Precision Visions
Multirotor Pilot...
Hey Gary I live in Garden Grove Ca can we meet I'd like to get a first hand look at that gimbal, my f450 kit arrives today and I have the same interst in flying a gopro2 thanks and keep up the great work...
New GoPro-specific 2-axis gimbal for the F450...
- Thread starter GGoodrum
- Start date
Kilby
Active Member
Have you guys seen that x468 is making a landing gear/gimbal set up for the Flamewheel now? It looks pretty nice from the photos.
http://www.x468.com/
http://www.x468.com/
GGoodrum
Member
With all due respect, that gimbal is not really in the same class. It might be fine for doing still shots, but as I found out yesterday, in low light conditions, you need good vibration isolation, even for stills. This mount appears to "hard mount" to the bottom F450 plate.
For video, I think this gimbal will be severely limited. It uses a small servo in the tilt axis, in a direct drive configuration, which means for small corrections, there will be a "stair-stepness" to the gimbal movements, even with hi-res 10/12-bit higher end digital servos, which a $99 gimbal is not going to have. In the roll axis, they are using an even smaller micro HS-55 analog servo, with a mechanical linkage, which introduces a measure of slop, or backlash. From the geometry, it appears that even in the roll axis, they are sticking to a 1:1 ratio between angular movement of the servo arm and the roll angle. Small movements will not be smooth enough, in my opinion. finally, it has been my experience that the Naza and WK-M do not play nice with analog servos.
When Andrey and I set out to do this, the purpose was to address all the issues that limit excellent video performance. I had a checklist of what I knew were areas that we needed to address. My goal was to have a GoPro-specific gimbal that would fit on an F450 quad, and that would be optimized for producing great video. Here was my checklist of features that I think we needed to achieve this:
- Each axis needs a belt drive, in order to provide extremely smooth movements, even for small corrections. With higher than 1:1 reductions, however, there is speed penalty. From my own tests, I've found that a 2:1 ratio will provide the smoothness required, assuming hi-res digital servos are used, while still providing enough speed, if these servos are also fairly fast (.10-.11s/60 deg., or faster...). Speed is important so that the gimbal corrections don't lag platform movements.
- High speed, high resolution digitals servos are a must, and they should be programmable. We chose the Hyperion DH16-SCD digital minis, for this GoPro-specific gimbal, for several reasons. First and foremost, they are the highest resolution digital mini-size on the market. Most "higher res" digital minis are 10-bit, like the Savox SH-1357, for instance. The other reason is that these are easily programmed, using a PC app. What we do is open up the throw range to a full 180 degrees. This allows the full +/- 45 degrees of motion, for both axis. I've also used the programming app to fine-tune the deadband space to the WK-M/Naza's gimbal outputs, which improves smoothness.
- There needs to be an effective vibration isolation scheme. Even the tiniest of vibrations will come through to the video, usually in the form of "jelly roll". In my tests so far, I've not used the isolators at all, as I wanted to see the worst case for platform-related vibrations, so the gimbal is hard-mounted to the F450 lower plate. Now that I've minimized the prop-related vibrations, I'm going to install the vibration isolation plate.
- Finally, I wanted to make sure that this gimbal was compatible with using the GoPro's waterproof case. With my old GoPro, I ended up scratching three lenses, with even the mildest of "mishaps" (rolling over, on the grass, was one...), so I won't use a GoPro now without the case.
Anyway, this gimbal/mount is very robust, it has a very effective vibration isolation/mounting scheme, and it meets/exceeds the criteria that I've established above for achieving excellent onboard video performance. Attached are a few shots of its current configuration.
-- Gary
For video, I think this gimbal will be severely limited. It uses a small servo in the tilt axis, in a direct drive configuration, which means for small corrections, there will be a "stair-stepness" to the gimbal movements, even with hi-res 10/12-bit higher end digital servos, which a $99 gimbal is not going to have. In the roll axis, they are using an even smaller micro HS-55 analog servo, with a mechanical linkage, which introduces a measure of slop, or backlash. From the geometry, it appears that even in the roll axis, they are sticking to a 1:1 ratio between angular movement of the servo arm and the roll angle. Small movements will not be smooth enough, in my opinion. finally, it has been my experience that the Naza and WK-M do not play nice with analog servos.
When Andrey and I set out to do this, the purpose was to address all the issues that limit excellent video performance. I had a checklist of what I knew were areas that we needed to address. My goal was to have a GoPro-specific gimbal that would fit on an F450 quad, and that would be optimized for producing great video. Here was my checklist of features that I think we needed to achieve this:
- Each axis needs a belt drive, in order to provide extremely smooth movements, even for small corrections. With higher than 1:1 reductions, however, there is speed penalty. From my own tests, I've found that a 2:1 ratio will provide the smoothness required, assuming hi-res digital servos are used, while still providing enough speed, if these servos are also fairly fast (.10-.11s/60 deg., or faster...). Speed is important so that the gimbal corrections don't lag platform movements.
- High speed, high resolution digitals servos are a must, and they should be programmable. We chose the Hyperion DH16-SCD digital minis, for this GoPro-specific gimbal, for several reasons. First and foremost, they are the highest resolution digital mini-size on the market. Most "higher res" digital minis are 10-bit, like the Savox SH-1357, for instance. The other reason is that these are easily programmed, using a PC app. What we do is open up the throw range to a full 180 degrees. This allows the full +/- 45 degrees of motion, for both axis. I've also used the programming app to fine-tune the deadband space to the WK-M/Naza's gimbal outputs, which improves smoothness.
- There needs to be an effective vibration isolation scheme. Even the tiniest of vibrations will come through to the video, usually in the form of "jelly roll". In my tests so far, I've not used the isolators at all, as I wanted to see the worst case for platform-related vibrations, so the gimbal is hard-mounted to the F450 lower plate. Now that I've minimized the prop-related vibrations, I'm going to install the vibration isolation plate.
- Finally, I wanted to make sure that this gimbal was compatible with using the GoPro's waterproof case. With my old GoPro, I ended up scratching three lenses, with even the mildest of "mishaps" (rolling over, on the grass, was one...), so I won't use a GoPro now without the case.
Anyway, this gimbal/mount is very robust, it has a very effective vibration isolation/mounting scheme, and it meets/exceeds the criteria that I've established above for achieving excellent onboard video performance. Attached are a few shots of its current configuration.
-- Gary
Attachments
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GGoodrum
Member
My wife plays tennis with several brokers, and I used to do quite a bit of airborne stills for some of their larger properties, using the heli-based systems I had about five years ago. I never made a lot of money dong that, as I had quite a few "incidents" and it seemed each one was like $500. Anyway, I got out of all that until now. With this setup, doing these sorts of RE shots are a piece of cake, so when one of her friends asked if I still did this, I let her say yes.
As a result of this one, I've got three more to do next week. -- Gary
GGoodrum
Member
Sorry, I didn't mean for it to come across that way.
The 468 gimbal/mount certainly has a place in this market, and frankly, I'm pretty amazed at what they've been able to offer for $99. Another reason we decided to do this mount/gimbal is that there really isn't anything on the market between the $99 X468 and the $790 AV-130. There also were not any quality gimbals I could find that we're tailored to the GoPro, with the case.-- Gary
Precision Visions
Multirotor Pilot...
Still would like to get a look at your setup gary im in retested in purchasing a belt drive mount do you have any for sale?
GGoodrum
Member
As soon as we are done testing, we will have some for sale. Andrey is getting setup right now. I just need to test the configuration with the F450 bottom plate mounted sideways, and test the new vibration isolation plate. These test should be finished early this coming week.
-- Gary
GGoodrum
Member
Well, my setup right now uses rubber grommets as well, but I consider this to be more or less "hard-mounted". Technically , it is not, but what we have is different. The platform is mounted to a plate, which is then mounted to the gimbal mounting plate. There is a compression isolation/dampening mounting system on the special plate that provides a very effective dampening of the medium to high frequency vibrations that are typical on a quad. To test its effectiveness I will purposely use props that are not balanced.
UAVproducts
Formerly DJIUSA
Looking good Gary.
Make sure to make it fit the F550 Hexa. I'm scrapping the little F450 for the Hexa. Really liking it over the Quad.
As soon as one is available I want one.
Make sure to make it fit the F550 Hexa. I'm scrapping the little F450 for the Hexa. Really liking it over the Quad.
As soon as one is available I want one.
GGoodrum
Member
Thanks, Robert.Looking good Gary.Make sure to make it fit the F550 Hexa. I'm scrapping the little F450 for the Hexa. Really liking it over the Quad.As soon as one is available I want one.
Actually, we also have a slightly larger version that is optimized for use with the new DJI F550 Hexa. I have a set of plates and legs here that Sidney sent me, and I will be building it up tomorrow. This version is slightly larger and is sized to carry a NEX-5N/7, a GH2 or a 550, and it will come with a special integrated set of landing gear. Attached are a few more pics of the more or less "final" configuration of the F450 quad GoPro2 mount. This now has the vibration isolation plate installed, and I've turned the F450 lower plate 90 degrees, which brings the camera/gimbal a couple inches closer to the center. There's also room now to mount the packs on top of the gimbal plate/battery tray. All-in-all, this is a much cleaner setup.The isolation/dampening setup works a treat. First thing tomorrow I'll shoot some video with this setup.
-- Gary
Attachments
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digitalcam
Member
Gary, I like the idea of the camera and the batteries set out wide like that. It's like the bar a tightrope walker holds, with the weights out on the ends. It makes it more stable. -- JOHN
GGoodrum
Member
I just did a quickie test flight, with the new gimbal position and with the vibration isolation plate installed. First thing I noticed is that I had the gains way too high. It had a crazy oscillation. I landed dialed the gains down and tried again. It still was oscillating, so I landed again. 3rd time was a charm. Anyway, it worked quite well, no vibrations I could detect. :02.47-tranquillity:
I was cranking it around quite a bit, on purpose, but for the most part, it was hard to tell. I can still see a very slight movement in the roll axis, so I will try tweaking the roll gimbal gain a bit more.
It could be that the roll movements are a slight lag, due to servo speed. On 5V, these servos run at .12s, which is borderline for use with a 2:1 belt drive. These can be run on 7.4V, however, which gets the speed down to about .10s.
I'm off to my mother's house this afternoon, so I'll try to get some more video of how well this is working.
-- Gary
Anyway, it worked quite well, no vibrations I could detect. :02.47-tranquillity: I was cranking it around quite a bit, on purpose, but for the most part, it was hard to tell. I can still see a very slight movement in the roll axis, so I will try tweaking the roll gimbal gain a bit more.
It could be that the roll movements are a slight lag, due to servo speed. On 5V, these servos run at .12s, which is borderline for use with a 2:1 belt drive. These can be run on 7.4V, however, which gets the speed down to about .10s.
I'm off to my mother's house this afternoon, so I'll try to get some more video of how well this is working.
-- Gary
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GGoodrum
Member
Here is another short flight test that I did yesterday. This was the 3rd flight of the day, and I ran out of juice towards the end, and had the flashing LED. I haven't yet tried tweaking the roll gains any more, but I tried to fly a bit smoother, and it was much better. There was a pretty stiff onshore breeze that I had to fly into, most of the time, so the flying isn't as smooth as it could be, given my skill level. :highly_amused: The good news is that there were zero vibrations getting through, so the new vibration isolation plate was definitely doing its job.
This was at my mother's house, near Dana Point. My daughter and her fiance were enjoying the sunset, while working away on their laptops. Sign of the times, I suppose.
Attached are a few stills I took with the GoPro2 in the mode where it takes a pic every 2 seconds.
Anyway, I am very happy with how this is working now. I think we are ready to start cranking these out.
-- Gary
I haven't yet tried tweaking the roll gains any more, but I tried to fly a bit smoother, and it was much better. There was a pretty stiff onshore breeze that I had to fly into, most of the time, so the flying isn't as smooth as it could be, given my skill level. :highly_amused: The good news is that there were zero vibrations getting through, so the new vibration isolation plate was definitely doing its job. This was at my mother's house, near Dana Point. My daughter and her fiance were enjoying the sunset, while working away on their laptops. Sign of the times, I suppose.
Attached are a few stills I took with the GoPro2 in the mode where it takes a pic every 2 seconds.
Anyway, I am very happy with how this is working now. I think we are ready to start cranking these out.
-- Gary
Attachments
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DucktileMedia
Drone Enthusiast
I now have a program setup for these carbon fiber leg extenders for the F450. They allow clearance for the gopro to be attached directly to the bottom plate. They do however show up in the wide angle setting though. I would charge $20/set of 4.
View attachment 2356
View attachment 2356
Attachments
GGoodrum
Member
Nice.
With our mount, the gimbal is out in front enough that these extensions wouldn't be in view.-- Gary
Precision Visions
Multirotor Pilot...
So I've tried to talk to you at least 3 times Gary, is this getting through. I am in Garden Grove I'd like to meet up and see your gimbal. Please at least answer and tell me to f off if not interested...