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US 2019/0193835 A1Published application
Controlling blade pitch by a plurality of electric motors
AssigneeFLIR Unmanned Aerial Systems AS
InventorsPal H. Sandberg, Petter Muren, Trygve F. Marton, Ivar Johnsrud
Life of this patent
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Abstract
The present invention relates to a rotor assembly where associated electric motors are configured to rotate the rotor, control the collective pitch of the rotor/assembly, and/or control the cyclic pitch of the rotor/assembly, by varying the relative rotational angle between two or more of the associated electric motors.
Claims20
A thrust generating rotor assembly for a vehicle, the thrust generating rotor assembly comprising:
- a first rotor blade configured to rotate around a rotor shaft axis with a nominal first blade pitch angle and to pitch around a longitudinal rotor blade axis;
- first and second electric motor units configured to drive the thrust generating rotor assembly and characterized by a first relative rotational angle, the first and second electric motor units respectively connected to concentrically oriented first and a second rotor shafts able to rotate relative to each other around the rotor shaft axis, wherein the first rotor shaft runs through the center of the second rotor shaft;
- a pitch connection between the first and the second rotor shafts and the first rotor blade, configured to alter the first blade pitch angle in response to altering the first relative rotational angle of the motor units according to a predefined ratio between the first relative rotational angle and the first blade pitch angle depending on a mechanical structure of the pitch connection;
- and
- a motor controller configured to control the first relative rotational angle and thereby control the first blade pitch angle of the first rotor blade.
2 more elements
A method of operating a thrust generating rotor assembly for a vehicle, the method comprising:
- receiving first and second rotational positions of respective first and second electric motor units of the thrust generating rotor assembly, wherein the first and second electric motor units are respectively connected to concentrically oriented first and a second rotor shafts able to rotate relative to each other around a rotor shaft axis of the thrust generating rotor assembly;
- determining a first relative rotational angle between the first and second electric motor units based, at least in part, on the first and second rotational positions of the respective first and second electric motor units;
- and
- controlling the first and/or second electric motor units to adjust the first relative rotational angle and thereby adjust a first blade pitch angle of a first rotor blade of the thrust generating rotor assembly, wherein the thrust generating rotor assembly further comprises:
- a pitch connection between the first and the second rotor shafts and the first rotor blade, configured to alter the first blade pitch angle in response to altering the first relative rotational angle of the motor units according to a predefined ratio between the first relative rotational angle and the first blade pitch angle depending on a mechanical structure of the pitch connection.
2 more elements
Dependencies are inferred from the claim text.