![]() ![]() ![]() That also caused similar issues on return to normal as it abruptlyĬhanged whatever the newly required iTerm value would be.Ģ.8 has code that reduces iTerm accumulation the higher the roll rate, but never arbitrarily cuts it to zero. In 2.7 this was changed to not reset to zero but to hold the value iTerm was at when the threshold was crossed. ThisĬontrolled excessive iTerm gain but caused a small but unwanted step change in pitch at the time of returning back past the threshold. ITerm didn't start accumulating again until gyro rate fell back below the threshold. In 2.6 code was introduced that set iTerm to zero once gyros indicated a certain level of rotation. However in some situations ITerm accumulation is inevitable and the challenge is how best to deal with it. In that sense this is a symptom of P not being quite enough, or I being too much. When dropping throttle, the need for that amount of iTerm changes, and it takes a short time for the iTerm to drop back. Pitching back means that P alone was unable to retain the intended angle in FFF, and iTerm accumulated in an attempt to get there. blackboxes show normal behaviour.Īny slow pitch back type thing is iTerm related. There is seriously nothing with the pitch. I am here talking about P's around 6.510 depending on the quad. I retuned all my quads yesterday and typically only my littlebee quads reaply needed much more pitch P to make the pitch stable. Just raise your pitch P and perhaps lower I. I bet all of the guys who have pitch issues fly with very low pitch P's I thought I would buckle and get some help here first. One thing I haven't tried is swapping components around. Either way, it does seem that one motor is producing more thrust at idle than the others or something like that. I am not well versed enough on how the PID loop reacts to that sort of situation. I noticed that often the quad was tilting forward and to the right when I dropped the throttle so this would make sense that the PID loop would try to reduce the number 3 motor to stop the back left of the quad from lifting but I can't work out why, when that didn't work the FC didn't try raising the other 3 motors a bit to maintain attitude. One thing I found interesting in the log is that if you look at the motor traces at those points, motor 3 is "flatlining" at min throttle, while the other motors are still working. I am not getting any rolls of death or desyncs I don't think. I have also tried calibrating and recalibrating my ESCs with a variety of methods.If you could look at my log and suggest some filtering as a solution I would appreciate it I have tried a little bit of playing with filtering but not a lot.I have tried betaflight 2.7 and 2.8 with the same result.P to the point where I was getting distinct propwash oscillations and I to the point where my flips were starting to feel kinda "sticky" and a constant angular rate was not being maintained with a given stick position I have tried raising P and I for pitch and roll quite high.The motors start running cleanly at 1055, today I had it up as high as 1110, with the same behaviour at zero throttle occurring. I have tried a wide range of min throttle settings.I have definitely made sure airmode is ON.In the log you can see it occurring once at about 4 seconds in (the first throttle drop in the flight) and twice at about 32 seconds ( the first two throttle drops after 32 seconds). The quad just dips and bobs in a direction and when I throttle up again it pitches and or rolls the other way. It varies what actually happens when I drop the throttle but the general idea is that there seems to be a coupling between throttle and pitch, roll and sometimes yaw. ![]() What is happening is the quad is not holding it's attitude at zero throttle. I saw this post on FB thought it might be useful to someone who don't have FB or Google accounts, so i am reposting it here, All credit goes to Kent Boehm ![]()
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