Dual-Filter Transfer Alignment for Aircraft Wing Deformation
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Solution Overview
Problem
Current methods for measuring aircraft wing deformation using inertial navigation systems are limited by the assumption of rigid bodies, leading to unsatisfactory accuracy due to neglect of flexural deformation, and require high-precision IMUs that are impractical for installation on all loads, especially on aircraft wings.
Innovation Solution
A transfer alignment method based on dual filters under dynamic deformation, which models and analyzes error angles and angular speeds caused by coupling between fuselage movement and wing deformation, dividing the alignment process into two parts: one estimating flexural deformation and coupling angles using an attitude matching method, and the other estimating dynamic lever arm errors using a 'speed + angular speed' matching method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-precision IMU is installed on each load to improve measurement accuracy, then measurement precision improves, but weight and device complexity increase
Solution Approach 1:
The system divides the measurement function into two parts: a high-precision main IMU on the fuselage and low-precision subsidiary IMUs on the wings. The main IMU provides reference data, while subsidiary IMUs collect local deformation data. Through transfer alignment and data fusion, the system achieves accurate deformation measurement without requiring high-precision IMUs at all locations, thus reducing overall weight.
Solution Approach 2:
The main inertial navigation system acts as an intermediary between the fuselage and wing subsystems. It provides reference attitude and position data that are transferred to the subsidiary systems through transfer alignment. This intermediary role allows low-precision subsidiary IMUs to achieve accurate local measurements by referencing the high-precision main system, avoiding the need to install heavy high-precision IMUs on each wing.
2Device complexity
If the wings are treated as rigid bodies to simplify the model, then device complexity reduces, but measurement precision deteriorates due to neglect of flexural deformation
Solution Approach 1:
The system transitions from a static rigid body model to a dynamic flexible body model. It introduces time-varying parameters including flexural deformation angles, angular velocities, and accelerations to describe wing deformation. The transfer alignment model incorporates these dynamic parameters through differential equations, allowing the system to accurately track and compensate for flexible deformation during flight maneuvers.
Solution Approach 2:
The system changes the parameters used to describe wing behavior from fixed rigid body parameters to time-varying flexible body parameters. It introduces deformation angles, angular velocities, and accelerations as state variables that evolve over time. These parameter changes enable the model to capture the dynamic nature of wing flexure while maintaining mathematical tractability through differential equations.
3Measurement precision
If a comprehensive transfer alignment model including flexural deformation is used to improve accuracy, then measurement precision improves, but computational complexity increases
Solution Approach 1:
The comprehensive transfer alignment model is segmented into modular components: rigid body transformation matrices, flexural deformation angle calculations, angular velocity derivations, and acceleration terms. Each module handles a specific aspect of the transformation, making the overall computation more manageable. This modular segmentation allows for efficient implementation while maintaining high accuracy.
4Loss of time
If traditional transfer alignment methods are used to reduce alignment time, then alignment speed improves, but measurement precision deteriorates due to neglect of coupling errors
Solution Approach 1:
The system performs preliminary calculations of flexural deformation angles and their derivatives before executing the main transfer alignment computation. By pre-computing these deformation parameters and storing them for use in the alignment equations, the system avoids redundant calculations during the alignment process, thereby reducing overall alignment time while maintaining accuracy.
Data Source
AI summary
A dual-filter-based transfer alignment method under dynamic deformation. A dynamic deformation angle generated under dynamic deformation and a coupling angle between dynamic deformation and body motion will reduce the accuracy of transfer alignment; and a transfer alignment filter is divided into two parts, the first part estimates a bending deformation angle and the coupling angle, and uses an attitude matching method, and the second part estimates a dynamic lever arm, and uses a “speed plus angular speed” matching method.