Oscillations can be a very broad topic. Generally speaking, you should not experience oscillations with default PIDs. The multirotor frame and props can be a large factor in creating vibrations at different frequencies. These frequencies can get absorbed by the Gyro and thus lead to oscillations. A thinner frame and more flexible props seems to be a large contributor to vibrations. On occasion, you can avoid oscillations coming from a flexible frame\props by using a lower level for the LPF filter, but with this you’ll sacrifice some responsiveness of the craft.
In some cases it helped to use rubber rings or washers on the standoffs or use rubber standoffs to decouple the FC from the frame if you can’t fight the vibrations coming from the Motors/prop/frame otherwise.
There have also been reports that the FrSky Taranis might be the cause for mid throttle oscillations. Read the illustrated tutorial by JimmyRigged, explaining the steps.
Firmware version 2.1.8 of OpenTx might be a solution since it tackles the jitter on the receiver outputs.
YAW P should be the first thing to look at if you still have mid throttle oscillations.
Lower your YAW P values then.
Though similar or even identical setups and motor/prop combinations of other users didn’t show this behaviour, in some cases it helped to set OneShot 125 instead of using OneShot 42
Some users reported oscillations around the throttle midpoint. You could potentially solve this problem by adjusting the TPA settings in the “advanced” section of the KISS FC GUI. By default TPA settings are:
0% throttle = 30% TPA influence
30% throttle = 0% TPA influence
50% throttle = 0% TPA influence
100% throttle = 100% TPA influence
*You can try to raise TPA influences around the 50% throttle (Breakpoint 2). Also, you can try to increase the I term for Pitch, Roll, Yaw by 0.05 at a time.
Additionally, if you experience some low frequency vibrations due to frame resonance at throttle zero, (i.e. during hang time maneuvers) you can try to raise the TPA influence at the Zero Throttle mark.
Here you can find the TPASheet Spreadsheet calculator by kenkamm, works in google documents too.
If you still find no success with testing these values, also test different configurations with the Low Pass Filter setting (see below).
Please note: Prior to testing these values, you should ensure that your flight controller is running the latest stable release.
Note for RC25 users:
The RC25 seems much more sensitive to vibrations.
– You can try a higher LPF, eg: Medium High if you were Off with the previous FW versions.
– You can try to lower I and P from the default PIDs
– Try to use advanced TPA, default is 0-30,30-0,50-0,100-100,
maybe you can try: 0-45,30-0,70-40,100-90