多通道隔离电流输出型变送器信号调理系统

设计了一个应用于电流输出型变送器的多通道隔离信号调理系统,它集I/V转换电路、放大电路、滤波电路、隔离设计于一体,实现了将4～20 mA电流信号转换为可被A/D采样卡采集的电压模拟信号.经实验验证,该系统转换精度高、稳定性好、抗干扰能力强,已被应用在工程实践中.     

电容式高频振动幅值测量方法研究

针对超声疲劳试验中20 kHz以上的高频振动幅值的测量问题,提出一种电容式高频振动幅值测量方法,并构建了基于该方法的测量系统。文中以振动信号处理为主线,设计基于调幅式的振动解调电路,实现传感器信号的高精度解调;设计频率自适应数字滤波器实现解调信号的动态滤波;设计基于Hilbert变换实现数字包络检波器完成振动信号幅值的精确求解。对基于此方法测量系统的精度和测量范围进行了实验验证,实验结果证明,此系统具有较高的精度和较大的测量范围,其精度优于0.3%F.S.,振幅测量范围最大可至100μm,动态频响超过20 kHz。     

基于AD8495和Sigma-Delta的多通道高精度数字测温设计

针对工业现场温度测量的特殊环境和多点温度监测的实际需求,设计了一种高精度多通道数字温度采集系统。首先根据热电偶的测温原理,设计了相应的冷端自动补偿电路、RFI射频滤波电路等,滤除高频射频信号,提高抗干扰能力。利用双定时器程序设计优化模拟开关切换和串口通信,并通过分析和验证Sigma-Delta型ADC的2种抽取滤波器的转换精度,实现高分辨率的A/D采样。对于热电偶本身的非线性特性采用分段线性拟合校正,通过上位机采集数据进行分析,符合设计要求,测温范围为-20～1300℃,测量精度优于1℃。     

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。     

基于WPM的高精度光纤Bragg温度传感系统研究与设计

根据边缘滤波器的Bragg光栅温度解调原理,利用DSP2407作为处理芯片,设计完成了光电转换和信号调理电路,构建并实验研究了低成本温度传感检测解调系统。解调系统采用双光路结构,并提出了一种对称双通道信号数据融合方案,从理论与技术上做到消除由于激光光源和光路造成光强波动带来的测量漂移问题。引入数字温度计与设计光纤光栅温度系统,利用恒温水槽进行了对比实验。实验数据表明:在环境温度对光源以及对整个系统的影响下,系统温度测量仍具有良好的稳定性与精度。     

∑-Δ A/D转换器混合电路建模方法研究

由于具有转换精度高和其他一系列优点,∑-Δ过采样A/D转换技术近年来颇受重视,而模拟和混合信号系统的硬件描述语言VHDL-AMS为其提供了一种良好的设计方法。本文根据∑-ΔA/D转换器的原理,建立了一个包括二阶∑-Δ调制器和抽取滤波器的转换器VHDL-AMS模型,同时结合Szermer提出的模型,对两种结构进行了仿真、比较和分析。     

辐射监测的微弱电流测量I-V转换技术

针对辐射测量中电离室输出极其微弱的电流信号,研发一种弱电流测量技术。利用高输入阻抗运算放大器设计了用于微弱电流测量的I-V转换采样电路和带有T型网络的I-V转换采样电路,分析研究了I-V转换电路的特点,计算分析T型网络的I-V转换采样电路的灵敏度。通过T型网络,选用高稳定输入阻抗运算放大器和高稳定反馈电阻,提高了测量灵敏度。设计电路满足辐射粒子所致的电离室输出电流为10-14A数量级时的弱电流测量。     

微型光电编码器在电机角速率辨识中的应用

针对电机伺服控制系统利用编码器角位置信息预测角速率的需求,提出并实现了一种基于平稳卡尔曼滤波的编码器信号处理方法。首先,分析了典型电机系统的结构及测量噪声编码器的组成,在此基础上建立了电机系统和编码器的参数化数学模型,并根据电机系统和编码器模型给出了统一的参数化平稳卡尔曼滤波器设计结果。在Matlab/Simulink环境下完成了电机、编码器和卡尔曼滤波器的仿真模型,并利用不同参数对参数化平稳卡尔曼滤波器的普适性和滤波效果进行了预测。最后,搭建了实验平台,对仿真结论进行验证并对滤波性能进行了实测。仿真和实验结果表明:参数化滤波模型对典型电机系统具有普适性,自适应平稳卡尔曼滤波器可以利用编码器信号实现角速率的最优估计,误差标准差为0.021(°)/s,最大误差可以控制在0.06(°)/s之内,能够满足一般电机伺服系统对角速率精度的要求。     

光纤光栅微弱信号检测的解调电路

为了在光纤光栅匹配解调系统中实现对光纤光栅微弱信号的检测与处理,在应用微弱光电信号检测原理的基础上设计一种高信噪比、高检测精度的解调电路,该解调电路采用低噪声电路元件参数选取原则和前置放大器设计的一般方法,在雪崩光电二极管与信号数模转换之间采用互阻放大器、巴特沃斯滤波电路和多级放大电路,实现了电路的最佳噪声匹配,有效地抑制了电路的噪声和干扰。该解调电路在光纤光栅匹配解调系统中具有很高的信噪比和测量精度,且具有很好的灵敏度,在测量低频率振动信号试验中具有优异的性能。实验表明:该电路解调系统在25～200 Hz正弦激励振动信号下具有很好的低噪声性能,精确的测试出振动信号,同时该电路所采用的方法与措施对其他测量系统也有借鉴意义。     

分布式光纤Bragg光栅振动加速度测量及其系统的研究

本文基于连续波调频、波分、光纤光栅测量等技术，利用分布光纤光栅阵列设计了加速度实时测量系统。系统中，利用微机械技术设计加速度测量探头；应用连续波调频技术、波分技术实现串、并联光栅信号的解调。应用扫描滤波技术实现信号的辨识。本研究可完成低频微振动加速度信号多点测量。     

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.