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PID Settings English subtitles.
Translation by Totoff (Sorry for any mistake)
PID ? .. What's that ??
Hello Bledi
So here we are back on field to explain PID settings as previous session was dedicated to additional sensors
And Basic Settings were missing
Then, we gonna review basic settings this morning ...
.. the PID Settings.
So, first question is : "What are PID"
- In facts, PIDs are the factors that system will use to correct itself and fly "as expected"
It's needed for customizing electronics that will handle gyros & accelorometers as all components (motors, ESC ..) are slightly different
So the PID are factors that will make correction on input data from gyros and accelerometers and make a correlation with manual stick command to give adjusted instructions to motors.
As previous session, we're using android App "Multiwii configurator"
wich is running well on the release 2.0
and allow a Bluetooth connection on our HX4 Frame
and make quick modifications of PID without having to connect a laptop each time
Sooo.. What is the first thing to do ?
First of all, we gonna set "Gyro mode"
Cause we'll never have a decent stable mode if gyro mode is not setup properly
Then, the first factor to setup and maybe the most important is the "P"
that will define the level of correction needed
For example if you ask a 20 degrees angle with sticks and your model is only get a 18deg. inclination
we have a 2° to correct and P is the "Power" needed to correct this error. So P is an amount to correct error.
Do we need 10 or 0,1 ? So, Setting P is a question of finding the correct amount to correct initial error.
There is a common simple way to set P
Start with default values and lower the I setting (called Integral) to 0,010
and then raise P until the model start to wobble (show vibrations)
as we gonna show with our frame
We started with P=5.2 and we're now with P=15 and see how it behaves.
So ... Does it wobble ???
Yes it does (not very easy to see on video)
not very easy to see as this frame is naturally very stable
Then our P is too high !
You can see it's hard to stay stationnary (altitude hold)
(Note : Its easy to understand as because P is too high we go beyond needed correction at each cycle so it vibrates around the correct point)
Now we gonna seek to correct P value to eliminate wobbles
Then, we will lower our P value
until it stops wobble and get a value just a little bit lower.
As we're on a symetric Quad-X, we gonna have similar values for Pitch and Roll.
and we can modify values for both Pitch and Roll.
Wrinting Parameters with P=14
Let's see
We stille have wobbles but it's already better
Than we gonna lower again the P value until wobbles disappear
Here with P=12
it still wobbles a little bit ... Still some way to go
easy to see on Live, not very easy on video...
Anyway that's more and more light vibrations ..
we set P=11.5
Now, we have a very clean behaviour
No more vibrations
Setting of I value (Integral)
We gonna now setup the Integral parameter
If you look at our frame at this stage,
It naturally difts and it needs to be manually compensated
It is not stable (even if we're on gyro mode it shouldn't drift so much with neutral sticks and no wind)
Here, it drifts right and left
It means that if we have a constant low error, we need to correct it over time.
This is not as simple as P to define this value, it needs to be set higher until the behaviour seems correct. Not very easy...
Higher is the I value, smoother will be the commands of the frame
So Go to a Low I for Accro and Higher I for Video Shooting
Keep in Mind that I and P are in a Loop and are correlated. So if you change I value, you may need to modify slightly your P value
Here is a "special trick" that allow to see quickly if our I is too low.
For that we gonna create a static error by adding weight to one arm.
of course, bigger is the weight, higher would need to be your I
The aim is not to correct big weights but it should be heavy enougth to create a static error (Frame angle)
Let's see how it behaves ...
And it drifts slowly on the direction of the weight Needs manual correction
That can be corrected by raising the I
That's only "a trick" but it works quite well
Now I don't make any correction and you see there is almost no drifts.
We have a 200g weight on Quad's arm and it stay stable.
and it's due to our I value that corrects the error.
Here it' good but you may see some small wobbles are back on some movements
Then we gonna get back to P and lower it a little bit
Really needed as we're on low battery and wobbles are more important on a charged battery
Here with P lowered to 10.8 it's ok ! (Still in gyro mode !! )
Even near ground, frame behaviour is perfect
So Let's Set D ... D for Derivative !!
D is mainly of question of feeling with your model
So we make large movements
and see how you feel the behaviour of your model
If you feel that it doesn't come back fast enougth
then Raise D
if you feel it is too nervous
then lower D
Summary : Lower D to get smoother reactions Raise D to have more nervous reactions
- I really like it as it is set right now
and we have a D=0.35
Take care Raising D, is once again modifying the command loop and is similar to raise P.
So, if you raise D, you may have to lower P a little bit once again. (if you see wobbles coming back)
Here, behaviour is really sane and it can be controlled easilly.
Frame never goes beyond command.
Remember we're still in Gyro mode
so, we're commanding with angular speed. (Stick command is a rotation speed, not a angle)
it will not level automatically with stick centered, backward action is needed.
Setting YAW
Yaw is normally the easiest, if you see that there is no self rotation on yaw axis, you're already ok with default values
8,5 is normally ok for most of the quads.
Now, we're gonna switch to stable mode
So now, stick movements give an angle command to the drone. And it levels with stick centered.
Baro and compass are not active
we switch them on form the remote.
An here it is ... Stable as a rock !!! :)
Accro Mode Settings
(As you can see, this frame can be either used for accro or video shooting easily)
We're still with same PID settings but, we changed the RC Rate
So, What is "RC Rate" ?
We have in fact Pitch Roll Rate that is a modifying factor for PID in correlation of the requested power
That will make the quad a little bit less stable when high power is needed. Wich is helpfull for example in "looping figures"
We also have the RC Rate (located near Expo) that define the maximum rotation speed of the drone
You can play with Both parameters. Raising rotation speed of drone and reducing stability with few PitchRoll Rate
Now that you know how to setup PID, No more excuse to keep default Value ...
.... or you'd have to pay a forfeit !! :-)
- Thanks for watching !!!!!! -