LibrePilot Forum
General Category => General Discussion => Topic started by: Brugghh on April 09, 2017, 10:40:26 pm
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Hey, recently my quad had just started to oscillate a little bit when i'm descending. I posted a pic of my current pids, what would i need to change about to maybe stop the oscillation?
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Do you have these oscillations if you descent non vertically? Often they are caused by flying trough the props turbulences.
Udo
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If your copter has a narrow range of optimal PIDs it may oscillate when descending (low throttle) or asscending (high throttle). There is option TPS (throttle PID scaling) which I use on my bigger copter 450mm.
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As mentioned, TPS definitely helps this. You get to decide how much to increase the PIDs at lower throttle. Another thing that helps a lot if you have a Revo class FC is to run AutoTune.
This is a problem even for full sized helicopters. You get in your own turbulent downwash when you drop straight down in a certain speed range. Come down slower (or faster :) ) or come down at an angle (say 45 degrees).
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Like @theOtherCliff said, this happens to bigger quadcopters and tbh, it happens to any quadcopter even to the Top-notch or the best racing 250 quads with insanely high Pid Loops and Gyro frequencies plus best hardware.