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From: smith@sctc.com (Rick Smith)
Newsgroups: comp.robotics
Subject: Re: CALM (computer-aided lawn mowing)
Keywords: feasibility, beer
Message-ID: <1991Jun24.150617.12775@sctc.com>
Date: 24 Jun 91 15:06:17 GMT
Article-I.D.: sctc.1991Jun24.150617.12775
References: <1991Jun20.192334.24623@auto-trol.com>
Distribution: usa
Organization: SCTC
Lines: 35

bridon@auto-trol.com (Brian Donahue) writes:

>i have this (maybe ridiculous) idea for a 'automatic' lawn mower.

>For example, would i need some sort of tracking system?  or can i assume
>that for every turn of the wheel the lawn mower goes a certain distance?
>(how accurate can i get w/ no tracking system?)

Well, put it this way. People doing the same thing in large rooms
with slip-resistant rubber wheels on nice, flat floors _can't_ get
by without alternative positioning information. If you get off by
a little bit, then the mowing will be uneven. If you get off by
a lot, then you might find yourself living an unwritten Stephen
King novel.

Since you proposed using a mulching mower, you could start from the
middle of the lawn and work outwards. If you can find some way of
detecting the grass height, then you can use this information to guide
the mower. It could just go back and forth as long as it finds long
grass. Once it runs out of long grass, it stops. Then you come along
and drag it over to some more long grass and start it up again.

You'll want to incorporate some collision avoidance behavior that
coordinates with the grass-cutting behavior. If I were you I'd
take a look at the the stuff that Rod Brooks et al are doing at
the MIT AI lab.

>or is this totally ridiculous & not worth pursuing?

It depends on your goal. Sounds like a fun project even if you 
fail, so long as the mower doesn't chase you down the street,
or mulch any small living things, like children.

Rick.
smith@sctc.com    Arden Hills, Minnesota