Pondering a Robotic Lawn Mower

Published on 2008-09-13 10:23:00+00:00
Fun   Hardware   robots  

Last weekend my gasoline powered lawn mower died. This prompted a search for a new mower, during which I stumbled upon some of Friendly Robotics' Robomow; a line of battery-powered robotic lawn mowers. Now, I have to admit that for the past 15 years or so, every time I've mowed a lawn, I've thought about the possibilities of a robotic lawn mower, and I'm not at all surprised that there's a company producing these. At first the Robomow seems like a really nice product, but it does a have a couple of major drawbacks that would prevent me from purchasing one: 1. Cost: it's at least $2500. I just can't afford that 2. It requires a low-voltage perimeter wire. 3. It takes a huge, heavy-looking battery.

The first problem is a big one for me (i'm broke), though it's a completely uninteresting problem.

The second problem is the one that really irks me though. The Robomow requires that you install a low-voltage perimeter wire around your yard. Now... if you have a rectangular yard with nothing it it, this may not be that big a deal, but if you have trees or any other obstacles (flowers, gazebos, tool sheds, playground equipment, etc), laying that wire is going to be a lot of work. It just seems like there's enough technology out there that would allow a robotic lawn mower to navigate a yard in a much smarter fashion. If I were to build a robotic mower it just seems that there are a number of options that would allow it to navigate a lawn without the perimeter wire. Now I'm just thinking out loud here, and putting this all into one machine may be cost-prohibitive, but if I were to build my own robotic lawn mower, these are the things I would consider: * GPS: your lawn mower is probably outside. Couldn't a robot "know" its position and stay inside some predefined boundary?

There's got to be a compination of these that would allow a robot to navigate obstacles without using a perimeter wire.

I don't have a solution for the third problem. I like the idea of a quiet electric motor, but batteries are heavy, and (in my opinion) just aren't ideal for a piece of lawn equipment. For now, a small, efficient gasoline engine (small like those in a hand-held weed-eater... I'm not sure how efficient those are, though) might be the best way to go. Solar power may also be a possbility.

I'm also thinking a reel mower might be a better way to actually cut the grass. Could a small motor attached to each wheel provide enough control/power/propulsion to make this work?

(I just bought a Craftsman Reel mower, so I'm curious to see how well it works...)

I guess there's also a number of other significant questions that may need to be addressed when considering robotic lawn care. How do we take care of sticks and leaves? I have lots of trees, so these a big problem for me.

I'm beginning to think we're a number of years away from completely robotic lawn care...

This is a completely unorganized, incompletely thought-out post, but I just wanted to get some ideas out in the open...