Sikorsky Aircraft Corporation

United Technologies Corporation

Bryan S Cotton

Christopher A Thornberg

Kevin L Bredenbeck

Kenneth C Arifian

Erez Eller

Matthew T Luszcz

Christopher L Winslow

Matthew Harrigan

Mark K Wilson

David M Walsh

Yuriy Gmirya

Don L Adams

Thomas L Tully, Jr

Leslie Schweizer

Jeffrey L Cevette

Sherman Corning, Iii

Yuriy Z Gmirya

Thomas J Tully

An aircraft is provided and includes an airframe, an extending tail, a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly, a translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe, at least one sensor and at least one inertial measurement unit (IMU) to sense current flight conditions of the aircraft, an interface to execute controls of a main rotor assembly in accordance with control commands and at least one flight control computer (FCC) to issue the control commands. The at least one FCC includes a central processing unit (CPU) and a memory having logic and executable instructions stored thereon, which, when executed, cause the CPU to issue the control commands based on the current flight conditions and a result of an execution of the logic for the current flight conditions.

Dual rotor, rotary wing aircraft

A pitch control system configured to vary a pitch angle of at least one of a plurality of propeller blades of a propeller system is provided including a switch movable between a neutral position and a plurality of non-neutral positions. Movement of the switch to a first non-neutral position generates a command to move the propeller blades in a first direction. Movement of the switch to a second non-neutral position generates a command to move the propeller blades in a second direction. Movement of the switch to a third non-neutral position generates a command to move the propeller blades to a zero thrust position.

Rotary wing aircraft pitch control system

Pitch control system

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly composed of a plurality of blades and a lower rotor assembly composed of a plurality of blades. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. A flight control system to control the upper rotor assembly and the lower rotor assembly, wherein the flight control system is configured to control lift offset of the upper rotor assembly and the lower rotor assembly.

Lift offset control of a rotary wing aircraft

Embodiments are directed to obtaining a first analog signal corresponding to a position error between a commanded gang output of a plurality of electro-mechanical actuators configured to be run in parallel with one another and a measured gang output of the plurality of electro-mechanical actuators, obtaining a second analog signal corresponding to an output torque, and processing, by a circuit, the first analog signal and the second analog signal to generate and output a discrete that indicates a status of the torque in terms of direction and magnitude.

Fly by wire servos with internal loop closure

An aircraft is provided and includes an airframe, first and second main rotors rotatably supported on the airframe to rotate about a rotational axis in opposite directions, first and second emitters disposed on an emitter blade of the second main rotor, each of the first and second emitters being configured to emit an emission toward a detector blade of the first main rotor, a detector disposed on the detector blade of the first main rotor, the detector being configured to detect the emissions of the first and second emitters and a flight computer which determines a clearance between the first and second main rotors in accordance with detections of the emissions by the detector.

Tip clearance measurement

A drive system for a high speed rotary-wing aircraft includes a combiner gearbox in meshing engagement with a main gearbox. The combiner gearbox is driven by one or more engines such that a main rotor system and a translational thrust system are driven thereby. The engine drives the combiner gearbox and thus the main gearbox through an overrunning clutch. The drive system permits the main rotor system RPM to be controlled by offloading power to the translational thrust system during a high speed flight profile.

Rotor drive and control system for a high speed rotary wing aircraft

A translational thrust system for a high speed rotary-wing aircraft includes a propeller system driven by a propeller gearbox, a hydraulic system, and a mechanical-hydraulic control system. The mechanical-hydraulic control system utilizes a hydraulic fluid which travels to and from a propeller dome via an oil transfer/position feedback tube which translates with a propeller pitch change piston. Translation of the oil transfer/position feedback tube and the propeller pitch change piston pitches the blades between high (coarse) and low (fine) pitch positions.

Translational thrust system for a rotary wing aircraft

An aircraft autopilot system provides a wind correction angle which is added to the desired course to provide commanded heading, the wind correction angle being generated as a proportional and integral function of ground track error. When the aircraft is off its desired course, it can be returned to the desired course by means of a course intercept angle, added to the desired course, to provide a corrected commanded course, the course intercept angle being a proportional function of the perpendicular error (the lateral distance of the aircraft from the original course) suitably limited to some angle within 90.degree. of the desired course. The course correction angle may be generated as a proportion of the perpendicular course error determined by the degree of importance of accuracy, and may be switched over to a course directly toward a waypoint in dependence upon the importance of efficiency. The course intercept angle may be a variable proportion of the perpendicular error as a function of the importance of accuracy, and the limits on the intercept angle determined by the relative importance of efficiency.

Aircraft course correction for wind and fuzzy logic course intercept

In a rotary wing aircraft, longitudinal groundspeed error and lateral groundspeed error are converted to earth coordinates, and the result scaled and integrated, and retransformed into aircraft coordinates for application to a pitch attitude control system and a roll attitude control system. The invention thus instantly transfers wind trim between the longitudinal and lateral channels, whenever a heading change is undertaken.

Earth-referenced wind adjustment for hovering aircraft

The airspeed limiting performance envelope of a helicopter is converted to a groundspeed envelope by factoring-in the wind speed and direction. A groundspeed command for an unmanned helicopter is provided as a function of the range to the helicopter's destination. The function may be calculated so as to provide a nominal groundspeed command equal to a nominal groundspeed command limit, or the function may be a fixed function to cause the aircraft to creep toward final approach. The cosine and sine of the desired relative flight direction of the aircraft, which is equal to the true bearing to the destination minus the true heading of the aircraft, are utilized to scale the groundspeed command into a longitudinal groundspeed command and a lateral groundspeed command. If one of the groundspeed commands is over a corresponding limit, the other groundspeed command is scaled back so that the vector addition of the two commands will cause flight in the desired direction. Exceedance of either a right or left groundspeed command, as well as saturation of the right or left cyclic pitch channel will cause the aircraft heading to be yawed into the direction of the limit exceedance or channel saturation.

Navigation of helicopter with limited polar groundspeed commands

A vertical performance limit compensator is provided for a rotary wing aircraft. The compensator modifies a vertical velocity command signal for the aircraft's autopilot. The vertical velocity command signal represents a desired vertical velocity for the aircraft, and results in an associated engine power demand. Existing engine power remaining beyond that required for level flight is excess engine power. An engine performance signal is provided as an indication of an engine power demand that exceeds the excess engine power. A compensated vertical velocity command signal having a magnitude lower than the vertical velocity command signal is provided in response to the vertical velocity command signal and the presence of the engine performance signal.

Vertical performance limit compensator

Apparatus and method for controlling an unmanned generally aerodynamically symmetric aircraft includes detecting the presence of misalignment between the horizontal component of the center of gravity vector and the horizontal component of the direction of flight vector and further includes rotating the aircraft to align the horizontal components of the vectors.

Cyclic minimizer through alignment of the center of gravity and

A frame of reference is selected, and control inputs provided by a vehicle operator are transformed to account for the orientation of a remotely operated vehicle with respect to the selected frame of reference such that the remotely operated vehicle responds to the control inputs with respect to the selected frame of reference. An earth frame of reference may be selected based on a fixed true heading, e.g., North, or based on the initial orientation of the vehicle operator. Alternatively, a vehicle frame of reference may be selected which provides a fixed frame of reference with respect to the vehicle and a variable frame of reference with respect to the vehicle operator. A vehicle operator frame of reference may also be selected based on the orientation of the vehicle operator with respect to earth, and control commands are transformed based on changes in both the operator orientation with respect to the earth reference and the remotely operated vehicle orientation with respect to the earth reference, which provides a fixed frame of reference with respect to the vehicle operator and a variable frame of reference with respect to the vehicle. The remotely operated vehicle heading transformation may be based on a selected forward, fixed or variable point on the vehicle related to a vehicle center of gravity, a forward part of the vehicle, the location of a sensor on the vehicle, or some other arbitrary reference location on the vehicle.

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Monroe, CT, United States of America

Bryan S Cotton