Convertible Aircraft Rotor Pitch Control With Split Actuators
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Solution Overview
Problem
Conventional pitch control systems for convertible aircraft using common actuators suffer from reduced sensitivity, increased weight, maintenance costs, and off-axis loads, which affect the precision and reliability of blade pitch control.
Innovation Solution
A pitch control system with independent slider and swashplate actuators, allowing for precise collective and cyclic pitch control of rotor blades by translating a slider along the rotor axis and rotating a swashplate assembly about a tilt axis, using separate actuators to achieve collective and cyclic pitch changes independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If common actuators are used for both collective and cyclic pitch control, then device complexity is reduced, but manufacturing precision and control sensitivity deteriorate
Solution Approach 1:
The pitch control system is segmented into two independent actuator systems: a first actuator for collective pitch control and a second actuator for cyclic pitch control. This segmentation allows each actuator to be optimized for its specific function, maintaining high precision while managing overall system complexity through functional separation rather than using a single multi-functional actuator.
2Device complexity
If common actuators are used for pitch control, then device complexity is reduced, but reliability deteriorates
Solution Approach 1:
By dividing the pitch control function into two separate actuators, the system improves reliability through functional independence. Each actuator can be optimized and maintained independently, reducing the risk that a single point of failure will compromise both collective and cyclic pitch control functions.
3Device complexity
If common actuators are used for pitch control, then device complexity is reduced, but weight increases
Solution Approach 1:
The segmented actuator architecture allows for more efficient weight distribution. Each actuator can be sized and configured for its specific control function, avoiding the need for an oversized single actuator that would be required to handle both collective and cyclic control demands simultaneously.
4Device complexity
If common actuators are used for pitch control, then device complexity is reduced, but maintenance costs increase
Solution Approach 1:
Independent actuators enable modular maintenance and repair operations. If one actuator requires maintenance, the other can continue to operate, allowing for phased maintenance schedules and reducing operational downtime. This modular approach simplifies troubleshooting and repair procedures compared to a integrated common actuator system.
5Device complexity
If common actuators are used for pitch control, then device complexity is reduced, but off-axis loads increase friction and sticking
Solution Approach 1:
By separating collective and cyclic pitch control into independent actuators, each actuator operates with optimized force vectors that minimize off-axis loading. The first actuator applies force primarily along the collective pitch axis, while the second actuator handles cyclic pitch rotations, reducing cross-axis friction and sticking problems that would occur in a common actuator system.
Data Source
AI summary
An aircraft includes a body having a fuselage and a wing assembly, a main shaft supported for rotation with respect to the body about a rotor axis, and a blade assembly coupled to the main shaft for corotation therewith. The blade assembly includes a rotor hub and a plurality of blades circumferentially spaced about the rotor hub. Each blade is coupled to the rotor hub for rotation about a respective blade axis. The aircraft includes a pitch control system coupled to the blade assembly to rotate each blade about the respective blade axis. The pitch control system includes a slider, a swashplate, a first actuator coupled to the slider, and a second actuator operable to rotate the swashplate assembly with respect to the slider.