[chbot] UAV I'm in

[Michael Hope]

I realised after sending that I've chosen the ARM for the sample
reasons you chose the AVR - being quite happy with a toolchain and not
wanting to learn another one.

I have a analogue gyro which I think will be able to make use of the 12 bit ADC.

-- Michael

2009/8/26 Charles Manning <manningc2 at actrix.gen.nz>:
> I too was thinking about the "middle path" using an ARM level micro. That's
> definitely going to get you out of any problems wrt grunt for a control loop.
>
> Since ArduPilot doesn't need much CPU I think an AVR is enough.
>
> Unless you're making multi-layer boards I doubt there's a real benefit in
> 12bit ADCs over 10 or even 8.
>
> In some ways I'm cheating in my design because I'm using a high dihedral
> glider wing that is inherently stable and does not have ailerons and does not
> need roll control. That should severely reduce the need for complex control
> too. The only potentially instability should be pitch (ie. putting the plane
> into an uncontrolled dive or stall) and I'm hoping that a 3D accelerometer
> will be enough to figure that all out.
>
> As my first go, I'll be only using accelerometers, no gyro, which should mean
> that  uncle Kalman can stay at home. In theory you can use two or three
> accelerometers placed at different parts of the plane instead of having a
> gyro but I'm hoping I don't have to go that far.
>
> What will be good is to see what different approaches yield.
>
> -- CHarles
>
>
>
>
> On Tuesday 25 August 2009 19:23:19 Michael Hope wrote:
>> Hmm.  I'm thinking about going pretty much the opposite way - a
>> Rustler UGV with a Nokia N800 running Python and the I/O provided by a
>> ET-STM32 Stamp :)
>>
>> A great thing about the Arduino is that you only need a ATMEGA and a
>> serial port and that's about it.  The ET-STM32 is getting close to
>> that but with the advantage of 12 bit ADCs and a bunch of UARTs.
>>
>> The interesting part will be doing the control loop well enough to run
>> the truck at full speed.
>>
>> http://www.traxxas.com/products/electric/rustler3705/trx_rustler3705.htm
>> http://en.wikipedia.org/wiki/Nokia_N800
>> http://www.futurlec.com/ET-STM32_Stamp.shtml
>>
>> -- Michael
>>
>> 2009/8/25 Charles Manning <manningc2 at actrix.gen.nz>:
>> > I think it would be different to try different approaches and share
>> > ideas.
>> >
>> > The UAV stuff I'm doing is not Propeller based. While Propeller seems to
>> > have some admirable properties for some purposes, I just can't be
>> > bothered learning yet another architecture, getting yet another set of
>> > tools, etc etc. unless there is a very pressing reason to do so.
>> >
>> > You don't need much CPU grunt to do a basic UAV and I'm going to use an
>> > AVR at first because I know the toolchain, they're very cheap and very
>> > easy to use.
>> >
>> > Most control stuff is quite light in its CPU requirements and a 68HC11
>> > (remember them?) is enough to do a two-wheel balancing robot so I figure
>> > it is enough to control a UAV flight.
>> >
>> > If I get to needing something more grunty than that, for some serious
>> > software engineering, then I'd probably put in an ARM Linux board. I've
>> > recently been working with OMAP based Gumstix which will give you a very
>> > powerful Linux board (including 256MB flash and 2456MB ram) in less than
>> > 20 grams.
>> >
>> > I know you could kick of with Ardupilot or similar which will give a
>> > whole drop-in autopilot for approx USD150 including GPS
>> > (http://diydrones.com/), but I'm interested in doing a fresh project
>> > rather than just plugging in an existing project.
>>
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