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Old Oct 12, 2012, 04:31 PM
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Originally Posted by tomeparker View Post
Great thread, great work. I'm currently after a gimbal just like these, buying one is far too expensive. I only need to have it hold a GoPro so I might be able to cut some weight once the design is fully refined.

Until then, I'm trying to get this printed on an FDM free of charge. http://www.thingiverse.com/thing:20080
The main issue is the direct drive tilt. It is very difficult to get a smooth stabilization with a direct drive servo. That's why we are using en external pot and a high ratio belt drive.
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Old Oct 12, 2012, 04:33 PM
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Here is a video from the second flight. I increased the tilt gain a little (5) and it is now a bit over compensating. I will reduce it just a bit next. I also see a bit of roll shake. I hope the new servo from Servo City will fix it. I really like the rigidity.


20121012 2 axis metal gimbal 2nd flight (1 min 43 sec)
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Old Oct 12, 2012, 04:45 PM
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very nice seismic!1 cant wait until Rusty has the kit....
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Old Oct 13, 2012, 04:47 AM
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Are dxf's, .skp's or pdf's of this project going to be available?
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Old Oct 13, 2012, 06:39 AM
tomeparker
United Kingdom, England, Cambridge
Joined Jul 2011
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^^^ This would be great, I would like to try and make one.

What is the role of the pot in the build? What is it controlling? Do you need a CC3D controller for the gimbal to work?

Can the gimbal have the pilot for the roll in the center without much change? I'm only after using this for a GoPro. Would be nice if I could change it in the future for a larger camera though.

Lot of questions I know, but im really excited about your work!
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Old Oct 13, 2012, 10:11 AM
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Quote:
Originally Posted by SeismicCWave View Post
Here is a video from the second flight. I increased the tilt gain a little (5) and it is now a bit over compensating. I will reduce it just a bit next. I also see a bit of roll shake. I hope the new servo from Servo City will fix it. I really like the rigidity.


http://www.youtube.com/watch?v=UDRJmA_o-PY
Cool.. I guess you are flying a quad in X? Possible to show part of the boom or motor in the video so as to ref how much the quad is going wrt the horizon?
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Old Oct 13, 2012, 12:28 PM
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United States, CA, San Diego
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Quote:
Originally Posted by SeismicCWave View Post
Here is a video from the second flight. I increased the tilt gain a little (5) and it is now a bit over compensating. I will reduce it just a bit next. I also see a bit of roll shake. I hope the new servo from Servo City will fix it. I really like the rigidity.


http://www.youtube.com/watch?v=UDRJmA_o-PY
What servo are you getting?
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Old Oct 13, 2012, 01:02 PM
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Originally Posted by msev View Post
Are dxf's, .skp's or pdf's of this project going to be available?
As I mentioned there is no need for drawings. You can just make the parts yourself. Rusty is also busy testing out parts and most likely will offer some sort of kits. The extend and completeness of the kits may vary.

The idea behind this gimbal is that you can be innovative and just pull parts off the shelf and create a usable unit. It is also scalable so you can make it any size.
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Old Oct 13, 2012, 01:09 PM
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>>This would be great, I would like to try and make one.<<

Excellent, that's the idea.

>>What is the role of the pot in the build?<<

The external pot is to increase the travel of the tilt servo. I am using a 2.8 to 1 ratio belt drive so I get very little tilt travel if I use a standard servo. Even if I use a 180 degree servo I am only getting 60 degrees travel total. For tilt many people like to get 90 degrees or more so the solution is to use an external pot.

>>Do you need a CC3D controller for the gimbal to work?<<

No, you can use two channels from your receiver to control the roll and tilt. That will have no active stabilization. If you want active stabilization you will need to use a gimbal control. You can either use the gimbal control that comes with many flight controllers such as Open Pilot CC3D, Naza M, HoverFly Pro, various Multi Wii controllers or may be even the KK2 (I have not play with one yet).

You can of course always use a separate gimbal controller board such as the HoverFly Gimbal controller or another flight controller as a stand alone gimbal control.

>>Can the gimbal have the pilot for the roll in the center without much change?<<

Yes, you may put the pivot anywhere on the back arm within reason.

>> I'm only after using this for a GoPro. Would be nice if I could change it in the future for a larger camera though.<<

In that case make a smaller one and just make some longer tubes later on.

Rusty is making a 4" wide prototype right now. I may tighten up mine and make a smaller one also.

Now that they prove to be rigid and stronger the next goal is to make it as light as possible.

Lot of questions I know, but im really excited about your work![/QUOTE]
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Old Oct 13, 2012, 01:11 PM
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Quote:
Originally Posted by prodriverex View Post
Cool.. I guess you are flying a quad in X? Possible to show part of the boom or motor in the video so as to ref how much the quad is going wrt the horizon?
I tested the two gimbals on two different multi rotor. I tested the carbon tube one on a quad and the metal one on a Y6. Pretty hard to show the boom on a Y6. I may put a vertical bar in front of the camera as a reference. Right now I am in the process of switch gimbals around.
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Old Oct 13, 2012, 01:16 PM
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Originally Posted by jcmonty View Post
What servo are you getting?
HS7945. Eventually I will try a HS7950. I am flying the metal one with a MKS on the tilt and a HS5995 (discontinued) on the roll.

So far I found there are very little difference on the servo. If you don't mind a little less roll travel a 90 degrees servo work well. If you want more travel a 180 degree servo will work but be prepared for a little ratcheting movement.

The tilt is pretty smooth because of the external pot but you do need some servo speed and gimbal control tuning to get the gain just right. So far I am mostly over compensating and when I adjust the gain I wind up under compensating the tilt. Partly is because of the servo lag. The servo tends to under compensate initially and over shoot if the multi rotor holds the angle.
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Old Oct 13, 2012, 02:58 PM
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Do you prefer the MKS or high-end hitec's more? On paper the hitec's seems to be better in most areas except deadband which is apparently adjustable (not sure if it can go any lower than 0.002 micros). I know gary and andrey prefer the MKS through all of their testing, which is making me lean towards the MKS.

What's the travel on the standard MKS (no ext pot)? I am guessing 120 deg?
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Old Oct 13, 2012, 03:11 PM
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RE kit components for remote parts of the planet.

Quote:
Originally Posted by SeismicCWave View Post
As I mentioned there is no need for drawings. You can just make the parts yourself. Rusty is also busy testing out parts and most likely will offer some sort of kits. The extend and completeness of the kits may vary.

The idea behind this gimbal is that you can be innovative and just pull parts off the shelf and create a usable unit. It is also scalable so you can make it any size.
Just a comment about the proposed kits.

I hope that the kit will have an option for supply of pulleys, belts etc, unless these components are easy to source from another supplier who ships internationally with fair freight policies.

Many of us in the RC world do not have local suppliers of that sort of specialist hardware. It can be difficult and expensive to deal with multiple off- shore suppliers for a project.

So a plea, can there be an option for a Ready-to Build or Almost-Ready to build kit. IE stuff like bearings, pulleys, and belts, fixings etc IE everything less servos. I understand why a re-seller may not want the potential head ache of returned faulty servos.

Even AL tube can be a PITA to get when the supplier won’t cut it and you have to buy a 5 meter length of it. (16.4 Feet US )

Paying a suppliers margin on ready to build is good value for the convenience and certainty of the right parts and a rapid build. Shortening suppplied tube for a custom build is an option for scaling a kit.
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Old Oct 13, 2012, 04:19 PM
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Navarre, FL
Joined Mar 2002
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I'm glad to read comments about what the kits should contain, so thanks

The minimum I can see is a kit with only the G10 and Delrin that I cut. Maximum would be a fully built, ready to fly gimbal. Everything in between is somewhat negotiable, but I plan to stock everything in the kit with the possible exception of servos, depending on whether I can get them below retail.

Cheers,
Rusty
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Old Oct 13, 2012, 05:01 PM
tomeparker
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Thanks for the answers, I shall wait patiently now
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