OMP M2 (V2) with uB...
 
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OMP M2 (V2) with uBrain, tail issuses


JustPlaneChris
(@justplanechris)
Active Member Customer
Joined: 4 months ago
Posts: 10
Topic starter  

Hello! I'm hoping to get some assistance. As a long time Brain flyer, I can't seem to get the OMP flight control system tuned to "feel" right. Since I had a spare uBrain, I purchased another OMP ESC board (which has main and tail ESC) and wired it up so I could connect to the uBrain. All of that works fine, and I was able to get the heli into the air, but not without several tipovers and a couple of crashes. Here's what happens:

If I flick out of throttle hold the heli violently spins counter clockwise. If I hold almost full right rudder when I flick out of throttle hold I can sometimes keep it from spinning and tipping over. 

Once everything stabilizes I can lift off, but the tail motor is rapidly surging as if the gain was too high. I've reduce the gain to the point where the tail wanders around, but it still surges.

I have tried adjusting the PID settings, the gain, etc. I can't seem to get it to work, and I'd really like to! I have the Brain in all my other helis, but at this point I'm ready to give up and reinstall the stock flight control system.

I've attached the setup and log file. I don't know what kind of firmware OMP uses in their ESCs, so I'm sorry I can't provide that info. 

Chris

 


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BrainDev
(@customercare)
Member Admin
Joined: 3 years ago
Posts: 638
 

For a better diagnosis of the behaviour of the tail motor control, you should add other parameters related to the tail behaviour instead of the parameters you do not need for your specific problem.
From the tail rotation speed graph (TailRotationRate Deg./Sec parameter), you will be able to better understand if, with the ESC you are using, the output signal controlling the tail (TailOut%) should move earlier and faster or later and more gradually or should be kept more stable (or less stable).

Immagine

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JustPlaneChris
(@justplanechris)
Active Member Customer
Joined: 4 months ago
Posts: 10
Topic starter  

OK. I wasn't aware that I had to choose specific things to log. I thought by enabling logging it would log everything. My bad.

At this point I've already removed the uBrain, having broken the helicopter three times trying to get it to work. If it's going to be this difficult and frustrating to get it working, honestly it's just not worth it to me. Maybe at some point I will revisit it, but I'd rather not destroy the helicopter in the process.

Thanks for the reply. Maybe this discussion will help someone else who wants to give it a try.

Chris


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francesco.loco88
(@francesco-loco88)
Eminent Member Customer
Joined: 4 months ago
Posts: 21
 

braindev i can speak?

I have brain 2 bt and with all parameter standard my helicopter flies very well.

It seems to me that you have one problem of point neutral of the tail.

Is one regolation mecchanic and it is not one adjustment of the brain.

With straight bracket of the servo tail the blade tail must have the inclination right to hold the nose of helicopter stationary without to press the stick.

This test you do it in normal mode (no block tail).

Certainly you have put the blades tail in an incorrect position.

braindev if i don't have to talk in this forum (in the topic of the others people) i do not do it anymore


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JustPlaneChris
(@justplanechris)
Active Member Customer
Joined: 4 months ago
Posts: 10
Topic starter  

Hi Francesco! I appreciate the suggestion, but the M2 has a motor driven tail with fixed pitch blades. The issue is with how the uBrain handles the signals for the tail motor's speed controller. 

Chris


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francesco.loco88
(@francesco-loco88)
Eminent Member Customer
Joined: 4 months ago
Posts: 21
 

i have created one plane rotatory that can only rotate, so the model he can not crash.

The first tail setup  you do it on the plane rotatory with pitch blade at 0 and the plane and the model well fixed.

And now you go the first setting brain tail

20170401 145919

 


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maciej.j.wnuk
(@maciej-j-wnuk)
Active Member Customer
Joined: 9 months ago
Posts: 19
 
Posted by: @justplanechris

I can't seem to get it to work, and I'd really like to! I have the Brain in all my other helis,

Did you manage to make it work?
I'm considering buying M2, but only if I can use it with normal, configurable FBL (I have a spare Brain2).

How does M2+Brain combo behave during normal 3D flight? I tried flying my friends M2 with stock flight controller and I didn't like it - tail was too glitchy, too weak to hold well during harder punchouts or backwards hurricanes. Maybe he didn't tune it right, but theres not much to tune there afaik..


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JustPlaneChris
(@justplanechris)
Active Member Customer
Joined: 4 months ago
Posts: 10
Topic starter  
Posted by: @maciej-j-wnuk
Posted by: @justplanechris

I can't seem to get it to work, and I'd really like to! I have the Brain in all my other helis,

Did you manage to make it work?
I'm considering buying M2, but only if I can use it with normal, configurable FBL (I have a spare Brain2).

How does M2+Brain combo behave during normal 3D flight? I tried flying my friends M2 with stock flight controller and I didn't like it - tail was too glitchy, too weak to hold well during harder punchouts or backwards hurricanes. Maybe he didn't tune it right, but theres not much to tune there afaik..

I didn't get it to work, but to be honest I just didn't feel like messing with it any further because I was running out of spare parts to fix it after each attempt! I feel like the issue may be the mid point setting for the tail "servo" in the uBrain settings, but I wasn't able to find the magic number that would coordinate the startup speed of the tail motor with the ramp up of the main rotor. If I held full right rudder I could sometimes get it spooled up without it freaking out, but then once in the air the tail was wagging uncontrollably. The sad thing is, the cyclic felt wonderful (better than the stock unit) but without a functional tail system it doesn't really matter.

Your friend must have an early version of the M2, because the latest ones have amazing tail control and response. I honestly can't tell it from a regular heli tail, it's that good. The other thing you have to do is program around the dead band / massive expo they built into the cyclic, or it just feels weird. That was the main reason I wanted to try the uBrain, but I was able to use custom curves in my Taranis to make it feel right.

Chris


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maciej.j.wnuk
(@maciej-j-wnuk)
Active Member Customer
Joined: 9 months ago
Posts: 19
 

@justplanechris did you use Brain governor for the main rotor? Maybe this could be fixed with brains spoolup ramps


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JustPlaneChris
(@justplanechris)
Active Member Customer
Joined: 4 months ago
Posts: 10
Topic starter  
Posted by: @maciej-j-wnuk

@justplanechris did you use Brain governor for the main rotor? Maybe this could be fixed with brains spoolup ramps

I did not, and I don't see any way to do it. There is no RPM-out capability on the OMP ESC, at least not that I know of. 

Chris


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Jimmy
(@jimm-y)
Active Member Customer
Joined: 4 months ago
Posts: 4
 

If you purchased the M2 v2 before Aug 2020 there is a TALY firmware update or if you check esc, if it's v4 then it's latest version, v3 can be updated if you check with your supplier.


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JustPlaneChris
(@justplanechris)
Active Member Customer
Joined: 4 months ago
Posts: 10
Topic starter  
Posted by: @jimm-y

If you purchased the M2 v2 before Aug 2020 there is a TALY firmware update or if you check esc, if it's v4 then it's latest version, v3 can be updated if you check with your supplier.

Mine is much newer than that, so it almost certainly has TALY. However, that won't help (or hinder) the topic at hand which is to try and get the OMP ESCs to play nice with the uBrain. 🙂

 

Chris


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Jimmy
(@jimm-y)
Active Member Customer
Joined: 4 months ago
Posts: 4
 

Another option, on Discord Flybar UK forum Marty McFly done same setup with the M2 so could be worth contacting him. 


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