Manual Tuning of Sub¶
Sub has several control mechanisms for axis stabilization in certain modes, manuvering speeds, angle limits, etc.
Axis Stabilization¶
Manual tuning may be required to provide maximum stabilization without oscillation in the Roll,Pitch, and Yaw axes. Depending on frame configuration and mode, Sub can provide attitude/heading stabilization in those axes, but tuning of their attitude controllers may be required to obtain the optimum stabilization, ie. rapid approach to rate/angle targets with minimal overshoot or oscillation).
This can be accomplished by manually adjusting each axis’ attitude rate and angle controllers’ parameter values.
The following rate controller parameters are adjusted:
Roll |
Pitch |
YAW |
|---|---|---|
Note
depending on frame type, roll and pitch axis control may not be implemented, so tuning is obviously unnecessary. Yaw control is always implemented in Sub frames.
For each axis:
If the vehicle already oscillates in an axis, first lower the P, D, and I terms in 50% steps until stable, before starting manual tuning.
When oscillations start do not make large or sudden stick inputs, and reduce the parameter increased as soon as possible.
Increase the D term in steps of 50% until oscillation is observed
Reduce the D term in steps of 10% until the oscillation disappears
Reduce the D term by a further 25%
Increase the P term in steps of 50% until oscillation is observed
Reduce the P term in steps of 10% until the oscillation disappears
Reduce the P term by a further 25%
Each time the P term is changed set the I term to approximately 3/4 the P term. Those parameters can be changed on the surface, and preferably when disarmed.
The other ATC_ rarely need changing from the defaults.
Maximum Attitude Angle Limits¶
These can be changed with:
Speeds¶
Several parameters impact speed or speed limits:
Depth Control¶
Vertical position holding modes (ALT_HOLD,etc.) have these primary tuning parameters, which can be lowered if depth oscillation occurs: