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Old Jan 23, 2013, 04:20 PM
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United States, IN, Indianapolis
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One question I have about these type of controls is, what happens when the gimbal or motor stalls for some reason? There is no positional feedback to know where it is, it is all relative.

Say it starts up normally, that motor/gimbal positions are 0, or center, well call that the datum. What happens when inertia overcomes torque, when you are flying fast and stop fast, and the gimbal wants to swing causing inertia to overcome the torque and the motor "skips"? Since its a relative positioning system it would now "center" at a different position than it started.

I am assuming this is why you stress that it must be well balanced, so as to minimize these effects.

What happens when you have a cam like an SLR, where you position the lens to be coincident with the axis, but the mass is deviant?

It would not be difficult to add positional feedback via a pot and make it a full closed loop servo system.
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Old Jan 23, 2013, 05:13 PM
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Quote:
Originally Posted by KKUSA View Post
One question I have about these type of controls is, what happens when the gimbal or motor stalls for some reason? There is no positional feedback to know where it is, it is all relative.

Say it starts up normally, that motor/gimbal positions are 0, or center, well call that the datum. What happens when inertia overcomes torque, when you are flying fast and stop fast, and the gimbal wants to swing causing inertia to overcome the torque and the motor "skips"? Since its a relative positioning system it would now "center" at a different position than it started.

I am assuming this is why you stress that it must be well balanced, so as to minimize these effects.

What happens when you have a cam like an SLR, where you position the lens to be coincident with the axis, but the mass is deviant?

It would not be difficult to add positional feedback via a pot and make it a full closed loop servo system.
Fabulous questions.
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Old Jan 23, 2013, 05:21 PM
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Don't know about position feedback (good idea!), but of course the Zen is sold configured for specific camera and lens combos. And nothing close to SLR size.

-Max
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Old Jan 23, 2013, 05:29 PM
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Another question if you look at ~1:40
How does the controller know that it's not level?

Home Made Brushless Direct Drive Gimbal (6 min 4 sec)


I guess the "trick" is to build a setup where motors can handle the inertia without skipping. And a firmware which "knows" that the motor just stalled.

I'm pretty sure there will be some teething problems when going for bigger heavier/cameras. But I'm also sure there will a lot of testing and checking going on in the next few month...

We can only get better.
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Old Jan 23, 2013, 05:43 PM
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If size matters...
I find the Photohigher Hero gimbal very attractive:



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Old Jan 23, 2013, 05:53 PM
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The MPU6050 fixed to camera is serving as the encoder/feedback. So in essence it is a closed loop system. But its the "Simple" version.

Of course there are other ways to do it - like Maxon motors, external optical encoders or other types of encoder that will give you resolutions and accuracies down to 1/10īs of a degree or lower. That is already beeing worked on by Autoquad team members, but it will be more complicated to build and more expensive.

If you stall the gimbal, it will go a few steps back and then try again to reach the desired angle. You wont burn motors or anything like that.
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Old Jan 23, 2013, 05:55 PM
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Quote:
Originally Posted by kinderkram View Post
Another question if you look at ~1:40
How does the controller know that it's not level?

https://www.youtube.com/watch?v=9_8Kb_fXRrU

I guess the "trick" is to build a setup where motors can handle the inertia without skipping. And a firmware which "knows" that the motor just stalled.

I'm pretty sure there will be some teething problems when going for bigger heavier/cameras. But I'm also sure there will a lot of testing and checking going on in the next few month...

We can only get better.
Absolutely!!!

One inexpensive, compact way to provide feedback would be a single analog hall effect sensor and magnet. It wouldnt need to be 100% accurate, nor would it need to provide absolute position, but it could tell if it is not level, or deviated from the datum. Then there could be an automatic re-centering method.

A single hall, detecting rotor magnets could even be employed, but it would be a little more difficult.

I personally think that if this is to be used on more than just a few specific cameras, some positional feedback is going to be necessary.

A simple pot could be easily implemented as well. Using a decent quality pot we could have very good positional accuracy.
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Old Jan 23, 2013, 06:07 PM
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Originally Posted by kinderkram View Post
If size matters...
I find the Photohigher Hero gimbal very attractive:



Speachless...
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Old Jan 23, 2013, 06:14 PM
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Speachless...
You got it. That's what these bling-bling gimbals are made for. To make the client speechless so he will pay any rate. Would be good though if it works technically too.
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Old Jan 23, 2013, 07:25 PM
DiaLFonZo - UAV/Drone
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Originally Posted by ~>Miha<~ View Post
You got it. That's what these bling-bling gimbals are made for. To make the client speechless so he will pay any rate. Would be good though if it works technically too.
If i had something like that. i would just put in on a shelf and look at it.. HaHa..
(but i do see the point, i am just in love with CF)
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Old Jan 23, 2013, 07:49 PM
Begin with end in mind...
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Eagle Lake, Minnesota
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Carbon is attractive but function is more important. I believe in simplicity and things appear to be on the right track here I have no idea of the cost but IMO that carbon gimbal is for folks with a ton of "expendable" income. It will not be inexpensive....

Mike
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Old Jan 23, 2013, 08:11 PM
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Carbon is attractive but function is more important.
Couldn't agree more: Function is everything!

But those bling-bling manufacturers don't earn their millions with us who earn money doing AP/AV. It's for those noobs who think they could earn money by just buying overpriced stuff (they'll never break even...). And for the very few pros who use it to show off and justify rates or those who get sponsored by the manufacturers.

My stuff looks like post-apocalyptic Mad Max design, but it works. Anything else is irrelevant and I won't pay for. I hope this projects goes for functionality too.
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Old Jan 23, 2013, 08:12 PM
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impatiently waiting!
Me too
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Old Jan 23, 2013, 08:31 PM
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Originally Posted by ~>Miha<~ View Post
I hope this projects goes for functionality too.
You can bet!

This project already focusses on simplicity combined with functionality.
Doesn't mean it has to be ugly like the nite...

Good thing is the poor man can get as stable footage as the rich man.
Mission accomplished.
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Old Jan 23, 2013, 10:31 PM
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subscribe and hope to pre order the DSLR version soon.
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