Never mind... I guess they're real gyros. Pretty cool! Thanks a lot! I
thought Analog only made accelerometers.
Not a bad price either... I only really need roll axis control, since yaw's
not too important and can controlled with a tilt sensor set up as a turn
coordinator, and pitch is controlled by airspeed.



- Robert


----- Original Message -----
From: "Robert Ussery" <uavscience@frii.com>
To: <PICLIST@mitvma.mit.edu>
Sent: Friday, July 25, 2003 6:48 PM
Subject: Re: [PICLIST] Dynamic tilt angle sensor


> Are these gyroscopes or accelerometers?
>
> - Robert
>
>
> ----- Original Message -----
> From: "M. Adam Davis" <adampic@UBASICS.COM>
> To: <PICLIST@mitvma.mit.edu>
> Sent: Friday, July 25, 2003 5:18 PM
> Subject: Re: [PICLIST] Dynamic tilt angle sensor
>
>
> > There are lots of solid state gyros out there:
> > http://www.analogdevices.com/index_noflash.html
> > Click on MEMS Technology, Selection Tables,  and iMEMS. Gyroscopes
> >
>
<http://www.analog.com/Analog_Root/sitePage/mainSectionContent/0,2132,level4
>
%253D%25252D1%2526ContentID%253D14642%2526level1%253D212%2526level2%253D%252
> 52D1%2526level3%253D%25252D1,00.html>
> > for two examples of solid state gyros.
> >
> > Of course, they are $33[USD] each, and you need three for a full three
> > axis gyro, but it's still under the $100 you specified originally... :-)
> >
> > -Adam
> >
> >
> > Robert Ussery wrote:
> >
> > >Thanks, Matt.
> > >I'll give that a try. My only concern with keeping track of bank
through
> > >accelerometers is their drift and lack of sensitivity to low roll
rates.
> I
> > >think it should work, however, as long as roll rates are kept within
the
> > >specs of the accelerometer.
> > >Laser ring gyro's would be great except for $$... Roll my own, mebbe?
:O)
> > >
> > >- Robert
> > >
> > >
> > >----- Original Message -----
> > >From: "Matt Redmond" <mdredmond@CHARTER.NET>
> > >To: <PICLIST@mitvma.mit.edu>
> > >Sent: Friday, July 25, 2003 10:00 AM
> > >Subject: Re: [PICLIST] Dynamic tilt angle sensor
> > >
> > >
> > >
> > >
> > >>Sorry - forgot to change the subject of my earlier reply!
> > >>
> > >>Robert: What you are looking for is gyro inclinometer -
> > >>probably a solid-state gyro inclinometer. Do a Google
> > >>search for "solid state gyro" and/or "gyro inclinometer"
> > >>and you will likely get a bazillion hits. The trick is
> > >>finding one that is cheap!
> > >>
> > >>You /could/ use an accelerometer like the one suggested
> > >>earlier. You would have to keep track of the current bank
> > >>angle (in your microcontroller) at all times. For example,
> > >>the accelerometer won't tell you you /are in/ a standard
> > >>rate turn - but it will have told you earlier that you
> > >>entered it. Since it hasn't told you that you returned to
> > >>wings-level, you know you're still in the turn. AFAIK,
> > >>laser-ring accelerometers were the standard devices used
> > >>in autopilots for many years until GPS was approved
> > >>recently.
> > >>
> > >>-matt
> > >>
> > >>
> > >>
> > >>
> > >>Sorta, except that it's (AFAIK) just an accelerometer and
> > >>won't tell you
> > >>angle relative to the horizon in a dynamic situation.
> > >>I.e., if you're in a
> > >>coordinated 1 G turn, it'll tell you you're level, whereas
> > >>you will have
> > >>approximately a 60 degree bank. My question dealt with how
> > >>you can measure
> > >>tilt in a dynamic, not a static situation.
> > >>In "real" aircraft, a mechanical gyro remains level with
> > >>the horizon, no
> > >>matter what position the airframe takes relative to the
> > >>horizon. I want to
> > >>duplicate this in a UAV without the expense of a full-up
> > >>mechanical gyro
> > >>system.
> > >>
> > >>
> > >>
> > >>- Robert
> > >>
> > >>
> > >>--
> > >>
> > >>http://www.piclist.com#nomail Going offline? Don't
> > >>AutoReply us!
> > >>
> > >>email listserv@mitvma.mit.edu with SET PICList DIGEST in
> > >>the body
> > >>
> > >>--
> > >>http://www.piclist.com hint: To leave the PICList
> > >>mailto:piclist-unsubscribe-request@mitvma.mit.edu
> > >>
> > >>
> > >>
> > >
> > >--
> > >http://www.piclist.com hint: To leave the PICList
> > >mailto:piclist-unsubscribe-request@mitvma.mit.edu
> > >
> > >
> > >
> > >
> > >
> >
> > --
> > http://www.piclist.com hint: To leave the PICList
> > mailto:piclist-unsubscribe-request@mitvma.mit.edu
> >
>
> --
> http://www.piclist.com hint: To leave the PICList
> mailto:piclist-unsubscribe-request@mitvma.mit.edu
>

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu