I just got another bum e011. Already burnt another motor. That's 2 e011's that each burnt a motor in the first 48 hours. Mine has so much vibration that my whole camera view is total jello, my ducts look like wet noodles flopping around on screen .... no way this thing can handle the reduced filtering of my high performance software setup. It requires a clean vibration free setup. So far i am throwing everything at it but the kitchen sink to tune it. Obviously quality control is not china's strong suit. I'm not upset about it ... As we are going to need an alternative setup for the ones that don't run perfectly smooth and there is no way I'd be able to guess without a super crappy one in hand. If I can tune this thing in such horrible shape ... I should be able to tune anything. Lol. I tried 4 sets of props with no improvement and no motor shafts are bent ... it's just internal to the motors I guess.
What kills me is that there are probably a dozen people running my high performance software setup with no problems ... and I get an e011 in the mail that tries to fly away on my file AND also burns a motor before day 2.
For those of you that get into the science of this stuff ... it comes down to latency in filtering. A whoop requires an insanely high p gain to have the strength to keep the craft perfectly on course in wind, propwash, or at full throttle or aggressive piloting. It's really a terrible design for a craft. In order to crank P to these unreasonable limits - latency has to be reduced or the action that P takes is just late enough to the party to cause constant uncorrectable oscillation. So filtering takes 10 times longer than the loop at defaults - no problem - filter less and reduce latency. My last tune cut this delay in half. On a smooth running craft that's no problem. So the problem starts with vibrations and the d term. The d term is active when things are changing rapidly. Like ending a flip - you go from spinning fast to not. Thats the kind of rapid change that we want D to go active on. Unfortunately noise from vibration is all over the place too - a rapidly changing signal coming from the gyro. This makes the d term go nuts and start pushing on the craft when it's not supposed to - or rather when we don't want it to. So my challenge is to find the right filter or combination of filters that reduce enough latency so i can get p high enough to have the strength to force tight and accurate corrections in flight while still giving me a clean enough gyro signal to tune D up to balance it out so everything looks smooth. Previously I had turned software filtering off and just relied on the hardware filtering ... that would not work in my tests today. Then I tried combinations of hardware and software filtering - got close but still not good enough. On a long shot I decided to try turning hardware filtering off and only do software filtering. I think I may have nailed it with that. There are lots of software filters to choose from and some of them filter twice or 4 times (2nd and 4th order filters). It looks Like a 2nd order filter at around 40 hz may just do it. Was flying today with smooth control at full throttle in windy conditions and had P gain all the way up to 26.5 - previous tune was 19.5. I still have a little mid throttle oscillation to chase out but I have not started raining D yet and may be able to turn P back down some. Cross your fingers I can create a locked in tune for a shakey e011!!!!! I'm afraid we are going to need it sooner or later. Hopefully some ripping flight video will come out of my tuning session tonight!