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Major vibration

I have been reading about this vibration issue for several days now...my Inspire has not done this and seems to be very tight at the T joint...I certainly was looking for this, thanks to everyone with this issue.
 
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#16 is not in the version of the manual I downloaded when I got my Inspire (Jan 8). I just re-downloaded the manual and #16 is there. What's interesting is that that DJI did not change the manual date or version number. The download site on DJI.com still says 2014-12-31 v1.0. I had been relying on those dates so that I know when to download new manuals. Anyway, when I reported the problem to DJI Jan 9, they said they had never heard of this problem before. The fact that they updated the manual suggest that are responding a little bit.

Thanks Rob. Interesting. What did it say exactly? Can you copy and paste from the prior version?
 
It's probably more an issue of the motors being imbalanced rather than the arms being loose. Even if the arms were stiff, they would wobble similar to the slo-mo vids if the motors are imbalanced. Tahoe Ed said that only DJI can balance the motors (at least until someone figures out how to do it themselves) so if it continues, it's likely you'd have to ship it back to DJI for service.

It's definitely not the motors. I checked.

You can check for vibration too using an iPhone and the 'Vibration' app: http://itunes.apple.com/app/vibration/id301097580

Here's how to test:
 
I’d be willing to bet that there’s a fundamental resonance issue somewhere in the frame and those “loose” bits to facilitate the retracts just magnify it.
 
The issue is not like an unbalanced prop or motor where you spin it up and you get vibration period. It's a harmonic vibration, much like a kid on a swing where small kicks of the legs add up into large swings. I doubt that play in the T-connector is the root cause, it just seems to make the quad more prone to going into oscillation. In my case, tightening the joint fixed the problem. However, I have seen a video of another Inspire where the joint looks solid and the vibration is still there.
 
Anyone else got this?

"Dear Sir,

For your craft vibration problem, we got a quick fix for you. At the moment we are working on the video tutorial. Please wait for our further contact.

Appreciate your patience and support of DJI product.

With regards
DJI Technical Support10
 
I’d be willing to bet that there’s a fundamental resonance issue somewhere in the frame and those “loose” bits to facilitate the retracts just magnify it.
agreed and most importantly the motor arms where you have a node in the middle (t-junction) with rotating mass at both ends...and you wont be able to dampen the resonant vibration unless there is direct contact, with some pressure, to damping material, i.e. the rubber pads on the bushings. The truth is you can never balance anything perfectly so there will always be some minimal level of driving force either in the props, motors or both that will "seed" a resonant vibration...all you can do at that point is change the natural freq of the frame with counter weights (not an option) or contact with damping material (source: I happen to be a certified vibration analyst)
 
Anyone else got this?

"Dear Sir,

For your craft vibration problem, we got a quick fix for you. At the moment we are working on the video tutorial. Please wait for our further contact.

Appreciate your patience and support of DJI product.

With regards
DJI Technical Support10

Jacob thanks. Was this from an email or chat? If email can you post what you reported?
 
I know this is a lot but here's what I could find of my communication..
The "responses" aren't worth posting as we all know their generic format.
The end has some news from them that I just received.

Jan 10
"Hi there,

I have an issue with shaking/vibration in the right arm when the landing gear is raised.

It is observable in the video I have attached but has been more extreme off of camera.
I have seen the same happening to others on You tube and Phantom Pilots forums.

Please advise me on how to rectify this ASAP.
Thank you,"

Jan 11
Online support- no transcription

Jan 12
"please tell me what is going on, this is the third time I have contacted you and I have still had no response…
You told me on both occasions that you’d get back to me in the next hour!"

Jan 13
-Phone conversation saying that they had no record of my correspondence! Apparently they don't share records with dji&Inspire support. WTF..

Jan 14
"Please let me know what is going on with my shaking I1. I have emailed, online chat and spoken to support over 5 times now and received nothing back.. You always say 1 hour and then never reply!
What's taking so long?"

Jan 15 18:31
"please let me know what is going on with my shaking I1. I have emailed and spoken to support over 6 times now and received nothing back.. I have posted videos and been talking to people on forums but haven't been given any actual advice from DJI. I haven't flown for days as the craft is shaking so much and I don't want to crash it (obviously), it is driving me crazy and losing me money.
When ever I speak to support they always say wait about 1 hour and then never reply!
Please tell me what is going on.."

17 Jan
"This is Jacob from Bristol, UK. Again.
I've sent these videos to you so many times now.. I don't understand why I have to start again every time?
The right arm is vibrating and feels loose. I have only flown it twice and am too wary to fly incase it crashes due this problem.
I know that many others have this issue and just want to know what to do about it. There are records of my case so I'd appreciate it if you could find them and download the attachments.
I have sent the videos yet again.."
-I just gave up banging my face into a barbed wire fence and followed the advice in this thread to resolve the problem.
Then out if the blue I got the response in my last post about the upcoming video with a "quick fix" and since responding to that I literally just received this:

Jan 31, 17:45

Hi Jacob,

We are working on modifying the video, it would be available next week.

Thanks for your patience.

Have a nice weekend.

DJI Tech support

-They take the piss. Seriously..
 
Yes well.... it's quite clear ..... They are working on modifying the video! They will edit out the vibrations on the video and then send it back to you.

There problem solved... if you can't see it, it doesn't exist :p

Sorry - not helpful I know.... It DOES appear however that they are working on a solution.
 
Hi, I have exactly the same vibration issue...so very interesting to hear what DJI will be suggesting. In my case the vibration does not seem to be persistent.. some times it is there, sometimes not. I t seems to be more present when hoovering at low height,although may be it is just because in this condition it is closer and easier to see !
 
Yes I've noticed that it seems more pronounced at low levels but before adjusting it I was getting jello in my shots at all heights. I wonder if the fix will involve opening the arm connections?
 
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just noticed that vimeo automatically adjusted the frame rate! It was meant to be a slow motion, but it is not any longer! will try and find a way to upload slow motion as well. Sorry, not sure it can be seen like this !
 
Another day, another flight report. I got the prop locks in and decided to try them with a tweak to the aircraft.

First, some background.

Someone on Youtube (and I think in this thread!) saw my videos where I had jello in the day and by looking at the props suggested my arms were coming loose. I was seeing jello on bright days, even when I applied a stronger 3-stop ND filter. I was convinced I needed even a stronger filter, but given the late afternoon light as well as other's much brighter daytime videos, this made no sense sometimes.

Looking at all my flights, where I got jello it looks like the arms were shuddering in a kind of harmonic vibration: the same kind of vibration my P2 H3-3D gimbal had before I applied sorbothane. The arms sometimes shudder and wobble causing a visible harmonic shake that leads to jello. It is not noticeable at night or sunset due to the slow shutter, but I can sometimes see it in the bright sun during FFF and even in hover sometimes.

Now most of my flying has been in low light so far. So I haven't seen much of it. The vibration on the arms is still sometimes noticeable in those flights too when you look at the motors and props with the camera but the slow shutter evens it out on footage. My few bright sun flights had jello both in hover and in FFF, and in each case when I looked at the motors and the arms... they were shuddering while the rest of the craft was relatively stable. The harmonic shaking in the arms was noticeable on camera (when I aimed at the motors to see) whenever I had the issue in calm winds. Like Alessandro mentioned, it's not all the time, but enough to notice.

Not every moment of every bright sun video I filmed (all 3 of them) had this, but most of them did in FFF.

Today, I checked the arms on the ground. They were noticeably wobbly on both sides. The motors shook easily. I applied a temporary fix that was suggested by Rob here inside the T-joints by adding a little rubber to the existing rubber to help the compression clamp grip better (but not otherwise tightening any bolts), which ensured the arms could still raise and lower fine but removing pretty much all of the gross wobble. I am not recommending you do this (it's my quad, not yours and if you mess up you can over tighten the joint and possibly lock it up, burning out your raise/lower motor) but it is reversible, but it definitely helped. For the record, I used 3M VSB tape. It worked perfectly, as it is basically sticky rubber.

The key goal for me was to remove the harmonic shaking in the arms to isolate any remaining vibration to just the gimbal itself.

What better way than to test in insane winds? I could fly freely and aggressively with the prop locks finally installed, and see how the aircraft really holds in insane gusty winds.

I flew in very strong cold wind today at about 12 degreed F with gusts to over 25 MPH. The T joint was tightened and verified before hand.

In my test flight after the fix, there was shake whenever the crazy wind gusted, but not really that wavy jello. To clarify, I pointed the camera at the aircraft and looked. The arms were not shuddering or vibrating like before - they were rock solid. When you saw the wind gust in the trees, you could see gimbal move. It was GUSTY.. and the motors were constantly rapidly changing speed noticeably to keep the aircraft stable. At many points it was at maximum tilt in some direction, shifting rapidly as the wind did.

I was kind of shocked at how well the inspire handled this. The P2 could not have handled this wind safely (I have tried it) without some white knuckle moments wondering if it would even make it home. The inspire can handle it, even in GPS mode, never mind ATTI which you can get more power out of. I rapidly moved it all over the place and it was like it was on rails. I was incredibly impressed once I could finally open this sucker up with the prop locks on.

Back to the footage:

When I turned the camera to look at the aircraft, I could see no shake or vibration in the arms that I saw before. The shake was just the camera gimbal blowing around in the heavy wind. When the wind was still, so too was the image.

That I was able to get any usable footage in this insane wind was shocking. About 1/2 the flight was usable. And when I looked at the aircraft it was wildly adjusting all over the place due to the fierce changing winds, with the gimbal bouncing like a basketball, but the ground remained (mostly, relatively) steady. And the motors and arms were not shuddering or shivering like before.

I definitely need to do more testing tomorrow, in calmer winds, but so far so good. These tests are not yet conclusive for me, but I have hope at least that I can get footage in calmer winds just as good during the day as what I get in the evening, in overcast conditions, etc.

PS - I made a neoprene wrap with velcro that wraps around the battery for cold flights. The batteries have two little velcro strips on each side, and I cut the neoprene to wrap around the back and fit to each side. It's reusable, and the battery was warm at the end of the f-ing freezing cold flight. I will post photos at some point. I got 13 min of flight to 30%, and 15 min to 10%, which is what I get in warmer weather. Without the jacket, the battery drops like a rock quickly when it gets under 50%.
 
lago di Lugano !
what I did to quickly overcome the issue of vimeo adjusting the playback framerate to normal is re-record at normal speed the previous video played back on my laptop in slow motion. lost a bit on quality but worked fine !
 
Just curious to know if anyone did get any updates from DJI on this issue yet ? I am still waiting for more info from them !
 

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