Robotic mower and method, system and device of path planning thereof

A robotic mower, comprising:

• a body,
• at least one sensor arranged at a front end of the body, and
• a control unit, arranged on the body, the control unit comprising a processor and a memory coupled to each other, wherein the memory stores program instructions, when the program instructions stored in the memory are executed by the processor, the control unit is capable of:
• exiting a charging station,
• finding a boundary wire or a guide wire, wherein the boundary wire is pre-laid on an edge of a working area and the guide wire is pre-laid in the working area, and
• following the boundary wire or the guide wire to move until the robotic mower reaches a predetermined destination, comprising:
• straddling along the boundary wire in a first direction until the robotic mower finds a straight boundary section of the boundary wire,
• moving backward on and along the straight boundary section of the boundary wire in a direction opposite to the first direction by a second random backward distance, the second random backward distance being less than or equal to a length of the straight boundary section, and
• rotating a second preset angle toward a center of the working area to adjust a moving direction of the robotic mower, the second preset angle being less than 180 degrees,
• moving forward until a distance between the robotic mower and the boundary wire is a first preset distance, the first preset distance being a random value;
• rotating the second preset angle back to keep a moving direction of the robotic mower parallel to the boundary wire or the guide wire, the distance between the robotic mower and the boundary wire still being the first preset distance, and
• following the boundary wire at the first preset distance until the robotic mower reaches the predetermined destination, the distance between the robotic mower and the boundary wire remaining the first preset distance when following the boundary wire at the first preset distance, wherein
• the boundary wire defines an outer boundary loop and an inner boundary loop, a charging station loop substantially defines a position of the charging station, the charging station loop and the inner boundary loop each is arranged inside the charging station, the outer boundary loop defines the boundary of the working area, the charging station is arranged on the outer boundary loop and shares a common edge with the outer boundary loop and the inner boundary loop, the boundary wire is recessed into the working area at the position of the charging station to define the inner boundary loop,
• the inner boundary loop is narrower than the charging station loop, passed through and intersected with the charging station loop, and configured to guide the robotic mower to exit the charging station, and
• pulse current signals are input to the boundary wire, the guide wire and the charging station loop respectively in an interval manner to produce corresponding guiding signals in different time intervals, the outer boundary loop and the inner boundary loop both are defined by the boundary wire and produce same guiding signals.