Abstract: An electric machine, such as an autonomous vacuum cleaner, is powered through a cable and includes a means or device for detecting the orientation of the cable with respect to the main body of the machine that may be in the form of a pivotable member such as pendulum, connected to a potentiometer. The potentiometer provides an output signal proportional to the position of the free end of the pendulum. Thus, the machine can detect the position of the cable and thus can avoid it or else follow it. Microswitches may also be provided to detect extreme positions of the cable.

Abstract: A control system is provided for navigating an autonomous machine around a working area in a manner that causes the machine to traverse substantially all of the free surface of the working area. The control system is arranged to cause the machine to follow a boundary of the working area and to perform a plurality of movements, each movement comprising the machine travelling away from the boundary of the working area, at an angle to the boundary, and returning again to the boundary. The machine moves along the boundary of the working area between each movement and repeats the movements as the machine follows substantially the entire boundary of the working area.

Abstract: An autonomous machine that needs to establish when it has completed a circuit of a working area includes a main body and a marker such as an annular magnetic puck. The machine includes a control system configured to cause the main body to traverse a working area according to a predetermined sequence. A detector is provided to detect the marker, and either the detector or the marker may be located on the main body. The control system is configured to recognize a predetermined location in the area, or to effect a predetermined part of the sequence, on detecting the marker. Preferably, the marker is slidably located on a power cable for the machine.

Abstract: An autonomous machine explores the area in which it is located, constructing a map of the area based on information collected by the machine as the machine explores the area. The machine determines when it has returned to a previously visited position within the area. The map is corrected when the machine returns to the previously visited position, based on the knowledge that the current position and the previously visited position are the same.