Optimization Design On The Structure Of Flexible Solar Arrays Based On Coupling Dynamics Analysis

As the key equipment of the power supply system in space,the solar array is the basic guarantee for the realization of the spacecraft's function and on-orbit operation.The failure of the solar array will come with a high price.It may result in the decline of the spacecraft's mission performances,greatly reduce the life of the spacecraft,and even lead to the failure of the spacecraft.The failures of solar arrays can be divided into two categories: The first one is the structural damage caused by unable to withstand the mechanical environment,which is commonly found in the launch stage.The second one is the attitude control problem caused by flexibility,which occurs in the on-orbit stage.The traditional design method often rely on empirical design,which can't effectively combine the solar array with subsystems,so it is difficult to obtain the optimal feasible solution of the structural design of the solar array.To ensure that the solar array components meet the dynamics requirements of each subsystem for each stage and ensure the reliable operation of the spacecraft,it is very necessary to carry out in-depth research on the multi-disciplinary and multi-constrained design and dynamic analysis of the solar array structure.Therefore,based on a certain type of communication satellite,this paper focuses on the following research work centred on the multi-plate deployable solar array: the establishment of the equivalent model for the multi-plate deployable solar array,the coupling dynamic analysis of the satellite attitude and the flexible solar array,the multi-disciplinary and multi-constrained optimization technology of the solar array structure and the dynamic performance testing technology of solar arrays.To meet the coupling dynamic design and analysis requirements of solar arrays,the theoretical research on the structural optimization of solar arrays was completed in this paper.According to the structural characteristics of honeycomb sandwich plates,the equivalent model was established by the sandwich theory.Besides,the cellular elements were extracted,and the equivalent elastic parameters were calculated theoretically.Then the dynamic models of the solar array and the satellite structure were further established.Based on the characteristics of structural design variables of solar arrays,a local sensitivity analysis method suitable for implicit discrete variables was proposed.Beside,and the normalization processing of nonparametric structural parameter sensitivity was realized.By improving the gradient method,the variable density optimization algorithm which is suitable for discrete variables was proposed.The algorithm can realize the fast iteration of structural design variables of the solar array.The coupling dynamics model of the satellite attitude and solar arrays was established,and the structure-attitude control coupling analysis technology was adopted to make the attitude control system participate into the structural optimization design.The dynamic model of the satellite with flexible appendages was established by using the mixed coordinate method.And the PD attitude controller was designed.Combined with the analysis results of the uncontrolled stability and PD control stability of the spacecraft,the influence of the flexibility of the solar array on satellite attitude was clarified.Meanwhile,the design requirements of the control system for the on-orbit state of the solar array were determined,so as to guide the structural optimization design.Taking a certain type of solar array as an example,the collaborative optimization of multidisciplinary and multi constraints for the solar array structure was conducted based on the structure-attitude control coupling analysis and structure-structure coupling analysis technology,According to the coupling relationship between the solar array and subsystems,combined with the parametric finite element model,the local sensitivity analysis method was used to calculate the sensitivity of the main design variables of the solar array.Based on the sensitivity analysis results,the complex constraints and variables were integrated and decomposed to determine the optimization strategy.For the on-orbit state,the dynamic model of the deployment fundamental frequency of the solar array was established.Then the initial value of the substrate's breadth-length ratio was determined through the structure-attitude control coupling optimization design.For the launch state,the component level optimization of the solar array was carried out with the optimization objectives of maximizing the stowed fundamental frequency and the coupling optimization of the solar array-satellite platform was carried out by minimizing the dynamic response respectively.The variable density optimization algorithm based on the improved gradient method was used to determine the position of supporting points.The optimization results were rounded according to the actual process requirements such as installation and configuration of battery cells,and verified by simulation analysis.A complete ground test system was designed and built to obtain the dynamic characteristics of the solar array and identify the structural parameters.Besides,combined with the non-full-scale physical test and full-scale simulation,the structural design was closed-loop.According to the mechanism characteristics of the multi-plate deployable solar array,a suspended modal test system with gravity compensation function was proposed in this paper.The mathematical model and the finite element model of the test system were established to provide technical support for test error analysis and structural parameter identification.Through a series of ground tests,the typical structural parameters of the solar array were identified.Besides,the modal information and dynamic responses of the solar array and the satellite plate were obtained through the non-full-scale physical test.Combined with the full-scale simulation analysis,the effectiveness of the structural optimization design results was verified.Based on the coupling dynamics analysis technology,this paper proposed a set of structural optimization design and dynamic analysis methods which is suitable for multi-disciplinary and multi-constrained design requirements of the multi-plate deployable solar array.These methods ensure that the solar array meets the dynamic requirements of the spacecraft's subsystems for each stage,and reduce the design pressure of the satellite platform,the load system and the attitude control system.