Autonomous movement system

1 . An autonomous movement system comprising:

a working robot configured to perform an operation while moving autonomously in a working area;

a charging station configured to charge the working robot;

a boundary wire defining the working area, wherein the boundary wire is configured to generate a magnetic field when a current flows in the boundary wire; and

a station wire at the charging station and electrically connected to the boundary wire, wherein the station wire is configured to generate a magnetic field when a current flows in the station wire,

wherein

the working robot comprises:

a working unit configured to perform the operation;

a working motor configured to drive the working unit;

a movement unit comprising wheels configured to move the working robot;

a movement motor configured to drive the movement unit;

a battery configured to be charged at the charging station and supply power to the working motor and the movement motor;

a magnetic detecting unit comprising a sensor configured to detect the magnetic field generated by the boundary wire and the magnetic field generated by the station wire; and

a control unit comprising a microcomputer configured to control the working motor and the movement motor and detect the station wire based on a detection result by the magnetic detecting unit;

the working unit is fixed to an output shaft of the working motor and is configured to operate by a rotation of the output shaft;

the charging station comprises:

a charging terminal configured to be electrically connected to the working robot; and

a signal generator configured to supply an identical electric signal to the boundary wire and the station wire,

a current waveform and a phase of the electric signal supplied to the station wire are identical to a current waveform and a phase of the electric signal supplied to the boundary wire, and

the station wire is electrically connected in series to the boundary wire.

2 . The autonomous movement system according to claim 1 , wherein the station wire comprises a magnetic field enhancing structure configured to generate, when a current flows in the station wire, the magnetic field with a higher intensity than an intensity of the magnetic field generated by the boundary wire when a current flows in the boundary wire.

3 . The autonomous movement system according to claim 2 , wherein

the control unit is configured to detect the station wire based at least on intensity of the magnetic field generated by the station wire when a current flows in the station wire,

the station wire is electrically connected in series to the boundary wire,

the control unit is configured to:

store intensity of the magnetic field of the station wire when the working robot is at the charging station;

detect the station wire based on the stored intensity of the magnetic field and the intensity of the magnetic field of the station wire detected by the magnetic detecting unit;

execute a separation process to separate the working robot electrically connected to the charging terminal from the charging station; and

obtain the intensity of the magnetic field of the station wire after the working robot has been separated from the charging terminal during the separation process,

the separation process comprises a turn process to turn the working robot after separated from the charging terminal,

the control unit is configured to obtain the intensity of the magnetic field of the station wire during the turn process,

the magnetic detecting unit comprises a plurality of magnetic sensors configured to detect the magnetic field generated by the boundary wire and the magnetic field generated by the station wire,

the control unit is configured to:

obtain intensities of the magnetic field of the station wire detected by the plurality of magnetic sensors during the turn process;

store a peak value of the intensity of the magnetic field of the station wire;

set a threshold value equal to or more than 80% of the stored peak value; and

detect the station wire based on the set threshold value and the intensity of the magnetic field of the station wire detected by the magnetic detecting unit,

the station wire comprises:

a first loop portion configured to increase an absolute value of a positive value of intensity of the magnetic field of the station wire; and

a second loop portion configured to increase an absolute value of a negative value of intensity of the magnetic field of the station wire,

the control unit is configured to:

control the movement motor based on the intensity of magnetic field generated by the first loop portion to move the working robot along the first loop portion;

execute a docking process to electrically connect the working robot to the charging terminal when the control unit detects the station wire while the working robot is returning to the charging station; and

execute a movement direction changing process to change a movement direction of the working robot when the control unit detects the station wire while the working robot is performing the operation.

4 . The autonomous movement system according to claim 1 , wherein the control unit is configured to detect the station wire based at least on intensity of the magnetic field generated by the station wire when a current flows in the station wire.

5 . The autonomous movement system according to claim 1 , wherein

the control unit is configured to:

store intensity of the magnetic field of the station wire when the working robot is at the charging station; and

detect the station wire based on the stored intensity of the magnetic field and the intensity of the magnetic field of the station wire detected by the magnetic detecting unit.

6 . The autonomous movement system according to claim 5 , wherein

the control unit is configured to:

execute a separation process to separate the working robot electrically connected to the charging terminal from the charging station; and

obtain the intensity of the magnetic field of the station wire after the working robot has been separated from the charging terminal during the separation process.

7 . The autonomous movement system according to claim 6 , wherein

the separation process comprises a turn process to turn the working robot after separated from the charging terminal, and

the control unit is configured to obtain the intensity of the magnetic field of the station wire during the turn process.

8 . The autonomous movement system according to claim 7 , wherein

the magnetic detecting unit comprises a plurality of magnetic sensors configured to detect the magnetic field generated by the boundary wire and the magnetic field generated by the station wire, and

the control unit is configured to obtain intensities of the magnetic field of the station wire detected by the plurality of magnetic sensors during the turn process.

9 . The autonomous movement system according to claim 5 , wherein the control unit is configured to store a peak value of the intensity of the magnetic field of the station wire.

10 . The autonomous movement system according to claim 9 , wherein

the control unit is configured to:

set a threshold value equal to or more than 80% of the stored peak value; and

detect the station wire based on the set threshold value and the intensity of the magnetic field of the station wire detected by the magnetic detecting unit.

11 . The autonomous movement system according to claim 1 , wherein

the station wire comprises:

a first loop portion comprising a first portion of a wire wound more than once and configured to increase an absolute value of a positive value of intensity of the magnetic field of the station wire; and

a second loop portion comprising a second portion of the wire wound more than once and configured to increase an absolute value of a negative value of intensity of the magnetic field of the station wire, and

the control unit is configured to control the movement motor based on the intensity of magnetic field generated by the first loop portion to move the working robot along the first loop portion.

12 . The autonomous movement system according to claim 11 , wherein

the first loop portion and the second loop portion are adjacent to each other,

the charging terminal is located on a boundary between the first loop portion and the second loop portion,

a current flows in the first loop portion in one of a clockwise direction and a counterclockwise direction, and

a current flows in the second loop portion in another of the clockwise direction and the counterclockwise direction.

13 . The autonomous movement system according to claim 12 , wherein

the control unit is configured to execute a docking process to electrically connect the working robot to the charging terminal when the control unit detects the station wire while the working robot is returning to the charging station, and

in the docking process, the control unit controls to move the working robot along the first loop portion, to move the working robot on the boundary between the first loop portion and the second loop portion, and to electrically connect the working robot to the charging terminal.

14 . The autonomous movement system according to claim 1 , wherein the control unit is configured to execute a docking process to electrically connect the working robot to the charging terminal when the control unit detects the station wire while the working robot is returning to the charging station.

15 . The autonomous movement system according to claim 1 , wherein the control unit is configured to execute a movement direction changing process to change a movement direction of the working robot when the control unit detects the station wire while the working robot is performing the operation.