System and method for controlling a self-propelling lawnmower

A method performed by a system for controlling a self-propelling lawnmower, the system comprising the self-propelling lawnmower having a control unit and at least one sensor, a boundary wire and a signal generator and wherein the self-propelling lawnmower is configured to move across an area surrounded by the boundary wire, the method comprising:

• encoding, by means of the signal generator, a data frame with a recognition code in an alternating current that is Direct Current, DC-balanced, the recognition code comprising a system code and a loop number code,
• randomly transmitting within a predetermined period of time, by means of the signal generator, the data frame in form of a burst to the boundary wire,
• receiving, in the self-propelling lawnmower, the randomly transmitted data frame burst, by means of the at least one sensor,
• decoding, in the control unit, the received data frame to retrieve the recognition code, i.e. the system code and the loop number code,
• determining, in the control unit, that the loop number code relates to the boundary wire,
• comparing, in the control unit, the decoded system code with a predetermined system code stored in a memory of the control unit, and
• determining that the lawnmower is on the inside of the boundary wire if the decoded system code matches the predetermined system code, or
• determining that the lawnmower is on the outside of the boundary wire if the decoded system code matches the inverse of the predetermined system code.

A system for controlling a self-propelling lawnmower to move across an area surrounded by a boundary wire, comprising the self-propelling lawnmower, the boundary wire and a signal generator, the lawnmower further comprising a control unit and at least one sensor, wherein the control unit comprises a processor and a memory and wherein the signal generator comprises a processor and a memory, the memories comprising instructions which when executed by the processers cause the system to:

• encode, in the signal generator, a data frame with a recognition code in an alternating current that is Direct Current, DC-balanced, the recognition code comprising a system code and a loop number code,
• randomly transmit, within a predetermined period of time, the data frame in form of a burst from the signal generator to the boundary wire,
• receive, in the self-propelling lawnmower, the randomly transmitted data frame burst, by means of the at least one sensor,
• decode, in the control unit, the received data frame to retrieve the recognition code, i.e. the system code and the loop number code,
• determine, in the control unit, that the loop number code relates to the boundary wire,
• compare, in the control unit, the decoded system code with a predetermined system code stored in the memory of the control unit, and
• determine that the lawnmower is on the inside of the boundary wire if the decoded system code matches the predetermined system code, or
• determine that the lawnmower is on the outside of the boundary wire if the decoded system code matches the inverse of the predetermined system code.