Double Redundancy Electrohydrostatic Actuator with Shared Accumulators
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Solution Overview
Problem
Existing double redundancy electro hydrostatic actuator systems for dual tandem hydraulic cylinders are not compact or lightweight, as they require extensive hydraulic circuits and heavy hydraulic pumps, limiting their efficiency and practicality, especially in applications like airplane wings.
Innovation Solution
A double redundancy electro hydrostatic actuator system is designed with two hydraulic pumps, fail-safe valves, accumulators, and switching valves, allowing for efficient fluid management and piston rod operation using two hydraulic circuits, reducing the need for heavy hydraulic pumps and enhancing system reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional hydraulic circuits are used for dual redundancy electro hydrostatic actuator system, then system reliability is improved, but system weight and size increase
Solution Approach 1:
The patent merges the functions of two separate hydraulic circuits into a shared accumulator system. Both hydraulic circuits (A system and B system) connect to common accumulators, allowing the accumulators to store hydraulic energy for both systems. This consolidation reduces the total number of components needed while maintaining the redundancy capability, thereby reducing system weight without compromising reliability.
Solution Approach 2:
The accumulators serve multiple functions: they store hydraulic energy for normal operation, provide backup pressure during circuit failures, and enable the fail-safe valve to switch between different operational states. This multi-functionality eliminates the need for separate backup systems for each hydraulic circuit, reducing overall system weight and complexity while maintaining dual redundancy.
2Reliability
If traditional hydraulic circuits are used for dual tandem hydraulic cylinder, then system reliability is improved, but system volume and complexity increase
Solution Approach 1:
The patent combines the hydraulic circuit architecture by having both A system and B system share common accumulators and use a unified fail-safe valve mechanism. This merging reduces the number of independent components and simplifies the overall system architecture while preserving the dual redundancy capability that ensures reliability.
Solution Approach 2:
The accumulators are pre-charged with hydraulic pressure and ready to provide backup power before any failure occurs. The fail-safe valve is pre-configured with spring mechanisms that automatically activate upon pressure loss. These preliminary preparations eliminate the need for complex real-time decision-making systems, simplifying control logic while ensuring reliable automatic switching upon failure.
3Power
If heavy hydraulic pumps are used to ensure sufficient hydraulic pressure, then hydraulic power is improved, but system weight increases
Solution Approach 1:
The accumulators are pre-charged with hydraulic pressure during normal operation when power is available. This stored hydraulic energy is then available immediately upon failure without requiring heavy-duty pumps to generate pressure on demand. The preliminary charging of accumulators eliminates the need for oversized pumps, reducing system weight while maintaining sufficient hydraulic power for emergency operation.
Solution Approach 2:
The patent uses hydraulic accumulators to store energy in liquid form, replacing the need for mechanical energy storage systems or oversized pumps. The hydraulic fluid itself serves as the energy storage medium, and the accumulators provide a compact, lightweight solution for storing sufficient hydraulic power to operate the actuator during emergency conditions.
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 compact and lightweight design while maintaining dual redundancy, ensuring reliable operation of the dual tandem hydraulic cylinder even when one hydraulic circuit fails, with reduced weight and increased efficiency.
Implementation Method 1
Each of the two accumulators accumulates fluid from a corresponding one of the two hydraulic pumps, and sends the fluid to a corresponding one of the two fail safe valves
Implementation Method 2
Switching of the fail safe valve 16 is performed among the three states by supplying the hydraulic fluid to the small and large pistons of the fail safe valve 16 such that the spool valve 27 is switched
Implementation Method 3
In the third state, the piston rod 20 performs a damping operation, since the flow of the hydraulic fluid is reduced even when external force is applied to the piston rod 20
Data Source
AI summary
A double redundancy electro hydrostatic actuator system includes two hydraulic pumps; two fail safe valves connected with the two hydraulic pumps, respectively; one dual tandem hydraulic cylinder connected with the two fail safe valves and having a piston rod, wherein the piston rod is moved by switching supply and discharge of the fluid; two switching valves connected with the two fail safe valves; two accumulators connected with the two switching valves and the two hydraulic pumps, respectively; and two chambers connected with the two switching valves, respectively. Each of the two accumulators accumulates the fluid from a corresponding one of the two hydraulic pumps, and sends the fluid to a corresponding one of the two fail safe valves. The two chambers receive the fluid from the two fail safe valves, respectively.