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Old Apr 29, 2012, 05:44 PM
John
United States, WA, Mason
Joined Apr 2011
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Quote:
Originally Posted by Adidas4275 View Post
john i love the location..... and you have more guts that i do..... i am a chicken to fly over water


are you flying LOS or FPV? and is that a Flamewheel that you are flying?


Askman's gimbal does a great job, I still need some tuning, but it works well
That is just LOS. The machine is a "RcCarbon" Y-6. Because of the DJI twitching, like I said last time, I have had the gimbal output disconnected. But I found that if I disconnect the GPS that it doesn't have the twitching problem. So this video was with the Gimabal output connected again, but the GPS disconnected. Even without the twitch, it is no match for keeping up with Askmans. I just have a hard time spending more money. Especially when I have only done 1 paid job, and the rest has just been for me playing around. It's just when I see the smoothness from you and more when I see the split screen stuff from Gary, where I can see how much his machine is tilting and rolling around and at the same time see how stable the output video is. I WANT THAT! -- JOHN
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Old Apr 29, 2012, 05:58 PM
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GGoodrum's Avatar
South Orange County, CA
Joined Mar 2003
8,001 Posts
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Originally Posted by Wingbreaker View Post
I'm sure quality of gimbal and servos has a lot to do with it. I doubt ill get the performance with hobby king servos and this little gimbal that they get with the ask man setup. if someone can I'd like to see. I'm not seeing many links to great video with just the naza controller, just got me wondering. The other thing "I'm buying up" to is a better camera on the platform. The go pro is nice but it is limited. an nex5n is a really good sensor.
There are two issues with getting great video using the Naza's gimbal outputs. The main one is that the gimbal servo output PWM rate is really low, like 50-100Hz. They did this so that it could be used with inexpensive gimbals that use analog servos. High-end, high resolution digital servos, like the MKS variants, need to have this update rate much higher, like 400-500Hz, in order to operate as smoothly as possible. With Naza's outputs, you just can't seem to get rid of the roughness you see with small movements. This can show up in the video as a "bounce". The second problem with the Naza's gimbal outputs is that they limit the travel range to 90 degrees. No idea why they thought this was a good thing.

In order to completely get rid of this jitter/bounce, we had to do three things. First, we had to increase the belt drive ratio to 2.5:1. That help quite a bit, but what we also had to do was go to the MKS servos. The reason for the latter is that after an exhaustive and expensive series of tests, it turns out that in addition to having 12 bits of resolution in the servo electronics, what is also needed is a really low deadband timing rating. This characteristic alone seems to have the greatest impact on just how smooth you can get this setup. Otherwise excellent servos, like various hi-res models from Savox, JR, Hitec, and Futaba, simply don't work as well in this application because they had deadband values around .002ms. The MKS BLS950 has a deadband value of only .0008ms. The only other servo I've found that is similar in this regard is the $200 BLS series from Futaba. Finally, the last thing we need to do is use a gimbal controller that lets us set the PWM rate to 500Hz. I've done tests to keep dropping this value down, watching what happens, and as soon as I get below about 300Hz, the jitter/bounce is back..

There are other flight computer models that have fast and/or settable PW output rates. The HoverFly Pro board is one, as is the XA FC/AHRS combo. I've been using the latter as a standalone gimbal controller for this exact reason. In the companion PC app you can set the "Output Period" to a value of 20ms, down to 2ms. This corresponds to an output rate of 50Hz to 500Hz, respectively.

You could increase the belt drive ratio to get more smoothness, but doing that comes at cost. The introduces a lag in responding to large platform corrections. this causes unwanted movement in the video. The goal here, however is to not lose the important platform independence feature we have now with this setup.

Getting back to gimbal controllers, we are looking at using timecop's nifty little Naze32 board as a dedicated gimbal controller. We have it working quite well, right now, but we have a weird twitching problem, due to bad accelerometer data, but we are looking at various filtering schemes to try to fix this. Otherwise, it works amazingly well. We can set the travel to full amount the servo can handle, dial the gains in perfectly, and set the PWM rate to 500Hz. The XA FC/AHRS works almost as well, but the gains are adjusted via a slider, with values that range from 0-100. to get the gains set perfect, we really need a bit more granularity. The Naze32 firmware lets do much finer "tweaking" of the gains values.

The following video is very close, but the gains are just a tiny bit off, so you can see some slight "twisting" in the roll axis, during corrections. In strong wind gusts like this, the WK-M makes some aggressive corrections in order to hold position. This was using the XA FC/AHRS as a standalone controller, and I have gotten the gains more closely set with Naze32 board.

AG550-NX 2-Axis NEX-5N Gimbal Test-01r.mov (4 min 45 sec)


Anyway, to get true platform independence and smooth video, you have to have this "perfect storm" combination of low deadband servos, a belt drive ratio of 2.5:1, a fast servo output PWM rate of 400-500Hz and the ability to really fine-tune the gain settings.

The exception to all this, is the new series of camcorders from Sony that have the "balanced OIS function, where the whole lens block moves around. What this does is opens up the "perfect storm" parameters because the camera itself can remove a lot of the jitter/bounce. It appears, however, that this only works in the tilt axis, for the most part. I need to test this further, but I'm hopeful that it will at least allow the use of some other servos in the roll axis, or maybe a relaxation of the belt drive ratio a bit. In the tilt axis, we can do a lot more. In the vide I did yesterday, with a temporary yoke setup, the setup was really nose heavy, and the camera literally would fall straight down unles power was applied, and the servo was holding it in place. This cause some pretty severe lens bounce every time I tried moving the tilt position. I compounded that by changing to tilt belt drive ration to 1.3:1, from 2.5:1.Anyway, as you can see in the video, the camera eliminates all but the very worst of these bounces.

AG550-PJ 2-Axis Gimbal Test-01.mov (3 min 6 sec)


In any case, with this particular series of cameras, our "perfect storm" scenario can be scaled back to "partly cloudy". Well, at least for the tilt axis. the jury is still out for how far away from the "standard" configuration we will be able to go.

-- Gary
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Old Apr 29, 2012, 06:20 PM
manual flying apologist
Adidas4275's Avatar
United States, CA, Fresno
Joined Mar 2011
6,944 Posts
Quote:
Originally Posted by digitalCAM View Post
That is just LOS. The machine is a "RcCarbon" Y-6. Because of the DJI twitching, like I said last time, I have had the gimbal output disconnected. But I found that if I disconnect the GPS that it doesn't have the twitching problem. So this video was with the Gimabal output connected again, but the GPS disconnected. Even without the twitch, it is no match for keeping up with Askmans. I just have a hard time spending more money. Especially when I have only done 1 paid job, and the rest has just been for me playing around. It's just when I see the smoothness from you and more when I see the split screen stuff from Gary, where I can see how much his machine is tilting and rolling around and at the same time see how stable the output video is. I WANT THAT! -- JOHN
cool. I really like my RC-Carbon Y-6 cool were both flying one.... they seem endangered recently

I sold my 2nd Rc-Carbon frame just too much $$ so i totally understand.

too bad that WKM twitches like that. I am surprised I have not heard more about it. Most people rave about it. I love the smoothness of gyro only flight


well your 1 paid job is ahead of me


save up for a little bit and pick up askmans gimbal, the only thing I have seen that is better is the Cinestar gimbal.... $1k
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Old Apr 29, 2012, 07:22 PM
Video Juggernaut
Wingbreaker's Avatar
FL
Joined Nov 2003
2,652 Posts
Quote:
Originally Posted by GGoodrum View Post
There are two issues with getting great video using the Naza's gimbal outputs. The main one is that the gimbal servo output PWM rate is really low, like 50-100Hz. They did this so that it could be used with inexpensive gimbals that use analog servos. High-end, high resolution digital servos, like the MKS variants, need to have this update rate much higher, like 400-500Hz, in order to operate as smoothly as possible. With Naza's outputs, you just can't seem to get rid of the roughness you see with small movements. This can show up in the video as a "bounce". The second problem with the Naza's gimbal outputs is that they limit the travel range to 90 degrees. No idea why they thought this was a good thing.

In order to completely get rid of this jitter/bounce, we had to do three things. First, we had to increase the belt drive ratio to 2.5:1. That help quite a bit, but what we also had to do was go to the MKS servos. The reason for the latter is that after an exhaustive and expensive series of tests, it turns out that in addition to having 12 bits of resolution in the servo electronics, what is also needed is a really low deadband timing rating. This characteristic alone seems to have the greatest impact on just how smooth you can get this setup. Otherwise excellent servos, like various hi-res models from Savox, JR, Hitec, and Futaba, simply don't work as well in this application because they had deadband values around .002ms. The MKS BLS950 has a deadband value of only .0008ms. The only other servo I've found that is similar in this regard is the $200 BLS series from Futaba. Finally, the last thing we need to do is use a gimbal controller that lets us set the PWM rate to 500Hz. I've done tests to keep dropping this value down, watching what happens, and as soon as I get below about 300Hz, the jitter/bounce is back..

There are other flight computer models that have fast and/or settable PW output rates. The HoverFly Pro board is one, as is the XA FC/AHRS combo. I've been using the latter as a standalone gimbal controller for this exact reason. In the companion PC app you can set the "Output Period" to a value of 20ms, down to 2ms. This corresponds to an output rate of 50Hz to 500Hz, respectively.

You could increase the belt drive ratio to get more smoothness, but doing that comes at cost. The introduces a lag in responding to large platform corrections. this causes unwanted movement in the video. The goal here, however is to not lose the important platform independence feature we have now with this setup.

Getting back to gimbal controllers, we are looking at using timecop's nifty little Naze32 board as a dedicated gimbal controller. We have it working quite well, right now, but we have a weird twitching problem, due to bad accelerometer data, but we are looking at various filtering schemes to try to fix this. Otherwise, it works amazingly well. We can set the travel to full amount the servo can handle, dial the gains in perfectly, and set the PWM rate to 500Hz. The XA FC/AHRS works almost as well, but the gains are adjusted via a slider, with values that range from 0-100. to get the gains set perfect, we really need a bit more granularity. The Naze32 firmware lets do much finer "tweaking" of the gains values.

The following video is very close, but the gains are just a tiny bit off, so you can see some slight "twisting" in the roll axis, during corrections. In strong wind gusts like this, the WK-M makes some aggressive corrections in order to hold position. This was using the XA FC/AHRS as a standalone controller, and I have gotten the gains more closely set with Naze32 board.

http://youtu.be/0tkdYIV-4JY

Anyway, to get true platform independence and smooth video, you have to have this "perfect storm" combination of low deadband servos, a belt drive ratio of 2.5:1, a fast servo output PWM rate of 400-500Hz and the ability to really fine-tune the gain settings.

The exception to all this, is the new series of camcorders from Sony that have the "balanced OIS function, where the whole lens block moves around. What this does is opens up the "perfect storm" parameters because the camera itself can remove a lot of the jitter/bounce. It appears, however, that this only works in the tilt axis, for the most part. I need to test this further, but I'm hopeful that it will at least allow the use of some other servos in the roll axis, or maybe a relaxation of the belt drive ratio a bit. In the tilt axis, we can do a lot more. In the vide I did yesterday, with a temporary yoke setup, the setup was really nose heavy, and the camera literally would fall straight down unles power was applied, and the servo was holding it in place. This cause some pretty severe lens bounce every time I tried moving the tilt position. I compounded that by changing to tilt belt drive ration to 1.3:1, from 2.5:1.Anyway, as you can see in the video, the camera eliminates all but the very worst of these bounces.

http://youtu.be/GZg96OKr6B4

In any case, with this particular series of cameras, our "perfect storm" scenario can be scaled back to "partly cloudy". Well, at least for the tilt axis. the jury is still out for how far away from the "standard" configuration we will be able to go.

-- Gary

Wow, thanks for the input.

So what would you recommend I use for gimbal control if I purchase the askman gimbal?

Quote:
Today 10:37 PM
askman naza is usable. it gives decent result, (I've been using it and it is good enough for testing) but we don't get maximum performance from naza. that is what we are trying to achieve with naze32 once firmware is fixed. naza could be fixed, but they won't so we are left looking for alternative.


adidas. you got vibration problem totally licked. great job. good result hardmounted .

good quality servo is ciritical for good performance. so far, mks has been the only ones upto it. in my setup, I am running mks brushless on the roll and hyperion tilt with expanded servo that is not stabilized. I fly smoothly and in forward flight, the video looks great. this allows me to have full 90 deg tilt. it does not work as well for heavy wind hovering though. for me, it is easy to swap out the gimbal with brushless on the tilt as well for stabilization.
Askman, do you have video online that shows your gimbal using the naza controller?

So i am assuming some of my problems on my little x486 flame gear gimbal is a digital servo? or should I give up on this and get one of yours for the f450?

naza x486 flamegear f450 test (5 min 43 sec)


Oh what about the WK-M? Thoughts on that controller? I think they are giving away free f450 arf with a purchase of the WK-M
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Last edited by Wingbreaker; Apr 29, 2012 at 08:00 PM.
Old Apr 29, 2012, 11:45 PM
Registered User
Hawaii
Joined Feb 2003
5,952 Posts
>> I really like my RC-Carbon Y-6 cool were both flying one.... they seem endangered recently <<

Let me add to the gene pool. I am still flying mine.
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Old Apr 29, 2012, 11:52 PM
Registered User
United States, CA, Ventura
Joined Aug 2007
684 Posts
@adidas, so the bounce I saw in your video was lens bounce? were you shooting with the 18-55? I just can't get mine licked, especially in high winds... Just curious, and great job!
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Old Apr 29, 2012, 11:54 PM
manual flying apologist
Adidas4275's Avatar
United States, CA, Fresno
Joined Mar 2011
6,944 Posts
yeah 18-55

not sure if it was lens or from the flight controller gain settings.

I just chopped off 1 1/2" from each arm on my RC carbon frame (with the wires still inside.......... )

so i think my MTM distance was way to big cuasing my Flight controller to work too hard to keep yaw and was inducing some stepping....

so tomorrow or wednesday I will add some foam under the lens.... and with the shorter arms well will see if i can kick it

your not the only one
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Old Apr 30, 2012, 12:51 AM
Gravity is a cruel mistress...
Blucross's Avatar
United States, FL, Orlando
Joined Mar 2011
724 Posts
I'm loving this thread. Add me to the list with my RC-Carbon Y6 (Thanks Adidas), and soon to be ordered AG550NX Gimbal. I have a Wookong-M and a CopterControl. For this build I think the CopterControl is better suited since I can set a high PW for the gimbal output which will benefit the MKS servos, and the CC doesn't have the roll twitching with GPS enabled like the Wookong does.

I'll be using it with my Hacked GH1, I am a fan of prime lenses, and I use Canon glass. The largest lens I would use though would be a 50mm size Canon FD lens. Smallest would probably be the 14mm Lumix Pancake. I'm stoked about finally having a gimbal that can sling a GH1 and do it well.
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Old Apr 30, 2012, 12:54 AM
SMILE you're being recorded :)
Velociraptor73's Avatar
Joined Apr 2010
755 Posts
Quote:
Originally Posted by GGoodrum View Post
I'm using a single 4s-5800 right now, but I've also used a pair of 4s-3300s in parallel. I would stay away from 3s. Spend the extra $50 and get a good 4s-5000 pack (40C or higher...). Also, use the 10x5 Graupners.

-- Gary
Hi Gary, any particular reason why you swapped two 3300 in parallel for a single 5800 ?

And why do you recommend 40C or higher?
Isn't 25C enough for the F550 setup?!

Regarding 3S, I imagine they are probably more suitable for light weight flights likes the unloaded ones I'm doing while testing my new F550, but there is any other reason for avoiding them if not for the heavier weight the 4S can fly with?
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Last edited by Velociraptor73; Apr 30, 2012 at 01:01 AM.
Old Apr 30, 2012, 12:54 AM
manual flying apologist
Adidas4275's Avatar
United States, CA, Fresno
Joined Mar 2011
6,944 Posts
Quote:
Originally Posted by Blucross View Post
I'm loving this thread. Add me to the list with my RC-Carbon Y6 (Thanks Adidas), and soon to be ordered AG550NX Gimbal. I have a Wookong-M and a CopterControl. For this build I think the CopterControl is better suited since I can set a high PW for the gimbal output which will benefit the MKS servos, and the CC doesn't have the roll twitching with GPS enabled like the Wookong does.

I'll be using it with my Hacked GH1, I am a fan of prime lenses, and I use Canon glass. The largest lens I would use though would be a 50mm size Canon FD lens. Smallest would probably be the 14mm Lumix Pancake. I'm stoked about finally having a gimbal that can sling a GH1 and do it well.

that will be nice....

i want to try a CC board

i dont think the naza is what i am looking for
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Old Apr 30, 2012, 01:02 AM
Gravity is a cruel mistress...
Blucross's Avatar
United States, FL, Orlando
Joined Mar 2011
724 Posts
I would say the Naza is better suited for beginners, FPV and AP hobbyists.

I love mine, but so far I found it is better in manual mode for sport flying and FPV, and the AH is good for when you want some nice slow stable AP or FPV. If they up the PW on the gimbal outputs in a firmware update, I would say it would step up into a new class and would pair nicely with the AG550NX.
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Old Apr 30, 2012, 01:03 AM
Registered User
GGoodrum's Avatar
South Orange County, CA
Joined Mar 2003
8,001 Posts
Quote:
Originally Posted by Blucross View Post
I'm loving this thread. Add me to the list with my RC-Carbon Y6 (Thanks Adidas), and soon to be ordered AG550NX Gimbal. I have a Wookong-M and a CopterControl. For this build I think the CopterControl is better suited since I can set a high PW for the gimbal output which will benefit the MKS servos, and the CC doesn't have the roll twitching with GPS enabled like the Wookong does.

I'll be using it with my Hacked GH1, I am a fan of prime lenses, and I use Canon glass. The largest lens I would use though would be a 50mm size Canon FD lens. Smallest would probably be the 14mm Lumix Pancake. I'm stoked about finally having a gimbal that can sling a GH1 and do it well.
Yes, that should be a great setup. The video out of those hacked GH1/2s and GF3s is amazing.

-- Gary
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Old Apr 30, 2012, 08:19 AM
Video Juggernaut
Wingbreaker's Avatar
FL
Joined Nov 2003
2,652 Posts
Quote:
Originally Posted by Blucross View Post
I'm loving this thread. Add me to the list with my RC-Carbon Y6 (Thanks Adidas), and soon to be ordered AG550NX Gimbal. I have a Wookong-M and a CopterControl. For this build I think the CopterControl is better suited since I can set a high PW for the gimbal output which will benefit the MKS servos, and the CC doesn't have the roll twitching with GPS enabled like the Wookong does.

I'll be using it with my Hacked GH1, I am a fan of prime lenses, and I use Canon glass. The largest lens I would use though would be a 50mm size Canon FD lens. Smallest would probably be the 14mm Lumix Pancake. I'm stoked about finally having a gimbal that can sling a GH1 and do it well.
Do you know if any of the smaller panasonic mirrorless cameras sport the same sensor and hacking abilities that the gh series have? the 2k hack on that cam is really nice but I don't know if it is worth the extra weight as most video goes straight to web and 2k is really only necessary for color correction and large screen formats nowadays. However, that has been disproved too since the use of the 7D and 5D in movies like Iron Man, Black Swan and Red Tails
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Old Apr 30, 2012, 08:40 AM
Gravity is a cruel mistress...
Blucross's Avatar
United States, FL, Orlando
Joined Mar 2011
724 Posts
Actually, yeah. The GF3 is now hackable and is much lighter than the GH series.
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Old Apr 30, 2012, 09:07 AM
Video Juggernaut
Wingbreaker's Avatar
FL
Joined Nov 2003
2,652 Posts
Quote:
Originally Posted by Blucross View Post
Actually, yeah. The GF3 is now hackable and is much lighter than the GH series.
cool thanks. I can't find anything confirming you can shoot normal progressive frame rates, 24p etc and manually control iris with the hack as these are the pitfalls of the camera.
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