Adaptive Nosewheel Damping via Magnetorheological Fluid
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Solution Overview
Problem
Nosewheel landing gear oscillations, known as shimmying, can lead to increased resonance and potential damage or loss of aircraft control due to unbalanced loadings, surface conditions, and vibrations, which existing damping arrangements fail to address effectively.
Innovation Solution
A controllable damping arrangement using a magneto-rheological fluid and solenoid to vary the damping load applied to the drive tube, sensed by an accelerometer and controlled to match the amplitude of shimmying oscillations, allowing for adaptive damping independent of the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant damping load is applied to the drive tube, then shimmying oscillations are damped, but the motor size increases and energy consumption rises
Solution Approach 1:
The damping load is made variable through a controllable damping device that adjusts the damping coefficient based on detected shimmy conditions. The damping device transitions from a static constant damping system to a dynamic adaptive system that modifies damping characteristics in real-time, allowing reduced damping when shimmy is absent and increased damping when shimmy occurs, thereby reducing the required motor size while maintaining effectiveness.
Solution Approach 2:
The damping coefficient parameter is changed dynamically based on operational conditions. A sensor detects shimmy oscillations and triggers a control mechanism that adjusts the damping parameter of the damping device, transforming it from a fixed parameter system to a variable parameter system that optimizes performance and reduces power requirements.
2Reliability
If a constant damping load is applied to the drive tube, then shimmying oscillations are damped, but energy consumption increases
Solution Approach 1:
The damping device operates periodically rather than continuously, activating only when shimmy oscillations are detected by the sensor. This periodic operation pattern allows the system to consume energy only when necessary for damping, rather than maintaining constant energy consumption, thereby reducing overall energy usage while maintaining damping effectiveness when needed.
Solution Approach 2:
The damping parameter is dynamically adjusted based on detected shimmy conditions, changing from a constant high damping state to a variable state that reduces damping (and energy consumption) when shimmy is absent, and increases damping when shimmy occurs, optimizing energy efficiency.
3Device complexity
If a simple damping device is used, then device complexity is reduced, but adaptability to varying shimmy conditions decreases
Solution Approach 1:
The complex mechanical control system for adjusting damping is replaced with a sensor-based detection and control mechanism. Instead of complex mechanical linkages and manual adjustment systems, the invention uses sensors to detect shimmy conditions and electronically controls the damping device, simplifying the overall structure while enhancing adaptability to varying conditions.
Solution Approach 2:
The damping system becomes self-regulating through sensor feedback, automatically detecting shimmy oscillations and adjusting its own damping output without external intervention. This self-service capability allows a relatively simple damping device structure to achieve high adaptability, as the system autonomously responds to varying operational 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
This solution effectively dampens shimmying motions by varying the damping load, preventing resonance and reducing the size of the motor required for steering, thus enhancing safety and reducing the risk of damage.
Implementation Method 1
The damping means conveniently comprises a magneto-rheological fluid located between the damping member and the damper housing, and a solenoid operable to control the magnetic field to which the magneto-rheological fluid is exposed.
Data Source
Figure 1
Figure 2
AI summary
A damping arrangement comprises a drive member (14) arranged to be driven for angular movement relative to a housing (20) by a motor (24), and a damping device (26) independent of the motor (24) and operable to damp oscillating motion of the drive member (14) relative to the housing (20).