Please help with shakey QAV250

[Paul Rosas]

Hey guys I have been flying multirotors for about a year now and have had pretty good success with building and flying them, untill the QAV.

What I have:

QAV G10 frame
Lumenier 2208-9 2000kv motors
Lumenier mini 20amp esc's
Flip 32
TBS PNP Core Pro
TBS 500mw tx
Lumenier arm extensions with 10% tilt
60/45 Gemfan props

I have been ripping around in my little EMAX250 full throttle and thought it was time to step it up a notch so I bought this QAV on steroids. The build went way smoother than I could have imagined, untill I put on props. I understand that props need balanced and will calm vibration but this is not that......Once I take off the quad immediately starts shaking like crazy. Once in the air I cant go over 30% throttle or the vibration get to be to much, is this PID issues? I have been looking into PID tuning and my vibration issue looks to be to shaky for a P issue let alone the rest....correct me if I'm wrong tho anyone. I dont know much into PID tuning and have gotten lucky just having the be able to fly of default tuning with some adjustments to roll, pitch and yaw so I can flip and roll faster.

Also when trying to throttle down to land having motors that start and stop at different times feels like the quad starts to fall out of the sky but will catch itself.

I would lean towards the side of that my esc's need to be calibrated but the Lumenier mini 20 amp esc's arent aren't supposed to be calibrated, they are supposed to be pre setup when you get them. So my question is why would I have such tight pretty violent shaking going on, it does if from take off till it lands. Brain is fried trying to figure this one out....

Thanks in advance!

 

[Bartman]

do the motors spool up smoothly when you use a receiver to do each one individually? could be gains in the FC making the motors crazy, could be a timing issue, could be a harmonic making the frame shake.

to test for a harmonic, see if the vibrations smooth out after you get past that 30% point, if it's only in a small RPM band then it might be a mechanical harmonic but test each motor individually with a receiver to see how they do first.

 

[Motopreserve]

Hey Paul,

Welcome to Multirotorforums.com! Sounds like you may have a couple things going on.

First, what radio are you using? Also, was this FC purchased from ReadytoflyQuads? Which GUI have you chosen to interface with the computer? Have you checked to see if there are firmware updates?

Probably already done, and I'm not sure you'd even be able to lift off if they were incorrect - but make sure your motors/props are all on the right direction. These FCs use a motor configuration unlike any other I've ever seen.

One test that would be informative is to remove the props, fire it up on the bench and see how the motors react at all levels of throttle stick. See if the cutting out you describe (while landing) happens on the bench.

It's been a while for me - but I recall vividly how PID tuning can be a little finicky. . But get us some more info and I'm sure we can help you get it up and running smooth.

 

[Paul Rosas]

do the motors spool up smoothly when you use a receiver to do each one individually? could be gains in the FC making the motors crazy, could be a timing issue, could be a harmonic making the frame shake.

to test for a harmonic, see if the vibrations smooth out after you get past that 30% point, if it's only in a small RPM band then it might be a mechanical harmonic but test each motor individually with a receiver to see how they do first.

Hey Bartman, when I go past 30% the shakyness just gets worse and when I give just enough throttle to spin the motors only a motor or two will spin up and the other two wont spin up till more throttle is given.

 

[Paul Rosas]

Hey Paul,

Welcome to Multirotorforums.com! Sounds like you may have a couple things going on.

First, what radio are you using? Also, was this FC purchased from ReadytoflyQuads? Which GUI have you chosen to interface with the computer? Have you checked to see if there are firmware updates?

Probably already done, and I'm not sure you'd even be able to lift off if they were incorrect - but make sure your motors/props are all on the right direction. These FCs use a motor configuration unlike any other I've ever seen.

One test that would be informative is to remove the props, fire it up on the bench and see how the motors react at all levels of throttle stick. See if the cutting out you describe (while landing) happens on the bench.

It's been a while for me - but I recall vividly how PID tuning can be a little finicky. . But get us some more info and I'm sure we can help you get it up and running smooth.

Hey Motopreserve, I am using the Taranis x9d radio and my FC (Flip 32) was purchased from massive rc. I am using CleanFlight and I flashed with the most current stable firmware.

All props are on right and the quad will get in the air and fly but only at super low throttle any more throttle and the shakes get bad, she's a little floaty in the air and I believe that can be tuned out, but the shakes seem like something else.

When the quad is sitting on the bench and I give her throttle everything spins nicely and throttles just fine, but if you watch from cleanflight the rpm of the motors are off sync but if I use the pot switches thru cleanflight and not the Taranis radio then everything is in perfect sync. Tends to lead me that the sync of the motors are off but Lumenier says not to sync...?

I have beliefs that its all PID tuning but if my P is to high or Low would it shake that bad? Its pretty bad shakiness if I was to try and throttle it, it would get way to unstable. I saw a video on using cleanflight where the guy de-activates all auxiliary channels...arm, horizon..exc... then go into adjustments and sets switches so he can adjust PID's on the spot while flying. I tried this and PID's can be tuned this way but my quad wont start up so I can get it in the air....Is this because there is no arm now since everything was turned off in aux channels? I tried to add an arm channel but quad still wont fire up....

Thank guys for the help!

 

[Paul Rosas]

also guys just a thought....I know that no calibration is needed here but why do they say its not recommended? I have been reading about looptimes and wonder if this needs to be set? If I could just get rid of the shakes all would be sweet!!!

 

[Motopreserve]

Couple more quick questions:

Have you done the stick cal in the Taranis? What flight mode are you in while testing in the air? Also, when you see issues at 30%, are you hovering at 30%???

When you say throttle/motors works ok on the bench, does this mean you don't see the motors start at different times like you do when in flight? When you do this test (bench or air) - make sure you are in ACRO mode (or mode without any type of assistance from the sensors).

The PID being too high definitely can cause shaking - but the fact that the motors are spinning up at different times is a big issue - and no sense in moving on before that is fixed.

 

[Paul Rosas]

Couple more quick questions:

Have you done the stick cal in the Taranis? What flight mode are you in while testing in the air? Also, when you see issues at 30%, are you hovering at 30%???

When you say throttle/motors works ok on the bench, does this mean you don't see the motors start at different times like you do when in flight? When you do this test (bench or air) - make sure you are in ACRO mode (or mode without any type of assistance from the sensors).

The PID being too high definitely can cause shaking - but the fact that the motors are spinning up at different times is a big issue - and no sense in moving on before that is fixed.

when I give it throttle while plugged in on the bench everything works perfectly when I test the motors, its when I use the Taranis radio to do the throttle and not the little manual switch on cleanflight. I am in acro mode so no assistance from the FC...I hate angle and horizon modes...lol....30% throttle i am about 15 to 20ft in the air and shes stable pretty much and flyable but only at that 30% because anything more and the vibrations are almost to bad to deal with. The motors are all good when Taranis isn't in the mix but once I try to use my radio is when it seems that sync in the motors goes away, also it seems as if the FC is still in horizon or something because if I pick up the quad and start moving her around shes constantly trying to make corrections..or is this still normal for acro?

I really appreciate your help thx!

 

[crayfellow]

Hi Paul,
Sorry if I'm repeating one of the experts above but I don't have time to read the whole thread. I can say I had a similar experience with a Blackout flying cc3d when I had the ESC update frequency set wrong (to the lowest setting, 50Hz I think?). Check to see what you have it set to, and if it is lower than the max, try setting it to the max as you've got some nice ESC's.

It behaved just as you describe; fine on the bench then oddly wobbly in flight.

I'll more carefully read the thread later when I have more time

 

[Motopreserve]

Couple things....

Definitely do the stick cal in the Taranis. This makes sure that the sticks are all calibrated and working correctly. Secondly, if you are hovering at 30%, you are way overpowered. You might need to look into balancing the power to weight ratio with some different props???

Make sure you are in "Rate" mode - this is the Naza/Flip32 version of Acro (sounds like you are in this mode in settings, but not in flight characteristics. Make sure when you select the flight mode, it's being saved to the board.

I would try the test with t he motors on the bench - but using the Taranis.

 

[tstrike]

Have you ever been in a canoe with 3 other people all trying to paddle at a different pace?

Calibrate your esc's to your transmitter. If nothing else, it takes that out of the equation. Only takes a few minutes.

 

[Motopreserve]

Have you ever been in a canoe with 3 other people all trying to paddle at a different pace?

Calibrate your esc's to your transmitter. If nothing else, it takes that out of the equation. Only takes a few minutes.

It really does seem that the ESC is a major part of the issue, but I think since the ESC manufacturer specifically recommends NOT to calibrate, might be worth ruling everything else out.

 

[tstrike]

Calibrating links the esc with the particular transmitter has you know. Those must be some smart esc's ...

 

[tstrike]

or at least make sure your transmitters throttle endpoints jive with the factory setting endpoints on the esc.

 

[Motopreserve]

Right. But ESCs like the KDE are also set to particular settings at the factory. So as long as the radio is playing nice - these settings should work...in theory

The product page shows it as being pre-configured to 1060-1860. This is also listed as being the settings that Baseflight likes to see.

I agree, if these settings were messed up at the factory - it would create a world of trouble.

 

[Paul Rosas]

Hi Paul,
Sorry if I'm repeating one of the experts above but I don't have time to read the whole thread. I can say I had a similar experience with a Blackout flying cc3d when I had the ESC update frequency set wrong (to the lowest setting, 50Hz I think?). Check to see what you have it set to, and if it is lower than the max, try setting it to the max as you've got some nice ESC's.

It behaved just as you describe; fine on the bench then oddly wobbly in flight.

I'll more carefully read the thread later when I have more time

Hey bud I just got home and will check into this and let you know what I find....thank you!

 

[Paul Rosas]

Right. But ESCs like the KDE are also set to particular settings at the factory. So as long as the radio is playing nice - these settings should work...in theory

The product page shows it as being pre-configured to 1060-1860. This is also listed as being the settings that Baseflight likes to see.

I agree, if these settings were messed up at the factory - it would create a world of trouble.

That's kinda my thoughts but GetFPV was no help but pretty much said if I want to send them back I can but it would take weeks to check into and see if its all legit, I might as well just buy new esc's because it would be quicker. Whats the worst case if I do calibrate them?

 

[Motopreserve]

I can't imagine that there would be much of an issue of you calibrate them. They are supposed to be SimonK (which I've flashed MANY times).

Check into @crayfellow suggestion, and worst case, try the calibration. You can always send them back after you give it a shot.

Figure out your weight/thrust ratio too. 30% seems awfully low for hover.

 

[Paul Rosas]

Couple things....

Definitely do the stick cal in the Taranis. This makes sure that the sticks are all calibrated and working correctly. Secondly, if you are hovering at 30%, you are way overpowered. You might need to look into balancing the power to weight ratio with some different props???

Make sure you are in "Rate" mode - this is the Naza/Flip32 version of Acro (sounds like you are in this mode in settings, but not in flight characteristics. Make sure when you select the flight mode, it's being saved to the board.

I would try the test with t he motors on the bench - but using the Taranis.

I have used the calibration on the Taranis but will try doing it again. I believe it to be in rate mode but I'm new to cleanflight, I have the flight modes all chosen off...no angle and no horizon chosen....this should mean its in rate right? everything saves good but still all shakey. You are right with its in this mode but flight characteristics seem like it is in horizon or something.....uggg...lol

 

[Motopreserve]

Also, make sure if you do the ESC cal that you have no expo on the sticks.