United Technologies Corporation

Joseph A Post

Phillip J Gold

Lorren Stiles

A vertical control system for a rotary winged aircraft receives inputs from a displacement collective stick and a sidearm controller. The system provides a set point for the vertical rate of change of the helicopter as a function of a vertical lift command signal from the sidearm controller. The set point is used as a reference for an altitude rate of change feedback path, and an integrated value of the set point is used for an altitude feedback path. The set point is also input to a feedforward control path having an inverse vehicle model to provide a command signal indicative of the command for aircraft collective pitch necessary to achieve the desired set point. Signals from all three paths (i.e., the altitude rate of change feedback path, the altitude feedback path, and the feedforward path) are summed to provide a signal to backdrive the displacement collective which controls main rotor collective pitch.

Vertical control system for rotary wing aircraft

A ground-plane-referenced, acceleration signal 2 and Doppler velocity signal 56 are utilized by a complementary filter 6 to provide a complementary velocity signal 8 which is transformed 60 to an inertial coordinate referenced velocity signal 62 utilized in combination with a GPS position signal 56 by a complementary filter 68 to provide a complementary, position error signal 130 that is transformed to a ground-plane-referenced, position error signal 168 and summed with a wind speed signal 196 calculated from the difference between air speed 200 and the aforementioned complementary velocity signal 8 to provide a pitch command signal 202. A similar system is utilized to provide a roll command signal. The system is gated by signals 100, 176 which are determinative of the aircraft meeting predetermined flight conditions 250-262.

Hover position hold system for rotary winged aircraft

A control arrangement for use in conjunction with a flight control computer operating in response to various input signals including those received from a collective stick to control the flight regime of a helicopter, which is operative for causing the helicopter to perform bob-up and bob-down maneuvers, includes a circuitry which generates a first control signal when the helicopter is to perform a bob-up maneuver from its instantaneous altitude to a higher altitude, stores data descriptive of at least one instantaneous altitude at the time of commencement of the first control signal; issues in response to the first control signal, an ascent command signal representative of a helicopter ascent at a maximum permissible ascent rate; generates a second control signal when the helicopter is to perform a bob-down maneuver from the higher altitude to that stored in the storing means; issues, in response to the second control signal, a descent command signal representative of a helicopter descent at a maximum permissible descent rate; and supplies the respective one of the ascent and descent command signals as an additional input signal to the flight control computer for use in controlling the flight regime of the helicopter in accordance therewith.

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Burke, VA, United States of America

Joseph A Post