Adaptive sliding mode control of modular self-reconfigurable spacecraft with time-delay estimation

The reconstruction control of modular self-reconfigurable spacecraft (MSRS) is addressed using an adaptive sliding mode control (ASMC) scheme based on time-delay estimation (TDE) technology. In contrast to the ground, the base of the MSRS is floating when assembled in orbit, resulting in a strong dynamic coupling effect. A TED-based ASMC technique with exponential reaching law is designed to achieve high-precision coordinated control between the spacecraft base and the robotic arm. TDE technology is used by the controller to compensate for coupling terms and uncertainties, while ASMC can augment and improve TDE’s robustness. To suppress TDE errors and eliminate chattering, a new adaptive law is created to modify gain parameters online, ensuring quick dynamic response and high tracking accuracy. The Lyapunov approach shows that the tracking errors are uniformly ultimately bounded (UUB). Finally, the on-orbit assembly process of MSRS is simulated to validate the efficacy of the proposed control scheme. The simulation results show that the proposed control method can accurately complete the target module’s on-orbit assembly, with minimal perturbations to the spacecraft’s attitude. Meanwhile, it has a high level of robustness and can effectively eliminate chattering.     

An approach for predicting digital material consumption in electronic warfare

Electronic warfare is a modern combat mode, in which predicting digital material consumption is a key for material requirements planning (MRP). In this paper, we introduce an insensitive loss function (ε) and propose a ε-SVR-based prediction approach. First, we quantify values of influencing factors of digital equipments in electronic warfare and a small-sample data on real consumption to form a real combat data set, and preprocess it to construct the sample space. Subsequently, we establish the ε-SVR-based prediction model based on “wartime influencing factors - material consumption” and perform model training. In case study, we give 8 historical battle events with battle damage data and predict 3 representative kinds of digital materials by using the proposed approach. The results illustrate its higher accuracy and more convenience compared with other current approaches. Taking data acquisition controller prediction as an example, our model has better prediction performance (RMSE = 0.575 7, MAPE (%) = 12.037 6 and R² = 0.996 0) compared with BP neural network model (RMSE = 1.272 9, MAPE (%) = 23.577 5 and R² = 0.980 3) and GM (1, 1) model (RMSE = 2.095 0, MAPE (%) = 24.188 0 and R² = 0.946 6). The fact shows that the approach can be used to support decision-making for MRP in electronic warfare.     

Direct ink writing of 3D-Honeycombed CL-20 structures with low critical size

3D-Honeycombed CL-20 structures with low critical size of detonation have been fabricated successfully for intelligent weapon systems using a micro-flow direct ink writing (DIW) technology. The CL-20-based explosive ink for DIW technology was prepared by a two-component adhesive system with waterborne polyurethane (WPU) and ethyl cellulose (EC). Not only the preparation of the explosive ink but also the principle of DIW process have been investigated systematically. The explosive ink displayed strong shear-thinning behavior that permitted layer-by-layer deposition from a fine nozzle onto a substrate to produce complex shapes. The EC content was varied to alter the pore structure distribution and rheological behavior of ink samples after curing. The deposited explosive composite materials are of a honeycombed structure with high porosity, and the pore size distribution increases with the increase of EC content. No phase change was observed during the preparation process. Both WPU and EC show good compatibility with CL-20 particles. Apparently high activation energy was realized in the CL-20-based composite ink compared with that of the refined CL-20 due to the presence of non-energetic but stable WPU. The detonation performance of the composite materials can be precisely controlled by an adjustment in the content of binders. The 3D honeycombed CL-20 structures, which are fabricated by DIW technology, have a very small critical detonation size of less than 69 μm, as demonstrated by wedge shaped charge test. The ink can be used to create 3D structures with complex geometries not possible with traditional manufacturing techniques, which presents a bright future for the development of intelligent weapon systems.     

Optimal design of a novel cylindrical sandwich panel with double arrow auxetic core under air blast loading

The increasing threat of explosions on the battle field and the terrorist action requires the development of more effective blast resistance materials and structures. Curved structure can support the external loads effectively by virtue of their spatial curvature. In review of the excellent energy absorption property of auxetic structure, employing auxetic structure as core material in curved sandwich shows the potential to improve the protection performance. In this study, a novel cylindrical sandwich panel with double arrow auxetic (DAA) core was designed and the numerical model was built by ABAQUS. Due to the complexity of the structure, systematic parameter study and optimal design are conducted. Two cases of optimal design were considered, case1 focuses on reducing the deflection and mass of the structure, while case2 focuses on reducing the deflection and increasing the energy absorption per unit mass. Parameter study and optimal design were conducted based on Latin Hypercube Sampling (LHD) method, artificial neural networks (ANN) metamodel and the nondominated sorting genetic algorithm (NSGA-Ⅱ). The Pareto front was obtained and the cylindrical DAA structure performed much better than its equal solid panel in both blast resistance and energy absorption capacity. Optimization results can be used as a reference for different applications.     

基于人工势场的军事态势分析模型

在基于Agent建模仿真方法的战争复杂性研究过程中,为了解决高层指挥控制Agent对军事态势自主分析判断能力的问题,引入了高等物理学中电势场的基本原理来对战场军事态势分析进行建模--并取名为人工势场.介绍了人工势场模型构建的基本原理,结合工程实践详细讨论了该模型在理论和工程实现上的一些基本问题,最后给出了基于该模型的几个简单的分析测试实例.仿真实验证明该模型用于高层指挥控制Agent的实时军事态势分析是可行的.     

武器装备可用性设计对寿命周期费用的影响及控制

可用性设计是装备综合保障分析的重要内容.合适的可用度指标不但要满足装备效能要求,还应满足费用约束条件.为了设计并选择出费效比最高的保障方案,研究了可用性设计对装备寿命周期费用的影响,提出了运用可用度门限值来控制寿命周期费用的方法,并举例说明具体的应用.最后,就保障性设计中的费用权衡问题提出了几点建议.     

无人机虚拟维修训练系统及其HLA设计

以某型无人机虚拟维修训练系统的设计为实例,采用Creator对联邦实体建模,结合动态视景仿真软件Vega Prim e进行环境与目标的驱动,基于高层体系结构HLA对系统的分布式网络互联进行仿真设计,无人机虚拟维修训练系统有效地改善了目前无人机结合实装进行操作训练的局限性。     

一种组合预测模型及预测值的模糊分级

基于多元线性回归模型及ＧＭ（１,ｎ）模型,给出了一种组合预测模型,进行了组合预测的精度分析及预测值的等级分类,并讨论了其在实际问题中的应用．     

一种控制系统的综合故障诊断方法

提出了一种控制系统的综合故障诊断方法 ,用以解决复杂系统的描述困难与诊断准确性问题。通过将控制系统故障检测与诊断分解为一个多层次的过程 ,综合应用因果网络方法与强跟踪滤波器方法 ,实现了两种方法优缺点的互补。仿真表明 ,该方法解决复杂控制系统故障检测与诊断问题是有效的     

LDPC编码跳频通信系统中的迭代抗干扰抑制算法研究

文中讨论 LDPC 码在抗干扰跳频通信中的应用问题。在接收机几乎没有任何信道先验知识(包括信噪比/信干扰比,部分频带干扰信息等)的假设下,推导了一种新的鲁棒检测算法。该鲁棒检测算法与最小和迭代解码算法结合可成功用于 LDPC 码的有效接收,性能逼近理想不可实现条件下的最佳检测算法。