The Research Of 3D Scanning Method Based On Dynamic Path Planning

In recent years,3D scanning technology has become the main method of non-contact measurement and has been widely applied in reverse modeling,cultural relic restoration,geographical mapping and other aspects in the engineering.During scanning the large components and complex surfaces,the project which using hand-held 3D scanning equipment to obtain the 3D data has become the main choice.However,some of the more dangerous work scenes do not allow operators to measure on-site which has become an important factor restricting the development of 3D scanning.The combination of 3D scanning technology and the robot makes automatic scanning of the object surface possible,at the same time,its advantages such as high security and repeatability satisfy the need of automatic manufacturing.The 3D scanning method based on dynamic path planning provides a feasible solution for “Robot Plus 3D Scanning” system.The 3D scanning method which has been proposed mainly designs a solution route include of 3D preliminary scanning,modeling by human-machine cooperate,dynamic path planning of second time scanning and scanning scheme implementation.The surface profile and appearance of the object have been obtained and analyzed through this scanning scheme,and the scanning position as well as the scanning path have been generated automatically aiming at the area of 3D data missing,which can improve the scan efficiency and quality effectively.The 3D scanning system has built using the industrial robot as a motion platform,and the way of 3D data acquisition and processing based on this system has been elaborated.The influence factors of scanning such as the lighting conditions,the surface color have been analyzed and verified through the experiment.The scanning speed and scanning effective rate which evaluate for scanning quality were proposed.Through the inspiration of the processing program of CNC machining,the scanning path of row scanning method has been designed.By comparing three kinds of path selection scheme of the preliminary scanning,the row scanning method has been selected to acquire the morphology and boundaries of the surface to be scanned,which has provide the data basis to the second time scanning.Judging the influence of the scanning quality due to the change of the scanning speed and scanning interval of the row scanning method,and optimizing the parameter combinations of impact factors through the orthogonal experiment.During the process of dynamic path planning of the second time scanning,the minimum enclosing ball which is a mathematics concept has been introduced for the first time into the 3D scanning path planning method.By using this concept to divide the area of 3D data missing reasonably,the sampling point to be scanned has been estimated as well as the scanning path has been planned automatically in the spherical domain.The determination method and criterion of the minimum enclosing ball based on the 3D scanning method have been elaborated as well as its arithmetic has been designed,and the operation efficiency of the minimum enclosing ball has been optimized.As the theoretical basis of the planning of scanning position and path,the constraint condition of 3D scanning has been proposed and the concept of visibility cone has been introduced.Using the theory of regional coverage,the number and positon of sample points,vision points and scanning directions have been designed and calculated as well as the scanning path has been generated and implemented.The feasibility of the 3D scanning method based on dynamic path planning has been verified in the actual surface measurement experiments as well as the scanning quality has been evaluated.The advantages and development direction of this 3D scanning method have been illustrated and the application of the 3D scanning method based on dynamic path planning in the engineering has been elaborated.