Development And Positional Accuracy Analysis Of Flexible Track Automatic Drilling System

To meet the requirement of long life, high assembly quality and efficiency of modern aircraft, precision drilling by automatic equipment is one important method. Automatic drilling technology and equipment development have reached a high level aboard. However, we are still drilling holes by hand in traditional way at home, which cannot meet the requirement of high quality of holes and high efficiency of assembly. Based on the background, a flexible automatic drilling system which is applied to joining area between aircraft fuselages is developed, and some key techniques are studied, including hardware and software design, coordinate system modeling, hole position and normal vector correcting.Firstly, the research and development of automatic drilling technology in aircraft digital assembly are summarized, especially for the flexible track automatic drilling technology. Then based on the background of engineering application, a flexible automatic drilling system is established. The construction and function of each part are introduced in detail, and the capability indicator of the system is proposed. After definitude the design requirement of the flexible track, a control system is built based on a real-time fieldbus named SynqNet, and the configuration of hardware control network is presented. Based on the hardware, the software of flexible track automatic drilling control system is developed, and the function modules of the software are introduced in detail.To achieve precision automatic drilling, flexible track needs to construct coordinate systems and accomplish the transition relationships between product coordinate system and axis parameters. The coordinate system modeling process is presented. The forward and reverse algorithm of kinematical equation of this drilling system is illustrated. Furthermore, the principle and process of coordinate system rebuilding and the normal vector correction technique are proposed.The position precision an the repetition precision of each axis are measured. The coordinate system transition algorithm accuracy is also measured, and an optimize scheme is explored. At last, a drilling experiment is implemented by the flexible track system. The experimental results show that the system can immensely improve the efficiency and quality of aircraft panel assembly. The countersink deep control is better than0.02mm, the normal accuracy is better than±0.5°, and the efficiency of drilling can achieve3-5holes per minute.