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The eBay links did not resolve the question of specific plans but appear to be parts for mowers without any relationship to robotic or remote control mowers.

The specific plans would have to be created since no-one has actually built and published a remote controlled robotic mower. The only other area that might provide you with some insight may possibly be the modification of a motorized wheelchair.

Unless you buy a commercial model, your basically on your own ... I made my own with a couple of high powered DC gear motors, frame tubing from Lowes, a cutting motor with homemade blade, sabertooth motor controller, Handheld transmitter... Basically made it up as I went... Winged it, if it were... So I don't have any plans... Like Doc said, got my ideas from roaming the internet because there isn't much specifically on the topic...

Modifications of a electric wheelchair is a good idea, thanks.

Richard - Thanks for the providing a basic guideline. Any photos of your results?