水下目标存储与回波波形模拟技术的研究

本文提出了一种利用大动态范围脉冲幅度自动增益控制技术和数字波形存储技术,实现水下目标信号存储和目标回波波形模拟的方法。利用该方法设计的声纳目标应答机,经多次湖试和海试验证,技术方案可行,并取得了满意的波形模拟效果。文中主要介绍了目标信号存储与回波波形模拟的基本原理、系统时序控制关系、海试结果等。     

高精度水下目标模拟与应答技术的研究

针对模拟水下目标的回波，研究了一种对大动态范围内的声纳信号进行增益控制及应答的方法。方法采用数字波形存贮技术，数字增益控制技术，对所接收的信号波形进行处理，并采用数字波形恢复技术恢复并转发该信号，具有波形模拟逼真、应答精度高等优点。本文论述了该方法的工作原理、系统硬件实现方案及水池实验的结果。     

激光跟踪仪的光电瞄准与定位系统

考虑激光跟踪仪的光电瞄准与定位直接影响仪器的整体测量精度和使用性能,讨论了激光跟踪仪的光电瞄准和跟踪定位控制技术并提出了光电探测瞄准、信号调理采集、数字处理及智能跟踪伺服的系统整体技术方案。对系统关键部件进行选型,利用角锥棱镜和位敏探测器(PSD)作为光电探测核心,设计了探测光路和信号处理电路。研制了系统样机,搭建了目标位移量标准测试平台,对样机光电瞄准系统探测信号进行了测试。测试结果显示:采用该设计方案设计的激光跟踪仪样机的静态定位测量精度达到6μm,随机动态跟踪测量速度大于1m/s。结果表明:提出的方法可解决激光跟踪仪定位精度低、动态跟踪效果差等常见问题,可为研制高精度、大范围、大尺寸测量仪器提供技术参考。     

动态信号分析仪的应用

一、引言在现代测试技术中动态信号分析仪是重要的测试设备,既可用于系统动态特性的测量也可用于稳态分析,还可用于强度试验以及频谱分析。目前各国生产的动态信号分析仪型号规格很多性能也各异,例如有日本的CF—500,CF—920,美国惠普公司的HP3562A等等。下面以HP3562A为例介绍它的主要性能及应用。 HP3562A动态信号分析仪可用于电子、电气机械及机械系统的测量和分析,其频率范围从直流到100kHz。可进行频率特性、相关函数,功率谱和直方图测量:还可控制高速数字绘图仪对测量结果进行快速复制;以及控制外部磁盘驱动器对数据块进行贮存。     

数字闭环加速度计的带宽测试

为了测试数字闭环加速度计系统的带宽,对国军标1037A-2004中的电模拟法进行了改进。首先,讨论了用国军标1037A-2004中的电模拟法测试数字闭环加速度计带宽存在的不足,然后,对加入激励信号的数字闭环加速度计系统的检测电路及闭环控制模型进行分析。分析显示,在系统的反馈回路加入激励信号最终可以在输入端等效为外界输入加速度,且该系统的动态模型与传统机械激励测试法系统的动态模型一致。最后,提出一种在数字闭环加速度计的反馈回路外加激励信号来测试该系统带宽的方法。实验表明:数字闭环加速度计系统的实测-3dB带宽值为320Hz左右,与理论值(345Hz)基本吻合。该方法具有精度高、误差源少、便于在线测试等特点,可满足大多数数字闭环加速度计的带宽测试要求。     

基于FPGA高精度微震信号采集系统设计

微震信号动态范围大、无法预知信号幅度,直接采样接收信号会造成较大信号失真,针对该问题设计了一种自动调节增益的微震信号采集系统。该系统实时快速地根据微震信号幅度变化自动调节放大器增益,将信号调节到A/D输入范围。滤波器设计采用抽取滤波的方法,先对信号过采样,然后使用抽取滤波器对信号进行滤波和抽取,将信号数据率降低到奈奎斯特采样率,这种方法降低了对抗混叠滤波器性能的要求。通过实验验证分析,该设计能采集动态范围可达136 dB,所采集到的信号信噪比高、失真度小。     

大动态范围PGA电路的设计与实现

本文通过理论分析与实验研究，介绍了一个大动态范围ＰＧＡ电路的设计与实现过程，并从理论和实践上证明：大动态范围ＰＧＡ电路是压缩大动态模拟信号动态范围并可提高信号检测精度的一种行之有效的技术方案。     

基于数字电位器的增益自适应数据采集系统

针对某型检测系统数据采集需求,运用数字电位器可编程控制阻值功能,设计了增益可自适应调整的数据采集系统,解决了ADC输入信号幅度动态范围不稳定的问题.描述了数据采集系统的设计过程,给出了硬件设计电路和软件结构框图,详细分析了仪表放大器、增益调节放大器的工作原理和实现方法,对于类似系统和电路的设计有一定的参考价值.     

一种新型数字水听器设计

设计了一种双通道数字水听器。采用FPGA对经过放大调理的数字水听信号进行采集,采用32位微处理器STM32F107和网络接口芯片DP83848实现以太网接口的设计方法,硬件少、易于实现和使用方便,适合现在的网络传输系统。通过试验,测得系统的传输速率达到了400Kb/s,满足了水听器及水听器基阵对传输速率的要求。数字水听器信号处理能力强,提取的信息更加准确、可靠,水听器处理的信号既可通过多种总线实时同水面的电子设备进行通讯,也可作为独立的测试系统,自身进行信息的处理和保存。     

基于FPGA的简易数字信号传输性能分析系统

基于 FPGA 产生伪随机信号和曼彻斯特编码,以 MSP430为基本功能控制单元,通过三路低通滤波器和伪随机信号信道噪声来模拟传输信道,设计了一个以数字信号发生器,模拟传输信道和数字分析电路为核心的简易数字信号传输性能分析系统,实现了数字信号传输特性测试.测试表明系统工作稳定,输入信号动态范围大,眼图清晰,达到了设计要求.     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.