Stuff related to MAV's (and UAV's) from a hobbyist's point of view. Info

Progress on the autopilot

I didn’t do this incredible much on the autopilot since the last post. Flight tests and other work took most of my time. On the code, most of the work went into:

  • Documentation. I used doxygen for the code documentation. Maybe the generated documentation won’t be used a lot, but at least a code documentation standard is set with this decision.
  • Waypoint navigation. I added basic waypoint navigation. Right now the waypoints are still defined in the code, but I plan to store them in the Pic’s EEPROM. This would allow about 30 waypoints. Enough to start with!
  • Refactoring. The code was already nicely structured, but I refactored some parts to make it more readable.

I’m still undecided whether configuration should be saved in EEPROM (and thus changeable at run time), or at compile time (as the paparazzi folks do). On the long term, I guess it’d better be changable at run time…

Flight tests were promising. Sunday I flew my easystar in winds with about the same speed as the easystar at 3/4ths throttle. Stabilization was no problem. However I needed to fly the easystar at full throttle most of the time, which indicated that an altitude hold-feature would be very usefull :-) I’m just afraid that the GPS altitude will never be accurate enough…

Before making any part of the code public, Mariano will help me in further testing and improving the autopilot. I think one of his main interests are the development of a CAN bus architecture for adding other modules to the autopilot. Obviously his tests will probably reveal a lot of bugs/improvements due to his other setup (eg. negative shift for PPM?).

For the moment, I can’t tell when it will be released in public. One of the main reasons for this is that I would like another iteration of the hardware design ├ánd I would like to offer the hardware in a webshop because I believe that the hardware availability is one of the major setbacks of the current open source autopilots.

27 February 2008, 20:31 | Link |