Tri-Ronin(™) & Matek F405-CTR target testing

[Kevin_Erik]

Problem…

When Arming the Tri-Baby on the bench, (no props) the Motors and Servo spin up. Except the Tail-Motor stutters badly and starts to get hot. Changing to the 1-Shot ESC setting doesn’t appear to help either. (ESC’s calibrated)

Any ideas what could be causing this?
Keep in mind that this flew fine yesterday so I’m optimistic that it’s not another hardware issue.

Edit: Further testing reveals that the tail-motor spins up just fine (no stutter) when using the “Output-Tab / Test Outputs” feature but misbehaves when armed. ESC’s verified as synced via BLHeli Suite-32. Wonder if Tri-Ronin(™) is reacting badly in some way? (Motor spins up causing the gyro to feel a very slight change in orientation, thus changes the motors output)

[jihlein]

I don’t believe it’s a hardware issue. Although I’ve never seen this behavior, I think there’s something in the Triflight routines that’s over compensating for the servo tilt. Why only on this installation to date, I’ve no idea.

To confirm it’s the Triflight routines, simply disable Triflight in the UAVObject browser, and see if it behaves when setup without the compensation routines.

I’ll have to get my board installed in a frame when I get back from vacation……

Edit:
Looked over your setup screens, they appear correct. The only one that looks remotely suspicious is your input screen, it’s very different from mine, but that could be simply from how your Taranis is setup compared to mine. At any rate, that wouldn’t cause the issue you are having.

I have some LUA scripts I threw together a while back that have battery voltage on them, but no current info. I can post those when I return.

Regarding the autotune/tailtune order, if the copter is stable enough, do the tailtune first. I’m not sure it really matters, but that’s what I do. WRT the Baby tri, there’s some evidence that you will get a better autotune if you take the default P gains and divide them by 2 before autotuning. Also, after the autotune is applied, 0 the yaw D gain and see how things work. Then add D back in a little at a time. I’ve had little luck with the yaw D derm, and typically leave it at 0.

[Kevin_Erik]

Disabling Triflight allows the motors to spin up without stutter. (Yay!)

Question: My Tail mech moves to the copters “Left” as throttle is applied when I beleive it should move to the copters “right”. Guessing the Servo PWM’s needs to be reversed? It’s hard to know whats right here without field testing it. I can see it now… Spin baby spin!

Triflight settings are attached.

Attachments:

1. 

   Triflight-Settings.png
   

[jihlein]

Yes, I missed that when looking at the output pane. Swap the servo’s min and max endpoints, and that will reverse the servo direction. Also make sure at the neutral point the servo is at 90 degrees, it does not have to be set to 1500.

Also the settings you attached indicated the on ground tailtune wasn’t run, or at least didn’t terminate successfully. The servo speed and ADC endpoints are still at their default value.

Just to review – enter tailtune mode, pull pitch stick back, servo should dwell at the end and center points, then sweep back and forth a few times. After the sweep stops, exit tailtune mode.

I can’t recall if the on ground tailtune will fault or not if the servo is moving backwards.

[Kevin_Erik]

Re-enabled Triflight and Completed the Tailtune. Did this with Servo PWM values non-reversed.
Looks like it maybe ready for the first real flight and auto-tune. (No more motor stutter!) That is assuming that it doesn’t spin in place upon lift off.

Question: Should the copter be Armed or Disarmed for the Tailtune? I know that sounds stupid but the rotational mass of the motor will definitely affect the outcome.

Attachments:

1. 

   Tail-Tune-Completed.png
   

[jihlein]

There’s 2 phases for the tail tune.

1)On Ground, vehicle disarmed, tailtune mode selected. This sets ADC endpoints and servo speed.

2)In air, vehicle armed, tailtune mode selected while in hover. This sets the motor thrust factor. Vehicle needs be in trim, hands off sticks as much as possible. Land when complete. Exit tailtume mode, then disarm, value will be saved. If there is too much stick activity or yaw noise, this will not complete. There are beeper codes to indicate progress, but I can’t find my spreadsheet detailing the tones and may have to re create it. I think it might be posted in these forums somewhere, but need to look. I seem to recall 5 long beeps indicates success, 5 short beeps indicate failure. There are shorter beep strings that indicate the vehicle is in trim and recording data. Also note that the in air tailtune has absolutely nothing to do with the PID gains, which I think is often misunderstood.

Your values from the on ground tune look very reasonable. If the in flight tail tune is successful, the motor thrust value will change from 13.8 to the new calculated value.

[Kevin_Erik]

Ahh so it’s basically Triflight.
So in-air Tailtune before the Autotune?

[jihlein]

“So in-air Tailtune before the Autotune?”

If stable enough, yes. If not, I don’t think the order is that critical. I should note that the betaflight version does tailtune in attitude mode, while this version does it in rate mode. I find that easier, particularly so if the accel is not perfectly calibrated and the bird wants to drift in attitude mode.

[Kevin_Erik]

Had the first flight!

Good News: Copter was very smooth lifting off and responded better than expected.

Bad News: Tailtune had three beeps at end of process and four or five beeps upon disarming. (Tailtune was still enabled after landing) End result, Thrust Factor = 13.8. “Exit tailtume mode, then disarm, value will be saved.” Forgot about that!

Guessing the problem was that I’m used to performing Tailtune with some form of auto leveling active. (You mentioned this in a prior post) Had quite a shock, when i switched from Horizon to Tailtune and saw it start drifting strongly with the wind. Was able to keep in nearby but i think my stick inputs were enough to cause it to fail. It could be wrong about but this could cause a lot of oh-shit moments, especially for new flyers.

Anyways, once dinner is done and I can venture out alone, I’ll give it another go but this time in a much larger field.

[Kevin_Erik]

“you will get a better autotune if you take the default P gains and divide them by 2 before autotuning”

So are we talking about the dRonin defaults of P 20?
I had considered using Andy RC’s Tri-Baby tune and Autotuning it from there.

[jihlein]

I was torn with the rate or attitude mode for the tailtune function. After playing with both, I found it easier to get consistent results in acro mode. Not to adverse to changing it, but if it’s changed, it would probably be wise to do a 6 point accel calibration as part of the bench setup. We can explore that in the future if necessary.

Please post some pictures of your Matek405Ctr install in the Baby Tri. I didn’t like the power connector coming out the side, looks like battery wires could possibly interfere with prop. Power connector out the back solves that, but USB access is now tight, although a 90 degree USB cable may solve that.

[Kevin_Erik]

Notice in the pictures below…

There are four added caps, one thats part of the XT60 connector, one thats part of the 6V BEC, one micro LC Filter on the Runcam Split HD camera and a small one thats part of the Matek VTX for filtering. Still was able to keep the flight weight under 500 grams!

[jihlein]

“I had considered using Andy RC’s Tri-Baby tune and Autotuning it from there.”

Not sure how gains from a betaflight install will translate to the dRonin install. While PIDs should be PIDs, they can scale things differently in side the code.

Besides, the autotune module works best from an undertuned state, so as long as it’s flyable, low gains are a good thing for autotune. In fact, running autotune on top of a previous autotune will typically result in a worse flying aircraft, it doesn’t get iteratively better.

[Kevin_Erik]

Did another Tailtune run.

MotorThrustFactor 13.8 (*!$%)

Flew up in Horizon mode, got stable and swapped to Tailtune mode.
Only performed a few minor corrections as needed.
System gave three long beeps so I landed. Disabled Tailtune, then disarmed.
Whole flight was less than 2 minutes, Tailtune was maybe 30 seconds.

Maybe, I need to stay in Acro mode and level out manually before swapping over to Tailtune?

[Kevin_Erik]

@jihlein

Latest tune attempt.

Took off in Horizon mode, switched to Acro and got stabilized before activating Tailtune mode.
Hands were off the sticks except for small throttle bumps. Heard 3 long beeps that repeated over and over. (not heard in video for some strange reason) Switched back to Horizon to land as the low PID rates don’t give me a lot of control authority currently.

Not sure what I could be doing wrong here, any ideas?

Kevin

Attachments:

1. 

   Triflight-Tail-Tune-Failure.jpg
   

[Author]

Posts