A posture adjustment optimization method of the laser inspection device for large complex surface parts

Abstract

The blank of large complex surface parts such as aircraft skin parts is formed by roll–bending process, which always introduces a big shape deviation between actual blanks and the desired ones. The cutting tool path for the blank machining planned based on the nominal digital model of the part may scrap the part due to the shape deviation. In order to address this issue, laser inspection method is used to inspect the blank before machining to obtain the actual shape of the blank which can be used as a reference for cutting tool path generation in addition to the nominal digital model of the part. While the laser inspection device posture adjustment is an important factor for inspection precision, it should be intensively focused. The difficulty of the laser inspection device posture adjustment optimization is that it can only be performed based on the nominal digital model of the part, while the real inspection object is the actual blank whose real shape is unknown, which may lead to the inspection precision disqualification. In order to address the above difficulty, the actual blank profile is first constructed with a few of laser inspection points obtained by rough inspecting. An inspection path planning method is proposed based on the actual blank profile. A genetic algorithm is used to optimize the pendulum angles of the laser inspection device based on the inspection path and the actual blank profile, and the optimized postures of the actual blank can be calculated based on the pendulum angles. The proposed method of this article is verified by the inspection of an aircraft skin part, and the experiment results show that this method can ensure the final inspection precision.