A method of stabilizing a jet-powered tri-mode aircraft as the aircraft travels in a helicopter mode, a compound mode, and a fixed-wing mode is disclosed. The method includes receiving a plurality of velocity vector component values and velocity vector commands derived from either (1) a number of pilot operated controllers or (2) a commanded array of waypoints, which are used for fully automated flights, and a rotor speed reference value, which is decreased with increasing forward speed to unload the rotor, thereby permitting conditions for stopping the rotor in flight. Stabilization of the commanded velocity vector is achieved in all modes of flight using blended combinations of rotor swashplate controls and aerodynamic controls such as elevons, canards, rudders, and a horizontal tail. Stabilization to the commanded velocity vector includes a plurality of control constraints applied to the pilot stick controllers that prevent penetration of envelope limits.

Enhanced flight control systems and methods for a jet powered tri-mode aircraft

A flight control system includes a lift control algorithm which selectively communicates with the pitch command of the flight system control algorithm. The lift control algorithm selects the proper control commands to coordinate an effective transition between hover and forward flight. The most efficient vehicle pitch during transition is thereby automatically generated so that sufficient lift and control throughout the transition between rotor borne and wing borne flight.

Flight control system for a hybrid aircraft in the lift axis

The invention is embodied in a method of integrating kinematics equations for updating a set of vehicle attitude angles of a vehicle using 3-dimensional angular velocities of the vehicle, which includes computing an integrating factor matrix from quantities corresponding to the 3-dimensional angular velocities, computing a total integrated angular rate from the quantities corresponding to a 3-dimensional angular velocities, computing a state transition matrix as a sum of (a) a first complementary function of the total integrated angular rate and (b) the integrating factor matrix multiplied by a second complementary function of the total integrated angular rate, and updating the set of vehicle attitude angles using the state transition matrix. Preferably, the method further includes computing a quanternion vector from the quantities corresponding to the 3-dimensional angular velocities, in which case the updating of the set of vehicle attitude angles using the state transition matrix is carried out by (a) updating the quanternion vector by multiplying the quanternion vector by the state transition matrix to produce an updated quanternion vector and (b) computing an updated set of vehicle attitude angles from the updated quanternion vector. The first and second trigonometric functions are complementary, such as a sine and a cosine. The quantities corresponding to the 3-dimensional angular velocities include respective averages of the 3-dimensional angular velocities over plural time frames. The updating of the quanternion vector preserves the norm of the vector, whereby the updated set of vehicle attitude angles are virtually error-free.

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Closed-form integrator for the quaternion (euler angle) kinematics equations

A system for performing feed-forward anticipation of rotor torque demand on a helicopter engine is disclosed which includes a flight control computer adapted and configured to predict the total torque required at the main and tail rotors of the helicopter, and an engine fuel control system adapted and configured to compute the rate of change of the total torque, convert the rate of change of the total torque to an engine acceleration/deceleration rate, and obtain a demanded engine acceleration/deceleration rate therefrom.

Rotor torque anticipator

A main rotor system of an aircraft is provided including a first rotor coupled to a transmission and configured to rotate about an axis in a first direction. A second rotor is similarly coupled to the transmission and is configured to rotate about the axis in a second direction. At least the first rotor includes an individual blade control system (IBCS) configured to adjust a pitch of each of a plurality of blade of the first rotor independently. A standpipe is fixedly attached to the aircraft. The standpipe is arranged such that the first rotor and the second rotor rotate relative to the standpipe. At least one slip ring is configured to transmit electrical power and/or a control signal to the at least one IBCS.

Swashplateless coaxial rotary wing aircraft

An apparatus for compensating for spatial phase angle phase errors in the flapping angle oscillations of a rotor blade is disclosed. The apparatus receives a measured aircraft roll and a measured aircraft pitch. Gyroscopic moments resulting from these measured rolls and pitches are determined, and compensating gyroscopic moments are then generated and summed with commanded pitch and roll accelerations. Flapping angle phase lags of the rotor blade swashplate are added to the summed signals to cancel any flapping angle phase leads, caused by changes in aircraft or rotor blade speed caused by installation configurations of the rotor blade swashplate.

Stephen S. Osder

Papers

Rotor blade swashplate-axis rotation and gyroscopic moments compensator