A Rapid Reverse Modeling Method Of Tire Pattern Based Point Cloud

With the advent of computer-aided design and intelligent manufacturing,3D geometric models play an important role in the field of product manufacturing,analysis and redesign.And reverse engineering is a series of processes in the transformation from real products to 3D model.Due to tire's double-curvature structure and the complex and subtle grooves,it bring a lot of difficulties to the reverse modeling process.Aiming to rapidly,efficiently and accurately generate a 3D tire geometric model,this paper proposed a new reverse modeling method for common passenger radial tire pattern and developed a dedicated reverse modeling system.The main research contents are as follows:(1)In order to facilitate the storage and operation of point cloud data measured by tread scanning equipment,it is transformed into a 2D point cloud mapping array with depth information.Then,based on the face-based and edge-based segmentation method,the point cloud mapping array is divided to single-feature tread data matrix and informative groove data matrix.(2)Parameterize the tire tread pattern,and extract and reconstruct the top surface and bottom surface,which paly crucial roles in pattern groove modeling,based on the segmented data matrix.(3)Referring to the area growth method in pattern recognition,we construct the data structures of row and column chain codes to respectively implement effective extraction and management of the longitudinal and transversal grooves.For the intersected grooves,the method of intersection marking is adopted to divide the intersected patterns into various branches and judge whether the patterns are continuous through the width and trend.The extracted groove boundary information needs to be clustered and similar patterns superimposed to reduce possible defective border.(4)Calculate the feature points of pattern boundary and fit these discrete points by least square B-spline curve.Finally,a reverse modeling system was developed to implement the semantic feature modeling of grooves and to automate the overall reverse modeling steps based on CATIA / CAA,.(5)In order to verify the efficiency and accuracy of the modeling system,the article finally gives the test results of the reverse system and carries out the accuracy verification.