The Key Technologies Of Intelligent Machining Based On Dynamic Machining Feature For Aerospace Structrual Parts

Aerospace structural parts have large dimension and large amount of material removal, which need long machining time. Considerbable complex thin-walled structures are comprised of aerospace structural parts with high machining accuracy requirement, which require sophisticated machining processes. There are many uncertain factors of manufacturing resources and workpiece stations during manufacturing process, which have imposed new challenges for the NC machining process planning efficiency and process quality control of complex parts. In order to address the issues mentioned above, the dissertation focuses on the key technologies of intelligent machining based on dynamic machining feature for aerospace structural parts. The research achievements include:(1) Dynamic machining feature concept is proposed and dynamic machining feature model is constructed. Not only interim machining state geometries of feature are defined, the interim machining state geometries of feature with machining process, inspection information, and monitoring information are also defined by dynamic machining feature. In order to address the issue of the association of dynamic machining feature information, the interim geometric state of each machining occasion is constructed, and the association of interim machining state geometry of feature with non-geometric information is constructed based on time series.(2) An adaptive process planning method based on dynamic machining feature is proposed. The machining process knowledge of aerospace structural parts is expressed based on dynamic machining features, and the framework including distributed adaptive off-line process planning and on-line process adjustment is realized. In order to address the uncertainty of manufacturing resource, manufacturing resource decision, cutting parameter optimization, and automatic tool path generation is realized based on dynamic machining features and Agent. In order to address the workpice deformation during machining process, real time monitoring, on-machine inspection, and tool path adjustment is realized based on Function Block and dynamic machining features.(3) An on-line adaptive tool path adjustment method based on dynamic machining feature is proposed. For the elastic deflection induced by cutting force, the differential beam of interim state of machining feature calculation model is studied, cutting force is collected by real time monitoring, and the real time calculation and compensation of the elastic deflection error induced by cutting force is realized. For the plastic deformation induced by random factors such as residual stress, the interim machining state is inspected online, the qualification criterion of the machining state of interim feature by considering dimensional tolerance, shape tolerance, and position tolerance is constructed, and the the drive geometry of interim feature is constructed for tool path adjustment, the adaptive control during NC machining process of thin-walled parts is realized.(4) A dynamic machining feature based intelligent machining system for aerospace structrual parts is developed, and it has been implemented and validated in the manufacturing of several complex structural parts from some domestic aircraft manufacturing enterprises.