@bkueang and me realized that on every frame we tune the integral gain for
the roll and pitch rate controller is much too low. Usually it needs to be
increased to 0.3 or even 0.4 to have better "locked in" flight performance
and 0.2 seems like a good compromise for a safe default.
A low gyro cutoff is needed for most medium/large size drones as the structural natural and blade-pass frequencies are low.
A higher value is still desirable for small platforms surch as racers
or well isolated autopilots and should be tuned by the user.
Specific values for config files are untouched.
The cutoff filter for the D term is disabled here as the required
cutoff frequency for the default D term of the rate controller is higher
than the gyro cutoff. In that case, enabling the D term cutoff would
just add some undesired phase lag to the derivative.
It scales the yawspeed setpoint arbitrarily by default with 0.5.
This makes no sense because when you give a setpoint of 1rad/s then
you expect the setpoint to get executed. If you want manual yawspeed
response to be less agressive on the stick use the scaling parameter
for the stick MPC_MAN_Y_MAX.
Because the parameter does not make sense from a control theory
perspective. Either you have a gain with the unit 1/s or an inverse
gain or time constant with the unit s. But the time constant parameter
was neither bound to any exact unit nor did it apply instead of a gain.
Rather it adjusted multiple gains from rate and attitude control
according to an arbitrary scale. This can only by accident lead to
good tuning.
tested on at least 5 different vehicles, including AeroFC. The values
should be conservative, good setups (with low vibrations) can increase
these values even further.
increasing IMU_GYRO_CUTOFF allows for better tuning gains (increased P).
If you want to go to the limit of what the vehicle can do, you need to be
able to set it so large that it is guaranteed that it's never limited by
software.
Tests showed that it's not a problem to increase it to very high numbers.
360 is too fast if you just want to hover. Next step is to add expo(),
so that we still have fine-grained control at the center and high rates
at the edges.
Use reporting from the motor mixer to only restrict integrator growth when it will result in increased saturation of the control axis concerned.
Enable absolute integrator limits to be set by parameter
Hamish Willee