DJI RONIN PRO SUPPORT

[Sebastian Moretto]

Okay, the briefcase mode test does not look terribly encouraging. When I balance the rig on the stand - it stays put pretty much wherever I turn it - and turn it into briefcase mode with the motors powered off, the balance of the whole rig shifts quite dramatically. I actually have to completely rebalance the rig, both on the roll and the pan axis to get it work the way one would expect. When I turn it back into normal mode and put it on the stand, the balance is totally off, as one would expect after rebalancing it.

No wonder it didn't want to go into briefcase mode when powered on. The motors have to fight a dramatic balance problem...

 

[Wayne Mann]

HI guys,

I will try to shed some light on what may be happening here with the different balance issues going from standard mode to briefcase mode. On my Ronin when balancing the two tilt axis, especially the vertical tilt axis I get a slightly different balance read when the camera lens is pointing straight up as opposed to the lens pointing straight down. The reason for this is because the two pivot shafts for the tilt axis are either slightly out of alignment or the vertical tilt bars that support the camera plate, sensor and breakout box are putting stress on the two tilt pivot axis bearings. When you stress those two pivot bearing or put them under a twisting load it will cause the gimbal to give you a false balance point and depending on the severity of the bind it will make it nearly impossible to find the true balance point. This is why when you get the gimbal balanced in standard mode and then switch to briefcase mode the pan balance and roll balance shows as being off slightly or way out depending on your particular gimbal.

It is important to note that I have seen this very issue in just about every gimbal that has a bearing support for the tilt axis on both sides of the camera including Freefly's original multirotor mount, my own custom designed mounts and several others.

In a perfect world the pivot shaft for the support side of the gimbal, opposite side from the motor would have a machined ball on the pivot shaft that is centered in the support bearing so that if the camera mount tilt structure is not built perfectly square it will still have no binding or preloading issues on the tilt axis bearings.

I hope that this helps with understanding why everyone is getting different balance reading in different configurations.


Wayne Mann

 

[Frederic Sturm]

HI guys,

I will try to shed some light on what may be happening here with the different balance issues going from standard mode to briefcase mode. On my Ronin when balancing the two tilt axis, especially the vertical tilt axis I get a slightly different balance read when the camera lens is pointing straight up as opposed to the lens pointing straight down. The reason for this is because the two pivot shafts for the tilt axis are either slightly out of alignment or the vertical tilt bars that support the camera plate, sensor and breakout box are putting stress on the two tilt pivot axis bearings. When you stress those two pivot bearing or put them under a twisting load it will cause the gimbal to give you a false balance point and depending on the severity of the bind it will make it nearly impossible to find the true balance point. This is why when you get the gimbal balanced in standard mode and then switch to briefcase mode the pan balance and roll balance shows as being off slightly or way out depending on your particular gimbal.

It is important to note that I have seen this very issue in just about every gimbal that has a bearing support for the tilt axis on both sides of the camera including Freefly's original multirotor mount, my own custom designed mounts and several others.

In a perfect world the pivot shaft for the support side of the gimbal, opposite side from the motor would have a machined ball on the pivot shaft that is centered in the support bearing so that if the camera mount tilt structure is not built perfectly square it will still have no binding or preloading issues on the tilt axis bearings.

I hope that this helps with understanding why everyone is getting different balance reading in different configurations.


Wayne Mann

That is certainly a good point, but I tried balancing it with several variations of tiny different readings on the vertical tilt axis scale on both sides to see if this has any influence on the pan axis balance - it doesn't. With your finding and what Sebastian experiences matching my findings so closely, my bet is on manufacturing imprecision to varying degrees, and on different axes, leading to some Ronins being near perfect, some kind of ok unless you move it fast in a certain axis, and some others barey useable. I'll have a chance to upload our video soon to show how it even affects slow moves on some ronins.

 

[Frederic Sturm]

Finally got a chance to upload the video. It is set to "unlisted" as I'm only interested in solving the issue, not making other people nervous about the Ronin or something, you know how things get interpreted on the net...

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

Please see how in normal underslung mode, fast rocking of the Pan and tilt axes are working perfectly, but rocking the roll axis causes a motor shutoff in the pan axis.

On this Ronin, that shows the issue rather severely, it can be provoked by as much as one sudden move as you can see a bit alter in the video.

Towards the end of the video, you can see that even a slow move is enough to cause it, making this particuar Ronin almost unuseable.

Please note, this Ronin was perfectly balanced before this test.

 

[vincent van schijndel]

that issue is not really an issue imo because:
- you are with your roll rocking also tilting a bit, which also moves pan axis a bit. probably the issue is gone when disableing smoothtrack.
- and this is a situation that will never happen during normal shoot

 

[Frederic Sturm]

Vincent,

this issue is there no matter if smoothtrack is on or not, as I've described in detail before. It shouldn't matter that other axes are moved a slight bit, as you can see in the beginning of the video that fast moves in the other axes cause no problem.
I see it as being a issue, as sudden roll moves can always happen in a car, helicopter or other kinds of action shooting. Others are seeing it as being an issue, and finally, this video certainly shows enough of an issue for DJI to recognize it and research the problem.

 

[Peter Majtan]

Fredric - I've just seen the video and no way that rig is balanced.
Given the DSLR you have on it that rear section is way too back on the horizontal bar coming out from the pan axis.
You have it at a position where it is normally balanced for heavy RED setup.
This also clearly shows when you move it more slowly towards the end if the video as you roll the ronin "pans" to the respective side because of the imbalance. This would of course trigger your issue and especially when you trashing it around like that.

This is a precision instrument designed to stabilize (the imperfection of a) normal motion of an operator - not to be able to handle being trown to bunch of gorillas to toss it about in a cage... ;o)

Simple thing - turn of the motors and roll the Ronin in the same way (super slow) and you will see it will react in the exact same way.
Please balance the 4th alignment properly and try again...

:sifone: Peter

 

[Frederic Sturm]

Fredric - I've just seen the video and no way that rig is balanced.
Given the DSLR you have on it that rear section is way too back on the horizontal bar coming out from the pan axis.
You have it at a position where it is normally balanced for heavy RED setup.
This also clearly shows when you move it more slowly towards the end if the video as you roll the ronin "pans" to the respective side because of the imbalance. This would of course trigger your issue and especially when you trashing it around like that.

This is a precision instrument designed to stabilize (the imperfection of a) normal motion of an operator - not to be able to handle being trown to bunch of gorillas to toss it about in a cage... ;o)

Simple thing - turn of the motors and roll the Ronin in the same way (super slow) and you will see it will react in the exact same way.
Please balance the 4th alignment properly and try again...

:sifone: Peter

I agree that the first moves were kind of extreme, but it was more to show that the Ronin takes those fast moves fine on both other axes - which is remarkable! But then in the roll axis it wont even take slower ones, as you can see later in the video. I do beleive though, that during use of the gimbal in a car or helicopter a sudden move can always happen and shouldn't ruin your shot.

And since nobody wants to believe that it is well balanced (as well as any possible with the de-centered pan axis), I will make a new video showing perfect balance and then the issue appear in one take... could you for now please believe it is properly balanced? We threw a D800 on it for this video, but it happens with a RED just the same way. I personally put the D800 on and balanced it before that video was made. It was made at the dealership and both me and the dealer confirmed the balance.

 

[Wayne Mann]

Hi Guys,

I will throw one more thing out there. I did a lot of playing with my Ronin last night. If I rock my handle bar back and forth in the roll axis and the camera never moves around meaning that I am rotating the unit in a way that keeps the roll axis shaft sitting perfectly still, I can't rock the handle bars fast enough to cause the pan axis to do anything stupid, BUT if I am just rocking the handle bars in a lazy manner and the camera is moving around a lot basically being pulled in several directions I can cause the gimbal to get pissed off and everything goes to hell in a hand basket. If you are filming out the side of a real or full scale helicopter and it causes the kind of movement required to cause this issue I believe that you are going to probably be more concerned with the fresh pile of you know what in your shorts.


Wayne Mann

 

[vincent kardasik]

Peter,
First time I used my Ronin, I didn't notice any noise.
Now after balancing it, I switch it on, do the auto-tune then kill the motors to plug the Lcd cable, regular R3D cable, then when I re-activate the motors, it starts doing a continuous noise, no shaking, no vibration, just a weird noise.
Have you ever experienced that?

 

[Frederic Sturm]

Hi Guys,

I will throw one more thing out there. I did a lot of playing with my Ronin last night. If I rock my handle bar back and forth in the roll axis and the camera never moves around meaning that I am rotating the unit in a way that keeps the roll axis shaft sitting perfectly still, I can't rock the handle bars fast enough to cause the pan axis to do anything stupid, BUT if I am just rocking the handle bars in a lazy manner and the camera is moving around a lot basically being pulled in several directions I can cause the gimbal to get pissed off and everything goes to hell in a hand basket. If you are filming out the side of a real or full scale helicopter and it causes the kind of movement required to cause this issue I believe that you are going to probably be more concerned with the fresh pile of you know what in your shorts.


Wayne Mann

That is a very good point. If you look at my video, you can see, especially towards the end with the slower moves, how the camera stays pretty still and I try to move the handlebars around the roll axis.

In regard to xxx in my pants, I fly and instruct flying fullsize helicopters for a living (my second job, next to, and in connection with camera work and movie production), and theres not much that could scare me in that way, but I do understand your point =) I still know what kind of moves we're asked to do when filming with cineflex and the like, and yes, moves that could cause this do happen. Depending on the type of shot, often enough directors and DPs get really sick but have us keep going as they love the resulting images =) With what I saw on this other gimbal, a steep turn would be enough. Or lets say a steep corner on a racetrack in a car, that'd do it.

 

[Greg Faysash]

I am having issues with briefcase mode as well. I've flown several cameras already, and I can balance on all axis almost perfectly (better than in the instructional videos). BUT once payload gets to 10lbs (4.5 kg) or above my Ronin goes crazy when put into briefcase mode. I've tried different stiffness and speed settings - no luck. Any advice?

 

[Peter Majtan]

Peter,
First time I used my Ronin, I didn't notice any noise.
Now after balancing it, I switch it on, do the auto-tune then kill the motors to plug the Lcd cable, regular R3D cable, then when I re-activate the motors, it starts doing a continuous noise, no shaking, no vibration, just a weird noise.
Have you ever experienced that?

Hi Vincent, the RED LCD cables are really stiff and they will cause quite a large force acting against your balanced camera. Either use one if the super slim LCD cables that are very flexible and light, or the best is just to go wireless...

:sifone: Peter

 

[Peter Majtan]

I am having issues with briefcase mode as well. I've flown several cameras already, and I can balance on all axis almost perfectly (better than in the instructional videos). BUT once payload gets to 10lbs (4.5 kg) or above my Ronin goes crazy when put into briefcase mode. I've tried different stiffness and speed settings - no luck. Any advice?

When switching to briefcase mode all you need to do is hold the system steady and roll the handles 90 degrees to the side without paning or tilting. The Ronin will switch to the briefcase mode smoothly. Similarly if you want to go to the upside down mode - turn the ronin so the camera points towards you then flip it 180 degrees along the tilt axis withou inducing roll or pan. The Ronin is programmed to sense those motions to initiate the various modes. I will make a short video when I get a chance and DJI should release similar videos soon as well...

To make sure you are not having other issues - try orienting the Ronin to briefcase mode while the motors are switched OFF (kill switch) and check how is your balance in the briefcase mode. For this you can put one handle on the ground or table and just hold the other handle with one hand - leaving your other hand free to support the camera to prevent any violent movement in case your balance is off...

:sifone: Peter

 

[Peter Majtan]

Frederick - I will take your word for it and assume your rig is balanced.

However - and I am saying this with smile on my face and mean no offense ;o) - seeing videos of people handling precision (or actually any) professional film equipment like that makes me wish there was a PETA equivalent organization for abused gear... ;o)

About DP's and / or clients getting sick in the air - I won't allow any crew members to come on board without having taken Dramamine before the flight. I, myself an ex-airforce-pilot (Mig 21 & 29) and having practically grown up in a helicopter, take the drug before each flight. It is easy to induce motion sickness when getting confusing signals from your inner ear and feeding your visual core from the camera's monitor - where the camera is not oriented in the same exact way as your/their head - which is all the time... ;o)
There is no playing egos on these kind of jobs...

Coming back to your issue - I am really unable to reproduce it UNLESS I unbalance the 4th alignment AND move the rig violently beyond anything I would even encounter on a job...

And finally about G-forces in high speed turns - yes, this affects all but the 6-figure plus gimbals. Lateral G-forces prevent the gimbal's IMU (inertial measurement unit) from working properly as now you are mixing both your normal motion innertia with the G-forces. As you said - even if you do a high speed turn in a car - the Ronin will drift out of level and return back to level when the G-forces disappear. With enough practice the camera operator can correct for this with the remote controller...

Another factor that comes to play at high speeds is the wind resistance. Depending on your camera setup's physical shape - once you exceed certain speeds that resulting wind forces acting on the gimbal will overpower the motors and trigger the safety kill.
So do keep your gimbal shielded from the wind if you are after high speed motion...

:sifone: Peter

 

[Joe Lawry]

I can definitely confirm my unit shows the same issues as in the youtube video a few posts back. My rig is 100% balanced. Obviously under normal conditions you probably wouldnt end up causing the motors to cut off like they do..

Breifcase mode - Ive thought i've had issues with BC mode however i think you just have to be patient with it and roll the handles sideways and then hold it there for almost a Second before the unit goes into BC mode. Be Patient with it.

I went out testing again today and looking at the footage I am noticing a lot of pan wobble in the footage. I really hope DJI are a bit more onto it with the next firmware.

 

[vincent kardasik]

Hi Vincent, the RED LCD cables are really stiff and they will cause quite a large force acting against your balanced camera. Either use one if the super slim LCD cables that are very flexible and light, or the best is just to go wireless...

:sifone: Peter

Thanks for your reply Peter and also million thanks for the time you spend here helping all of us!

 

[Frederic Sturm]

I can definitely confirm my unit shows the same issues as in the youtube video a few posts back. My rig is 100% balanced. Obviously under normal conditions you probably wouldnt end up causing the motors to cut off like they do..

Breifcase mode - Ive thought i've had issues with BC mode however i think you just have to be patient with it and roll the handles sideways and then hold it there for almost a Second before the unit goes into BC mode. Be Patient with it.

I went out testing again today and looking at the footage I am noticing a lot of pan wobble in the footage. I really hope DJI are a bit more onto it with the next firmware.

Thanks Joe!

 

[Frederic Sturm]

Frederick - I will take your word for it and assume your rig is balanced.

However - and I am saying this with smile on my face and mean no offense ;o) - seeing videos of people handling precision (or actually any) professional film equipment like that makes me wish there was a PETA equivalent organization for abused gear... ;o)

About DP's and / or clients getting sick in the air - I won't allow any crew members to come on board without having taken Dramamine before the flight. I, myself an ex-airforce-pilot (Mig 21 & 29) and having practically grown up in a helicopter, take the drug before each flight. It is easy to induce motion sickness when getting confusing signals from your inner ear and feeding your visual core from the camera's monitor - where the camera is not oriented in the same exact way as your/their head - which is all the time... ;o)
There is no playing egos on these kind of jobs...

Coming back to your issue - I am really unable to reproduce it UNLESS I unbalance the 4th alignment AND move the rig violently beyond anything I would even encounter on a job...

And finally about G-forces in high speed turns - yes, this affects all but the 6-figure plus gimbals. Lateral G-forces prevent the gimbal's IMU (inertial measurement unit) from working properly as now you are mixing both your normal motion innertia with the G-forces. As you said - even if you do a high speed turn in a car - the Ronin will drift out of level and return back to level when the G-forces disappear. With enough practice the camera operator can correct for this with the remote controller...

Another factor that comes to play at high speeds is the wind resistance. Depending on your camera setup's physical shape - once you exceed certain speeds that resulting wind forces acting on the gimbal will overpower the motors and trigger the safety kill.
So do keep your gimbal shielded from the wind if you are after high speed motion...

:sifone: Peter

Thanks for believing me, and please see Joes confirmation above and a few more earlier.

No offense taken at all =) I'm not treating any of my (and others) equipment in a bad manner - come by and look at my gear and how I protect it, and the care I take in using it - some might say it's obsessive... But just like you might test the brakes of a new car before you go speeding on the freeway, I like to know the limitations of my gear, so I test it - and that might well involve testing such fast moves on a gimbal. Better have it fail now than not know the limits and ruin a $$$$$ day, right? Please don't think I treat my gear like as you said "a bunch of gorillas" regularly =) =)

While I don't force anyone to take medication to come on board, I keep a pack of Vomex (based on diphenhydramine, like Dramamine) ready for my passengers for the worst case - although its almost never necessar. I've seen Biobands (P6 accupressure point bracelets) being very effective, too and always have some of these ready. Thankfully, I myself am not too sensitive to motion sickness and avoid taking any medication before taking control of an aircraft. our regular operator isn't very sensitive either - licky I guess =)

I wouldn't expect the Ronin to be a Cineflex of course, and would never complain if it doesn't take G-Forces well. I was just thinking about examples of where a sudden roll movement could happen. And I agree, shielding it from strong wind is likely very important, great point.

 

[Dave Blackham]

Is there a Ronin dovetail clamp available same config that fits the top mount so Ronin can be used on a crane as a remote stabilised head ? I guess we can machine some up but would be good if this is available as a stock part.