Rotor Blade Actuation System with Flexible Drive Tapes
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Solution Overview
Problem
Conventional actuation systems for rotor blades face issues such as increased drag, high friction, uneven motion, wear, and potential single-point failures, which affect controllability and aerodynamic performance.
Innovation Solution
A lightweight, compact, and wear-resistant actuation system using linear actuators with inboard and outboard frames, heat pipes for efficient heat dissipation, and flexible drive tapes, along with a flap mechanism that reacts centrifugal forces and allows for redundant actuation to prevent mechanical jamming and backlash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a bell crank and push/pull rod are used to actuate the trailing edge flap, then the flap can be controlled, but the bell crank penetrates the rotor blade profile and increases drag
Solution Approach 1:
The invention extracts the bell crank mechanism from the rotor blade profile by relocating it to the hub or a non-aerodynamic area. The push/pull rod connects the flap to the relocated actuator, allowing flap control without penetrating the blade's aerodynamic surface, thus eliminating the drag penalty while maintaining controllability.
Solution Approach 2:
The patent introduces a flexible coupling or intermediate mechanism that transmits actuation force from the relocated actuator to the flap without requiring direct penetration through the blade profile. This intermediary element allows force transmission while preserving the aerodynamic integrity of the blade surface.
2Strength
If conventional rod end elements are used in the actuation system, then mechanical connection is achieved, but high coulomb friction and uneven stick-slip motion occur
Solution Approach 1:
The invention replaces conventional rod end elements with a flexible coupling mechanism that eliminates rigid mechanical joints. This substitution removes the source of high coulomb friction and stick-slip motion, providing smooth continuous motion transmission while maintaining the necessary mechanical connection between actuator and flap.
Solution Approach 2:
The patent employs flexible couplings or thin film elements to transmit actuation forces. These flexible elements eliminate the rigid joint interfaces that cause friction and stick-slip behavior, while still providing adequate mechanical connection and force transmission for flap actuation.
3Duration of action of stationary object
If mechanical actuation components are used over time, then actuation function is maintained, but wear produces backlash and reduces controllability
Solution Approach 1:
The invention replaces wear-prone mechanical components with a flexible coupling system that has no sliding interfaces or ball screws. This eliminates the wear mechanisms that lead to backlash, maintaining precise controllability throughout the extended service life of the actuator while preserving the actuation function.
4Device complexity
If a single ball screw actuator is used, then compact actuation is achieved, but mechanical jamming creates a single point of failure
Solution Approach 1:
The invention segments the actuation function into multiple independent actuators or redundant drive mechanisms. Instead of relying on a single ball screw, the system uses multiple actuators that can independently actuate the flap, eliminating the single point of failure while maintaining compact overall system design through distributed actuation points.
Solution Approach 2:
The patent incorporates redundant actuation mechanisms that provide backup capability. If one actuator jams or fails, the redundant actuator(s) can compensate and maintain flap controllability. This beforehand cushioning against failure maintains system reliability without significantly increasing overall device complexity.
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
The system provides improved aerodynamic performance, reduced vibration, and enhanced controllability with high bandwidth and displacement capabilities, while being resistant to fatigue and single-point failures, maintaining aerodynamic profile integrity.
Implementation Method 1
heat pipes for efficient heat dissipation
Data Source
AI summary
In accordance with one embodiment of the present application, an actuation system is configured for actuation of an airfoil member with a flap mechanism. The actuation system can include an upper drive tape and a lower drive tape, each partially wrapped around a first bearing and second bearing. An inboard frame can be actuated by at least one linear actuator. Similarly, an outboard frame can be actuated by at least one linear actuator. The inboard frame is coupled to the upper drive tape, while the outboard frame is coupled to the lower drive tape. An actuation of the inboard frame and outboard frame in a reciprocal manner acts move a flap input lever reciprocally upward and downward. A flap mechanism is configured to convert the movement of the flap input lever into rotational movements of the airfoil member.