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Old Jan 12, 2013, 02:46 PM
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hexa's Avatar
United Kingdom, Scotland, Edinburgh
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Originally Posted by neavissa View Post
So if a bigger camera is gonna be fine,what do you think of my "cutting the Z15 in half" idea?! I believe it is on page 141.... Take a look at the GIF I made to illustrate how it would look like...

thanks,

G
It should work. But am thinking you would get better results if you could find a Cnc engineer to measure and design the needed parts.
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Old Jan 12, 2013, 06:24 PM
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DorianJ's Avatar
Freehold, USA
Joined Jan 2008
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Originally Posted by hexa View Post
Adding a different or heavier camera to the z15 will not damage the z15 motors.
You are more likely to damage the driver board that drives the motors.
Which still won't happen.
The z15 motor driver board has build in fail safe, if the board reads pass a set voltage Amps feedback the z15 resets it self. Eg try panning the mount with radio wile holding on to the mount will reset the z15.

Fail safe protection feature is also noted on Dji firmware release notes.

Adding a different cam is a matter of finding one that fits and can be balanced nicely.

I would say if you have to buy z15 now go with gh2 version. It's bigger with more adjustments. That way you can tinkle with other cams later on. Or wait for a long time on Dji next release.
I think the main question is torque handling, will the motors be able to make fast angle adjustments when stabilizing the added weight of a heavier camera. Kind of like with spinning a bigger prop on smaller BL motors...the motors will not have the torque to make fast enough adjustments therefore the multi will not be as stable compared to running smaller props which will need less torque to spin and will be able to make fast adjustment for a more stable flight. Worse case is you won't experience the great stabilization using a heavier cam compared to using the cams the Zen was designed for.

Even if the heavier cam is perfectly balanced on the gimbal, there is the issue of inertia. For example, when a heavier cam is being stabilized on a rolling right, it will take a lot more torque to get it to roll left during stabilization...much more inertia with a heavier cam (5D3) compared to a GH2. The Zen makes much faster angle adjustments compared to standard servo driven gimbals. This is where torque comes in to play.

As a test, hold a 5D2 in your hand and quickly roll it left and right. Now hold a Nex7 or a GH2 in your hand and do the same...you'll feel the difference in the torque needed to quickly roll left/right.

Only one way to find out!
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Old Jan 12, 2013, 07:40 PM
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Canada, QC, Montreal
Joined Jun 2012
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Originally Posted by DorianJ View Post
I think the main question is torque handling, will the motors be able to make fast angle adjustments when stabilizing the added weight of a heavier camera. Kind of like with spinning a bigger prop on smaller BL motors...the motors will not have the torque to make fast enough adjustments therefore the multi will not be as stable compared to running smaller props which will need less torque to spin and will be able to make fast adjustment for a more stable flight. Worse case is you won't experience the great stabilization using a heavier cam compared to using the cams the Zen was designed for.

Even if the heavier cam is perfectly balanced on the gimbal, there is the issue of inertia. For example, when a heavier cam is being stabilized on a rolling right, it will take a lot more torque to get it to roll left during stabilization...much more inertia with a heavier cam (5D3) compared to a GH2. The Zen makes much faster angle adjustments compared to standard servo driven gimbals. This is where torque comes in to play.

As a test, hold a 5D2 in your hand and quickly roll it left and right. Now hold a Nex7 or a GH2 in your hand and do the same...you'll feel the difference in the torque needed to quickly roll left/right.

Only one way to find out!
Yes i think you right...
But i'm wondering if i choose the zen gh2 but try to manage to fit the gh3 it will be ok for the weight...
i don't think the gh3 it really heavier than th gh2...or i could wait for a zen update for gh3...don't know what to do..
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Old Jan 12, 2013, 08:13 PM
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Freehold, USA
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Originally Posted by animau View Post
Yes i think you right...
But i'm wondering if i choose the zen gh2 but try to manage to fit the gh3 it will be ok for the weight...
i don't think the gh3 it really heavier than th gh2...or i could wait for a zen update for gh3...don't know what to do..
I think the GH2 zen modded to fit a GH3 may work...not a huge difference in size. The GH3 is only about 160 grams heavier than the gh2. There is someone here who has done this mod and is currently testing. I'm curious to hear any updates with stabilization performance.

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Old Jan 12, 2013, 09:53 PM
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Canada, QC, Montreal
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Dji must do a zen-g upgrade for the new gh3! and i will buy it right away
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Old Jan 13, 2013, 05:33 AM
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Joined Oct 2010
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Finally getting around to installing my GH2 zen this morning.

Quick and maybe stupid question, but where should I locate the zen IMU?

In the main body of the S800 or on the top ( machined surface) of the zen gimbal?

Lack of clarity in the manual for this IMHO.
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Old Jan 13, 2013, 05:54 AM
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when will have a new zenmuse firmware with some "rump" to get rid of that horrible "robotic" look movements ??
for one man operation there is no way to make a real smooth shoot , the stop at the end of a pan or pitch is to hard
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Old Jan 13, 2013, 06:14 AM
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Portugal, Lisbon, Cascais
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Originally Posted by plingboot View Post
Finally getting around to installing my GH2 zen this morning.

Quick and maybe stupid question, but where should I locate the zen IMU?

In the main body of the S800 or on the top ( machined surface) of the zen gimbal?

Lack of clarity in the manual for this IMHO.
Usually on the top of the gimbal
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Old Jan 13, 2013, 07:10 AM
United States, MI, Goodrich
Joined Mar 2004
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GCU mount on top right of Z15 with video out facing forward and two ribbons cable facing to center. Two zip ties to mount is all we use.

Hope that helps.
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Old Jan 13, 2013, 08:17 AM
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Originally Posted by hexa View Post
It should work. But am thinking you would get better results if you could find a Cnc engineer to measure and design the needed parts.
Man, I am amazed at how freaking stupid I am, sometimes?! LOL. You are totally right! Instead of "destroying" the gimbal, take the damn thing apart and replace the "pipes" with bigger ones!!! Seriously, you are a genius! (well, compared to me, no big deal!l).

thanks for saving me a bunch of money!

G
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Old Jan 13, 2013, 08:37 AM
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Originally Posted by DorianJ View Post
I think the main question is torque handling, will the motors be able to make fast angle adjustments when stabilizing the added weight of a heavier camera. Kind of like with spinning a bigger prop on smaller BL motors...the motors will not have the torque to make fast enough adjustments therefore the multi will not be as stable compared to running smaller props which will need less torque to spin and will be able to make fast adjustment for a more stable flight. Worse case is you won't experience the great stabilization using a heavier cam compared to using the cams the Zen was designed for.

Even if the heavier cam is perfectly balanced on the gimbal, there is the issue of inertia. For example, when a heavier cam is being stabilized on a rolling right, it will take a lot more torque to get it to roll left during stabilization...much more inertia with a heavier cam (5D3) compared to a GH2. The Zen makes much faster angle adjustments compared to standard servo driven gimbals. This is where torque comes in to play.

As a test, hold a 5D2 in your hand and quickly roll it left and right. Now hold a Nex7 or a GH2 in your hand and do the same...you'll feel the difference in the torque needed to quickly roll left/right.

Only one way to find out!
You have very good points and I agree with everything you say. I guess someone has to just go ahead and try it! I wish I had a Z15 in front of me, to take a look and see how it really works. Ever since Hexa pointed out, that it makes more sense to take it apart and replace certain parts with bigger once, instead of "cutting" it apart, I am probably gonna get one and try that. I am not sure why, but it really bothers me that you cannot use bigger lenses?! I mean, I am no expert in cinematography, but I see the difference between taking a Portrait with a 24mm lens, compared to a 200mm lens! It just doesn't look the same?! When you see aerial footage of a pro, you can tell that they are far away and zoom in. Whereas the amateur, is using a shorter lens and has to be practically in front of the object. Take a look at this video. You see some footage of what I am talking about starting at 2:08...

The Schiebel CAMCOPTER® S-100 / Cineflex Integration with Brain Farm and SnapRoll (3 min 1 sec)


I know, you cannot really compare this to a S800... I just like to hear what others think and they have the same "need" for a longer lens?!

thanks,

G
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Old Jan 13, 2013, 08:43 AM
United States, MI, Goodrich
Joined Mar 2004
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Aerial Photography you want wide angle. To zoom in you just fly closer, thus the advantage we have to full size aircraft. Also, as you zoom in you will find stabilization becomes very difficult. Any movement when zoomed in is amplified by "x" amount.

The Schiebel was at NAB show and its a massive awesome machine to say the least.
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Old Jan 13, 2013, 08:48 AM
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Austria, Niederösterr., Eggenburg
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The Schiebel Camcopter is a different league. Also they have to zoom in, since they cannot come close.
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Old Jan 13, 2013, 09:00 AM
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Joined Feb 2008
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Quote:
Originally Posted by DorianJ View Post
I think the main question is torque handling, will the motors be able to make fast angle adjustments when stabilizing the added weight of a heavier camera. Kind of like with spinning a bigger prop on smaller BL motors...the motors will not have the torque to make fast enough adjustments therefore the multi will not be as stable compared to running smaller props which will need less torque to spin and will be able to make fast adjustment for a more stable flight. Worse case is you won't experience the great stabilization using a heavier cam compared to using the cams the Zen was designed for.

Even if the heavier cam is perfectly balanced on the gimbal, there is the issue of inertia. For example, when a heavier cam is being stabilized on a rolling right, it will take a lot more torque to get it to roll left during stabilization...much more inertia with a heavier cam (5D3) compared to a GH2. The Zen makes much faster angle adjustments compared to standard servo driven gimbals. This is where torque comes in to play.

As a test, hold a 5D2 in your hand and quickly roll it left and right. Now hold a Nex7 or a GH2 in your hand and do the same...you'll feel the difference in the torque needed to quickly roll left/right.

Only one way to find out!
Hi Dorian,

What you say is indeed the likely outcome but not quite for the reasons you say.

Some theory...
A "perfectly" balanced gimbal theoretically will not want to move off target under any kind of disturbance accelerations. Having the CG exactly coincident with the pivot axes removes any moment arm, thus the gimbal becomes completely immune to the 3-DOF of translational accels, and its own intrinsic MOI about the pivot axes will make the gimbal naturally want to resist from the 3-DOF of rotational accels. Thus, the theoretical perfect balanced gimbal will present no torque demand on the motors unless the operator purposely slews it out of position in inertial space (In earth's frame of reference).

Some practice...
1) "Perfect" is a tricky word. Our gimbal balance instruments will achieve a residual imbalance of less than 0.1 g-cm. Even at our levels there are undesired responses to translational disturbances (albeit these gimbals are subject to huge g-forces). This realm is perhaps 50 to 100 times what is achievable by the hand techniques used on this thread. At the balance levels achievable by hand, torque is indeed required to resist the moments caused by translational disturbance accels. Note that rotational disturbance accels are still rendered unimportant.
2) Friction. The theoretical perfect balanced gimbal has friction in the pivots. This friction transfers rotational DOF disturbances through to the gimbal The intrinsic MOI will still resist responding to this but the friction will attempt to move the gimbal off target. Thus the motor will have to overcome the friction to hold target in inertial space.
3) Wires and cables between the air frame and successive axes. Wires and cables impart more friction, add spring forces, and add hysteresis into the system. As noted above, these transfer mechanisms allow rotational disturbances through. But once again the motors only have to overcome these unwanted transfer forces, not the entire MOI of any particular axis.


So yes, in practice, the motors may struggle against the "perfect" balanced larger gimbal load, but mainly because the "perfect" was not achieved. The added loads from friction, wire, cables, etc, present fairly light loads if routing was thought through properly. All this theory and practice describes a situation where the operator wants to hold on target. In this scenario even in your roll example the added MOI does not hurt, it only helps. Here's why. As the air frame rolls the larger MOI camera tries "harder" (through no other mechanism other than physics) to maintain its position and remain fixed to target. It never actually has to move. The gimbal's torquer motors only have to "give up" and allow the relative position between the gimbal and air frame to "slip" Not much torque is required for this to happen.

The real issue is when the operator purposely attempt to slew off target and not enough torque is available to overcome the larger MOI (I consistently call it MOI and not inertia which is simply a surrogate term for mass). That, and the aforementioned high residual imbalance will make the gimbal act as you say.

Sorry for the long-winded response, I hope to help advance the ball by sharing knowledge.

Cheers,
Dan
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Last edited by otlski; Jan 13, 2013 at 09:21 AM.
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Old Jan 13, 2013, 09:09 AM
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Joined Jan 2013
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The Cineflex Elite on that Schiebel uses tracking software, it doesn't just adjust for the motion of the aircraft but it can also analyze the image to adjust the direction of the lens. Another difference is that it always knows what coordinate it is supposed to be pointing at rather than just measuring the output from the gyros. I don't think your WKM can do that
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