Add a 2nd-order critically-damped attitude reference model whose angular-velocity output is fed forward onto the rate setpoint, removing the steady-state ramp-tracking lag of the pure-P attitude law. The model uses an exact closed-form discretisation, so it is unconditionally stable.
Parameters:
- MC_REF_W_N reference-model bandwidth [rad/s]
- MC_REF_FF feedforward gain [0..1]; 0 disables the anticipation
- MC_REF_FF_MAX per-axis feedforward saturation [deg/s]
The commanded yaw rate is always fed forward at unity (it is a setpoint, not a model prediction), so MC_REF_FF scales only the error-driven anticipation and MC_REF_FF=0 is the exact legacy pure-P law. Shipped disabled by default to avoid changing behaviour on existing platforms; enable per-airframe. Includes docs and the updated controller diagram.