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Oct 14, 2016, 06:25 AM
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BeeBrain (re)Tuning for Inductrix-like Handling




Note: qreacher has taken this ball and run with it (and then some!) with Project Mockingbird:

https://www.rcgroups.com/forums/show...like-Inductrix

Please check out his thread and the Project Mockingbird documentation. It'll get you even closer to inductrix-like handling than the outdated tweaks in this thread will!



Some people who have dropped a BeeBrain Flight Controller into their Inductrix frame have been disappointed with the results due to how different it feels from the original Inductrix flight controller. This got me curious to see if I could re-tune the BeeBrain to behave more like the original flight controller (mostly by fiddling with the rates and expo). Below are the settings that I've come up with.

My goal with these settings is not so much to match the flight behavior of the original controller exactly; I just want to get it within the same ballpark. To get it to be an exact match would require waaaaaay too much switching back 'n forth between flight controllers; I'd rather spend that time smashing my Inductrix into the walls zooming my Inductrix around the living room! People who are new to flying more advanced quads (or those who just prefer the feel of the original Inductrix) might find these settings useful as a starting point.

Unfortunately, I haven't found any way to do this entirely within Betaflight since the Inductrix flight controller has a bit of throttle mixed in with both pitch and roll, something that I don't think can be done in Betaflight. Most decent radios (and even some budget radios) have Mixer settings, however, so the throttle mix can easily be handled on the radio side.


A Word About PIDs
You may find that the PIDs in the screenshots below vary from your own. In most cases the PIDs in my screenshots are from earlier pre-release firmware builds and are a little different from the final Betaflight defaults. The final default PIDs will work very well for most people, so I recommend that you NOT change yours to match the screenshots unless you have reason to believe that they are a problem.

 Basic Betaflight Settings (All Versions)
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For auto-leveling, Angle Mode should be used instead of Horizon Mode. For those of you not familiar with Cleanflight/Betaflight, Angle Mode is one of the two auto-leveling modes; it limits the max tilt angle to a predetermined number; no matter how far you push the stick, the quad will never tilt beyond that angle. It's pretty much the same thing as the SAFE Mode on the original Inductrix flight controller. If you need help setting up the Flight Modes in BetaFlight, just post a reply here.

To more closely match SAFE Mode, the maximum angle that the Inductrix can tilt in Angle Mode needs to be reduced from the BeeBrain default. This is done by inputting the following commands in the CLI:

Code:
set max_angle_inclination = 450
save
This sets the maximum angle to 45 degrees and then saves the settings and reboots the controller. This will ultimately limit your speed, but it's a good starting point. Once you become comfortable with this, you can always come back and increase this number, or even switch to Horizon mode. Horizon mode is the second auto-leveling mode. Unlike Angle Mode, Horizon mode does not impose a maximum angle limit, allowing you do do flips and rolls with auto-leveling still enabled.

 Betaflight 2.9.x Settings
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I've upgraded to Betaflight 3.0.x, so I can't work with these settings anymore, but I'll keep these here for reference. I highly recommend updating your BeeDuctrix to 3.0.x!


The most important thing here is to disable Super Expo (just click the toggle). With that enabled, the Inductrix will feel sluggish around center-stick and absolutely crazy at the stick extents. This is not as big of an issue with Angle Mode enable, because the angle limit will kick in before too much of that Super Expo does, but when you switch to Horizon or Rate mode, that angle limit is removed and you're going to be in a world of hurt; I strongly recommend disabling it initially.

Setting the Angle strength to 80 like I've shown in the screenshot is important to making the Inductrix feel responsive in Angle mode (which you'll want to have enabled, as previously mentioned).

 Betaflight 3.0.x Settings
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As with 2.9.x, you're going to want to disable Super Expo. This is handled differently in 3.0.x and it can be a bit confusing at first. It's referred to as "Super Rate" in the 3.0.x PID Tuning page and Instead of the simple On/Off toggle that we had in 2.9.x, it's now a variable number that can be applied independently to Roll, Pitch, and Yaw. To disable it, all you need to do is set each of those values to ZERO.
 
 
The Mix
The Inductrix flight controller has a decent amount of throttle mixed in with Pitch and Roll. This is what keeps the Inductrix from dropping too much from extreme pitch/roll angles... and why, if you quickly juke back 'n forth on the elevator/aileron stick, you'll actually gain altitude. Unfortunately, I couldn't find a way to do this in Betaflight, so I ended up doing in in the transmitter Mixer settings.

I've found that mixing ~25-30% throttle into ELE and AIL feels about right on both the Taranis, DX7 and the Devo 7E. The Inductrix is so light-weight that it doesn't really seem to need any throttle mixed into Yaw, tho this is something that you may want to experiment with.

Below are some settings for Spektrum, OpenTX, and Deviation-based radios.
Spektrum Radios
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Copy the Mixer settings shown in the photos above and you should be good to go. That's my own DX7, so if anyone needs additional help, just let me know.
OpenTX-based Radios
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I don't actually own a Taranis radio, but I did play around with the simulator and came up with these settings with a little bit of guidance from Benedikt. The first shot is the main Mixers page followed by detailed Mixer Pages for Ele and Ail and the last shot is the custom curve that you'll need for both of the detailed Mixer pages.
Deviation-based Radios
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I used screenshots from the Devo 12 Emulator since it can fit an entire Mixer Page on a single screen. The other Devo radios have identical mixer settings; you'll just have to do a lot more scrolling to navigate through them.

Note that, when you increase the mixers to 4, it actually creates 4 unique mixer pages. The "Page < 1 >" value indicates which page you're currently on and all of the settings that you see below that apply to that page only. If you follow the screenshots above, you'll end up creating 4 mixers. The first Mixer Page is where you can configure a throttle curve. The second and third pages are the Ail and Ele mixes required for Inductrix-like flight behavior. The forth page is a Rudder mix where you can mix a bit of throttle into your rudder if you want to experiment with that.

I'll make a short video walk-thru of setting this up on the Devo 7E soon...
Note: The mix % necessary to maintain level flight is going to vary depending upon the weight of your Inductrix, the power of your motors, and whether you're using 2 or 4-bladed props. The best thing to do is to experiment a bit with the percentage and even the curve. Start from a perfect hover in Angle mode and then give it full ELE or AIL stick input. If your quad gains or loses altitude, adjust the percentage # accordingly. Next, try some smaller stick movements. If your altitude stays the same with the smaller stick movements, you're good to go, but if your altitude changes, you'll probably want to use a multi-point curve and spend some time tweaking it.
Last edited by ScottAllyn; Jul 05, 2018 at 12:44 PM.
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Oct 14, 2016, 04:27 PM
Registered User
This is great Scott! Make sure to join this group and share in here if you have not:
https://www.facebook.com/groups/BeeBrain/
Oct 14, 2016, 09:23 PM
Total Noob
question from a near noob here. why would you put this FC into the frame instead of just using the original FC?

what am i missing here please?
Oct 14, 2016, 09:23 PM
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Thanks, I'll definitely post something to the group.

I just updated the original post, shuffling some info around and adding my settings for BetaFlight 3.0.1. I'm treating that post as a Live document, so there will definitely be more changes to come. I'll post a reply if I do any significant updates.
Oct 14, 2016, 09:42 PM
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Quote:
Originally Posted by bigpix
question from a near noob here. why would you put this FC into the frame instead of just using the original FC?

what am i missing here please?
The original flight controller is tuned pretty well for the stock motors and SAFE mode, but when you add faster motors, it'll start to oscillate, especially in ACRO mode. If you're doing FPV with it, that'll result in some jittery video. The BeeBrain doesn't suffer from this at all.

Out of the box, the BeeBrain is more responsive and "tighter" feeling than the original Inductrix controller and can be tuned to match your flying style.

Yaw with fast motors on the original controller feels sloppy. If I do 2 or 3 full speed spins and then stop, the quad continues to spin for a little bit before slowly coming to a stop; it feels sloppy. In comparison, the BeeBrain comes to a stop almost instantly, even when the Yaw rate is twice what can be achieved on the original controller.

The Roll, Pitch, and Yaw rates on the BeeBrain can be increased well beyond the rates that you can get with the original controller and with Super Expo, you can tune the sticks so that that extra speed really doesn't kick in until you get to the ends of travel. This allows you to do rapid flips and rolls that you'd never be able to pull off with the original controller while still having the same level of control as the original controller over the majority of the stick range. I've done three flips in a row in my living room with the BeeBrain, tho admittedly it was by accident.

Those are my reasons, at least.
Oct 14, 2016, 10:12 PM
Total Noob
Thanks for this detailed and thorough reply.
So much ahead to learn and do.

Thanks again.
Oct 15, 2016, 12:48 PM
Registered User
Quote:
Originally Posted by ScottAllyn
Thanks, I'll definitely post something to the group.

I just updated the original post, shuffling some info around and adding my settings for BetaFlight 3.0.1. I'm treating that post as a Live document, so there will definitely be more changes to come. I'll post a reply if I do any significant updates.
Awesome. We have been working with Boris to get 3.0.1 pretty damn locked in. How are you liking it? All the PIDs, rates and settings are now default. All you have to do now is add your modes and you are good to go!
Oct 15, 2016, 09:57 PM
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Quote:
Originally Posted by newbeedrone
Awesome. We have been working with Boris to get 3.0.1 pretty damn locked in. How are you liking it? All the PIDs, rates and settings are now default. All you have to do now is add your modes and you are good to go!
I like it a lot. It feels a bit more dialed-in than the 2.9.x firmware and not quite as bat-poop crazy at the stick extents.

You should take advantage of the rate profiles to throw a few different configs into the firmware...
Oct 16, 2016, 06:05 AM
Quads and FPV it's not a crime
zimmy1958's Avatar
thanks for sharing
Oct 16, 2016, 03:25 PM
Registered User
Quote:
Originally Posted by newbeedrone
Awesome. We have been working with Boris to get 3.0.1 pretty damn locked in. How are you liking it? All the PIDs, rates and settings are now default. All you have to do now is add your modes and you are good to go!
Do you mean that the beebrains come preflashed beta 3.0 and tuned?
Oct 20, 2016, 06:59 AM
Registered User
That's something I want to know to! With winter coming the quads hardly get out and looking at converting my inductrixes into tiny whoopies.
Oct 20, 2016, 07:04 AM
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Quote:
Originally Posted by BE Thomas
That's something I want to know to! With winter coming the quads hardly get out and looking at converting my inductrixes into tiny whoopies.
Even if they're not currently shipping out with 3.0.1, it's very easy to flash the firmware. Once you flash 3.0.1, you'll have the latest PIDs & Rates.
Oct 21, 2016, 01:07 AM
Registered User
The flashing part I'm familiar with. Just tuning is'nt my thing (yet). So it would be interesting to know if its already tuned with 3.0.1. I know basic pids in Betaflight are already great but tis ain't no average mini-quad.
Oct 21, 2016, 04:22 AM
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Quote:
Originally Posted by BE Thomas
The flashing part I'm familiar with. Just tuning is'nt my thing (yet). So it would be interesting to know if its already tuned with 3.0.1. I know basic pids in Betaflight are already great but tis ain't no average mini-quad.
The BeeBrain is custom tuned in 3.0.1; it's definitely not using the default Betaflight PIDs.
Oct 23, 2016, 02:32 PM
Registered User
Can't thank you enough ScottAllyn, I was staggering around in Betaflight trying to 'dumb down' the BB to fly more like my stock Inductrix FPV. I was on the right track but seeing your numbers saved me about 20 tune attempts.
My machine has a rakon frame and the TW Sauce motors, I had way too much angle and way too much altitude bounce. I've tweaked your numbers just a little to give me more yaw authority and smoother pitch/roll transition.
Very happy, thanks !


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