Re: [Paparazzi-devel] Copter tuning/setup cookbook step-by-step

[bshaot]

Hi SilaS:
   When I tunning my plane,I tied up the plane`s nose and tail,Let aircraft
can only roll.And in setting,put Parameters to be unrelated to roll tobe
Minimum,then you can try to tunning roll PID follow this
step:http://wiki.paparazziuav.org/wiki/NPS.when you finish roll PID,the next
is Pitch...
Tuning the attitude control loop
Here we are going to use the simulator to demonstrate a way of tuning the
attitude control loop.
Restart your previous session
Set telemetry mode to "attitude_loop"
Display two real time plotter windows
In the first one, plot the field "m_phi" from the "STAB_ATTITUDE_int"
message. This is our estimation of roll angle. On top of that, plot the
field "phi" from the "STAB_ATTITUDE_REF_INT" message. This is our reference
roll angle, that is, the roll value we are trying to achieve.
In the second plotter, plot the fields "delta_a_fb" and "delta_a_ff". Those
are respectively the feedback and feedforward part of our roll command. The
sum of those two terms is what is used as roll command.The feedforward part
is the part used to follow our trajectory and the feedback part is the part
used to reject perturbations.
In "Settings", go to the "Att Loop" tab
We notice that the vehicle doesn't follow the step trajectory we are trying
to make him do accurately.
Start by setting the value of the proportional gain ('pgain_phi') to 1000
instead of 400. The vehicle now follows the trajectory faster but
overshoots. To prevent that, increase the value of the derivative gain
('dgain p') from 300 to 700.
If you look at the plotter where you're plotting the commands, you'll notice
that during steps, the feedback command has to work hard. This means that
our feedforward command is badly tuned, and namely not working hard enough.
Increase the value of the feedforward gain ('ddgain p') from 300 to 540.
You'll notice that now the feedback command has become marginal during the
steps. This is the right value for the gain. Anything bigger will make the
feedback command fight against the feedforward command during steps,
anything smaller will make the feedback command have to complement the
feedforward command.



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