FLOOR PROCESSING ROBOT SYSTEM AND METHOD FOR RETURNING AN AUTONOMOUSLY DRIVING FLOOR PROCESSING ROBOT

Description

[0001] The invention generally relates to a soil cultivation robot system comprising a conductive loop wire, which serves to delimit the area to be cultivated and to guide the robot back, and an autonomously moving soil cultivation robot for cultivating the area delimited by the loop wire. In particular, the invention can be configured as a robotic mower system.

[0002] Robotic lawnmower or soil cultivation systems that work an area bounded by a boundary wire in a more or less random direction without an external navigation system, and that detect the boundaries of the area to be worked by detecting the boundary wire—more precisely, by detecting a continuous or alternating magnetic field generated by the boundary wire—are well known. The boundary wire typically also serves to guide the robot back to a base station from any point along the wire. Since such robots are usually powered by electric motors, the robot's energy storage can be recharged at the base station. Furthermore, the robot can be parked there, possibly protected by the base station.

[0003] The invention described here relates to soil cultivation robots, in particular mowing robots, which travel over an area to be cultivated which is bounded at the edges by a loop cable, wherein the robot is controlled exclusively according to the random principle and without supplementary localization technology, such as radio triangulation, satellite navigation or inertial navigation.

[0004] A problem with such systems is that the robot is guided along the same path on every return journey and usually works on this path simultaneously. This creates a distinct track along the loop wire, which differs undesirably from the rest of the worked area. Furthermore, this type of return journey leads to the robot randomly traveling relatively long distances if it encounters the loop wire at an inconvenient entry point. This necessitates initiating a return to the base for recharging even when a relatively large energy reserve remains. Moreover, the return journey and recharging process takes a relatively long time overall. While control methods exist that circumvent these problems using local or global navigation techniques, these methods have the disadvantage of being complex and expensive.

[0005] From the publication DE 698 29 411 T2, a robotic lawnmower system with the features of the preamble of claim 1 and a method for returning an autonomously driving robotic lawnmower with the features of the preamble of claim 23 are known.

[0006] Reference is also made to the publications WO 2022 / 080596 A1, US 9,903,947 B2, US 2013 / 0211647 A1 and WO 2022 / 134735 A1.

[0007] It is therefore an object of the invention to optimize a soil cultivation robot system with a current-conducting loop wire for area limitation and return of the robot without the use of a navigation system in such a way as to avoid the disadvantages described above, such as track avoidance and reduction of the return time.

[0008] This problem is solved by the features of the independent patent claims. Advantageous embodiments of the invention are the subject of dependent claims.

[0009] The inventors have recognized that it is possible, particularly without a local or global navigation system, a radio-based homing system, a radio-based triangulation system, or an inertial navigation system, to improve the guidance of a soil cultivation robot, especially a robotic lawnmower – generally also called a robot – by means of a guide wire, by altering the intensity of the magnetic field emanating from the guide wire at suitable points. The strength of the magnetic field can be either weakened or strengthened.

[0010] Preferably, the magnetic field can be manipulated directly by the spatial arrangement of the loop wire, preferably in the form of turns introduced into the current flow of the loop wire in a confined space. For example, this can be achieved by appropriate laying techniques for the loop wire, which create the desired type and number of current-carrying turns and thus generate a locally limited change in the magnetic field in the immediate vicinity of the loop wire. To enhance the effect of the wire turns, a ferromagnetic core can additionally be introduced into the turns.

[0011] Alternatively, the magnetic field can also be manipulated by inserting preferably prefabricated passive electrical or electronic components, in particular inductors made of magnetic coils with and without a metal core, into the loop wire. The loop wire must be electrically connected to the component in such a way that the current flow, at least predominantly, occurs through the inserted component, especially the inserted magnetic coil. A ground stake, for example, can also be used as the metal core around which the loop wire is wound.

[0012] Alternatively or additionally, a capacitor can be inserted, the size of which can be chosen according to the frequency and current in the loop wire so that it has no or little damping effect on the applied alternating current.

[0013] According to the invention, the manipulations described herein cause a locally limited change in the magnetic field generated by the loop wire, which leads to typical signal changes in the measured magnetic field signal when the robot moves along the loop wire. The robot measures the magnetic field signal itself to detect its approach to the loop wire and guide it along the loop wire. Changes in this magnetic field signal also occur at other points along the loop wire, for example, at corners of the loop. However, it is possible to design the signal changes introduced for marking purposes in such a way that they are clearly distinguishable from the other signal changes. In particular, encoding that can be uniquely recognized by the robot can also be achieved through several successive signal changes generated by a series, parallel, or mixed connection of individual marking elements.It is also possible to distinguish between several manipulations or markings of the magnetic field.

[0014] In principle, such a typical signal pattern of the magnetic field on the boundary wire, altered by markings, can be detected directly by the sensors on the robotic lawnmower, i.e., without prior training, but pre-programmed. Preferably, the robot is trained on the markings present in the boundary wire with their respective typical signal patterns through a calibration process; these patterns and / or characteristic parameters of these patterns are stored and are available for subsequent detections.

[0015] Furthermore, each typical signal pattern and / or its parameter set can be linked to one or more predetermined actions that are executed after the respective signal pattern is detected.

[0016] It should be noted that the terms "predetermined action" and "after detection" can encompass different action variants with varying delay times, each within a predefined framework. This applies, for example, to the slightly variable delay and angle for the robot turning away from the guide wire, thus preventing tracks from being left behind by repeatedly traversing or processing the same path.

[0017] It is further noted that, within the scope of the invention, "executing an action" can also be understood to mean that an action following the robot's standard behavior is suppressed. For example, a trigger can be set at a specific point so that, if the robot is on its way back to the base station, it ignores the bend in the guide wire and continues along the existing path for a certain time or distance until it encounters the guide wire again, which it then follows. This can, for example, shorten a kind of sagging in the area to be worked.

[0018] In operation, the robot will therefore recognize these pre-programmed or learned signal patterns via an algorithm and then perform at least one action associated with them.

[0019] One such typical action is, for example, the robot rotating into the area bounded by the loop wire. If the loop wire is always traversed clockwise, this corresponds to a turn to the right.

[0020] By appropriately positioning the electromagnetic marker in the boundary wire, the robot can be made to rotate towards the base station or towards the opposite boundary loop of the field. The robotic mower thus moves in this direction, shortening its path to the base and avoiding the disadvantages of the prior art described above.

[0021] The invention also includes the fact that the triggered course change angle is variably adjustable or can be defined as varying randomly or in a targeted manner within predefined angular ranges. The same applies to the reaction time or distance after the detection of a typical signal pattern serving as a marker when traversing the loop wire.

[0022] Based on these principles, the inventors propose a soil cultivation robot system, in particular a robotic mower system, which has the following features: A surface boundary device comprising: -- a current-conducting loop wire, which serves to delimit an area to be processed and to guide the robot back, -- a base station for power supply, in particular also for the loop wire, wherein the loop wire generates a magnetic field with an intensity when power is supplied, -- wherein the loop wire has at least one means for locally changing the intensity of the generated magnetic field at at least one position along its length, -- an autonomously moving soil cultivation robot for processing the area bounded by the loop wire comprising: -- means for detecting the intensity of the magnetic field along the loop wire, -- means for detecting a signal profile of a changing intensity of the magnetic field during movement along the loop wire, -- a control system for the soil cultivation robot, which is configured toto trigger at least one predefined activity based on a positive detection of a predefined signal pattern of the magnetic field intensity during movement along the loop wire, wherein the specified activity during movement along the loop wire is at least one control action of the soil cultivation robot, with which the soil cultivation robot terminates the movement along the loop wire by steering in a specified direction.

[0023] In other words, this activity or action of ending the movement along the grinding wire means that, despite the grinding wire continuing unchanged in a straight line or with a continuing curve, the soil cultivation robot executes a change of direction at a predetermined angle, or alternatively, despite a change in the direction of the grinding wire, it refrains from changing direction, i.e., it does not follow this change of direction and continues straight ahead or is controlled.

[0024] These measures now make it possible to initiate an intensity profile at one or more points along the loop wire by changing the magnetic field as the robot moves along it. The robot can then recognize this profile as a typical pattern and initiate appropriate actions. A particular advantage is that existing robots equipped with loop wire detection can be upgraded to this technology via a simple software update. However, this upgrade also requires manipulating the loop wire at the desired marking points.

[0025] In a specific variant of the soil cultivation robot system, it is proposed that the robot's control system be configured to execute different activities in response to different detected signal patterns, with each activity assigned to that specific signal pattern. For this purpose, a LUT (look-up table) can be integrated into the robot's control system. This LUT contains different signal patterns and / or their typical parameters for differentiating between them. One or more associated actions can then be stored for each of these different signal patterns, which the robot's control system executes upon detection of the signal pattern.

[0026] Preferably, the control system of the soil cultivation robot can be configured so that, upon detecting a predefined signal pattern in the intensity of the magnetic field while moving along the guide wire, the robot executes a change of direction at a predefined angle. This predefined angle can be absolute, or a predefined algorithm can be defined that causes random or systematic changes in the angle within a specific angular range. This prevents the formation of tracks caused by repeatedly traversing the same path.

[0027] Furthermore, the control system of the soil cultivation robot can also be designed to execute different changes of direction at a predetermined angle, depending on the characteristics of the signal waveform. Thus, the markings are coded by different induced signal waveforms, with each code being assigned an individually predefined angle, which may be variable within certain limits.

[0028] In a further advantageous embodiment, it is proposed that the control system of the soil cultivation robot is designed to execute the change of direction towards the interior of the area to be cultivated, i.e., towards the opposite side of the loop wire.

[0029] Preferably, the control system of the soil cultivation robot is configured to execute the change of direction towards the base station, thus shortening the return path. This also requires that the marker on the boundary wire be positioned spatially in relation to the individually shaped area to be cultivated, thereby enabling a shortened return path for the robot.

[0030] Since the signal pattern of the magnetic field along a loop wire laid individually around a work surface is subject to large and not necessarily predictable variations, it is particularly advantageous if the soil cultivation robot is designed to learn and store at least one signal pattern of the magnetic field intensity during movement along the loop wire that initiates a predefined action, preferably together with a specific associated action. This allows the individual characteristics and arrangement of marking elements in the loop wire to be taken into account under the respective environmental conditions, and the error rate in recognizing the respective signal pattern of one or more markings to be significantly reduced.

[0031] In a further advantageous embodiment of the soil cultivation robot system, it is proposed that the loop wire of the area boundary device has several means for changing the intensity of the magnetic field distributed along its length.

[0032] Furthermore, the means for changing the intensity of the magnetic field on the loop wire can be divided into at least two groups and arranged on the loop wire in such a way that each group generates a unique signal profile of the intensity of the magnetic field when moving along the loop wire and thus an individual coding.

[0033] In the soil cultivation robot system according to the invention, at least one means for changing the intensity of the magnetic field on the loop wire can be selected to be an air coil with a plurality of turns integrated in the loop wire as in the circuit.

[0034] Furthermore, at least one means of changing the intensity of the magnetic field on the loop wire can be a coil integrated into the loop wire as part of the circuit, with a large number of turns and an additional ferromagnetic core. In the simplest version, this can be achieved by wrapping a ground stake with several turns of the loop wire.

[0035] Furthermore, a change in the intensity of the magnetic field at the loop wire can also be achieved and detected by a capacitor integrated into the current loop. However, this requires that the current flowing the magnetic field be alternating current (AC). With direct current (DC), a capacitor would block the current flow.

[0036] If a weakening of the magnetic field is to be achieved, a shield can be arranged over a section of the loop wire.

[0037] It should be noted that the soil cultivation robot system according to the invention is primarily a system that relies exclusively on the use of the guide wire for orientation and is therefore free of navigation systems that are not based on a guide wire. The system thus does not have radio positioning devices such as satellite navigation, GPS, GLOSSNAS, Bluetooth navigation, radio triangulation devices, radio homing systems, or inertial navigation systems.

[0038] Within the scope of the invention, the inventors also propose the use of an autonomously driving soil cultivation robot, in particular a mowing robot, for use with an area boundary device with a loop wire having at least one means for locally changing the intensity of the magnetic field on the loop wire, with: Means for detecting the intensity of the magnetic field along the loop wire, means for detecting a signal profile of a changing intensity of the magnetic field during movement along the loop wire, and a control system for the soil cultivation robot, which is configured to trigger at least one predetermined activity based on a positive detection of a predetermined signal profile of the intensity of the magnetic field during movement along the loop wire, wherein the predetermined activity during movement along the loop wire includes at least one control action of the soil cultivation robot, with which the soil cultivation robot terminates the movement along the loop wire by steering in a predetermined direction.

[0039] The soil cultivation robot according to the invention can have the robot-related features described above.

[0040] The invention also describes the use of an area limitation device for use with an autonomously driving soil cultivation robot, which Means for detecting the intensity of a magnetic field along a loop wire, means for detecting a signal profile of the changing intensity of the magnetic field during movement along the loop wire, and a control system for the soil cultivation robot, which is configured to trigger at least one predetermined activity based on a positive detection of a predetermined signal profile of the intensity of the magnetic field during movement along the loop wire, the area boundary device comprising: a current-conducting loop wire, which serves to delimit an area to be cultivated and to guide the robot back, a base station for power supply, in particular also for the loop wire, wherein the loop wire, when powered, generates a magnetic field with an intensity ofwherein the loop wire has at least one means for locally changing the intensity of the magnetic field occurring at the loop wire at at least one position along its length, which causes at least one predetermined activity of the soil cultivation robot when moving along the loop wire, with which the soil cultivation robot terminates its movement along the loop wire by steering in a predetermined direction.

[0041] Accordingly, the area limiting device can have the loop wire-related features described above.

[0042] Furthermore, a device for locally changing the intensity of the magnetic field generated by a loop wire is described, comprising: a plastic sheath enclosing an insulated wire, a cutting / insulating element integrated into the sheath for cutting a loop wire running through the sheath, two stripping / connecting elements integrated into the sheath and each arranged laterally to the cutting / insulating element, a coil integrated into the sheath, wherein a conductive connection exists to each end of the coil with each of the two stripping / connecting elements.

[0043] With such a device, a coil can be easily inserted into a loop wire – similar to how so-called wire taps are clipped into an existing cable. The loop wire is placed into the device, then preferably simultaneously, the loop wire is cut by actuating the device, and the remaining ends of the loop wire are connected to the ends of the coil inside the device. Pliers can be used for this purpose, which actuate the corresponding cutting and connecting elements.

[0044] The coil can also advantageously have a ferromagnetic core.

[0045] Furthermore, a ground nail for attaching a loop wire to the edge of an area to be worked by a soil cultivation robot is also described, wherein the ground nail consists at least partially of ferromagnetic metal and a coil with a plurality of turns encloses at least a part of the ferromagnetic metal, wherein the coil ends can be connected to the loop wire in such a way that a current flow through the loop wire is directed over the coil of the ground nail.

[0046] Furthermore, a method for returning an autonomously moving soil cultivation robot is proposed, the area to be cultivated of which is bounded by a loop wire and which is returned to a base station using the loop wire and a magnetic field generated by the loop wire, wherein the robot detects the intensity of the magnetic field at the loop wire and, based on the recognition of a predefined typical intensity profile during movement along the loop wire, a predefined action is triggered, which, during the movement of the soil cultivation robot along the loop wire, triggers at least one control action of the soil cultivation robot, with which the soil cultivation robot ends the movement along the loop wire by steering in a predefined direction.

[0047] The detection of a typical intensity profile can be achieved, for example, by considering given parameters such as the steepness of the signal increase, exceedance of a minimum value relative to a running average of previous intensities, etc. Alternatively, pattern recognition methods, possibly also employing AI techniques, can be used.

[0048] In a preferred embodiment of the method, it can also be required that, in addition to recognizing a predefined typical intensity profile, at least one predefined operating condition must be present during movement along the loop wire to execute the at least one action. For example, a pivot to the inside of the area enclosed by the loop wire can only occur if the robot is on its way back to the base station.

[0049] Furthermore, it is particularly advantageous if the specified intensity profile has been previously programmed or learned. This allows the system to optimally adjust to specific characteristics that depend on the individual routing of the loop wire.

[0050] The process can also be designed in such a way that different intensity profiles trigger different actions.

[0051] In particular, at least one action may consist of the robot turning at a predetermined angle from the loop wire to the opposite section of the loop wire or to the base station at a predetermined time after detecting a specific intensity profile.

[0052] At least one action can also consist of the robot, after detecting a certain intensity profile, moving laterally offset from the loop wire at a predetermined angle and continuing parallel to the loop wire.

[0053] It is also pointed out that an action can also consist of refraining from making a change. For example, by not following the loop wire after a mark, even though the loop wire changes direction.

[0054] The invention is described in more detail below with reference to preferred embodiments and the figures, whereby only the features necessary for understanding the invention are shown.

[0055] They show in detail: FIG 1: a schematic representation of a known soil cultivation robot system, FIG 2: signal curve as a function of time, FIG 3: signal curve with unique markings, FIG 4: a schematic representation of a soil cultivation robot system according to the invention in a first embodiment, FIG 5: a schematic representation of a soil cultivation robot system according to the invention in a further embodiment, and FIG 6: a schematic representation of a soil cultivation robot system according to the invention in yet another embodiment.

[0056] The core concept of the invention is to locally manipulate the magnetic field F generated by the magnetic field wire generated by the magnetic field wire, such that the resulting local change in the magnetic field is recognized by the robot R with its magnetic field detector D as a marker M, M1-M5. The robot is equipped, in a known manner, with a magnetic field detector D and a controller with a processor and memory for storing program code and data, such as a LUT (Launch User Table). The program code is executed during operation and also performs the method according to the invention.Compared to the well-known robot with loop wire technology, the robot differs essentially in the stored data regarding marker recognition and the program code that executes the marker recognition and the actions triggered by markers.

[0057] The Figure 1This illustrates the familiar situation of a soil cultivation robot system, here with a robotic lawnmower R, which orients itself solely using a boundary wire W surrounding the area F to be cultivated. When the robot R needs to find its way back to the base station from a random location within the area F, either because it has completed its work or because its battery is largely depleted, it maintains its current course until it eventually reaches the boundary wire and detects it with its detector, a magnetic field sensor. It then turns in a predetermined direction, here to the right, and, lacking better information, follows the boundary wire W along its path T until it reaches the base station. Given the fundamentally random behavior of the robotic lawnmower R, very long distances may be required, although on average, it is likely to cover approximately half the perimeter of the area F.This results in the disadvantages described above, such as track formation and high energy consumption for the return path, which must be taken into account in the energy management of the robot R.

[0058] Considering the intensity of the signal at detector D, a signal profile I(s) is obtained over the distance s traveled by the robot R along the loop wire W, which in turn is a function of time, as described in the Figure 2 This is illustrated as an example. It is easy to see that the signal I(t) exhibits relatively high fluctuations.

[0059] Due to legal regulations regarding the EMC behavior of a loop wire, it is not easily possible to induce arbitrarily strong magnetic peaks on the loop wire that are clearly above the intensity level of the loop wire's magnetic field and would be easy to detect. According to the invention, intensity maxima are therefore used for marking, the level of which is relatively close to the partially achieved intensities of a loop wire without magnetic marking. To detect such small intensity increases, bias smoothing, for example by calculating moving averages, and / or pattern recognition methods are applied. In the Figure 3Typical signal waveforms are shown with unambiguous markers M1 and M2. For the coding of multiple distinguishable markers, reference is made to generally known coding methods. It is particularly advantageous if the robot R is trained on the actual signal waveform using markers that are actually present in the field.

[0060] If additional inductors are inserted into the loop to boost the signal at a specific point, this initially introduces an interference point into the overall system. The overall loop signal decreases, and the maximum field strength F also becomes theoretically smaller. Therefore, relatively small inductors in the range of approximately 10 µH to 100 µH are preferably used.

[0061] In order to recognize the changed signal patterns caused by the coils used, the robot R should be taught the actual signal pattern, because the signal pattern is different for each installation or loop length.

[0062] For such an exemplary calibration, the robot can be positioned so that it approaches the loop at least one meter in front of the signal to be measured. The robot then performs a measurement of the loop signal at regular time or distance intervals, for example, every 100 ms. These measurements are stored in a predetermined, continuous sequence, ensuring that a consistent segment of the loop signal waveform is always stored in memory. Smoothing algorithms can then be executed on these stored values, eliminating signal distortions caused by changing bias and leading to improved recognition of typical signal waveforms.

[0063] In particular, typical parameters such as signal maximum or minimum relative to the bias, peak width, integral values, average values, etc., can be determined and compared with learned values ​​to identify specific signal patterns. These values ​​can then be permanently stored as reference parameters in the robot's memory during calibration and linked to a desired action.

[0064] As the robot searches for the station and travels along the loop cable, these typical parameters can be continuously calculated and compared with the stored reference parameters. If a match is found within predefined tolerance ranges, this can be interpreted as a positive detection of a specific marker, and the corresponding action can be executed.

[0065] In addition to the method described above, other known signal and pattern recognition methods can also be used.

[0066] Besides recognizing a marking and distinguishing between different markings, the effect of the invention also depends significantly on where the marking is positioned within the loop wire for a given area and what action the robot performs on it. It is difficult to give a general rule for the optimal placement of one or more markings in a loop wire, as the optimal position of the markings and the corresponding path-shortening actions depend heavily on the individual shape of the area to be processed and any obstacles that may be present. In the Figures 4 to 6 However, several variations of different marker positions and different actions associated with the markers are shown. In all examples, it is assumed that the robot R travels along the loop wire W in a clockwise direction.

[0067] The Figure 4Figure 1 shows a surface F to be processed by a robot R, which is enclosed by a loop wire W. The contour of surface F is identical to the surface F from the diagram. Figure 1 and contains a larger first sub-area on the right and a smaller second sub-area in the upper left in the form of a protrusion, which are connected to each other at the top via a corridor. The loop wire W has two identical markings M, each located on the left ascending branch of the loop wire W. The positioning and direction of travel of the robot R also correspond to the beginning of its path T. Figure 1However, as soon as the robot R encounters one of the markings M on its path T, it will recognize it and execute the stored action: a 90° right turn away from the loop wire W to the opposite side of the surface F, where it will rejoin the loop wire W and proceed clockwise along the loop wire W to the base station B. Specifically, the selected path T (dashed line) of the robot R is shown, which, due to its positioning and direction of travel, Figure 1 arises.

[0068] All other positioning and travel directions that lead to initial contact of the robot R with the loop wire W in front of one of the markings M also result in a correspondingly shortened return path of the robot R to the base station, thus reducing track formation. In this example, it is assumed that all markings trigger the same action of a right turn. To further minimize track formation, a different reaction time or a different reaction path for the robot R can be programmed for the action performed. For example, a counter for the number of turns or a random number can be used. Furthermore, different turning angles, for example in the range of 90° + / - 10°, can be controlled each time. Combinations of these methods are also within the scope of the invention.

[0069] In the Figure 5is again the same contour of a surface F to be processed as in the Figure 1 and 4 As shown, however, the base station is not located at the bottom center of the page, but rather at the top right third. The starting position and direction of travel of the robot R have also been changed. The guide wire W now contains a first marker M1, assigning a first action in the form of an acute right turn, and a second, different marker M2, assigning a second action. The second action consists of the robot ignoring the guide wire for a predetermined time or distance and continuing on its current course until it re-enters the guide wire and then follows it again.

[0070] An example path T of the robot R, with the initial situation shown, is again depicted as a dashed line. On its path towards the lower right (approximately 4 o'clock), the robot R encounters the guide wire W, is then guided clockwise to the next marker M1, and there is directed at an acute angle to the opposite guide wire W, thus shortening a significant portion of the return path. From there, it continues along the guide wire W to the next marker M2. This marker is located shortly before the turn to the second section and causes the robot R to continue straight ahead to the opposite side of the corridor, disregarding the change in direction of the guide wire W. There, the robot R again detects the guide wire W and turns right towards the base station B.Overall, this arrangement of markings and associated actions significantly alters the return path T of the robot R compared to a situation from the . Figure 1 The absence of markings significantly reduces the distance, saving energy and minimizing rutting. Figure 6 Figure 1 shows further variations of markings M1 to M5 with different assigned actions at various positions in the loop wire W, where the base station B is located in the second sub-area. Markings M1 to M5 each cause the robot R to swivel away from the loop wire W at different angles. These angles are chosen to minimize the remaining travel distance back to the base station B while simultaneously ensuring that minor inaccuracies in the travel path still reliably lead to a catch line in the loop wire W.

[0071] Overall, the invention relates to a soil cultivation robot system comprising: a surface boundary device with: a current-conducting loop wire, a base station for power supply, wherein the loop wire, when powered, generates a magnetic field with an intensity and has at least one means for locally changing the intensity of the generated magnetic field at at least one position along its length, an autonomously moving soil cultivation robot with: means for detecting the intensity of the magnetic field along the loop wire, means for detecting a signal profile of a changing intensity of the magnetic field during movement along the loop wire, a control system for the soil cultivation robot, which is configured toThe invention relates to triggering at least one predetermined activity based on the positive detection of a predefined signal pattern in the intensity of the magnetic field during movement along the loop wire. Furthermore, the invention relates to a method for returning the soil cultivation robot. Reference symbol list

[0072] B Base station DD Detector F Area to be processed M, M1-M5 Markings or group of markings P Control unit with processor, memory and program code R Soil cultivation robot, mowing robot, robot W Looping wire T Robot's travel path

Claims

1. Ground maintenance robot system, in particular mowing robot system, having: 1.

1. an area delimiting device with: 1.1.

1. a current-conducting loop wire (W), which serves for delimiting an area (F) to be maintained and for returning a ground maintenance robot (R), 1.1.

2. a base station (B) for supplying power, in particular also to the loop wire (W), wherein the loop wire (W) forms a magnetic field with an intensity (I) when there is a power supply, 1.1.

3. wherein the loop wire (W) has at at least one position over its length at least one means (M) for locally changing the intensity of the magnetic field generated, 1.

2. an autonomously driving ground maintenance robot (R) for maintaining the area (F) bounded by the loop wire (W), with: 1.2.

1. means (D) for detecting the intensity of the magnetic field along the loop wire, 1.2.

2. means for detecting a signal profile of a changing intensity (I) of the magnetic field when there is a movement along the loop wire (W), 1.2.

3. a controller (P) of the ground maintenance robot (R), which is designed to initiate at least one predetermined activity on the basis of a positive detection of a predetermined signal profile of the intensity (I) of the magnetic field when there is a movement along the loop wire (W), characterized in that 1.2.

4. the predetermined activity in response to the movement along the loop wire (W) is at least one controlling action of the ground maintenance robot (R), by which the ground maintenance robot (R) ends the movement along the loop wire (W) by providing control in a predetermined direction.

2. Ground maintenance robot system according to the preceding claim, characterized in that the controller of the ground maintenance robot (R) is designed to initiate the predetermined activity only when a predetermined operating situation exists.

3. Ground maintenance robot system according to one of the preceding claims, characterized in that the controller (P) of the ground maintenance robot (R) is designed to perform in response to various detected signal profiles other activities in each case, assigned to each signal profile.

4. Ground maintenance robot system according to one of the preceding claims, characterized in that the ground maintenance robot (R) is designed to learn at least one signal profile of the intensity (I) of the magnetic field when there is a movement along the loop wire (W) that initiates a predetermined action and to store it in the system, preferably to store it together with a specific assigned action.

5. Ground maintenance robot system according to one of the preceding claims, characterized in that the loop wire (W) of the area delimiting device has distributed over its length multiple means (M) for changing the intensity of the magnetic field.

6. Ground maintenance robot system according to the preceding claim 5, characterized in that the means (M) for changing the intensity (I) of the magnetic field on the loop wire (W) are divided into at least two groups, and arranged on the loop wire (W) in such a way that each group produces a bijective signal profile of the intensity (I) of the magnetic field when there is a movement along the loop wire (W).

7. Ground maintenance robot system according to one of the preceding claims, characterized in that at least one means (M) for changing the intensity (I) of the magnetic field on the loop wire (W) is an air coil which is integrated in the loop wire (W) and has a multiplicity of turns.

8. Ground maintenance robot system according to one of the preceding claims, characterized in that at least one means for changing the intensity of the magnetic field on the loop wire (W) is a coil which is integrated in the loop wire (W) and has a multiplicity of turns and a ferromagnetic core.

9. Ground maintenance robot system according to one of the preceding claims, characterized in that at least one means (M) for changing the intensity (I) of the magnetic field on the loop wire (W) is a capacitor incorporated in the current loop.

10. Ground maintenance robot system according to one of the preceding claims, characterized in that at least one means (M) for changing the intensity (I) of the magnetic field on the loop wire (W) is a shield for the loop wire (W) over a section of the loop wire.

11. Use of the autonomously driving ground maintenance robot, in particular mowing robot, in a ground maintenance robot system according to one of the preceding claims 1 to 10.

12. Use of the area delimiting device in a ground maintenance robot system according to one of the preceding claims 1 to 10.

13. Method for returning an autonomously driving ground maintenance robot (R), the area that is to be maintained by the robot being delimited by the loop wire (W) and the robot being returned to a base station (B) by using the loop wire (W) and a magnetic field generated by the loop wire (W), characterized in that the ground maintenance robot (R) detects the intensity (I) of the magnetic field at the loop wire (W) and, on the basis of a detection of a predetermined typical intensity profile during the movement along the loop wire (W), initiates a predetermined action which, in response to the movement of the ground maintenance robot (R) along the loop wire (W), initiates at least one controlling action of the ground maintenance robot (R), by which the ground maintenance robot (R) ends the movement along the loop wire (W) by providing control in a predetermined direction.

14. Method according to the preceding claim 13, characterized in that, for performing the at least one action, in addition to the detection of a predetermined typical intensity profile, an operating condition which is at least also predetermined during the movement along the loop wire (W) must be satisfied.

15. Method according to one of the preceding claims 13 to 14, characterized in that the predetermined intensity profile has previously been learned.

16. Method according to one of the preceding claims 13 to 15, characterized in that different intensity profiles initiate different actions.