Newsgroups: comp.robotics
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From: ad302@freenet.buffalo.edu (Elizabeth M. Phillips)
Subject: control system problem [RFI? <grin> ]
Message-ID: <CtMnH3.IH6@freenet.buffalo.edu>
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Reply-To: ad302@freenet.buffalo.edu
Organization: State University of New York At Buffalo, NY (USA)
Date: Thu, 28 Jul 1994 01:43:50 GMT
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Hello I have a stability problem I would like to fix on a model flying
wing.  A flying wing has a seveer YAW problem (in 3 space say X and Y
are the viewing plane and Z is depth) this is rotation about the
Y axis.  Sort of like a boomerang (hehehe OUCH).  Well it's anoying.
I was considering using a control system to REACT to user inputs:
1:	to translate "standard" stabalizer/rudder input to elevon movement
2:	to reduce insesant pitch control problems (IE the plane has a 
	tendancy to flip end over end :) 
3:	solve the "boomerang" effect (equally anoying! :)
4:	prevent "sudden" movements that could send the plan out of control

I plan to use on each side a split elevon (IE an independant elevon for
each surface [top and bottom]).  This will allow for air braking as well
as other capabilities.  I'm sure many of you have played with model airplane
servos.

So here is how "I" believe it can be achieved (then you can rip apart my
silly notions and stomp on them! [not that I really need that but ...])
use 12bit D/A convertors as digital trim pots to modulate signals from 
the CPU (likely to be a PIC for size and speed reasons) for each servo,
convert the posistional information into "useful" data for the CPU by
using A/D convertors (12bit) frequency to voltage convertors OR simply 
sampling the data present on the outputs of the reciever at regular 
intervals for the proper resolution.  use strain guages to measure
aceleration (for limiting speed of control surface changes) 

Is thier anything I should consider?  Would using a gyroscope help?

Yes I'm clueless as too exactly how to proceed.  I just want a plane
that doesn't flip or spin in circles :)
-- 
