Angle measurement technology of hatch door based on multi-line LiDAR

The opening angle of the aircraft hatch door is crucial for ensuring weapon delivery safety and serves as a necessary test subject in flight testing. Currently, the angle measurement of the hatch door can only determine its open or closed state without providing quantitative measurements. The traditional method of measuring the control mechanism's angle in flight tests involves installing a contact line displacement sensor at the linkage mechanism, which is not suitable for small locations. This paper presents a designed multi-line LiDAR system to address these issues. By scanning the hatch door with multi-line LiDAR, three-dimensional point cloud data is obtained and subjected to feature extraction and normalization processing under different open and closed states, enabling accurate acquisition of the hatch door's opening angle. This method eliminates the need for installing contact sensors on the linkage mechanism, thereby ensuring test safety. Additionally, by utilizing an RANSAC algorithm to fit point cloud data, model accuracy is enhanced leading to improved test precision. In this paper, the reflector plate is used to replace the hatch door for laboratory verification test. The test results show that the multi-line LiDAR system has high measurement accuracy and can be put into practical application.