导弹发射台可靠性评定方法的应用研究

阐述了导弹发射台质量可靠性的重要性,提出了一种导弹发射台可靠性检测评定方法。并在线性回归分析的基础上,通过计算机仿真验证线性回归分析检测方法的可行性,证明回归分析检测法能够很好地验证导弹发射台的可靠性。     

基于过程集成的电磁轨道炮脉冲电源多目标优化

利用数值仿真方式研究电磁轨道炮脉冲电源系统——多级电容储能系统。首先利用系统仿真软件Simplorer V7搭建脉冲电源模型,进而仿真观察发射过程。弹丸发射速度和脉冲电源系统效率是设计者最关注的两个目标,而导轨及电枢材料又限制了弹丸的最大加速度,因此有必要找出在一定储能下的最佳参数配合(弹丸质量、各级储能段触发时间),使得弹丸发射速度最大,同时系统有较高的效率。本文基于过程集成的思想,使用优化软件iSIGHT,应用解决多目标优化问题的优秀算法——NSGA-II来求解上述的多目标问题的Pareto最优解。优化后的参数配置明显提升了发射速度,同时提高了系统效率。Pareto解集的多样性也给设计者在权衡速度和效率时更大的选择范围。在优化结果的基础上,对弹丸质量、触发间隔与发射速度、系统效率之间的关系做了进一步的讨论。     

基于磁电阻芯片的计转数模块分析与电路设计

为测量弹丸在旋转飞行过程中的转数,以确定弹丸飞行距离,设计了一种计转数电路,电路以巨磁电阻芯片为敏感元件,通过精密放大和脉冲扩展等模块将弹丸旋转圈数转换为脉冲输出。试验结果表明,当外磁场大于3μT时,计转数电路能够稳定工作,输出稳定的双脉冲,适用于转速为300~36000r/min的旋转弹丸,计转数模块的发射死角为2.86°。在考虑弹丸的章动和进动的情况下,可以在任何方向稳定运行,有望应用于弹丸上,实现定点起爆。     

方向可控电磁发射器拦截弹发射过程研究

方向可控电磁发射技术是主动电磁装甲防御体系的关键技术.文中分析了方向可控电磁发射器的组成及工作原理,推导了其工作过程的电路方程、拦截弹受力方程和运动学方程,建立了拦截弹发射过程的数学模型,给出了拦截弹加速过程分析的数值方法;编制有限元分析程序对拦截弹的发射过程进行了仿真,得到了加载瞬间拦截弹的速度和位移随时间变化的规律.为了对仿真结果进行验证,进行了拦截弹发射实验,测得了拦截弹的发射初速,结果表明:实验数据与仿真结果符合较好.     

Precision motion control of a small launching platform with disturbance compensation using neural networks

A kind of launching platform driven by two permanent magnet synchronous motors which is used to launch kinetic load to hit the target always faces strong parameter uncertainties and strong external disturbance such as the air current impulsion which would degrade their tracking accuracy greatly. In this paper, a practical method which combines adaptive robust control with neural network‐based disturbance observer is proposed for high‐accuracy motion control of the launching platform. The proposed controller not only accounts for the parametric uncertainties but also takes the external disturbances into account. Adaptive control is designed to compensate the former, while neural network‐based disturbance observer is designed to compensate the latter respectively and both of them are integrated together via a feedforward cancellation technique. A new kind of parametric adaptation and weight adaptation strategy is designed by using the linear combination of the system's tracking error and the weight estimation error as a driving signal for parametric adaptation and disturbance approximation. The stability of the novel control scheme is analyzed via a Lyapunov method and this method presents a prescribed output tracking performance in the presence of both parameter uncertainties and unmodeled nonlinearities. Extensive comparative simulation and experimental results are obtained to verify the high‐performance of the proposed control strategy. Copyright © 2016 John Wiley & Sons, Ltd.     

三级线圈炮发射系统设计

文章利用了Maxwell 16.0对感应型线圈炮进行仿真分析,通过对铝弹触发位置、铝弹外径的仿真分析,设置合理的仿真参数,得出三级线圈炮发射仿真结果;在仿真结果的基础上,以FPGA为控制器,设计了电磁炮发射主电路、开关控制电路以及光电测速电路,构成了电磁线圈炮实验平台;通过多次实验及分析,实验结果与仿真相符,验证了实验平台的可行性及仿真的合理性。     

平面螺旋线圈电磁发射器发射过程的动态仿真

电磁发射器发射拦截弹的过程是一个电磁学与运动学交互影响的复杂动态过程,该文以储能脉冲电容器驱动的平面螺旋线圈电磁发射器为例,利用Ansoft有限元软件中的2D瞬态求解器对电磁发射器的发射过程进行了动态仿真。建立了描述电磁发射器动态发射过程的数学模型,然后对平面螺旋线圈电磁发射器的发射过程进行仿真,并利用实验装置进行了发射实验,验证了仿真思路和仿真结果的可行性。     

磁阻型四级线圈发射器控制系统的优化及实验研究

针对磁阻型线圈发射器的电流过渡过程和涡流效应对发射器的不利影响,借助SIMPLORER和Maxwell仿真软件,对发射器的控制系统进行了优化,基本消除了这两种不利影响,提高了发射器驱动电压,最后仿真得到了不同电压下发射器的性能曲线,并完成了实验数据的采集.在204 V电压下,可把质量130 g的铁磁材料弹丸加速到19.16 m/s,30 g的铁磁材料弹丸加速到23.09 m/s.     

电感储能连续脉冲电源驱动电磁发射系统仿真

为探索连续电磁轨道发射用超导电感储能脉冲电源,建立基于单模块高温超导脉冲变压器的连续脉冲电源电路,对脉冲电源电路驱动电磁发射系统的不同放电阶段进行数学建模,仿真分析电路参数对电磁发射特性的影响,最后实验验证脉冲电源的可行性。仿真中基于储能27.72 kJ的单模块的高温超导脉冲变压器,当耦合系数为0.95,转换电容为400μF,副边电感为9.2μH,抛体质量为21.61 g时,得到510 m/s的发射速度,原边电感在放电结束后可回收剩余能量6 kJ。结果表明基于高温超导脉冲变压器的连续脉冲电源用于电磁发射系统是可行的,并有利于系统能量利用效率的提高和连续电磁发射的实现。     

Development of High‐Acceleration Linear Motor to Realize Resource Saving and High Productivity

The use of linear motors has been rapidly increasing in recent years in response to the rising demand for drive mechanisms with higher speed and acceleration to improve the throughput of semiconductor production equipment, machine tools, and so on. In this study, we have developed a new type of linear motor with an opposed magnetic pole structure and twin movers. To achieve higher acceleration of a linear motor, it is necessary to satisfy both large thrust and low inertia. In our proposed new type linear motor, the thrust is improved by increasing the facing area between the permanent magnets and magnetic pole teeth by using multistage movers. Furthermore, the magnetic leakage flux is reduced by multiplexing the magnetic flux path. In a short stroke (approximately 210 mm) drive, the high acceleration of 1670 m/s² and maximum velocity of 14.2 m/s is demonstrated using a prototype linear motor (maximum thrust = 25 kN).     

单级同步感应线圈炮结构参数研究

针对单级同步感应线圈炮系统中影响弹丸速度和系统效率的主要因素——驱动线圈和电枢的结构参数、电容器的电容和放电电压以及电枢的触发放电位置,笔者对不同结构参数的单级同步感应线圈炮物理模型进行有限元分析与仿真,得出各项结构参数对弹丸速度的影响规律,提出了一组最佳的结构参数并根据优化的结构参数进行了发射实验。仿真和实验结果均表明该结构参数可以有效地提高弹丸速度和系统效率。     

火炮发射次数检测系统设计

针对火炮发射现场实时记录问题,本文设计一种基于单片机的火炮发射次数计数系统.该系统通过应用处理器C8051F060以及其外围电路,对振动传感器MEAS3031采集到的振动信号和音频传感器采集的声音信号进行处理,与设定阈值比较后得到相应的发射脉冲,实现次数的准确统计.在实验平台上对振动和声音信号的具体形式进行分析,结果表...     

三级重接式电磁发射系统的仿真与实验

重接式电磁发射是一种利用磁力线重接来推动发射体前进的电磁发射形式,发射体受力正比于线圈电感梯度与回路电流二次方的乘积.设计建造了三级重接式电磁发射实验系统,该系统使用箱形线圈和板状发射体,并采用脉冲电容器组作储能元件.基于重接式电磁发射的电路方程和运动方程,并结合实验系统参数的实测与拟合,用四阶Runge-Kutta法建立了发射体运动过程的数值仿真模型.实验结果与仿真所得运动规律相一致.在三级发射过程中,发射体经历三次加速,每次加速都在各级电容器组向线圈放电后很短的时间和距离内完成,发射体终速度明显随电容器组初始充电电压增大而增大.当电容器组初始充电电压为4000V时,质量为160g的发射体获得的三级发射终速度为27.1m/s.     

Surface switching characteristics of variable permittivity dielectrics

Flashover voltage, lifetimes, and switch performance of insulators utilizing square thin and thick film electrodes were examined to determine the viability of using thin electrodes for reliable surface discharge switching. Gold, silver, and platinum were sputtered (0.25 /spl mu/m) and screen printed (15 /spl mu/m) onto Al/sub 2/O/sub 3/, TiO/sub 2/, and modified BaTiO/sub 3/ (MBT), then tested in air at 10/sup 5/ Pa, under vacuum (10/sup -3/ torr), and while immersed in an insulating fluid, SF-2 (manufactured by 3M). For the measured range of 0.5 to 3 mm in air, the flashover voltage for all three insulators was found to have a linear dependence on the electrode separation distance with 15 /spl mu/m thick screen printed electrodes and a square root dependence with 0.25 /spl mu/m thick sputtered electrodes. Delay times of approximately 20 ns with a corresponding jitter of 6 ns were observed across all three insulators under triggered flashover. Insulators in air with sputtered electrodes had lifetimes of approximately 5 flashovers for dc flashover and 40 for triggered flashover. Screen printed TiO/sub 2/ and MBT had dc lifetimes of approximately 10 flashovers in air, and 3 flashovers in vacuum and SF-2. Screen printed TiO/sub 2/ and MBT had triggered lifetimes of greater than 200 flashovers in air, and <3 flashovers in vacuum and SF-2. Screen printed Al/sub 2/O/sub 3/ had dc and triggered lifetimes of greater than 200 flashovers in air, vacuum and SF-2. Insulator failure during dc flashover was determined to be due to the formation of a conductive channel between the anode and cathode. Formation of the channel was attributed to insulator thermal and dielectric properties and the presence of vaporized electrode species in the gap region during flashover.     

直线式振动能/电能转换器的结构优化

设计了一种用于回收振动能的低频直线式振动能/电能转换器.利用Ansoft电磁场有限元软件,以空载感应电动势幅值为对象,对动子磁铁的排列方式和尺寸及绕组的尺寸进行了优化.最终得到的模型重量为0.5kg,体积为0.4×10-3 m3,动子运动的有效利用率为100%.动子运动速度为0.25 m/s时产生的感应电动势幅值为9....     

Microprocessor-Based Adjustable-Speed DC Motor Drives Using Model Reference Adaptive Control

Model reference adaptive control (MRAC) is applied to microprocessor-based adjustable-speed dc motor drives. The algorithm of the MRAC is based on the linear model following control (LMFC) and is the combination of the adaptive controller with the LMFC. The MRAC-based speed controller allows the indistinctness and/or inaccuracy in the motor and load parameters in the system design stage. It also maintains the prescribed control performance in the presence of the motor parameter perturbations and the load disturbances. The experimental setup is constructed using a microprocessor. The experimental results confirm the useful effects of the MRAC-based speed controller.     

环境风对直接空冷系统换热性能影响的研究

以某台600 MW直接空冷机组为例,采用数值模拟的方法,研究不同环境风速、风向对直接空冷系统性能的影响.研究结果表明,在汽轮机排汽参数一定时,随着环境风速增大,冷却风量及空冷凝汽器换热量减小；炉后风对直接空冷系统性能影响大于其它风向.当炉后风风速增至10 m/s时,迎面风速由无风时的2.1 m/s降为1.78 m/s,空冷凝汽器换热量为无风环境下的82.8％,机组发电能力显著降低.     

Control and protection scheme of HVDC system with self‐commutated converter in system fault conditions

For extending self‐commutated converter application to future trunk power systems, it is important to develop a stable operation scheme as well as to realize substantial cost reduction through coordinated system and control design. Suppression controls of converter overcurrent and dc overvoltage in various system fault conditions are essential in order to ensure stable operation and cost reduction of HVDC systems with voltage source type self‐commutated converters. Converter control and protection schemes which include such suppression controls have been developed, employing CRIEPI's ac/dc Power System Simulator test and EMTP analysis. This paper first discusses the cause of converter overcurrent at ac system faults, considering the effect of PWM pulse number and converter control speed. Continued operation has been achieved by adding a new overcurrent suppression scheme to the converter control. In the case of a dc line grounding fault, the selection of the grounding circuit constant and the adoption of a high‐speed converter control practically ensure the reduction of dc overvoltage while suppressing converter overcurrent. The converter block and restart sequence after a dc fault, which is coordinated with dc circuit breaker operation, enables stable recovery of HVDC transmission as fast as the usual line‐commutated HVDC system. © 2000 Scripta Technica, Electr Eng Jpn, 132(2): 6–18, 2000     

基于磁阻传感器的高旋弹转速测量系统

由于现在战争的需要,对弹药精确打击能力提出了新的要求,传统的测量方法对高旋弹转速的测量,受器件过载、成本限制、精度要求已经无法满足工程应用的需求.地磁场作为一个有规律的稳定场,在宇宙空间探测、国防、矿场探测方面发挥着重要作用.本文提出的测量系统利用两片HMC1052,通过特殊的传感器组合方式获取地磁场信号,地磁场信号在再经过过零点结算,最终得到弹体转速.该测量系统能够解决转速高达330 r/s的高旋弹转速测量问题,经过试验验证,转速误差相对精度可以达到1.52%.     

Design and analysis of MEMS piezoresistive rectangular paddle microcantilever based wind speed sensor

Abstract

This paper presents design, simulation and finite element analysis of a wind speed sensor based on MEMS piezoresistive microcantilever. The design is based on the drag force of the wind flow on any structure and employs four piezoresistors in Wheatstone bridge configuration to provide an electrical readout. Two basic structures, diaphragm and cantilever, are designed and simulated for the wind speed range 0–35 m/s using Coventorware 2012. As the magnitude of the force exerted by the wind with a speed of 35 m/s is very small, enhancement in the sensitivity of the sensors involved is a priority and can be achieved by structural variation of the cantilever. The optimized diaphragm structure provides a sensitivity of 0.31007?mV/(m/s)V. This is increased to 0.41612?mV/(m/s)V when utilizing a simple cantilever structure. The piezoresistors are also optimized by varying their dimensions so as to provide maximum sensitivity of 0.47843?mV/(m/s)V. The cantilever structure is optimized for maximum sensitivity by introducing a rectangular paddle at the free end. The optimized sensor is simulated for the range wind speed 0-35 m/s and provides a sensitivity of 1.3156?mV/(m/s)V. MEMS based piezoresistive wind speed sensor has advantages of having a small size, low power consumption and good sensitivity over wide range of operation.