Large quadcopter with height radar not holding height at stopping or accelerating


I´m having trouble adjusting height PID for 25Kg quadcopter with height radar. I had this problem slighter with V4.0.7 and now with V4.1.5 it got severe. After flying straight forward in Loiter and performing a stop, the copter loses about 1m to 1.5m (also happens when I accelerate). This is probably a relation between Rangefinder and barometric height information fusion. In version 4.0.x there was RNGFND_GAIN and in version 4.1.X there is RNGFND_FILT. Is this just a name change or also a function change since the behavior with the same numbers is different (I use 0.8)? Any suggestions in the PSC_ parameter class tunning?

Flight log with height problems when stopping or accelerating.

It looks like your barometer is affected when you change directions and altitude (more than it should be). See if you can shield it better from propwash.

Thanks Shawn, but I don´t think it is propwash since the cube is well protected inside the frame body. Seems much more a tuninng issue.

Did you try changing EK3_SRC1_POSZ, 2 (RangeFinder) ?
And try doing similar maneuvers within the rangefinder’s maximum range, so we can rule out any unusual pressure variation issues in the barometer
Make sure to fly over a relatively flat ground for better comparison