MEMS矢量水听器的温度特性及其补偿方法研究

文中以MEMS矢量水听器为研究对象,分析其温度特性,采用BP神经网络方法进行温度补偿。海水的温度范围为-2~30℃,在该范围内对水听器的温度特性进行测试。测试结果表明:随着温度的变化,MEMS矢量水听器产生温度漂移,使其灵敏度发生浮动,这样严重制约了水听器的测量精度和应用范围。采用BP神经网络算法对水听器进行温度补偿,将水听器测量电压值和实时温度进行数据融合,削弱了环境温度的影响。补偿后,水听器的温度漂移显著降低,不同工作温度下的灵敏度曲线高度重合,灵敏度浮动不超过2 d B。     

基于温度补偿的甲烷检测系统设计与实现

由于现场农田环境的复杂多变性,红外甲烷传感器所测数据的准确性和稳定性受外界环境温度影响较大,因而由温度造成的浓度测量偏差需要补偿。分析温度对浓度测量的影响,采用温度、浓度控制单一变量法,对同一浓度甲烷标准气体在不同温度下作标定实验,研究红外甲烷传感器输出值随温度变化关系,得到补偿温度影响率,结合补偿数据处理算法得到补偿值。针对不同浓度的甲烷气体,进行温度特性实验和温度补偿数据处理,实验结果表明:温度补偿前最大测量误差为0.2%,经补偿后,甲烷浓度测量值随温度变化较小,误差范围为0~0.02%。补偿后传感器稳定性和准确性得到改善,能检测0~5%浓度甲烷气体,检测精度可达40×10-6,满足对CH4气体实时监测需求。     

基于环境温度反馈的卡塞格林望远镜自动调焦

为了在望远镜设备探测过程中实时调节由环境温度变化引起的光学系统组合焦距偏离,建立了温度与成像焦点位置调节的对应关系。通过理论计算得出卡塞格林望远镜系统组合焦距变化与温度变化的关系,利用步入式可编程高低温箱设计了温度实验,得出系统单位温度焦点位置的变化量,并在实际工作环境下进行了二次标定,得出望远镜设备的离焦量为-0.14 mm/℃。最后,结合理论实验设计了一种基于环境温度反馈的望远镜自动调焦装置,应用于设备外场观测实验,得出自动调焦装置使用前后望远镜系统的成像信噪比。实验结果表明,离焦量与温度变化量具有相关性,调焦装置使用后所成图像的均方根误差由5.056降低为0.729,成像信噪比由41.09提高到49.50。环境温度反馈的自动调焦技术有利于望远镜设备更好地捕捉观测目标,抑制背景噪声,提高信号采集的精确度与参数测量的准确度,增强了外场探测对环境温度变化的适应能力。     

压阻式压力传感器温度误差的数字补偿技术

压力传感器性能易受温度变化的影响,产生零点温度漂移和灵敏度温度漂移,从而增加了测量结果的误差.根据压阻式压力传感器温度误差分析,提出了基于MAX1457芯片的数字补偿技术,对温度误差进行补偿,并运用到多个压阻式压力传感器上,在特定的温度允许下进行补偿.结果表明该种方法补偿精度高、稳定性好,有效地抑制了温度漂移.     

基于ATmega16的压力传感器温度补偿智能化设计

针对硅压阻式压力传感器的温度漂移现象,提出了一种压力传感器温度补偿智能化的设计方法。该设计以ATm ega16为核心芯片,以CS5532为模数转换器,整个电路选用低温漂的元件,并且在软件补偿中采用二次曲面法。实验温度范围为-30~55℃,经过反复实验,得出智能传感器在不同温度下最大测量误差为0.29%的结论。实验结果表明:此智能化的设计可以很好地补偿压力传感器的温度漂移,提高传感器的性能及测量准确度。     

常温下硅微谐振加速度计零偏稳定性的提高

考虑环境温度会影响硅微谐振加速度计(MSRA)的测量精度,本文研究了谐振梁的频率漂移及抑制方法以便提高其在常温下的零偏稳定性。针对结构热膨胀导致的应力进行了建模仿真,并根据仿真结果优化设计了一种低热应力的双端固支梁的结构来降低热膨胀系数不匹配带来的频率漂移。实验测得新结构的单梁谐振频率的温度系数从典型结构的约30Hz/℃降为-1.5Hz/℃,与仿真结果-1.14Hz/℃基本一致。为了进一步提高该加速度计的零偏稳定性,设计了一种高精度测温电路用来补偿温漂,该电路测温灵敏度为96.25mV/℃,测量噪声约为0.000 2℃。实验结果表明,采用优化后的结构结合线性温度补偿的方法,可使该硅微谐振加速度计的1h零偏稳定性在常温下达到10μg以下,比改进前实验室获得的52μg水平提升了80%,满足了高精度加速度测量的要求。     

基于BP神经网络的霍尔式金属浮子流量计温度补偿方法

在恒温实验装置上,对霍尔式金属浮子流量计的温度漂移进行了实验研究.研究了温度对金属浮子流量计的敏感元件(霍尔元件)的影响.在实验的基础上,提出一种基于BP神经网络的霍尔式金属浮子流量计温度补偿算法,并与多项式的拟合结果进行对比.通过仿真比较,证明该方法具有较高的补偿精度,适合于补偿环境温度对霍尔式金属浮子流量计的影响.     

液压缸行程测量系统的零点漂移补偿

在以活塞杆为标尺的液压缸行程测量实验中发现,受传动间隙、活塞杆表面加工质量及环境温度等因素的影响,测量系统的输入信号常伴有零点漂移。这导致细分辨向电路输出脉冲间隔发生变化,影响测量结果准确性。本文提出了使用数字式零漂补偿技术,采用递推平均滤波算法与极值平均算法对零漂信号进行纠正。同时使用单片机PIC16F876对该算法予以实现。     

基于32位∑-ΔADC的高精度测温系统设计及误差分析

为了满足反应量热仪中对样品温度的高精度检测要求,以32位∑-Δ型模数转换器AD7177-2为核心,设计了基于阻值比较法的铂电阻高精度测温系统,采用电流激励换向技术,消除电路中存在的寄生热电动势及系统漂移对测量的影响;提出了基于阻值标定的共模误差修正方法,提高了测温准确性。实验结果表明:系统在-100～500℃范围内,修正后的测温误差由0.28℃减小至0.01℃,不同环境下的测温精密度优于±0.001℃,满足反应量热仪的测温精度需求。     

图像式路基沉降监测系统的温度补偿方法

为减小图像式路基沉降监测系统中温度变化对测量结果的影响,通过对其核心设备—CMOS 工业相机的温度漂移进行 研究,提出一种针对该监测系统的温度补偿方法。 首先,分析说明了温度变化会对监测系统测量精度造成影响;然后,建立漂移 参数补偿模型并设置实验进行验证。 漂移参数补偿模型使相机的像点误差从 1. 0~ 2. 5 pixel 降低到 0. 1~ 0. 4 pixel,验证了该模 型的正确性;同时设置对比实验,与系统辨识的方法相比,两种方案补偿效果接近,但提出的补偿方法过程简单,更具实用性;最 后,提出路基沉降监测系统的温度补偿方法并验证。 结果表明,该方法能够提高监测系统测量精度。 所提补偿方法,对于提高 图像式路基沉降监测系统的测量精度具有重要意义。     

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.