I have a 13 in Mark 4 quadcopter. The cost of the frame is only $40 with 508 kV motors running on 8S and 1308 Gemfan prop. The frame is very poor quality and the stabilizing bar falls part right away due to lack of glue and rigidity. Each arm is held only by two 3 mm screws.
The frame works and the quad is fine. With the default parameter, everything was fine; it could do RTH, etc.
I did an autotune, and Quad is very different. Quad is a lot more responsive, and not so sluggish. But the quad feels very uptight and going on the verg of unstable.
I have a flight log here. Can anyone comment on the tune/ gyro settings, parameters? Is this crash purely due to the pilot error?
Note I didn’t use aggressiveness = 0.1 for Roll Pitch and Yaw. I used 0.05 for Yaw, and 0.07 for Roll and Pitch.
Vibrations really started to climb as the quad accelerated. More than normal especially given how low the vibes are in a hover. Don’t over look some kind of mechanical failure.
You may have too much filtering. I see a FFT filter and ESC filter both in the same frequency range. I can’t check the filtering because the logging isn’t set, but just in general I would say this isn’t needed. You can probably get away with just the ESC filter and turn off the FFT.
In the post crash, one of Quad arm is completely bent out of its regular angle. The crash is into wet soil, and it is soft, so I don’t think the Quad arm bent is caused by the physical impact of hitting the ground. Also, the arm bent is not the two arms with the most motor soil; two front motors had a lot of wet soil, but one of the back arm is stuck bent. I think autotune is much harder on the air frame.
I might set the gyro filter too high ~ 90 Hz.
For FFT and ESC filter, I thought I specifies the minimum frequency. ESC filter will calculate in real time what is the desired frequency, and FFT will calculate the same.
Here is the hover. What is the recommended setting for gyro?
You could maybe dial the filter in a little tighter but this would give you the idea. The second peak at ~190 Hz is still below -50db so there’s not a lot of value in using the processing resources for a harmonic so i left it off. It would probably just add more delay. Overall, a single ESC filter does very well on this.
