United Technologies Corporation

Sikorsky Aircraft Corporation

Donald W Fowler

Nicholas D Lappos

Douglas H Clelford

James B Dryfoos

James F Keller

Pengju Kang

Harshad S Sane

Derek H Geiger

Claude G Matalanis

Kenneth C Arifian

Anil Mehra

Muhammad Emadul Hasan

Lan Hoang

Stephen P Lee

Joan A Edwards

Sean J O'Connor

Ronald S Doeppner

Raymond J Brand

Derek Geiger

A rotary wing aircraft includes a rotor assembly includes a rotor sensor generating a rotor sensor time domain signal; a rotor transform module converting the rotor sensor time domain signal to a rotor sensor frequency domain signal; and a rotor transceiver for transmitting the rotor sensor frequency domain signal over a transfer medium; an airframe assembly including: an airframe transceiver receiving the rotor sensor frequency domain signal; and an airframe transform module converting the rotor sensor frequency domain signal to the rotor sensor time domain signal. Signals from the airframe assembly may also be converted to the frequency domain prior to transfer over the transfer medium to the rotor assembly.

Harmonic data transfer in rotary wing aircraft

A system and method to facilitate approach of a VTOL aircraft to an offshore facility includes inputting a waypoint for a landing platform of an offshore facility into an aircraft module, inputting an offset distance from the landing platform into the aircraft module, inputting a minimum descent height into an aircraft module, and inputting a final approach inbound course toward the landing platform into the aircraft module.

Module for integrated approach to an offshore facility

A flight control system and method includes a control loop control law to bias the collective stick toward a trim reference position with a motor and generate a force gradient with a clutch.

Flight control system for rotary wing aircraft

An integrated fire and flight control (IFFC) system determines a ballistic firing solution based on the position of targets relative to a helicopter and also based on the type of weapons to be fired. An elevation command is determined based on the required change in helicopter attitude to achieve the ballistic firing solution that, combined with the estimated time required to perform the aim and release of weapons, provides an estimate of deceleration and velocity loss that will occur. A forward acceleration and velocity profile is determined based on the desire to make a symmetrical maneuver sequence involving a nose down acceleration to achieve the acceleration and velocity profile that will be canceled by the subsequent deceleration and velocity loss during the pitch up maneuver to the ballistic firing solution. The forward acceleration and velocity profile is used to provide a pilot with a forward acceleration command that directs the pilot to fly a nose down attitude until the required forward acceleration and velocity profile is achieved. Alternatively, the acceleration profile is coupled to a flight control wherein a pre-launch maneuver feedforward command signal is summed with a side arm controller control command signal as the primary input to a rotor mixing function and a pre-launch commanded rate signal is summed with a side arm controller commanded rate signal to provide the primary input to an automatic flight control system, to thereby automatically control the aircraft to assume an attitude necessary to achieve the desired forward acceleration and velocity profile. A terminal phase maneuver is calculated to thereby return the aircraft to the previous attitude, velocity hold, hover hold or position hold condition prior to commencement of the pre-launch maneuver.

Helicopter integrated fire and flight control having a pre-launch and

A fire control system (55) azimuth command and elevation command provides a flight control system attitude reference in response to operation of the flight control system in a coupled aiming mode. The coupled aiming mode is engaged in response to the continuous operation of a pilot switch (920) the azimuth command and elevation command being below respective threshold magnitudes (940, 941), and the operation of the fire control system (55). During operation in the coupled aiming mode, the azimuth command and elevation command replace the yaw attitude feedback error signal and pitch attitude error signal, respectively, as the aircraft attitude reference. During integration of the fire control system and the flight control system, the flight control system is made less sensitive to small pilot command stick inputs below a stick input threshold magnitude, so that small or inadvertent pilot commanded yaw and pitch maneuvers will not affect the yaw and pitch attitude reference commanded by the fire control system azimuth and elevation commands. However, intended pilot commanded yaw and pitch maneuvers (70) maintain full authority at all times.

Helicopter integrated fire and flight control having azimuth and pitch

During operation of an integrated fire and flight control (IFFC) system in a coupled aiming mode, the occurrence of a weapon (172), weapon mount (145) or sensor (146) reaching a constraint limit (210) indices a fade-in of a constraint limiting axis command signal (140) for a respective attitude axis as the aircraft attitude reference, replacing the flight control system attitude feedback error signal (111) for the respective attitude axis. The constraint limiting axis command signals provide the aircraft attitude reference only while the pilot manually depresses and holds an enable switch (920). The pilot command stick input (90) remains the primary input to the IFFC system to thereby provide override capability for pilot command maneuvers.

Helicopter integrated fire and flight control having constraint limiting

During operation of a flight control system in a coordinated area bombing mode, one pair in a group of pairs of fire control azimuth coordinate error signal and elevation coordinate error signals are faded-in as the aircraft yaw attitude reference and pitch attitude reference, respectively. Each pair is respectively indicative of the change in aircraft yaw attitude and pitch attitude for an aircraft reference axis to be aligned with an aiming line of sight. The aiming line of sight corresponds to a target location within a selected target area. A firing signal is provided in response to both the azimuth and elevation coordinate error signals being below respective threshold magnitudes, and the next pair in the group of pairs of azimuth and elevation coordinate error signals provide the aircraft attitude reference. A selected weapon is fired in response to the firing signal.

Helicopter integrated fire and flight control having coordinated area

During operation of a flight control system in a coupled aiming mode, wherein a fire control system (55) azimuth command and elevation command provide an aircraft attitude reference, a bank angle calculation function (1077) provides a bank angle signal to place the aircraft in a roll angle which results in a substantially coordinated turn. The bank angle signal is determined primarily as a function of an aiming line of sight heading rate for small azimuth commands, and is determined primarily as a function of aircraft heading rate for large azimuth commands. Additionally, the bank angle initially comprises a component as a function of aircraft lateral acceleration for driving aircraft lateral acceleration to zero, and after the aircraft assumes a roll attitude for turn coordination, the bank angle comprises a component as a function of aircraft side slip for driving aircraft side slip to zero. Automatic turn coordination is disabled if the pilot maneuvers the aircraft to avoid a coordinated turn, and is re-enabled if the pilot maneuvers the aircraft into a coordinated turn attitude. A rate feedback path (143) is provided during operation in the coupled aiming mode wherein aircraft yaw and pitch rate error signals are respectively replaced by the rate of change of the azimuth command and the elevation command. During operation in the coupled aiming mode, intended pilot commanded maneuvers maintain full authority at all times.

Helicopter integrated fire and flight control system having turn

A bias voltage, which can be added to force commands applied to a helicopter control stick actuator, to compensate for static null offset errors, is generated as the average of the summation or integral of actuator pressure, or pressure differential, sensed while the force is moved from a first position which is halfway aft through null to a second position which is halfway forward and back through null to the first position, the pressure readings which are averaged being taken only through the central portion of the motion, the motion being controlled to be extremely slow compared to normal permissible stick motion.

Helicopter force feel actuator automatic static null compensation

The foldable rotor blades (12) of a helicopter are automatically adjusted to pitch angles where they can be locked as a prerequisite to folding, by commands generated (98, 112) to cause trim actuators (39-41) to drive swash plate servos (17-19) to the correct positions, initially (98) in response to stored trim references (120) and eventually (112) in response to the difference (109) between stored swash plate servo positions (120) and current servo positions (20-22). A claimed embodiment uses values of servo positions (20-22), just before unlocking the blades upon re-spreading them, to store, in nonvolatile memory (138), deviations (131) from nominal positions stored in read only memory, and generates (159) trim references in a subsequent folding operation in response to integrated values (166) to reduce actual position errors (162) toward zero from desired positions indicated by the stored deviations (148).

Updated lock-positioning of foldable helicopter blades

The operation of an actuator (16) is monitored by comparing its position (21) with the position (31, 136) indicated by a model which integrates (45, 135) a limited amount of the difference between the position command (24) applied to the actuator and the achieved model position (31, 136), the limited amount being variable (63, 67, 124) from a nominal limit (61, 65, 124) in dependence upon limited functions (74, 90, 114, 116) of the difference (33, 109) between the actuator position and the model position, and additionally reduced (80, 94, 122) when pilot input overrides (50, 108) the position of the actuator.

Adaptive aircraft actuator fault detection

A system which provides feel-force to the control stick of an aircraft by means of hydraulic pressure is provided with non-nulling, proportional, direct feedback loop, and a limited integral feedback loop in the drive of the pressure control servo valve that commands the pressure-generating hydraulic force actuator. Static nulls are compensated in the integral path; integration is corrected when the static null and integral output exceed a limiting value. Embodiments include software and/or hardware portions.

Force feel actuator with limited proportional/integral error feedback

In a system which provides feel-force to the control stick of an aircraft by means of hydraulic pressure, a fault indicating system which responds to excessive differences between desired and actual force in the actuator, only of a polarity in the same direction as concurrent stick motion, to separate pilot induced pressure excesses from force-system faults, is provided with directional sensitivity in the fault-indicating output logic. Excessive pressure errors in either direction of stick travel institute the monitoring of changes in stick position. Changes in stick position of an excessive magnitude are recognized as fault only if they occur in the same direction as the direction of excessive pressure error. A simple analog embodiment utilizes threshold detectors and a track store device; a dedicated-digital embodiment utilizes comparators, registers and a subtractor; and a computer embodiment utilizes a software routine.

Force feel actuator fault detection with directional threshold

In a helicopter, a pilot-actuated lever controls, through linkage mechanisms, a servo valve to drive a hydraulic piston; the piston moves a swash plate which in turn controls movement of rotor blade pitch positioning mechanisms against the force of blade loading, caused by aerodynamic forces. Blade loading, heretofore monitored visually by the pilot on a cruise guide indicator instrument, is used herein to control a secondary input to the servo valve, thereby to alter the position linkage mechanism which causes the force of a spring attached thereto to impose a force on the collective pitch control for blade loadings in excess of one-third of maximum allowable blade loads, in a direction tending to drive the control to lower collective pitch (lower blade loading). This provides 'feel' to the pilot in proportion to blade loading when at critical magnitudes. A trim system is selectively actuatable to provide an input to the auxiliary valve which tends to maintain the collective pitch control in a selected position.

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Oxford, CT, United States of America

Donald W Fowler