Flammert

Imatfaal: No we don't. Basicly how we balance the quadcopter now is: We have the input from the gyro in rad/s, we integrate that value so we get the current angle, then based on the speed that we are rotating in and the current angle we adjust the speed of the propellers. So we aren't doing any aeronautic tricks. But its the first time I have heard of it, it looks very interesting. Mordred: One of the goals of the project is to learn to build a PID system. Our current PID is pretty good, it is quite stable and it has just a little overshoot. The only problem that we have is the drift of the gyro, and a (I guess) mathematical problem (witch is kinda hard to explain). The mathmatical problem: If you take your phone for example, rotate it 180 degrees of the, x, y, z axis. Now you phone is in the same position as where it started in, but the values of x, y, z are all 180. So in case of the quadcopter, the arduino would think, that the angle is incorrect, but the quadcopter actually is in the right position, so the arduino will correct the quadcopter wrong. I hope I explained that correct and clear.

My project mate is the expert on that subject, I will ask him to write a little about it. But in short what we do is, we look at the current angle and the rotation speed. If you only look at the current angle, then if you just corrected the angle to a 0 degree tilt, it still has speed so it overshoots to a -10 degree tilt. So basically what you do is when you get close to the 0 degree tilt, you correct the rotating speed.

I maybe, going to add FPV to it. But if I would do anything with a camera, I would use a separate system. So the 'quadcopter calculations' run on a realtime system and the camera on a raspberry or something.

For the sake of simplicity we (I forgot to mention im doing this project with a friend) are using an arduino for now, but we are considering to use a stm32f3 /stm32f4 discovery board. Because it has so much more capacity (much faster, floating point unit, etc.)

That is an much simpler answer then I was expecting, I have been breaking my head over this for a long time. Thanks!

I have a project to make a quadcopter fly autonomous. I use a 9 degrees of freedom pcb, wich has a gyro, acceleration meter and compass in it. We are now flying with only the gyro. A gyro however has a few imperfections like drift (and a imperfection I dont know how to call). So a you cannot fly on a gyro alone, so when I search for some answers to that problem I find solutions like the complementary and kalman filters. They combine the data from the gyro and acceleration meter. But how can I use a acceleration meter on a flying object? The acceleration meter can only measure the force on the quadcopter, and the force on the quadcopter is the force generated by the propellers it self, (which is always on the Z-axis)? A prove for this is that if you place a glass of water on a quadcopter, the glass would always stay on the quadcopter because the only force on the quadcopter is in the z-axis https://www.youtube.com/watch?v=w2itwFJCgFQ#t=275 Flammert