# US 11,440,650 B2 · Independent control for upper and lower rotor of a rotary wing aircraft

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- Number: US 11,440,650 B2
- Document ID: US11440650B2
- Status: Granted
- Kind: B2
- Application number: 15/504,525
- Filed: 2015-09-30
- Published: 2017-08-17
- Granted: 2022-09-13
- Earliest claimed: 2014-10-01
- Assignees: Sikorsky Aircraft Corporation
- Applicants: Sikorsky Aircraft Corporation
- Inventors: Erez Eller; Matthew A. White; David H. Hunter
- Web page: https://patentgrep.com/patent/US11440650B2

## CPC

- B64C 27/16: Drive of rotors by means, e.g. propellers, mounted on rotor blades
- B64C 1/0009: {Aerodynamic aspects}
- B64C 7/00: Structures or fairings not otherwise provided for
- B64C 13/04: actuated personally
- B64C 13/18: using automatic pilot
- B64C 13/50: using electrical energy
- B64C 13/503: {Fly-by-Wire}
- B64C 19/00: Aircraft control not otherwise provided for
- B64C 27/001: {Vibration damping devices}
- B64C 27/006: {Safety devices}
- B64C 27/008: {Rotors tracking or balancing devices}
- B64C 27/10: arranged coaxially
- B64C 27/12: Rotor drives
- B64C 27/14: Direct drive between power plant and rotor hub
- B64C 27/32: Rotors
- B64C 27/322: {Blade travel limiting devices, e.g. droop stops}
- B64C 27/33: having flexing arms
- B64C 27/467: Aerodynamic features
- B64C 27/473: Constructional features
- B64C 27/48: Root attachment to rotor head
- B64C 27/51: Damping of blade movements
- B64C 27/52: Tilting of rotor bodily relative to fuselage (of see-saw type construction B64C27/43)
- B64C 27/54: Mechanisms for controlling blade adjustment or movement relative to rotor head, e.g. lag-lead movement
- B64C 27/57: automatic or condition responsive, e.g. responsive to rotor speed, torque or thrust
- B64C 27/78: in association with pitch adjustment of blades of anti-torque rotor
- B64C 27/80: for differential adjustment of blade pitch between two or more lifting rotors
- B64C 27/82: characterised by the provision of an auxiliary rotor or fluid-jet device for counter-balancing lifting rotor torque or changing direction of rotorcraft
- B64D 35/06: the propellers or rotors being counter-rotating
- B64D 39/00: Refuelling during flight
- B64D 39/06: Connecting hose to aircraft; Disconnecting hose therefrom
- B64D 45/02: Lightning protectors; Static dischargers
- F16F 15/02: Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems ({F16F15/005 takes precedence } ; layered products B32B; suppression of vibration in ships B63; {relieving load on bearings, using magnetic means F16C39/06})
- F16H 37/02: comprising essentially only toothed or friction gearings
- G05D 1/0077: {using redundant signals or controls}
- G05D 1/0202: {specially adapted to aircraft}
- G05D 1/0816: {to ensure stability}
- G05D 1/0858: {specially adapted for vertical take-off of aircraft}
- G05D 1/49: Control of attitude, i.e. control of roll, pitch or yaw
- G05D 1/689: Pointing payloads towards fixed or moving targets (positioning towed, pushed or suspended implements G05D1/672)
- B64C 27/08: with two or more rotors
- B64C 2027/004: {using actuators, e.g. active systems}
- B64C 2027/8209: {Electrically driven tail rotors}
- B64C 2027/8227: {comprising more than one rotor}
- B64C 2027/8236: {including pusher propellers}
- B64C 2027/8263: {comprising in addition rudders, tails, fins, or the like}
- B64C 2027/8272: {comprising fins, or movable rudders}
- B64C 2027/8281: {comprising horizontal tail planes}
- B64U 10/10: Rotorcrafts
- F02C 9/28: Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed (F02C9/30 - F02C9/38, F02C9/44 take precedence)
- F05D 2220/329: in helicopters
- F05D 2270/021: to prevent overspeed
- F16D 13/52: Clutches with multiple lamellae {; Clutches in which three or more axially moveable members are fixed alternately to the shafts to be coupled and are pressed from one side towards an axially-located member (F16D13/385 takes precedence)}
- F16D 13/72: Features relating to cooling
- F16D 13/74: Features relating to lubrication
- G05D 1/0204: {to counteract a sudden perturbation, e.g. cross-wind, gust}
- G05D 1/08: Control of attitude, i.e. control of roll, pitch, or yaw
- G05D 2105/22: of humans
- G05D 2105/35: for combat
- G05D 2109/25: Rotorcrafts
- Y02T 50/10: Drag reduction
- B64C: AEROPLANES; HELICOPTERS
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16H: GEARING
- G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- B64U: UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

An aircraft is provide including an airframe, an extending tail, and 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 flight control computer configured to independently control the upper rotor assembly and the lower rotor assembly through a fly-by-wire control system. A plurality of sensors to detect sensor data of at least one environmental condition and at least one aircraft state data, wherein the sensors provide the sensor data to the flight control computer.

## Claims

### Claim 1

An aircraft comprising:
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 flight control computer is configured to independently control the upper rotor assembly and the lower rotor assembly through a fly-by-wire control system; and
a plurality of sensors to detect sensor data of at least one environmental condition and at least one aircraft state data;
wherein the sensors provide the sensor data to the flight control computer which imparts control commands to establish control limits for at least one of a collective control, a lateral cyclic control, and a longitudinal cyclic control for each of the upper rotor assembly and the lower rotor assembly based on the at least one environmental condition and the at least one aircraft state data included in the sensor data, the control limits being defined as at least one of a ganged limit and a differential limit, the ganged limit being defined as a limit on an average of a pitch value of the upper rotor assembly control and a pitch value of the lower rotor assembly control, and the differential limit being defined as a limit on a difference between the pitch value of the upper rotor assembly control and the pitch value of the lower rotor assembly control divided in half.

### Claim 2 (depends on 1)

The aircraft of claim 1 wherein:
in response to at least one control input, the flight control computer is configured to utilize algorithms based on the sensor data and the control input to produce a separate control command output for the upper rotor assembly and a separate control command output for the lower rotor assembly.

### Claim 3 (depends on 1)

The aircraft of claim 1 wherein:
the flight control computer is configured to separately limit the control command output for the upper rotor assembly and the control command output for the lower rotor assembly by an individual control mechanism limit.

### Claim 4 (depends on 3)

The aircraft of claim 3 wherein:
the flight control computer is configured to prioritize the control command limits such as ganged, differential, independent rotors, or a combination thereof.

### Claim 5 (depends on 4)

The aircraft of claim 4 wherein:
the flight control computer is configured to impose a control range for the control command output on the upper rotor assembly and impose a different control range for the control command output on the lower rotor assembly.

### Claim 6 (depends on 1)

The aircraft as in claim 1 wherein:
the upper rotor assembly and the lower rotor assembly are controlled separately by individual swashplates.

### Claim 7 (depends on 1)

The aircraft as in claim 1 wherein:
the upper rotor assembly and the lower rotor assembly are controlled separately by individual blade control mechanisms.

### Claim 8 (depends on 1)

The aircraft of claim 1, wherein:
at least one upper rotor blade of the upper rotor assembly includes a first antenna and at least one lower rotor blade of the lower rotor assembly includes a second antenna, and
a blade proximity monitor detects a distance between the first antenna and the second antenna.

### Claim 9 (depends on 8)

The aircraft of claim 8, wherein:
an oscillator sends an excitation signal to the first antenna, and wherein the second antenna receives a signal emitted by the first antenna.

### Claim 10

A method of operating an aircraft, comprising:
receiving, with a plurality of sensors, sensor data of at least one environmental condition and at least one aircraft state data;
receiving, with at least one flight control computer, at least one control input and the sensor data;
determining, with the flight control computer, separate control command outputs for the upper rotor assembly and the lower rotor assembly based on the control input and the sensor data; and
commanding, with the flight control computer, a separate control command output on the upper rotor assembly and a separate control command output on the lower rotor assembly with the separate control commands establishing control limits for at least one of a collective control, a lateral cyclic control and a longitudinal cyclic control for each of the upper rotor assembly and the lower rotor assembly based on the at least one environmental condition and the at least one aircraft state data included in the sensor data, the control limits being as at least one of a ganged limit and a differential limit, the ganged limit being defined as a limit on an average of a pitch value of the upper rotor assembly control and a pitch value of the lower rotor assembly control, and the differential limit being defined as a limit on a difference between the pitch value of the upper rotor assembly control and the pitch value of the lower rotor assembly control divided in half.

### Claim 11 (depends on 10)

The method according to claim 10 wherein:
the flight control computer separately limits the control command output for the upper rotor assembly and the control command output for the lower rotor assembly by an individual control mechanism limit.

### Claim 12 (depends on 10)

The method according to claim 10 wherein:
the flight control computer imposes a control range for the control command output on the upper rotor assembly and imposes a different control range for the control command output on the lower rotor assembly.

### Claim 13 (depends on 10)

The method as in claim 10 wherein:
the upper rotor assembly and the lower rotor assembly are controlled separately by individual swashplates.

### Claim 14 (depends on 10)

The method as in claim 10 wherein:
the upper rotor assembly and the lower rotor assembly are controlled separately by individual blade control mechanisms.

### Claim 15 (depends on 10)

The method of claim 10, wherein:
at least one upper rotor blade of the upper rotor assembly includes a first antenna and at least one lower rotor blade of the lower rotor assembly includes a second antenna; and
a blade proximity monitor detects a distance between the first antenna and the second antenna.

### Claim 16 (depends on 15)

The method of claim 15, wherein:
an oscillator sends an excitation signal to the first antenna, and wherein the second antenna receives a signal emitted by the first antenna.