ELECINF344/381

Partie interactive du site pédagogique ELECINF344/ELECINF381 de Télécom ParisTech (occurrence 2011).

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Copterix has had a harsh day

Today, we added the yaw servomechanism on the Copterix and it responded pretty well, it is now able to fall slowly like a fall leaf. Sorry we don’t have any video this time, but you will soon understand why…

Our octocopter went through a lot of trouble:

  • When we passed on battery, motors were twice as powerful as on sector, and even though we lowed them a lot, it finally crashed on the ceiling. That was of course not a real test environment (indoor flights are not the exact purpose of a copter), and that is exactly the reason why this accident occurred. It turned out that we just had to change a propeller and our copter was back on tracks.
  • Since yesterday evening, Copterix tends not to start properly. We thought first it was because of the motors card security, which turns off every motors in case of a brutal startup, but it was late tonight we finally discovered with our teacher that it was just a bad contact between a part of this card and the rest of it on the i2c bus, and we finally fixed it.

Afterwards, we performed a Radio Frequency test and it went really well: we think we will be able to control the thrust, roll and pitch by remote control after a few callibration.

Finally, we started our web site ! We plan to add a lot of content about our project during next week, keep on checking !

Copterix: motors control, 1st test

Sensors and effectors

For now, we configured all sensors and effectors:

  • The Sharp, the distance sensor, works in 1-5m range and we get values with 3cm precision
  • Inertial Measurement Unit (gyros, accelerometers and magnetometers return correct values)
  • Radio Frequency (remote control, see video)
  • Motors (see video)

Here is a small video where we directly control motors’ speed with remote control:

Communication

We now have a reliable communication between our PCB and the Gumstix, thanks to Samuel Tardieu’s help.
We mostly use ZeroMQ to share data between our processes and even between our computers !

Kalman

Kalman is quite smoothly, works as well on PC as on Gumstix, and we are now optimizing each operation. The actual filter is fast enough for real-time execution (we spend a lot more time to wait after data than to actually process it), but we want the filter to use less processor working time in order to execute other heavy tasks, like Lucas and Kanade (video tracking algorithm).
We do now have a way to get by Wifi only the Kalman’s results in order to display them on a PC using OpenGL as you could have seen it on our previous videos.

Next step

We are now up to test for the first time real servomechanism PID on our Copterix !