[Xenomai-help] Advice for a newbie on Xenomai & USB

[David <correupeldavid@domain.hid>]

Hello,
 
I am a PhD student at the Technical University of Catalonia. I work on 
UAV helicopters. It is a new field in my research group so I need to 
develop the rig before start working on Identification and Control 
Theory (which is supposed to be THE topic of the Thesis).  
 
We chose to use en embedded PC as 'brain'. The readings of the system 
come from an IMU and the actuators (R/C servos) are commanded by a 
microcontroller (already programmed and working). Both devices Tx/Rx 
input/output data with the computer through TTL USART converted to USB.
 
The PC is an Intel Atom Z520, on a chipset ..., with 1GB of RAM and 
booting on a high-speed Compact Flash.
 
On the first stage of the software, a human is choosing the 
microcontroller inputs (that is: piloting the craft), and the computer 
'only' needs to gather the input to the microcontroller and the output 
from the IMU and write it to disk with due time stamps. 10Hz would be 
OK, 100Hz would be the goal.
 
On the second stage, the computer will have to gather the output data, 
compute the control input and send it to the microcontroller. On hard 
real time at (>10 to 100) Hz, of course.
 
As you may guess, I chose Xenomai to make sure time requirements are 
respected. It would run on a command-line Ubuntu 9.04. The programming 
would be developed for C++ (compiled with g++).
 
As a totally newbie on Xenomai and only average user on Ubuntu-Linux, I 
would need some community guidance to get my feet wet.
 
As you already know my specifications, do you think the computing system 
is suited for the needs? As the computer does not have embedded USART 
modules, I rely on USB to TTL USART converters (ttyUSBx). Are there any 
suitable drivers for Xenomai? USB4RT? With interruptions and 
configuration for SSP?  
Where do you guess the bottlenecks will be?
Is there any detailed guide for newbies? Could you suggest me any 
documentation on PC architecture and/or Linux OS to fully understand the 
system? I have mainly programmed microcontrollers, on which I would make 
use of interruptions and input/output modules all the time, and I need 
to port it to PC, for which I have never used interruptions nor used the 
input/output modules' drivers deeply nor write them.
 
Any suggestions would be very useful.
 
Thanks for your help.
 
Best regards,
 
David Lavèrnia