Thread Tools
Feb 23, 2017, 09:40 AM
Registered User
What about current measurement on motor winding? You dont need it for example to better method of motor control like FOC? You try something with FOC?
Sign up now
to remove ads between posts
Feb 23, 2017, 09:53 AM
OlliW
Thread OP
Quote:
Originally Posted by alvedro
What about current measurement on motor winding?
would be cool, see post #3, would be cool to give it a try in future
Quote:
Originally Posted by alvedro
You try something with FOC?
http://www.olliw.eu/2017/field-oriented-control/
Feb 23, 2017, 02:56 PM
Registered User
kiosk's Avatar
that looks a lot like the same layout as a Z1 Tiny2 OlliW

great job thou, cant wait to try it out.....
Feb 23, 2017, 03:59 PM
OlliW
Thread OP
Quote:
Originally Posted by kiosk
that looks a lot like the same layout as a Z1 Tiny2
well ... it is true that I analyzed in depth the pictures of the Z1 which folks like you thankfully provided, and using the TLE is one of the outcomes, but otherwise ... you know, there are only that many variations to one and the same topic ... this motor module layout I had from day one of the NT concept, more than 1-1/2 years ago (https://www.rcgroups.com/forums/show...90&postcount=6), one month before the Z1 thread started, and of course also others had similar layouts, see marcia, Basecam, etc. pp ... there are only that many variations to one and the same topic
Feb 24, 2017, 09:36 AM
KD2PBU - Fly No Evil
davidbitton's Avatar
These motors just popped up on RCGroups. The OP is offering OEM. Maybe we could get them to use an NT motor module in lieu of their board.
Last edited by davidbitton; Feb 24, 2017 at 09:37 AM. Reason: fixed link
Feb 24, 2017, 12:29 PM
OlliW
Thread OP
thx
I have seen that thread, as well as the predecessor thread https://www.rcgroups.com/forums/show...r-and-slipring
it's a bit strange though ... people named xfh, llm, etc. talking to themselves ... and no pricing, no web page, no pictures of the PM2804 ...
Feb 24, 2017, 01:39 PM
KD2PBU - Fly No Evil
davidbitton's Avatar
Who knows?
Feb 24, 2017, 02:03 PM
OlliW
Thread OP
iFlight has a broad selection of encoder gimbal motors: http://www.iflight-rc.com/gimbal-mot...-encoders.html, they can be found also on "local" shops
all with AS5048 of course LOL
Feb 24, 2017, 03:05 PM
KD2PBU - Fly No Evil
davidbitton's Avatar
Quote:
Originally Posted by OlliW
iFlight has a broad selection of encoder gimbal motors: http://www.iflight-rc.com/gimbal-mot...-encoders.html, they can be found also on "local" shops
all with AS5048 of course LOL
sure, but i was looking at the concept of having a motor w/ the module inside.
Feb 24, 2017, 03:46 PM
OlliW
Thread OP
yes, that would be cool
but iFlight could consider doing this too
Feb 24, 2017, 06:34 PM
Registered User

Another way


I know that the distributed driver architecture has major advantages - but keeping in mind that there are thousands of Storm32 1.3x boards in existence and that you can now get them for about 20 bucks all over the place I think you are much more likely to get people going and testing the encoder setup with the attached as a possible architecture.

Your concept has much less wiring, but this wouldn't have any more wiring than anybody using Storm32 1.3x board with NT INU right now and still has all the measurement signal processing on distributed processors.

Or is the 2.4 board a necessity because of power requirements for that many NT modules?
Last edited by McTage; Feb 24, 2017 at 06:46 PM.
Feb 25, 2017, 02:37 AM
OlliW
Thread OP
Quote:
Originally Posted by McTage
keeping in mind that there are thousands of Storm32 1.3x boards in existence and that you can now get them for about 20 bucks all over the place I think you are much more likely to get people going and testing the encoder setup with the attached as a possible architecture.
I totally agree that other architectures could lower the entrance barrier substantially, but I'll nevertheless stick to "my" scheme ... it would mean substantial additional work (and time), and ... you know ... at the end of the day I'm doing this for me, my fun, and in this sense don't care much about that point

The situation is similar to when the STorM32 was introduced, it took about 1/2 year for the first cheap hardware to become available, and many people said I should adapt the firmware to the, at this time, widely available EvGCC boards ... it just got forgotten how projects run and fail

Quote:
Originally Posted by McTage
Or is the 2.4 board a necessity because of power requirements for that many NT modules?
yes and no
the firmware runs also on the v1.x boards
but you need a 5 V power trail, the v1.x's 3.3 V power trail isn't sufficient, so when using a v1.x board one has to feed in a 5V BEC, which I however guess one would have to do anyhow in order to power all that NT modules
(the TLE5012B need 5V, maybe their single disadvantage)

EDIT: this is actually not correct, according to the datasheet it works also at 3.3V, not sure why I thought it must be at 5V ...

so, I change to: when using a v1.x board one probably has to feed in a BEC in order to power all NT modules
Last edited by OlliW; Feb 25, 2017 at 12:17 PM.
Feb 25, 2017, 01:42 PM
Registered User

2.4 board also obsolete with encoders?


Since you would need a driver board with integrated encoder for Yaw that would make the yaw drivers on the 2.4 board be extraneous correct?

2nd INU would be extraneous as well with encoders correct?

So optimized package we would probably be a much smaller main board that is essentially the master controller, I/O and power supply?
Last edited by McTage; Feb 25, 2017 at 07:40 PM.
Feb 25, 2017, 04:19 PM
OlliW
Thread OP
yes, yaw motor drivers are not needed
as regards the 2nd Imu, I'm not yet sure, currently it is not used, and it is also not absolutely required, however I will test at some point if it adds some benefits
in principle, the minimum requirement is a "communication" port (usb, uart) for connecting to the gui, and a high-speed, 2Mbps capable uart port for the NT bus, that's all
so, yes, the main board could be extremely slim
Feb 26, 2017, 08:22 PM
OlliW
Thread OP

I'm getting impressed


ok, I have to say, I start to get more and more impressed with these encoders

as explained in post #3, it's not really clear to me why encoders should be much better performance-wise, and that so far I had no experimental evidence ... but this changes, and I guess I have to overturn my opinions and start to become an encoder fan !!

I made the firmware such as to allow to run both versions without ANY hardware changes, by just changing one parameter from the gui
of course the PID values are different for the non-encoder and encoder versions, but I tuned them both to work in the full angle range, that is, they might not be the most "aggressive" for one particular orientation, but overall I would say they both are kind of "optimal", and in this sense comparable.
I then moved the gimbal up and down and left and right quickly, and plotted the pitch and roll angles. The deviations from zero give a good measure of how well the gimbal works.
To be "fair", I switched off the 2nd IMU for the non-encoder run. With 2nd Imu enabled the deviations would be significantly smaller, BUT, and this is really a most important BUT: The 2nd Imu support is good a reducing the deviations at lower frequencies, 10 Hz or so, but fails to do so at higher frequencies, that is, it is not helpful in rejecting vibrations. Thus, comparing the behavior with 2nd Imu disabled should give a better idea of how well the controller would do at higher frequencies.
The result one such run is attached, and it is - IMHO - quite impressive:

With the non-encoder version pitch exceeds +-0.5, while with encoder it stays well below +-0.1. That is:

For this gimbal the encoder controller is at least a factor 5 better in pitch!

For roll the difference is less dramatic. Wau, I have not expected that. I guess, many who have said for long that encoders are better feel confirmed now, and they do so rightfully. No gimbal without encoders anymore .

Next I will see if I can manage to record also some data which shines light on the behavior at higher frequencies, 20 - 40Hz or so. The challenge will then be to build a DIY encoder gimbal for a GoPro-sized cam, or even smaller.

cheers, Olli


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Cool T-STorM32: The best STorM32 ever !? OlliW Multirotor Drone Talk 2 Feb 21, 2017 05:02 PM