Linear Actuator Emergency Locking for Rotor Test Bench Failures
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Solution Overview
Problem
Linear actuating devices in applications like aircraft rotor test benches are prone to failures, which can cause malfunctions leading to severe damage, and existing technologies do not adequately address safety and control during such failures.
Innovation Solution
A linear actuating device with an emergency system that transitions from a nominal operating mode to an emergency mode upon failure, immobilizing the main rod in a predetermined refuge position using a secondary actuator and hydraulic blocker, and a tracking system to ensure precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear actuating device is used in a rotor test bench, then the rotor pitch can be controlled during normal operation, but the device is vulnerable to failures that can cause severe damage to the test bench and system
Solution Approach 1:
The emergency system is pre-configured with the secondary actuator and blocker positioned to automatically engage when failure occurs. The secondary actuator is pre-loaded with hydraulic fluid under pressure, ready to immediately drive the main rod to the refuge position without requiring complex real-time decision algorithms or multiple sensor arrays.
Solution Approach 2:
The emergency function is extracted as a separate, dedicated subsystem with its own actuator and control mechanism, independent from the main actuator's control system. This separation simplifies the overall system architecture by isolating safety-critical functions from the primary control loop, reducing the complexity of integrated control software and interconnections.
2Ease of operation
If the main rod is allowed to move freely during nominal operation, then the actuator can perform its function, but during failure the rod can move uncontrollably causing damage
Solution Approach 1:
The system dynamically transitions between two states: during nominal operation, the deformable clamping ring is expanded to allow free movement of the main rod for full operational range; upon failure detection, the ring contracts to lock the rod in place. This dynamic state change is achieved through simple hydraulic pressure reversal rather than complex mechanical linkages or programmable logic.
Solution Approach 2:
The deformable clamping ring acts as an intermediary element between the main rod and the secondary actuator. During normal operation, it permits rod movement while providing structural support. During emergency mode, it transforms into a locking mechanism that transmits the secondary actuator's force to immobilize the rod, eliminating the need for direct mechanical coupling or complex switching mechanisms.
3Reliability
If an emergency system is added to prevent uncontrolled movement, then safety is improved, but the device complexity increases
Solution Approach 1:
The secondary actuator serves multiple functions: it can drive the main rod to the refuge position during emergency mode, and potentially assist or backup the main actuator during nominal operation. The deformable clamping ring serves dual purposes as both a structural support element during normal operation and a locking mechanism during emergency mode, reducing the need for separate dedicated components.
Solution Approach 2:
The emergency system utilizes hydraulic fluid already present in the actuator system, leveraging the existing hydraulic infrastructure. The deformable clamping ring is expanded or contracted by redirecting hydraulic pressure, eliminating the need for separate pneumatic cylinders, motors, or complex mechanical actuation mechanisms for the emergency function.
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
Enhances safety by preventing free movement of the main rod during failures, maintaining the actuator in a safe position, and reducing the risk of damage to the test bench and system, while being adaptable to various rotor models.
Implementation Method 1
a deformable clamping ring configured: in the nominal operating mode, to enable frictionless sliding of the main rod with respect to the clamping ring; and in the emergency operating mode, to exert a pressing force on the main rod and secure together the main rod and the secondary rod in translation
Data Source
AI summary
A linear actuating device comprising a main actuator provided with a main body and with a main rod able to move with at least one degree of freedom in translation with respect to the main body. According to the disclosure, the linear actuating device comprises an emergency system configured, in a nominal operating mode of the linear actuating device, to allow the main rod to move with respect to the main body and, in an emergency operating mode of the linear actuating device, to return and then maintain the main rod in a predetermined refuge position.