Method and device for determining a state of a rotorcraft rotor
AssigneeAirbus Helicopters
InventorJean-Paul Petillon
Life of this patent
Estimating the term…
Abstract
A device for determining a state of a rotor of a rotorcraft. The rotorcraft comprises a fuselage and a main rotor provided with a hub rotating about a mast of the rotor and with a plurality of blades whose second ends describe a trajectory defining a tip path plane. The device includes a sensor for measuring an angular velocity of a blade about a pitch axis. The device thus makes it possible to determine a state of the rotor, comprising, for example, estimates of a longitudinal cyclic pitch and of a lateral cyclic pitch of the blade with respect to the tip path plane.
Claims13
A method for determining a state of a rotor of a rotorcraft, the rotorcraft comprising a fuselage and at least one rotor provided with a mast, a hub, and a plurality of blades, each blade comprising a first end and a second end, the hub connected to the mast and rotating about an axis of the mast, each blade connected by the first end to the hub, each blade being able to rotate about at least one articulation axis of the blade, the second end of each blade defining, during a rotation of the hub about the axis of the mast, a trajectory close to a mean plane referred to as the tip path plane,
- wherein the method comprises:
- directly measuring the change over time of an angular velocity component of one blade about the articulation axis with respect to an inertial reference frame;
- and
- determining a state of the rotor by processing solely the angular velocity component, the state of the rotor comprising a longitudinal cyclic pitch and a lateral cyclic pitch of the blade with respect to the tip path plane determined by extracting an amplitude and a phase of a fundamental sinusoidal component of the angular velocity of the blade about the articulation axis, wherein the fundamental sinusoidal component has a frequency equal to that of rotation of the hub of the rotor about the axis of the mast;
- wherein the state of the rotor further comprises an elevation angle of the blade with respect to the tip path plane and longitudinal and lateral inclination angles of the tip path plane with respect to a plane of the hub perpendicular to the axis of the mast;
- wherein the method includes a step of performing an assisted or automatic take-off of the rotorcraft by slaving the tip path plane according to a predetermined inclination setpoint with respect to a horizontal plane;
- and
- wherein, during the step of performing an assisted or automatic take-off of the rotorcraft, a pilot of the rotorcraft acts solely on a lever for controlling the collective pitch of the blades of the rotor, the cyclic pitches of the blades of the rotor being controlled automatically in order to slave the longitudinal and lateral inclination angles of the tip path plane with respect to a horizontal plane, regardless of the slope of the ground and regardless of the wind acting on the rotorcraft.
A rotorcraft comprising:
- a fuselage and a rotor, the rotor provided with a mast, a hub, and a plurality of blades, each blade comprising a first end and a second end, the hub being connected to the mast and being rotatable about an axis of the mast, each blade being connected by a first end to the hub, each blade being able to rotate about an articulation axis of the blade, the second end of each blade describing, during a rotation of the hub about about the axis of the mast, a trajectory close to a mean plane referred to as the tip path plane;
- a device comprising a sensor and a calculator,
- the sensor configured to measure a change over time of an angular velocity component of a blade about the articulation axis with respect to an inertial reference frame, and
- the calculator configured to determine a state of the rotor, the state of the rotor comprising a longitudinal cyclic pitch and a lateral cyclic pitch of the blade with respect to the tip path plane determined by extracting an amplitude and a phase of a fundamental sinusoidal component of the angular velocity of the blade about the articulation axis, wherein the fundamental sinusoidal component has a frequency equal to that of rotation of the hub of the rotor about the axis of the mast;
- wherein the state of the rotor further comprises an elevation angle of the blade with respect to the tip path plane and longitudinal and lateral inclination angles of the tip path plane with respect to a plane of the hub perpendicular to the axis of the mast;
- and
- an autopilot configured to perform an assisted or automatic take-off of the rotorcraft by slaving the tip path plane according to a predetermined inclination setpoint with respect to a horizontal plane, wherein, during the assisted or automatic take-off of the rotorcraft being performed, a pilot of the rotorcraft acts solely on a lever for controlling the collective pitch of the blades of the rotor, the cyclic pitches of the blades of the rotor being controlled automatically in order to slave the longitudinal and lateral inclination angles of the tip path plane with respect to a horizontal plane, regardless of the slope of the ground and regardless of the wind acting on the rotorcraft.
Dependencies are inferred from the claim text.