Hey guys,

Im running an F450 that ive had for about 7 months. I recently put an ebay gimbal on it that came with a BGC 2.0 Gimbal Controller. I have been able to dial in vibrations when the gimbal is held in hand or on a support to near none. the gimbal (as at the end of the video) works exactly how id like it to except for when the quadcopter is in flight. I get a series of vibrations, and from the video it looks like its on both pitch and roll. this vibration only happens in flight.


I had mounted the go-pro directly to the frame with the 3m tape on the mounts that came with the go-pro previously, and had not  noticed any vibrations. This is my first time setting up a gimbal, I spent about 10 hours yesterday learing how to program it but Id really like to get this setup flying asap, so any assistance is greatly appreciated.

screenshot.jpg shows my PID settings (with gyro LPF off)

Here is a link to the video  from the gopro on the gimbal.

https://www.youtube.com/watch?v=6meSE_HUZLI&feature=youtu.be

any questions, please ask and i will return an ansewer as promptly as possible. thanks guys!

Chris

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Judging by the oscillations in your video it looks like the gain in your PIDs are set too high.

Well i tried diffrent extremes with the PID and power settings. some to the point that the gimbal was borderline spazzing out, but they all have the same effect. the only thing i havent done is tried mounting the gimbal directly to the frame (i.e. bypassing the vibration dampners.

Hey Chris, I re-watched your video and you're right, it's unlikely that it's your PIDs (or at least not 'just' your PIDs).  When your gimbal powers-up it's perfectly stable and doesn't start to misbehave until it's airborne and from the looks of the wobble I'd say something is either loose or out of balance.

If I were there the very first thing I would do is inspect the motor mounts for damage or loose screws.  Then I would double-check the balance of the props, the prop hubs, and the motor bells. I would also inspect the props for any damage and then check every screw and joint throughout your airframe to make sure it's all tight and solid.

If you're using APC props that require hub inserts then double check to make sure each prop has its insert installed properly. A perfectly balanced APC prop without its insert will be rotating off-center.

If all the above looks good then it may be electrical. If you're powering the gimbal from the same battery that supplies your motors -- either directly or through a BEC -- then try giving it it's own battery as a test. 

great minds think alike. Ill let you know what I come up with, as i think it may be an external vibration interfering with the IMU, which has been my greatest fear. Unfortunatly I dont have alot of the tools i need to check the vibrations on the props and motors but I will check the mounting points.

Ive gone as far as to mount the gimbal to the frame, still picking up interference. I may run some accelerometers on the arms and see if i can single out the issue.

Appreciate the input very much. thanks again for your help.

So i took it back out and tried a few things. First i disconnected the roll and pitch motors from the controller individually and then flew the gimbal with one motor at a time. the virbations were occuring on both axises. I then wired up a seperate battery to run the gimbal in flight. Still having the issue. Ive done about all I can to narrow it down to a vibration issue in the quadcopter. Ill let you know how it turns out,

again thainks for the input.

Hi Chris,  Thanks for the update.  Looks like you've proven the fault is mechanical rather than electrical -- nicely done! There are a number of ways of measure and isolate vibration issues using everything from laser pointers to smartphones but one tool you cannot live without is a high quality prop balancer.  My personal favorite is the Du-Bro "Tru-Spin". Not exactly cheap, but it will handle a very wide range of prop sizes and when used correctly the results are bang-on. If you need help isolating other vibrations lmk.

Hope you have a great Independence Day!

Ended up mounting the gimbal arm directly to the frame, seems to have solved the issue. I believe the rubber grommets on the anti vibration section of the arm was amplifying any oscillations so I removed it completely. thanks for the help guys.

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