Development of an Assembled Effective Independence Method for Optimal Sensor Placement in On-Orbit Assembly Structures

The optimization of sensor placement is essential for structural health monitoring in aerospace applications, driven by the need for both lightweight design and accurate measurement. Conventional optimal sensor placement (OSP) methods have achieved encouraging outcomes in optimizing for a specific fixed structure configuration. The growth in the scale of astronautic structures has led to a corresponding increase in the use of on-orbit assembly techniques for the construction of large-scale aerospace structures. However, the configuration and dynamic parameters of large-scale aerospace structures are subject to alteration during the on-orbit assembly stages. The sensor layout optimized for a specific structure configuration may not be suitable for other configurations during the on-orbit assembly stages. To address this issue, a new assembled effective independence (AEFI) method is proposed, taking into account the variations of dynamic parameters that occur as a result of the on-orbit assembly. In the proposed method, the AEFI coefficient is developed by a weighted summation of the effective independence coefficient for all configurations during the on-orbit assembly stages. Furthermore, the weighting factor is defined based on the number of target modes at each assembly stage. The OSP for on-orbit assembly structures can be obtained by using the backward sequential algorithm. The proposed method is validated on an assembled beam structure and compared with the traditional EFI method through three evaluation criteria. Finally, the AEFI method is applied to a simplified model of the Tiangong space station considering six assembly stages. Results based on different evaluation criteria demonstrate that the proposed AEFI method significantly improved the performance of sensor layouts for the structure during the assembly stages.