Flew a rather sucessfull mission this weekend, need some more tuning tho. I have a few questuions :



1. I have the t-logs, that are saved automatically, but wanted to download the APM log as well. When I connect, there are NO logs. When I do a Dump 0 , there are no logs to download., any Idea whats up with this? (Had this problem before)


2. I am busy tuning the NAV-ROLL Pid settings ONLY. Picture 2 waypoints placed 1000m apart. The plane is flying from WP1 to WP2.


Stock Pid values gave me a pronounced s-shaped track, imagine a high frequency sine wave.


I altered the values to :


P : 0.2

I 0.02

D 0.5


and now I am getting a much better track, but still a sine wave flight pattern between the waypoints, albeit a "low frequency" sine wave this time.


Any Suggestions on better PID values?


I can post my t-log files if that will help. anyone out ther with a +- 3m wingspan plane that can send me their config file??


3. Please PLEASE PLEASE Jason can we have a dynamic tune function in arduPLANE too (if it is not there allready)





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Take a look at: "quest-for-the-perfect-flight-path" .

Check your Xtrack gain value.  Older versions of APM firmware and Mission planner divided the value by 100.

They don't now so the old value of 150 is way too high.

My Telemaster PIDs are in that thread.


I found that snaking or 'sine wave' flight paths can be the result of too high an Xtrack gain.  The newer versions of APM and Mission Planner accept a value between 0 and 10.  It was 0 to 100.

thanx Irvin


Most helpful info!

I will post my log files here in the morning so you can replay them to see the snake in action.

AFAIK my xtrack gain was set to 100, thinking 100%, good to know about the 0-10 thing.


youve obviously been doing some PID tuning, tell me,


when changing a value from say 0.5, I am never sure if changing it to 0.6 is a 10% increase (if the max is 1), or a 0.001% change (if the max is say 100). How do I know HOW MUCH to change it by?






I have made .1 incremental changes to 'P' values, during flight, with no adverse problems.

I set up a square pattern with enough waypoints to go for 3 or 4 laps.  During the flight, I make a change then observe the flight path through at least 2 corners and 2 straight legs to see if there is improvement or not.  If I run out of waypoints I just hit the 'Restart Mission' button.

At this point I am only changing Nav values.  (The Servo values were adjusted with FBW_A flights.)

We hope to make a 7 pass photo grid flight tomorrow.

Cool.Took note of your figures, especially xtrack gain, and will try them this weekend, weather permitting.

I have attached my logs if anyone is interested (Chris?) to take a peek and give a suggestion or 2.


Last week's settings looked like this :


Example of the Snake :

this was BEFORE we started tuning, by the end of the session it looked quite a bit better, ( well, same amplitude, but less frequency, if you get my drift.) so we carry on...


Pretty sure I tried it with a low Xtrack gain value, but will double check this weekend.


BTW, is there a big plane on the HIL simulator that behaves like your Telemaster? Would be nice to play with values there. Would you say simulating is an important component of mastering this thing?

Trying to decide if I should lay out more cash for X-plane or flightgear.







These logs are actually fun to watch at speed 7x


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