High Vibrations in Arms

Hello!I just assembled my very first drone, and I’m really excited for the first flight. However, every time I ARM the drone, I notice some vibrations in the arms, when in Stabilized mode (Even Manual). On increasing the throttle, the vibrations become more prominent. These vibrations are present only when I try to balance the drone in its stable position. When I tilt the drone along the sides, it vanishes. I have calibrated the drone a lot of times, but the problem still persists. There is no vibration when I change it to Altitude mode. I am currently using the following components:

FC: Pixhawk 2.4.8
Motors: Emax ECO 2306 (1700kv)
Frame: 5 inch generic Quad frame
ESC: Littlebee 30A

I also don’t have an RC hooked up as I want to achieve completely autonomous flight (I know this is a bad idea, but I’m low on time and resources to purchase one now). I’m using Qgroundcontrol Virtual Joysticks to initiate flights.

I took a log and obtained the following results with default parameters.

I haven’t done any kind of PID tuning (Not sure how to go about it). I have tried smoothing the Actuator Control FFT graph by varying IMU_GYRO cutoff and MC_DTERM cutoff. However, across a wide range, the default ones seem to reduce the vibrations the most.

Would love to solve this problem at the earliest as I have to present this project at an expo.

Thanks a million!

@bkueng you might be able to help here.

@antonyjohne make sure to check this: https://docs.px4.io/master/en/config_mc/pid_tuning_guide_multicopter.html

Indeed! :slight_smile:

You need to do the PID tuning. I don’t see much from the log, but the gains are probably too high. You can try to reduce MC_{ROLL,PITCH,YAW}RATE_K, or change the airframe to ‘Generic 250 Racer’.

Thanks for the reply! Will try out your suggestions and reply. Are you sure you don’t notice anything weird with my Actuator Control FFT graph?

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