# A Dynamic Pose-Testing Technique of Landing Gear Combined Stereo Vision and CAD Digital Model

## TL;DR

This paper introduces a new method using stereo vision and CAD models to accurately measure the dynamic movement of aircraft landing gear during tests.

## Contribution

A novel visual measurement method combining stereo vision and CAD digital models for dynamic pose testing of landing gear is proposed.

## Key findings

- The method achieves an angle error RMSE of less than 0.1° and trajectory error RMSE under 0.3 mm.
- It provides greater environmental adaptability and reduces issues like occlusion during testing.
- The approach allows retrieval of pose information for any point on the landing gear, including its centroid.

## Abstract

The landing gear is one of the key components of an aircraft, enduring significant forces during takeoff and landing, and is influenced by various uncertain factors related to its structure. Therefore, conducting strength tests on the landing gear structure to study its ultimate load capacity is of great significance for structural design and analysis. This paper proposes a visual measurement method for dynamic pose of landing gear that combines stereo vision and CAD digital model. The method first establishes a measurement reference in CAD digital model and then uses close-range photogrammetry and binocular stereo vision technology to unify the coordinate system of the physical landing gear model with the measurement coordinate system of CAD model. Finally, during the motion of the landing gear, CAD model and the physical model can be synchronized by tracking a small number of key points, thus obtaining the complete motion state of the landing gear during the test. The experimental results demonstrate that the RMSE of the angle error is less than 0.1°, and the RMSE of the trajectory error is under 0.3 mm. This level of accuracy meets the requirements for pose measurement during the landing gear retraction and extension test. Compared to existing methods, this approach offers greater environmental adaptability, effectively reducing the impact of unfavorable factors such as occlusion during testing. It allows for the retrieval of pose information for any point on the landing gear, including its centroid.