This is my PID parameter.
<define name="THETA_PGAIN" value="500"/> <define name="THETA_DGAIN" value="380"/> <define name="THETA_IGAIN" value="0"/> <define name="THETA_DDGAIN" value="0"/> This is my PID curves:
It is strange, the vibration is not around the set point, it vibrate above the set point, but never exceed the set point,I try to decrease the dgain, and the curve exceed the set point, but vibration become violent.
i can you send a paper from 2006 that noticed the same behaviour of
PD-feedback controllers for muticopters.
We had a similar problem by fitting a small multicopter 200g 100mm
motor distance with paparazzi in 2012.
We had the situation that the system hovers, when vibrations occurs even
the throttle stick where set to zero.
What is the source of vibrations in you system?
1. Not fitting values of the controllers?
2. Unbalanced propellers or motors bells?
3. Sagged motor axes?
4. Weak motor mounting or structure of the multicopter?
5. To weak mounting of the electronic?
For small multicopter i test the situation by holding the multicopter in
Therefore i mount a handle for safety an to protect the electronic in
If i feel vibrations i do not start.
You can find the basic setting by the hand test.
If you give hits in roll or pitch direction with you hand (by holding
the system with you hand) you can monitor the basic stabilization.
If the reaction is to hard you have to decrease the d or and p gain.
I found that with this method good values for the first flight are
found in about five to ten minutes.
The PD control system is able to do the basic stabilization of the
Sometimes it is difficult to find out the source of vibrations.