Span-wise Actuator with Cross-axis Flexure Pivot
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Solution Overview
Problem
The design of powerful, lightweight actuator systems for active aerodynamic surfaces in rotary-wing and tilt-rotor aircraft poses challenges due to added weight and complexity, which existing systems struggle to address effectively.
Innovation Solution
The use of linear actuators with a span-wise orientation and cross-axis flexure pivot elements, which create a negative stiffness spring effect to counteract centrifugal forces, reducing actuator power requirements and mass, while allowing for more powerful motors and improved mass distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If actuator systems are added to operate active elements on blades or wings, then performance improvements and vibration reduction are achieved, but weight and complexity increase
Solution Approach 1:
The patent employs centrifugal force generated by rotor rotation to counteract the weight and power requirements of the actuator system. The span-wise oriented linear actuators utilize the rotating blade's centrifugal environment to reduce the power needed to operate aerodynamic surfaces, effectively using the system's own operational dynamics to offset the added weight penalty.
Solution Approach 2:
The invention replaces traditional mechanical actuation systems with linear motor actuators that operate in the span-wise direction, utilizing electromagnetic fields rather than purely mechanical linkages. This substitution reduces mechanical complexity and weight while maintaining actuation capability.
2Ease of operation
If traditional actuator systems are used to drive aerodynamic surfaces, then actuation function is achieved, but power requirements and system complexity increase
Solution Approach 1:
The actuator system is segmented into multiple span-wise oriented linear actuators distributed along the blade span. Each actuator independently controls a portion of the aerodynamic surface, allowing distributed control that reduces individual actuator complexity and power requirements while maintaining overall system functionality.
Solution Approach 2:
The patent transitions from traditional chord-wise actuation to span-wise actuation, changing the dimensional orientation of the actuator system. This dimensional change allows utilization of centrifugal forces in the rotating reference frame, simplifying the actuation mechanism and reducing system complexity.
3Power
If powerful actuators are designed to overcome centrifugal forces, then actuation capability is improved, but weight increases
Solution Approach 1:
The system uses centrifugal force from rotor rotation to counterbalance the weight and power demands of the actuators. By orienting actuators span-wise, the design harnesses the rotating environment's centrifugal effects to reduce the net power requirement, allowing powerful actuation capability without proportional weight increase.
Solution Approach 2:
The actuator system is designed to operate dynamically within the rotating blade environment, adapting to centrifugal forces rather than resisting them statically. This dynamic approach allows the actuators to leverage rotational motion to achieve powerful actuation with reduced weight compared to static designs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the adverse effects of centrifugal forces, enables more powerful and efficient actuation, and enhances mass distribution, leading to improved performance and reduced weight in aircraft actuator systems.
Implementation Method 1
cross-axis flexure pivot elements, which create a negative stiffness spring effect to counteract centrifugal forces
Implementation Method 2
counteract centrifugal forces
Data Source
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AI summary
A method and apparatus is provided, including an actuator system that may be connected to a wing frame for controlling an active element. The actuator system may include sliding elements movable along an axis parallel to the span-wise axis of the wing. The sliding elements may be connected to fixed elements and a crank element, the crank element generally comprising a beam element and a cross-axis flexure pivot element. The beam element may be offset from the pivot element so that the crank element is rotatable about the pivot element with a negative stiffness under an external force that tends to pull the sliding elements away from the fixed elements.