基于磁阻尼的超低频绝对振动检测机理研究

发布时间：2018-03-28 06:12

本文选题：超低频　切入点：绝对振动　出处：《浙江师范大学》2014年硕士论文

【摘要】：超低频绝对振动是指振动频率在1Hz以下,相对于惯性空间找不到或者没有静止参考点(即基准)的振动,例如航空飞行器,航海军舰以及大型桥梁等。实际工程应用中,对于超低频绝对振动的测量,一直难以找到较为理想的测量方式,现有的几款惯性式测振传感器,幅频响应呈高通特性,其固有频率普遍在5Hz～12Hz之间,在测量超低频时,传感器的输出信号几乎“淹没”在噪声中。本文通过对当今最受欢迎的磁电式速度传感器的力学模型入手,对其结构特性、频率特性、信噪比等进行分析和论证,发现该模型存在严重的先天不足,即很难从机械结构的设计着手降低传感器的固有频率fn=(1/2π)(?)k/m(式中k为弹簧倔强系数,m为惯性质量块的质量),减小弹簧倔强系数k,传感器极易自己晃动不停而“自激”,增大惯性质量块m,又势必要增大传感器的质量和体积,从而影响测量精度和适用广度。为此本文提出了一种利用两块永久磁铁同名端之间的斥力来代替传统传感器机械弹簧力的新设想,并把这种利用磁场力形成的阻尼取名为“磁阻尼”。基于磁阻尼的新机理,本文主要做了如下几项工作： (1)基于磁阻尼新机理的传感器数学模型及其分析； (2)磁阻尼新机理传感器配套的信号调理电路； (3)研制了一只基于磁阻尼新机理的传感器原理样机； (4)自制了一台传感器原理样机的简易超低频振动测试激励台； (5)获得了原理样机0.25Hz下,有较好信噪比的测试波形。实验波形表明,该传感器可以在超低频段获得有效的信号,且有较好的信噪比,可为进一步研究超低频绝对振动传感器提供良好的借鉴。最后,本论文对后续进一步的研究工作做了总结和展望,明确了未来的工作研究内容和方向。
[Abstract]:Ultra-low frequency absolute vibration refers to vibration frequency below 1Hz, which can not be found or has no reference point (i.e. reference) relative to inertial space, such as aeronautical aircraft, navigation warships and large bridges, etc. In practical engineering applications, It is difficult to find an ideal measurement method for the measurement of ultra-low frequency absolute vibration. Some inertial vibration sensors have high pass characteristic in amplitude and frequency response, and their natural frequency is generally between 5Hz~12Hz, when measuring ultra-low frequency, The output signal of the sensor is almost submerged in noise. This paper analyzes and proves the structure characteristic, frequency characteristic, signal-to-noise ratio and so on of the most popular magnetoelectric speed sensor. It is found that the model has serious inherent defects, that is, it is difficult to reduce the natural frequency of the sensor fn=(1/2 蟺 from the design of mechanical structure. K / m (where k is the mass of the inertia mass block with a spring stubbornness coefficient or m, if the spring stubbornness coefficient k is reduced, the sensor can easily shake itself and "self-excite", increase the inertia mass block m, it is bound to increase the mass and volume of the sensor. Thus, the measurement accuracy and the scope of application are affected. In this paper, a new idea of using the repulsive force between the two permanent magnets to replace the mechanical spring force of the traditional sensor is proposed, and the damping formed by the magnetic field force is called "magnetic damping", which is based on the new mechanism of magnetic damping. The main work of this paper is as follows:. 1) the sensor mathematical model and its analysis based on the new mechanism of magnetic damping; (2) the signal conditioning circuit of the new magnetic damping mechanism sensor; A sensor prototype based on the new mechanism of magnetic damping is developed. (4) A simple ultra-low frequency vibration test and excitation platform is made for a prototype of sensor principle. The test waveform with good signal-to-noise ratio (SNR) is obtained under the principle prototype 0.25Hz. The experimental waveforms show that the sensor can obtain effective signals in the ultra-low frequency band and has a good signal-to-noise ratio, which can provide a good reference for the further study of ultra-low frequency absolute vibration sensors. Finally, this paper summarizes and prospects the further research work, and clarifies the research content and direction in the future.
【学位授予单位】：浙江师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP212;TB523

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