Aircraft pitch-axis stability and command augmentation system

An aircraft pitch control system for use with an aircraft having a movable control column, the aircraft further including a position sensor for generating a signal representative of the control column position, the system comprising:

• (a) a first signal combiner having first and second inputs and an output;
• (b) a pitch command processor connected for receiving the column position signal and for supplying a feed-forward elevator command signal to the first input of the first signal combiner;
• (c) a commanded elevator response processor connected for receiving an input including the signal representative of the control column position and for generating an output including a signal representative of the commanded elevator response, the commanded elevator response signal embodying desired flight characteristics;
• (d) a computed elevator response processor for receiving inputs including signals representative of the aircraft normal acceleration, aircraft pitch rate, aircraft speed, and a reference speed;
• the computed elevator response processor generating an output signal representative of a computed elevator response according to current flight conditions;
• the computed elevator response being based upon at least the aircraft normal acceleration signal, the aircraft pitch rate signal, the aircraft speed signal, and the reference speed signal;
• (e) a second signal combiner connected for receiving the computed elevator response signal and the commanded elevator response signal and for generating an output signal representative of the difference between the computed elevator signal and the commanded elevator signal;
• and
• (f) an integrator connected for receiving the difference signal and for driving the difference signal to about zero, the integrator generating an output signal received by the second input to the first signal combiner;
• wherein the pitch command processor includes bias correction means connected for receiving the control column position signal and for supplying a corrected column position signal to the commanded elevator response processor as the signal representative of the position of the control column, the bias correction means for reducing bias in the control column position signal when the control column is in a neutral position.