[Paparazzi-devel] Cam4 initial testing report

[antoine . drouin]

Hi everybody

We have mounted the Paparazzi autopilot in the Cam4,
a quadrirotors helicopter build at Supaero.
We have used this bench to run initial testing.
http://www.nongnu.org/paparazzi/images/cam4_bench.jpg

We were able to make it hold an attitude on one axe (P controller on infrared
only). We witnessed worrying oscillations under big disturbance conditions
(when I would hit it strong or realease it at 45 degres).

I think we should try to measure and calibrate the response curve
of the motor controllers.
It would probably help to have a rpm feedback.

Anybody's got an idea on how to do a quick quad-tacho ?
The motors are brushless, so I think that sensing the voltage on one
motor wire could be a solution

I don't have enough comparator/counter on the mega128 do to that here.
Maybe one (four???) external frequency to voltage converter - or a
microcontroller-based solution connected by SPI ?

I really hope that we will not discover that these controllers are to slow.
I think we will have problem with starting time too.

I'd appreciate any comment/idea.

Antoine