Re: [mowbot] Husqvana Solar Mower

robin nospam at
Wed, 9 Oct 1996 01:01:34 +0100

Dave Everett wrote:
> The 50deg was part of a nature strip. It would seem stupid if a lawn was
> considered off limits to Mowbot because part of it was difficult. 50deg
> can be dealt with, Mowbot doesn't have to travel on the slope, it could
> be travelling sideways along the the slope.
I think that even travelling sideways along such a slope would be
hazardous. If this were a design requirement, we'd have to make the
centre of gravity sufficiently low and probably have explicit zig-zag
slope-climbing behaviour (or more powerful motors). Do we need to
do this? What is the steepest slope we should require of the design?

> > > It has no memory of where it has cut. The mower is totally random,
> > > except when it reaches long grass, it then cuts the patch in a square
> > > pattern much as the Lawnranger did.
> It seems sound to me, except for the fact that it has to run into long
> grass just by luck, it can't seek it out, and it has no way of knowing
> if it's covered all areas.
It sounds as if the algorithm uses just two modes, one random search and
one organised behaviour. The change over from random to patterned occurs
when the grass sensor triggers on ``long'' grass. The pattern behaviour
is some sort of flood-fill, again influenced and ultimately terminated by
readings from the grass sensor. If deposited in an area with uniformly
uncut grass, I can see this working well. And as long as the length
sensor has some hysteresis (so it is hard to enter pattern-mode but
easy to stay there), and the pattern-mode does a competent flood-fill,
I can see it working in a steady state situation too. But I'd like to
get a feel for how good this strategy is without building it, so I'd
like to see what happens in simulation. Has anyone got any suitable
tools to knock up such a thing?


Copyright (C) 1996 R.M.O'Leary <robin nospam at>  All rights reserved.
For licence to copy, see