Research On Computer Aided Tolerance Analysis Oriented To Aircraft Manufacturing Coordination

Interchangeability coordination plays a great role in process planning of aircraft manufacturing,and it is the key and core technology of aircraft manufacturing. Meanwhile, tolerance analysis inaircraft manufacturing coordination is the important stage to achieve interchangeability coordination,therefore it directly affects the assembly yield, manufacturing quality and cost. Up to now, themethods of tolerance analysis used in aircraft manufacturing are mainly based on manual analysis andthe quality of analysis result is mostly depended on the experience of the technicians. All of thesecause many problems, such as low efficiency and long period. In addition, computer aided toleranceanalysis which has some problems is seldom applied. The development of tolerance analysis alreadycannot meet the demand of the aircraft manufacturing and is the bottleneck problem of high quality.Hence, according to the present situation and actual demand of the aeronautical manufacturingenterprise, and associating with the project of civil aircraft, the technology of computer aidedtolerance analysis oriented to aircraft manufacturing coordination is researched and the system isdeveloped. The main research in this thesis is outlined as follow:(1) The technology of computer aided aircraft manufacturing coordination route graph design isstudied. Based on the analysis of research literatures actuality, the definition of computer aidedaircraft manufacturing coordination route graph and its icon are summarized and given. Then, theObject-Oriented graphic drawing scheme is described in detail by UML, class diagram and activitydiagram are respectively used to describe organization structure and design process of coordinationroute graph. The information and relationship of coordination icons are stored efficiently by treestructure. Automatic layout algorithm in aircraft manufacturing coordination route graph is proposed,which can realize the graphic display of aircraft manufacturing coordination route. And the graph isused as data source for tolerance analysis.(2) An unified tolerance model which is oriented aircraft manufacturing coordination process isproposed. Through analyzing aircraft manufacturing coordination problems, different coordinationtolerance models are built by the classification of aircraft manufacturing coordination problems. Then,the each coordination process is described in a directed graph. Finally, by summing the above directedgraphs, the unified tolerance model for aircraft assembly coordination problem is built, which can beexpressed by directed graph and its adjacency matrix.(3) Coordination accuracy analysis of typical coordination problems is studied. First, a method to get function equations from the coordination process model is presented. Then, probability methodand extremum method which are used to calculate the accumulated error are introduced. The methodto analysis coordination accuracy is presented based on the analysis and summary of configurationand intersection coordination accuracy problems.(4) Based on the above theoretical studies, an aircraft manufacturing coordination orientedtolerance analysis system is developed. The application shows that the system can meet the demandsof coordination accuracy analysis and improve the efficiency of marking process planning of aircraftmanufacturing.