BE1029275B1 - Mobile robot and method of moving a mobile robot - Google Patents

Abstract

The invention relates to a mobile robot (1) comprising a navigation system (4) and an electronic unit (2), the latter comprising a probe (3) for interacting with a wet portion of a geographical area (9) on which moves the robot (1). The electronic unit (2) is configured to generate a signal (5) from an interaction of the probe (3) with the wet portion, and to transmit the signal (5) to the navigation system (4). The navigation system 4 is itself configured to control the movement of the robot (1) according to this signal (5). The invention also relates to a method for moving such a mobile robot (1) on the basis of the signal (5) thus generated by the electronic unit (2).

Description

- 1 - Mobile robot and method of moving a mobile robot Technical field

The invention introduced in this document relates to a mobile robot, for example, a robotic mower, and a method of moving such a mobile robot. Prior art

To control the movement of a robotic mower in a geographical area, it is known to provide it with a navigation system. The mower then moves in a determined geographical area, taking into account instructions received by the navigation system and/or position data received by a receiver of a satellite positioning system. Generally, such a navigation system is satisfactory for controlling the movement of the mower, and this in complete safety. In particular, account can thus be taken of any permanent bodies of water (for example, a lake, a pond, etc.) known in the geographical area which are to be avoided by the mower.

[0003] However, all the bodies of water in the geographical area are not necessarily permanent and of constant dimensions over time. For example, puddles that appear following heavy rainfall, or simply because of permanent humidity at ground level in the geographical area, can constitute a body of water. Such "puddles" can also be more or less extensive depending on the situation. Considerable parts of the geographical area can also sometimes be flooded, especially in (sub-)tropical countries. These unexpected formations of puddles, or even floods, unfortunately tend to become more and more frequent in other regions of the world due to climate change.

[0004] It is of the utmost importance for the robotic mower to avoid moving through such puddles, in flooded portions of the geographical area, or in general, at the level of any expanse of water, permanent or not. Indeed, when the mower enters such an expanse

- 2- of water, its functioning and ability to move may be affected. The mower may be submerged and/or seriously damaged. Disclosure of Invention

[0005] An object of the present invention is to provide a mobile robot, for example a robotic mower, capable of detecting and/or avoiding bodies of water, in particular non-permanent bodies of water and/or of variable dimensions over time, such as puddles and flooded portions of a geographical area over which the mobile robot moves.

[0006] To this end, the invention proposes a mobile robot comprising: - a motor drive unit; - a navigation system coupled to the motor drive unit to control movement of the robot in a geographical area; and - an electronic unit: e comprising a probe able to interact (electrically) with a wet portion of the geographical area consisting of a body of water, e configured to generate (electronically) an (electrical) signal from an interaction (electric) of the probe with the wet portion, e coupled (electronically) to the navigation system to transmit the signal to it, the navigation system being capable of modifying the movement of the robot when the signal is transmitted to the navigation system by the electronic unit.

[0007] The robot according to the present invention makes it possible to detect and adapt its movement to the presence of a body of water in the geographical area in real time, in particular a body of permanent, non-permanent and/or varying in size over time. Indeed, the robot is advantageously provided with an electronic unit comprising a probe intended to detect such a body of water through its interaction with it. Such a typically electrical interaction allows the electronic unit to generate an electrical signal which can be transmitted and processed appropriately to the navigation system. The signal therefore includes in a certain way the information of the detection of the body of water by the

- 3- probe. When the navigation system receives this signal, it is finally able to take it into account in determining the movement of the robot. In particular, a modification and/or an adaptation of the movement of the robot when the signal is received by the navigation system preferably comprises avoiding the body of water.

[0008] In the invention, the coupling between the motor drive unit and the navigation system is preferably electrical and/or electronic and allows the navigation system to send instructions for moving the robot in the geographical area , these corresponding to the control of the movement of the robot determined by the navigation system.

[0009] Although the navigation system is capable of modifying the control it exercises over the movement of the robot when the signal is transmitted to it, it preferably only takes this signal into account in a normal operating mode of the robot. For example, this signal may have no effect when the robot is maneuvering, reversing, standing still, or moving towards a power supply station. Similarly, the electronics unit can also be configured so that the probe only actually interacts with the wet portion in such a normal operating mode of the robot. In the context of the invention, the probe is capable of interacting with the wet portion when the robot moves at the level of the wet portion, and the navigation system is also configured to receive the signal, preferably electronically, when it is transmitted to him.

[0010] In the context of this document, the term "robot" refers to any known robotic machine. It may for example be a robotic mower, a robotic vehicle, etc. According to a preferred embodiment of the invention, the mobile robot consists of a robotic mower. The mower is typically configured to mow at least a grassy portion of the geographic area.

[0011] In the context of this document, the term “geographical area” is used to designate an area of land over which the robot is able to move. Such an area preferably comprises a grassy portion (or surface) (or even patch of grass), in particular, when the robot consists of a robotic mower. Furthermore, the term "zone" used in this text does not

- 4 - should not be construed limitingly as referring to an area in one piece.

[0012] In the context of this document, the terms "based on", "depending on", or even "from", should not be interpreted restrictively as corresponding to the fact that only the elements cited after these terms are taken into account.

[0013] The use, in this document, of the verb “to understand”, of its variants, as well as its conjugations, cannot in any way exclude the presence of elements other than those mentioned. The use, in this document, of the indefinite article "UN", "une", or of the definite article "le", "la" or "1", to introduce an element does not exclude the presence of a plurality of these elements. The terms "first", "second", "third", etc. are, for their part, used within the framework of the document to differentiate elements at least formally, and this without implying any order between these elements.

According to a very preferred embodiment of the present invention, the probe comprises a pair of electrodes having a potential difference which are arranged to come into electrical contact when the robot moves at the level of the wet portion.

This embodiment of the probe is particularly advantageous. It is simple and efficient to implement because it simply requires the provision of two electrodes, for example segments of metal cables, having a potential difference. The potential difference can be obtained by connecting only one of the two electrodes to a power supply. Thus, the probe is simple and inexpensive. Its operation is based simply on the electrical conductivity of water. When the robot moves at the level of the wet portion, the probe is capable of interacting with it due to the fact that the water of the wet portion conducts the electric current from one electrode to the other, so as to form a closed electrical circuit between the electrodes within the electronic unit, which allows the generation of the signal. In particular, in this case, the electrical contact between the electrodes and the wet portion constitutes the aforesaid interaction between the probe and the wet portion.

- B.

Preferably, the pair of electrodes is at least partially formed of two metal cables extending at a distance from each other, and each of which comprises a lower extremal segment arranged to come into electrical contact with the wet portion . According to a particular embodiment, each metal cable is surrounded by an electrical insulator, for example made of PVC, except on its lower extremal segment to facilitate electrical contact with the wet portion. Each such cable can easily be obtained from a cable entirely covered with the insulation which it suffices to strip of insulation in its lower extremal segment. The latter is preferably 1 to 10 millimeters long, more preferably about 5 millimeters. The distance between the two cables, particularly at their lower extremal segments and in their immediate vicinity, is preferably at least five centimeters in order to prevent grass and/or mud from electrically connecting the two electrodes between them during operation of the mobile robot, and that a signal is then generated by the electronic unit without this being necessary. This distance is preferably about 10 centimeters. It preferably applies to the cable segments corresponding to the electrodes when the cables extend beyond them.

[0017]Each cable more preferably has a reserve segment capable of allowing the lower extremal segment to be replaced. This reserve segment corresponds in other words to the slack of each cable. This embodiment is very advantageous because it allows a very easy and cost-free replacement of a worn electrode, or more specifically in this case, of a lower extremal segment of worn cable. Such wear is liable to occur during use of the mobile robot given the position of the electrodes (and of the probe in general) in direct proximity to the ground of the geographical area so as to be able to interact with the wet portion. Indeed, at this position, the lower extremal segments are likely to undergo friction and/or shock during possible contact with the ground (for example, with higher grassy portions and/or unevenness), and therefore to s wear faster than the rest of the cables. In which case, to replace a lower extremal segment of a cable,

- 6 - it is very advantageously sufficient to cut it from the cable and to pull on the cable in order to exploit the reserve segment to constitute a new lower extremal segment. When the metal cables are surrounded by an electrical insulator, it is also sufficient to strip the insulation from the new lower extremal segment thus obtained. It is thus possible to maintain and repair a worn electrode (or more precisely in the present case, a worn lower extremal segment) at no cost, quickly. The reserve segment is preferably 1 to 10 centimeters long, more preferably it is about 5 centimeters long, both to have enough slack in the cable to carry out this operation, while avoiding that the cables are not too long to the point of being cumbersome and of difficult positioning to control due to the curvature of the cables at the level of the reserve segments.

Preferably, each cable is made at least partially (and preferably totally) of stainless steel. Stainless steel makes it possible both to avoid oxidation of the cable and to limit its wear, in particular at the level of its lower extremal segment. Each cable is preferably of a tubular shape with a cross-sectional diameter of less than 5 millimeters. Preferably, the section diameter of the cable is less than 3 millimeters, more preferably around 2 millimeters. The cable is preferably surrounded by a layer of an electrical insulator with an average thickness of one millimeter or less, preferably about 1 millimeter. The wire rope with this layer thus preferably has a tubular shape with an overall cross-sectional diameter of 6 millimeters or less, and preferably about 3 millimeters. The cable is thus generally particularly flexible and resistant, and therefore perfectly suitable for forming an electrode arranged in direct proximity to the ground of the geographical area during operation of the mobile robot so as to be able to come into electrical contact with the wet portion. In particular, the probe as a whole is thus more robust to possible shocks and friction that it could undergo at ground level during the operation of the mobile robot.

According to a preferred embodiment of the invention, the robot comprises a front end and a rear end, the front end being arranged to

-7- preceding the rear end in a (main) direction of movement, along a direction of movement of the robot, the probe of the electronic unit being arranged at the level of the front end of the robot.

[0020] By “direction of movement”, it is preferably to mean the tangent (therefore a straight line) to the global trajectory of the robot at each point of the latter. Hence, a "direction of movement" along the direction of movement corresponds to an orientation along this direction, in other words, which makes it possible to distinguish a forward or reverse movement of the mobile robot along its overall trajectory, as known to a person skilled in the art. At each point of this global trajectory, the direction and the direction of displacement therefore define a vector as represented in FIGS. 3 and 5 introduced below. The main direction of movement corresponds to the forward motion of the mobile robot, that is to say its usual and majority direction of movement. Placing the probe at the front end of the robot is advantageous for detecting bodies of water in the sense described in paragraph [0007] because the probe then precedes, in the main direction of movement of the mobile robot, the main of the mobile robot, so that a body of water is detected before the mobile robot enters it. This allows the electronic unit to generate the associated signal and transmit this signal to the navigation system so that the latter can quickly modify the movement of the mobile robot if necessary, and before it is completely in the body of water. By an arrangement of the probe "at the level of the front end of the robot", it is not necessarily meant that the probe is arranged to precede the front end of the robot in the (main) direction of movement thereof, but rather that the probe is located in a direct vicinity of the front end, along the direction of movement, as illustrated in Figures 2, 3 and 5 introduced below.

According to a preferred embodiment of the invention, the robot is provided with a deflector and the probe is mechanically coupled, preferably fixed, to the deflector. The deflector can take the form of a simple plate for example. According to the above embodiment, the deflector is then preferably arranged at the level of the front end of the robot. In this case it has a

- 8- front face oriented mainly towards the front end of the robot and a rear face oriented mainly towards the rear end of the robot. The probe is then more precisely arranged on the rear face of the deflector. Advantageously, the deflector plays a protective role for the probe, in particular with respect to hitches, shocks and/or friction that the probe could undergo given its position in direct proximity to the ground of the geographical area.

[0022] = Beyond this protective role, the deflector also makes it possible to limit the interactions and/or contacts of the probe with the grass of the geographical area in the embodiments for which the probe does not extend beyond the lower deflector (i.e., when the probe is no closer to the ground than the deflector itself). Indeed, in some cases, the probe can interact with wet grass in the geographical area, so that the signal is thus generated by the electronic unit without this being an objective pursued (for example, when only the detection of wet portions corresponding to bodies of water is desired). This is the case, for example, of the embodiments of the probe described in paragraphs [0014] to [0018] given that wet grass is conductive. Thus, by placing the probe at the rear of the deflector according to the (main) direction of movement of the mobile robot, the latter is not only at least partially protected from the damage it could suffer, but also from false detections. wet portions are thus avoided.

[0023] According to one embodiment of the invention, the robot comprises wheels mechanically coupled to the motor drive unit to support and/or steer the robot in the geographical area, the wheels comprising at least one driving wheel. The probe is then preferably aligned with the drive wheel along a direction of movement of the robot. In this way, given the position of the probe at the front end of the mobile robot, the probe can detect the wet portion before the drive wheel enters it and therefore prevent this wheel from being submerged and/or bogged down in the wet portion, which could have negative consequences on the operation of the mobile robot and its ability to move. This particular positioning of the probe is therefore particularly judicious.

- 9-

[0024] Preferably, the probe overhangs a wheel support plane with a height of between 5 and 15 millimeters, preferably between 7 and 11 millimeters, more preferably approximately 8, 9 or 10 millimeters. wheels” corresponds to a plane supporting the wheels in an equivalent manner, preferably a horizontal plane (corresponding to a portion of flat ground in the geographical area). In other words, this height corresponds to the distance between the probe and (the ground of) the geographical area when operating the mobile robot on essentially flat ground. This height is chosen to be large enough to avoid interaction of the probe with a thin layer of water likely to appear during heavy rains over portions of the geographical area, and therefore ultimately to avoid detection of such a layer. of water when it is not wanted. However, the height is also chosen to be small enough to detect shallow bodies of water in the geographical area.

The previous embodiment is however limited when it comes to detecting and / or avoiding a wet portion of the geographical area (for example, a body of water) of small size present at the foot of an upward or downward slope laterally to the mobile robot, because in this case, the possible placement of the probe at the front end of the robot at said height of the wheel support plane, does not allow appropriate interaction with the wet portion, so the wet portion is not always detected. Therefore, in general, according to any other embodiment of the invention proposing a probe provided with a pair of electrodes formed of two metal cables having a potential difference, for example as described in paragraph [ 0016], each electrode is preferably provided with a ballast through which one of the cables passes and from which the lower extremal segment of the cable protrudes, so that the latter overhangs a lower part of the ballast.

This embodiment is particularly advantageous when it is desired to detect all bodies of water (including a small puddle of water). Indeed, as the cable and its lower extremal segment overhangs the lower part of the ballast, it is understood that the cable then extends below the

- 10 - ground level of the geographical area, so that the ballast drags on the ground while allowing the cable to be maintained at ground level, without it touching the ground, at a height which can be chosen by the arrangement of the lower extremal segment with regard to the ballast as described in paragraph [0027]. In particular, the ballast plays an important role in this embodiment not only to maintain the cable at ground level and to guide it by inertia, but also to avoid unwanted electrical interactions of the electrodes with a portion of wet grass of the geographical area (as described in paragraph [0022]). Preferably, the ballast is made of an electrically non-conductive material. Optionally, it can be conductive when the entire crossing part of the cable is covered with a layer of electrical insulation (as described in paragraphs [0016] and [0017]), or in other words, when the cable is insulated electrically from ballast. Thus, even when water from a body of water does not submerge any part of the robot (for example, the front end, or a deflector when the robot includes one) to a height of at least 5 millimeters, it It is possible to detect the body of water because the lower extremal segments of the cables and the ballast dragging on the ground will penetrate into the body of water.

[0027] The ballast is preferably of essentially ellipsoidal shape, each half-axis of which is at least 5 millimeters. The ballast is more preferably of spherical shape (all the semi-axes then being equal and corresponding to the sole radius of the sphere). These shapes advantageously easily allow the weights to slide on the ground of the geographical area regardless of its relief, by maintaining the lower extremal segment at a height of a few millimeters from the ground, this height being chosen for the same reasons as those set out in paragraph [0024]. Preferably, the smallest semi-axis (or the radius in the case of a spherical shape) on which this height depends is between 5 and 15 millimeters, more preferably between 7 and 11 millimeters, and it is, more preferred, about 8, 9 or 10 millimeters.

[0028] According to any embodiment of the invention as described in paragraph [0023], the wheels of the mobile robot comprise:

- 11 - e two driving rear wheels (being closer to the rear end than the front end of the robot), and e a front wheel (being closer to the front end than the rear end of the robot) , the robot comprising two such similar probes, each being aligned with one of the rear wheels along the direction of movement of the robot, each being able to interact with the wet portion, the electronic unit being configured to generate the signal from an interaction of at least one of the probes with the wet portion. The advantages of this embodiment include those mentioned in paragraph [0023] for each drive wheel, but also the fact that the detection of the wet portion by the electronic unit is possible both on the left side and on the right side of the robot . In this respect, the signal generated by the electronic unit from an interaction of one of the probes with the wet portion is preferentially distinguishable by the navigation system from the signal generated by the electronic unit from an interaction of the other probes with the wet portion, so that the navigation system not only receives information on detecting the wet portion, but also information on the position of the latter relative to the mobile robot (to the left and/or or right), so that he can take this into account in his control of the robot's movement. The mobile robot is therefore all the more effective in detecting and/or avoiding such wet portions.

[0029] The considerations of paragraph [0028] can of course be generalized to any number of probes positioned appropriately. For example, probes may be provided on the left, right, and/or middle of the front end of the mobile robot, and/or similarly at the rear end of the mobile robot, possibly with some probes in a alignment of the drive wheels along the direction of movement of the mobile robot.

[0030] The invention as it is exposed in general in paragraphs [0006] and [0007] clarifies the ability of the probe to interact with a "wet portion" consisting of a body of water and that of the unit electronics to generate a signal from this interaction. In this presentation, the wet portion corresponds

- 12 - to a body of water. However, the operation of the electronic unit which is thus exposed is not specifically limited to this type of wet portion. It can in particular apply to other more broadly defined wet portions, so that all of the preceding description of the invention can apply for such a “wet portion” (hence the use of this generic term above).

[0031] More specifically, and preferably: - the probe is (also) capable of interacting with the wet portion when the latter consists (more generally) of a portion of the geographical area having a humidity rate of at least a first humidity threshold, so that the electronic unit generates the signal from an interaction of the probe with the wet portion; - the electronic unit is (also) configured to transmit the signal to the navigation system if the humidity level of the wet portion is at least a second humidity threshold.

[0032] In this case, and in a manner compatible with the previous embodiments, the term "wet portion" is therefore interpreted more broadly as a portion of the geographical area having a humidity level of at least the first threshold humidity. In this context, any “moisture content” can be used, in particular and preferably, a mass or volume content. The first and second humidity thresholds are humidity levels. All the thresholds and humidity levels considered are preferably of the same nature, for example, by volume. Although first and second humidity thresholds are mentioned above, there is not necessarily an explicit measurement of the humidity level within the electronic unit. The first humidity threshold simply corresponds preferably to a threshold above which the probe is able to interact. This is easily understood, for example, in the case of a probe comprising two electrodes subjected to a potential difference. In this case, the passage of a minimum electric current between the two electrodes will require a certain humidity level which may, for example, depend on the distance between the electrodes.

Thus, there is not necessarily a humidity level measurement in order to activate the probe. Preferably, its configuration makes it suitable for

- 13 - interact with the wet portion if its humidity level is high enough. This makes it possible to solicit the probe only for sufficiently high levels of humidity, and therefore the wet portion is likely to represent a sufficient danger for the integrity of the mobile robot.

[0033] In the same way, the general signal by the electronic unit may not be transmitted to the navigation system if it turns out, after generation of the signal by the electronic unit, that the humidity level does not was not above the second humidity threshold. Thus, only detections of wet portions of sufficiently high humidity levels will be signaled to the navigation system via the signal. The use of two thresholds makes it possible to limit errors due to non-interaction of the probe with the wet portion. Thus, the second threshold is preferably higher than the first threshold, so as to guarantee more basic interactions of the probe with the wet portions of the geographical area, even if it means not necessarily transmitting all the signals generated by electronic unit to the system. of navigation if the wet portions detected do not represent a significant danger for the integrity of the mobile robot.

[0034] For example, the first humidity level can be around 10, 20, 30, 40 or 50% by volume of water, and the second humidity level can be around 50, 60, 70 , 80 or 90% by volume of water. In all cases, a body of water is considered to have a humidity level of 100% or close to 100%, so that a body of water always constitutes a wet portion with a humidity level higher than the first and second humidity threshold, and is therefore necessarily provided to be detected by the electronic unit.

[0035] Indirectly, this embodiment also allows identification of a humidity level of a wet portion greater than the first and second humidity thresholds by the electronic unit, so that this information can also be used. For example, it can be transmitted to a user or to a remote electronic device by a (wireless) transmitter of the mobile robot, it can alternatively or in combination be stored on a data carrier of the electronic unit, and/or also transmitted to a logical unit of the system of

- 14 - navigation to determine paths of movement of the robot in the geographical area.

According to a preferred embodiment, the electronic unit comprises: - a source of electrical energy for the probe having an input voltage; - An electronic circuit for electronically generating the signal so that the latter has an output voltage below a maximum voltage threshold.

The interaction of the probe with the wet portion is thus electrical and generated from the energy supplied by the energy source. In the case of a probe comprising two electrodes, it is preferably the energy source which makes it possible to obtain a potential difference between the two electrodes, one of these electrodes being connected to the energy source, the other no. Preferably, the input voltage is between 5 and 20V, more preferably it is around 12V.

The electrical interaction between the probe and the wet portion is captured in the electronic circuit and electronically transformed into an electrical signal having an output voltage suitable both for its transmission and its processing by the navigation system. The electronic circuit preferably comprises one or more of: a first (resistive) voltage divider, a Zener diode, an operational amplifier, and/or a second (resistive) voltage divider, more preferably, successively along the electronic circuit. Such an electronic circuit is illustrated in FIG. 7 introduced below. It advantageously allows great sensitivity to the detection of any type of wet portion. It thus becomes possible to differentiate between different humidity levels, in particular, to differentiate between a portion comprising wet grass and a real expanse of water. The electrical signal thus generated preferably has an output voltage comprised in an interval of predetermined values suitable for the electronic transmission of the signal to the navigation system. Preferably the output voltage is less than 5V, more preferably it is equal to or less than 3.3V.

[0039] When this embodiment is considered for a wet portion consisting of a portion of the geographical area having a humidity rate of at

- 15 - the lower the first humidity threshold, the higher the humidity level of the wet portion, the more electric current will be able to flow from the probe, so that an output voltage of the signal will be higher. The second humidity threshold is thus preferably implemented as a minimum output voltage necessary for the electrical signal to be transferred to the navigation system. In the case of the aforementioned electronic circuit, for an output voltage of less than 3.3V, an output voltage of 1.5V or less corresponds to a wet portion consisting of simply wet grass (for example, by rain ), and an output voltage of 2.2V or more corresponds to a body of water, for example, a puddle. Thus, in this case the minimum output voltage can be between 1.5 and 2.2V, for example, approximately 2V, so as to detect puddles with sufficient certainty, while ignoring a portion of grass. just damp.

[0040] According to a preferred embodiment of the invention compatible with the previous embodiments, the navigation system comprises: - A receiver for receiving position data from the robot, the control of the movement of the robot being done on the basis of the position data; and - a transmitter configured to transmit the position data of the robot to a remote electronic device when the signal is transmitted to the navigation system by the electronic unit, and/or a data medium on which the navigation system is able to record the position data of the robot when the signal is transmitted to the navigation system by electronic unit.

[0041] This embodiment advantageously makes it possible to transmit and/or record corresponding position data when the signal is transmitted to the navigation system, so that the positioning of an edge of a wet portion in the geographical area can thus be transmitted and/or recorded. The transmission by the transmitter is preferably done wirelessly. The electronic device can be a computer or a smartphone of a user so that he can be notified in real time of the presence (and more particularly, for example, of an unforeseen formation) of a wet portion (for example , a

- 16 - temporary puddle) in the geographical area. The data recorded on the data medium is preferably accessible remotely by wireless network and/or by contact (for example, by connection to a computer so as to retrieve the data). It is thus possible to collect the recorded position data and to analyze them a posteriori to optimize the movement of the robot in the geographical area according to the topological specificity of sub-areas of the geographical area and/or other parameters such as the weather, seasons, etc. In particular, when the signal contains information other than a simple "on/off" detection (for example, a variable output voltage as described in paragraph [0039], and/or a positioning of the probe having interacted with the wet portion as described in paragraphs [0028] and [0029], and/or a time datum, and/or any other information described in this document or derivable by a person skilled in the art), the transmission and/or the recording of position data can also be accompanied by the transmission and/or recording of all or part of this information.

[0042] These embodiments of the invention can also be used for the purposes of mapping the wet portions of the geographical area thanks to the position data progressively transmitted and/or recorded. Likewise, according to said available information, their evolution as a function of time, and/or their dependence on the weather (in particular precipitation), the seasons or any other relevant parameter can also be identified. In particular, and generally, the present invention also and advantageously proposes the use of the robot according to the invention to detect and/or map bodies of water in a geographical area.

[0043] Furthermore, the receiver can allow automatic control of the movement of the robot in the geographical area, depending on the real-time position of the robot. Generally, the mobile robot according to the invention is preferably autonomous or semi-autonomous. In particular, in this case, the control of the movement of the robot is preferably carried out autonomously or semi-autonomously according to the position data received. Further, the term "position data" should not be construed limitingly to refer to

- 17 - strict spatial coordinates, but extends to any data relating to the position of the robot. In particular, the receiver can be an integral part of a positioning system which would be, for example, by camera, by lidar, by radar, by sonar, by detection of the magnetic fields generated by an electric wire limiting the geographical area, and/ or by satellite, these examples not being limiting.

The receiver is preferably a GNSS receiver, that is to say a receiver of signals from a satellite positioning system (for example, GPS, GLONASS, Beidou, Galileo, etc.). The position data received by these receivers are then GNSS coordinates. The receiver is preferably a GNSS RTK receiver, that is to say, a GNSS receiver by real-time kinematics. A GNSS RTK system is known to a person skilled in the art and comprises, in addition to the conventional GNSS system, a fixed receiver whose position is precisely known making it possible to compare the position data received from the GNSS system with this known position, so as to deduce real-time corrections (known as RTK) from the position data and thus increase their accuracy. This fixed receiver also allows these RTK corrections to be sent to the mobile GNSS receiver of the robot's navigation system, so that the latter takes them into account. This sending can be carried out by a wireless communication network. The mobile GNSS receiver is then able to receive the RTK corrections, and programmed to determine corrected position data from these corrections and the position data. The navigation system is then programmed to control the movement of the robot on the basis of the corrected position data. It is preferably this corrected data which is then transmitted by the transmitter and/or recorded on the data medium. In addition, the use of a GNSS RTK receiver makes it possible to achieve position data accuracies of the order of a few centimeters (at worst 10 centimeters, and under ideal conditions of the order of 1 to 2 centimeters), and therefore both to fully meet the need to precisely control the movement of the robot in the geographical area, and to transmit and/or record precisely the positions at which a wet portion is detected as described above.

- 18 -

According to another advantageous embodiment of the mobile robot, the electronic unit comprises a test unit comprising: - a measurement module similar to the probe, arranged similarly to the probe, in a (direct) vicinity of the probe , so that it is able to interact similarly to the probe with the wet portion; - A comparison module electronically coupled to the probe and to the measurement module configured to carry out a comparison between the interactions of the probe with the wet portion and the interactions of the measurement module with the wet portion; - an alert module electronically coupled to the comparison module and configured to emit an alert signal based on a number of consecutive interaction differences in the comparison.

This embodiment applies in combination with the previous embodiments, regardless of the shape of the probe. The test unit is used to check that the probe is working properly and to emit an alert signal in the event of a malfunction. In particular, when the measurement module interacts several times consecutively with a wet portion without this being the case with the probe, it can be considered that there is a sufficiently high probability that the probe is defective and that it must be verified (for example, by commanding the robot to return to a base station). As explained in paragraphs [0018] and [0019] for example, given the position close to the ground of the geographical area (or even in contact with it) is more likely to suffer damage due to friction and/or shocks. The test unit advantageously makes it possible to protect the robot against prolonged malfunction of the probe following such damage. It is preferably used a number of consecutive interaction differences greater than 1, preferably 3, 4 or 5, because, despite the measurement module being arranged in the direct vicinity of the probe, it is still possible occasionally that only the measurement module interacts with a wet portion only taking into account the relative position of the probe and the test module with the wet portion. The alert signal emitted may be any

- 19 - signal known to a person skilled in the art, such as a sound or light signal at the level of the robot, and/or the wireless transmission of an alert message on a remote electronic device of a user, for example a computer or a smartphone.

Another object of the present invention is to provide a method of moving a mobile robot making it possible to detect and/or avoid bodies of water, in particular bodies of water that are not permanent and/or of dimensions variable over time.

To this end, the invention proposes such a method for moving a mobile robot comprising: - a motor drive unit; - a navigation system coupled to the motor drive unit to control movement of the robot in a geographical area; the method comprising the following steps: (1) providing the robot with an electronic unit: e comprising a probe capable of interacting with a wet portion of the geographical area consisting of a body of water, e configured to generate a signal from an interaction of the probe with the wet portion, e coupled to the navigation system to transmit the signal to it; (ii) controlling the movement of the robot in the geographical area by means of the navigation system, so as to move the robot at the level of the wet portion and to create an interaction between the wet portion and the probe; (ii) generating the signal from the interaction of step (ii) using the electronic unit; (iv) modify the movement of the robot in the geographical area by means of the navigation system based on the signal generated in step (iii) when it is transmitted to the navigation system by the electronic unit.

All the advantages of the mobile robot according to the present invention transpose mutatis mutandis to the present method. This method therefore makes it possible to detect and adapt the movement of the robot to the presence of an expanse.

- 20 - geographic area in real time. Similarly and preferably, the mobile robot obtained after step (i) is according to the invention and the method can be considered as a method for moving this mobile robot.

In general, all the embodiments of the mobile robot according to the invention and their advantages transpose mutatis mutandis to this method according to the invention. In particular, each of these embodiments of the robot, by virtue of the configuration and the functional capacities of the components of the robot which have been exposed in the preceding paragraphs, extends and translates as steps or sub-steps of the method according to the invention directly for a person skilled in the art.

[0051] For example, when the electronic unit supplied to the robot in step (i) is as described in paragraphs [0031] and [0036], the signal generated in step (iii) V is preferably electronically, by means of the electronic circuit so that the output voltage of the signal is lower than the maximum voltage threshold and proportional to the moisture content of the wet portion. In this case, the second humidity threshold preferably corresponds to a minimum voltage threshold of the signal, and step (iii) preferably comprises the sub-step: (ii) transmitting the signal generated in step (iii ) to the navigation system by means of the electronic unit when the signal output voltage is higher than the minimum voltage threshold. The advantages and the whole of the presentation of paragraphs [0031] to [0039] for the robot obtained by this particular step (i) naturally extend mutatis mutandis to this particular embodiment of the method according to the invention. . In particular, in the context of paragraph [0039], the minimum voltage threshold is preferably between 1.5 and 2.2V, preferably around 2 or 2.1V. In this specific case, the signal output voltage would therefore be between 2 and 3.3V. Brief description of figures

Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended figures, among which:

- 21 - - Figure 1 shows a schematic three-dimensional view of a mobile robot according to a first preferred embodiment of the invention; - Figure 2 illustrates a schematic top view of the robot illustrated in Figure 1; - Figure 3 illustrates a schematic side view of the robot illustrated in Figure 1; - Figure 4 illustrates a schematic view of a deflector and part of an electronic unit of the robot illustrated in Figure 1; - Figure 5 illustrates a schematic view of a mobile robot according to a second preferred embodiment of the invention; - Figure 6 illustrates a schematic view of a deflector and part of an electronic unit of the robot shown in Figure 5; - figure 7 represents an electronic diagram of an electronic circuit of an electronic unit suitable for the robots illustrated in figures 1 and 5.

The drawings of the aforementioned figures are not to scale. Like elements are generally denoted by like references in the figures. In the context of this document, identical or similar elements may bear the same references. This is, for example, the case for probes. Furthermore, the presence of reference numbers or letters in the drawings cannot be considered as limiting, including when these numbers or letters are indicated in the claims. Detailed description of embodiments of the invention

This part of the text introduces a detailed description of preferred embodiments of the present invention. This description refers to figures but the invention is in no way limited by them. The figures described below are only schematic. Furthermore, this description presents, without any loss of generality, two preferred embodiments of the invention where the mobile robot consists of an autonomous robotic mower having a large number of claimed characteristics, without the present invention being limited thereto. to all these characteristics. By abuse of notation, this mower will also be designated by reference 1.

- 22 -

The first embodiment is shown in Figures 1 to 4, of which Figures 1 to 3 illustrate different views of such a mower 1. It will be understood by a person skilled in the art that the mower 1 can and does understand Moreover, preferably the functionalities of a usual autonomous robotic mower, as well as a relatively standard exterior overall structure. For example, it will not surprise those skilled in the art that mower 1 includes cutting blades for cutting grass without this element being specifically described and/or illustrated.

The mower 1 is provided with a motor drive unit (which is not specifically illustrated) and wheels 71, 72 visible in Figure 3 and mechanically coupled with the motor drive unit to support and / or direct the mower 1 in a geographical area 9. The wheels 71, 72 comprise two front wheels 71 for support and steering closer to a front end 11 than to a rear end 12 of the mower 1, and two wheels rear 72 driven closer to the rear end 12 than the front end 11. The invention is obviously not limited to this arrangement or to this number of wheels 71, 72 as is known to a man of the trade. At each point of a given trajectory of the mower 1, a direction of movement D can be defined, illustrated in FIG. 3. The main direction of movement S of the mower 1 along this direction corresponds to the common sense of the term at the forward, and is such that the front end 11 precedes the rear end 12 along the aforesaid path.

The mower 1 further comprises a navigation system 4 coupled to the motor drive unit in order to control the movement of the mower 1 in the geographical area 9. In particular, the geographical area 9 typically comprises grassy portions 91 to mow. The mower 1 also advantageously comprises an electronic unit 2 comprising: - two probes 3 arranged at the level of the front end 11 (left and right) of the mower 1 to interact electrically with a wet portion of the geographical zone 9 (at the less) consisting of a body of water (temporary or permanent);

- 23 - - a source of electrical energy 22 (visible in Figure 7 below introduced) probes 3 having a preferred input voltage of approximately 12V; - an electronic circuit 21 (visible schematically in Figures 1, 2, 3 and 5, and in detail for one of the probes 3 in Figure 7 introduced below) configured to electronically generate an electrical signal 5 of a voltage of preferred output of less than 3.3V from interaction of at least one of the 3 probes with the wet portion. The electronic unit 2 (and more precisely the electronic circuit 21) is also coupled to the navigation system 4 so as to be able to transmit each signal 5 to it. The navigation system 4 is configured to receive this signal 5 thus transmitted, for example , preferably, taking into account a choice of maximum output voltage threshold adapted to a processor of the navigation system 4, and to modify the movement of the mower 1 if necessary (for example, under the conditions set out in paragraph [0009], for example). In these respects, the signal 5 originating from an interaction of the probe 3 placed at the level of the left front end 11 with the wet portion is preferably distinct and/or distinguishable by the electronic unit 2 and/or the system of navigation 4 of the signal 5 coming from an interaction of the probe 3 placed at the level of the right front end 11 with the wet portion.

As illustrated in Figures 1 and 2, the two probes 3 are aligned with the two rear wheels 72 along the direction of movement D. They are also arranged, preferably, along the direction of movement D at the same level as collision sensors 13 of mower 1, these being for example ultrasonic transmitters and/or receivers. Each probe 3 is preferably surmounted (above) by such a collision sensor 13 at the level of the front end 11 of the mower 1.

The probes 3 are similar. Such a probe 3 is illustrated in FIG.

4. It comprises electrodes 31, 32 having a potential difference which are arranged to come into electrical contact when the mower 1 moves at the level of the wet portion. Each electrode is essentially formed by a flexible metallic (e.g., stainless steel) cable surrounded by a

- 24 - sheath of an insulating material (for example, PVC), and stripped of this sheath over a short lower extremal segment 36 of 1 to 10 millimeters in length, for example 5 millimeters in length. It is more precisely this lower extremal segment 36 which is arranged to come into electrical contact with the wet portion so as to constitute the aforesaid interaction. To do this, this lower extremal segment 36 is maintained above the ground of the geographical area 9 so as to overhang the support plane P of the wheels 71, 72 of the mower 1 at a height h of between 7 and 11 millimeters, for example, 10 millimeters, as shown in Figures 3 and 4. Each cable 35 is provided with slack which corresponds to a reserve segment 37, so that in the event of wear of the extremal segment 36, it suffices to cut and remove the latter from the cable 35, to stretch the reserve segment 37 a little by pulling on the cable 35 so as to constitute a new lower extremal segment and finally to strip the latter of its protective sheath. insulating material, to replace the lower extremal segment 36 quickly and free of charge.

[0060] | In order to at least partially protect the cables 35 against damage and wear, to keep them in position, and to limit unwanted electrical contacts of the probe 3 (for example, with a wet grassy portion 91 if it is not desired to detect such a grassy portion), the probe 3 is provided with a deflector 6 in the form of a plate having a shape faithfully represented in FIG. 4. The deflector 6 comprises a front face 61 oriented mainly towards the front end 11 of the mower 1 as well as a rear face 62 oriented mainly towards the rear end 12 of the mower

1. These faces 61, 62 are particularly visible in Figure 2. The cables 35 are held in a stable position on the rear face 62 of the deflector, by attachment means 63, for example, as shown in Figure 4, plates for compression of the cables 35 and the fixing bolts of these plates on the rear face 62 on the deflector 6. The cables 35 are arranged on the rear face 62 of the deflector 6 at a preferred distance d of approximately 10 centimeters from one of the 'other.

[0061] Although the embodiment shown includes a deflector 6 as described, it will be understood by those skilled in the art that this is optional and

- 25 - that the cables 35 can simply be integrated under a casing of the mower 1, so that the end sections 36 are suspended at a height h under the front end 11 of the mower 1. Similarly, the deflector 6 is optional for the second embodiment introduced below.

The second embodiment is shown in Figures 5 and 6, the views of Figures 1 and 2 adapting quite similarly. All the structural elements of the first embodiment remain unchanged with the sole exception of a lower part of the electrodes 31, 32. Indeed, in this second embodiment, the cables 35 of the electrodes 31, 32 extend below the height h mentioned above for the first embodiment, so that a lower part of each electrode 31, 32 trails on the ground of the geographical area 9. This advantageously makes it possible to detect very small bodies of water 92 presenting for example laterally below mower 1 as illustrated in FIG. 5 and which would not be detected with a mower 1 of the first embodiment. Indeed, the front end 11 of the mower 1 could not lean towards the expanse of water 92 when moving the mower 1 in its vicinity given the small size of the hollow in the ground in which formed this body of water 92.

However, to obtain that a lower part of each electrode 31, 32 hangs on the ground of the geographical zone 9, a simple extension of the cable 35 in length is not recommended because this one, or at least its lower extremal segment 36, would then undergo significant friction and/or damage so that it would deteriorate more quickly. Furthermore, this lower extremal segment 36 would quickly come into electrical contact on a grassy portion 91, even moderately wet, so that the electronic unit 2 would thus generate a large number of potentially unwanted signals. To solve these problems, provision is made to provide each lower part of the electrode with a spherical ballast 38 of radius R as shown in FIGS. 5 and 6. In particular, FIG. 6 shows such a lower part of any electrodes 31, 32. The ballast 38 is crossed by the cable 35, the main part of the cable 35 emerging from one side of the ballast 38 and the lower extremal segment 36 of the cable 35 emerging from the other side of the ballast 38,

- 26 - for example, at antipodal points, chosen so that the lower extremal segment 36 (and/or the whole of the cable 35) always overhangs a lower part of the ballast 38. The radius R is preferably d about 10 millimeters. It is chosen in such a way that the lower extremal segment 36 is sufficiently high relative to the ground of the geographical area 9 (and therefore to the support plane P) in all circumstances. This makes it possible to limit the damage that this lower extremal segment 36 could suffer, as well as the number of electrical contacts of the electrode 31, 32 with the geographical zone 9 with more or less wet grassy portions 91 whose detection would not be not desired. Finally, as its name indicates, the ballast 38 also makes it possible, by its weight, to systematically maintain the lower extremal segment 36 at a height from the ground of the geographical zone 9. It should be noted that this height may occasionally be higher smaller than R depending on the orientation of the cable 35, the topography of the geographical area 9 and/or a particular positioning of the mower 1 at a given instant, but that it is always large enough so that at least the lower part of the ballast 38 is overhung by the lower extremal segment 36, and directly in contact with the ground of the geographical zone 9.

Finally, FIG. 7 illustrates an electronic diagram of the electronic circuit 21 according to a preferred embodiment. The electronic circuit 21 is represented with regard to one of the probes 3 introduced above, but a person skilled in the art will understand that two such electronic circuits 21 can be provided for the two probes 3, either independently (each being coupled to the system navigation system 4 to transmit their signals 5 generated respectively), or in a combined manner so as to ultimately constitute a single electronic circuit 21 coupled to the navigation system 4 and to which the probes 3 are connected.

The electrodes 31, 32 of a probe 3 are electrically connected to the electronic circuit 21 at points 31' and 32'. The aforesaid potential difference is more particularly given by the sole energization of one of the cables 35 corresponding to one of the electrodes 31 by means of the energy source 22. The choice of an input voltage of 12V associated with this makes it possible to reduce the electromagnetic disturbances linked to the external environment and/or to various

- 27 - electronic components of the mower. The geographical zone 9, in particular the wet portion, constitutes a variable resistor between the points 31' and 32' as shown in the diagram of FIG. 7, capable of allowing electrical contact between them. In which case, the primary electrical signal thus generated is electronically transformed by other components of the electronic circuit 21 into a signal 5 with a controlled output voltage, and preferably less than 3.3V (this value being indicative) in such a way that it can be transmitted to the navigation system 4, for example, via a microcontroller which analyzes the signal 5.

These other components are, for example, as shown in Figure 7, successively, a first resistive voltage divider 23, a Zener diode 24, an operational amplifier 25, and a second resistive voltage divider 26. These components are known to a person skilled in the electronics art. The first resistive voltage divider 23 and the Zener diode 24 make it possible to limit the voltage at the level of the operational amplifier 25 to 12V, the latter acting as a buffer to create galvanic isolation between the energy source 22 and the output of the electric circuit. The second resistive voltage divider 26 makes it possible, for its part, to limit the output voltage of signal 5 to 3.3V as mentioned above. The overall resistance of the electronic circuit 21 is chosen to obtain a high sensitivity of the signal 5, so that it is possible (if this is the objective pursued) to differentiate between a body of water and another wet portion. of the geographical area 9 having a certain humidity level as detailed in paragraphs [0031] to [0039] of the description of the invention. The electronic circuit 21 preferably does not use any capacitance or inductance to avoid a delay in detecting a wet portion via the generation of the signal 5.

The electronic circuit 21 is described as that of the electronic unit 2 of the mower 1. However, a person skilled in the art will understand that such an electronic circuit 21 is in no way limited to all the characteristics which have been explained above, from the moment when the electrodes 31 and 32 having a potential difference are connected to the electronic circuit 21. Similarly, the

- 28 - electronic circuit 21 is not limited to the presence of each of the electronic components represented, nor to their arrangement.

In summary, the invention relates to a mobile robot 1 provided with a navigation system 4 and an electronic unit 2, the latter comprising a probe 3 for interacting with a wet portion of a geographical area 9 over which the robot 1. The electronic unit 2 is configured to generate a signal 5 from an interaction of the probe 3 with the wet portion, and to transmit the signal 5 to the navigation system 4. The navigation system 4 is itself even configured to control the movement of the robot 1 as a function of this signal 5. The invention also relates to a method of moving such a mobile robot 1 on the basis of the signal 5 thus generated by the electronic unit 2.

The present invention has been described above in connection with preferred and/or specific embodiments, which are purely illustrative and should not be construed as limiting. In general, it will appear obvious to a person skilled in the art that the present invention is not limited to the examples illustrated and/or described above.

Claims (20)

- 29 - Claims 1. Mobile robot (1) comprising: - a motor drive unit; - A navigation system (4) coupled to the motor drive unit to control a movement of the robot (1) in a geographical area (9); characterized in that the robot (1) further comprises: - an electronic unit (2): e comprising a probe (3) capable of interacting with a wet portion of the geographical area (9) consisting of a body of water, e configured to generate a signal (5) from an interaction of the probe (3) with the wet portion, e coupled to the navigation system (4) to transmit the signal (5) to it; and in that the navigation system (4) is capable of modifying the movement of the robot (1) when the signal (5) is transmitted to the navigation system (4) by the electronic unit (2). 2. Robot (1) according to the preceding claim, characterized in that the probe (3) comprises a pair of electrodes (31, 32) having a potential difference which are arranged to come into electrical contact when the robot (1) moves to the level of the wet portion. 3. Robot (1) according to the preceding claim, characterized in that the pair of electrodes (31, 32) is at least partially formed of two metal cables (35) extending at a distance (d) from one of the another, each of which comprises a lower extremal segment (36) arranged to come into electrical contact with the wet portion. - 30 - 4. Robot (1) according to the preceding claim, wherein each cable (35) has a spare segment (37) able to allow replacement of the lower extremal segment (36). 5, Robot (1) according to any one of the two preceding claims, in which each cable (35) is made at least partially of stainless steel, and is of tubular shape with a section diameter of less than 5 millimeters. 6. Robot (1) according to any one of the preceding claims, further comprising: - a front end (11) and a rear end (12), the front end (11) being arranged to precede the rear end ( 12) in a main direction of movement (S), along a direction of movement (D) of the robot (1); wherein the probe (3) is arranged at the front end (11) of the robot (1). 7. Robot (1) according to the preceding claim, also comprising a deflector (6) arranged at the front end (11) of the robot (1) having a front face (61) oriented mainly towards the front end (11 ) of the robot (1) and a rear face (62) oriented mainly towards the rear end (12) of the robot (1), the probe (3) being mechanically coupled to the deflector (6), and arranged on the rear face ( 62) of it. 8. Robot (1) according to any one of claims 6 or 7, further comprising: - wheels (71, 72) mechanically coupled to the motor drive unit to support and/or steer the robot in the area geographical (9), - 31 - and comprising at least one drive wheel (72); wherein the probe (3) is aligned with the drive wheel (72) along the direction of movement (D) of the robot. 9, Robot (1) according to the preceding claim, in which the probe (3) overhangs a support plane (P) of the wheels (71, 72) with a height (h) of between 5 and 15 millimeters. 10. Robot (1) according to any one of claims 8 or 9, in which the wheels (71, 72) comprise: e two driving rear wheels (72) closer to the rear end (12) than to the front end (11) of the robot (1), and e a front wheel (71) closer to the front end (11) than to the rear end (12) of the robot (1); the robot (1) comprising two such similar probes (3), each being aligned with one of the rear wheels (72) along the direction of movement (D) of the robot (1), each being able to interact with the wet portion , the electronic unit (2) being configured to generate the signal (5) from an interaction of at least one of the probes (3) with the wet portion. 11. Robot (1) according to any one of claims 3, 4 or 5, or according to any one of claims 6, 7, 8 or 10 when dependent on any one of claims 3, 4 or 5, characterized in that each of the electrodes (31, 32) comprises a ballast (38) through which one of the cables (35) passes and from which the lower end segment (36) of the cable (35) protrudes, so that the latter overhangs a lower part ballast (38). - 32 - 12. Robot (1) according to the preceding claim, wherein the ballast (38) is of essentially ellipsoidal shape, each semi-axis (R) of which is at least millimeters. 5 13. Robot (1) according to any one of the preceding claims, in which: - the probe (3) is capable of interacting with the wet portion when the latter consists more generally of a portion of the geographical area (9) having a humidity level of at least a first humidity threshold, so that the electronic unit (2) generates the signal (5) from an interaction of the probe (3) with the wet portion; - The electronic unit (2) is configured to transmit the signal (5) to the navigation system (4) if the humidity level of the wet portion is at least a second humidity threshold. 14. Robot (1) according to any one of the preceding claims, in which the electronic unit (2) comprises: - a source of electrical energy (22) for the probe having an input voltage; - an electronic circuit (21) for electronically generating the signal (5) so that the latter has an output voltage lower than a maximum voltage threshold. 15. Robot (1) according to any one of the preceding claims, in which the navigation system (4) comprises: - a receiver for receiving position data from the robot (1), the control of the movement of the robot (1) taking place on the basis of position data; and - a transmitter configured to transmit the position data of the robot (1) to a remote electronic device when the signal (5) is transmitted to the navigation system (4) by the electronic unit (2), and/or - 33 - a data carrier on which the navigation system (4) is able to record the position data of the robot (1) when the signal (5) is transmitted to the navigation system (4) by the electronic unit ( 2). 16, Robot (1) according to any one of the preceding claims, in which the electronic unit (2) comprises a test unit comprising: - a measurement module similar to the probe (3), arranged similar to the probe ( 3), in the vicinity of the probe (3), so that it is able to interact similarly to the probe (3) with the wet portion; - A comparison module electronically coupled to the probe (3) and to the measurement module, and configured to perform a comparison between the interactions of the probe (3) with the wet portion and the interactions of the measurement module with the wet portion; - An alert module electronically coupled to the comparison module, and configured to emit an alert signal based on a number of consecutive interaction differences in the comparison. 17. Robot (1) according to any one of the preceding claims consisting of a robotic mower. 18. Use of the robot (1) according to any one of the preceding claims to detect and/or map bodies of water in a geographical area (9). 19. Method for moving a mobile robot (1) comprising: - a motor drive unit; - a navigation system (4) coupled to the motor drive unit to control a movement of the robot (1) in a geographical area (9); the method comprising the following steps: - 34 - (i) providing the robot (1) with an electronic unit (2): e comprising a probe (3) capable of interacting with a wet portion of the geographical area (9) consisting of a body of water, e configured to generate a signal (5) from an interaction of the probe (3) with the wet portion, e coupled to the navigation system (4) to transmit the signal (5) to it; (ii) controlling the movement of the robot (1) in the geographical area (9) by means of the navigation system (4), so as to move the robot (1) at the level of the wet portion and to create an interaction between the wet portion and probe (3); (iii) generating the signal (5) from the interaction of step (ii) by means of electronic unit (2); (iv) modifying the movement of the robot (1) in the geographical area (9) by means of the navigation system (4) on the basis of the signal (5) generated in step (iii) when it is transmitted to the navigation (4) by the electronic unit (2). 20. Method according to the preceding claim, in which: - electronic unit (2) provided in step (i) is such that the robot obtained in step (i) is according to claims 13 and 14; - the signal (5) is generated electronically in step (iii) by means of the electronic circuit (21) so that the output voltage of the signal (5) is lower than the maximum voltage threshold and proportional to the rate humidity of the wet portion; and - the second humidity threshold corresponds to a minimum voltage threshold of the signal (5); step (ii) comprising the sub-step: (ii) transmitting the signal (5) generated in step (iii) to the navigation system (4) by means of the electronic unit (2) when the voltage of signal output (5) is greater than the minimum voltage threshold.