Steady state differential roll moment control with automated differential lateral control

A method for controlling a differential rotor roll moment for a coaxial helicopter with rigid rotors, comprising:

• receiving, with a processor, a signal indicative of a displacement command from a controller;
• receiving, with the processor via a sensor, one or more signals indicative of a longitudinal velocity, an angular velocity of one or more rotors and an air density ratio for the helicopter;
• determining, with the processor, a ganged collective mixing command in response to the receiving of the displacement command;
• determining, with the processor, a rotor advance ratio as a function of the longitudinal velocity and the angular velocity;
• determining, with the processor, a corrective differential lateral cyclic command by determining coefficients from the ganged collective mixing command, applying the coefficients to the rotor advance ratio to obtain a value and normalizing the value by the air density ratio;
• and
• applying, with the processor, the corrective differential lateral cyclic command to the rigid rotors to control the differential rotor roll moment to a desired value.