基于模糊神经网络的连轴器故障诊断方法

针对连轴器的典型故障,应用振动谱分析方法,在前期实验的基础上,总结出连轴器故障诊断的几条模糊规则,提出了基于模糊神经网络的连轴器故障诊断方法,提高了故障诊断的准确度。     

引信电子部件ESD效应和加固实验研究

利用静电放电模拟器对某电子时间引信的电子部件的损伤及其防护加固进行了实验研究。引信部件在ESD的作用下,储存的信息会改变;当ESD的电压进一步升高时,引信中的电子部件出现损坏,其损伤阈值为＋200V．采取加固措施后,系统抗ESD的电压提高了2～3倍,达到了预期的目的。     

舰船动力系统优化设计方法展望

简述了舰船动力系统优化设计的思想与内容,研究了舰船动力系统优化设计的理论与方法,提出了综合集成设计、智能优化设计等未来舰船动力系统优化设计的概念与方法     

相变材料下滑过程的接触熔化分析

本文对相变材料在斜面下滑过程中的接触熔化进行了分析。通过理论分析,求得料面保持恒温或变温对相变材料加热并使之匀速下滑时,相变材料的熔化速度、时间及固体瞬时高度。所得结果包含了前人的工作。     

东北民主联军撤出四平、长春后不被直追考

1946年5月疲惫不堪的东北民主联军主力撤出四平、长春,退往松花江北岸时,竟未被国民党军越江跟进追击。本文在对大量相关的史料综合分析后发现,这与美苏有关中国(东北)的战略意向,其中与马歇尔的实际努力关系甚大。认为当时美国方面从自身的全球利益出发,并没有一味地盲目支持蒋介石在中国(东北)大打内战。     

试论晚清军事变革对近代社会转型之影响

晚清以来,中国社会经历了由传统封建社会向近代社会的全方位社会转型,军事变革与社会转型发生着千丝万缕的联系。解读晚清军事与近代社会转型的内在联系,有利于更好的理解那段历史。     

以弱胜强 以退为进——老予军事哲学思想探析

本文从三个方面探讨<老子>军事哲学思想:一、从根本战略思想看,<老子>主张"柔弱胜刚强",其实质是认为新事物必然战胜旧事物;二、从谋略角度来考察,<老子>主张面对强敌,弱军不妨先退一步,后发制人,因而取胜;三、在前两点基础上形成的一套以弱胜强的独特战法.     

Quasi-steady aerodynamic characteristics of Terminal Sensitive Bullets with short cylindrical portion

The aerodynamic characteristics are vital for short cylindrical Terminal Sensitive Bullets(TSB)with low aspect ratio,especially in terminal trajectory.Currently,there is little research in terms of the TSB and short cylinder with two free ends,and particularly in this trajectory,where the scanning angle β and roll angle α vary over a broad range between 0° and 180°.In this work,wind tunnel experiments are first conducted to learn the effects of Reynolds number and scanning angle on aerodynamic parameters for short cylinder with aspect ratio L/D = 1.Similar to infinite cylinder,for the short cylinder with two free ends,the drag crisis phenomenon still exists in the critical regime 1.7 × 105 ≤ Re ≤ 6.8 × 105.Then 3D simulations are performed to demonstrate the aerodynamic characteristics of short cylinder and TSB over a broad range of Re,L/D,α and β.The sensitivity analysis of time step and grid are presented as well.When β=0°,for short cylinder,the drag crisis phenomenon was also observed in the simulation,but not as obvious as in the wind tunnel test.In some attitudes,there is an obvious Kármán vortex in the wake of short cylinder and TSB.The correlation between time-averaged aerodynamic coefficients and L/D,Re,α&β is discussed.The vortex shedding frequency and shear layer behavior are obtained for quasi-steady and unsteady flow.Finally,the effect of end's shape on drag reduction and vortex shedding frequency is analyzed.     

Barrier Lyapunov functions-based dynamic surface control with tracking error constraints for ammunition manipulator electro-hydraulic system

This paper focuses on the dynamic tracking control of ammunition manipulator system. A standard state space model for the ammunition manipulator electro-hydraulic system (AMEHS) with inherent non-linearities and uncertainties considered was established. To simultaneously suppress the violation of tracking error constraints and the complexity of differential explosion, a barrier Lyapunov functions-based dynamic surface control (BLF-DSC) method was proposed for the position tracking control of the ammunition manipulator. Theoretical analysis prove the stability of the closed-loop overall system and the tracking error converges to a prescribed neighborhood asymptotically. The effectiveness and dynamic tracking performance of the proposed control strategy is validated via simulation and experi-mental results.     

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.