Rotorcraft control system with stepped mixing linkage
AssigneeBell Helicopter Textron Inc.
InventorsCarlos A. Fenny, Duane Hicks
Life of this patent
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Abstract
A control system for a rotorcraft is disclosed. The control system includes a stepped mixing linkage, such that a selected amount of right-left lateral cyclic output is generated for certain amounts of forward-aft cyclic input. The stepped mixing linkage includes two supporting links and a floating link pivotally coupled between the two supporting links. The ratio of the lengths of the two supporting links to the length of the floating link is small, thereby generating a selected lateral sinusoidal output, a selected rotation of the sinusoidal output, and a selected ramped output in response to each forward-aft pilot input command.
Claims16
A control system for a rotorcraft comprising:
- a cyclic for receiving pilot input commands;
- a torque tube pivotally coupled to the cyclic;
- a forward-aft output link pivotally coupled to the torque tube for transmitting forward-aft pilot input commands to a main rotor;
- a stepped mixing linkage pivotally coupled to the torque tube;
- a ground link pivotally coupled between the stepped mixing linkage and a grounded structure;
- a lateral output link pivotally coupled to the stepped mixing linkage;
- and
- a left-right output link pivotally coupled to the lateral output link for transmitting left-right pilot input commands to the main rotor;
- wherein the stepped mixing linkage, the ground link, and the lateral output link are configured to generate a selected lateral sinusoidal output, a selected rotation of the sinusoidal output, and a selected ramped output in response to each forward-aft cyclic input command.
A rotorcraft comprising:
- a fuselage;
- a drive means carried by the fuselage;
- a main rotor coupled to the drive means;
- and
- a control system comprising:
- a cyclic for receiving pilot input commands;
- a torque tube pivotally coupled to the cyclic;
- a forward-aft output link pivotally coupled to the torque tube for transmitting forward-aft pilot input commands to a main rotor;
- a stepped mixing linkage pivotally coupled to the torque tube;
- a ground link pivotally coupled between the stepped mixing linkage and a grounded structure;
- a lateral output link pivotally coupled to the stepped mixing linkage;
- and
- a left-right output link pivotally coupled to the lateral output link for transmitting left-right pilot input commands to the main rotor;
- wherein the stepped mixing linkage, the ground link, and the lateral output link are configured to generate a selected lateral sinusoidal output, a selected rotation of the sinusoidal output, and a selected ramped output in response to each forward-aft pilot input command.
A stepped mixing linkage for use on an existing rotorcraft having a control system including a cyclic for receiving pilot input commands, a torque tube pivotally coupled to the cyclic, a forward-aft output link pivotally coupled to the torque tube for transmitting forward-aft pilot input commands to a main rotor, and a left-right output link for transmitting left-right input commands to the main rotor, the stepped mixing linkage comprising:
- two supporting links adapted for pivotal coupling to the torque tube;
- a floating link pivotally coupled between the two supporting links, the floating link having a central reference point;
- a lateral output link operatively associated with the floating link for transmitting left-right input commands through the left-right output link to the main rotor;
- and
- a ground link pivotally coupled between one of the supporting links, the ground link being adapted for pivotal coupling to a grounded structure on the existing rotorcraft;
- wherein the ratio of the lengths of the two supporting links to the length of the floating link is small, thereby generating a selected lateral sinusoidal output, a selected rotation of the sinusoidal output, and a selected ramped output in response to each forward-aft pilot input command.
A method of eliminating the cross-coupling effect in a rotorcraft comprising the steps of:
- providing a cyclic for receiving pilot input commands and transmitting the pilot input commands to a main rotor;
- pivotally coupling a torque tube to the cyclic;
- pivotally coupling a forward-aft output link to the torque tube;
- pivotally coupling a stepped mixing linkage to the torque tube;
- providing a stepped mixing linkage having two supporting links, a floating link pivotally coupled between the two supporting links, and a central reference point on the floating link;
- pivotally coupling the stepped mixing linkage to the torque tube;
- pivotally coupling a ground link between one of the supporting links and a grounded structure;
- pivotally coupling a lateral output link to the floating link at the reference point;
- and
- pivotally coupling a left-right output link pivotally the lateral output link through a bellcrank;
- and
- generating a selected lateral sinusoidal output, a selected rotation of the sinusoidal output, and a selected ramped output with the stepped mixing linkage, the ground link, and the lateral output link in response to each forward-aft pilot input command.
Dependencies are inferred from the claim text.