Function block-based closed-loop adaptive machining for assembly interfaces of large-scale aircraft components

To guarantee the docking accuracy of large-scale components, their assembly interfaces usually need to be finished before the final assembly. However, there are some crucial problems affecting finishing efficiency and quality, e.g. use of hard-to-machine material at the assembly interface, manual interventions and process diversity in finish machining, difficulties in the alignment of the large component, as well as errors between the as-built and as-designed status of the large component. These problems significantly enhance the uncertainty in finish machining on a shop floor. To solve these problems, this paper proposes an approach of adaptive process planning and execution, i.e., IEC 61499 Function Block (FB) based Closed-Loop Adaptive Machining (CLAM). Thus, the adaptive alignment of the large component is achieved, which can guarantee the correct location between the assembly interface and the cutting tool. As well as the on-line CLAM of the assembly interface is also realized to improve the machining efficiency and quality. As a result, a FB based CLAM system for the assembly interfaces is established, which contains a CAD system, a FB enabled High-Level Controller (HLC), and several Low-Level Controllers (LLCs), as well as a mechanical system. The most notable is that the related FBs are designed to plan and execute the finishing process. Finally, the proposed method and system are validated by a large component from a real aviation industry, i.e., a vertical tail of a passenger aircraft. The experimental results indicate that the proposed method and system are feasible and effective to address the above-mentioned problems.