To better complete various missions, it is necessary to plan an optimal trajectory or provide the optimal control law for the multirole missile according to the actual situation, including launch conditions and target...To better complete various missions, it is necessary to plan an optimal trajectory or provide the optimal control law for the multirole missile according to the actual situation, including launch conditions and target location. Since trajectory optimization struggles to meet real-time requirements, the emergence of data-based generation methods has become a significant focus in contemporary research. However, due to the large differences in the characteristics of the optimal control laws caused by the diversity of tasks, it is difficult to achieve good prediction results by modeling all data with one single model.Therefore, the modeling idea of the mixture of experts(MoE) is adopted. Firstly, the K-means clustering algorithm is used to partition the sample data set, and the corresponding neural network classification model is established as the gate switch of MoE. Then, the expert models, i.e., the mappings from the generation conditions to the optimal control law represented by the results of principal component analysis(PCA), are represented by Kriging models. Finally, multiple rounds of accuracy evaluation, sample supplementation, and model updating are conducted to improve the generation accuracy. The Monte Carlo simulation shows that the accuracy of the proposed model reaches 96% and the generation efficiency meets the real-time requirement.展开更多
针对概念设计阶段机翼设计需要大范围探索设计空间并进行气动结构一体化设计的需求,提出一种基于类别/形状变换函数(class-shape function transformation,CST)的三维机翼气动结构解析参数化建模与优化方法。在二维CST基础上,推导三维CS...针对概念设计阶段机翼设计需要大范围探索设计空间并进行气动结构一体化设计的需求,提出一种基于类别/形状变换函数(class-shape function transformation,CST)的三维机翼气动结构解析参数化建模与优化方法。在二维CST基础上,推导三维CST参数化几何模型的解析函数形式,通过网格自适应离散与结构特征提取技术建立了三维机翼的气动和结构解析参数化模型,能够同时支持包括机翼几何构型、结构布局、结构尺寸、材料属性等参数的气动结构一体化快速建模与优化求解,具备几何模型大范围参数化以及气动、结构模型的建模过程自动化能力。采用该方法对某大展弦比机翼开展气动结构一体化优化设计,对比固定结构布局优化方案,优化结果梁由2个减至1个,翼肋由20个减至15个,质量相比减少26.1%。展开更多
The design of mini-missiles(MMs)presents several novel challenges.The stringent mission requirement to reach a target with a certain precision imposes a high guidance precision.The miniaturization of the size of MMs m...The design of mini-missiles(MMs)presents several novel challenges.The stringent mission requirement to reach a target with a certain precision imposes a high guidance precision.The miniaturization of the size of MMs makes the design of the guidance,navigation,and control(GNC)have a larger-thanbefore impact on the main-body design(shape,motor,and layout design)and its design objective,i.e.,flight performance.Pursuing a trade-off between flight performance and guidance precision,all the relevant interactions have to be accounted for in the design of the main body and the GNC system.Herein,a multi-objective and multidisciplinary design optimization(MDO)is proposed.Disciplines pertinent to motor,aerodynamics,layout,trajectory,flight dynamics,control,and guidance are included in the proposed MDO framework.The optimization problem seeks to maximize the range and minimize the guidance error.The problem is solved by using the nondominated sorting genetic algorithm II.An optimum design that balances a longer range with a smaller guidance error is obtained.Finally,lessons learned about the design of the MM and insights into the trade-off between flight performance and guidance precision are given by comparing the optimum design to a design provided by the traditional approach.展开更多
The dynamics of a supersonic missile with a deflectable nose are studied. To describe the effects of nose deflection on the dynamic model, theorems of momentum and angular momentum are adopted to develop the translati...The dynamics of a supersonic missile with a deflectable nose are studied. To describe the effects of nose deflection on the dynamic model, theorems of momentum and angular momentum are adopted to develop the translational equation and rotation equation, respectively. Because the exact model is complex, it is simplified. The simplified model suggests that the main influence of nose deflection on the dynamic model is due to the product of the time derivatives of the azimuth angle and the elevation angle, which makes the dynamic model an impulsive differential system. Considering the aerodynamic characteristics a numerical simulation is sufficient to show the open-loop characteristics of the missile.展开更多
基金Defense Industrial Technology Development Program (JCKY2020204B016)National Natural Science Foundation of China (92471206)。
文摘To better complete various missions, it is necessary to plan an optimal trajectory or provide the optimal control law for the multirole missile according to the actual situation, including launch conditions and target location. Since trajectory optimization struggles to meet real-time requirements, the emergence of data-based generation methods has become a significant focus in contemporary research. However, due to the large differences in the characteristics of the optimal control laws caused by the diversity of tasks, it is difficult to achieve good prediction results by modeling all data with one single model.Therefore, the modeling idea of the mixture of experts(MoE) is adopted. Firstly, the K-means clustering algorithm is used to partition the sample data set, and the corresponding neural network classification model is established as the gate switch of MoE. Then, the expert models, i.e., the mappings from the generation conditions to the optimal control law represented by the results of principal component analysis(PCA), are represented by Kriging models. Finally, multiple rounds of accuracy evaluation, sample supplementation, and model updating are conducted to improve the generation accuracy. The Monte Carlo simulation shows that the accuracy of the proposed model reaches 96% and the generation efficiency meets the real-time requirement.
文摘针对概念设计阶段机翼设计需要大范围探索设计空间并进行气动结构一体化设计的需求,提出一种基于类别/形状变换函数(class-shape function transformation,CST)的三维机翼气动结构解析参数化建模与优化方法。在二维CST基础上,推导三维CST参数化几何模型的解析函数形式,通过网格自适应离散与结构特征提取技术建立了三维机翼的气动和结构解析参数化模型,能够同时支持包括机翼几何构型、结构布局、结构尺寸、材料属性等参数的气动结构一体化快速建模与优化求解,具备几何模型大范围参数化以及气动、结构模型的建模过程自动化能力。采用该方法对某大展弦比机翼开展气动结构一体化优化设计,对比固定结构布局优化方案,优化结果梁由2个减至1个,翼肋由20个减至15个,质量相比减少26.1%。
文摘The design of mini-missiles(MMs)presents several novel challenges.The stringent mission requirement to reach a target with a certain precision imposes a high guidance precision.The miniaturization of the size of MMs makes the design of the guidance,navigation,and control(GNC)have a larger-thanbefore impact on the main-body design(shape,motor,and layout design)and its design objective,i.e.,flight performance.Pursuing a trade-off between flight performance and guidance precision,all the relevant interactions have to be accounted for in the design of the main body and the GNC system.Herein,a multi-objective and multidisciplinary design optimization(MDO)is proposed.Disciplines pertinent to motor,aerodynamics,layout,trajectory,flight dynamics,control,and guidance are included in the proposed MDO framework.The optimization problem seeks to maximize the range and minimize the guidance error.The problem is solved by using the nondominated sorting genetic algorithm II.An optimum design that balances a longer range with a smaller guidance error is obtained.Finally,lessons learned about the design of the MM and insights into the trade-off between flight performance and guidance precision are given by comparing the optimum design to a design provided by the traditional approach.
文摘The dynamics of a supersonic missile with a deflectable nose are studied. To describe the effects of nose deflection on the dynamic model, theorems of momentum and angular momentum are adopted to develop the translational equation and rotation equation, respectively. Because the exact model is complex, it is simplified. The simplified model suggests that the main influence of nose deflection on the dynamic model is due to the product of the time derivatives of the azimuth angle and the elevation angle, which makes the dynamic model an impulsive differential system. Considering the aerodynamic characteristics a numerical simulation is sufficient to show the open-loop characteristics of the missile.
