Been testing a brushless gimbal on my quad, it's an own-design laser-cut Liteply gimbal which uses a Foxtech AIO (Martinez) controller ($50) and Foxtech 2208-70kv motors ($21). Information is a little hard to find on the controller and tuning of these things a little tricky but so far the results have been very encouraging.

The gimbal was laser cut from 2.5mm Liteply but needed some reinforcement to prevent flex so this is now version 3.1 :)

3mm or 4mm might be a little better in the stiffness dept. but this is not bad at all. It's also really light at less than 35g for the ply parts!

Camera is one of the new 1080p Mobius Camera's which is pretty amazing for the price of $70. just the colours are a bit saturated but that will be sorted out with later firmwares.

A very short video flying above my Johannesburg suburb showing the fantastic stabilization (Note: this is only 720p and I tried to keep the upload size small with a low bitrate, Youtube also takes some of the quality away):

 

Views: 4365


Moderator
Comment by Morli on August 14, 2013 at 12:08pm

How cheap ?   you mean without gimbal controller and BL motor

Looks good.  i guess you  cannot put any thing heavier.  cheers


Moderator
Comment by Graham Dyer on August 14, 2013 at 12:15pm

$50 for controller, $42 for motors, $5 for laser cutting, $10 for Liteply, $5 for Cyano, $70 for camera.

So $182 for everything, as I said, cheap-ish :) Not $3000 Zenmuse expensive.

Strength-wise this would be able to carry a GoPro and if one used 4mm ply you could put a small digicam on it, although it would have to be scaled for anything larger as it won't balance.


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Comment by Morli on August 14, 2013 at 12:22pm

K, great,   good work.

Comment by Serpentaire on August 14, 2013 at 12:25pm

Very stable video.  How do you fly the bird and control the gimbal at the same time?  Are the plans freely available for the pieces?  I guess, what I'm trying to ask is, do you have more details on how you construct/use this?  I've been looking for a good GoPro gimbal that could also hold a Canon P&S and this might work. 


Moderator
Comment by Graham Dyer on August 14, 2013 at 12:31pm

@Megaflare, I'm not flying FPV just line of sight in that video, currently there are no transmitter controls connected to the gimbal but you can add roll and tilt. The plans aren't available but I might publish them at a later stage. For a GoPro a fair bit of fettling would be needed to the plans because as with all brushless gimbals the camera must balance exactly, this was designed specifically for a camera the size of the Mobius

Comment by Wesley Versfeld on August 14, 2013 at 12:34pm
Looks very nice! Is that the PPC factory on the horizon?
I also use Martinez, but as you say it's tricky to tune and it seems sensitive to temp changes, working in my garage and when I take it out into the cold it vibrates. I also find that it clicks over and stops responding sometimes but I cannot figure out whats causing it? Could be the PWM or I terms too high, but with lower settings the gimbal doesn't stabilize - carefull fine tuning has sorted this out on mine but I'm wondering if you've experienced the same?

Moderator
Comment by Graham Dyer on August 14, 2013 at 12:47pm

Wesley, Sandton CBD actually. Yes I've had the same issues, it's a fine balance to get the PID's and PWM sorted, higher PWM holds firmer but you can get vibrations (I'm using around 40), my P's are quite low (5-6) and I's quite high (40-60), D's = 20-40.

Soft silicone IMU wires help a great deal and are almost mandatory IMHO. If the gimbal gets pushed over too far it sometimes goes crazy taking a while to settle. Also can take long to level then, much longer than normal stabilization but it sorts itself out. Must run on 12V (3S) at least I think, to get enough power for the motors.

Comment by Wesley Versfeld on August 14, 2013 at 1:07pm
Mmmm, I suspect mine could be faulty. There is a kick in the gimbal when it powers on, I guess while it's booting and then 2 - 3 seconds the gimbal stabilizes (normal I guess). After a while flying (only sometimes) it kicks again and then all hold is gone and it doesn't recover, even after landing and leaving it on for a while.

I'll give your PID ratios a try - thanks for providing them.
Comment by Mark on August 14, 2013 at 1:26pm

Graham, interesting comment on the wires, I hadn't even considered their affect on the gimbal, but it makes total sense.  I wonder if using a slip ring at the opposite side, like this one:

http://www.adafruit.com/products/775

would be viable... I can't find any MTBF stats or load stats on it, but could make for an interesting design to place opposite the motor.

Comment by Daniel Allen on August 14, 2013 at 1:50pm

Graham, very nice for the price! You may as well have gone for the RCtimer $18 motors, and 3-axis controller =D. You basically did what I was striving to do.

BTW are you using dampening? I've been at this hobby for 8 months and only recently have I started using wire dampening which helped. It took 8 months to realize prop balancing was not helping, it was Z-axis vibes from the prop pitch causing it.

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