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.

飞机越来越多地采用碳纤维增强塑料（CFRP）机身和机翼板，以减轻飞机的重量，从而降低燃油消耗和污染物排放。CFRP面板通常在柔性制造系统上制造，以最大程度地提高利润。然而，系统的灵活性是以制造精度为代价的，并且为了找到不可避免的工件位置误差，在制造过程中应该引入用于找到六个刚性变换参数的工件定位过程。对于对称工件，例如圆柱形机身面板，一些变换参数是自由的，因此存在多个定位解，这些解在几何上是相同的，但是会导致不同的加工条件。本文提出了一种具有自动对称性识别的多步骤工件定位方法，用于确定对称CFRP面板的对称性并从众多解决方案中寻找最佳解决方案。对于对称工件，使用带有无限小变换假设的滑移分析来提取包括对称类型和基变矩阵的对称信息。然后，将提取的信息用于为初始定位和最终调整步骤分别构造非对称和对称变换矩阵。在初始定位中，确定非对称变换以最小化工件的轮廓误差，在最终调整中，确定对称变换以最小化补偿（即，六个刚性变换参数），而不会更改最小轮廓误差。进行了四个案例研究，验证了该方法的实用性。