That all makes sence, thanks Chris.
Tim
Tim,
I havenāt had time to read the discussion but I have Castle creation edge HV 120 in my heli. I am using RSC mode 2. I set my channel 8 switch to start and stop rotors turning I use the set point to tell the esc what speed I want by the PWM. The govenor mode of the esc allows you to set that 3 different RPMs based on the the pwm range it sees. Iāll post my parameters when i get a chance
Bill,
Thatās actually what iām doing right now. Adjusting to mode 2 and setting the parameters.
Tim
Hopefully itās working out ok
So I went ahead and set up the throttle to mode 2, set the PWM to 1400 on throttle out, verified the run-up by watching the status in MP and repeated a few times to make sure it was working as it should. So far so good, iāll have to spool it up with it strapped down and load the collective to see if it can actually govern that low. Then hopefully I can get it airborne with the training gear attached just in case its an oscillating mess.
Bill,
It would be interesting to see what setting you are using on Castle as thatās the esc iām using as well.
Tim
Anything specifically? You are using govenor mode right? The esc will tell you if it canāt run a particular speed based on the gear ratios and set up info you give it. Otherwise Iāve always trusted the esc gave me the rpm requested. Just be sure you give it the correct poles for the motor and the size battery info.
Bill,
So your using āset rpmā and not gov high or gov low? I am currently using gov high as that was the only way I could get the headspeed I wanted and still be governed according to the castle software. I guess I was just interested at what % of output castle was allowing you to govern at in āset rpmā mode if thatās what your using.
Ive never attempted to use that mode for low headspeed work, I do use it on my 3D machines though and never had a problem as they are usually 1910-2100 RPM on a 700 which is 80-85% depending on which machine and the gearing/motor KV I have on it.
Tim
70 to 90 % of the rated capacity of the battery. So we are running 12s so 70% to 90% of 44.4vdc. Then multiply that by your motor kv and then divide by the gear ratio to get head speed
It flew! Like a drunken sailor at first, but flew nonetheless. Got the P gain to .1 before the pack ran out and I got sick of fighting the wind.
Tim
If I donāt have something mixed up, those are the flight logs throughout a few different arms and hovers. I will link video of the flights for analysis a bit later. I was chasing it a bit, there seems to be some bounce on the pitch axis and it was always trying to head to the right so I was constantly correcting? Does this have to do with setting ālevel accelsā in MP?
I also donāt know if the vibes are good or bad? I looked, but I have no idea what constitutes bad or good vibes and if iām even doing it right in the log viewer. I selected the āvibrationsā tab.
Thanks,
Tim
Tim,
Congrats!! I will try to peak at your logs later tonight. Glad you had a successful first flight
Thanks Bill. This was probably the most stressful hover ive done, not knowing what to expect from the unit, but definatly more confident now that i know its not going to flip itself or dart off in some weird direction. Pheeeewww. Lol
And thanks for taking a look, definatly appreciated.
Tim
Tim, I looked at the logs with the pitch bobbing phenomenon. Lot of variation between desired and actual pitch, which is to be expected with soft rate PIDās. But looking at the RC out, to see if the elevator servo is actually driving the tail bob indicates itās not. Classic indication of headspeed being too low.
Most Align helicopters wonāt fly very well with blade tip speed much below 425 ft/sec with a two-blade rotor, which is 1,450 rpm for your 800 stretch.
Chris, it was nothing too crazy, kind of chaulked it up to everything being a shot in the dark, or just no-where near tuned. Unless i hook up a phase sensor, or castle live link, ill have to tach it to see exactly where the headspeed is. Its down there thats for sure, first attempt after swapping over to the method you gave me for throttle. Definatly bringing it up a little. Ill post a video once i transcode it, came out over a GB so pretty hard to share a file that big through google drive.
My biggest worry at this point is, where to start the I gain once the P gain is maxed out and are my vibes im check where i have the unit mounted?
Tim
Tim,
I looked at your logs. Looked like only one had the flight. I couldnāt tell what you were doing on the others. Keep driving the P gains up in pitch and roll until you reach 0.2 or so. Or until you hit an uncommanded oscillation. As you bring it up past 0.15 you can probably start backing off on the VFF gain. After you get the P gain set, then start working on the I gain. Once you bring up the I gain it should start holding attitude a lot better. There is little concern for bad oscillations with the I gain so you can put it to 0.1 and see what thatās like then 0.2. I think as long as you keep the ILMI parameters at 0 then you should NOT have a problem with weird attitudes on takeoff.
Tim, the vibes looked pretty good. Some aliasing of the IMUās on the X axis but nothing bad enough to set off EKF lane changing. Itās definitely ok to fly so once you get the headspeed youāre going to run dialed in and get it tuned so itās flyable, then can take a closer look at that. Sometimes all it takes is to turn up or down the headspeed and it totally changes the vibration characteristics.