COMPENSATION FOR ROTORCRAFT PITCH AXIS CONTROL SATURATION

A control system for small unmanned rotorcraft compensates for vehicle pitch control saturation caused by the need for sudden vehicle pitch attitude correction, in turn often caused by wind gusts. The rotorcraft has a pitch-variable rotor system responsive to a vehicle pitch servo command for cyclically controlling rotor pitch and responsive to a collective servo command for collectively controlling rotor pitch. A compensating signal derived from the unlimited vehicle pitch servo command signal is cross-connected to the unlimited collective servo command signal to compensate for pitch control saturation, typically by reducing the magnitude of the resulting collective servo command signal. The compensating signal is derived by passing the unlimited vehicle pitch servo command signal through a dead band which responds as the signal approaches saturation and by preferably also then providing high and low frequency shaping to that signal.