[Robotgroup] Drive a Droid proposal... How to detect the "fence"?

[Bryan Bishop]

On Tuesday 08 July 2008, Clendon Gibson wrote:
> If you are good with geometry, then you can put encoders on the
> wheels and calculate your position by dead reckoning.

We discussed this last time the group gathered, and it became apparent 
that the amount of loss and difference due to the wheels turning (and 
so on) is significant to the extent that the encoders will miss 
information from time to time. The buildup would be too much of an 
offset from actual data. 

Though I didn't do any calculations to see if it the buildup would be 
significant within the 30 second period that a user would be driving it 
around -- maybe after 30 seconds the buffers could be purged and it 
could return to home (center) position? 

It's not a matter of time, but rather the moves that are made with the 
spinning and the going forward and backwards, some generating more 
error than others, so it's possible to have somebody walk up and make 
it do weird things to make it damage the 'barrier' etc. before those 30 
seconds are up. 

So, I don't think dead reckoning is going to work.

- Bryan
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