Oscillations
Hello All,
Got a new rudder/elevator easystar back in the air today, and when I switched to fly-by-wire it didn't roll-over and dive! Making progress.
The stabilization appears to be working, but it's over-correcting itself. The nose wobbles in a 12" circle when activated.
I've read through the manual, and searched on here, and it appears that I need to learn more about PID gains to reduce pitch and roll.
This is going to be my next stab in the dark. In looking at other *.h files, what I'm trying doesn't appear to be necessary, but it's where the docs seem to be pointing me.
pitch_P, pitch_I
roll_P, roll_I
Do the sensors have to be completely level at startup? ie: can the plane be leaning on a wingtip? I'm using FMA XY sensors for my XY and Z, and they're as level and plumb as I can make them on velcro tape.
Thanks for any tips!
//ROLL GAINS
//5-1
#define roll_abs .2 //Set point absolute...(Not Used)
//5-3
#define roll_P .17 //roll PID proportional .35 stock
//5-3
#define roll_I .17 //roll PID integrator .35 stock
//5-4
#define roll_min -25 //PID output limit in servo degrees
//5-5
#define roll_max 25 //PID output limit in servo degrees
//5-6
#define roll_Integrator_max 10 //Limit the integrator, to avoid overshoots
//5-7
#define roll_Integrator_min -10
//PITCH GAINS
//6-1
#define pitch_P .32 //Pitch Proportional .65 stock
//6-2
#define pitch_I .17 //Pitch integrator .32 stock
//6-3
#define pitch_min -25 //Pitch limits
//6-4
#define pitch_max 25
//6-5
#define pitch_Integrator_max 10 //Pitch integrator limits
//6-6
#define pitch_Integrator_min -10
//6-7
#define PITCH_COMP .30 //<------Very important, Pitch compensation vs. Roll bank angle.
Got a new rudder/elevator easystar back in the air today, and when I switched to fly-by-wire it didn't roll-over and dive! Making progress.
The stabilization appears to be working, but it's over-correcting itself. The nose wobbles in a 12" circle when activated.
I've read through the manual, and searched on here, and it appears that I need to learn more about PID gains to reduce pitch and roll.
This is going to be my next stab in the dark. In looking at other *.h files, what I'm trying doesn't appear to be necessary, but it's where the docs seem to be pointing me.
pitch_P, pitch_I
roll_P, roll_I
Do the sensors have to be completely level at startup? ie: can the plane be leaning on a wingtip? I'm using FMA XY sensors for my XY and Z, and they're as level and plumb as I can make them on velcro tape.
Thanks for any tips!
//ROLL GAINS
//5-1
#define roll_abs .2 //Set point absolute...(Not Used)
//5-3
#define roll_P .17 //roll PID proportional .35 stock
//5-3
#define roll_I .17 //roll PID integrator .35 stock
//5-4
#define roll_min -25 //PID output limit in servo degrees
//5-5
#define roll_max 25 //PID output limit in servo degrees
//5-6
#define roll_Integrator_max 10 //Limit the integrator, to avoid overshoots
//5-7
#define roll_Integrator_min -10
//PITCH GAINS
//6-1
#define pitch_P .32 //Pitch Proportional .65 stock
//6-2
#define pitch_I .17 //Pitch integrator .32 stock
//6-3
#define pitch_min -25 //Pitch limits
//6-4
#define pitch_max 25
//6-5
#define pitch_Integrator_max 10 //Pitch integrator limits
//6-6
#define pitch_Integrator_min -10
//6-7
#define PITCH_COMP .30 //<------Very important, Pitch compensation vs. Roll bank angle.
Replies to This Discussion
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Permalink Reply by John C. on -
Honestly, I'm not sure if my Z sensor is oriented correctly.
With the FMA XY sensor as the Z, how should it be set? You can see how mine is currently in this picture.
-
Permalink Reply by Richard Green on
-
John,
I tested my XY sensor that I am using as a z with the Infraredboards software from the google repository. From this I discovered that the sensors that were working were the ones on the P-P axis marked on the sensor. I also found that covering the sensor nearest the P next to the FMA logo (does this still make sense?) with my hand gave the highest reading. Therefore I have, rightly or wrongly placed my sensor in exactly the same place as yours but rotated 90 Deg anticlockwise when looking at the plane.
I have just installed the pitot tube in the nose and have not flown it yet so whether I am correct remains to be seen.
Richard
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Permalink Reply by John C. on
-
So, FMA logo down, with the plug in the top left corner, looking at the sensor flat?
I just re-tested mine, and found it to have the exact same readout as yours. I'll turn it that way and give her a try here in a couple of hours.
Thanks for the reply!
-
Permalink Reply by Riccardo Kuebler on -
Not shure (never tried) but it seems that it doesn't matter direction. AP during startup recognize it.
-
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Permalink Reply by John C. on
-
OOOOOoooooooK....I turned the sensor the right way. (Duh)
Still didn't want to come around too easily, so then I bumped the roll_P to .35 and pitch_P to .65, both I's at .0.
Did a fly-by-wire flight, and it's MUCH more stable than it was with the same P settings when the sensor was turned wrong. Also responded much better to stick input.
Put the GPS in, and still didn't want to come around very well. Still need to test it some more. -
-
Permalink Reply by Riccardo Kuebler on
-
Here is my rudder mod and were I placed the FMA XY sensor.
The red portion is what I added to the original one.
-
Permalink Reply by John C. on
-
Alright, got another flight in. Still doesn't want to come around for RTL or waypoints. Oscillations were solved, so I'm going to start a new thread.
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