Photohigher skyline rsgs

jes1111

Active Member
I'll do that after I have flown it as It may need more work. I don't like the idea of a friction brake to stop the jitter, that is the opposite way that this needs to work. Mass balance would be useless in that scenario.
Yep - artificially-induced lag is a poor solution - kinda like "curing" a hyper-active child by strapping a weight-belt around their waist ;)

If your new wiring harness works out, it should be named the "Rowland Rig" - as in: "Yeah, I've got a Skyjib/Cinestar setup - with the Rowland Rig, of course" :)
 
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jes1111

Active Member
Hi, about the PID discussion: the velocity gain was acting as a DAMPENING function. So it's not a PI but a PD regulation as you describe it.
Photohigher have simplified the software interface to avoid user problem using the skyline.
Since they're being "loose" with the terminology anyway, it's still likely that their "Velocity Gain" was the I term (or related to it) - having "I" too high would cause an over-nervous system - lowering it would, indeed, dampen the system. It's possible that for the UI they were actually inverting the Velocity Gain value - our problem is speculating about what's going on under the hood when all we can see are the "dumbed down" sliders/labels the UI designer gave us. I'd be very surprised if it is a PD controller - they are rather specialised (usually used when an overshoot error is irreversible or impossible and therefore must be avoided at all costs - like when mixing chemicals or positioning two solid bodies against each other). Who knows? (I just hope that PH do! :))
 

DennyR

Active Member
Yep - artificially-induced lag is a poor solution - kinda like "curing" a hyper-active child by strapping a weight-belt around their waist ;)

If your new wiring harness works out, it should be named the "Rowland Rig" - as in: "Yeah, I've got a Skyjib/Cinestar setup - with the Rowland Rig, of course" :)

I got this as a play thing for the 550D and a test base for a new adventure into the use of 4 voice coil driven inner axis system.
 


ChrisViperM

Active Member
I just imagine how the "development team" from Photohigher are reading the statemens from jes1111 and Denny with a dropped down jaw and think how much they would have to offer to get them on board to solve their mess....:nevreness:

You guys got my deepest respect...for your knowledge and especially for your patience....I would have gone through the roof already

Chris
 


PairAir

Member

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jes1111

Active Member
I just imagine how the "development team" from Photohigher are reading the statemens from jes1111 and Denny with a dropped down jaw and think how much they would have to offer to get them on board to solve their mess....:nevreness:

You guys got my deepest respect...for your knowledge and especially for your patience....I would have gone through the roof already

Chris
Well certainly they should have experienced and knowledgeable beta testers (like Denny, though I'm sure they couldn't pay him enough). Not sure they need a pompous pedant like me, though ;) - I'm like Taub and Thirteen in "House" - just throw every possible diagnosis on the table in the hope that one of them is right :D But then I'm also like House himself - not interested in the patient, I just enjoy the puzzle.
 

tppeng

Member
I just imagine how the "development team" from Photohigher are reading the statemens from jes1111 and Denny with a dropped down jaw and think how much they would have to offer to get them on board to solve their mess....:nevreness:

You guys got my deepest respect...for your knowledge and especially for your patience....I would have gone through the roof already

Chris

+2
Salute!
 

DennyR

Active Member
Sorry for my ignorance, but can you use the output from the Skyline and drive this kind of motor via, say, a driver like this [AThttp://www.youtube.com/watch?v=glMvAtLEaxkTACH=CONFIG]7345[/ATTACH]

My own developments are centered around the use of much smaller and lighter components that use Piezoelectric transducers which come in many shapes and sizes the motors are a based on the these PCB ones. The whole idea is that the framework is built around 3 PCB boards that will have a PWM input and the MPU 6000 built into it. A tiny GoPro size mount that has 5 axis of very accurate resolution and vibration attenuation. rls=en&q=piezoelectric+motors&ie=UTF-8&oe=UTFhttp://www.youtube.com/watch?v=glMvAtLEaxk
http://www.youtube.com/watch?v=Qfb8Zaj1jT4&feature=player_embedded
http://www.youtube.com/watch?v=VbTUsluY2xU&feature=related

As the GoPro is nothing more than a PCB with a lens then that can also be designed into the system.
 
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Hi DennyR,

Be carefull with piezoelectric actuator, the linearity and backlash is huge when you are not working in closed loop.
edit: this is for high accuracy and repetability.

The velocity of the piezoelectric actuator isn't very fast also for high precision one like nanomotion (Ok you will surely not using nanomotion but...)
 
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PairAir

Member
My own developments are centered around the use of much smaller and lighter components that use Piezoelectric transducers which come in many shapes and sizes the motors are a based on the these PCB ones. The whole idea is that the framework is built around 3 PCB boards that will have a PWM input and the MPU 6000 built into it. A tiny GoPro size mount that has 5 axis of very accurate resolution and vibration attenuation. rls=en&q=piezoelectric+motors&ie=UTF-8&oe=UTFhttp://www.youtube.com/watch?v=glMvAtLEaxk
http://www.youtube.com/watch?v=Qfb8Zaj1jT4&feature=player_embedded
http://www.youtube.com/watch?v=VbTUsluY2xU&feature=related

As the GoPro is nothing more than a PCB with a lens then that can also be designed into the system.

Hmm, you lost me there I'm afraid... But very interesting
 

Hi,

about the PID discussion: the velocity gain was acting as a DAMPENING function. So it's not a PI but a PD regulation as you describe it.
Photohigher have simplified the software interface to avoid user problem using the skyline.

About using 2 skylnes: one of my customer have used this solution succesfully for a shooting in mongolia. As you have seen, using only one servo avoid most of the jitter problem.
He have placed both skyline on a cinestar gimbal.

Best regards,
Cédric

If 2 skylines can be solution then we should not be byuing the other one as Chris said but we should be given one for free as we paid for 3 axes stab and we have one axe stab and PH should give us another for free but I think that even 2 would not solve the problem of tilt !
 

DennyR

Active Member
We are not out of the woods yet as this thing did not cut the mustard once it was in the air. Jitter is back again.
Starting to look more like an algorithm problem or they left off the board some filtering components.

As it is a cross axis problem it could be quite a serious nut to crack. Time cop had a similar problem with his 32 bit board. Great for what it was designed to do but as a camera imu no way without some serious work. PID algorithms vary enormously as do sensor fusion algorithms. As it is not open source we are now in their hands once again. They need to get rid of that autotune crap so we can see what is going on. Enough time has been wasted.
 



hdj912

Member
Since the last firmware no response anymore from PH, time to let us know what they are doing or what we can expect.
 

DennyR

Active Member
Since the last firmware no response anymore from PH, time to let us know what they are doing or what we can expect.
I agree this product does not fulfill the legal requirement of being fit for purpose. A mistake like this could put someone out of business.
Hope you bought with a credit card.

At least last week showed that Vodaphone Maclaren found a Eureka moment in F1. (At Last).
 

The good thing is that PH are ready to reimburse the money to all those who are not happy with the product ( and nobody is ) and do not want to wait anymore .
This is what I understood 1001 copters , is that right 1001 copters ?
Do the still sell Skyline or they stopped the sale ?

I think that PH should post here what they are doing and what their intentions are ?
 

jes1111

Active Member
We are not out of the woods yet as this thing did not cut the mustard once it was in the air. Jitter is back again.
Starting to look more like an algorithm problem or they left off the board some filtering components.

As it is a cross axis problem it could be quite a serious nut to crack.
My guess at the moment (having never even seen one of these but going only by anecdotal evidence presented here and an instinct for diagnosis) is that it's multiple problems that are masking and complicating each other:
- cross-axis "pollution" in the algorithm (the oddest problem since evidently it didn't appear in PH's in-house testing),
- excessive production of and/or sensitivity to EMI (for which PH offered an apparently ineffective solution),
- insufficient "bandwidth" to cope with third-party components whose "sum of errors" falls outside the (apparently) narrow range tested by PH (possibly the most unforgivable error).

Obviously separating these causes and effects requires a methodical approach, some fancy bench-test equipment and, above all, access to the circuit diagrams and source code. So we can flail around in the dark all we want, but only PH themselves can solve this. (Kinda underlines the advantages of open source, doesn't it?)

The most worrying fact is that PH (and some third-parties) tested this (and showed videos) and judged it to be market-ready.
 

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