查询词典 accelerometer

This paper introduced the structure and principle of the design capacitance micro-accelerometer.

本文介绍了电容式加速度传感器的结构，并分析其工作原理。

This paper describes a low-pass filter with adjustable bandwidth range from 100 Hz to 8 kHz for MEMS capacitive accelerometer readout circuit.

提出了一种适于MEMS电容加速度计读出电路带宽可调的低通滤波器，带宽调节范围为100~8000 kHz。

Theaccuracy of the centripetal acceleration field and the attitude accuracy of themounting workpiece plane provided by centrifuge have a direct bearing oncalibrating accuracy of the tested accelerometer.

离心机所产生离心加速度场的准确度和提供安装基准的姿态准确度直接影响被测加速度计的标定准确度。

Extracting the characteristic parameter from resonance accelerometer, the structure is optimized and the non-linear error is analyzed.

提取谐振加速度计的特征参量，进行结构尺寸优化设计和非线性误差分析。

For analysis of traditional experimental modal, hammer and shaker are often used to force the structure as the clamped-clamped beam to raise the vibration of the structure, meanwhile accelerometer is placed on the structure as a sensor, then the modal parameter could be found.

传统实验模态分析大多使用冲击鎚或激振器施加点力於结构例如固定梁，做为驱动器激发结构的振动，利用加速度计做为感测器置於结构上，以求取结构之模态参数，但传统之模态实验设备都有实验操作不易以及价格昂贵的缺点。

The four varistors form the Wheatstone full bridge. Two lateral sides of cantilever and overload protection structure are fabricated using DRIE technology. A novel overload protection curvature is designed to be similar to the cantilever bending shape which is bearing the greatest acceleration. This design increases the overload protection and improves the vibration damping of accelerometer to the critical damping.

悬臂梁两侧面和过载保护曲面采用DRIE技术加工，过载保护曲面设计成近似于冲击加速度传感器承受最大加速度时悬臂梁弯曲曲面的形状，一方面提高了悬臂梁过载保护能力，另一方面可以调节加速度传感器的工作阻尼至临界阻尼，有效提高了加速度传感器的工作频率带宽。

The effect of tribology factors on bearing vibration is studied experimentally. AR model and WPT are used to processing the normal arid abnormal signals. The results are as follows:1. The vibration of ball bearings is caused by the tribology action of contact pairs of ball and ring races and has the essential of tribo-dynamics. Any factors affecting the tribology characteristics of contact pairs will affect vibration and noise of bearings consequently.2. Vibration characteristics of bearing keep almostly unchanged with the increasing of axial load expecting the increasing of nature frequencies. When radial load increasing with axial load unchanged, nature frequencies keep unchanged but some new vibration peaks appears in the spectrum.3. Vibration amplitudes are damped and nature frequency are enhanced with sufficient lubrication. Vibration and noise of bearings increase obviously and roar can happen and the contact surfaces scratch slightly under insufficient and unclean lubrication state. Bearing will be disabled in a few minutes without any lubrication.4. Bearing vibration is unstable under low speed. With the speed increasing, the vibration become stable and natural frequencies increase slightly but the amplitudes increase apparently.5. Bearing vibration can be excited only by some harmonics ofwaviness without lubrication and by all harmonics with lubrication based on the theoretical analysis.6. The nature frequencies of ball bearings decrease with the increasing sizes. When international clearance increasing, nature frequencies decrease in radial and increase in axial and angular and the amplitudes increase in radial and decrease in axial and angular. When the number of balls increasing, nature frequencies increase and amplitudes decrease. When the pitch diameter increasing, axial nature frequency increase and others nearly keep no change. When outer race groove curvature radius increasing, nature frequencies increase in radial and decrease in axial and angular and amplitudes keep no change in radial and increase in axial and angular. When inner race groove curvature radius increasing, nature frequencies decrease and amplitudes increase.7. The distortion in amplitude and frequency components of bearing vibration signals picked up by the present probe measurement method is founded and right conclusions cannot be achieved by the signals. When accelerometer is rigidly screwed with steel stud onto a flat outer surface of a ball bearing, vibration signal can be got without distortion and the reliability of research on bearing vibration is assured.8. AR model is suitable for large samples of bearing vibration signals, square root of length of samples can be used as the upper limitation of order determination and the FPE order selection criterion is effective. Many advantages of AR spectrum are founded over the classical based on FFT.9. Time-Frequency analysis is necessary for abnormal noise of ball bearings. WPT overcomes the principle shortcomings of STFT and proved to be a best tool to process the abnormal signals.

理论分析和试验研究表明： 1球轴承振动是钢球—滚道接触副中的各种摩擦学作用引起的，具有摩擦动力学的本质，任何对接触副的摩擦学特性有影响的因素都将对球轴承的振动和噪声特性产生影响； 2中心轴向载荷作用下，载荷增大使球轴承的固有振动频率升高，载荷越大同样的载荷增幅引起的频率升幅减小，足够大的中心轴向载荷作用下载荷的变化对球轴承振动的频率特性不会产生明显的影响； 3轴向和径向联合载荷作用下，径向载荷不大时球轴承振动的固有频率基本不变，但是可能引起变刚度激励的非线性振动，出现新的频峰，过大的径向载荷将使部分钢球脱离接触，使球轴承的振动和噪声呈现不稳定状态； 4润滑对球轴承的振动和噪声特性有重要的影响，良好的润滑对振动有明显的抑制作用，润滑不充分时，振动和噪声的水平会有明显增高，一定条件下还会激发接触副中的谐振，发出啸声，造成接触表面的伤害，无润滑干接触时，短时的运转就会损伤接触副表面，使振动和噪声迅速增大，并随时可能引发严重的磨损和卡滞失效；接触副润滑良好时，油膜的"刚化效应"使球轴承振动的固有频率有所提高，润滑剂中含有弥散性污浊时，振动的幅度总体升高，但弥散性污浊不会改变球轴承振动的频率特性；浙江大学博士学位论文：球轴承振动的研究 5低速时，球轴承振动的基本特征呈现不稳定状态，随着转速的提高，球轴承振动的频率特性趋于稳定，固有频率频峰升高； 6理论分析表明，干接触时钢球和滚道表面波纹度的某些谐波分量能激励球轴承的振动，振动的幅值与谐波幅值成正比，实际球轴承中钢球的分布不可能完全均匀，波纹度的激励作用会随时发生；润滑接触的分析表明，波纹度的任意谐波分量均能激励球轴承的振动； 7球轴承的几何和结构参数分析表明，球轴承尺寸越大，径向、轴向和角振动的固有频率越低；钢球中心圆直径增大，球轴承的径向和轴向振动的固有频率基本不变，角振动的固有频率有所上升，振动的幅频特性基本不变；径向游隙加大使球轴承的径向振动固有频率降低，轴向和角振动的固有频率有所升高，径向振动幅频特性的幅值升高，而轴向和角向降低；钢球的数量增多使球轴承振动的固有频率上升，幅频特性的幅值下降，径向振动的幅值下降最为明显；外圈沟曲率半径系数增大使球轴承径向振动的固有频率升高，轴向和角振动的固有频率降低，径向幅频特性基本不变，轴向和角向幅频特性幅值升高；内圈沟曲率半径系数增大使径向、轴向和角振动固有频率均下降，振动幅频特性的幅值均有升高； 8试验对比表明，传感器采用探针式安装时，由于探针接触副接触特性的影响，钡(量得到的球轴承振动信号有失真，采用专门设计和制作的试验球轴承，以固定式安装加速度计，首次测量得到了球轴承振动的真实信号，通过对振动信号的分析，验证了球轴承振动的理论模型； 9)基于时间序列分析的AR模型适用于大样本球轴承振动信号的分析，以样本长度的均方根值作定阶上界，FPE做判阶准则，给出的AR谱光滑，频率分辨率高，是球轴承振动分析的简便而可靠的手段； 10以时频域分析的小波包变换分析球轴承异音信号能够比较好地定位和聚焦异音发生的时间，时间间隔，频率范围，同样是球轴承振动分析的可靠的手段，可用作球轴承故障诊断技术。

On moving base, a new initial alignment algorithm for strapdown inertial navigation system is proposed. In the algorithm, two special inertial frames, the initial-time inertial frame (i0 frame) and the initial-time SINS body inertial frame (ib0 frame), are defined and are selected as calculation reference frames, then, the calculation of initial alignment direction cosine matrix is expanded into three parts:(1) the DCM between i0 frame and the navigation frame will be easily obtained via local geographical coordinates and initial alignment time;(2) attitude updating using gyro samples gets the DCM between SINS frame and ib0 frame;(3) by explaining SINS specific force equation in SINS body frame, the relation between velocity log, accelerometer measurement and gravity acceleration is established to achieve the constant DCM from ib0 frame to i0 frame.

在运载体运动情况下，提出了一种适用于捷联惯导系初始对准的新算法，该算法以惯性空间为参考基准，即建立了初始时刻惯性坐标系（i0系）和初始时刻捷联惯组惯性坐标系（ib0系）两个惯性坐标系，将初始对准姿态矩阵的实现分解为三部分：（1）通过地理位置和初始对准时间求解i0系至导航坐标系的变换矩阵；（2）使用姿态更新算法实时计算捷联惯组相对于ib0系的变换矩阵；（3）通过惯导比力方程变形，获得测速仪辅助测量、加速度计输出和重力加速度之间的关系，从中可以求解出从ib0系至i0系的常值变换矩阵。

Resolution is related to the accelerometer's minimum discernable signal.

分辨率是相对于加速表的最小可辨别信号。

Firstly, the relevant features of three kinds of structure such as CMSA, PMSA, FMSA are summarized and compared ,and the advantages of finger-shaped variable-capacitance micromechanical accelerometer on the base of bias stationary structure are presented.

并以该结构为分析对象，从加速度计的分辨率、量程、稳定性、灵敏度等性能分析比较了多种结构梁，提出了折叠梁的综合性能最好，最后通过分析计算出了折叠梁在检测方向的刚度。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了