Helicopter Blade Actuation System Using Giant-Magnetostrictive Pump
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Solution Overview
Problem
Current actuation systems for helicopters are large, heavy, and lack precision in controlling blade flaps, leading to increased vibrations and noise, with existing solutions either having small output force or limited range of movement.
Innovation Solution
A compact actuation system utilizing a giant-magnetostrictive pump and piezoelectric valves, integrated within the blade, to control hydraulic pressure and drive flaps with high precision and larger stroke, eliminating the need for a swash plate and reducing noise and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a hydraulic source is arranged on the airframe to transmit hydraulic pressure to rotating blades, then the actuation system can provide strong output force, but the structure becomes complex and the system size increases
Solution Approach 1:
The hydraulic system is segmented into distributed units within each blade rather than a centralized system on the airframe. Each blade contains its own hydraulic source and control mechanisms, eliminating complex transmission mechanisms and reducing overall system complexity while maintaining actuation force capability.
Solution Approach 2:
A hydraulic fluid serves as an intermediary to transmit force from compact hydraulic sources within each blade to the flap actuation points. This allows strong output force to be achieved without direct mechanical connection from the airframe, simplifying the overall structure.
2Volume of moving object
If a bimorph type piezoactuator is used to drive flaps, then the structure can be compact, but the stroke (movable range) becomes small
Solution Approach 1:
The patent replaces traditional mechanical leverage mechanisms with a hydraulic actuation system. Instead of using mechanical amplification that increases complexity, hydraulic pressure directly drives the flap through a piston-cylinder mechanism, achieving large stroke without increasing actuator size.
Solution Approach 2:
A hydraulic cylinder with piston is used to convert hydraulic pressure into linear motion with large stroke. The hydraulic fluid transmits force efficiently, enabling the flap to achieve a large movable range while the hydraulic source remains compact within the blade.
3Length of moving object
If a laminate type piezoactuator with leverage is used to enlarge movable range, then the stroke increases, but the driving force becomes small and precision decreases due to mechanical fluctuation
Solution Approach 1:
The patent eliminates mechanical leverage mechanisms that cause precision loss due to mechanical fluctuation. Instead, hydraulic pressure directly controls the piston position, providing precise and stable control of the flap angle without the errors introduced by mechanical linkages.
Solution Approach 2:
The hydraulic system provides smooth, fluctuation-free force transmission to the piston. Hydraulic fluid is incompressible and transmits pressure uniformly, ensuring precise control of the movable member position without the mechanical play and friction associated with leverage mechanisms.
4Force
If a complex transmission mechanism is used to transmit hydraulic pressure from airframe to rotating blade, then the actuation can be achieved, but the structure becomes complex and size increases
Solution Approach 1:
The hydraulic system is divided into independent units within each blade rather than a centralized system requiring complex transmission. Each blade self-contained hydraulic source and actuation mechanism, eliminating the need for long hydraulic lines and complex transmission components across the rotor assembly.
Solution Approach 2:
The hydraulic source and actuation mechanisms are nested within the blade structure itself. The hydraulic cylinder, piston, and control valves are integrated into the blade's internal volume, utilizing the blade's own structure as the mounting framework and eliminating external transmission components.
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 achieves a smaller size, lighter weight, and higher precision in controlling blade orientation, significantly reducing noise and vibrations while providing a strong output force and larger range of movement.
Implementation Method 1
a giant-magnetostrictive element 33 connected to the piston 32 at another end. The giant-magnetostrictive element 33 changes a capacity of the pump chamber 35 by driving the piston 32 with respect to the cylinder 31 because of the deformation.
Implementation Method 2
a piezoelectric element 48 arranged in parallel to the movable member 43. The piezoelectric element 48 deforms based on applied voltage to drive the movable member 43.
Implementation Method 3
check valves 15 and 16. The check valve 15 opens between the flow path 24 and the flow path 22, and closes between the flow path 24 and the flow path 22. The check valve 16 opens between the flow path 24 and the flow path 23, and closes between the flow path 24 and the flow path 23.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
In an aspect of the present invention, an actuation system includes: a pump assembly (11) configured to form a pump chamber; an actuator (6) having first and second chambers and a movable member (42) and configured to convert pressures applied to the first and second chambers into a movement of the movable member; and a valve section (12;13). A controller (7) controls the valve section to open a first flow path between the pump chamber and the first chamber and close a second flow path between the pump chamber with the second chamber, during a discharge period during which the pump chamber is pressurized, in a first mode; to close the first flow path and open the second flow path during an intake period during which the pump chamber is depressurized, in the first mode; to close the first flow path and open the second flow path during the discharge period in a second mode; and to open the first flow path and close the second flow path during the intake period in the second mode.