Oscillations induced in the dron by a heavy camera mounted on a big gimbal

[deimerjc (Deimer Caldera)]

Hi guys,

I have a big coaxial copter (28 inches props) and I am experiencing a very funny situation. I have an excellent tune, tested with and without payload (up to 10kg) hundreds of times. We followed the instructions in the wiki to set every parameter… in a few words, I am happy with the tune so don’t think I should blame the tune parameters for the problem I am about to reference here.

There is an specific payload, a heavy camera mounted on a big gimbal (10kg in total), which is having me troubles. It happens that as soon as I lift, I notice a constant oscillations in the system: while the gimbal remains steady in the air, you notice the oscillation/vibration in the dron itself ! It is like the gimbal motors, while trying to maintain the camera steady, are translating the movement to the dron instead to the camera! I can fly like this, as soon as you get some horizontal speed, the problem is less apparent. However, I would like to get rid off of this effect. Has anybody experienced a problem like this? If so… what do you recommend me to do, assuming the tune was done following all the steps documented in the wiki and looks quite good?

Thanks in advance

[xfacta (Shawn)]

Check this thread. Have you tried changing the ATC_ACCEL_x_MAX params to suit the new payload?
It could be something else, but that would be my first guess.

Is it best to AutoTune with or without payload?

Is Autotuning without payload then changing ATC_ACCEL_X_MAX using the below formular for a new payload as good as Autotuning with the new payload? New ATC_ACCEL_P_MAX = ATC_ACCEL_P_MAX x (min_TOW / max_TOW) New ATC_ACCEL_R_MAX = ATC_ACCEL_R_MAX x (min_TOW / max_TOW) New ATC_ACCEL_Y_MAX = ATC_ACCEL_Y_MAX x (min_TOW / max_TOW) ATC_ACCEL_X_MAX seems to relate to prop size so wouldn’t Autotuning the same machine at different weights result in different tuning parameters e.g., PIDs etc?