Overall scheme optimization of BWB UAVs based on comprehensive evaluation

To improve the overall scheme optimization efficiency of blended wing body (BWB) unmanned aerial vehicles (UAVs), a model involving multi-disciplinary analysis, comprehensive evaluation, and optimization suitable for the overall scheme of UAVs in the conceptual design stage was established, in consideration of the geometric and performance characteristics of BWB UAVs. Additionally, corresponding tools were developed. The analysis of geometry, mass, aerodynamics, and stealth characteristics of the BWB UAVs in the overall scheme was performed by combining numerical analysis with engineering methods. An improved TOPSIS method was adopted to establish a comprehensive evaluation model concerning payload capacity, economy, and adaptability of UAVs. The rationality of the analysis model was verified by using several UAV schemes as calculation cases. A parallelizable subset simulation optimization algorithm was utilized to perform a traditional multi-objective optimization with the objectives of maximizing the cruise lift-to-drag ratio and minimizing the forward radar cross section (RCS), and scheme optimization based on the comprehensive evaluation was achieved with the goal of realizing the optimal competitiveness. Based on all schemes generated during the multi-objective optimization process, a parameter correlation analysis was completed, verifying the impact of wingspan, sweep angle, and twist angle on aerodynamic and stealth characteristics. The final multi-objective optimization scheme achieves a 41.6% reduction in RCS and a 3.5% increase in cruise lift-to-drag ratio. The competitiveness score of the optimization scheme based on comprehensive evaluation was improved by 44.0%.