Limp Gimbal

Vegasrobbi · May 9, 2018

With both my Solo 1 - stock Pixhawk, and Solo 2 - Open Solo Green cube; after 8-10 minutes in follow mode the gimbal goes limp.

I thought this might be the gimbal wearing out or getting hot but once I switch back into FLY mode the gimbal works again. It's somewhat random not happening on every flight.

Both of these Gimbels have some hours on them and I don't remember this happening early on any ideas is appreciated?

Phillip Low · May 10, 2018

Forgive me I cant help this, but, have you tried FLYagra?

IrishmanPDX · May 10, 2018

What about other modes? You know it goes limp in follow mode after 8-10 minutes, have you tried any other the other modes to see if it's just "follow" related or if it's in every other mode except "fly".

No way I'm going to beat the FLYagra comment, so I'm left being humbled and serious.

XevetS · May 10, 2018

Phillip Low said:
Forgive me I cant help this, but, have you tried FLYagra?

Lmao, I'm voting this "the best comment of the year"....Great post @Phillip Low

RichWest · May 10, 2018

Vegasrobbi said:
I thought this might be the gimbal wearing out or getting hot but once I switch back into FLY mode the gimbal works again. It's somewhat random not happening on every flight.

Sounds like an overload of sorts, strange that it is two gimbals and two birds. When you say limp, what does that mean exactly? The gimbal goes dead limp, pointed down and tilted to the side. Or just tilted off to the side, losing camera level.

Also, is the same camera being used between the two gimbals? What are the settings? 2.7k 60fps M... 8:32 minutes is the time a new file is started...when in full light conditions.

fwiw, I'm just a Gimbal Practitioner. There is likely an organic remedy for this issue....

SkycamJoe · May 11, 2018

Phillip Low said:
Forgive me I cant help this, but, have you tried FLYagra?

U said if first...congrats!

just_bruce · May 11, 2018

This does indeed sound like a camera-related issue. If you are using one of the higher bitrate setups and a slightly dodgy MicroSD card, the camera can occasionally become very laggy in talking back to the gimbal. Which, for whatever reason [I haven't delved deeply into this] when combined with extra horsepower being needed on the companion computer [Follow mode, some Cable Cams, etc...] causes the gimbal to go into low-torque mode.

OR seems to anyways. YMMV..

Jhanley · May 12, 2018

This happened to me after a hard landing. The hdmi connection pulled off from its soilder & that was enough to do it. Had to buy another gimbal.

Vegasrobbi · May 12, 2018

Thanks for the feedback, I think any and all of the above may be the culprit.

Rich I'm using two different GoPro 4 Black's. Both gimbals have a lot of hours on them what I don't get is why when I switch modes does gimbal operation return? Not every time though.

This has happened with two different Solo's with two different gimbals and camera's. The white Jeep is being followed by Solo #1 with the stock PH, the green Jeep Solo #2 with Open Solo and the green cube.

What is consistent is towards the end of the flight the gimbals fail. If I reboot there is a 50/50 chance the gimbal will work in follow but it usually will work in FLY or manual. This leads me to believe it is software related?

I would replace the gimbals but with the current prices I am looking for an alternative solution. The SD card thing may have an affect. With my Halo if I unplug the GP or remove the SD card the gimbal freaks out I will look into that.

No thanks on the FLYagra I don't want to get annoying calls during dinner from a guy with a foreign accent from the FLYmarcy.

Damien · May 12, 2018

Vegasrobbi said:
Thanks for the feedback, I think any and all of the above may be the culprit.

Rich I'm using two different GoPro 4 Black's. Both gimbals have a lot of hours on them what I don't get is why when I switch modes does gimbal operation return? Not every time though.

This has happened with two different Solo's with two different gimbals and camera's. The white Jeep is being followed by Solo #1 with the stock PH, the green Jeep Solo #2 with Open Solo and the green cube.

What is consistent is towards the end of the flight the gimbals fail. If I reboot there is a 50/50 chance the gimbal will work in follow but it usually will work in FLY or manual. This leads me to believe it is software related?

I would replace the gimbals but with the current prices I am looking for an alternative solution. The SD card thing may have an affect. With my Halo if I unplug the GP or remove the SD card the gimbal freaks out I will look into that.

No thanks on the FLYagra I don't want to get annoying calls during dinner from a guy with a foreign accent from the FLYmarcy.

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it's too weird that this happens on two different rigs with different cameras, so it must be a common denominator. using same SD card? same controller, tablet and App? I would start by changing controller, if no change then change tablet, then app... then if it still fails on both get a new high end SD card (if you are using the same one for both cameras or the same type that isn't something like a san disk extreme pro).

RichWest · May 12, 2018

I had written the following thought previously, held it in reserve until your reply with some details. Thanks for the video it does say a lot. No question it is an overload condition you are having, the why is perplexing and with two Solos & Gimbals. I've never had a persistent event like yours, momentary at best due to aggressive flying or excessive wind loading. So I have no clue how or why the system reacts to a real overload event, i.e. shuts down all gimbal motors.

Just a thought, but your environment is fairly dusty and you typical fly low to the ground. The gimbals have bearings on all the axial motors, more of a load bearing support for the drive shafts. None rotate beyond 180 degrees, which allows any contamination and wear to localize on the bearings.

Having taken a few gimbals apart I get to see how everything ticks and where are the weaknesses. The bearings do collect dust, the Roll motor bearing collects the most. I've pulled a few and they can get crunchie. They clean up fine, but only when they have been removed from the gimbal.

Combining both thoughts, lack of full rotation and dust accumulation, could a dirty bearing inhibit the motor's ability to rotate easily? If the resistance is persistent enough, I would think the motors could overload. Do you ever check the gimbal motors for excessive heat when this event occurs?

Like I said, it is just a thought....

Curious, do you have any non-stock anything on or around the gimbal? Alternative HDMI or Data cables?

Damien · May 12, 2018

i can also add that i had a limp gimbal issue whilst in automated mapping that was related to the SD Card, changed back to high end cards and it went away

looninho · May 12, 2018

Vegasrobbi said:
Thanks for the feedback, I think any and all of the above may be the culprit.

Rich I'm using two different GoPro 4 Black's. Both gimbals have a lot of hours on them what I don't get is why when I switch modes does gimbal operation return? Not every time though.

This has happened with two different Solo's with two different gimbals and camera's. The white Jeep is being followed by Solo #1 with the stock PH, the green Jeep Solo #2 with Open Solo and the green cube.

What is consistent is towards the end of the flight the gimbals fail. If I reboot there is a 50/50 chance the gimbal will work in follow but it usually will work in FLY or manual. This leads me to believe it is software related?

I would replace the gimbals but with the current prices I am looking for an alternative solution. The SD card thing may have an affect. With my Halo if I unplug the GP or remove the SD card the gimbal freaks out I will look into that.

No thanks on the FLYagra I don't want to get annoying calls during dinner from a guy with a foreign accent from the FLYmarcy.

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I've almost the same issue as your GC Solo until I crashed my Solo. I didn't try other mode than FLY, it was random also and I couldn't control GP4B when it happened.

So my gimbal doesn't work anymore...my Solo sleeps in the backpack saddly!

Vegasrobbi · May 12, 2018

Seems the best thing would be to teardown and inspect; these gimbals have been exposed to a lot of dust and dirt. Is there a good teardown video? Don't know what this guy is on about but he suffers from the same condition. I'll also try a different SD card.

RichWest · May 12, 2018

I got nothing on the tear down, it's just slow work. There is a tear down thread here, shows most of the components. That was really helpful to me for my first tear down.

Most overlooked is the little grub screw on the end of the shafts, 1.3mm I believe. Releasing it will allow you to remove the obvious screws retaining the given axial part. Pulling the ribbon either from their connectors or off the yaw arm is a slow process.

As to the video, more power to the guy if it worked. I don't think that is your problem, as they do work correctly for some period.

Still...Curious, do you have any non-stock anything on or around the gimbal? Alternative HDMI or Data cables? Also what app are you using for follow mod?

Vegasrobbi · May 12, 2018

OK I'll check that thread Googling on YT netted few results.

Everything is stock, I have the flexible cable but never installed it. I've tried with and without an ND filter. Being a GP4B no weights were required and balance seems spot on.

I'm using the 3DR Solo app with a Mini 4 for dynamic altitude. I like Solex but my Nexus 7 does not have a baro.

RichWest · May 13, 2018

If you're disassembling, the hardest part is releasing the ribbon from the FPC/FFC connectors. I use a sharpened dental tool to scrape the adhesive off layer by layer. Once relatively clean I nudge up or out the gate holding the ribbon. The adhesive is really random and can be slopped over the connector as well, causing further problem.

Also I found the 3DR supplied screw driver fits all the screws better than anything I had. The philips' screws are of Japanese standards.

Everything else is intuitive.

If I were you, I'd try a less intrusive method first. Compressed air and maybe a little lube on the Roll bearing. If it doesn't help then tackle the disassembly.

Sorry you are experiencing a problem(s). I really don't have the answers, it's just an observation from the mechanical side. Bruce makes good points and is worth looking into. Also worth a chat to 3DR for their take on the problem...

just_bruce said:
This does indeed sound like a camera-related issue. If you are using one of the higher bitrate setups and a slightly dodgy MicroSD card, the camera can occasionally become very laggy in talking back to the gimbal. Which, for whatever reason [I haven't delved deeply into this] when combined with extra horsepower being needed on the companion computer [Follow mode, some Cable Cams, etc...] causes the gimbal to go into low-torque mode.

OR seems to anyways. YMMV..

RichWest · May 14, 2018

Hey I found some representative photos for grit and grime found on the gimbal bearings. The lower one is off the roll motor, the one mentioned above. And then you can see the Yaw motor's bearing in the bearing tray above that. The user flies FLA and had maybe 20-30 hours on the gimbal.

RichWest · May 15, 2018

RichWest said:
If you're disassembling, the hardest part is releasing the ribbon from the FPC/FFC connectors. I use a sharpened dental tool to scrape the adhesive off layer by layer. Once relatively clean I nudge up or out the gate holding the ribbon. The adhesive is really random and can be slopped over the connector as well, causing further problem.

Here's a photo of a removed main circuit board, showing the FPC/FFC connectors. Connector J4 is the HDMI ribbon and J3 is the power and control ribbon. J4's latch flips up and J3's latch pulls over the ribbon. This is prior to cleaning up after removal.