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Old Feb 22, 2012, 01:15 PM
1.21 Gigawatts!
Steph280's Avatar
Irvine, CA, USA
Joined Oct 2000
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Askman: Yup those take M3 bolts.

Gary: Looking forward to it!

About those servos, do you know what amp draw is needed on average? MK uses these Recom R-785 power converter (BEC) that is rated only for 1 amp for all servos. Not sure if that's similar to the DJI power supply.
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Old Feb 22, 2012, 01:30 PM
Destroyer of G-10
askman's Avatar
United States, OR
Joined Jul 2004
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actually, the DSLR will have different LG/pan unit. I am working on it this week. The adapter for MK is really simple. I will be using the 4 outer holes that the gimbal attaches to. 2 small plate that replaces one that is used for 550L. I will get it cut and ship it to gary today.
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Old Feb 22, 2012, 01:53 PM
1.21 Gigawatts!
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Sweet! Thanks Andrey!
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Old Feb 22, 2012, 02:24 PM
Destroyer of G-10
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going to go drop it off at the PO
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Old Feb 25, 2012, 06:43 PM
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South Orange County, CA
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Sorry for the delay. I've got all the servos in now, but they still need to each be programmed. I still don't have the website up, but it is only because I had to transfer the domain registration from Network Solutions to GoDaddy, in order to get special package deal they were offering. Apparently, that takes about 5 days, so I still have a couple to go.

We've also made a few more tweaks. We had to make the camera tray/plate a bit wider, and add a second slot, in order to support using the NEX-5N/7 with the standard 18-55 "kit" lens. This allows the camera body to be farther back in the yoke, so that the whole assembly balances. Originally, we were only supporting the "pancake" lens, because we were concerned that the extra weight would be too much for the tilt servo. That concern went away once we decided to switch to the full-size DH20x-GCD, but we forgot to update the plate. Anyway, Andrey is cutting replacement plates for the gimbals I have in hand. Obviously, this doesn't affect the GoPro version.

Another change we've made is to add one more layer of isolation, this one between the F550 lower plate and the landing gear mounts. We are now using rubber grommets in the outer circular slots, on the bottom F550 plate (see attached...). This isolates the LG first, and then the 2nd layer of isolation is between the LG and the gimbal mounting plate/battery tray.

Here's my latest video:

F550 GoPro Gimbal Test-15.mp4 (2 min 56 sec)



As you can see, I've got the gains pretty well spot-on now, and the "extra" isolation has eliminated any hint of "jello". There were some pretty good wind gusts this morning, which caused some aggressive WK-M position hold corrections and I was not trying to fly smoothly at all. Nonetheless, the video came out pretty smooth, all things considered. You can see the arms coming into view a view times, and when I had it down low, I was really yanking it around, as you can see in the inset video.

I'm going to spend the rest of the weekend, packaging up this first lot, so that they are ready-to-ship on Monday. The NEX version will ship just as soon as I get the new camera tray plates from Andrey.

Until I get the website up and running, I will start doing this first lot as direct sales. If you are interested, please email me at ggoodrum@tppacks.com. What I have right now are the TP450-GP-2 front-mounted 2-axis GoPro gimbal ($375 + shipping), for the F450 quad, and the TP550-GP-2 2-axis GoPro gimbal that includes the landing gear setup ($475 + shipping), for the F550 hex. Once the new camera plates arrive, I can also start shipping the TP550-NX-2 NEX/GH2 gimbal, which also includes the LG setup ($500 + shipping). The F450 gimbal/front mount comes fully assembled, with the servos installed and programmed. The TP550 NEX and GoPro gimbals come fully assembled, but the landing gear comes in three assemblies, plus the two skids, so some minor assembly is required (bolt on the two legs, and attach the skids...).

Anyway, I'm real happy about how well the mount is working.

-- Gary
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Old Feb 25, 2012, 10:04 PM
I never finish anyth
United States, TX, Houston
Joined Jan 2012
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Solid work Gary, looking like its ready for some happy customers!

Don't forget the hard mounted gopro, I am really curious to see the two videos side by side.
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Old Feb 25, 2012, 11:55 PM
Destroyer of G-10
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United States, OR
Joined Jul 2004
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Remember even a well designed mount takes fairly amount of work to get maximum performance. especially tuning the gain and controlling vibration. we are finding that you really need to either isolate the fcb/gimbal controller or really take care in vibration if you want max performance. anyway, I am really happy with the lvl of stabilization we are getting. I won't rest on may laurels either. if I can find way to improve it, I will continue to work on it.
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Old Feb 26, 2012, 12:05 AM
manual flying apologist
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United States, CA, Fresno
Joined Mar 2011
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Words to live by.

I am currently battling vibrations getting to my FC. The mount handles vibrations better with the servos off. When I get vibrations to the FC it magnifies to the gimbal.

I have rubber isolators on the FC and the gimbal and I spend 2hrs rebalancing props.

Vibrations are the enemy. Hopefully I get a good solution figured out tonight to get some footage tomorrow.

Well built mount and fun to fly with.

here is a video showing my progress with the mount....
Askman's Gimbal Test Flight Y-6 Nex-5n HoverFly Y-6 (4 min 22 sec)
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Old Feb 26, 2012, 10:44 AM
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Quote:
Originally Posted by askman View Post
I just had a thought this morning. I know to some of you, the price is an issue and want to buy it in upgradeable manner.

What do you think about this. Th nex-5 yoke with the mounting system that is on this LG is very easy to make it vertical tilt only gimbal. it would only require 2 standoffs to make this work and gimbal that could be predrilled for current mounting system. upgrade roll block will be available, if desired. I also know some would not mind just having smooth tilt only set as well. and it could be stabilized for tilt only. This option would only be available for nex5 or bigger gimbal. (including the dslr gimbal as tilt only)

The F550 askman modular system .
let me know what you guys think.
Not a bad idea. It seems to me Gary has the tilt jitter waaay improved with the new servo, but the controller seems slow on roll compensation. Roll compensation correction seems pretty reliable in post, so I think the tilt only option might be a good way to go without a Picloc or similar, although maybe a higher DJI refresh rate can help. The tilt jitter/twitch was impossible to correct in post. Gary's latest video (the one right above your post quoted above) looks like he has really nulled the twitch very good (good job Gary- you have done a bunch of work that will help us all... thanks).

I am slowly working my way through this thread. I am late to this party since winter and my workload had me sidelined for a while. I am anxious to reload for the spring season when in a couple weeks I catch up with my over loaded work schedule.

Good to see you back Askman. I still have a couple of heli mounts and one pole mount of yours.

I just had a great warranty experience with DJI on a GPS unit ... I just wanted to mention it here just to get that said since it is natural to only talk about problems and not the good experiences. Thanks Sidney, Fiona and Robert! Sorry for the off thread mention.

Tim
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Old Feb 26, 2012, 01:43 PM
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South Orange County, CA
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Quote:
Originally Posted by TimIndy View Post
Not a bad idea. It seems to me Gary has the tilt jitter waaay improved with the new servo, but the controller seems slow on roll compensation. Roll compensation correction seems pretty reliable in post, so I think the tilt only option might be a good way to go without a Picloc or similar, although maybe a higher DJI refresh rate can help. The tilt jitter/twitch was impossible to correct in post. Gary's latest video (the one right above your post quoted above) looks like he has really nulled the twitch very good (good job Gary- you have done a bunch of work that will help us all... thanks).

I am slowly working my way through this thread. I am late to this party since winter and my workload had me sidelined for a while. I am anxious to reload for the spring season when in a couple weeks I catch up with my over loaded work schedule.

Good to see you back Askman. I still have a couple of heli mounts and one pole mount of yours.

I just had a great warranty experience with DJI on a GPS unit ... I just wanted to mention it here just to get that said since it is natural to only talk about problems and not the good experiences. Thanks Sidney, Fiona and Robert! Sorry for the off thread mention.

Tim
The mount, with the second layer of isolation (between the LG and the F550 lower plate...), does a great job of eliminating the "jelly roll" that typically comes from props and motors not being perfectly balanced. What no isolated mount can do, however, is eliminate the same sort of vibrations from getting to the FC. In the video above, you can hear the servos "buzzing". This is what is causing a little vibration, occasionally, mostly while it is hovering. This buzzing is caused by the FC's gimbal outputs trying to make "corrections" for the platform vibrations. I have the props perfectly balanced, but I haven't yet done anything about the motors. The only way around this is that I can see is to use a separate gimbal controller, like a PicLoc, or maybe one of the new HoverFly Gimbal boards, mounted on the isolated side of the gimbal/mount. I'm not sure about this, but maybe another option is to move the WK-M's IMU to the isolated side. This might work, or it could screw up the basic flight characteristics.

I'm convinced that the gimbal outputs do not have an inherent lag. What is causing what appears like a roll lag is actually not having the gains perfectly set. I used a bubble level on this last adjustment, and got it pretty close, but with the GoPro's fisheye effect, roll "errors" are more readily visible. I will adjust this one more time today, before my next test flight.

There is another issue with the WK-M and Naza gimbal outputs and that is the update rate. From my tests, it appears they are using an update rate of 100Hz. This is too slow by a factor of about 4 or 5. What I have found is that the faster the update rate, the smoother small movements will be. At slower rates, small movements will be slightly jerkier than they will at fast rates. I have an original XA FC/AHRS V1 combo that I have used as a separate gimbal controller, and one of the controls you have is to set the update rate, from 2-20ms. This equates to a rate adjustment from 500hz down to 50Hz. When I set the rate to 10ms/100Hz, the FC/AHRS' gimbal outputs behave exactly like the WK-M' or Naza's outputs. If I max out the rate to 2ms/500Hz, and I zero out the deadband timing in the servos, small movements are buttery smooth. I'm putting together a video that shows the differences, to send to DJI. I'm hoping I can get them to make a change to speed up the update rate, because it does make a noticeable difference.

I've had a hard time finding a NEX-5N locally here, but yesterday I did pick up a Sony DSC-HX9V that I'm going to give a "shot". () What intrigues me is that like the NEX-5N/7, it does 1080p/60fps. What I'm not sure about is that it has a two-level image stabilization function, that has two settings, "Normal" and "Active", but I don't see a way to turn the function off. I have no idea whether one or the other would be helpful, or whether it will just make things worse, but I will try both.

-- Gary
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Old Feb 26, 2012, 01:51 PM
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The inherent problem with using fc boards to do both jobs is the issues that you are dealing with. You really need a place to mount an additional board to control the camera gimbal, on the camera gimbal. The current design has no real spot for this. You can always Jerry rig something, but it would be nice to see a place that the fc was designed to go. Also, it's a pretty good idea to be able to mount all of your downlink gear on the mount as well, and have room for a second rx, so those of us with two man crews can make good use of it. It truly then becomes modular, as you can disconnect the entire rig and move it from one setup to another without re-wiring everything.
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Old Feb 26, 2012, 02:26 PM
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South Orange County, CA
Joined Mar 2003
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Quote:
Originally Posted by MauiNate View Post
The inherent problem with using fc boards to do both jobs is the issues that you are dealing with. You really need a place to mount an additional board to control the camera gimbal, on the camera gimbal. The current design has no real spot for this. You can always Jerry rig something, but it would be nice to see a place that the fc was designed to go. Also, it's a pretty good idea to be able to mount all of your downlink gear on the mount as well, and have room for a second rx, so those of us with two man crews can make good use of it. It truly then becomes modular, as you can disconnect the entire rig and move it from one setup to another without re-wiring everything.
Check out the attached. I have an XA v1 FC/AHRS combo mounted on the top/front portion of the mounting plate/battery tray. A PicLoc3 or a HoverFly Gimbal board could also be mounted here, and if they both weren't vaporware still, I'd give one a try. What also "fits" is an FY-30A, which I've also tried.

The FY-30A works fine, in terms of update rates and the smoothness of small ouptuts, but the problem is that the gains are too hard to get just right. they use small pots that only have a 1/4-turn of motion. That's bad enough but you can only use half of that range, because the center of this range is off, with 1/8T in one direction being the max gain for that direction, and then 1/8T in the other direction, from center, being the max gain for the opposite servo direction. Having only 1/8T makes it pretty much impossible to get the gains dialed in just right. At some point, I may tear one of these down, and look at replacing these pots with some 10-turn versions, which should make it easier.

Th XA FC/AHRS, with v1.31 firmware, works great. It not only frees up the WK-M's X3 input, it also lets me use another slider to control/fine-tune the roll angle. I'll have more info and examples using this setup later.

Another option, if DJI will make the update rate change, would be to use a Naza as a standalone gimbal controller. It's cheaper, by quite a bit, than either of the PicLoc3 or HF Gimbal options.

-- Gary
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Old Feb 26, 2012, 05:13 PM
manual flying apologist
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United States, CA, Fresno
Joined Mar 2011
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i have a FY-20a, FY-30a, multiwii board and my 2 HFboards.

I intend on tests my 2nd HFpro board as a gimbal only contoller mounted to the isolated mount.

I will do the same with the 30a and multiwii board.

my FY-20a has twitchiness on the roll servo for some reason and will not used

I just shot another test video out front of my house and I am trimming it now and will post it.

getting the vibrations away from the FC is the hardest part. What is strange is the vibrations do not affect the flight characteristics.... just the gimbal movements.
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Old Feb 26, 2012, 05:46 PM
Destroyer of G-10
askman's Avatar
United States, OR
Joined Jul 2004
10,083 Posts
looks like things are hopping we all agree that we really need an affordable cam controller board that can dish it out.

good progress adidas. nice improvement wow.

the main reason you don't see the movement in real vs gimbal is the difference in PID between Flight and gimbal. I am guessing that gimbal code is much cruder P and no filtering. also, there is natural damping effect of the mass of movement that you probably don't get in the gimbal. We really need more sophisticated firmware for gimbal including filtering if we want to maximize the result. Multiwii would make a possibly decent code base for the gimbal controller. we just need some firmware help.
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Last edited by askman; Feb 26, 2012 at 06:02 PM.
Old Feb 26, 2012, 07:14 PM
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South Orange County, CA
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Quote:
Originally Posted by MCrites View Post
Solid work Gary, looking like its ready for some happy customers!

Don't forget the hard mounted gopro, I am really curious to see the two videos side by side.
This isn't a flight test, but it does show how well the gimbal is working. I dialed in gains a bit better this time, and I switched to the Sony HX9V. I stuck the GP on top.

F550 HX-9V Gimbal Test-01.mp4 (0 min 47 sec)
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