Drone for the distribution of a liquid substance, in particular for precision agriculture

Abstract

The present invention relates to a drone (1) for the distribution of a liquid substance, in particular for precision agriculture, comprising: - a central body (2), with which at least one rotor (3) is associated; - a distribution system (10) for distributing said liquid substance, wherein the distribution system (10) comprises a tank (11), adapted to contain said liquid substance, and at least one nozzle (10A) for distributing or spraying the liquid substance contained in the tank (11), and wherein said tank (11) is associated with the central body (2) of the drone (1). The peculiar feature of the present invention lies in the fact that said tank (11) comprises a main body (11 A) with a polygonal geometry that provides an axisymmetric property, wherein said main body (11 A) has symmetry about a vertical axis centred in the centre of mass of the tank (11), and wherein said main body (11A) of the tank (11) is shaped substantially as a hollow prism with a polygonal base.

Description

[0001] DRONE FOR THE DISTRIBUTION OF A LIQUID SUBSTANCE, IN PARTICULAR FOR PRECISION AGRICULTURE

[0002] DESCRIPTION

[0003] The present invention relates to a drone for the distribution of a liquid substance, in particular for precision agriculture, according to the preamble of claim 1. In particular, in the present disclosure the term “distribution” refers to the application (e.g. by spraying) of a substance in substantially liquid form onto a surface over which a drone flies. Said substantially liquid substance may comprise pesticides, insecticides, fertilizers, and the like; moreover, the substantially liquid form may also refer to gelatinous substances, e.g. plant protection products.

[0004] Basically, the present invention concerns the technical field of drones, also referred to as UAVs (Unmanned Aerial Vehicles).

[0005] It is known in the art that drones or unmanned aerial vehicles may be either fully automated, e.g. made to follow a flight profile pre-programmed in their control unit, or controlled remotely by an operator from a fixed or mobile station.

[0006] The earliest designs of unmanned aerial vehicles date back to the twenties of the past century, but only microtechnologies and nanotechnologies first developed in the nineties made it possible to experiment the use of such vehicles for military missions, particularly to avoid risks for humans.

[0007] The use of unmanned aerial vehicles for civil applications has recently gained much interest as well, also because of the improved reliability and reduced cost of such vehicles. By exploiting the possibility of installing various types of sensors aboard drones, many civil applications have been developed, ranging from environmental monitoring by means of remote survey sensors (e.g. for monitoring the territory after the occurrence of natural phenomena of different kinds, or for checking critical infrastructures) to collection of data from sensors distributed on the territory.

[0008] It is also known in the art that the distribution of substances in substantially liquid form, such as fertilizers, insecticides, and the like, on plants, cultivations and soils is a common practice aimed at protecting crops from harmful parasites and diseases and / or restoring, preserving or improving the fertility of land.

[0009] Such liquid products or substances can be distributed manually by terrestrial or aerial vehicles; for instance, on large stretches of land, whether already cultivated or still to be cultivated, liquid products or substances can undoubtedly be distributed more quickly by using an aerial vehicle. In this regard, it can be observed that traditional aircraft, while they can distribute large amounts of liquid substances, suffer from the drawback that they cannot ensure a precise distribution of such substances, especially due to the fact that they must necessarily distribute said liquid substances while flying high over the ground and the surface intended to receive the substance.

[0010] As a consequence, the use of drones for distributing a liquid substance on land has made it possible to obtain an accurate distribution of said liquid substance, in particular because drones (or unmanned aerial vehicles, UAV) can fly much lower than any other aircraft. In such a context, the fact that a drone can fly close to cultivated land results in the right amount of liquid substance being distributed in the desired places, thus ensuring better and more uniform coverage of an area (e.g. also in compliance with specific provisions in force in a given area) and considerably reducing any windage effects, i.e. out-of-field dispersion of product.

[0011] In addition to this, distributing a liquid substance by means of a drone represents the ideal solution wherever the conformation of the scenario and / or the conditions of the soil make it difficult or even impossible, without incurring in very high costs, to execute traditional automated or manual treatments.

[0012] Distributing a liquid substance by means of a drone may also be cost-effective in many environmental, industrial, etc. applications, i.e. wherever liquids need to be distributed in complex scenarios (e.g. distribution on vertical walls).

[0013] The drones currently known in the art for the distribution of a liquid substance are so designed as to comprise a distribution system comprising a tank adapted to contain said liquid substance and a spraying system comprising at least one nozzle for spraying the liquid substance contained in the tank.

[0014] In this frame, one of the most important drawbacks of the drones currently known in the art lies in the fact that they are much affected by oscillatory motion, also known as sloshing, of the liquid substance in the tank, such phenomenon being such as to lead to disturbances impairing the stability of the drone, such disturbances being non-negligible particularly in applications where a liquid substance needs to be distributed or sprayed with high precision (e.g. precision agriculture).

[0015] In this frame, it is the main object of the present invention to provide a drone for the distribution of a liquid substance, in particular for precision agriculture, which has been so conceived as to overcome the drawbacks of prior-art drones.

[0016] In particular, the present invention aims at providing a drone for the distribution of a liquid substance, in particular for precision agriculture, which has been so conceived as to eliminate, or at least considerably reduce, the undesired phenomenon of the oscillatory motion, also known as sloshing, of the liquid substance in the tank.

[0017] Therefore, it is one object of the present invention to provide a drone which is so constructed as to make negligible any disturbances that might adversely affect the drone’s stability, particularly the sloshing of the liquid.

[0018] It is another object of the present invention to provide a drone which can be used in such a way as to ensure an optimal distribution of a liquid substance, particularly in the field of precision agriculture.

[0019] Further objects, features and advantages of the present invention will become apparent in light of the following detailed description and of the annexed drawings, which are provided herein merely by way of non-limiting explanatory example, wherein:

[0020] - Fig. 1 is a perspective view of a drone for the distribution of a liquid substance, in particular for precision agriculture, according to the present invention;

[0021] - Fig. 2A and Fig. 2B show, respectively, a perspective view and a plan view of some components of a system for the distribution of a liquid substance of the drone according to the present invention;

[0022] - Fig. 3 A and Fig. 3B show, respectively, a perspective view and a plan view of a tank of the distribution system according to the present invention;

[0023] - Fig. 4A and Fig. 4B show, respectively, a perspective view and a plan view of a container included in the distribution system according to the present invention;

[0024] - Fig. 5 is a block diagram of a stabilization system of the drone according to the present invention, in particular preventing any sloshing of the liquid substance contained in the tank.

[0025] Referring now to the annexed drawings, in Fig. 1 reference numeral 1 designates as a whole a drone for the distribution of a liquid substance, in particular for precision agriculture, according to the present invention.

[0026] The drone 1 comprises a central body or “cell” 2, with which at least one rotor 3 is associated. Said central body 2 is preferably so designed as to comprise a frame representing the load-bearing structure of the drone 1, which may be made of wood, plastic, aluminium, carbon, etc. As is known, the composition of the frame is important to determine the strength and the weight of the drone 1, and hence the flight range thereof; likewise, the size of the frame, and hence its diameter, affects the flight performance of the drone 1, since a large diameter will ensure better flight stability, but will result in heavier weight and higher energy consumption. In one embodiment, the frame of the drone 1 according to the present invention may comprise a pair of plates (e.g. made of carbon, bakelite, or other light and resistant materials) facing and connected to each other in a manner substantially known in the art. In addition, the central body 2 of the drone 1 may be made to comprise a structure or bodywork (not shown in Fig. 1) adapted to cover, at least partly, said frame; also said bodywork may be made of materials known in the art, e.g. plastic materials.

[0027] It should be noted that particular reference will be made in the present description to a multirotor drone 1 (like, for example, the one shown in Fig. 1), i.e. a drone of the type comprising a plurality of rotors 3 associated with the central body 2, in particular through a plurality of arms 4 and wherein each rotor 3 is located at a distal end of a respective arm 4; it is however clear that the teachings of the present invention can also be implemented in a drone 1 of a different type, e.g. a drone Irealized in such a way to comprise at least two rotors 3 per arm 4.

[0028] The embodiment shown in Fig. 1 presents a drone 1 of the type equipped with six rotors

[0029] 3, wherein each rotor 3 is associated with a respective motor (for example, included in the driving means 21 shown in Fig. 5), in particular an electric motor and, preferably, of the brushless type; therefore, in this embodiment the drone 1 comprises a plurality of arms 4 extending from the central body 2 (in particular, extending substantially horizontal from said central body 2 when the drone 1 is in an operating condition, i.e. a flight condition) and supporting the rotors 3 mounted thereto. In particular, the drone 1 shown in Fig. 1 has one of the most common structures in the art (also referred to as “hexacopter” or “hexa”), since it comprises six rotors 3 and six associated arms 4. Other known configurations are nevertheless possible as well: for example, the drone 1 may be of the type that comprises four rotors 3 and four associated arms 4 (referred to in the art as “quadcopter” or “quad”) or of a type comprising a different number of rotors 3 and arms

[0030] 4.

[0031] As far as the arms 4 of the drone 1 are concerned, they may be either of a foldable type or of a rigid type. In this regard, arms 4 of a foldable type make transporting the drone 1 easier, but also make it more subject to damage because the connection joints of the various portions of each arm (or those connecting the arm 4 to the central body 2) may break or deform over time and use; as far as arms 4 of a rigid type are concerned, they are less comfortable for transportation, but are much sturdier and cannot be easily damaged in case of an accidental fall or collision caused by a risky manoeuvre or a fortuitous external event.

[0032] The drone 1 according to the present invention may also comprise support members 5 adapted to bear its weight when it is resting on a surface, wherein said support members 5 may optionally be able to damp the impact in case of hard landing of the drone 1.

[0033] The drone 1 according to the present invention further comprises a distribution system (designated as a whole by reference numeral 10 in Fig. 1) for distributing said liquid substance, wherein the distribution system 10 comprises a tank 11, adapted to contain said liquid substance, and at least one nozzle 10A for distributing or spraying the liquid substance contained in the tank 11, and wherein said tank 11 is associated with the central body 2 of the drone 1. The distribution system 10 according to the present invention comprises at least one pipe 10B adapted to connect said at least one nozzle 10A to the tank 11 and to allow the liquid to flow from the tank 11 to the nozzle 10A.

[0034] Preferably, said at least one nozzle 10A is located in proximity to said at least one rotor 3, so that the rotation of the rotor 3 can improve the dispersion and distribution of the liquid substance; it is however clear that said at least one nozzle 10A may also be positioned elsewhere. Also, in the embodiment shown in Fig. 1 there are two nozzles 10A positioned on two respective arms 4 of the drone 1; it is however clear that the number of nozzles 10A may be greater than two; in particular, the drone 1 may be made to comprise a number of nozzles 10A matching the number of rotors 3 and / or the number of arms 4 of the drone 1.

[0035] As is particularly visible in Figures 2A to 3B, in accordance with the present invention said tank 11 comprises a main body 11A with a polygonal geometry that provides an axisymmetric property, wherein said main body 11 A has symmetry about a vertical axis centred in the centre of mass of the tank 11 (said vertical axis and centre of mass are not shown in the annexed drawings).

[0036] It is therefore apparent that the main body 11 A of said tank 11 is shaped substantially as a hollow prism with a polygonal base, i.e. a polygonal-base prism with a through cavity (such cavity being adapted to contain the liquid, i.e. inside the tank 11).

[0037] In one embodiment, the main body 11 A of the tank 11 comprises a number of sides 1 IL corresponding to the number of rotors 3 of the drone 1.

[0038] In accordance with a preferred embodiment (shown in the accompanying drawings, and particularly visible in Fig. 3B), the drone 1 comprises at least six rotors 3, and said main body 11 A of the tank 11 comprises at least six sides 1 IL (i.e. the number of rotors 3 and the number of sides 1 IL are greater than or equal to six, which can also be represented as follows: number of rotors 3 > 6, number of sides 1 IL > 6). In this context, the main body 11 A of the tank 11 preferably comprises six sides 1 IL, thus being shaped as a hollow prism with a hexagonal base; this embodiment should be preferred when the drone 1 is equipped with six rotors 3, in particular wherein each rotor 3 is supported by a respective arm 4 extending from the central body 2 at (and / or over) an edge of the main body 11 A of the tank 11 (as shown in Fig. 1).

[0039] Furthermore, the tank 11 according to the present invention comprises a base 1 IB having a substantially frustopyramidal shape, in particular for channelling the liquid contained in the tank 11 towards a liquid extraction point (not shown) formed in a minor base 1 IBM of said substantially frustopyramidal base 1 IB. As can be observed in Figures 2B to 3B, the substantially frustopyramidal base 1 IB extends in a direction opposite to that of the main body 11 A of the tank 11.

[0040] In particular, as is particularly visible in figure 3B, said base 1 IB having a substantially frustopyramidal shape is so constructed as to comprise a number of second sides 11BL corresponding to the number of sides 11L of the main body 11 A, i.e. at least six second sides 11BL (in the above-described preferred embodiment).

[0041] The particular conformation of the tank 11 according to the present invention makes it possible to reduce the phenomenon of the sloshing of the fluid contained in said tank 11, which causes disturbances impairing the stability of the drone, such disturbances being non-negligible particularly when precision spraying is involved.

[0042] The tank 11 according to the present invention comprises at least one filler neck 11C for introducing the liquid into said tank 11.

[0043] In a preferred embodiment, said at least one filler neck 11C comprises a first tract extending substantially horizontally from one side 1 IL of the tank 11 and a second tract extending substantially vertically from the first tract; such a conformation of the filler neck 11C facilitates the operation of pouring the liquid into the tank 11, even with the distribution system 10 installed on the drone 1.

[0044] It should also be noted that the filler neck 11C is preferably so constructed as to comprise a filter (not shown in the drawings), in particular of a removable type, adapted to remove any impurities from the liquid to be introduced into the tank 11.

[0045] As can be seen in Figures 3 A and 3B, the distribution system 10 according to the present invention comprises at least one plate 13 positioned vertically within the tank 11 and comprising a plurality of holes 13F to allow the liquid in the tank 11 to move while at the same time reducing the sloshing of the fluid contained in said tank 11.

[0046] In this respect, it should be noted that the diameters and positions of the holes 13F have been defined on the basis of fluid-dynamic analyses and simulations conducted to evaluate their effect on the dynamics of the liquid contained in the tank 11.

[0047] In particular, the plate 13 is positioned in the tank 11 in such a way that between a bottom edge of the plate 13 and the base 11B of the tank 11 there is at least one space or gap allowing passage of the liquid, and that lateral edges of the plate 13 are in contact with the body 11 A of the tank 11.

[0048] In the embodiment shown in Fig. 3B, it can be observed that the distribution system 10 comprises two plates 13 positioned within the tank 11 in such a way as to be substantially perpendicular to each other; it is however clear that the number of plates 13 and their positions within the tank 11 may differ from those shown in the annexed drawings.

[0049] In one embodiment, the distribution system 10 according to the present invention comprises a container 12, in particular a sealed one, associated with a top portion of the main body 11 A of the tank 11 (said top portion consisting of that part of the main body 11 A which is opposite the one where the base 1 IB is formed), wherein said container 12 is configured to house (and also insulate and protect) a system for taking and spraying the liquid contained in the tank 11 ; for example, said system for taking and spraying the liquid may comprise at least one access to the tank 11 for taking the liquid contained in said tank 11, at least one pump 12A (note that two pumps 12A are shown in Figures 4A and 4B), at least one pressure regulator (not shown), a battery (not shown), at least one sensor (e.g. second sensor means 22B and / or additional sensor means 22C that will be described below with reference to Fig. 5).

[0050] Preferably, said container 12 comprises a lateral wall (12L) shaped in a way substantially matching the main body 11 A of the tank 11, in particular said lateral wall 12L comprising a number of faces 12F corresponding to the number of sides 1 IL of the main body 11 A, and wherein each face 12F is positioned over a respective side 1 IL so as to lie in a plane which is substantially parallel to the one in which the respective side 1 IL lies; eventually, each face 12F of the lateral wall 12L is so positioned as to be substantially coplanar with a respective side 1 IL of the main body 11 A.

[0051] The container 12 further comprises a top wall 12S that permits closing said container 12, in particular in an airtight manner, wherein said top wall 12S comprises coupling means (not shown in the drawings, preferably of the quick-coupling type) for fastening the assembly consisting of the tank 11 and the container 12 to the central body 2 of the drone 1.

[0052] The distribution system 10 according to the present invention further comprises fastening means 14 (as clearly visible in Fig. 4 A, where said fastening means 14 are shown to include, by way of example, some threaded bars and respective bolts) which engage with the tank 11 and the container 12 to ensure a firm connection of such components. Clearly, said fastening means 14 may differ from those shown in the annexed drawings.

[0053] Figure 5 shows that the drone 1 according to the present invention comprises a control system (designated as a whole by reference number 20) for managing the drone 1 and for effecting an automatic stabilization of the flight of the drone 1 , in particular for preventing any sloshing of the liquid substance within the tank 11 during the flight of the drone 1.

[0054] The control system 20 comprises driving means 21 operatively connected to a plurality of rotors 3 of the drone 1 in such a way as to drive each rotor 3 independently (i.e. each rotor 3 is driven independently of the other rotors 3), first sensor means 22 A operatively connected to the tank 11 to detect the level of the liquid in said tank 11, second sensor means 22B operatively connected to the drone 1 to detect the inertia thereof, and a control unit 23 operatively connected to the driving means 21, to the first sensor means 22 A, and to the second sensor means 22B.

[0055] The driving means 21 may comprise, for example, a plurality of motors, in particular of the electric type, wherein each motor is operatively connected to a respective rotor 3.

[0056] The first sensor means 22A may comprise, for example, at least one level sensor positioned inside the tank 11, and the second sensor means 22B may comprise, for example, at least one inertial sensor associated with the drone 1. Preferably, said at least one inertial sensor is positioned inside the container 12; it should be noted that also said control unit 23 can be housed inside the container 12.

[0057] The control system 20 may further comprise additional sensor means 22C operatively connected to the drone 1 and to the control unit 23 to supply said control unit 23 with additional signals representative of an operating condition of the drone 1 according to the present invention. For example, said additional sensor means 22C may be adapted to acquire at least one signal representative of external disturbances, like for example the wind, which may affect the stability of the drone 1, or at least one signal representative of mechanical vibrations of the drone 1, or at least one signal representative of the speed of flight of the drone 1, wherein said additional sensor means 22C may comprise, for example, at least one of the following sensors: an anemometer, a piezoelectric sensor, an acoustic sensor, a capacitive sensor, an inductive sensor, and a resistive sensor.

[0058] The signals acquired by the sensor means 22A, 22B, 22C may be either analogue or digital, and can be transmitted from the sensor means 22A, 22B, 22C to the control unit 23 via a data / power bus (generically designated by reference numeral 200 in Fig. 5) adapted to operatively connect the control unit 23 to the sensor means 22 A, 22B, 22C.

[0059] In this context, the control unit 23 is configured to generate control signals for controlling the driving means 21 in order to drive each rotor 3 independently as a function of the signals received from the first sensor means 22 A and / or from the second sensor means 22B (and / or, eventually, from said additional sensor means 22C), so as to effect an automatic stabilization of the drone 1 during the flight operations (in particular to prevent or limit the sloshing of the liquid substance within the tank 11 during the flight operations of the drone 1).

[0060] Basically, said sensor means 22A, 22B, 22C allow the control unit 23 to perform an estimate of the disturbances and their effects along a certain timeline, and allow the implementation of a control unit 23 based on a predictive approach (for example, the Model Predictive Control), which offers higher performance than traditional control approaches.

[0061] In one embodiment of the invention, the drone 1 may comprise a management unit (designated as a whole by reference numeral 30 in Fig. 5) adapted to manage the flight, in particular the autonomous flight, of the drone 1.

[0062] The management unit 30 can be used by a user, for example, in order to set a path to be followed by the drone 1 and to allow said user to visualize such path.

[0063] The management unit 30 may comprise, for example, a memory 31, an interface module 32, an input / output module 33 and a processor 34 operatively connected to one another; the management unit 30 may be, for example, a computer, a smartphone, a tablet, and so on.

[0064] The memory 31 of the management unit 30 is adapted to internally store information about the autonomous flight of the drone 1; such information may comprise, for example, data received from the control unit 23, like for example values indicating the position, speed and operating state of the drone 1, maps of at least a portion of the environment where the drone 1 is operating, and so forth.

[0065] Said information are sent and / or received by the management unit 30 in communication with the control unit 23 via the interface module 32, which may be, for example, a USB, WiFi, Bluetooth, GSM, LTE, 5G, CANBUS, Ethernet, etc. interface. For example, in the present embodiment of the invention, the control unit 23 of the drone 1 may be connected to the interface module 32 of the management unit 30 by means of a GSM, LTE or 5G interface.

[0066] The input / output module 33 allows the user to interact with the management unit 30. In this respect, the input / output module 33 may comprise output and input means, e.g. a display and an alphanumeric keyboard, respectively, or, alternatively, a touchscreen displaying an alphanumeric keyboard and interactive symbols.

[0067] The processor 34 of the management unit 30 is adapted to process the information contained in the memory 31 of the management unit 30, for example in order to generate one or more paths for the drone 1. The processor 34 of the management unit 30 is adapted to display, via said input / output module 33, the generated maps and / or the operating state of the control unit 23.

[0068] The management unit 30 may be implemented, for example, as a computer program product comprising portions of software code, which can be loaded into a memory of a smartphone, a tablet or a computer equipped with interface means such as, for example, a USB, WiFi, Bluetooth, GSM, LTE, 5G, CANBUS, Ethernet interface, and so on.

[0069] In one embodiment of the invention, the management unit 30 may be a user’ s smartphone, which is connected to the control unit 23 of the drone 1 through the interface module 32, in particular wherein the control unit 23 is adapted to automatically move the drone 1, also as a function of the information exchanged with the management unit 30.

[0070] In a further embodiment of the invention, the control unit 23 is adapted to automatically move the drone 1 as a function of information recorded therein, in particular stored in a memory 23 A of said control unit 23.

[0071] In this regard, it should be noted that a precise and accurate planning of the trajectories to be followed during the spraying operations, in particular in precision agriculture, is very important to limit windage effects, i.e. to prevent the product from being sprayed on undesired areas.

[0072] The drone 1 according to the present invention further comprises power supply means (not shown in the annexed drawings), which supply energy to the driving means 21, the control unit 23 and the sensor means 22A, 22B, 22C. Said power supply means may comprise, for example, one or more lithium batteries, nickel -cadmium batteries, or the like, and may comprise devices for charging such batteries, such as for example inverters or power supply units. For example, the power supply means can supply power to the driving means 21, control unit 23 and sensor means 22A, 22B, 22C via the data / power bus 200.

[0073] Preferably, said power supply means are housed in the container 12.

[0074] The features of the drone 1 according to the present invention, as well as the advantages thereof, are apparent from the above description.

[0075] Indeed, the provisions of the present invention make it possible to overcome the drawbacks of prior-art drones by providing a drone 1 so conceived as to comprise a tank 11 having such a conformation that reduces the phenomenon of the sloshing of the fluid contained in said tank 11.

[0076] Consequently, another advantage of the solution of the present invention lies in the fact that the drone 1 is so conceived as to eliminate, or anyway reduce, any disturbances that might impair the stability of the drone 1, which disturbances are particularly non- negligible during precision spraying operations.

[0077] In this regard, it must be pointed out that the peculiar provisions pertaining to said at least one plate 13, as well as those pertaining to the control system 20 according to the present invention, strongly contribute to reducing the phenomenon of the sloshing of the fluid contained in said tank 11.

[0078] A further advantage of the drone 1 according to the present invention lies in the fact that the components of the distribution system 10 and / or the components of a system for taking and spraying said liquid are adequately housed, insulated and protected by the container 12, which substantially acts also as a cover for the tank 11.

[0079] Therefore, the provisions of the present invention make it possible to obtain a drone 1 which can be used in such a way as to ensure an optimal distribution of a liquid substance, particularly in the field of precision agriculture.

[0080] The drone 1 and the associated tank 10 and control system 20 described herein by way of example may be subject to many possible variations without however departing from the novelty spirit of the inventive idea; it is also clear that in the practical implementation of the invention the illustrated details may have different shapes or be replaced with other technically equivalent elements.

[0081] It can therefore be easily understood that the present invention is not limited to the above- described drone 1 and the associated tank 10 and control system 20, but may be subject to many modifications, improvements or replacements of equivalent parts and elements without departing from the inventive idea, as clearly specified in the following claims.

Claims

CLAIMS1. Drone (1) for the distribution of a liquid substance, in particular for precision agriculture, comprising:- a central body (2), with which at least one rotor (3) is associated;- a distribution system (10) for distributing said liquid substance, wherein the distribution system (10) comprises a tank (11), adapted to contain said liquid substance, and at least one nozzle (10A) for distributing or spraying the liquid substance contained in the tank (11), and wherein said tank (11) is associated with the central body (2) of the drone (1), said drone (1) being characterized in that said tank (11) comprises a main body (11 A) with a polygonal geometry that provides an axisymmetric property, wherein said main body (11 A) has symmetry about a vertical axis centred in the centre of mass of the tank (11), and wherein said main body (11 A) of the tank (11) is shaped substantially as a hollow prism with a polygonal base.

2. Drone (1) according to claim 1, characterized in that said drone (1) comprises a plurality of rotors (3), wherein said main body (11 A) of the tank (11) comprises a number of sides (1 IL) corresponding to the number of rotors (3) of the drone (1).

3. Drone (1) according to one or more of the preceding claims, characterized in that said drone (1) comprises at least six rotors (3) and said main body (11 A) of the tank (11) comprises at least six sides (1 IL).

4. Drone (1) according to one or more of the preceding claims, characterized in that the tank (11) comprises a base (11B) having a substantially frustopyramidal shape and adapted to channel the liquid contained in the tank (11) towards a liquid extraction point formed in a minor base (1 IBM) of said base (1 IB) having a substantially frustopyramidal shape.

5. Drone (1) according to claim 4, characterized in that said base (11B) having a substantially frustopyramidal shape is so constructed as to comprise a number of second sides (11BL) corresponding to the number of sides (1 IL) of the main body (11 A).

6. Drone (1) according to one or more of the preceding claims, characterized in that said tank (11) comprises at least one filler neck (11C) for introducing the liquid into said tank (H).

7. Drone (1) according to one or more of the preceding claims, characterized in that said at least one filler neck (11C) comprises a first tract extending substantially horizontallyfrom one side (1 IL) of the tank (11) and a second tract extending substantially vertically from the first tract.

8. Drone (1) according to one or more of the preceding claims, characterized in that said distribution system (10) comprises at least one plate (13) positioned vertically within the tank (11) and comprising a plurality of holes (13F) to allow the liquid in the tank (11) to move while at the same time reducing the sloshing of the fluid contained in said tank (11).

9. Drone (1) according to claim 8, characterized in that said at least one plate (13) is positioned in the tank (11) in such a way that between a bottom edge of the plate (13) and the base (1 IB) of the tank (11) there is at least one space or gap allowing passage of the liquid, and that lateral edges of the plate (13) are in contact with the body (11 A) of the tank (11).

10. Drone (1) according to one or more of the preceding claims 8 and 9, characterized in that said distribution system (10) comprises two plates (13) positioned within the tank (11) in such a way as to be substantially perpendicular to each other.

11. Drone (1) according to one or more of the preceding claims, characterized in that said distribution system (10) comprises a container (12), in particular a sealed one, associated with a top portion of the body (11 A) of the tank (11), wherein said container (12) is configured to house a system for taking and spraying the liquid contained in the tank (11).

12. Drone (1) according to claim 11, characterized in that said container (12) comprises a lateral wall (12L) shaped in a way substantially matching the main body (11 A) of the tank (11), in particular said lateral wall (12L) comprising a number of faces (12F) corresponding to the number of sides (11L) of the main body (HA), and wherein each face (12F) is positioned over a respective side (HL) so as to lie in a plane which is substantially parallel to the one in which the respective side (1 IL) lies.

13. Drone (1) according to one or more of claims 11 and 12, characterized in that said container (12) comprises a top wall (12S) that permits closing said container 12, in particular said top wall (12S) comprising coupling means for fastening the assembly consisting of the tank (11) and the container (12) to the central body (2) of the drone (1).

14. Drone (1) according to one or more of the preceding claims, characterized in that it comprises a control system (20) for managing the drone (1) and for effecting an automatic stabilization of the flight of the drone (1), in particular for preventing any sloshing of the liquid substance within the tank (11) during the flight of the drone (1), wherein said control system (20) comprises:- driving means (21) operatively connected to a plurality of rotors (3) of the drone (1) in such a way as to drive each rotor (3) independently,- first sensor means (22 A) operatively connected to the tank (11) to detect the level of the liquid in said tank (11), - second sensor means (22B) operatively connected to the drone (1) to detect the inertia thereof, and- a control unit (23) operatively connected to the driving means (21), to the first sensor means (22A), and to the second sensor means (22B).

15. Drone (1) according to claim 14, characterized in that said control unit (23) is configured to generate control signals for controlling the driving means (21) to drive each rotor (3) independently as a function of the signals received from the first sensor means (22A) and / or from the second sensor means (22B), so as to effect an automatic stabilization of the drone (1) during the flight operations, in particular to prevent or limit the sloshing of the liquid substance within the tank (11) during said flight operations.

16. Tank (11) adapted to be associated with a drone (1) according to one or more of claims 1 to 15.

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