25 Sep 2002 hudson   » (Master)

IT ACTUALLY WORKS! This weekend, Aaron Kahn and I flew the Rev 2.2 board on my Concept 60 helicopter. Unlike the past few weekends of sensor calibration and data collection, we turned on the autopilot software and it actually flew the helicopter.

The first day we spent tuning the control loops to remove oscillation in the pitch axis and slowly expanded the control authority that the software had. We destroyed a CF 802.11 card due to vibration and had to stop for the day. But it flew!

The second day we came back with new software that I wrote the night before. This allowed Aaron to give attitude commands to the autopilot rather than flight commands to the servos. The standard helicopter is flown by directly commanding the cyclic and collective (and throttle and anti-torque and ...). If you hold forward cyclic, the helicopter will nose over and do a loop or two before crashing.

With our software and hardware, he was able to instead provide attitude commands with his joystick. If he holds the stick full forward, it instead commanded the software to maintain 8 degrees nose down. If he released the stick, it would level out. Suddenly, it became a very flyable aircraft, rather than an unimaginable nightmare to fly.

Next weekend we'll have the compass and GPS hooked up, which should provide even better control. The GPS aided INS won't be running, but we will have a working heading hold.

I've curated flight data from Sunday and we have movies, too:

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