SPAC: Sparse sensor placement-based adaptive control for high precision fuselage assembly

Optimal shape control is important in fuselage assembly processes. To achieve high precision assembly, shape adjustment is necessary for fuselages with initial shape deviations. The state-of-the-art methods accomplish this goal by using actuators whose forces are derived from a model based on the mechanical properties of the designed fuselage. This has a significant limitation: they do not consider the model mismatch due to mechanical property changes induced by the shape deviation of an individual incoming fuselage. The model mismatch will result in control performance deterioration. To improve the performance, the shape control model needs to be updated based on the online feedback information from the fuselage shape adjustment. However, due to the large size of the fuselage surface, highly accurate inline measurements are expensive or even infeasible to obtain in practice. To resolve those issues, this article proposes a Sparse sensor Placement-based Adaptive Control methodology. In this method, the model is updated based on the sparse sensor measurement of the response signal. The reconstruction performance under a minor model mismatch is quantified theoretically. Its performance has been evaluated based on real data of a half-to-half fuselage assembly process, and the proposed method improves the control performance with acceptable sensing effort.