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3d - Printworx

Printing 3d Forum

Today I Have Mostly Been 3-axis Gimbal

Started by Hands0n, Thursday,April 21, 2016, 22:56:25

Previous topic - Next topic

Hands0n

Thanks to @rotorx I this week received one of these




http://www.ebay.co.uk/itm/152018483099?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Formally described as a 3-Axis Brushless Gimbal w/ 32bit Storm32 Controller for Gopro 3 4.  I am using mine with an SJ4000 [pukka] which typically costs around £45 for the non-WiFi versions.

The Gimbal varies in price on EBay, I got mine from a UK location for £54.88 which is astonishing value for a 3-axis device.

This gimbal is built around a Storm32 which is a rather fabulous Open Source BGC.  The actual Storm32 alone can be had for around £15 from the likes of Banggood, ridiculously cheap.   But don';t let the price of the gimbal or the Storm32 kid you that you';re getting what you pay for.  This kit punches stratospherically above its price point. 

The kit itself arrives fully assembled barring the top mounting plate that fits to the aircraft.   It comprised of the following
- 1 x Aluminum gimbal installed 3 motors
- 1 x 32bit Storm32 Gimbal controller with on-board IMU
- 1 x IMU Sensor on the camera foot
- 1 x Mounting plate
- 2 x Allen keys for gimbal frame
- Cable ties
- Wiring to hook up to a Receiver

It didn';t seem to go through the full power initialization routine I expected so the first thing I did was to go to the Storm32 Wiki to find out how to flash it with the latest firmware (0.96 as it happens).  I made a boo boo here, more on that in a moment.

You will need an FTDI or USB/Serial device to flash the firmware, it isn';t done through the Storm32';s USB port.  A simple enough job though, and the software GUI that is packaged with each version of the firmware is very easy to work.

And this is where I made the boo boo - I installed the wrong firmware.  Unbeknown to me there are two firmwares, V2 which I first installed is for the Storm32 with NT IMU.  Version 0.9 is the latest for the Storm32 with I2C IMU, it was the latter that I required.   

The firmware installed okay, but neither IMU was working, the Camera IMU wasn';t present, and the on-board simply didn';t register.  I thought that I';d received a dud.

After a bit of trial and error, and then a quick RTFM of the wiki I found my error.  Having downloaded v0.9 it was mere minutes to a functioning Storm32 gimbal. Woo hoo!  :cool:

Setting up the gimbal in the GUI is not difficult.  There are various tabs which you need to visit to run the routines or do the work.



Gimbal Configuration is a semi-automatic routine, you must do this before anything else as it will set up the orientation of the board to the gimbal frame and motors.  The orientation of mine and that of @rotorx were different by 180 degrees of rotation!! 




Having configured the gimbal you can then get on to PID tuning, and the wiki has an excellent write up on how to do this.  In fact the wiki is rather world class compared to so many others.  Do take the time to carefully read the relevant bits.



Take your time here, read the wiki, re-do anything you';re not happy with.  It felt really different to PID tuning a multi-rotor, and it is.  It isn';t difficult, and getting it right reaps rewards...

One of the big features of the Storm32 is the second IMU.  It is disabled by default, but I can recommend enabling it as it greatly enhances the performance of the gimbal in terms of stability and effectiveness. 

Details about use of the second IMU are here ---> http://www.olliw.eu/storm32bgc-wiki/Using_a_2nd_IMU#Benefits_of_a_2nd_IMU

Conclusions
This gimbal kit is very well built and based on a powerful 32-bit BGC called the Storm32.  Open source hardware and software has delivered a very high quality product that is very capable at an extremely affordable price.

The gimbal frame is very well manufactured and assembled, where the wiring is neatly routed and the camera IMU is embedded protectively into the camera mounting plate.

At three times the price this would be a superb product. 

--
Danny
"Its better than bad, its good"

Current FCs: Pixhawk, APM 2.6, Naza M V2, Naze32, Flip32+ CC3D, KK2.1.5
Aircraft: miniMax Hex, DJI 550 (clone) TBS Disco, 450 Firefly, 250 Pro, ZMR250, Hubsan X4, Bixler 2

Gav

Nice mate. Great unit for the price, by the looks of it.

Sent from my LG-H815 using Tapatalk


Fletch

I';ve had the Storm controller for a while from RTF Quads

I have it on this gimbal - http://www.multi-rotor.co.uk/index.php?topic=18037.0

I';ve not messed about with it much but the little i have done it appears to be superb.  I wouldn';t recommend that gimbal as the motors are right on the max end of what the Storm can handle!

rotorx

Fletch

I wouldn';t recommend that gimbal as the motors are right on the max end of what the Storm can handle!


Would you be able to expand a little with some specifics on the above  :beer2:

Fletch

Friday,April 22, 2016, 09:25:32 #4 Last Edit: Friday,April 22, 2016, 12:03:17 by Fletch
Quote from: rotorx on Friday,April 22, 2016, 08:37:32
Fletch

I wouldn';t recommend that gimbal as the motors are right on the max end of what the Storm can handle!


Would you be able to expand a little with some specifics on the above  :beer2:


Oh ... I get you

I';ll find the info and get back to you ... I don';t have info to hand and it';s been a while since I';ve been online ...

Something to do with motor resistance

Sent from my Nexus 6P using Tapatalk

Hands0n

So, doing some electronic digging around ... here';s my findings which are open to any re-calculation basis my schoolboy math which was never the best in the county ::)

The motors have a published specification Resistance of 10 ohm
Therefore, the potential maximum current draw with a fresh and fully charged LiPo is likely to be as follows ...

3S, 12.6v, I = 1.26 amps
4S, 16.8v, I = 1.68 amps

The published specification of the Storm32 says that the maximum current capacity is 1.5 amp per motor.

It is probably advisable to use a DC-DC voltage converter to limit the voltage to 12v particularly if running with a 4S mains supply.  A 5 amp DC-DC should just suffice ...


Citations:
Storm32 - http://www.olliw.eu/storm32bgc-wiki/STorM32_Boards#STorM32-BGC_v1.3
Motor 2804 160T - http://www.alibaba.com/product-detail/Brushless-Gimbal-Motor-AX-GM-2804_60092462975.html
Calculator - http://www.ohmslawcalculator.com/ohms-law-calculator




--
Danny
"Its better than bad, its good"

Current FCs: Pixhawk, APM 2.6, Naza M V2, Naze32, Flip32+ CC3D, KK2.1.5
Aircraft: miniMax Hex, DJI 550 (clone) TBS Disco, 450 Firefly, 250 Pro, ZMR250, Hubsan X4, Bixler 2

Fletch

Yes that';s the problem I ran into ...its right on the current limit!

I use a pololu to maintain 12v

Sent from my Nexus 6P using Tapatalk


teslahed

I have one of these which I am using with a Xiami Yi. It';s on my new u580 pro aircraft.

I am still trying to tune out the last of the wobbles to get totally smooth video;

One circlip short of a quadcopter.
 1 lobe short of an antenna.

Fletch

http://www.rcgroups.com/forums/showpost.php?p=29141709&postcount=1246

A bit of info there, but i was right on the limit, and had to increase the ?vmax? settings to get the motors to hold well

Don';t have time to trawl just now to find the full info

Hands0n

Chris, have you worked through the Storm32 wiki';s Tuning Recipe?  It is very good, has a couple of short videos, and worked a treat for me - although I';ve yet to test it in flight.

The PID tuning was counter-intuitive to what we';re used to. In very basic summary the order is; VBatt, D, I and then P - and with Pan turned off ...and all the PID at zero to start with ... then working each motor';s column before moving to the next.

Looking at your video I think maybe a problem with Vbat being too low on the Yaw motor.  But it could equally be that PID there also. 
--
Danny
"Its better than bad, its good"

Current FCs: Pixhawk, APM 2.6, Naza M V2, Naze32, Flip32+ CC3D, KK2.1.5
Aircraft: miniMax Hex, DJI 550 (clone) TBS Disco, 450 Firefly, 250 Pro, ZMR250, Hubsan X4, Bixler 2