Multidisciplinary Multi-objective Optimization Design Method of Star Sensor Bracket

In order to meet the stringent requirements of high resolution optical satellite for lightweight and pointing accuracy of star sensors bracket, a multidisciplinary and multi-objective topology optimization method based on mechanics and thermodynamics is proposed, a cylindrical support with high specific stiffness and high pointing accuracy is designed. Firstly, the mathematical model of multi-objective topology optimization with minimum static compliance and maximum dynamic stiffness is established, and the optimization parameters are determined. Secondly, considering the structure and thermal stability, multidisciplinary and multi-objective collaborative optimization is carried out to obtain the optimal structure. Then, the thermal stability and dynamics of the optimized support are analyzed by the finite element method, the least square method is used to fit the thermal deformation data, and the pointing accuracy of the star sensor is calculated. Finally, the thermal vacuum and vibration response characteristic tests are carried out and verified. Results indicates that the natural frequency of the star sensor component is 425.6 Hz, the lightweight rate of structure is over 45%, the pointing accuracy is 2.71″, and cylindrical support has higher thermal stability and pointing accuracy, which meet the satellite′s requirements for high performance index. The test verifies the feasibility of optimization method, and provides an effective method for the structure design of high-precision devices.

Conclusion

This article proposes a multidisciplinary and multi-objective topology optimization design method based on the concept of structural/thermal integration, starting from the development requirements of diagonal second level star sensor brackets for high-resolution optical satellites. A multidisciplinary multi-objective optimization mathematical model was established, and a new cylindrical star sensor bracket was designed using this method. The structural mass is 0.269 kg, the lightweight rate is 47.5%, and the pointing accuracy is 2.71 “. Vibration response tests and thermal stability tests were conducted on the optimized support, verifying the feasibility of multidisciplinary multi-objective topology optimization methods in high-precision sensitive device structural design. This optimization method can solve the collaborative optimization problem of multiple objectives and domains that traditional optimization methods cannot consider in practical applications, broaden the scope of considering design factors, and obtain the optimal solution of multiple performance indicators under constraint conditions, adapting to the rapid development of aerospace technology. It is of great significance for improving the performance indicators of high-resolution optical satellites. In addition, the design method and structure proposed in this article have been applied in a certain satellite, and the optimization method has certain reference significance for the structural design of other satellites that require high pointing accuracy and attitude stability. At the same time, the structural form can provide new design inspiration for related designs.