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Help me fine tune my governor using telemetry data

Posted: Thu 25. Aug 2016 15:21:05
by jgiannakas
Hi all

Would love your collective help in helping me fine tune my governor so I get the best performance out of my Goblin Black Thunder. I've installed jLog and connected to my HW130a V4 and have managed to get detailed telemetry data so hopefully someone can help me fine tune it or tell me if its as good as it can get :)

I've been performing some sloppy tic tocs as can be seen in the telemetry screen below:
Tic Toc Full.jpg
If I zoom in you can see a bit more detail:
Tic Toc.jpg
Lets take a "Tic" cycle at 8:50. As I am unloading the head, the gov drops to 89% throttle. When I reach inverted and punch the collective it jumps to 97% throttle. Also pushing up the current to 86.9A from circa 24 amps hover current and 26A when I was flipping it backwards.

At that stage I notice the RPM dropping from a 21160(motor rpm) / 1977 rotor RPM to 20760 motor/1940 rotor before jumping back up to 21730 / 2030 rpm. At that point throttle starts to drop from 97% back to normal 89%.

So Im experiencing about a 30-50 head RPM drop followed by a 100rpm "correction.

Also in the below pitch pump:
pitch pump full.jpg
I start from 21797/2037 head RPM. Then drops to 20283/1895 rpm. I can see the throttle increasing when the RPM are at 21419/2001 (i.e. after it has dropped by 30rpm or so but that could just be normal fluctuation of the rotor head) from a 82% linearly to 91.9% at the lowest point in the RPM - 20270/1894. It then gradually reduces as the headspeed rises to 22563/2108 rpm but it does not go down quick enough as the RPM increase hence the overshoot. So it ramps up quick (or slow??) enough to loose about 140rpm then overshoots by about 70rpm or so.

My settings are:
Response: 6
Holding performance: 4
Target RPM: 2000 (or so)

Should I increase governor response and reduce holding performance? I havent done any long load tests so havent really tested the holding performance but during the tic tocs it did not loose on average any headspeed.

Re: Help me fine tune my governor using telemetry data

Posted: Thu 25. Aug 2016 15:26:44
by jgiannakas
Here's the Pitch Pump zoomed in:
pitch pump z.jpg
Also I did get quite a few noisy RPM signal flags in the log, but the Gov seemed to work OK so I'm just going to ignore this for now :)

Re: Help me fine tune my governor using telemetry data

Posted: Fri 26. Aug 2016 9:41:56
by ZeXx86
What you can try is to increase gov response and decrease holding performance, both by one.

You can also try second option, gov response to 4, holding performance to 3.
Can you see a sensor noise with this settings?

If RPM is holding so that there is variation of 50 RPM or less, it is good.

Re: Help me fine tune my governor using telemetry data

Posted: Fri 26. Aug 2016 10:05:05
by jgiannakas
Perfect I'll try both this morning and let you know. Thank you!!

Re: Help me fine tune my governor using telemetry data

Posted: Fri 26. Aug 2016 14:29:38
by jgiannakas
Ok so I've tried the gov response at 7 and holding at 3. The RPM holding power was MUCH better. It fluctuated under 70 rpm during tic tocs. See below. The only indication there was a tic toc happening is the surge in Amps!
Tic Toc tuned.jpg
However I did notice that my tail was much more prone to wagging. I had to drop tail gain a few points to stop it and it was still complaining during my last flight in FFF, loops, tic tocs and side flips. I am guessing its the governor response causing the tail to twitch - see the graphs below. Both are from a 25sec or so flight window.

With 6 / 4 - notice how smooth the throttle % is
Throttle variance old.jpg
With 7 / 3 - notice how much more the throttle % varies
Throttle variance.jpg

I might revert to governor response to 6 but also drop holding performance to 3. Thoughts? Would this make sense as would it make it over-speed less bit still hold relatively OK?

Or would you advise to tune out the tail issue by reducing gains? Im currently running 58% with 1.3 multiplier, 180 piro consistency, 1 rudder delay. Servo is BK7006HV (coreless, at 7.5V with 0.032 sec/60). Heli is Goblin Black Thunder, Xnova 4525 560.

Oh and I did try with 5 & 4 response and holding but the performance was not good at all so did not fly the whole flight :D