Robot lawn mower

Using just a web cam and visual landmarks, robotic lawnmowers could guide themselves around the backgarden.

A Queensland University of Technology PhD researcher has developed a prototype of an inexpensive robotic lawnmower that uses a web cam to guide itself around a backgarden.

Information Technology researcher Henry Huang said existing automatic lawnmowers were expensive and required a guide-wire to be installed around the perimeter of a garden, either above or below ground.

‘My system uses an onboard web cam connected to a computer to detect landmarks placed on the lawn and guides the mower between them,’ Mr Huang said. To study the effectiveness of his system, Huang used traffic cones as landmarks because their colour contrasted well against the green background of the lawn.

Huang said the average lawn required four to five landmarks, while complicated boundaries might need more. The landmarks can be easily relocated to define new working areas.

‘Existing automatic lawnmower kits cost about $2000 including perimeter wires, but my system would be about half that price because the cameras are inexpensive and the landmarks would be much cheaper to produce than the perimeter wires.’

Huang said his robotic mower would not need any sensors other than the web cam, which is pointed vertically towards a panoramic mirror to give it a 360 degree view of the garden.

‘A challenge in creating the system was getting the computer vision system to identify landmarks in different weather conditions and times of day, because colours change with the light,’ Huang said.

QUT researcher Henry Huang with a miniature version of his robotic lawnmower