Pneumatic Actuator System for Rotor Blade Vibration Control
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Solution Overview
Problem
Current rotor blade actuation methods, particularly those using piezoelectric materials, face significant weight penalties, reliability issues due to brittleness, and challenges in supplying high voltage for actuation, limiting their effectiveness in reducing helicopter vibrations and improving performance.
Innovation Solution
A pneumatic actuator system that utilizes centrifugally generated air pressure differentials within the rotor blade to actuate devices, eliminating the need for an auxiliary pressure source and providing a lightweight, low-power actuation mechanism by using pressure diaphragms and valves to control air flow between high and low pressure volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If piezoelectric actuators are used to actuate rotor blade control surfaces, then actuation force is provided, but weight penalty increases and reliability decreases due to brittleness
Solution Approach 1:
The patent employs pneumatic actuators that utilize compressed air stored in high-pressure volumes within the rotor blade to actuate control surfaces. This pneumatic approach replaces piezoelectric actuators, eliminating the weight penalty and brittleness issues while providing sufficient actuation force through pressure differential across a diaphragm.
Solution Approach 2:
The system uses the rotor blade's own rotation to generate the compressed air pressure differentials needed for actuation. The high-pressure volume is pressurized by centrifugal forces during rotation, making the system self-sufficient without external power sources or heavy mechanical actuators.
2Force
If piezoelectric stack actuators are used for larger scale applications, then larger force output is achieved, but displacement decreases and structural housing requirements increase weight
Solution Approach 1:
The patent uses pneumatic pressure to directly actuate control surfaces through a diaphragm mechanism, eliminating the need for heavy piezoelectric stack actuators and their associated structural housings. The compressed air provides both the force and displacement needed for effective control surface actuation.
Solution Approach 2:
The actuation system is divided into distributed high-pressure volumes and individual actuators along the rotor blade span, allowing each actuator to be lightweight while the collective system provides the necessary total force output for vibration control.
3Ease of operation
If high voltage is supplied to piezoelectric actuators on rotating blades, then actuation is achieved, but reliability issues arise from electrical connection challenges
Solution Approach 1:
The patent replaces electrical actuation with pneumatic actuation, using compressed air delivered through pneumatic conduits rather than electrical connections. This eliminates the reliability issues associated with high-voltage electrical connections on rotating blades while maintaining full actuation capability.
Solution Approach 2:
The system substitutes electrical fields with pneumatic pressure fields for actuation, replacing the need for electrical power transmission with a mechanical pneumatic system that is inherently more reliable in rotating applications.
4Object-affected harmful factors
If passive vibration absorbers are used, then vibration reduction is achieved, but weight penalty increases and off-design performance is poor
Solution Approach 1:
The pneumatic actuators are self-actuating, using the rotor blade's rotation to generate the compressed air pressure differentials needed for vibration control. This eliminates the need for heavy external power sources or complex mechanical vibration absorbers, achieving vibration reduction with minimal added weight.
Solution Approach 2:
The system dynamically adjusts actuation parameters by controlling the timing and magnitude of pneumatic pressure application to actuators, enabling effective vibration control across varying flight conditions and rotor speeds without requiring heavy passive absorbers.
5Adaptability or versatility
If multiple discrete piezoelectric flaps are mounted on rotor blades, then control flexibility increases, but system complexity and weight increase
Solution Approach 1:
The patent uses pneumatic actuators distributed along the rotor blade that can be independently controlled, providing the same control flexibility as multiple piezoelectric flaps but with simpler system architecture. Each pneumatic actuator is fed from the integrated high-pressure volume system, reducing overall complexity.
Solution Approach 2:
The high-pressure volume system serves multiple functions: it stores compressed air for actuation, provides structural integration within the blade, and enables multiple actuators to be supplied from a single pneumatic infrastructure, reducing the need for separate systems for each control element.
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 solution enables efficient on-blade actuation with reduced weight and increased reliability, effectively controlling rotor blade surfaces to enhance vibration reduction, aeromechanical stability, and noise reduction, while minimizing the structural and maintenance burdens associated with traditional actuation methods.
Implementation Method 1
During rotation of the rotor blade, the leading edge volume develops a relatively high pressure and the trailing edge volume develops a relatively low pressure when compared to the atmospheric pressure
Data Source
AI summary
A pneumatic actuator system to provide for actuation of a device on a rotor blade. A high pressure volume unit mounted on the rotor blade, including an air inlet to allow entrance of air into the high pressure volume. At least one actuator on the rotor blade to actuate a device on the rotor blade, where the at least one actuator is connected to the high pressure volume to receive air from the high pressure volume for actuation. An air release unit connected to the at least one actuator to allow release of air from the at least one actuator. An air control unit connected to the high pressure volume unit to control air flow into the at least one actuator and is connected to the air release unit to control release of air from the at least one actuator.