某装备吊机液压故障诊断专家系统设计

装备液压系统快速故障诊断是维修保障人员亟待解决的难题.以某装备吊机液压系统故障诊断为研究对象,梳理历年故障案例库,运用故障树解析故障原因、逻辑及耦合关系,明确故障产生的全部最小割集.将故障树与专家系统有机结合,依据故障规则构建基于故障树的专家知识库,选用自上而下正向查找方式的推理机制,融合概念图知识匹配模式,设计模糊含权概念图的投影匹配算法.在VB环境下实现专家系统软件功能,使系统具备知识库持续升级、用户故障定位查询、故障排除指导、历史故障记录、诊断报告生成等功能,有效指导维修保障人员进行装备液压系统的故障诊断与排除,并可推广至其他型号、类型的装备液压系统故障诊断中.     

武器装备研发成本补偿引入保险机制

随着我国军民融合武器装备研发生产体系的深度发展和社会主义市场经济体制的不断完善,武器装备研发中投入的研发成本面临很高的投资风险,成为困扰企业参与武器装备研发的重要因素。面对庞大的研发费用支出以及研发成本补偿措施不完善,企业要独自面对研发活动中的风险,这在一定程度上降低了企业参与装备研发的积极性。本文认为,通过保险机制的引入,鼓励企业为武器装备研发活动投保科技保险,同时,军方在对研发活动进行分析评判后,对企业的保费按比例进行分摊,能够在拓宽补偿途径的同时,利用保险分担企业研发过程中的风险,激发企业参与武器装备研发的热情,更好地为军队武器装备发展建设做出贡献。     

国防科技工业军民协同动力研究

国防科技工业军民协同动力研究旨在探寻国防科技工业军民协同的动力源泉。本文从国防科技工业军民协同动力演化和演化过程中所涉及的理论原理入手,分析军民协同动力机制的生成机理,论证国防科技工业军民协同动力演化的理论根源,推断得出国防科技工业军民协同动力生成具有"两条路径、三个层次、五种力量"的一般规律,认为国防科技工业军民协同动力系统由形势环境、战略决策、技术、资源和政策五种力量构成,五种力量共同作用,综合影响着国防科技工业军民协同动力的产生。深入研究国防科技工业军民协同动力理论,有助于为加快推动国防科技工业军民深度融合发展、构建国家军民一体化战略体系和能力提供理论支撑。     

基于机器学习的固体火箭发动机无损检测

传统固体火箭发动机无损检测图像判读工作存在人工识别效率低、图像数据分散及数据利用率低等问题。本文借助机器学习算法与计算机视觉技术,利用大量发动机无损检测图像数据开展无损检测图像数据预处理、边缘检测以及数据模型训练和应用等技术研究,探索快速、准确获得发动机无损检测图像数据特征的方法,深入挖掘固体发动机无损检测数据的内在联系,找到潜在规律。本研究不仅为固体发动机无损检测图像判读提供了一种准确、高效的手段,同时,能够为发动机无损检测图像识别、测量、判读和发动机相关故障模式分析与故障诊断提供数据和决策支持,也能够为未来机器学习在固体发动机无损检测图像判读领域的深入应用提供实践探索和理论研究方面的参考。     

美军联合作战实验回顾性分析

美军进行联合作战实验的目的是为了使美军在21世纪获取更大的作战能力以应对未来战争.在分析联合作战实验地位和作用的基础上,对美军联合作战实验组织方式、联合作战实验的法规形成、联合作战实验基本过程、联合作战概念开发基本过程,以及联合作战实验基本形式几个方面进行了详细阐述,给出了美军联合作战实验的几点启示.     

基于SDAE+Softmax模型的体系贡献率评估方法

战争就是交战双方作战体系之间的对抗.体系贡献率评估是体系建设和分析重点关注的问题,是对作战要素在作战体系中所发挥作用的一种度量.针对体系的复杂系统特性,构建SDAE+Softmax模型对体系效能涌现过程进行建模,模型描述了体系基础指标与任务指标之间的关系.提取Softmax分类器的分类概率相对值作为体系贡献率评估的综合特征指标,量化体系组分改变对体系效能的影响.基于SDAE+Softmax模型的评估方法,为体系贡献率评估提供了全新的思路,是对传统评估方法的突破.     

Adaptive subspace detection based on two-step dimension reduction in the underwater waveguide

In the underwater waveguide, the conventional adaptive subspace detector (ASD), derived by using the generalized likelihood ratio test (GLRT) theory, suffers from a significant degradation in detection per-formance when the samplings of training data are deficient. This paper proposes a dimension-reduced approach to alleviate this problem. The dimension reduction includes two steps: firstly, the full array is divided into several subarrays; secondly, the test data and the training data at each subarray are transformed into the modal domain from the hydrophone domain. Then the modal-domain test data and training data at each subarray are processed to formulate the subarray statistic by using the GLRT theory. The final test statistic of the dimension-reduced ASD (DR-ASD) is obtained by summing all the subarray statistics. After the dimension reduction, the unknown parameters can be estimated more accurately so the DR-ASD achieves a better detection performance than the ASD. In order to achieve the optimal detection performance, the processing gain of the DR-ASD is deduced to choose a proper number of subarrays. Simulation experiments verify the improved detection performance of the DR-ASD compared with the ASD.     

Simulation of the plasticizing behavior of composite modified double-base (CMDB) propellant in grooved calendar based on adaptive grid technology

The frequent occurrence of safety accidents during the calendering process is caused by the flammable and explosive properties of composite modified double-base (CMDB) propellant. Optimization of process parameters with the aid of fluid simulation technology could effectively ensure the safety of the calendering process. To improve the accuracy of the simulation results, material parameters and model structure were corrected based on actual conditions, and adaptive grid technology was applied in the local mesh refinement. In addition, the rheological behavior, motion trajectories and heat transfer mechanisms of CMDB propellant slurry were studied with different gaps, rotational rates and temperatures of two rollers. The results indicated that the refined mesh could significantly improve the contour clarity of boundaries and simulate the characteristics of CMDB propellant slurry reflux movement caused by the convergent flow near the outlet. Compared with the gap, the increased rotational rate of roller could promote the reflux movement and intensify the shear flow of slurry inside the flow region by viscous shear dragging. Meanwhile, under the synergistic effect of contact heat transfer as well as convective heat exchange, heat accumulated near the outlet and diffused along the reflux movement, which led to the countercurrent heat dissipation behavior of CMDB propellant slurry. The plasticizing mechanism of slurry and the safety of calendering under different conditions were explored, which provided theoretical guidance and reference data for the optimization of calendering process conditions. Based on the simulation results, the safety of the CMDB propellant calendering process could be significantly improved with a few tests conducted during a short research and development cycle.     

Finite-time tracking control and vibration suppression based on the concept of virtual control force for flexible two-link space robot

The dynamic modeling, finite-time trajectory tracking control and vibration suppression of a flexible two-link space robot are studied. Firstly, the dynamic model of the system is established by combining Lagrange method with assumed mode method. In order to ensure that the base attitude and the joints of space robot can reach the desired positions within a limited time, a non-singular fast terminal sliding mode (NFTSM) controller is designed, which realizes the finite-time convergence of the trajectory tracking errors. Subsequently, for the sake of suppressing the vibrations of flexible links, a hybrid tra-jectory based on the concept of the virtual control force is developed, which can reflect the flexible modes and the trajectory tracking errors simultaneously. By modifying the original control scheme, a NFTSM hybrid controller is proposed. The hybrid control scheme can not only realized attitude stabili-zation and trajectory tracking of joints in finite time, but also provide a new method of vibration sup-pression. The simulation results verify the effectiveness of the designed hybrid control strategy.     

Recursive weighted least squares estimation algorithm based on minimum model error principle

Kalman filter is commonly used in data filtering and parameters estimation of nonlinear system,such as projectile's trajectory estimation and control.While there is a drawback that the prior error covariance matrix and filter parameters are difficult to be determined,which may result in filtering divergence.As to the problem that the accuracy of state estimation for nonlinear ballistic model strongly depends on its mathematical model,we improve the weighted least squares method(WLSM)with minimum model error principle.Invariant embedding method is adopted to solve the cost function including the model error.With the knowledge of measurement data and measurement error covariance matrix,we use gradient descent algorithm to determine the weighting matrix of model error.The uncertainty and linearization error of model are recursively estimated by the proposed method,thus achieving an online filtering estimation of the observations.Simulation results indicate that the proposed recursive esti-mation algorithm is insensitive to initial conditions and of good robustness.