Debugging the tricopter mini racer

[swissfreek]

Hm, no joy, I just get an error that it can’t connect. Will try to see if RadioShack still sells the Arduino starter kit (they used to), which comes with an Uno, I believe, and will give it another shot. If not, oh well. Lesson learned.

[lauka]

Had some fun at the local field with the RCExplorer Baby tricopter.

Skills are a bit rusty again, need to get to the track :).

[swissfreek]

The newborn Baby Tricopter, eh? Based on the teaser, I might start calling it “The Sea Creature”. Also, your version of “rusty” is better than anything I can do…

In other news, I did manage to get my OpenLog firmware flashed now that I went and got a new Arduino Uno, so as soon as I figure out something to prop up the tail servo, I’ll get you some logs of what I’ve been experiencing with my mini Tricopter. Hopefully later today.

[bhuism]

I bought an openlog from Banggood and could not program it as well via de FTDI, however I could program it with:

http://www.hobbyking.com/hobbyking/store/__42120__Atmel_Atmega_Socket_Firmware_Flashing_Tool_EU_Warehouse_.html

Choose Programmer:USBasp and Sketch -> Upload using programmer.

I bought another Openlog (safety first ;):

https://www.unmannedtechshop.co.uk/openlog-black-box-flight-data-recorder/

which flashed fine via FTDI.

@lkaino many thanks for triflight_0_5_candidate2_F3FC.zip, it flies great and I now can use blackbox logger on UART3.

[swissfreek]

Yeah, it took me a while to get sorted out as well. Turned out I needed to update the bootloader as someone mentioned earlier today. Wouldn’t take with my old Duemilanove, so I went to RadioShack and spent *way* too much money on a Uno starter kit, and that worked on the first try. I quickly went and updated all four loggers that I got, so now I’ve got a logger for every quad and a spare (which looks like it won’t be a spare for long ;)).

[jihlein]

@lkaino: I’ve been studying the triflight code, and think I found a units error. In initCurves:

    tailMotorPitchZeroAngle = 10.0f * 2.0f * (atanf(((sqrtf(tailServoThrustFactor * tailServoThrustFactor + 1) + 1) / tailServoThrustFactor)));

    tailMotorAccelerationDelay_angle = 10.0f * (tailMotorAccelerationDelay_ms / 1000.0f) * tailServoSpeed;
    tailMotorDecelerationDelay_angle = 10.0f * (tailMotorDecelerationDelay_ms / 1000.0f) * tailServoSpeed;

tailMotorPitchZeroAngle is in radians, the 2 delay angles are degrees (ignoring the deci scaling).

Later in the getPitchCorrectionMaxPhaseShiftFunction, these values are summed together in a few places. One example:

if (((servoAngle > servoSetpointAngle) && (servoAngle >= (motorDirectionChangeAngle + motorAccelerationDelayAngle))) ||

Motor DirectionChangeAngle is in radians, motorAccelerationDelayAngle is in degrees.

Am I missing something, do I possibly have an older version of the file, or does tailMotorPitchZeroAngle need to be converted to degrees?

[lauka]

@jihlein: good catch. I remember testing that functionality but it seems that there is a bug. Haven’t noticed anything odd in the blackbo logs though.

[swissfreek]

@jihlein, I have a BrainRE1 coming to me when the pre-orders ship, and I figure that the baby tricopter would be a frame worthy of such a flight controller. How can I go about installing/testing your triflight additions to the dRonin code? I’m not a github expert, nor have I ever built my own hex from source before, but if there’s a way I can do it through there, I’d be happy to with some instruction.

[jihlein]

@swissfreek, I’ll build an installer package with latest later today and post a link to it. If you install that package you won’t have to worry about github or building the code files.

There’s a patch to the BrainRE1 target I want to get into the build.

I need to work on some setup instructions. Are you familiar with Dronin and how to setup Dronin?

[swissfreek]

I haven’t actually set up dronin yet, but my first tricopter had a CC3D on it with OpenPilot, and I also have an original Brain that has TauLabs on it, so I’m familiar with the GCS and setup process in a general sense. Just haven’t messed with it much in the past year or so.

[swissfreek]

Also, I’m currently tracking that the BrainRE1s won’t start shipping until the beginning of August, so there is no rush for you to make the package today. Especially if you think there might be changes in the next couple weeks anyway.

[jihlein]

@swissfreek, you can find the installer at: https://1drv.ms/f/s!Am7KDquQANJl4ADT24ADMeN9cUgg

This has all the Dronin supported targets, plus a couple extra that I added off tree, including the F3FC. I’m thinking a specific thread for this is appropriate, not sure if here or the Dronin forum though….

I have a BrainRE1, so I needed to build this anyway. I’ll update the installer as I add more of the Triflight specfic functions. I’m working on dynamic yaw now.

I really need to fly this some more, I’m not 100% sure if some odd behavior I had on one of my last flights was due to a bad tune or the tail motor tilt compensation into pitch not working correctly.

[swissfreek]

Oh, you’re one of the lucky ones, cool! Well good to know that it is in the hands of someone who will ensure that numbskulls like me have a pleasant experience when we get ours.

Since there’s an F3FC target and my big Tricopter is flying well, I’m tempted to flash it on there and see what happens. The latest Triflight release finally made my mini reliably flyable for the first time since last fall, so I’m a bit loathe to mess with it at the moment. It’s so good I might even race with it this weekend.

Anyway, thanks for the installer package. I’ll give it a try as soon as I get a chance in the next few days.

[lauka]

Have been flying the baby through 30 packs this week. Really like how the 0.5 flies. Only thing bothering me is the throttle cut issue. Maybe we can do something about it…

I have got rid of the yaw wiggling on throttle punches by decreasing the tri_dynamic_yaw_maxthrottle to 30%. It could probably go even lower.

So I advice everyone to enter this in CLI:

set tri_dynamic_yaw_maxthrottle = 30
save

I’ll set it as a default for the next version when the CF 1.14 is out.

[lauka]

In attempt to fix the throttle cut tumbling issue, yesterday I played around with a feature that limits the speed that the throttle can be cut. I did this just to see how slow the speed needs to be to avoid the nasty effect. I got down to 1000 / sec (1 second to cut the throttle), the tumbling issue was almost gone but this produced an unflyable floaty feeling. The motor braking force is just too much for the FW to correct when in FFF.

I’m out of ideas how to fix this. If anyone has some ideas, please share them.

Please see this post for reference of what I’m talking about: http://rcexplorer.se/forums/topic/debugging-the-tricopter-mini-racer/page/58/#post-28743

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