AUTONOMOUS MOTION SYSTEM

Abstract

An autonomous motion system can include a work robot configured to perform a work operation while moving autonomously within a work area, a charging station configured to charge the work robot, a boundary wire defining the work area, and a station wire located at the charging station and electrically connected to the boundary wire. The work robot can include a magnetic detection unit configured to detect a magnetic field generated by the boundary wire and a magnetic field generated by the station wire, and a control unit configured to detect the station wire based on a detection result from the magnetic detection unit.The charging station can have a charging port configured to be electrically connected to the working robot and a signal generator configured to supply an identical electrical signal to the boundary wire and the station wire.

Description

TECHNICAL FIELD

[0001] The disclosure herein relates to a system for autonomous movement (hereinafter autonomous movement system). STATE OF THE ART

[0002] An autonomous movement system is disclosed in JP 2017 - 182 635 A. The autonomous movement system comprises a work robot configured to perform a work operation while moving autonomously within a work area, a charging station configured to charge the work robot, a boundary wire defining the work area and generating a magnetic field when a current flows in the boundary wire, and a station wire arranged at (near) the charging station and generating a magnetic field when current flows in the station wire.The work robot includes a work unit configured to perform the work operation, a work motor configured to drive the work unit, a movement unit configured to move the work robot, a movement motor configured to drive the movement unit, a battery configured to be charged at the charging station and to supply power to the work motor and the movement motor, a magnetic detection unit configured to detect the magnetic field generated by the boundary wire and the magnetic field generated by the station wire, and a control unit configured to control the work motor and the movement motor and to detect the station wire based on a detection result by the magnetic detection unit.The charging station includes a charging port configured to be electrically connected to the work robot, a first signal generator configured to supply a first electrical signal to the boundary wire, and a second signal generator configured to supply a second electrical signal to the station wire. SHORT SUMMARY

[0003] The autonomous movement system described above requires the second signal generator to be configured to supply the second electrical signal to the station wire in order to detect the station wire. This complicates the configuration of the charging station. The disclosure herein provides a technology that enables the detection of a station wire using a simple charging station configuration.

[0004] The above-mentioned object is achieved by an autonomous movement system according to claim 1.

[0005] An autonomous movement system disclosed herein may include a work robot configured to perform a work operation while moving autonomously within a work area, a charging station configured to charge the work robot, a boundary wire defining the work area, at which the boundary wire generates a magnetic field when a current flows in the boundary wire, and a station wire disposed at (at) the charging station and electrically connected to the boundary wire, at which the station wire generates a magnetic field when a current flows in the station wire.The work robot may include a work unit configured to perform the work operation, a work motor configured to drive the work unit, a movement unit configured to move the work robot, a movement motor configured to drive the movement unit, a battery configured to be charged at the charging station and to supply power to the work motor and the movement motor, a magnetic detection unit configured to detect the magnetic field generated by the boundary wire and the magnetic field generated by the station wire, and a control unit configured to control the work motor and the movement motor and detect the station wire based on a detection result of the magnetic detection unit.The charging station may include a charging port configured to be electrically connected to the working robot and a signal generator configured to supply an identical electrical signal to the boundary wire and the station wire.

[0006] According to the configuration described above, the single signal generator supplies the identical electrical signal to the boundary wire and the station wire. This enables detection of the station wire using the simple charging station configuration. SHORT DESCRIPTION OF THE DRAWING Fig. 1 schematically shows an autonomous movement system 10 according to an embodiment. Fig. 2 shows a side view of a working robot 12 and a charging station 14 according to the embodiment. Fig. 3 shows a rear view of the working robot 12 according to the embodiment. Fig. 4 shows a plan view of the working robot 12 according to the embodiment. Fig. 5 shows an electrical block diagram of the work robot 12 according to the embodiment. Fig. 6 schematically shows a part of the autonomous movement system 10 near the charging station 14 according to the embodiment. Fig. 7 is a drawing showing current waveforms CW1 of a first electrical signal and current waveforms CW2 of a second electrical signal. Fig. 8 shows a waveform for magnetic field strengths inside and outside a working area WA and a waveform for magnetic field strengths inside and outside a guide area GA. Fig. 9 shows a waveform for magnetic field strengths inside and outside an area surrounded by a station wire 20 according to the embodiment. Fig. 10 shows a flow diagram of an autonomous movement process. Fig. 11 shows a flowchart of a separation process according to the embodiment. Fig. 12 shows a flowchart of a return process according to the embodiment. Fig. 13 shows a positional relationship between the work robot 12 according to the embodiment, which moves in a return direction D3, and a guide wire 18 or a first boundary wire portion 16a. Fig. 14 shows a positional relationship between the work robot 12 according to the embodiment, which moves in a return direction D4, and a boundary wire 16. Fig. 15 shows a flowchart of a docking process according to the embodiment. Fig. 16 shows how the working robot 12 moves during the docking process according to the embodiment. Fig. 17 shows a flowchart of an avoidance process according to the embodiment. DESCRIPTION

[0007] Representative, non-limiting examples of the present disclosure are described in detail below with reference to the accompanying drawings. This detailed description is merely intended to teach a person skilled in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the present disclosure. Furthermore, each of the additional features and teachings disclosed below may be used separately or in conjunction with other features and teachings to provide improved autonomous motion systems and methods of making and using the same.

[0008] Furthermore, combinations of features and steps described in detail below may not be necessary to practice the present disclosure in its broadest sense, and are instead taught merely to specifically describe preferred examples of the present disclosure. Furthermore, various features of the representative examples described above and below, and of the independent and dependent claims, may be combined in ways not specifically and explicitly recited to provide additional useful embodiments of the present teachings.

[0009] All features disclosed in the description and / or claims are intended to be considered separate and independent of each other for the purpose of original disclosure and also for the purpose of limiting the claimed invention, regardless of the combination of features in the embodiments and / or the claims. Furthermore, all ranges or groupings of units are intended to disclose any possible intermediate values ​​or subsets of units for the purpose of original disclosure and also for the purpose of limiting the claimed invention.

[0010] In one or more embodiments, the station wire may include a magnetic field enhancement structure configured to generate, when a current flows in the station wire, the magnetic field having a higher strength (intensity) than the strength (intensity) of the magnetic field generated by the boundary wire when a current flows in the boundary wire.

[0011] In the configuration described above, the strength of the magnetic field generated by the station wire is higher than the strength of the magnetic field generated by the boundary wire. This simplifies the detection of the station wire.

[0012] In one or more embodiments, the control unit may be configured to detect the station wire based on at least the strength of the magnetic field generated by the station wire when a current flows in the station wire.

[0013] The configuration described above allows the station wire to be detected with the simple configuration that uses the magnetic field strength.

[0014] In one or more embodiments, the station wire may be electrically connected in series with the boundary wire.

[0015] The configuration described above allows the identical electrical signal to be supplied to the boundary wire and the station wire using the simple configuration.

[0016] In one or more embodiments, the control unit may be configured to store the strength of the magnetic field of the station wire when the work robot is at the charging station and to detect the station wire based on the stored strength of the magnetic field and the strength of the magnetic field of the station wire detected by the magnetic detection unit.

[0017] The configuration described above enables more accurate detection of the station wire compared to configurations in which the control unit does not store the strength of the magnetic field of the station wire when the work robot is at the charging station, such as a configuration in which the strength of the magnetic field is stored in advance during the manufacturing of the work robot, a configuration in which the strength of the magnetic field is set by a user, etc.

[0018] In one or more embodiments, the control unit may be configured to perform a separation process for separating the work robot electrically connected to the charging port from the charging station, and to obtain the strength of the magnetic field of the station wire after the work robot is separated from the charging port during the separation process.

[0019] In a configuration where the control unit receives the strength of the magnetic field of the station wire before the work robot is disconnected from the charging port, the control unit must receive the strength of the magnetic field of the station wire while determining whether the work robot has been disconnected from the charging station. The configuration described above allows the control unit to determine the separation of the work robot from the charging port and separately obtain the strength of the magnetic field of the station wire.

[0020] In one or more embodiments, the separation process may include a turning process for turning the work robot after it has been separated from the charging port. The control unit may be configured to maintain the strength of the magnetic field of the station wire during the turning process.

[0021] In the configuration described above, where the work robot rotates (turns), the distance between the work robot and the charging station is less likely to change compared to a configuration where the work robot moves away from the charging station in a straight line. Since the control unit receives the strength of the magnetic field of the station wire during the rotation process, the change (fluctuation) in the magnetic field strength is small compared to a configuration where the control unit receives the strength of the magnetic field of the station wire while the work robot moves away from the charging station in a straight line.

[0022] In one or more embodiments, the magnetic sensing unit may include a plurality of magnetic sensors configured to sense the magnetic field generated by the boundary wire and the magnetic field generated by the station wire. The control unit may be configured to receive the strengths of the magnetic field of the station wire sensed by the plurality of magnetic sensors during the rotation process.

[0023] The configuration described above allows the station wire to be detected even if one of the majority of magnetic sensors is defective (fails).

[0024] In one or more embodiments, the control unit may be configured to store a peak strength (maximum strength, peak intensity) of the magnetic field of the station wire.

[0025] The configuration described above enables accurate detection of the station wire using the peak strength of the station wire's magnetic field.

[0026] In one or more embodiments, the control unit may be configured to set a threshold equal to or greater than 80% of the stored peak strength and detect the station wire based on the set threshold and the strength of the magnetic field of the station wire detected by the magnetic detection unit.

[0027] The strength of the magnetic field detected by the magnetic detection unit decreases as the distance between the work robot and the station wire increases. Since the threshold is set as a predetermined proportion of the peak magnetic field strength, the configuration described above enables detection of the station wire even when the work robot is far away from the station wire.

[0028] In one or more embodiments, the station wire may include a first loop region (loop region) configured to increase an absolute value of a positive value of the strength of the magnetic field of the station wire, and a second loop region (loop region) configured to increase an absolute value of a negative value of the strength of the magnetic field of the station wire. The control unit may be configured to control the movement motor based on the strength of the magnetic field generated by the first loop region to move the work robot along the first loop region.

[0029] In general, the station wire is detected more accurately in a configuration where the control unit detects the station wire based on the positive value of the magnetic field strength than in a configuration where the control unit detects the station wire based on the negative value of the magnetic field strength. In the configuration described above, the strength of the magnetic field generated by the first loop area is utilized, and thus the work robot can be moved accurately along the first loop area.

[0030] In one or more embodiments, the control unit may be configured to perform a docking process for electrically connecting the work robot to the charging port when the control unit detects the station wire while the work robot is returning to the charging station.

[0031] If the docking process is performed according to methods different from the method for detecting the station wire, for example, in response to a GPS detecting the position of the work robot, the work robot may collide with the charging station before the docking process is performed because the detected position of the work robot may be different from the current position of the work robot. With the configuration described above, the docking process is performed in response to the detection of the station wire, so that the collision of the work robot with the charging station can be prevented.

[0032] In one or more embodiments, the control unit may be configured to execute a movement direction changing process to change a movement direction of the work robot when the control unit detects the station wire while the work robot is performing the work operation.

[0033] The configuration described above prevents the work robot from colliding with the charging station.

[0034] (Embodiment) As in Fig. 1, an autonomous movement system 10 includes a work robot 12, a charging station 14, a boundary wire 16, a guide wire 18, and a station wire 20. The work robot 12 is, for example, a mowing device (robot lawnmower). The work robot 12 is placed on the ground when in use. The work robot 12 mows a lawn on the ground, moving autonomously within a work area WA while being surrounded by the boundary wire 16. Hereinafter, a longitudinal direction of the work robot 12 is referred to as a front-to-back direction, a width direction of the work robot 12 is referred to as a right-to-left direction, and a direction perpendicular to the front-to-back direction and the right-to-left direction is referred to as an up-to-down direction.

[0035] As in Fig. 2, the working robot 12 comprises a housing 24, a power unit 26, a working motor 28, a working unit 30, a right movement motor 32 (see Fig. 3), a left movement motor 34 (see Fig. 3), a movement unit 36, an actuation unit 38 (see Fig. 3), a display unit 39a (see Fig. 3), an information unit 39b (see Fig. 3), a magnetic detection unit 40 (see Fig. 4) and a control unit 42 (see Fig. 5).

[0036] The power unit 26 is accommodated in the housing 24. The power unit 26 has a battery 46 and a charging interface 48. The battery 46 is a secondary battery comprising a lithium-ion battery. The battery 46 is not removable from the housing 24. The charging interface 48 is located at the front end of the housing 24. The charging interface 48 is electrically connected to the battery 46. The work robot 12 is configured to be charged at the charging station 14 (see Fig. 1) via the charging interface 48. When the work robot 12 is docked at the charging station 14, the battery 46 can be charged with power supplied through the charging station 14 and the charging interface 48 from an external power source 78.

[0037] The working motor 28 is mounted on the housing 24. The working motor 28 is a brushless motor, for example. The working motor 28 operates using power from the battery 46.

[0038] The working unit 30 has a substantially disc-shaped cutting blade (blade) 30a. The cutting blade 30a is fixed to the output shaft of the working motor 28. The output shaft tilts relative to the up-down direction. The cutting blade 30a is rotated by the working motor 28, thereby mowing the grass on the ground.

[0039] As in Fig. 3, the right motion motor 32 and the left motion motor 34 are supported by the housing 24. The right motion motor 32 and the left motion motor 34 are, for example, brushless motors. The right motion motor 32 and the left motion motor 34 operate with the power from the battery 46 (see Fig. 2).

[0040] The movement unit 36 ​​includes a right front auxiliary wheel 52, a left front auxiliary wheel 54, a right rear drive wheel 56, and a left rear drive wheel 58. The right front auxiliary wheel 52 and the left front auxiliary wheel 54 are rotatably mounted on the housing 24. The right rear drive wheel 56 is fixed to the output shaft of the right movement motor 32. The left rear drive wheel 58 is fixed to the output shaft of the left movement motor 34. The output shafts of the right movement motor 32 and the left movement motor 34 extend in the right-left direction. The right rear drive wheel 56 is rotated by the right movement motor 32, and the left rear drive wheel 58 is rotated by the left movement motor 34, thereby moving the work robot 12 forward and backward as well as rotating the work robot 12.

[0041] The actuating unit 38 is located on the outer surface of the housing 24. The actuating unit 38 has actuatable (manipulable) switches. A user actuates the actuating unit 38, e.g., to switch the working robot 12 between an on state and an off state, to set a working condition of the working robot 12, etc.

[0042] The display unit 39a is, for example, a display. The display unit 39a displays various information. The operating unit 38 and the display unit 39a can be integrated as a touchscreen.

[0043] The information unit 39b is, for example, a buzzer configured to emit a sound. Alternatively, the information unit 39b may be a light device configured to emit light. The information unit 39b emits a sound when, for example, an abnormality occurs in the work robot 12.

[0044] As in Fig. As shown in Figure 4, the magnetic detection unit 40 is supported by the housing 24. The magnetic detection unit 40 includes a plurality of magnetic sensors 60 (four magnetic sensors 60 in this embodiment). The magnetic sensors 60 are, for example, search coils, Hall sensors, or the like. Each of the magnetic sensors 60 detects a magnetic field strength (magnetic field intensity) in the up-down direction.

[0045] The plurality of magnetic sensors 60 includes a right front magnetic sensor 60a, a left front magnetic sensor 60b, a center front magnetic sensor 60c, and a rear magnetic sensor 60d. The right front magnetic sensor 60a, the left front magnetic sensor 60b, and the center front magnetic sensor 60c are located in front of the center of the housing 24 in the front-rear direction. The right front magnetic sensor 60a is located in a right front area of ​​the housing 24. The left front magnetic sensor 60b is located in a left front area of ​​the housing 24. In the right-left direction, a distance from the right front magnetic sensor 60a to the center line CL is substantially equal to a distance from the left front magnetic sensor 60b to the center line CL. The center line CL extends in the front-rear direction and is located in the center of the housing 24 in the right-left direction.The center front magnetic sensor 60c and the rear magnetic sensor 60d are located near the center line CL. The center front magnetic sensor 60c is located in a front area of ​​the housing 24. The rear magnetic sensor 60d is located behind the center of the housing 24 in the front-to-rear direction. The rear magnetic sensor 60d is located in a rear area of ​​the housing 24.

[0046] As in Fig. As shown in Figure 5, the control unit 42 is electrically connected to the power unit 26, the work motor 28, the right movement motor 32, the left movement motor 34, the operation unit 38, the display unit 39a, the information unit 39b, and the magnetic detection unit 40. The control unit 42 includes a microcomputer (not shown) and a memory (not shown). The control unit 42 controls the rotation direction and speed of the right movement motor 32 independently of the rotation direction and speed of the left movement motor 34. For example, when the control unit 42 controls the right movement motor 32 and the left movement motor 34 to rotate in the forward direction at the same speed, the work robot 12 moves forward.When the control unit 42 controls the right movement motor 32 and the left movement motor 34 to rotate in the reverse direction at the same speed, the work robot 12 moves backward. When the control unit 42 controls the right movement motor 32 and the left movement motor 34 to rotate in the forward direction and the left movement motor 34 to rotate in the reverse direction, the work robot 12 turns in place. When the control unit 42 controls the right movement motor 32 and the left movement motor 34 to rotate in the forward direction (or in the reverse direction) at different speeds, the work robot 12 turns (bends) while moving forward (or backward). The control unit 42 autonomously controls the work robot 12 according to various programs stored in the memory.For example, by the control unit 42 receiving signals from the actuation unit 38 and the magnetic detection unit 40 and controlling the working motor 28, the right movement motor 32, and the left movement motor 34, respectively, the working robot 12 can mow the lawn while moving autonomously.

[0047] As in Fig. 6, a part of the charging station 14 is located within the working area WA, and another part thereof is located outside the working area WA. The charging station 14 has a base (pad, mat) 70, a post 72, a charging port 74, and a signal generator 76. The base 70 is placed on the ground. The post 72 is located on the base 70. The post 72 has a substantially cuboid shape. The post 72 is electrically connected to the external power source 78. The charging port 74 protrudes from the post 72 in a direction away from the boundary wire 16. The charging port 74 is substantially perpendicular to the post 72. The charging port 74 is located within the working area WA. As shown in Fig. As shown in Figure 2, the charging port 74 is configured to dock with the charging interface 48 of the work robot 12. When the charging port 74 docks with the charging interface 48, the charging station 14 is electrically connected to the work robot 12. Here, "the work robot 12 is (is located) at the charging station 14" means that at least a part of the work robot 12 overlaps with the charging station 14 (the base 70, the stand 72, the charging port 74, the signal generator 76) in the up-down direction.

[0048] As in Fig. 6, the signal generator 76 is housed in the stand 72. The signal generator 76 is configured to supply a first electrical signal to the boundary wire 16 and the station wire 20. Furthermore, the signal generator 76 is also configured to supply a second electrical signal to the boundary wire 16 and the guide wire 18. The second electrical signal is different from the first electrical signal. As shown in Fig. As shown in Figure 7, a current waveform CW1 of the first electrical signal is different from a current waveform CW2 of the second electrical signal. For example, the phase of the current waveform CW1 of the first electrical signal is different from the phase of the current waveform CW2 of the second electrical signal. The first electrical signal and the second electrical signal are alternately supplied by the signal generator 76, for example. The first electrical signal and the second electrical signal are supplied by the signal generator 76, for example, at predetermined intervals.

[0049] As in Fig. 1, the boundary wire 16 defines the working area WA. For example, the boundary wire 16 is buried in the ground near the ground surface. The boundary wire 16 is electrically connected to the signal generator 76 (see Fig. 6) of the charging station 14 via the station wire 20. When a current flows in the boundary wire 16, a magnetic field surrounding the boundary wire 16 is generated according to Ampere's law. The direction of the magnetic field within the working area WA differs from the direction of the magnetic field outside the working area WA. As shown in Fig. As shown in Figure 8, the strength of the magnetic field in the up-down direction at / immediately above the boundary wire 16 is zero, indicates a positive value within the working area WA, and indicates a negative value outside the working area WA. The strength of the magnetic field depends on the distance from the boundary wire 16. The control unit 42 receives the strength of the magnetic field from the magnetic detection unit 40 and determines whether the working robot 12 is within the working area WA.

[0050] As in Fig. 1, for example, the guide wire 18 is buried in the ground near the ground surface. The material and diameter of the guide wire 18 are the same as those of the boundary wire 16. The guide wire 18 is electrically connected to a first location 17 of the boundary wire 16. The first location 17 may be positioned anywhere between one end and the other end of the boundary wire 16. Hereinafter, a portion of the boundary wire 16 between the one end and the first location 17 may be referred to as a first boundary wire portion 16a, and the other portion of the boundary wire 16 between the first location 17 and the other end may be referred to as a second boundary wire portion 16b. The guide wire 18 is also electrically connected to the signal generator 76 (see Fig. 6) of the charging station 14. The guide wire 18 and the first boundary wire region 16a define a guidance area GA. When a current flows in the guide wire 18 and the first boundary wire region 16a, a magnetic field surrounding the guide wire 18 and the first boundary wire region 16a is generated according to Ampere's law. In this embodiment, an electrical signal supplied to the boundary wire 16 (the first boundary wire region 16a and the second boundary wire region 16b) is different from an electrical signal supplied to the guide wire 18 and the first boundary wire region 16a. The control unit 42 receives the strength of the magnetic field from the magnetic detection unit 40 and determines whether the work robot 12 is within the guidance area GA.

[0051] As in Fig. 6, the station wire 20 is located at the base 70 of the charging station 14. The station wire 20 is electrically connected in series with the boundary wire 16. The station wire 20 is also electrically connected with the signal generator 76 (see Fig. 6). The material and diameter of the station wire 20 are the same as those of the boundary wire 16. The station wire 20 includes a magnetic field enhancement structure 80. The magnetic field enhancement structure 80 generates a magnetic field having a higher strength (intensity) than both the absolute value of the peak strength of the magnetic field generated by the boundary wire 16 and the absolute value of the peak strength of the magnetic field generated by the guide wire 18.

[0052] The magnetic field enhancement structure 80 includes a first loop region 82 and a second loop region 84, each of which has a loop shape. The first loop region 82 and the second loop region 84 are adjacent to each other. The charging port 74 of the charging station 14 is located on the boundary between the first loop region 82 and the second loop region 84. The first loop region 82 and the second loop region 84 are formed by winding the single station wire 20 more than once (e.g., twice). The first number of turns of the station wire 20 in the first loop region 82 is the same as a second number of turns of the station wire 20 in the second loop region 84.In the station wire 20, current flows in a counterclockwise direction D1 in the first loop region 82 and flows in a clockwise direction D2 in the second loop region 84. As shown in FIG. Fig. As shown in Fig. 9, the strength of the magnetic field in the up-down direction near the base 70 is zero in the vicinity of the boundary between the first loop region 82 and the second loop region 84, indicates a positive value within the first loop region 82, and indicates a negative value within the second loop region 84. The absolute value of the peak strength of a magnetic field generated by the first loop region 82 is substantially the same as the absolute value of the peak strength of a magnetic field generated by the second loop region 84. The absolute value of the peak strength of the magnetic field generated by the first loop region 82 is greater than both the absolute value of the peak strength of the magnetic field of the perimeter wire 16 within the working area WA and the absolute value of the peak strength of the magnetic field of the guide wire 18 within the guide area GA.For example, the absolute value of the peak strength of the magnetic field generated by the first loop region 82 increases proportionally to the first number of turns of the station wire 20. The absolute value of the peak strength of the magnetic field generated by the second loop region 84 is greater than both the absolute value of the peak strength of the magnetic field generated by the boundary wire 16 outside the working area WA and the absolute value of the peak strength of the magnetic field generated by the guide wire 18 outside the guide area GA. For example, the absolute value of the peak strength of the magnetic field generated by the second loop region 84 increases proportionally to the second number of turns of the station wire 20.The control unit 42 receives one or more strengths of the magnetic fields from the magnetic detection unit 40 to determine whether the work robot 12 is within the first loop area 82 and / or within the second loop area 84, and to detect that the work robot 12 crossed (traversed / ran over) the station wire 20.

[0053] (Autonomous movement process) The control unit 42 executes an autonomous movement process which is Fig. 10. The autonomous movement process is performed to detach the work robot 12 from the charging station 14, cause the work robot 12 to perform a mowing operation within the work area WA, return the work robot 12 to the charging station 14, and dock the work robot 12 to the charging station 14.

[0054] Before S2 from Fig. 10, the charging interface 48 of the working robot 12 is docked to the charging port 74 of the charging station 14, that is, the working robot 12 is electrically connected to the charging station 14. In S2, the control unit 42 executes a separation process.

[0055] In S102 of the separation process, which is Fig. 11, the control unit 42 controls the right movement motor 32 and the left movement motor 34 to rotate in the reverse direction at the same speed so that the charging interface 48 of the working robot 12 moves away from the charging port 74.

[0056] In S104, the control unit 42 determines whether the charging interface 48 has been uncoupled (electrically disconnected) from the charging port 74. If the control unit 42 determines that the charging interface 48 has been uncoupled from the charging port 74 (YES in S104), the process proceeds to S106.

[0057] In S106, the control unit 42 controls the magnetic detection unit 40. In this embodiment, the control unit 42 controls the right front magnetic sensor 60a, the left front magnetic sensor 60b, and the center front magnetic sensor 60c, and starts obtaining magnetic field strengths of the first loop area 82 detected by the magnetic sensors 60a, 60b, 60c.

[0058] In S108, the control unit 42 controls the right motion motor 32 and the left motion motor 34 to rotate the work robot 12 in place. For example, the control unit 42 controls the right motion motor 32 and the left motion motor 34 such that the right motion motor 32 rotates in the forward direction (or reverse direction) and the left motion motor 34 rotates in the reverse direction (or forward direction). When the work robot 12 has rotated 180 degrees in place, the control unit 42 stops the right motion motor 32 and the left motion motor 34.

[0059] In S112, the control unit 42 selects a magnetic sensor 60 from the three magnetic sensors 60a, 60b, 60c based on the waveforms of the magnetic field strengths of the first loop region 82 detected by the magnetic sensors 60a, 60b, 60c. The control unit 42 obtains the peak strength of the magnetic field of the first loop region 82 from the waveform of the magnetic field strength of the first loop region 82 detected by the selected magnetic sensor 60. The control unit 42 stores the obtained peak strength. In a modification, the control unit 42 may select one magnetic sensor 60 from the three magnetic sensors 60a, 60b, 60c based on waveforms of the magnetic field strengths of the second loop region 84 detected by the magnetic sensors 60a, 60b, 60c, and store the peak strengths of the magnetic field of the second loop region 84.

[0060] In S114, the control unit 42 sets a threshold based on the stored peak intensity. The threshold is equal to or greater than 80% of the stored peak intensity. Furthermore, the threshold is equal to or less than 100% of the stored peak intensity. The control unit 42 saves the set threshold.

[0061] In S116, the control unit 42 controls the right movement motor 32 and the left movement motor 34 to rotate in the forward direction, so that the work robot 12 moves away from the charging station 14. The rotational speed of the right movement motor 32 may be the same as or different from that of the left movement motor 34.

[0062] In S118, the control unit 42 determines whether the strengths of the magnetic field of the first loop area 82 detected by the magnetic sensors 60a, 60b, 60c, 60d are equal to or less than a reference value. The fact that the strengths of the magnetic field of the first loop area 82 are equal to or less than the reference value means that the work robot 12 is a predetermined distance (e.g., one meter) away from the charging station 14. If the control unit 42 determines that the detected strengths of the magnetic field of the first loop area 82 are equal to or less than the reference value (YES in S118), the process proceeds to S4 of the autonomous movement process described in Fig. 10 is shown.

[0063] In S4 of Fig. 10, the control unit 42 executes a mowing process. Specifically, the control unit 42 controls the working motor 28, the right movement motor 32, and the left movement motor 34. Thus, the working robot 12 moves within the working area WA while the cutting blade 30a rotates, thereby mowing the lawn within the working area WA.

[0064] In S6, the control unit 42 determines whether a return condition is met. The control unit 42 determines that the return condition is met when, for example, the remaining power amount (charge level) of the battery 46 reaches a predetermined amount or less. Alternatively, the control unit 42 may determine that the return condition is met when the current time is past a time set by the user, or when an abnormality occurs in at least one of the working motor 28, the right movement motor 32, and the left movement motor 34. If the control unit 42 determines that the return condition is met (YES in S6), the process proceeds to a return process in S8.

[0065] In the return process that Fig. As shown in Figure 12, the control unit 42 continues to control the working motor 28, the right movement motor 32, and the left movement motor 34, that is, the working robot 12 moves within the working area WA while the cutting blade 30a rotates. Thus, the lawn within the working area WA is also mowed during the return process.

[0066] In S202, the control unit 42 determines whether the rear magnetic sensor 60d has crossed the guide wire 18 or the first boundary wire region 16a within a predetermined period of time. The control unit 42 determines that the rear magnetic sensor 60d has crossed the guide wire 18 or the first boundary wire region 16a when a strength of the magnetic field of the guide wire 18 or the first boundary wire region 16a detected by the rear magnetic sensor 60d changes from a positive value to a negative value. If the control unit 42 determines that the rear magnetic sensor 60d has crossed the guide wire 18 or the first boundary wire region 16a within a predetermined period of time (YES in S202), the process proceeds to S204.When the control unit 42 determines that the rear magnetic sensor 60d has not crossed the guide wire 18 or the first boundary wire area 16a within the predetermined period of time (NO in S202), the process proceeds to S206.

[0067] In S204, the control unit 42 controls the right movement motor 32 and the left movement motor 34 to move the work robot 12 in a return direction D3 along the guide wire 18 and the first boundary wire area 16a. As shown in Fig. 1, the return direction D3 is counterclockwise. The return direction D3 is the same as the direction of the current flowing in the guide wire 18 and the first boundary wire portion 16a.

[0068] As in Fig. As shown in Figure 13, while the work robot 12 moves in the return direction D3 along the guide wire 18 and the first boundary wire section 16a, the control unit 42 controls the right movement motor 32 and the left movement motor 34 such that the strength of the magnetic field of the guide wire 18 or the first boundary wire section 16a detected by the center front magnetic sensor 60c is zero. This allows the center front magnetic sensor 60c to be positioned directly above the guide wire 18 or the first boundary wire section 16a while the work robot 12 moves.When the strength of the magnetic field of the guide wire 18 or the first boundary wire area 16a detected by the center front magnetic sensor 60c indicates a positive value, which means that the center front magnetic sensor 60c is positioned to the left of the guide wire 18 or the first boundary wire area 16a, the control unit 42 controls the left movement motor 34 to rotate at a faster speed than the right movement motor 32. As a result, the work robot 12 turns to the right (turns right).When the magnetic field strength of the guide wire 18 or the first boundary wire section 16a detected by the center front magnetic sensor 60c indicates a negative value, meaning that the center front magnetic sensor 60c is positioned to the right of the guide wire 18 or the first boundary wire section 16a, the control unit 42 controls the right movement motor 32 to rotate at a faster speed than the left movement motor 34. As a result, the work robot 12 turns left (turns left). Furthermore, the control unit 42 controls the right movement motor 32 and the left movement motor 34 so that the magnetic field strength detected by the rear magnetic sensor 60d is a positive value.

[0069] In S206 of Fig. 12, the control unit 42 determines whether the rear magnetic sensor 60d has crossed the boundary wire 16 (i.e., the first boundary wire area 16a and the second boundary wire area 16b). The control unit 42 determines that the rear magnetic sensor 60d has crossed the boundary wire 16 when the strength of the magnetic field of the boundary wire 16 detected by the rear magnetic sensor 60d has changed from a positive value to a negative value. In S206, the control unit 42 obtains the strength of the magnetic field of the boundary wire 16 from a magnetic sensor 60 that is different from the magnetic sensor 60 used in S202. If the control unit 42 determines that the rear magnetic sensor 60d has crossed the boundary wire 16 (YES in S206), the process proceeds to S208.

[0070] In S208, the control unit 42 controls the right movement motor 32 and the left movement motor 34 such that the work robot 12 moves in a return direction D4 along the boundary wire 16 (ie, the first boundary wire area 16a and the second boundary wire area 16b). As shown in Fig. As shown in Figure 1, the return direction D4 is counterclockwise. The return direction D4 is the same as the direction of the current flowing in the boundary wire 16.

[0071] As in Fig. 14, while the work robot 12 moves in the return direction D4 along the boundary wire 16, the control unit 42 controls the right movement motor 32 and the left movement motor 34 such that the strength of the magnetic field of the boundary wire 16 detected by the right front magnetic sensor 60a is zero. This allows the right front magnetic sensor 60a to be positioned directly above the boundary wire 16 while the work robot 12 moves. This positioning of the right front magnetic sensor 60a directly above the boundary wire 16 minimizes an area of ​​the work robot 12 that protrudes to the outside of the work area WA, compared to a configuration in which a magnetic sensor 60 other than the right front magnetic sensor 60a is positioned directly above the boundary wire 16. In a modification, if the return direction D4 (see Fig. 1) the direction is clockwise, the control unit 42 controls the right movement motor 32 and the left movement motor 34 such that the strength of the magnetic field of the boundary wire 16 detected by the left front magnetic sensor 60b is zero. The right front magnetic sensor 60a, positioned immediately above the boundary wire 16 in S208, is different from the center front magnetic sensor 60c, positioned immediately above the guide wire 18 or the first boundary wire area 16a in S204. When the strength of the magnetic field of the boundary wire 16 detected by the right front magnetic sensor 60a indicates a positive value, meaning that the right front magnetic sensor 60a is positioned to the left of the boundary wire 16, the control unit 42 controls the left movement motor 34 to rotate at a faster speed than the speed of the right movement motor 32.As a result, the work robot 12 turns to the right. If the strength of the magnetic field of the boundary wire 16, detected by the right front magnetic sensor 60a, indicates a negative value, meaning that the right front magnetic sensor 60a is positioned to the right of the boundary wire 16, the control unit 42 controls the right movement motor 32 to rotate at a faster speed than the left movement motor 34. As a result, the work robot 12 turns to the left. Furthermore, the control unit 42 controls the right movement motor 32 and the left movement motor 34 so that the strength of the magnetic field detected by the left front magnetic sensor 60b indicates a positive value.

[0072] As in Fig. 10, in S10 to S8, the control unit 42 determines whether one or more magnetic field strengths of the first loop region 82 detected by the magnetic detection unit 40 are equal to or greater than the threshold value. In making this determination, the control unit 42 may use only the magnetic field strength detected by the magnetic sensor 60 used to determine the threshold value (which may be referred to as the magnetic sensor 60'), the magnetic field strengths detected by the magnetic sensors 60 other than the magnetic sensor 60', or the magnetic field strengths detected by two or more of the magnetic sensors 60. In a modification, the control unit 42 may monitor one or more magnetic field strengths of the second loop region 84 detected by the magnetic detection unit 40.If the control unit 42 determines that the one or more magnetic field strengths of the first loop region 82 detected by the magnetic detection unit 40 are equal to or greater than the threshold (YES in S10), the process proceeds to a docking process in S12. If it is determined that the one or more magnetic field strengths of the first loop region 82 detected by the magnetic detection unit 40 are less than the threshold (NO in S10), the control unit 42 continues to move the work robot 12 in the return direction D3, D4 until it determines that the one or more magnetic field strengths of the first loop region 82 detected by the magnetic detection unit 40 are equal to or greater than the threshold.

[0073] In S302 of the docking process, which is Fig. 15, the control unit 42 controls the right movement motor 32 and the left movement motor 34 such that the work robot 12 moves along the first loop region 82 based on one or more strengths of the magnetic field of the first loop region 82 detected by the magnetic detection unit 40. As shown in Fig. 16, in S302 the work robot 12 moves clockwise along the first loop area 82.

[0074] In S304 of Fig. 15, the control unit 42 determines whether the work robot 12 has reached the center position of the charging station 14 based on the one or more magnetic field strengths of the first loop area 82 detected by the magnetic detection unit 40. The center position of the charging station 14 is a position at which the magnetic field strength of the station wire 20 is zero, that is, the center position of the charging station 14 is the boundary between the first loop area 82 and the second loop area 84. If the control unit 42 determines that the work robot 12 has reached the center position of the charging station 14 (YES in S304), the process proceeds to S306. As shown in Fig. 16, in S304, the front end of the work robot 12 is positioned near the boundary between the first loop area 82 and the second loop area 84.

[0075] In S306 of Fig. 15, the control unit 42 controls the right movement motor 32 and the left movement motor 34 such that the right movement motor 32 rotates in the forward direction (or the reverse direction) and the left movement motor 34 rotates in the reverse direction (or the forward direction), so that the work robot 12 rotates in place. When the work robot 12 has rotated over a predetermined angle, the control unit 42 stops the right movement motor 32 and the left movement motor 34. As shown in Fig. 16, in S306, the front end of the work robot 12 moves away from the boundary between the first loop area 82 and the second loop area 84.

[0076] In S308 of Fig. 15, the control unit 42 controls the right movement motor 32 and the left movement motor 34 to move and rotate the work robot 12. As in Fig. As shown in Figure 16, in S308, the work robot 12 first moves forward and then turns in place. This adjusts the orientation of the work robot 12 relative to the charging station 14.

[0077] In S310 of Fig. 15, the control unit 42 determines whether the one or more magnetic field strengths detected by the magnetic detection unit 40 are zero. If the control unit 42 determines that the one or more magnetic field strengths detected by the magnetic detection unit 40 are zero (YES in S310), the process proceeds to S312. As shown in Fig. 16, in S310, the charging interface 48 is positioned over the boundary between the first loop region 82 and the second loop region 84 so as to face the charging port 74 of the charging station 14.

[0078] In S312 of Fig. 15, the control unit 42 controls the right movement motor 32 and the left movement motor 34 to rotate in the forward direction at the same speed, so that the work robot 12 moves forward. As a result, the work robot 12 approaches the charging port 74.

[0079] In S314, the control unit 42 determines whether the charging interface 48 has docked with the charging port 74. If the control unit 42 determines that the charging interface 48 has docked with the charging port 74 (YES in S314), the process proceeds to S316.

[0080] In S316, the control unit 42 stops the right movement motor 32 and the left movement motor 34. As in Fig. 16, in S316 the working robot 12 stops with the charging interface 48 docked to the charging port 74.

[0081] (Avoidance process) The working robot 12 may pass near the charging station 14 during the mowing process in S4. In this case, the control unit 42 executes an avoidance process which is Fig. 17, to prevent the working robot 12 from colliding with the charging station 14.

[0082] As in Fig. As shown in Figure 17, in S402 of the avoidance process, the control unit 42 determines whether one or more magnetic field strengths of the first loop region 82 detected by the magnetic detection unit 40 are equal to or greater than a threshold. If the control unit 42 determines that the one or more magnetic field strengths of the first loop region 82 detected by the magnetic detection unit 40 are equal to or greater than the threshold (YES in S402), the process proceeds to S404.

[0083] In S404, the control unit 42 stops the right movement motor 32 and the left movement motor 34. The work robot 12 is thereby stopped.

[0084] In S406, the control unit 42 controls the right movement motor 32 to rotate in the forward direction (or the reverse direction) and controls the left movement motor 34 to rotate in the reverse direction (or the forward direction), so that the work robot 12 rotates in place. When the work robot 12 has rotated over a predetermined angle, the control unit 42 stops the right movement motor 32 and the left movement motor 34. The predetermined angle can be set, for example, for each rotation.

[0085] In S408, the control unit 42 controls the right movement motor 32 and the left movement motor 34 to rotate in the forward direction so that the work robot 12 moves away from the charging station 14.

[0086] (Effects) The autonomous movement system 10 according to the embodiment includes the work robot 12 configured to perform a work operation while autonomously moving within the work area WA, the charging station 14 configured to charge the work robot 12, the boundary wire 16 defining the work area WA, the boundary wire 16 generating a magnetic field when a current flows in the boundary wire 16, and the station wire 20 disposed at the charging station 14 and electrically connected to the boundary wire 16, the station wire 20 generating a magnetic field when a current flows in the station wire 20.The work robot 12 includes the work unit 30 configured to perform the work operation, the work motor 28 configured to drive the work unit 30, the movement unit 36 ​​configured to move the work robot 12, the movement motors 32, 34 configured to drive the movement unit 36, the battery 46 configured to be charged at the charging station 14 and to supply power to the work motor 28 and the movement motors 32, 34, the magnetic detection unit 40 configured to detect the magnetic field generated by the boundary wire 16 and the magnetic field generated by the station wire 20, and the control unit 42 configured to control the work motor 28 and the movement motors 32, 34 and to control the station wire 20 based on a detection result by the magnetic detection unit. 40 to be recorded.The charging station 14 includes the charging port 74 configured to be electrically connected to the working robot 12 and the signal generator 76 configured to supply the identical first electrical signal (an example of an electrical signal) to the boundary wire 16 and the station wire 20.

[0087] According to the configuration described above, the single signal generator 76 supplies the identical first electrical signal to the boundary wire 16 and the station wire 20. This enables detection of the station wire 20 using the simple configuration of the charging station 14.

[0088] The station wire 20 has the magnetic field enhancement structure 80 configured to generate, when a current flows in the station wire 20, the magnetic field having a higher strength than a strength of the magnetic field generated by the boundary wire 16 when a current flows in the boundary wire 16.

[0089] In the configuration described above, the strength of the magnetic field generated by the station wire 20 is higher than the strength of the magnetic field generated by the boundary wire 16. This facilitates the detection of the station wire 20.

[0090] The control unit 42 is configured to detect the station wire 20 based on at least the strength of the magnetic field generated by the station wire 20 when a current flows in the station wire 20.

[0091] The configuration described above enables the detection of the station wire 20 with the simple configuration that uses the magnetic field strength.

[0092] The station wire 20 is electrically connected in series with the boundary wire 16.

[0093] The configuration described above allows the identical first electrical signal to be supplied to the boundary wire 16 and the station wire 20 using the simple configuration.

[0094] The control unit 42 is configured to store a strength of the magnetic field of the station wire 20 when the work robot 12 is located at the charging station 14, and to detect the station wire 20 based on the stored strength of the magnetic field and the strength of the magnetic field of the station wire 20 detected by the magnetic detection unit 40.

[0095] The configuration described above enables more accurate detection of the station wire 20, compared to configurations in which the control unit 42 does not store the strength of the magnetic field of the station wire 20 when the work robot is at the charging station, such as a configuration in which the strength of the magnetic field is stored in advance during the manufacture of the work robot 12, a configuration in which the strength of the magnetic field is set by a user, etc.

[0096] The control unit 42 is configured to execute the separation process of S2 for separating the work robot 12, which is electrically connected to the charging port 74, from the charging station 14, and to obtain the strength of the magnetic field of the station wire 20 after the work robot 12 is separated from the charging port 74 during the separation process of S2.

[0097] In a configuration where the control unit 42 obtains the strength of the magnetic field of the station wire 20 before the work robot 12 is disconnected from the charging port 74, the control unit 42 needs to obtain the strength of the magnetic field of the station wire 20 while determining whether or not the work robot 12 has been disconnected from the charging port 74. The above-described configuration allows the control unit 42 to determine whether the work robot 12 has been disconnected from the charging port 74 and separately obtain the strength of the magnetic field of the station wire 20.

[0098] The separation process of S2 includes the rotation process of S108 for rotating the work robot 12 after it has been separated from the charging port 74. The control unit 42 is configured to maintain the strength of the magnetic field of the station wire 20 during the rotation process of S108.

[0099] In the above-described configuration in which the work robot 12 rotates, the distance between the work robot 12 and the charging station 14 is less likely to change compared to a configuration in which the work robot 12 moves straight away from the charging station 14. Since the control unit 42 receives the strength of the magnetic field of the station wire 20 during the rotation process, changes in the strength of the magnetic field are small compared to a configuration in which the control unit 42 receives the strength of the magnetic field of the station wire 20 while the work robot 12 moves straight away from the charging station 14.

[0100] The magnetic detection unit 40 includes the plurality of magnetic sensors 60 configured to detect the magnetic field generated by the boundary wire 16 and the magnetic field generated by the station wire 20. The control unit 42 is configured to receive the strengths of the magnetic field of the station wire 20 detected by the plurality of magnetic sensors 60 during the rotation process of S108.

[0101] The configuration described above enables the detection of the station wire 20 even if one of the plurality of magnetic sensors 60 is defective.

[0102] The control unit 42 is configured to store the peak strength of the magnetic field of the station wire 20.

[0103] The configuration described above enables accurate detection of the station wire 20 using the peak strength of the magnetic field of the station wire 20.

[0104] The control unit 42 is configured to set a threshold equal to or greater than 80% of the stored peak strength and detect the station wire 20 based on the set threshold and the strength of the magnetic field of the station wire 20 detected by the magnetic detection unit 40.

[0105] The strength of the magnetic field detected by the magnetic detection unit 40 decreases as the distance between the work robot 12 and the station wire 20 increases. Since the threshold is set as a predetermined proportion of the peak strength of the magnetic field, the above-described configuration enables detection of the station wire 20 even when the work robot 12 is away from the station wire 20.

[0106] The station wire 20 includes the first loop region 82, which is configured to increase an absolute value of a positive value of the strength of the magnetic field of the station wire 20, and the second loop region 84, which is configured to increase an absolute value of a negative value of the strength of the magnetic field of the station wire 20. The control unit 42 is configured to control the movement motors 32, 34 based on the strength of the magnetic field generated by the first loop region 82 to move the work robot 12 along the first loop region 82.

[0107] In general, the station wire 20 is detected more accurately in a configuration in which the control unit 42 detects the station wire 20 based on the positive value of the magnetic field strength than in a configuration in which the control unit 42 detects the station wire 20 based on the negative value of the magnetic field strength. With the above-described configuration, the strength of the magnetic field generated by the first loop region 82 is utilized, and thus the work robot 12 can be moved accurately along the first loop region 82.

[0108] The control unit 42 is configured to execute the docking process of S102 for electrically connecting the work robot 12 to the charging port 74 when the control unit 42 detects the station wire 20 while the work robot 12 is returning to the charging station 14.

[0109] If the docking process is performed according to methods different from the method that detects the station wire 20, for example, in response to a GPS detecting the position of the work robot 12, the work robot 12 may collide with the charging station 14 before the docking process is performed because the detected position of the work robot 12 may be different from the current position of the work robot 12. With the configuration described above, the docking process is performed in response to the detection of the station wire 20, and thus the collision of the work robot 12 with the charging station 14 can be prevented.

[0110] The control unit 42 is configured to execute the movement direction changing process of S404, S406, S408 for changing the movement direction of the work robot 12 when the control unit 42 detects the station wire 20 while the work robot 12 is performing the work operation.

[0111] The configuration described above prevents the working robot 12 from colliding with the charging station 14.

[0112] (Modifications) In one embodiment, the work robot 12 may be a cleaning device configured to remove foreign material, such as dust, from a floor.

[0113] In one embodiment, the battery 46 of the work robot 12 may be removable from the housing 24.

[0114] In one embodiment, the moving unit 36 ​​of the working robot 12 may have crawler tracks instead of the right front auxiliary wheel 52, the left front auxiliary wheel 54, the right rear drive wheel 56, and the left rear drive wheel 58.

[0115] In one embodiment, the station wire 20 may be electrically connected in parallel with the boundary wire 16.

[0116] In one embodiment, during the separation process, the control unit 42 may obtain the strength of the magnetic field of the station wire 20 before the work robot 12 is separated from the charging port 74.

[0117] In one embodiment, in the return process, the magnetic sensor 60 used in S204 may be the same as the magnetic sensor 60 used in S206.

[0118] In one embodiment, S404 may be omitted from the avoidance process.

[0119] In one embodiment, the threshold value set in S 114 of the separation process may be 50% or greater of the stored peak strength.

[0120] In one embodiment, the control unit 42 may detect the station wire 20 based on the strength of the magnetic field of the station wire 20, which is detected when a current flows therein, and a degree of correlation (i.e., a degree of coincidence) between a waveform of an electrical signal applied to the signal generator 76 and a waveform of the detected magnetic field. Alternatively, the control unit 42 may detect the station wire 20 based on a sum of the products of the degree of correlation and the strength of the detected magnetic field, calculated for a predetermined period of time. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2017 - 182 635 A

[0002]

Claims

[1] Autonomous movement system (10), with a work robot (12) configured to perform a work operation while moving autonomously within a work area (WA), a charging station (14) configured to charge the working robot (12), a boundary wire (16) defining the working area (WA), in which the boundary wire (16) generates a magnetic field when a current flows in the boundary wire (16), and a station wire (20) arranged at the charging station (14) and electrically connected to the boundary wire (16), wherein the station wire (20) generates a magnetic field when a current flows in the station wire (20), in which the work robot (12), a work unit (30) configured to perform the work process, a working motor (28) configured to drive the working unit (30), a movement unit (36) configured to move the working robot (12), a movement motor (32, 34) configured to drive the movement unit (36), a battery (46) configured to be charged by the charging station (14) and to supply power to the working motor (28) and the movement motor (32, 34), a magnetic detection unit (40) configured to detect the magnetic field generated by the boundary wire (16) and the magnetic field generated by the station wire (20), and a control unit (42) configured to control the working motor (28) and the moving motor (32, 34) and to detect the station wire (20) based on a detection result by the magnetic detection unit (40), and the charging station (14), a charging port (74) configured to be electrically connected to the work robot (12), and a signal generator (76) configured to supply an identical electrical signal to the boundary wire (16) and the station wire (20). [2] The autonomous movement system (10) according to claim 1, wherein the station wire (20) comprises a magnetic field enhancement structure (80) configured to generate, when a current flows in the station wire (20), the magnetic field having a higher strength than a strength of the magnetic field generated by the boundary wire (16) when a current flows in the boundary wire (16). [3] Autonomous movement system (10) according to claim 1 or 2, wherein the control unit (42) is configured to detect the station wire (20) based on at least a strength of the magnetic field generated by the station wire (20) when a current flows in the station wire (20). [4] Autonomous movement system (10) according to one of claims 1 to 3, wherein the station wire (20) is electrically connected in series with the boundary wire (16). [5] Autonomous movement system (10) according to one of claims 1 to 4, wherein the control unit (42) is configured to to store a strength of the magnetic field of the station wire (20) when the working robot (12) is at the charging station (14), and detect the station wire (20) based on the stored strength of the magnetic field and the strength of the magnetic field of the station wire (20) detected by the magnetic detection unit (40). [6] Autonomous movement system (10) according to claim 5, wherein the control unit (42) is configured to to carry out a separation process (S2) to separate the working robot (12), which is electrically connected to the charging port (74), from the charging station (14), and to obtain the strength of the magnetic field of the station wire (20) after the work robot (12) has been separated from the charging port (74) during the separation process (S2). [7] Autonomous movement system (10) according to claim 6, wherein the separation process (S2) comprises a rotation process (S108) for rotating the working robot (12) after separation from the charging port (74), and the control unit (42) is configured to maintain the strength of the magnetic field of the station wire (20) during the turning process (S108). [8] Autonomous movement system (10) according to claim 7, wherein the magnetic detection unit (40) comprises a plurality of magnetic sensors (60) configured to detect the magnetic field generated by the boundary wire (16) and the magnetic field generated by the station wire (20), and the control unit (42) is configured to receive strengths of the magnetic field of the station wire (20) detected by the plurality of magnetic sensors (60) during the turning process (108). [9] Autonomous movement system (10) according to one of claims 5 to 8, wherein the control unit (42) is configured to store a peak value of the strength of the magnetic field of the station wire (20). [10] Autonomous movement system (10) according to claim 9, wherein the control unit (42) is configured to to set a threshold equal to or greater than 80% of the stored peak value, and detect the station wire (20) based on the set threshold value and the strength of the magnetic field of the station wire (20) detected by the magnetic detection unit (40). [11] Autonomous movement system (10) according to one of claims 1 to 10, wherein the station wire (20) a first loop region (82) configured to increase an absolute value of a positive value of the strength of the magnetic field of the station wire (20), and a second loop region (84) configured to increase an absolute value of a negative value of the strength of the magnetic field of the station wire (20), and the control unit (42) is configured to control the movement motor (32, 34) based on the strength of the magnetic field generated by the first loop region (82) to move the work robot (12) along the first loop region (82). [12] Autonomous movement system (10) according to one of claims 1 to 11, wherein the control unit (42) is configured to execute a docking process (102) for electrically connecting the work robot (12) to the charging port (74) when the control unit (42) detects the station wire (20) while the work robot (12) is returning to the charging station (14). [13] The autonomous movement system (10) according to any one of claims 1 to 12, wherein the control unit (42) is configured to execute a movement direction changing process (S404, S406, S408) for changing a movement direction of the work robot (12) when the control unit (42) detects the station wire (20) while the work robot (12) is performing the work operation.

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