Method of using wire-guided robotic lawnmowers

Abstract

A method for navigating a robotic lawnmower (2) via a guide wire (8). The robotic lawnmower (2) includes at least one sensor (12, 14). The method includes detecting (S101) at least one signal from the guide wire (8) via at least one sensor (12, 14), controlling (S102) the robotic lawnmower (2) to align with the guide wire (8), controlling (S103) the robotic lawnmower (2) to rotate a portion (8a) of the guide wire (8) by a certain angle, controlling (S104) the robotic lawnmower (2) to increase the distance between the robotic lawnmower (2) and the guide wire (8) by traveling a displacement distance based on a random distance value, measuring (S105) the signal level of at least one signal from the guide wire (8) via at least one sensor (12, 14), and controlling (S106) the robotic lawnmower (2) to follow the guide wire (8) based on the measured signal level.

Description

Technical Field

[0001] The present invention generally relates to a method for navigating a robotic lawnmower along a guide wire (e.g., returning to a charging station) when the battery of the robotic lawnmower needs to be charged. Background Technology

[0002] As is well known, robotic lawnmowers are also called self-propelled lawnmowers. These robotic lawnmowers are equipped with rechargeable batteries. When the remaining power in the battery drops below a certain level, the robotic lawnmower is configured to return to a charging station to recharge the battery. There are many ways to control a robotic lawnmower to return to a charging station. One common method is that when the robotic lawnmower receives a command to return to the charging station, it continues to move until it detects a boundary line, and then follows the boundary line to reach the charging station located somewhere along the boundary line.

[0003] Another method is to use guide lines to control the robotic lawnmower to follow the guide lines back to the charging station. Compared to returning to the charging station along the boundary lines, using guide lines can generally shorten the return time and speed up the return process. Guide lines also facilitate the robotic lawnmower's passage through narrow passages.

[0004] One problem with controlling a robotic lawnmower using guide lines or boundary lines is that the robotic lawnmower leaves tracks on the lawn when it travels the same path multiple times. Patent WO 2019 / 183907 A1 successfully solves this problem by detecting signals from a guide line using at least one sensor and following the guide line at a certain distance, wherein the distance corresponds to a given signal strength sensed by the at least one sensor, and wherein the control unit randomly selects the signal strength each time a guide line signal is detected.

[0005] Other robotic lawnmowers can apply a range of signal values, and each time the robotic lawnmower returns to the charging station, it can choose a random one from these ranges. This simplifies the control of the robotic lawnmower, but generally has the disadvantage of randomly reducing the actual path of the robotic lawnmower. Therefore, over time, tracks on the lawn may still form at some points and / or in some settings.

[0006] Additionally, signal levels typically depend on the length of the corresponding wire and can vary in different locations, such as smaller or larger gardens. Furthermore, signal levels may differ depending on whether the user decides to lay the wire above ground or bury it underground. Therefore, in practice, users may need to adjust the robot lawnmower settings so that it can navigate relatively narrow passages without creating tracks. Summary of the Invention

[0007] The purpose of this invention is to provide a method for navigating a robotic lawnmower using a guide wire, and this method reduces the risk of leaving marks in a simple and reliable manner.

[0008] To achieve the above objectives, the present invention provides a method for navigating a robotic lawnmower. The robotic lawnmower is navigated via a guide wire. For example, when the robotic lawnmower needs charging, it is controlled to return to a charging station. The robotic lawnmower includes at least one sensor. The method includes detecting at least one signal from the guide wire via the at least one sensor. The method also includes controlling the robotic lawnmower to align itself with the guide wire. Subsequently, the method provides to control the robotic lawnmower to rotate an angle relative to a portion of the guide wire. Subsequently, the method includes controlling the robotic lawnmower to travel a displacement distance based on a random distance value to increase the distance between the robotic lawnmower and the guide wire. Then, the signal level of the at least one signal from the guide wire is measured via at least one sensor of the robotic lawnmower. Subsequently, the method includes controlling the robotic lawnmower to follow the guide wire based on the measured signal level.

[0009] This is based on the idea of ​​using an odometer to adjust the random distance value to the guide wire, and applying only the signal level to maintain this distance. Therefore, environmental changes or different signal levels no longer necessarily have a direct impact on the assumed distance of the robotic lawnmower. Furthermore, the elimination of the need to apply a signal level range increases the randomness of the distance, further reducing the risk of trajectory formation.

[0010] As an exemplary embodiment of the present invention, a method for controlling a robotic lawnmower to travel a certain displacement distance based on a random distance value includes counting and / or measuring the number of revolutions of a rotatable component of the robotic lawnmower (e.g., at least one wheel of the robotic lawnmower) over time. This allows for setting the random distance value with higher precision.

[0011] As another exemplary embodiment of the present invention, a method for controlling a robotic lawnmower to align with a guide wire includes controlling the robotic lawnmower to pass through the guide wire at a predetermined distance, which may be referred to as the crossing distance, and optionally, determining the direction by measuring the polarity of at least one signal from the guide wire using at least one sensor, and optionally, controlling the robotic lawnmower to rotate in the determined direction. This allows for very quick and accurate determination of the direction the robotic lawnmower needs to turn. For example, the determined direction could be the direction of a charging station.

[0012] As an exemplary embodiment of the present invention, a robotic lawnmower includes at least two sensors, and a method for rotating the robotic lawnmower in a determined direction includes rotating the robotic lawnmower relative to a guide wire until the two sensors detect at least one signal of opposite polarity in the guide wire. This allows the correct direction to be found in a simple, accurate, and fast manner.

[0013] As an exemplary embodiment of the present invention, a method for controlling a robotic lawnmower to align with a guideline includes: controlling the robotic lawnmower to follow the guideline along a first direction until a straight portion of the guideline is detected, and optionally, in response to detecting the straight portion of the guideline, controlling the robotic lawnmower to follow the guideline along a second direction opposite to the first direction. In this way, the robotic lawnmower positions itself in front of the straight portion of the guideline, thereby accurately initializing a random distance between the robotic lawnmower and the guideline in a predictable manner.

[0014] As an exemplary embodiment of the present invention, a method for controlling a robotic lawnmower to follow a guide along a second direction includes traveling a distance based on a random distance value, which may be referred to as the reverse distance. In other words, the random distance value is used twice, first to calculate the reverse distance and second to calculate the displacement distance.

[0015] As an exemplary embodiment of the present invention, the random distance value is multiplied by a first factor to calculate the reverse distance, and the random distance value is multiplied by a second factor to calculate the displacement distance. The first factor and the second factor may be the same or different.

[0016] As an exemplary embodiment of the present invention, the range of the angle at which the robotic lawnmower rotates relative to the guide wire is 30 degrees to 60 degrees, preferably 45 degrees.

[0017] As an exemplary embodiment of the present invention, the guide wire is a wire arranged within an area defined by boundary wires. The guide wire guides the robotic lawnmower to a predetermined location, such as a charging station and / or outside narrow passages.

[0018] As an exemplary embodiment of the present invention, the method is configured to guide a robotic lawnmower to a predetermined position, wherein at least one signal from a guide wire is a first guidance signal, and the guide wire is a first guidance signal source. The method further includes controlling the robotic lawnmower to follow the first guidance signal at a fixed distance from the first guidance signal source, detecting a second signal from a second signal source within a predetermined distance from the predetermined position using at least one sensor. The method also includes controlling the robotic lawnmower to follow the first guidance signal at the predetermined distance from the first guidance signal source, detecting a third signal from a third signal source using at least one sensor, and stopping the robotic lawnmower at the predetermined position by following the third signal.

[0019] To achieve the above objectives, the present invention also provides a method for navigating a robotic lawnmower, used to guide the robotic lawnmower to a predetermined position, wherein the robotic lawnmower includes at least one sensor, and the method includes: detecting a first guidance signal from a first guidance signal source through the at least one sensor; controlling the robotic lawnmower to follow the first guidance signal at a fixed distance from the first guidance signal source; detecting a second signal from a second signal source within a predetermined distance from the predetermined position (first guidance signal source) through the at least one sensor; controlling the robotic lawnmower to follow the first guidance signal at a predetermined distance from the first guidance signal source; detecting a third signal from a third signal source through the at least one sensor; and parking the robotic lawnmower at the predetermined position by following the third signal.

[0020] As an exemplary embodiment of the present invention, the third signal source is part of a region defined by a boundary line, or is electrically connected to the boundary line.

[0021] As an exemplary embodiment of the present invention, the first guiding signal source is a wire disposed within an area defined by a boundary line.

[0022] As an exemplary embodiment of the present invention, the third signal source is a loop of the boundary line.

[0023] As an exemplary embodiment of the present invention, a charging station is set at a predetermined location, and the boundary line is a loop set on the charging station plate of the charging station.

[0024] As an exemplary embodiment of the present invention, the robotic lawnmower is guided to a predetermined position multiple times, wherein the fixed distance changes each time, while the predetermined distance remains the same each time.

[0025] Another object of the present invention is to provide a robotic lawnmower configured to navigate by wires and to reduce the risk of creating tracks in the lawn in a simple and reliable manner.

[0026] To achieve the above objectives, the present invention provides a robotic lawnmower that includes at least one sensor and is configured to: detect at least one signal from a guide wire via the at least one sensor, align with the guide wire, rotate a portion of the guide wire by an angle, increase its distance to the guide wire by traveling a displacement distance based on a random distance value, measure the signal level of at least one signal from the guide wire via the at least one sensor, and follow the guide wire according to the measured signal level.

[0027] As an exemplary embodiment of the present invention, the robotic lawnmower is also configured to calculate the number of revolutions of the rotatable components of the robotic lawnmower and / or measure the time for travel displacement based on random distance values.

[0028] As an exemplary embodiment of the present invention, the robotic lawnmower is further configured to pass through a wire at a predetermined crossing distance, determine the direction by measuring the polarity of at least one signal of the wire by at least one sensor, and turn in the determined direction.

[0029] As an exemplary embodiment of the present invention, the robotic lawnmower includes at least two sensors configured to rotate relative to a guide wire until the two sensors detect at least one signal of opposite polarity of the guide wire.

[0030] As an exemplary embodiment of the present invention, the robotic lawnmower is further configured to follow a guide wire in a first direction until a straight portion of the guide wire is detected, and based on the detected straight portion of the guide wire, follow the guide wire in a second direction opposite to the first direction.

[0031] As an exemplary embodiment of the present invention, the robotic lawnmower is also configured to drive a reverse distance in a second direction to follow a guide, the reverse distance being derived based on a random distance value.

[0032] As an exemplary embodiment of the present invention, the robotic lawnmower is further configured to multiply a random distance value by a first factor for reverse distance and multiply the random distance value by a second factor to calculate displacement distance.

[0033] As an exemplary embodiment of the present invention, the angle of rotation of the robotic lawnmower relative to the guide wire ranges from 30 degrees to 60 degrees, preferably 45 degrees.

[0034] Another object of the present invention is to provide a robotic lawnmower to perform the above-described method.

[0035] To achieve the above objectives, the present invention provides a robotic lawnmower, the robotic lawnmower including at least one sensor and configured to detect a first guidance signal from a first guidance signal source by the at least one sensor; follow the first guidance signal at a fixed distance from the first guidance signal source; detect a second signal from a second signal source within a predetermined distance from a predetermined position by the at least one sensor; follow the first guidance signal at a predetermined distance from the first guidance signal source; detect a third signal from a third signal source by the at least one sensor; and stop the robotic lawnmower at a predetermined position by following the third signal.

[0036] As an exemplary embodiment of the present invention, the robotic lawnmower is guided to a predetermined position multiple times, wherein the fixed distance changes each time, while the predetermined distance remains the same each time.

[0037] The present invention also provides a system comprising a guide wire and the aforementioned robotic lawnmower. The guide wire is arranged within an area defined by boundary guide wires.

[0038] The present invention also provides a computer program comprising computer program code configured to be executed by one or more processors of a robotic lawnmower to cause the robotic lawnmower to perform the above-described method.

[0039] The present invention further provides a computer-readable storage medium for storing computer program code configured to be executed by one or more processors of a robotic lawnmower to cause the robotic lawnmower to perform the above-described method.

[0040] This invention provides a method for navigating a robotic lawnmower, as well as a robotic lawnmower and system, to reduce the risk of creating tracks in the lawn in a simple and reliable manner. Attached Figure Description

[0041] Exemplary embodiments will now be described with reference to the accompanying drawings.

[0042] Figure 1 This is a schematic diagram of a robotic lawnmower system.

[0043] Figure 2 This is a schematic diagram of an embodiment of a robotic lawnmower.

[0044] Figure 3 This is a schematic diagram of an embodiment of a charging station for a robotic lawnmower system.

[0045] Figure 4 This is a schematic block diagram of the control unit in a robotic lawnmower.

[0046] Figure 5 This is a schematic block diagram of a signal generator.

[0047] Figures 6A to 6S This is a schematic diagram illustrating the different stages of a robotic lawnmower system's navigation to a charging station following a guide wire.

[0048] Figure 7 This is a flowchart of a method for using a wire-guided robotic lawnmower.

[0049] Figure 8 This is a flowchart of the steps involved in using a navigation robot lawnmower. Detailed Implementation

[0050] The following description will provide a detailed description of exemplary embodiments of a robotic lawnmower that is guided by a guide wire.

[0051] Figure 1The diagram illustrates a system for executing a method of controlling a robotic lawnmower 2 to navigate to a predetermined location (e.g., charging station 11) via a wire 8. The robotic lawnmower 2, or self-propelled lawnmower, is battery-powered and requires periodic charging. During operation, the robotic lawnmower 2 moves within an area A enclosed by a boundary line 4. For clarity, the robotic lawnmower 2 is shown enlarged. The boundary line 4 can be configured in any manner to form the area A that restricts the movement of the robotic lawnmower 2. The boundary line 4 can be located above or below ground; preferably, it is located below ground and thus invisible. The boundary line 4 is a single-core ordinary copper wire. However, other options known to those skilled in the art, such as multi-strand wire types, can also be used for the boundary line 4. Figure 1 As shown, boundary line 4 forms a loop 4a within charging station 11. This loop 4a will be used to guide the robotic lawnmower 2 into charging contact with charging station 11, which will be described further below.

[0052] The robotic lawnmower system also includes a charging station 11. The charging station 11 is where the robotic lawnmower 2 is charged, and it may be equipped with a charging plate. During docking, the robotic lawnmower 2 is guided onto the charging plate. The charging plate makes the docking process more precise because the robotic lawnmower 2 will be positioned on a uniform and predictable surface during docking. To identify the location of the charging station 11, a charging station loop 10 is arranged around it. Figure 1 As shown, the boundary line loop 4a is narrower than the charging station loop 10a and passes through the charging station loop 10.

[0053] Optionally, the system of this application may also include one or more guide wires 8. Guide wires 8 are lines that the robotic lawnmower 2 can follow when returning to the charging station 11 and / or moving along hard-to-find paths. The robotic lawnmower can also be configured to follow boundary lines 4 back to the charging station 11, which can be a considerable distance depending on where the robotic lawnmower 2 begins following the boundary lines. By using guide wires 8, the robotic lawnmower 2 can be returned to the charging station 11 in a faster and less energy-intensive manner.

[0054] Boundary line 4, charging station loop 10, and one or more wires 8 are all connected to a signal generator that feeds an AC signal to each wire and loop, enabling the robotic lawnmower 2 to identify the wire or loop it is detecting within a sensing distance. Typically, the robotic lawnmower 2 can be configured to detect the magnetic fields of different signal lines.

[0055] Please see Figure 2 The image shows an exemplary embodiment of the robotic lawnmower 2. The robotic lawnmower 2 includes a control unit 22, wheels 20, at least one sensor 12, 14, and a battery 18. The control unit 22 (see...) Figure 4The system includes a processor 80 for controlling the movement of the robotic lawnmower 2. When the robotic lawnmower 2 is running, sensors 12 and 14 can sense magnetic fields generated in the boundary line 4, the charging station loop 10, and one or more wires 8. The sensed magnetic field (signal) is decoded in the control unit 22 to determine which loop or wire it originates from. The robotic lawnmower 2 also includes a charging connector 16. In this embodiment, the robotic lawnmower 2 includes two sensors 12 and 14, but in other alternative embodiments, the robotic lawnmower 2 may include more than two sensors, for example, three or four sensors.

[0056] It should be noted that the robotic lawnmower 2 has a front-to-back axis along which it moves when driven in a straight line forward or backward. In this embodiment, the robotic lawnmower 2 extends longitudinally along the front-to-back axis. Two sensors 12 and 14 are arranged offset from each other in a direction perpendicular to the front-to-back axis. In this embodiment, sensors 12 and 14 are located in the front region of the robotic lawnmower 2 and may be referred to as front sensors 12 and 14.

[0057] Please see Figure 3 As shown, the charging station 11 includes a charging station plate 24, a charging station loop 10 (also referred to as a far-field loop), and a boundary line loop 4a (also referred to as a near-field loop) arranged on the charging station plate 24. The charging station 11 also includes a signal generator 6. (As shown...) Figure 3 As shown, the charging station 11 includes a charging connector 26, which is configured to contact the charging connector 16 of the robotic lawnmower 2 when the robotic lawnmower 2 is connected to the charging station 11.

[0058] Please see Figure 4 The diagram shows the control unit 22 of the robotic lawnmower 2. As described above, the control unit 22 includes a processor 80 and a memory 82. The memory 82 includes a computer program 84 containing computer program code (i.e., instructions). When the computer program code is executed on the processor 80, it is configured to perform method steps executed by the robotic lawnmower 2. The control unit 22 also includes an interface 86 for communicating with sensors 12, 14 and one or more drive motors that control the robotic lawnmower 2.

[0059] The processor 80 may include one, two, or more central processing units (CPUs). For example, the processor 80 may include a general-purpose microprocessor, an instruction set processor, and / or an associated chipset and / or a special-purpose microprocessor, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a complex programmable logic device (CPLD). The processor 80 may also include memory for caching purposes.

[0060] Please see Figure 5 As shown, the signal generator 6 also includes a processor 60 and a memory 62. The memory 62 includes a computer program 64, which includes computer program code, i.e., instructions. The computer program code is configured to implement the method steps executed by the signal generator 6 when the code is executed on the processor 60. The signal generator 6 also includes an interface 66 for transmitting the generated AC signal to the boundary line 4, the charging station loop 10, and the wire 8.

[0061] Like processor 80, processor 60 also includes one, two, or more central processing units (CPUs). For example, processor 60 may include a general-purpose microprocessor, instruction set processor, and / or associated chipset and / or application-specific microprocessor, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a complex programmable logic device (CPLD). Processor 60 may also include memory for caching purposes.

[0062] Please see Figures 6A to 6S The embodiments will be described in more detail below.

[0063] First, a command is triggered instructing the robotic lawnmower 2 to navigate to a predetermined location, which in this embodiment is charging station 11. This command can be triggered by signal generator 6 or control unit 22. Then, the robotic lawnmower 2 begins searching for wire 8. To locate wire 8, the robotic lawnmower 2 drives through area A, and sensors 12 and 14 are used to sense the signal of wire 8. Within a certain range, such as several meters, the signal of wire 8 can be sensed by sensors 12 and 14. Once one or both of sensors 12 and 14 receive the signal of wire 8, the robotic lawnmower 2 is commanded to drive toward wire 8, for example, simply by continuing to drive in a straight line until the robotic lawnmower 2 passes wire 8.

[0064] To generate a signal for wire 8, signal generator 6 directs current through wire 8, thereby creating a polarized magnetic field around wire 8. Therefore, the polarity of the signal on one side of wire 8 is opposite to that on the other side. Once the robotic lawnmower 2 crosses wire 8, one or both of sensors 12 and 14 detect the change in polarity. By sensing this change in polarity, the robotic lawnmower 2, more precisely, the control unit 22 of the robotic lawnmower 2, is configured to determine whether the robotic lawnmower 2 has crossed wire 8.

[0065] Please see Figure 6A As shown, the robotic lawnmower 2 detects the condition of the wire 8. One of the sensors 12 and 14, sensor 12, has passed through the wire 8, while the other sensor 14 has not. Therefore, the robotic lawnmower 2 can infer that it is located directly above the wire 8.

[0066] In this embodiment, the robotic lawnmower 2 contacts the wire 8 at a certain angle, and... Figure 6A In the illustrated scenario, sensor 12 has passed through wire 8, while sensor 14 has not. By sensing the signal polarity of wire 8 using sensors 12 and 14, the robotic lawnmower 2 can directly determine that it is above wire 8. When the robotic lawnmower 2 reaches wire 8 in a direction perpendicular to wire 8, both sensors 12 and 14 will simultaneously detect the change in polarity; therefore, the robotic lawnmower 2 can infer that in this case, it is directly above wire 8.

[0067] Please see Figure 6B As shown, in response to detecting that the robotic lawnmower 2 is above the guide wire 8, the robotic lawnmower 2 is configured to be further driven (specifically, forward in a straight line) across the guide wire 8 a predetermined distance. The predetermined distance can be the length of the lawnmower or a portion thereof, or the turning radius of the robotic lawnmower 2 or a small portion thereof. After driving the predetermined distance, the two sensors 12 and 14 are located on the same side of the guide wire 8. Based on the signal polarity of the guide wire 8, the robotic lawnmower 2 determines the direction (along the guide wire 8) to the charging station 11. Next, the robotic lawnmower 2 turns left or right in the determined direction to the charging station 11. The robotic lawnmower 2 analyzes the signal polarity of the guide wire 8 when turning relative to the guide wire 8. Once one of the sensors 12 and 14 (in Figure 6B In the middle, the second sensor 14 on the left detects a change in polarity, and the robot lawnmower 2 determines that it is substantially aligned with the wire 8. In this embodiment, the wire 8 is aligned with the robot lawnmower 2 along the front and rear axis of the robot lawnmower 2.

[0068] Please see Figure 6C As shown, the robotic lawnmower 2 is aligned with the guide wire 8. Now, the robotic lawnmower 2 is facing the charging station 11 along the guide wire 8.

[0069] Next, as Figure 6D As shown, the robotic lawnmower 2 begins to traverse across the guide rail 8, with one of the sensors 12 and 14 located directly above the guide rail 8. In this embodiment, the right sensor 12 is located directly above the guide rail 8. The left sensor 14 is an external sensor of the guide ring and is located below the guide rail 8. As the robotic lawnmower 2 traverses across and moves along the guide rail 8, it searches for straight sections of the guide rail 8, particularly straight sections of a predetermined length, or lengths that are factors of a random corridor distance Rc (described in more detail below). The robotic lawnmower 2 can be configured to search for straight sections of the guide rail 8 of a certain length, wherein this length is based on different strokes (where one stroke corresponds to navigation to a predetermined position once), particularly on random values.

[0070] Please see Figure 6E As shown, the robotic lawnmower 2 travels across the guide wire 8 until it finds the straight section 8a. The straight section 8a is determined to be straight because the robotic lawnmower 2 does not need to rotate while traveling along the guide wire 8. At the straight section 8a, the guide wire 8 is arranged in a straight line. After detecting the straight section 8a, the robotic lawnmower 2 stops traveling.

[0071] After stopping at different points in time, for example, before or during the search for a straight section of guide 8, or in response to a triggered command instructing the robotic lawnmower 2 to navigate toward a predetermined location, the robotic lawnmower 2, more precisely, its control unit 22, uses a random number generator to determine a random corridor distance Rc to guide 8. The random corridor distance Rc can be used as a random distance value, or a random distance value can be calculated based on the random corridor distance Rc. The random distance value is a measure of length based on a random number. The robotic lawnmower 2 also calculates the reverse distance based on the random distance value, for example, by multiplying (or dividing) the random distance value by a factor, and / or using triangulation or more complex calculations.

[0072] Please see Figure 6F As shown, next, the robotic lawnmower 2 reverses along the straight section 8a of the guide wire 8 in the opposite direction and drives a distance in the opposite direction. The reverse distance is less than or equal to the length of the straight section 8a.

[0073] Next, the robotic lawnmower 2 rotates at a certain angle relative to the guide wire 8. For example... Figure 6G As shown, the robotic lawnmower 2 rotates towards the outside of the guide ring of the wire 8. Figure 6G In this embodiment, the robotic lawnmower 2 turns to the left. Specifically, it turns 45 degrees to the left. The turning angle of the robotic lawnmower 2 does not necessarily follow any signals.

[0074] Please see Figure 6H As shown, after turning, the robotic lawnmower 2 travels a straight distance forward. This distance is calculated by the robotic lawnmower 2 based on a random distance value, for example, by multiplying (or dividing) the random distance value by another factor, and / or using triangulation or more complex calculations. After driving the robotic lawnmower 2 to a distance at a 45-degree angle to the guide wire 8, the robotic lawnmower 2 moves towards the guide wire 8 to a random corridor distance Rc. For example, the random corridor distance Rc is the shortest distance between the robotic lawnmower 2 and the guide wire 8.

[0075] The robotic lawnmower 2 can be configured to search for a straight section 8a of a wire 8 of a certain length, wherein the length is based on a random corridor distance Rc, and / or based on the same random number used to calculate the random corridor distance Rc.

[0076] like Figure 6I As shown, the robotic lawnmower 2 then stops and rotates back an angle (45 degrees in this case) in the opposite direction to orient itself parallel to the guide wire 8. It is worth noting that when the robotic lawnmower 2 travels relative to the guide wire 8, it is not necessary to determine the signal level; instead, an odometer is required. To determine the distance traveled, particularly the displacement, the robotic lawnmower 2 can control its drive motor to operate at a given speed and calculate the travel time. Alternatively or additionally, the robotic lawnmower 2 can count the number of rotations of the rotatable components of the drive mechanism (e.g., wheels 20) to determine the travel distance.

[0077] After stopping or turning parallel to guide wire 8, the robotic lawnmower 2 determines the signal level of guide wire 8, for example, it determines the signal amplitude (e.g., by sampling the signal level). The robotic lawnmower 2 then follows guide wire 8 at that signal level. When the signal level changes while the robotic lawnmower 2 is traveling, for example due to the curvature of guide wire 8, the robotic lawnmower 2 adjusts its direction of travel accordingly. Therefore, the robotic lawnmower 2 follows the guide wire at a constant distance, which depends directly on the initial random number.

[0078] Please see Figure 6J As shown, the robotic lawnmower 2 then follows the guide wire 8 in a specific manner.

[0079] Please see Figure 6K As shown, the robotic lawnmower 2 enters the signal range of the charging station loop 10. These signals indicate to the robotic lawnmower 2 that it is approaching the charging station 11. The robotic lawnmower 2 detects the signals of the charging station loop 10 using one or two sensors 12, 14, or another sensor.

[0080] In response to the detection of a signal from charging station circuit 10, the robotic lawnmower 2 turns relative to the guide wire 8. In this embodiment, the robotic lawnmower 2 turns 90 degrees to the right (see...). Figure 6K In other words, the robotic lawnmower 2 rotates so that it can reach the wire 8 via the shortest path.

[0081] Please see Figure 6L As shown, after turning to guide wire 8, the robotic lawnmower 2 moves in a straight line toward guide wire 8 until it detects guide wire 8.

[0082] Please see Figure 6M As shown, the robotic lawnmower 2 travels in a straight line forward in the direction of the guide wire 8 until sensors 12 and 14 detect a change in the polarity of the guide wire 8. Then, the robotic lawnmower 2 continues to travel a predetermined distance in a straight line (see...). Figure 6N ).

[0083] Please see Figure 6OAs shown, the robotic lawnmower 2 can re-determine its direction toward the charging station 11 by analyzing the signal polarity of the wire 8. Then the robotic lawnmower 2 turns toward the charging station 11 until sensors 12 and 14 detect the opposite signal polarity of the wire 8.

[0084] Then, the robotic lawnmower 2 begins to travel across the guide wire 8 using either of the two sensors 12 and 14. (See also...) Figure 6P As shown, the sensor used here is the right-side sensor 12, located on the side of the robotic lawnmower 2 inside the guide ring.

[0085] Please see Figure 6Q As shown, the robotic lawnmower 2 continues to travel across the conductor 8 toward the charging station 11.

[0086] Next, please see Figure 6R As shown, the robotic lawnmower 2 detects that one or both of sensors 12 and 14 have entered the charging station loop 10. For example, entering the charging station loop 10 is determined by sensing a change in the polarity of the signal in the charging station loop 10.

[0087] In response to detecting entry into the charging station loop 10, the robotic lawnmower 2 docks on the charging station using the boundary ring 4a within the charging station plate 24. If the left sensor 14 is outside the boundary ring 4a and the right sensor 12 is inside, the robotic lawnmower 2 turns left / slightly to the left. If the left sensor 14 is inside the boundary ring 4a and the right sensor 12 is outside, the robotic lawnmower 2 turns right / slightly to the right. Otherwise, the robotic lawnmower 2 drives directly forward until the charging connectors 16, 26 engage in an operational connection, such as electrical contact. See also Figure 6S The wire 8 is positioned off-center from the centerline of the charging station 11 for precise guidance using either sensor 12 or 14. After docking, the robot lawnmower 2's battery 18 is charged.

[0088] By using random distance values ​​instead of random signal level values, the random distance can be set more accurately and reliably. The random distance value can be defined with millimeter precision. Furthermore, this setting also improves randomness. When the robotic lawnmower 2 returns to the charging station multiple times, the formation of a fixed trajectory can be effectively avoided.

[0089] Please see Figure 7The diagram illustrates a method for a robotic lawnmower 2 to navigate along a guideline. The method begins at step S100, in which the robotic lawnmower 2 processes (e.g., receives) a return signal at control unit 22, which commands the robotic lawnmower 2 to return to charging station 11. Step S100 can be triggered by detecting that the power in battery 18 is below a predetermined threshold. The predetermined threshold is set such that the robotic lawnmower 2 can safely return to charging station 11 before battery 18 is depleted, even if it happens to be the longest possible path back to charging station 11.

[0090] When the robotic lawnmower 2 has processed the command to return to the charging station 11, it starts from the mowing area A until it detects the wire 8 by one or more of the sensors 12 and 14.

[0091] In step S101, the control unit 22 detects at least one signal from a wire (e.g., wire 8) via at least one sensor, particularly a first guiding signal, wherein wire 8 is the source of the first guiding signal. Therefore, the control unit 22 determines that the wire or wire 8 is nearby.

[0092] Next, in step S102, the control unit 22 controls the robotic lawnmower 2 to align with the guide wire (e.g., guide wire 8). By aligning with the guide wire 8, the robotic lawnmower 2 is driven over the guide wire 8 and rotates such that the longitudinal extension axis of the robotic lawnmower 2 is on the same axis as the cross section of the guide wire 8 below the robotic lawnmower 2.

[0093] Optionally, in step 200, aligning with the guide wire includes crossing the guide wire 8 by the robotic lawnmower 2 at a predetermined crossing distance. This alignment includes steps S201 and S202. In step S201, the direction is determined by the polarity of at least one signal from the guide wire 8 measured by at least one sensor 12, 14. In step S202, the robotic lawnmower 2 is rotated in the determined direction. This rotation may include rotating the robotic lawnmower 2 relative to the guide wire 8 until both sensors 12, 14 detect at least one signal from the guide wire 8 with opposite polarities.

[0094] Step S102, aligning the robotic lawnmower 2 with the guide wire 8, may further include steps S203 and S204. Step S203 involves controlling the robotic lawnmower 2 to follow the guide wire 8 in a first direction until a straight portion 8a (e.g., having a predetermined length) of the guide wire 8 is detected. Step S204, in response to detecting the straight portion 8a of the guide wire 8, involves controlling the robotic lawnmower 2 to follow the guide wire 8 in a second direction opposite to the first direction. For example, the first direction is along the guide wire 8 towards the charging station 11, and the second direction is along the guide wire 8 away from the charging station.

[0095] Optionally, the method proceeds to step S103, in which the robot lawnmower 2 is controlled to rotate a certain angle relative to the straight section 8a of the guide wire 8, for example, rotating 45 degrees.

[0096] Optionally, after rotating a certain angle, according to step S104, the control unit 22 controls the robotic lawnmower 2 to travel a certain displacement distance along the direction determined in step S103, based on a random distance value, thereby increasing the distance between the robotic lawnmower 2 and the guide wire 8.

[0097] Optionally, the process proceeds to step S105, where the signal level, such as amplitude, of at least one signal from the wire 8 is measured using at least one sensor. That is, after shifting itself a certain distance, the control unit 22 samples the signal level.

[0098] Optionally, in step S106, the control unit 22 controls the robotic lawnmower 2 to follow the guide wire 8 at a constant, fixed distance. For example, based on the measured signal level, a previously set random distance from the guide wire is maintained in a simple and efficient manner. Steps S100 to S106 are repeated each time the robotic lawnmower 2 returns to the charging station 11, or generally, when it travels to a predetermined position.

[0099] In one embodiment of this application, a method is provided for guiding a robotic lawnmower 2 to a predetermined location (e.g., a charging station 11). Figure 8 As shown, the method proceeds from step S106 to step S107. Optionally, steps S102 to S105 can be omitted, or these steps can be performed.

[0100] In step S107, the robotic lawnmower 2 detects a second signal from a second signal source via at least one sensor 12, 14. This second signal is located within a predetermined distance from a predetermined position. The second signal source may be the charging station circuit 10.

[0101] Next, in step S108, the robot lawnmower 2 is controlled to follow the first guide signal at a predetermined distance from the first guide signal source. Preferably, the first guide signal source can be a wire 8.

[0102] Then, the method proceeds to step S109, in which the robotic lawnmower 2 detects a third signal from a third signal source via at least one sensor 12, 14, preferably, a loop 4a of the boundary line 4.

[0103] Finally, in step S110, the robotic lawnmower 2 is controlled to follow the third signal to dock with the robotic lawnmower 2 at a predetermined position on the charging station 11. For example, this can be achieved by electrically contacting the charging connector of the charging station 11. It is worth noting that the robotic lawnmower 2 can be guided to the predetermined position multiple times. Specifically, the robotic lawnmower 2 is configured to vary a fixed distance each time it is guided to the predetermined position, while the predetermined distance remains the same each time.

[0104] Although the invention has been described above with reference to specific embodiments, the invention is not limited to the specific forms described herein. Rather, the invention is limited only by the appended claims.

[0105] In the claims, the term "comprising / including" does not exclude the presence of other elements or steps. Furthermore, although listed separately, multiple means or elements may be implemented, for example, by a single unit or processor. Moreover, although individual features may be included in different claims, these may be advantageously combined, and inclusion in different claims does not imply that such combination of features is infeasible and / or advantageous. Furthermore, singular references do not exclude plurals. Terms such as "a," "first," "second," etc., do not exclude plurals. Reference numerals in the claims are provided as illustrative examples only and should not be construed as limiting the scope of the claims in any way.

Claims

1. A method for navigating a robotic lawnmower via a guide wire, characterized in that, The robotic lawnmower (2) includes at least one sensor (12; 14), and the method includes: Step S101: Detect at least one signal from the wire (8) using the at least one sensor (12; 14); Step S102: Align the robotic lawnmower (2) with the guide wire (8); Step S103: Control the robotic lawnmower (2) to rotate at an angle relative to the portion (8a) of the guide wire (8); Step S104: Control the robotic lawnmower (2) to travel a certain distance based on a random distance value to increase the distance between the robotic lawnmower (2) and the guide wire (8); Step S105: Measure the signal level of at least one signal from the wire (8) using at least one sensor (12; 14); and, Step S106: Control the robotic lawnmower (2) to follow the guide wire (8) based on the measured signal level; The method for aligning the robotic lawnmower (2) with the guide wire (8) in step S102 includes: Step S200: Control the robotic lawnmower (2) to pass through the guide wire (8) at a predetermined crossing distance; Step S201: Determine the direction by the polarity of at least one signal of the conductor (8) measured by the at least one sensor (12; 14); Step S202: Control the robot lawnmower (2) to rotate in the determined direction.

2. The method according to claim 1, characterized in that, The method for controlling the travel displacement distance of the robotic lawnmower (2) based on the random distance value in step S104 includes: counting the number of revolutions of the rotatable parts of the robotic lawnmower (2) and / or measuring the time.

3. The method according to claim 1, characterized in that, In step S202, the robotic lawnmower (2) includes at least two sensors (12; 14), and the robotic lawnmower (2) rotates relative to the wire (8) until the two sensors (12; 14) detect at least one signal with opposite polarity of the wire (8).

4. The method according to claim 1, characterized in that, The method for aligning the robotic lawnmower (2) with the guide wire (8) in step S102 includes: Step S203: Control the robotic lawnmower (2) to follow the guide wire (8) in the first direction until the straight section (8a) of the guide wire (8) is detected; Step S204: In response to detecting a straight portion (8a) of the guide wire (8), control the robotic lawnmower (2) to follow the guide wire (8) in a second direction opposite to the first direction.

5. The method according to claim 4, characterized in that, The method for controlling the robotic lawnmower (2) to follow the guide wire (8) along the second direction in step S204 includes: traveling a reverse distance based on the random distance value.

6. The method according to claim 5, characterized in that, The random distance value is multiplied by a first factor to calculate the reverse distance, and the random distance value is multiplied by a second factor to calculate the displacement distance.

7. The method according to claim 1, characterized in that, In step S103, the range of the angle at which the robotic lawnmower (2) rotates relative to the guide wire (8) is 30 to 60 degrees.

8. The method according to claim 1, characterized in that, The conductor (8) is a conductor arranged within the area (A) defined by the boundary line (4).

9. The method according to claim 1, characterized in that, The method is configured to guide the robotic lawnmower (2) to a predetermined position, wherein the at least one signal from the wire (8) is a first guidance signal, and the wire (8) is a source of the first guidance signal, and the method further includes: Step S106: Control the robotic lawnmower (2) to follow the first guidance signal at a fixed distance from the first guidance signal source; Step S107: Detect a second signal from a second signal source (10) within a predetermined distance from the predetermined position using the at least one sensor (12; 14); Step S108: Control the robotic lawnmower (2) to follow the first guidance signal at a predetermined distance from the first guidance signal source; Step S109: Detect the third signal from the third signal source (4a) using the at least one sensor (12; 14), and, Step S110: Control the robotic lawnmower (2) to follow the third signal to park the robotic lawnmower (2) at the predetermined position.

10. A method for guiding a robotic lawnmower to a predetermined position, characterized in that, The robotic lawnmower (2) includes at least one sensor (12; 14), and the method includes: Step S101: Detect a first guidance signal from the first guidance signal source using the at least one sensor (12; 14); Step S106: Control the robotic lawnmower (2) to follow the first guidance signal at a fixed distance from the first guidance signal source; Step S107: Detect a second signal from a second signal source (10) within a predetermined distance from the predetermined position using the at least one sensor (12; 14); Step S108: Control the robotic lawnmower (2) to follow the first guidance signal at a predetermined distance from the first guidance signal source; Step S109: Detect a third signal from the third signal source (4a) using the at least one sensor (12; 14); and Step S110: Control the robotic lawnmower (2) to follow the third signal to park the robotic lawnmower (2) at the predetermined position; The distance between the robotic lawnmower (2) and the wire is set by using a random distance value instead of a random signal level value. The random distance value is defined with millimeter precision, and the random distance value causes the fixed distance to change each time the robotic lawnmower (2) is guided to the predetermined position multiple times. The robotic lawnmower (2) is also configured to pass through the wire at a predetermined crossing distance, determine the direction by the polarity of the at least one signal of the wire measured by the at least one sensor (12; 14), and turn in the determined direction.

11. The method according to claim 10, characterized in that: The third signal source (4a) is part of the region (A) defined by the boundary line (4), or is electrically connected to the boundary line (4).

12. The method according to claim 11, characterized in that: The first guiding signal source is a conductor (8) arranged in the area (A) defined by the boundary line (4).

13. The method according to claim 11, characterized in that: The third signal source (4a) is the loop of the boundary line (4).

14. The method according to claim 13, characterized in that: A charging station (11) is set at the predetermined location, and the loop of the boundary line (4) is set at the charging station plate (24) in the charging station (11).

15. A robotic lawnmower, characterized in that, Includes at least one sensor (12; 14), and is configured as follows: At least one signal from the wire (8) is detected by the at least one sensor (12; 14). Aligned with the wire (8), Rotate by an angle relative to the portion of the conductor (8), The distance to the conductor (8) is increased by traveling a displacement distance based on a random distance value. The signal level of the at least one signal from the wire (8) is measured by the at least one sensor (12; 14), and Follow the wire (8) according to the measured signal level; The robotic lawnmower (2) is also configured to pass through the wire (8) at a predetermined crossing distance, determine the direction by the polarity of the at least one signal of the wire (8) measured by the at least one sensor (12; 14), and turn in the determined direction.

16. The robotic lawnmower according to claim 15, characterized in that, The robotic lawnmower (2) is also configured to calculate the number of revolutions of the rotatable parts of the robotic lawnmower (2) and / or measure the time of travel displacement based on the random distance value.

17. The robotic lawnmower according to claim 16, characterized in that, The robotic lawnmower (2) includes at least two sensors (12; 14) and is also configured to rotate relative to the conductor (8) until the two sensors (12; 14) detect at least one signal of opposite polarity of the conductor (8).

18. The robotic lawnmower according to claim 15, characterized in that, The robotic lawnmower (2) is configured to follow the guide wire (8) in a first direction until a straight portion (8a) of the guide wire (8) is detected, and in response to the detection of the straight portion (8a) of the guide wire (8), follow the guide wire (8) in a second direction opposite to the first direction.

19. The robotic lawnmower according to claim 18, characterized in that, The robotic lawnmower (2) is also configured to travel a reverse distance in a second direction to follow the guide wire (8), the reverse distance being derived based on the random distance value.

20. The robotic lawnmower according to claim 19, characterized in that, The robotic lawnmower (2) is further configured to multiply the random distance value by a first factor to calculate the reverse distance, and to multiply the random distance value by a second factor to calculate the displacement distance.

21. The robotic lawnmower according to claim 15, characterized in that, The robotic lawnmower (2) rotates at an angle ranging from 30 degrees to 60 degrees relative to the guide wire (8).

22. The robotic lawnmower according to claim 15, characterized in that, The robotic lawnmower (2) is configured to perform the method as described in any one of claims 1-14.

23. A robotic lawnmower, characterized in that, Includes at least one sensor (12; 14), and is configured as follows: The first guidance signal from the first guidance signal source is detected by the at least one sensor (12; 14). Follow the first guide signal at a fixed distance from the first guide signal source. The second signal from the second signal source (10) is detected within a predetermined distance from the predetermined position by the at least one sensor (12; 14). Follow the first guide signal at a predetermined distance from the first guide signal source. The third signal from the third signal source (4a) is detected by the at least one sensor (12; 14), and The robot lawnmower (2) is parked at a predetermined position following the third signal; The distance between the robotic lawnmower (2) and the wire is set by using a random distance value instead of a random signal level value. The random distance value is defined with millimeter precision, and the random distance value causes the fixed distance to change each time the robotic lawnmower (2) is guided to the predetermined position multiple times. The robotic lawnmower (2) is also configured to pass through the wire at a predetermined crossing distance, determine the direction by the polarity of the at least one signal of the wire measured by the at least one sensor (12; 14), and turn in the determined direction.

24. A robotic lawnmower system, characterized in that: Includes a wire (8) and a robotic lawnmower (2) according to any one of claims 15-23, wherein the wire (8) is a wire arranged within an area (A) defined by a boundary line (4).

25. A computer program product, characterized in that: The computer program product includes computer program code configured to be executed by one or more processors (80) of the robotic lawnmower (2) to cause the robotic lawnmower (2) to perform the method as described in any one of claims 1-14.

26. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store computer program code configured to be executed by one or more processors (80) of the robotic lawnmower (2) to cause the robotic lawnmower (2) to perform the method as described in any one of claims 1-14.

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