprising a support element (7) interconnected between the housing element (3) and said electric tool (9) for the support and / or movement of the latter (9) which is driven by its own electric motor (11) connected to said second connection elements (5) and,in an operating state in which the device (1) is assembled on the vehicle (V), powered by the electrical source (C) of the vehicle (V) where the connection between the electric motor (11) and the second connection elements (5) is made via a control and command unit (13) operated by an operator via a respective user interface and which includes at least one electrical power distribution unit (15) connected to the second connection elements (5),an inverter unit (17) comprising power supply connections to the power distribution unit (15) and to the electric motor (11) and a control unit (19) in data link via a communication line (21) with at least the power distribution unit (15) and / or with the inverter unit (17); said device (1) being characterized in that the power tool (9) comprises sensors and detectors including at least one between an encoder of the electric motor (11), a thermal sensor and a vibration detector of the electric motor (11) in data link with the inverter unit (17) and / or with the control unit (19) via the communication line (21) and comprises a remotely actuated friction brake of a shaft of the electric motor (11) actuated by the inverter unit (17) and / or by the control unit (19) or a system, electrical energy recovery braking connected to the electric motor (11) and an electrical accumulator element (31).

2. Device according to claim 1, characterized in that it comprises a cooling element (23) for the circulation of a cooling fluid through at least one ventilated radiator (24) and at least one between a heat exchanger of the inverter unit (17) and a heat exchanger of the electric motor (11).

3. Device according to claim 1 or 2, characterized in that it comprises at least one interface element (27, 29) for an operator comprising at least one between controls of the power tool (9) and optionally of the support element (7), a display device for the status and / or operating parameters of the device (1), means for visual and / or audible alarm, where such interface element (27) is autonomous or it (29) is integrated into the control and command elements (C) of the vehicle (V).

4. Device according to any one of claims 1 to 3, characterized in that it comprises an electrical storage element (31) in electrical power connection with the inverter unit (17) or interconnected between the electrical power distribution unit (15) and the inverter unit (17) and controlled in charge and supply by the inverter unit (17) or by the control unit (19).

5. Device according to any one of claims 1 to 4, characterized in that the first connection elements (A) and the second connection elements (5), or other specific removable connections, connect the communication line (21) to at least one between the control of the interface element (29) of the vehicle (V) and a digital control unit of the vehicle (V).

6. A method for controlling a device according to any one of the preceding claims 1 to 5, characterized in that it comprises at least one of the following phases: slow down the rotational speed of the motor (11) by means of the inverter unit (17) when the latter (17) or the sensors and detectors of the electric motor (11) detect during a time interval of a predetermined duration that the power absorbed during the cutting phase is less than a predetermined value; generate by means of the control unit (19) and issue by means of an interface element (27, 29) a warning to the operator concerning the possibility of increasing the forward speed of the vehicle (V) when the sensors and detectors of the electric motor (11) or the inverter unit (17) detect during a time interval of a predetermined duration that the power absorbed during the cutting phase is less than a predetermined value; generate via the control unit (19) and issue via an interface element (27, 29) a warning to the operator regarding the opportunity or the need to reduce the forward speed when the inverter unit (17) or the sensors and detectors of the electric motor (11) detect during a predetermined time interval that the power absorbed during the cutting phase is greater than a predetermined value or when they detect that this value is greater than 95% of the maximum electrical power that is capable of being supplied by the vehicle (V); generate via the control unit (19) and issue via an interface element (27, 29) a warning to the operator regarding the advisability or necessity of lifting the power tool (9) by a certain amount when the sensors and detectors of the electric motor (11) or the inverter unit (17) detect, during a predetermined time interval, that the power absorbed during the cutting phase exceeds a predetermined value, or when they detect that this value is greater than 95% of the maximum electrical power that is capable of being supplied by the vehicle (V); and by the fact that it includes the following phases: - store in the control unit (19) data sequences provided by the inverter unit (17) and / or by the sensors and detectors of the electric motor (11), process this data to obtain information useful for estimating the type and / or extent of work performed by the power tool (9) and / or for planning maintenance of the device (1); - generate via the control unit (19) and issue via the interface element (27, 29) and / or the digital control unit of the vehicle (V) alarms or commands in order to reduce or stop the power tool (9) or the vehicle (V) on the basis of said useful information.

7. A method according to claim 6, characterized in that it comprises the following phases: - detect by means of an algorithm of the control unit (19) which receives and uses the rotational speed and vibration signals provided by the sensors and detectors including at least the encoder of the electric motor (11) and the vibration detector, critical rotational speeds and / or critical rotational speed ranges in which the vibrations are maximum or greater than a predefined threshold or exhibit a predefined critical tendency; - store in the control unit (19) or in a memory connected to this unit the said critical rotation speeds; - control the motor via the control unit (19) to avoid operation at such critical speeds by staying below these speeds or exceeding them as briefly as possible.

8. A method according to claim 6 or 7, characterized in that it comprises: generating, via an algorithm, the unit of command (19) a command to increase or decrease the forward speed when the sensors and detectors of the electric motor (11) and / or the inverter unit (17) detect during a time interval of a predetermined duration that the power absorbed during the cutting phase is respectively less than or greater than a predetermined value, transmit this command via the communication line (21) at least to the electrical power distribution unit (15) and / or to the inverter unit (17) to regulate the increase or decrease of the forward speed of the vehicle (V) automatically, without the intervention of the operator.

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