Micro tuning techniques - different than larger quads


#121

whatever is most convenient for you. I can make changes a little bit at a time, or all at once. I may only be able to test flight in the mornings before work though. wednesday and thursday I can test more frequently, ill be off.

edit: i may be able to make small test flights inside at work too though, to check for oscillations etc, but for real world (Windy) test flights i can only do those in the mornings until wednesday and thursday


#122

Ok, I will come up with some new “default” pids for you to load tonight along with a few other settings to change. You can test that, report back, and we will go from there. What’s your all up weight?


#123

Sounds good. The crook weighs 41.5g without battery.


#124

You use about a 500mah?


#125

I’ve been using a 19g turnigy nanotech 750mah , for a total weight of 60.5g


#126

OK @quadlifepro - here you go! Before we go much further though - what have you set your gyro and pid looptimes to? Do you ever fly in angle?

set use_unsynced_pwm = ON
set motor_pwm_rate = 8000
set gyro_notch1_hz = 0
set gyro_notch2_hz = 0
set d_lowpass_type = PT1
set anti_gravity_gain = 1.5
set d_setpoint_weight = 85
set p_pitch = 90
set i_pitch = 55
set d_pitch = 102
set p_roll = 85
set i_roll = 55
set d_roll = 98
set p_yaw = 110
set i_yaw = 65

Paste all that into the cli - hit enter - type save - hit enter - and see if it hovers. Be ready with a disarm switch cause I turned alot of your filtering off and it may just want to fly away. If thats the case, paste the following in and save it.
This should fix the fly away.
set gyro_notch1_hz = 400
set gyro_notch2_hz = 200

If it doesnt, then save this on the cli:
set d_lowpass_type = BIQUAD

Then go fly - I feel these values on the aggressive side of what I would consider default values for a 8.5mm brushed micro with fast motors. Report back what it does and how it feels and we can go from there in session 2.

Flying Procedure
***Cruise around at high altitude, in wind, or in bumpy air. Look from any large bobbles and pay attention to what axis they are on. Then do some slow flat decents with a small bit of forward speed and look for the same thing. Finally, go slam into some sharp 180’s and check what our baseline propwash condition is - this will improve as we tune - but its nice to have a frame of reference for where you started.

Our plan is to raise P gain on roll and pitch until all bobbles and bumps from external influences like wind, bumpy air, or possibly some propwash turn into tight high frequency oscillations. Then we will raise D gain until you can just hear those oscillations but cannot see them on FPV. I lowered your setpoint weighting to where I think a powerful quad takes stick input smoothly. Once we tune it for fluid flight - we can crank that back up for a snappier racer type feel if you want to. This value is sort of a freestyle feel but is a good place to start exploring. After locking in the tune, we can also raise setpoint transition which will go further towards the racer feel and make it dig in sharper if you feel like its too much “on ice” sliding around. But we need that low right now just in case my default tune is a little off - that will help compensate.

Let me know if you have any questions.


#127

@tronaton, I just want to check in on you as you were exploring this method too. Have you had a chance to go test yet? Do you have any results/problems/successes to report?


#128

Yup…paying keen attention to this thread. I’ve hated flying in the wind…looks like it is time to change that! I’m still going to go nuts with my Chameleon build for GoPro goodness, but to have a micro feel as locked in as this thread suggests…YES PLEASE.


#129

My 100mm 8.5 build on an f1 scisky is flying equally as good as anything I’ve ever owned and feels /looks the same under fpv in any conditions. It’s not a fancy f 3 flight controller, it’s got mismatched generic motors, but I’d put it up against anything in the sky - it’s butter smooth and rock solid! Try the process … it works! And it’s simple and easy!


#130

I’ve found that the default values for I are low in BF 3.1.7. Maybe they are “high enough” (freestyle guys usually run lower I) but I find that I prefer the feel of a quad with much higher I values. The result is a more “locked in” feel, it tracks better, holds attitude better in a carving turn… flies more like a sim. Too much I can lead to some weirdness, but I haven’t noticed it yet at the levels I run.

My values for I:
(roll/pitch/yaw): 90/100/110

Helpfully, I is largely independent of P,D so you can try different values and see what you like. I picked the numbers above for a first try… felt great and I’ve just stuck with them. I suspect you could go still higher without weirdness.

This, combined with making the filter changes, cranking up P and D has resulted in something that feels like Raceflight (which is a huge compliment.)

Edit: I crank up I in Raceflight too compared to defaults. Again, it’s a feel thing. Do whatcha like.


#131

It must be something wrong with the accelerometer. Nothing I do will effect the slide/slow level return.
It is in rate mode.

I will only fly my aliens los now.
Still looking for a good affordable brushed fc with buzzer.
The eachine f3 is screwing up in the satalite department. So far I’ve had 3 boards loose power or sat communication. My friend had his work fine until the other day…
He lost sat communication as well.

I’m only able to fly my sci-sky v1 currently.

My 110 brushless fc eventually toasted out on 3s.
Awaiting more fc that are rated 4s. To run 3s safely.


#132

@NotFastEnuf I tested out the tune…

1st battery it flew really sharp in terms of stick response, like amazingly perfect. Inside I hovered and tested flips… flips were perfect, I was so excited… 4:00 of flying inside I landed, and motors were HOT… kind of alarming but I tried to keep my cool and follow through with your instructions.

2nd battery I plugged in and I noticed throttle response was extremely sluggish, and sometimes it would kind of drift away a little so I decided to add back in the 2 notch filters you suggested for step 2. I plugged in and went for a test flight inside and it had complete throttle response back…

3rd battery, I tested indoors and made sure everything was cool before going outside. 2 minutes into flying inside, I took it outside flew it in fairly windy conditions, pockets of air being swished everywhere…

I went outside and flew the remaining juice left of the 3rd battery. I squeezed all 4 minutes of flight time out of my timer on the TX for that battery…

I was shocked bro. Freaking SHOCKED at how much of an improvement your tune made for the crook…
I TRIED to create propwash and couldn’t. It flew SO smooth, and like it was TOTALLY locked on rails… flips and rolls were beautiful, punching out was awesome… I could not notice any wind which honestly was kind of tripping me out. Like I have never flown a brushed quad that wasn’t affected by wind…

The motors sounded different, almost like I could hear them all completely working independantly upon each blast of wind that hit it…

This was not placebo effect, you are simply the Tuning Master.


#133

also, i forgot to mention, i barely ever fly in angle (only when showing off to my non-quad friends who don’t understand the difficulty of acro mode… no point in stressing when u can just impress them in angle mode lol )

about the gyro, and looptime - I will try to see if i can find what it is set to…

So that was just atest flight outside, i will continue with part 3 2moro morning, the Flying Procedure and I will report back the results…

(Thank you so much for looking into this for me and helping me out with this… tuning is certainly a weak spot for me, and I’m so excited and happy about the results so far though…)


#134

That’s great news. Remember this is just a starting point and it gets even better from here. I think the best thing to do is enjoy it as is for a bit and really get familiar with it again. Be critical, find a situation or behavior that it doesn’t like … post videos, and we will talk about it and push it further from these “defaults” and closer to a custom tune!! Good decision with the filters. Either too much noise was getting in without them or you are close to burning a motor (Unrelated To The tune). If that comes back you may have a bad motor. Anyway, well done and thanks for being open minded to trying something new.

I know you like to rip, but take some time every so often to just cruise for a bit and look for those bobbles from external Influences. If you see any, try to figure out which axis they are on.

In the mean time:
if you want an even sharper stick response- start moving setpoint weight up from .85 towards 2. Move it .15 at a time. That is a big but reasonable chunk that will feel noticeably different.
If you want the craft to slide less and dig in and cut more - move setpoint transition up towards .35 from .2. Move this .02 at a time. That’s a pretty big chunk as well.

I personally prefer my 8.5 with the setup I had you load but prefer a whoop on higher setpoint weight and transition. Reason: my whoop needs to be a race machine to keep me off the walls and deal with tight spaces and obstacles. What I see reminds me of how the videos look from actual fpv races. My 8.5 is flown outdoors and while I like to go fast … There is more room for a more fluid setup that looks more like the freestyle videos posted by 5in quad flyers. It’s all personal preferences.


#135

@NotFastEnuf Yaw shakes in the wind, where should I start? To be fair to the quad/tune, it’s pretty messy air and a heavier quad for the motor than is optimal. Pitch/roll is solid as a rock. Current PID settings (after a hasty windy tuning session) are:
Pitch/Roll: 156 P, 20 I, 200 D (as far as the in-flight tuning will go, it seems). These numbers are subject to change, but seem to fly pretty well. I’ve no real idea what to do with I or what it does in a flying sense. I should probably re-read everything here.

Yaw: 70P, 37 I. Why no D on yaw, anyway?

Going to send it back up with the TX adjusting yaw P/I as soon as there’s a charged battery to do so.


#136

Yaw d is there - it’s just hidden. You can see it in a dump. There are some really funny behaviors in extreme situations where accumulated error in one axis, if not addressed, can transfer itself into a behavior problem on another if they aren’t corrected - or rather that an axis unrelated to the axis with the problem tries to correct the bleed over of the undesired behavior. The air today may have just been that situation. Up your roll and pitch I gain to 55 and see if that helps. If it doesn’t, consider dropping roll and pitch P and D (with i at 55) and then trying to tune up again. If raising I helps - consider that fresh tune up again anyway because you may have over cranked P gain trying to compensate for low I. In other words, some of the burden you were putting on P to tighten up the bumpy ride may have been unburdened by a stronger I gain. Remember that with forward pitch yaw and roll are coupled … for lack of a better word … they both sort of accomplish the same thing at certain times. This is what sort of links the yaw axis to pitch and roll problems. I think I gain will fix it on pitch and roll.


#137

Consider pitched forward flight with I gain too weak to suggest a correction of error accumulating on the pitch axis. You then yaw 90 degrees … This error now belongs to the roll axis at the end of the yaw. But it is transfered into and then back out of the yaw axis through the manuver. Yaw may try to correct it… chaos issues … mysterious problem presents. The three axis can barely do their own jobs independently with a perfect tune … let alone work together if forced to while somebody slacks.


#138

Will do, thanks!

Found yaw-d, it’s not the magic answer. The magic answer may be props (as discussed in chat).


#139

i am getting closer on my brushed tune yet i can’t seem to eliminate a slower bounce back after tight flips and rolls.
any ideas on what i should do?
thank you


#140

Where is your setpoint transition now? Assuming your pids are tuned tightly, this would be the adjustment to control bounce back. The lower this is, the more betaflight will decelerate your roll close to stick center helping to control bounce back.

I have found if you have to go super low - then it’s an indication your tune is not tight. (Could also happen with too tight - but that’s hard to achieve in a brushed quad - we’re talking high triple digit pids)