Patent ID: 12218621

In these figures, references identical from one figure to another designate identical or analogous elements. For reasons of clarity, the elements shown are not to scale, unless explicitly stated otherwise.

DETAILED DESCRIPTION

The present disclosure relates to a system for generating electrical energy that may be used for instance at an agricultural site, or any site where temporary generation of electrical energy may be required.

The system comprises a plurality of mobile robots, which may be e.g. autonomous or remotely controlled. Since these robots are mobile, they may be e.g. stored in a parking area when no electrical energy is to be produced and moved on-demand to a target area when electrical energy is to be produced.

The mobile robots are mainly of two types:a producing robot is used mainly to generate electrical energy; anda collecting robot is used mainly to collect electrical energy generated by a plurality of producing robots coupled to said collecting robot, and to output it to an output port from which the electrical energy can be used by another equipment.

Typically, when required, at least one collecting robot and a plurality of producing robots travel to a target area. Once positioned in the target area, couplings are established between the mobile robots in order to form an array of coupled mobile robots, a “coupling” between two mobile robots enabling electrical energy transfer from one mobile robot to the other.

FIG.1represents schematically an exemplary embodiment of a collecting robot10. As can be seen inFIG.1, the collecting robot10comprises displacement means14adapted to move the collecting robot10e.g. from a parking area to a target area. The displacement means14may be of any type known to the skilled person, and the movement of the collecting robot10may be terrestrial and/or aerial. For instance, the collecting robot10may be an unmanned terrestrial vehicle, UTV, and/or an unmanned aerial vehicle, UAV. Preferably, the displacement means14are electrical, and comprise e.g. one or more electrical motors for rotating wheels and/or propellers.

Also, the collecting robot10comprises at least one input port11adapted for coupling with a producing robot20for receiving electrical energy thereof. Preferably, the collecting robot10comprises a plurality of input ports11for e.g. coupling simultaneously with a plurality of producing robots20and/or for enabling different types of couplings with producing robots20(e.g. mechanical coupling, wireless coupling, etc.) and/or for increasing geometrical coupling flexibility by providing multiple different possible positions for a producing robot20to be coupled with the collecting robot10.

The collecting robot10comprises also an output port12for outputting electrical energy received from each producing robot20coupled with the collecting robot10. As discussed above, the purpose of the collecting robot10is mainly to centralize electrical energy received from a plurality of producing robots20. Accordingly, the collecting robot10may comprise a single output port12. However, the collecting robot10may also, in other examples, comprise a plurality of output ports12for supplying electrical energy to a plurality of equipment and/or for enabling different types of connections with the equipment that is to be supplied with electrical energy (e.g. mechanical connection, wireless connection, etc.). In preferred embodiments, the collecting robot10may be a tethered mobile robot in which the output port12is located at an end of a cable. Preferably, a tethered collecting robot10comprises a cable reel, for e.g. enabling storing the cable in a compact manner when not in use.

As discussed above, the purpose of the collecting robot10is mainly to centralize electrical energy received from a plurality of producing robots20. Accordingly, the collecting robot10may be devoid of electrical energy generating means. However, in preferred embodiments, the collecting robot10may comprise also electrical generating means, at least for its own electrical energy consumption, and preferably for producing electrical energy to be outputted on its output port12. In the preferred embodiment represented byFIG.1, the collecting robot10comprises a photovoltaic, PV, generator13. The PV generator13may comprise a rigid PV surface, a PV flexible surface, etc., or any combination thereof. In some embodiments, the PV surface of the PV generator13may foldable/un-foldable.

The PV surface of the PV generator13may be fixed with respect to a main body of the collecting robot10.

However, in preferred embodiments, the collecting robot10may comprise means (not represented in the figures) for modifying the inclination of the PV surface with respect to the main body of the collecting robot10. Such inclination modifying means may be any suitable means known to the skilled person and are preferably such they enable tilting the PV surface with respect to the main body with at least one degree of freedom, or preferably at least two degrees of freedom. For instance, modifying the inclination of the PV surface may be used to optimize the sunshine on the PV surface (e.g. by maintaining the PV surface substantially orthogonal to the sun rays) and/or in order to modify the shadowing made by the collecting robot10, etc., without moving the collecting robot10. For instance, the inclination modifying means may be controlled in order to modulate the shadowing made by the PV surface on e.g. crop below the collecting robot10, while generating electrical energy. The inclination of the PV surface may also be dynamically adjusted as a compromise between electrical energy generation needs and shadow generation needs, or it is possible to define time intervals during which electrical energy generation is a priority and is to be maximized and other time intervals during which shadow generation is a priority and is to be optimized (maximized or minimized), etc.

As illustrated byFIG.1, the collecting robot10comprises an electrical energy collector module15configured to collect the electrical energy received on any input port11(directly or via the PV generator13, seeFIG.4) and to provide the electrical energy collected on the output port12. If the collecting robot10comprises also electrical energy generating means, such as a PV generator13, then the electrical energy collector module15is preferably also configured to collect the electrical energy generated locally by the collecting robot10. In preferred embodiments, the electrical energy collector module15may comprise an electrical energy storage module (not represented in the figures), i.e. an electrical energy accumulator, for storing collected electrical energy. For instance, electrical energy may be stored if the level of electrical energy collected is higher than the level of electrical energy needed by any separate equipment connected to the output port12of the collecting robot10. The electrical energy stored may be recovered and outputted on the output port12when e.g. the level of electrical energy collected in real-time becomes lower than the level of electrical energy needed (e.g. when the sun is temporally hidden by clouds, when inclination modifying means are used to optimize shadow generation, etc.).

As represented byFIG.1, the collecting robot10comprises also a control module16for controlling the displacement means14, and more generally for controlling the collecting robot10. For example, the control module16comprises one or more processors and storage means (any type of computer readable storage medium) in which a computer program product is stored, in the form of a set of program-code instructions to be executed in order to control the collecting robot10. Alternatively, or in combination thereof, the control module16can comprise one or more programmable logic circuits (FPGA, PLD, etc.), and/or one or more specialized integrated circuits (ASIC), etc., adapted for controlling the collecting robot10. In other words, the control module16comprises a set of means configured by software (specific computer program product) and/or by hardware (processor, FPGA, PLD, ASIC, etc.) for controlling the collecting robot10.

In preferred embodiments, and as illustrated byFIG.1, the collecting robot10may comprise a communication module17, for communicating data with other devices. Preferably, the communication module17is configured to exchange data according to at least one wireless communication protocol (WiFi®, Bluetooth®, 4G, 5G, etc. or any proprietary wireless communication protocol). In addition, or alternatively, the communication module17may be configured to exchange data according to at least one wired communication protocol. For instance, the communication module17may be used to receive data representative of an array configuration, such as a target position where the collecting robot10has to move, and any information necessary for enabling the collecting robot10to move to the target area. In case the collecting robot10moves in an autonomous manner to the target area, this data may be received before departing to the target area. If the collecting robot10is remotely control during its journey to the target area, this data may be continuously received during the journey, until the collecting robot10reaches the target area, etc.

In preferred embodiments, the collecting robot10may also comprise one or more sensors (not represented in the figures). For instance, the collecting robot10may comprise one or more navigation sensors (e.g. GPS sensor, etc.) for enabling the collecting robot10to reach the target area, one or more imaging sensors (e.g. camera, etc.) for e.g. acquiring information on the configuration of the target area, etc.

FIG.2represents schematically an exemplary embodiment of a producing robot20. As can be seen inFIG.2, the producing robot20comprises displacement means24adapted to move the producing robot e.g. from a parking area to a target area. The displacement means24may be of any type known to the skilled person, as discussed above for the collecting robot10. For instance, the producing robot20may be an UTV and/or an UAV.

As discussed above, the purpose of a producing robot20is mainly to generate electrical energy. Accordingly, the producing robot20comprises electrical energy generating means, preferably a PV generator23. The PV generator23of a producing robot20may have the same properties as those discussed above for the collecting robot10. Also, in preferred embodiments, the producing robot20may also comprise means (not represented in the figures) for modifying the inclination of the PV surface with respect to a main body of the producing robot20, as discussed for the collecting robot10.

Also, the producing robot20comprises at least one input port21adapted for coupling with another producing robot20, for receiving electrical energy thereof. Preferably, the producing robot20comprises a plurality of input ports21for e.g. coupling simultaneously with a plurality of producing robots and/or for enabling different types of couplings with producing robots20, and/or for increasing geometrical coupling flexibility by providing multiple different possible positions in which two mobile robots can be coupled together.

The producing robot20comprises also at least one output port22for outputting electrical energy generated by the PV generator23of the producing robot20and electrical energy received from each other producing robot20it is coupled with. Preferably, the producing robot20comprises a plurality of output ports22for coupling simultaneously with a plurality of producing robots20and/or collecting robots10and/or for enabling different types of couplings, and/or for increasing geometrical coupling flexibility by providing multiple different possible positions in which two mobile robots can be coupled together.

As represented byFIG.2, the collecting robot10comprises also a control module26for controlling the displacement means24, and more generally for controlling the producing robot20. The control module26of a producing robot20may have the same properties as those discussed above for the collecting robot10.

In preferred embodiments, and as illustrated byFIG.2, the producing robot20may comprise a communication module27, for communicating data with other devices. The communication module27of a producing robot20may have the same properties as those discussed above for the collecting robot10.

In some embodiments, and as illustrated byFIG.2, the producing robot20may comprise an electrical energy collector module25configured to collect the electrical energy received on any input port21and generated by its own PV generator23, and to provide the electrical energy collected on at least one output port22. When present, the electrical energy collector module25of a producing robot20may have the same properties as those discussed above for the collecting robot10. When present, the electrical energy collector module25may also comprise, in preferred embodiments, an electrical energy storage module (not represented in the figures) for storing collected electrical energy. However, it is emphasized that, in some embodiments, the producing robot20may be devoid of such an electrical energy collector module25, for instance in the case discussed below where PV cells of different producing robots20are connected, thereby forming a macro PV generator grouping the PV generators of such producing robots20.

In preferred embodiments, the producing robot20may also comprise one or more sensors (not represented in the figures), which may have the same properties as those discussed above for the collecting robot10.

A indicated above, an output port22of a producing robot20may be coupled with an input port21of another producing robot20or with an input port11of a collecting robot10. Typically, the couplings between the mobile robots will be established once the mobile robots have reached the target area, and according to a predetermined array configuration. The coupling between an output port22of a producing robot20with an input port21of another producing robot20or with an input port11of a collecting robot10may be established manually by a human operator or, preferably, automatically by said mobile robots. In the latter case at least, the mobile robots can control their relative positions and orientations to enable the coupling to be established.

The coupling may be wireless, using preferably near-field wireless power transfer technologies such as inductive coupling or capacitive coupling.

Preferably, the coupling is mechanical and may use any suitable electrical connectors to establish an electrical contact between an output port22and an input port11,21. Preferably, the electrical connectors are configured to allow the electrical contact to be established even in case of a slight misalignment between them. Also, the electrical connectors are preferably provided with means which force the electrical contact to be maintained between the output port22and the input port11,21. Such means may be for instance elastic means, such as a spring, and/or magnetic means such as an electro-magnet, etc.

According to a first non-limitative example, the electrical connectors used for establishing an electrical contact between an output port22and an input port11,21may comprise a pair of male/female connectors. For instance, the female connector may be a rigid metal part having a predetermined opening width, while the male connector may be an elastic metal part, such as a folded metal plate, extending between a proximal end and a distal end. The distal end has a width lower than the opening width and the proximal end has a width higher than the opening width. Hence, when the male connector is inserted into the female connector, the proximal end of the male connector is compressed inside the female connector thereby establishing the electrical contact between the female connector and the male connector. According to a second non-limitative example, the electrical connectors may comprise a metal grid or plate, for instance at an input port11,21, and an elastic metal finger that may flex when in contact with the metal grid or plate.

In preferred embodiments, which enable a more precise positioning of the output port22with respect to the input port11,21, said output port22and/or said input port11,21may be carried by a robotic arm (not represented in the figures). For instance, the robotic arm may be controlled autonomously by the mobile robot10,20that carries said robotic arm, or it may be remotely controlled by a human operator.

More generally speaking, any type of electrical connectors enabling an electric contact to be established between an output port22and an input port11,21of different mobile robots may be used in the present disclosure, and the choice of a specific type of electrical connectors corresponds to a specific embodiment of the present disclosure.

FIGS.3and4represent schematically two different examples of coupling between a producing robot20and a collecting robot10comprising a PV generator13. It is emphasized that the examples represented inFIGS.3and4may also apply to the coupling between producing robots20.

In the example represented byFIG.3, both the collecting robot10and the producing robot20comprise an electrical energy collector module15,25. In this example, the producing robot20collects locally the electrical energy generated by its own PV generator23, and possibly electrical energy received from another producing robot20it is coupled with. Both the PV generator23and the input port21of the producing robot20are connected to the electrical energy collector module25. The output of the electrical energy collector module25is connected to the output port22of the producing robot20.

The output port22of the producing robot20is coupled with the input port11of the collecting robot10. As can be seen inFIG.3, the electrical energy collector module15of the collecting robot10is connected to both the PV generator13and any input port11of the collecting robot10. The output of the electrical energy collector module15is connected to the output port12of the collecting robot10.

In part a) ofFIG.3, the sunlight conditions are such that the PV generators13,23generate electrical energy. In part b) ofFIG.3, the sunlight conditions are such that the PV generators13,23do not generate electrical energy anymore (e.g. cloudy weather, night, etc.). However, in this example, the electrical energy collector modules15,25comprise respective electrical energy storage modules, from which previously stored electrical energy may be retrieved and outputted on the output ports12,22.

In the example represented byFIG.4, the producing robot20does not comprise an electrical energy collector module25.FIG.4represents schematically PV cells28,18of the PV generators23,13of the producing robot20and of the collecting robot10. As can be seen inFIG.4, the PV cells28of the producing robot20are connected to the output port22of said producing robot20, and the PV cells18of the collecting robot10are connected to input port11of said collecting robot10. Hence, when the coupling is established, the PV cells28of the producing robot20are connected electrically with the PV cells18of the collecting robot10, thereby forming a macro PV generator composed by the PV generator13of the collecting robot10and the PV generator23of the producing robot20(and possibly other PV generators23of other producing robots20). The electrical energy generated by the macro PV generator is collected directly by the electrical energy collector module15of the collecting robot10. By forming such a macro PV generator grouping the PV generators of the coupled producing robots, the electrical energy transfer losses from each producing robot20to the collecting robot10are minimized. Also, the photovoltaic electrical energy generation is more efficient when connecting together an increased number of PV cells18,28.

Preferably, the PV surfaces of the PV generators13,23have substantially the same shape. For instance, the PV surfaces of the PV generators13,23have a polygonal shape, such as a triangular, square or, preferably, hexagonal shape. In such a case, input ports11,21and output ports12may be arranged at sides of the polygonal shape. Several input ports11,21and several output ports22may be arranged on different sides of the polygonal shape. Preferably, the PV surface of the PV generators13,23define the maximal horizontal dimensions of each mobile robot equipped with a PV generator13,23, in order to facilitate the coupling between output ports22and input ports11,21of different mobile robots.

FIG.5represents schematically a top view of a collecting robot10comprising a PV generator13having a hexagonal PV surface. In the example ofFIG.5, the PV generator13comprises an input port11at each side of the hexagonal PV surface, such that up to six producing robots20can be directly coupled with the collecting robot10. The input ports11are preferably at the sides of the PV surface, but other arrangements are also possible for the input ports11which are not necessarily arranged at the sides of the PV surface. The output port12is preferably not located on a side of the hexagonal PV surface. If the PV surface is arranged in an upper part of the collecting robot10, the output port12may be for instance arranged in a lower part of said collecting robot10. It is emphasized that, while the collecting robot10comprises preferably one input port11per side of the PV surface, it is also possible to have e.g. fewer input ports11.

FIG.6represents schematically a top view of a producing robot20comprising a PV generator23having a hexagonal PV surface. In the example ofFIG.6, the PV generator23comprises three input ports21and three output ports22arranged on opposite sides of the hexagonal PV surface. Preferably, all input ports21and output ports22of the PV generator23are arranged at sides of the PV surface. However, other arrangements are possible for the input ports21and/or the output ports22, which are not necessarily arranged at the sides of the PV surface. It is emphasized that the producing robot20may comprise more input ports21and/or output ports22. For instance, each side of the PV surface may comprise both an input port21and an output port22. Although the input port21and the output port22of a same side may not be used simultaneously, this provides for increased geometrical coupling flexibility since each side of the PV generator23can be used as an input port21or as an output port22. In other examples, the producing robot20may also comprise fewer input ports21and output ports22and may comprise a single input port21and a single output port22arranged on different sides of the PV surface.

By using PV surfaces of polygonal shape, the mobile robots can be coupled in a variety of ways, thereby enabling to compose arrays of coupled mobile robots having different shapes.FIG.7represents schematically examples of possible shapes for an array of coupled mobile robots having hexagonal PV surfaces. InFIG.7, the couplings established are represented by arrows. For instance, part a) ofFIG.7represents a first example of an array having a hexagonal shape, in which the collecting robot10is positioned at the center of the array and has a producing robot20on each side of its PV surface. Part b) ofFIG.7represents a second example of an array having a triangular shape, in which the collecting robot10is positioned at a corner and has a two producing robots20on two adjacent sides of its PV surface. The array comprises also three additional producing robots20that are coupled indirectly with the collecting robot10. Part c) ofFIG.7represents a third example of an array having a linear shape, in which the collecting robot10is positioned at the center of the array has a two producing robots20on two opposed sides of its PV surface. The array comprises also two additional producing robots20that are coupled indirectly with the collecting robot10.

It is emphasized that the embodiments described in reference withFIGS.5to7are possible for both configurations described in reference withFIG.3(each producing robot20has an electrical energy collector module25) andFIG.4(macro PV generator).

FIG.8represents schematically the main steps of an exemplary embodiment of a method80for generating electric energy using a system comprising at least one collecting robot10and a plurality of producing robots20. As can be seen inFIG.8, the method80comprises:a step S80of determining a configuration of an array of coupled mobile robots comprising at least one collecting robot10and a plurality of producing robots, said array configuration defined by a number of mobile robots of the array, respective target positions and target orientations of the mobile robots of the array, and couplings to be established between mobile robots;a step S81of commanding the uncoupled mobile robots to move from their respective current positions to their respective target positions and target orientations of the array configuration;a step S82of coupling the input ports11,21and output ports22, of the mobile robots of the array according to the couplings defined in the array configuration;a step S83of generating electrical energy by the array of coupled mobile robots and outputting generated electrical energy at the output port12of the collecting robot10.

Hence, during step S80, the configuration of the array to be formed at the target area is determined. The determination of the array configuration aims at defining an array that will both:meet the electric energy generation needs at the target area; andcomply with the configuration of the target area configuration.

For instance, the electrical needs are defined as a predetermined target level of electrical energy required and determining an array configuration comprises estimating the level of electrical energy generated by a candidate array configuration and comparing the estimated electrical energy level with the target electrical energy level.

In order to estimate the electrical energy level generated by a candidate array configuration, it is possible to estimate the electrical energy level generated by each PV generator13,23of the candidate array configuration and the electrical energy losses from each PV generator13,23to the output port12of the collecting robot10.

Additionally, or alternatively, the array configuration may be determined based on a predetermined configuration of the target area. Indeed, the target area configuration may set some constraints on the configuration of the array. For instance, the expected weather at the target area will have an impact on the level of electrical energy that can be generated by the array of coupled mobile robots. Hence, the target area configuration may include weather information which includes information on the expected sunshine, at the target area, during one or more scheduled time intervals during which the array of coupled mobile robots is to be formed. Such information on the expected sunshine may be global (i.e. whether clouds are present) and/or local (i.e. whether there are obstacles such as trees and/or buildings that might cast shadows on the array despite the absence of clouds).

According to another example, the target area configuration may include information on the size and/or shape of the target area where the array of coupled mobile robots is to be stationed, and/or the position of the target area. Such information on the target area may be obtained from data acquired by one or more sensors of one or more mobile robots. For instance, a mobile robot may acquire beforehand images of the target area, which images may be used to determine the size and shape of the target area. The position of the mobile robot, for instance measured by a GPS sensor of said mobile robot, may also be used to determine the position of the target area.

According to another example, the target area configuration may include information of the position of at least one extraction point, to which the output of the collecting robot10needs to be connected. In other words, the extraction point is the separate equipment that will use and/or store the electrical energy generated by the array of coupled mobile robots. In particular, the position of the extraction point (i.e. the position in the target area of the equipment that is to be supplied with electrical energy) might set constraints on the position of the collecting robot10within the array of coupled mobile robots.

According to another example, the target area configuration may include information on the scheduled time interval(s) during which the array of coupled mobile robots is to be formed. The scheduled time interval(s) depend on when the electrical energy needs to be generated. However, the scheduled time interval(s) may also depend on the availability of the target area. For instance, there might be time intervals during which the mobile robots cannot station in the target area (e.g. in order let other vehicles access the target area), such that the array may need to be temporarily un-formed (by uncoupling the mobile robots), before being re-formed (by re-coupling the mobile robots). According to another example, there might be time intervals during which the mobile robots may have other tasks to accomplish. For instance, the mobile robots may also be used for temporarily shadowing an area, for instance for protecting crop from the sun when the sunlight is maximum, from heavy rain, from hail, from snow, etc. In that case, it is possible to move all or part of the mobile robots of the array above the area that needs to be shaded. The mobile robots used for shadowing may remain coupled together when moved above the area that is to be shaded, or, alternately, the array may be temporarily un-formed (by uncoupling the mobile robots) for shadowing the crop, before being re-formed (by re-coupling the mobile robots) when shadowing is no longer required.

FIG.9represents schematically examples of target areas90, and corresponding examples of possible array configurations. The couplings between mobile robots are represented by arrows. More specifically, part a) and part b) ofFIG.9represent target areas90with different shapes and possible arrays of coupled mobile robots. It is emphasized that the array configuration is defined by e.g. the respective target positions of the collecting robot10and producing robots20, the respective target orientations of the collecting robot10and producing robots20(to enable the effective coupling between output ports22and input ports11,21) and the couplings to be established between output ports22and input ports11,21. Part c) ofFIG.9represents an array which has the same number of mobile robots with the same target positions/target orientations as in the array represented in part b), but which uses different couplings between the mobile robots. For instance, in part b) ofFIG.9, most of the producing robots20are coupled directly with the collecting robot10and arranged in parallel. In part c) ofFIG.9, only two producing robots20are coupled directly with the collecting robot10, and the array comprises two chains having each four producing robots20arranged in series. The choice of the couplings to be established might depend on the maximum electrical energy than can pass through a producing robot20, on whether high voltage or high current generation is required, on the type(s) of couplings to be established (e.g. configuration ofFIG.3orFIG.4), etc.

For example, we can assume that the system for generating electrical energy comprises a total of NPRproducing robots20and MCRcollecting robots10, each collecting robot10having a PV generator13. For a given candidate array configuration comprising N producing robots20selected among the NPRproducing robots20and one collecting robot10selected among the MCRcollecting robots (i.e. a candidate array configuration comprising (N+1) mobile robots), then the estimated level of electrical energy provided at the output port12of the collecting robot10is for instance given by:

∑i=1N(EPRi-LPRi,j)+(ECRj-LCRj)(1)
expression in which:i is the index of a selected producing robot20, 1≤i≤N;j is the index of the selected collecting robot10;EPRiis the estimated level of electrical energy generated by the PV generator23of the producing robot20of index i;ECRjis the estimated level of electrical energy generated by the PV generator13of the selected collecting robot10of index j;LPRi,jare the estimated electrical energy losses from the PV generator23of the producing robot20of index i to the output port12of the selected collecting robot10of index j;LCRjare the estimated electrical energy losses from the PV generator13of the selected collecting robot10of index j to its own output port12.

EPRiand ECRimay for instance be estimated based on an information on the weather expected at the target area. LPRi,jdepends e.g. on the couplings of the candidate array configuration. For instance, the electrical energy losses will be higher for a producing robot20that is coupled indirectly with the collecting robot10than for a producing robot20that is coupled directly.

If we denote by WTARGET,jthe target electrical energy level at the output port12of the selected collecting robot10of index j, at the target area, then the candidate array configuration may be selected if e.g. the following condition, among others, is satisfied:

∑i=1N(EPRi-LPRi,j)+(ECRj-LCRj)≥WTARGET,j(2)

If we denote by STARGETthe size, in square meters (m2), of the target area, and by SPRiand SCRjthe sizes, in m2, of the projected footprints of respectively the producing robot20of index i and the selected collecting robot10of index j, then a condition with respect to target area that the candidate array configuration may have to satisfy is the following:

∑i=1NSPRi+SCRi≤STARGET(3)

Of course, the shape of the target area may also be considered, in which case the shape of the projected footprint of the candidate array should preferably lie within the shape of the target area (as illustrated inFIG.9).

It should be noted that it is also possible to determine two or more array configurations for the target area, leading to forming two or more arrays of coupled mobile robots in the target area.

For instance, it is possible to evaluate by simulation different possible candidate array configurations, and to select one or more array configurations that satisfy the constraints on e.g. the target electrical energy level, the target area configuration, etc.

In specific embodiments, the step S80of determining the array configuration may comprise also determining an availability information for each mobile robot of the system and selecting the mobile robots of the array based on the availability information of each mobile robot.

For instance, a mobile robot may be considered available if it is not already used (or scheduled to be used) in another array formed in an area different from the present target area.

According to another example, a mobile robot may be considered available if it has an available level of electrical energy, stored e.g. in a battery of said mobile robot, that is enough to move said mobile robot from its current position, in a parking area, to a target position in the target area. For instance, if the available level of electrical energy of a mobile robot is denoted by EAVand if the estimated level of electrical energy required for moving the mobile robot from its current position to the target position is denoted by EMOV, the mobile robot may be considered available if EAV≤EMOV.

According to another example, a mobile robot may be considered available if it is expected to have, after having participated to the array in the target area, a level of electrical energy stored in its battery allowing it to return to the parking area. For instance, if we denote by ESTOthe estimated level of electrical energy that may be generated and stored in the battery of said mobile robot (and not transferred to the output port12of the collecting robot10), while the mobile robot is stationed in the target area, then the mobile robot may be considered available if EAV−EMOV+ESTO≥EMOV.

The step S80of determining the array configuration(s) is for instance implemented by an array controller (not represented in the figures).

For instance, the array controller comprises one or more processors and storage means (any type of computer readable storage medium) in which a computer program product is stored, in the form of a set of program-code instructions to be executed in order to determine array configurations. Alternatively, or in combination thereof, the array controller can comprise one or more programmable logic circuits, and/or one or more specialized integrated circuits, etc., adapted for determining in all or part array configurations. In other words, the array controller comprises a set of means configured by software and/or by hardware for determining array configurations.

For instance, the array controller may comprise or have access to a database storing information, referred to as “operational information”, useful for determining the array configuration(s). Such operational information may include e.g. the target area configuration, estimated levels of electrical energy generated by each PV generator13,23under different sunshine conditions, estimated electric energy losses within each mobile robot and at interfaces between mobile robots, the current positions of the mobile robots, the available electrical energy levels of the mobile robots, etc.

More generally, such a database may include one or more operational information among the following:target area configuration (e.g. weather information for each target area, size and shape of each target area, etc.);information on the mobile robots (e.g. number of collecting robots10, number of producing robots20, number of input ports and output ports of each mobile robot, estimated level of electrical energy generated for each mobile robot, availability information for each mobile robot, size and shape of PV surface of each mobile robot, available type(s) of couplings for each mobile robot, etc.);information on the farming operation schedules (for e.g. identifying where and when other vehicles may station or travel, etc.);crop rotation schedules (for e.g. identifying areas that need to be avoided when moving the mobile robots, etc.); etc.

The operational information in such a database may be gathered:manually (i.e. entered by a human operator); and/orautomatically extracted from online sources (weather services, etc.); and/orautomatically extracted from other databases of other similar systems for generating electrical energy; and/orobtained by measurements made by sensors of the mobile robots (for instance, one more mobile robots may be programmed to use onboard sensors to monitor each target area to collect relevant weather, ground surface and activity information, etc.), etc.

It is emphasized that the array controller may be external from the system for generating electrical energy. In that case, the system for generating electrical energy receives an array configuration from an external array controller. In other examples, the array controller may be internal to the system. In such a case, the array controller may be implemented in a device distinct from the mobile robots or, alternatively, may be implemented in a mobile robot, preferably in a collecting robot10.

Once the array configuration is determined, each mobile robot that will be used for forming the array at the target area may be informed of all or part of the array configuration. For instance, each mobile robot may receive information on its own target position and target orientation, and on the couplings that are to be established with its adjacent mobile robots. Other information may also be received such as the scheduled time interval(s) for generating electrical energy, a sequence of movement (if the mobile robots do not move simultaneously to the target area), etc.

During step S81, the uncoupled mobile robots are commanded to move from their respective current positions to their respective target positions and target orientations of the array configuration.

During step S82, the input ports11,21and output ports12of the mobile robots of the array are coupled according to the couplings defined in the array configuration.

During step S83, the array of coupled mobile robots generates electrical energy which is output at the output port12of the collecting robot10.

It is emphasized that the steps S80, S81, S82and S83of the method80for generating electrical energy are not necessarily executed one after the other, as may suggestFIG.9, and may for instance be executed in parallel.

For instance, it is possible to move first at least one mobile robot to the target area, for instance the collecting robot10(step S81for the collecting robot10). The collecting robot10may acquire data (e.g. images, etc.) that is used to determine the array configuration (step S80). Once the array configuration is determined, a first producing robot20may be moved to the target area (step S81for the first producing robot20) and coupled with the collecting robot10(step S82for the first producing robot20). Then a second producing robot20may be moved to the target area (step S81for the second producing robot20) and coupled (directly or indirectly) with the collecting robot10(step S82for the second producing robot20), etc., until all the producing robots20of the array have moved to the target area and coupled (directly or indirectly) with the collecting robot10. Also, the generation of electrical energy (step S83) may start as soon as the collecting robot has reached its target position or, alternatively, may start only once some or all mobile robots of the array are coupled.

As discussed above, the mobile robots of the array may also be used to accomplish other tasks, such as shadowing temporarily an area in the vicinity of the target area where the temporary PV installation is formed, in order to e.g. protect said area from the sun, from heavy rain, from hail, from snow, etc. This may for instance be accomplished by moving all of part of the mobile robots of the array above the area to be shaded. Hence:during a first time interval, at least, the mobile robots are coupled to form the array and to generate electrical energy; andduring a second time interval, at least: all or part of the mobile robots of the array are moved above the area to be shaded.

As discussed above, the shadowing may be accomplished while maintaining the mobile robots used coupled together or, alternately, the mobile robots used for shadowing may be uncoupled beforehand and the uncoupled mobile robots may be moved above the area to be shaded.

If the mobile robots remain coupled together, then the generation of electrical energy may continue while shadowing the area to be shaded. In that case, using an untethered collecting robot10makes it easier to move the array while simultaneously transferring in an efficient manner the generated electrical energy to an extraction point. Also, if the mobile robots remain coupled together for shadowing, then the coupled mobile robots may be moved by using all the displacement means14,24of the coupled mobile robots, or by using only some of the displacement means14,24of the coupled mobile robots (i.e. the displacement means14,24of some of the coupled mobile robots are not activated, e.g. to save electrical energy).

If the mobile robots are UAVs, then the mobile robots preferably fly over the area to be shaded.

If the mobile robots are UTVs, then each mobile robot used for shadowing is preferably configured such that there is room below its main body. For instance, the main body has a bottom face that is positioned (or that can be positioned if e.g. the main body is movable vertically) at a height with respect to the ground that is higher than or equal to 0.5 m, or preferably higher than or equal to 1 m.

As discussed above, the mobile robots may also be used for shadowing the target area where they are stationed for generating electrical energy. Preferably, the mobile robots are equipped with means for dynamically modifying the inclination of their PV surface, thereby dynamically adapting the shadow generation at the target area, while generating electrical energy.

It is emphasized that the present invention is not limited to the above exemplary embodiments. Variants of the above exemplary embodiments are also within the scope of the present invention.

For example, the invention has been described considering mainly an array comprising a single collecting robot10. However, it is also possible, in other examples, to form an array of coupled mobile robots comprising a plurality of producing robots20and two or more collecting robots10, for instance if two or more extraction points are required at the target area.

Also, it is possible to consider other environmental elements such as rain, hail, snow, etc. For example, inclination modifying means may be used to modify the inclinations of the PV surfaces of the mobile robots to provide a temporary protection against environmental hazards when the electrical energy stored by the mobile robots is sufficient for their own operations as well as for the delivery of electrical energy, etc.