Hi All,

I have flown my quad 12 times now, using the stock pid param as per 3.2.1

I get ~25min per flight with small HD Tube nose-mounted FPV cam.

I now want to attempt Auto-tune to optimize the rig.

 I don't think I am experienced enough to do PID tuning manually.

However, I read somewhere around that Auto-tune can fail on bigger, heavier quads, with low kv motors.

My build is based on the Tarot 650 Sport Quad Frame (X-config)

FC - PixHawk (3.2.1)

Motors - Tarot 4114  320kv    

Props - CF 1550

ESC - HobbyWing Xrotor 40A

Batt - 8AH 6S

AUW : 3kg

1) I would like to know if Auto-tune can be done successfully on this build.

2) Do you recommend that I first upgrade to 3.3.3

Thank you for your valuable comments.

Regards,

Gerhard

Cape Town, South Africa

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what exactly are your concern, and what is it based on ? - untested sync issues in your motors/ESC's or the tuning loop itself ?

Hi Andre,

 I have no experience with pixhawk FC,  this is in fact the first for me into the UAV-tech.

I realize that most forum-users are highly-experienced already the PixHawk and

UAVs in general.  Hence me touching base on others' experience and advise.

So, it is not that I am having problems, I just need some confirmation from the forum

 that auto-tune is suitable for my particular set-up, prior to doing ATun.

IMHO  the  construction and components are well-placed and mounted properly.

 The Vibes Graph appear to be within acceptable limits, as I interpret it.

Currently, I am using the default PID's as per 3.2.1.

I have tested > AltH, PosH, Loiter, RTL, Land > The R&P sticks appears to be

responsive, so I deem it ' working ok ', but maybe not optimized.

e.g. > In PosH, light tumble breeze, it is not really solid in the air though, drifting of position.

I recon it is because the FC flight params eg PIDs has not been optimized? 

I don't want to adjust the PIDs manually at this time.

since I don't have enough experience to 'understand' how bad, or good, my adjustment would

render the craft. (At the same time I am apprehensive that, by doing manual adjustment, via MP, then Try and Fly, I may damage the rig during flying, which, for me was an expensive build

and most of the frame parts are not available locally ) For me rather baby-steps....

I googled several vid/advice re PID adjustment how-to's

Received valuable input from others on the forum.

Read the wiki on ATun

At this time, since I lack experience and confidence to do a manual PID tuning, I am opting for ATun.

So this will be my next step.

Just to confirm -

1) I assume one have to do ATun in rather windless conditions?

2) Can one do it in a big hall where there is no wind?

3) From my understanding,  ATun does not make use of the GPS, thus 2)

4) Since I am on 3.2.1 would you recommend me to upgrade to the latest stable FW 3.3.3?? prior to ATun

In a perfect world I would have liked to make contact with a local fellow-hobbyist in my area whom

I can contact and touch sides with, but at this time my current resources are DIY forums, the wiki,

and the like, to learn and explore the interesting world of UAV.

Anyway, thank you for your comments and interest in my posting here.

Regards,

Gerhard

Cape Town, South Africa

1: yes, little to no is best, as long it's not turbulent and just steady, a few m/s is fine.

2: depending on size of hall and UAV, you will always generate your own airflow in there after a while, and have less space - and no GPS.

3: no autotune is done in alt-hold mode, it's not using GPS position in the traditional way, but uses it for AHRS, read and do as http://ardupilot.org/copter/docs/indoor-flying.html says if flying indoors.

4: yes, do upgrade. - and read all releasenotes for each version between (https://github.com/diydrones/ardupilot/blob/master/ArduCopter/Relea...)

Hi All,

Thank you for your valuable input re ATun etc.

Steps I am going to take includes -

Upgrade to latest stable FW

After setting the default params and fly in stbz m

Fly in AltH to record frame vibes.

If this is within the params, I am going to attempt ATun.

I will keep you posted on my progress.

Once again, thank you DIY.

Regards,

Gerhard

Cape Town

Hi Gerhard, you 'should' be OK, but you would want to test the motors on the ground first.  I fly a 650 sport as well but I use sunnysky 3508 580kv motors and hobbyking afro 20a eSCs and 1550 props, so you are quite a bit lower KV.  I've never had any desyncs in flight except when using active braking (don't do it!).  it's great that you can fly it successfully manually and I assume you haven't had any problems.

When I first build/try a quad I always take the props off and 'fly' it on the ground - first of course check the motors are all spinning the correct rotation and then I gun the throttle as fast as possible up and down and make sure they respond as expected.  Some people advise then strapping the quad down (tightly!) and repeating this with the props on but I've never felt comfortable doing that.  I then fly it in stabilize mode and when i'm happy it's reasonably stable in hover and gentle flight I then again gun the throttle up and down as quickly as I can many times as I can take, and also left and right and front and back as violently as possible.  All of these actions replicate as well as possible manually what autotune will do - very quick bursts of throttle on certain motors.  If these tests go well then at least you've done your best before invoking autotune, which has never gone wrong for me yet (touch wood!).

It's also very much worth looking at your ESC firmware.  Assuming you've got hobby*w*ing ESCs I know nothing about those personally, but they have a superb reputation.  Hobby*k*ing ESCs which I have less so :)  SimonK firmware is known to be prone to desyncs because it focuses more on fast throttle response which is what incurs desyncs on lower KV motors, so I changed to blheli immediately, which has smoothed throttle, and never had a problem although my motors constantly screech which tells me I must be near a desync.

Upgrade to latest 3.3 and give it a go, I would definitely do it outside over grass as it's a softer landing if something goes wrong!  The only desync I've ever had, when trying active braking, it nosedived hard into a tree and didn't damage anything at all except for a mast.  If I'd been inside a hall I suspect there would have been heavy damage to it.

Good luck :)

ur motors are under powered for a 15 inch prop. Esp if your using 4S. Not that it wont work but thats not an efficient set up..

Hi Tony,

If you are referring to my build, I am using 6S 8AH,

 which I believe is ample for my application.  (See the intro)

Regards,

Gerhard

no no Gerhard ur good. Very good. You wrote hobbyKING xrotor but i think you meant hobbyWING. those are awesome for low kv. 

I was replying to fnoop dog lol. 

Also i have the same ESC and i never failed auto tune. I have the same frame but different motors 380 KV from tarot. 

Hi Fnoop,

 Thank you for input and advice.

I have indeed checked and verified the points you mentioned, prior to my initial test-flight attempt.

And yes, I have flied successfully in stblz m, to date.... ;)

as well as AltH,PosH, Loi, performed RTL and Land.

I bought HobbyWing Xrotor, from what I understand their ESCs are pretty 'good'.

If the ESC 'desync' condition is indicated by ESC 'screeching' sound, at this time, particularly

from this morning's test result, I did not detect ESC desyncing.

I made further comments on this main topic thread, points relating to what you mentioned here.

Regards

Gerhard

Hi All,

It was a rather windless day here today, which is rare for Cape Town :)

 I grabbed the opportunity to test my craft again : 

FM > Stblz, AltH, PosH, Loiter, 360d Yaw L&R, Electric Landing Gear Up/Down.

The craft appears to be functioning correctly, without glitches, as I understand and experience the flight dynamics. (The craft is setup with the default PID's, as per 3.2.1 loaded, I did not alter any of these params)

In AltH I apply short duration full step P&R stick cmds,  it appears that the craft follows the R&P cmd, visually in the air, which was quite pleasing for me :)   I am going to have a look at the FC flight data graphs to have a look at the desR&P vs actR&P to see how that looked like.

My next step is to upgrade via MP to whatever the stable released ver of 3.3.3

Do various test-flights

Check vibes etc.

Then Atun, which would hopefully not cause any nosedives.... ;)

I will keep this topic thread posted on my progress.

btw, I have a nose-mounted hd cam. 

 It was nice to see Table Mountain in the distance :)

Thanks all!

Regards,

Gerhard

info@skyfly.co.za

Ahhh Tony,

 Thanks for pointing out my 'typo' spec mistake..... 

    >> indeed HobbyWing...... of course :)

I also use the Tarot brand 4114 320kv motors.

  The motors really sound great when they spin-up.

I guess I can't edit the initial topic thread to refect the correct build info?

  I will add the correction in the main topic thread though.

I am so glad to here there are more DIY'ers using the same frame and components

 which I am using  :)))

In hindsight, I think I should have opted for higher  kv motors,

 I say this without motivation though.

btw, which brand/model motors and Batts are you using?

 I am using the GensAce Tattu 6S 8AH

What is your overview and experience with this frame/components and PixHawk?

I am using the Taranis X9D+ radio at this time.

Regards,

Gerhard

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