Multistep Workpiece Localization with Automated Symmetry Identification for Aerospace Carbon Fiber Reinforced Plastic Components

Carbon fiber reinforced plastic (CFRP) fuselage and wing panels are being increasingly adopted for aircraft to reduce the aircraft weight, resulting in a reduction in fuel consumption and pollutant emission. CFRP panels are commonly manufactured on flexible manufacturing systems to maximize profit. However, the flexibility of the systems is gained at the cost of manufacturing accuracy, and a workpiece localization process, for finding six rigid transformation parameters, should be introduced in the manufacturing process for compensating for the inevitable workpiece location error. For symmetric workpieces, such as cylindrical fuselage panels, some of the transformation parameters are free, and therefore, multiple localization solutions exist, which are geometrically identical but result in different machining conditions. This paper proposes a multistep workpiece localization method with automated symmetry identification for determining the symmetry of symmetric CFRP panels and finding an optimal solution from numerous solutions. For a symmetric workpiece, the symmetry information, comprising the symmetry type and change-of-basis matrix, is extracted using slippage analysis with an infinitesimal transformation assumption. The extracted information is then used to separately construct nonsymmetric and symmetric transformation matrices for initial localization and final adjustment steps. In the initial localization, a nonsymmetric transformation is determined to minimize the workpiece’s profile error, and in the final adjustment, a symmetric transformation is identified to minimize the compensation (i.e., six rigid transformation parameters) without changing the minimum profile error. The proposed method was verified by conducting four case studies, and it showed high practical applicability.