Abstract: A device for automatically detecting a through-hole rate of a honeycomb sandwich composite-based acoustic liner, including a customized tooling, a data acquisition system, a motion mechanism and a data processing system. The data acquisition system is configured to acquire a surface three-dimensional (3D) point cloud data of an acoustic liner using a two-dimensional (2D) laser profile sensor in a manner of parallel movement shooting, and connected with a graphics workstation. The motion mechanism includes an industrial robot, and the 2D laser profile sensor is fixed at an end of the industrial robot. The motion mechanism is configured to support the data acquisition system to perform translational scanning. The data processing system includes the graphics workstation, and plays a role of path planning and data storage. A method for automatically detecting a through-hole rate of a honeycomb sandwich composite-based acoustic liner is also provided.

Abstract: A method for positioning a communication device includes: receiving measurement information between a node to be positioned and a set of reference nodes of at least one type, the measurement information including an initial pseudorange and initial orientation angle measurement information between the node to be positioned and a reference node, and the set of reference nodes including at least one reference node; and substituting the measurement information into a preset parametric formula to obtain positioning information of the node to be positioned, the parametric formula being used for indicating a possibility that the positioning information is a value of a preset variable, and the positioning information including position information, clock deviation information and orientation angle information of the node to be positioned.

Abstract: A feature-guided scanning trajectory optimization method for a 3D measurement robot, including: building a 3D digital model of an aircraft surface; obtaining a size of the 3D digital model; extracting features to be measured; classifying the features to be measured; calculating a geometric parameter of each type of features to be measured; generating an initial scanning trajectory of each type of features to be measured; building a constraint model of the 3D measurement robot; optimizing the initial scanning trajectory into a local optimal scanning trajectory; and planning a global optimal scanning trajectory of each type of features to be measured on the aircraft surface by using a modified ant colony optimization algorithm.

Abstract: A feature-guided scanning trajectory optimization method for a 3D measurement robot, including: building a 3D digital model of an aircraft surface; obtaining a size of the 3D digital model; extracting features to be measured; classifying the features to be measured; calculating a geometric parameter of each type of features to be measured; generating an initial scanning trajectory of each type of features to be measured; building a constraint model of the 3D measurement robot; optimizing the initial scanning trajectory into a local optimal scanning trajectory; and planning a global optimal scanning trajectory of each type of features to be measured on the aircraft surface by using a modified ant colony optimization algorithm.

Abstract: The present disclosure provides a point cloud denoising method based on multi-level attention perception, including the following steps: constructing a data set of point cloud denoising; constructing a point cloud denoising neural network, including a patch feature encoder, a global level perception module, a global level attention module, and a multi-offset decoder module, and training a network model by using the data set of point cloud denoising; for input point cloud, separately obtaining a neighborhood patch of a point of each original data point, and inputting coordinates of each data point in the neighborhood patch of a point to a trained denoising neural network to obtain a location offset of each original point; and separately adjusting, based on the obtained location offset, a location corresponding to each original data point in the input point cloud, to complete point cloud denoising.

Abstract: A fairing skin repair method based on measured wing data includes fairing skin registration. Data set P1 through denoising and filtering wing point cloud data is reorganized to obtain a key point set P. A histogram feature descriptor in a normal direction of any key point in set P and a skin point cloud data Q is calculated. Euclidean distance between feature descriptors of two points is calculated through K-nearest neighbor algorithm, and points with high similarity are added into a set M. A clustering is performed on set M using a Hough voting algorithm to obtain a local point cloud set P? in set P. The method includes fairing skin repair. The boundary line of the point frame is projected onto Q, and a distance between a projection line on the point cloud and the boundary line is calculated to obtain an amount of skin to be repaired.

Abstract: A method for automatic glue-spraying of stringers and inspection of glue-spraying quality based on measured data. Three-dimensional (3D) point cloud data of a stringer-skin assembly is collected by 3D laser scanner, and then processed by denoising and sampling. Feature points of an intersection line of a site to be glued of the stringer-skin assembly are extracted by K-means clustering method based on Gaussian mapping, and a minimum spanning tree is constructed based on a set of the extracted feature points. A connected region is established to obtain an initial feature intersection line of the string-skin assembly, which is optimized by random sample consensus algorithm to remove redundant small branch structures to obtain the actual glue-spraying trajectory. The quality of the glue sprayed on the stringer-skin assembly is inspected by line laser to determine positions of the defects, which are then subjected to secondary glue-spraying.

Abstract: A device for automatically detecting a through-hole rate of a honeycomb sandwich composite-based acoustic liner, including a customized tooling, a data acquisition system, a motion mechanism and a data processing system. The data acquisition system is configured to acquire a surface three-dimensional (3D) point cloud data of an acoustic liner using a two-dimensional (2D) laser profile sensor in a manner of parallel movement shooting, and connected with a graphics workstation. The motion mechanism includes an industrial robot, and the 2D laser profile sensor is fixed at an end of the industrial robot. The motion mechanism is configured to support the data acquisition system to perform translational scanning. The data processing system includes the graphics workstation, and plays a role of path planning and data storage. A method for automatically detecting a through-hole rate of a honeycomb sandwich composite-based acoustic liner is also provided.

Abstract: A method for positioning a communication device includes: receiving measurement information between a node to be positioned and a set of reference nodes of at least one type, the measurement information including an initial pseudorange and initial orientation angle measurement information between the node to be positioned and a reference node, and the set of reference nodes including at least one reference node; and substituting the measurement information into a preset parametric formula to obtain positioning information of the node to be positioned, the parametric formula being used for indicating a possibility that the positioning information is a value of a preset variable, and the positioning information including position information, clock deviation information and orientation angle information of the node to be positioned.

Abstract: A fairing skin repair method based on measured wing data includes fairing skin registration. Data set P1 through denoising and filtering wing point cloud data is reorganized to obtain a key point set P. A histogram feature descriptor in a normal direction of any key point in set P and a skin point cloud data Q is calculated. Euclidean distance between feature descriptors of two points is calculated through K-nearest neighbor algorithm, and points with high similarity are added into a set M. A clustering is performed on set M using a Hough voting algorithm to obtain a local point cloud set P? in set P. The method includes fairing skin repair. The boundary line of the point frame is projected onto Q, and a distance between a projection line on the point cloud and the boundary line is calculated to obtain an amount of skin to be repaired.

Abstract: A method for automatic glue-spraying of stringers and inspection of glue-spraying quality based on measured data. Three-dimensional (3D) point cloud data of a stringer-skin assembly is collected by 3D laser scanner, and then processed by denoising and sampling. Feature points of an intersection line of a site to be glued of the stringer-skin assembly are extracted by K-means clustering method based on Gaussian mapping, and a minimum spanning tree is constructed based on a set of the extracted feature points. A connected region is established to obtain an initial feature intersection line of the string-skin assembly, which is optimized by random sample consensus algorithm to remove redundant small branch structures to obtain the actual glue-spraying trajectory. The quality of the glue sprayed on the stringer-skin assembly is inspected by line laser to determine positions of the defects, which are then subjected to secondary glue-spraying.

Abstract: Disclosed a multi-station scanning global point cloud registration method based on graph optimization, including acquiring multi-station original three-dimensional point cloud data; based on initial registration of targets, completing initial registration of point cloud data at adjacent stations by virtue of the target at each angle of view; calculating a point cloud overlap area at adjacent angles of view, and calculating areas of overlap regions of adjacent point cloud by a gridded sampling method; constructing a fine registration graph structure, and constructing a fine registration graph by taking point cloud data of each station as a node of the graph and taking an overlap area of the point cloud data of adjacent stations as a side of adjacent nodes of the graph structure; and based on loop closure fine registration based on graph optimization, gradually completing point cloud fine registration of the whole aircraft according to a specific closure sequence.