超低频隔振中绝对速度信号低频带扩展技术

发布时间：2018-08-23 15:06

【摘要】：近年来由于科学技术发展,各仪器设备的精度和稳定性都不断提升,各种振动的影响变得越发突出,如何有效地隔离低频和超低频振动现已成为研究热点和难点。与被动隔振技术相比,主动隔振技术具有更小的振动传递率,并且具有更大的隔振带宽,在精密测试和超精密制造设备中都得到广泛应用。磁电式振动速度传感器是主动隔振系统的重要组成部分,由于使用环境的限制,传感器不能同时满足小体积和低频信号探测的要求。因此,在不改变传感器机械结构的前提下,选择合理的补偿方案,设计满足性能要求的良好的补偿电路及补偿软件具有很高的实用价值。本文首先分析了隔振系统对传感器的性能要求,并对各类绝对振动传感器的工作特性进行了分析和比较,最终确定了关键技术指标和传感器型号。在深入分析了磁电式速度传感器的结构和工作原理的基础上,建立传感器的动力学模型,构建传感器的传递函数,得到传感器的幅频特性。根据传递函数分析传感器的低频测量局限及其原因,并且针对该局限提出传感器低频扩展方案,最后确定使用零极点补偿法对传感器进行低频扩展。由于需要更为准确的传递函数,本文还研究了磁电式速度传感器的多种测试方法,例如直流激励法、正弦激励信号法和振动台法等。分析了各种方法的优缺点,结合各种因素,决定采用直流激励法对传感器参数进行测试,设计测试的硬件电路和软件,获取传感器精确的传递函数。根据所测量得到的传递函数和零极点补偿法原理设计相应补偿硬件和软件,完成信号处理。最后搭建磁电式速度传感器参数识别实验平台,对传感器参数进行识别,实验结果表明,直流激励法中心频率测量相对误差为0.35%,阻尼比相对误差为0.92%。将测试参数用于零极点补偿网络,并进行低频信号检测实验验证扩展电路和软件对磁电式速度传感器的低频扩展功能。实验结果表明:利用硬件电路和软件方法均能够实现将传感器中心频率由4.8Hz降至0.28Hz,实现传感器低频带扩展目标。
[Abstract]:In recent years, due to the development of science and technology, the accuracy and stability of various instruments and equipments have been continuously improved, and the influence of various kinds of vibration has become more and more prominent. How to effectively isolate low-frequency and ultra-low frequency vibration has become a hot and difficult point. Compared with passive vibration isolation technology, active vibration isolation technology has smaller vibration transfer rate and larger vibration isolation bandwidth. It is widely used in precision testing and ultra-precision manufacturing equipment. Magnetoelectric vibration velocity sensor is an important part of active vibration isolation system. Due to the limitation of environment, the sensor can not meet the requirements of both small volume and low frequency signal detection. Therefore, under the premise of not changing the mechanical structure of the sensor, it is of great practical value to select a reasonable compensation scheme and design a good compensation circuit and compensation software to meet the performance requirements. In this paper, the performance requirements of the vibration isolation system to the sensor are analyzed, and the working characteristics of all kinds of absolute vibration sensors are analyzed and compared. Finally, the key technical specifications and the type of the sensor are determined. On the basis of deeply analyzing the structure and working principle of magnetoelectric speed sensor, the dynamic model of the sensor and the transfer function of the sensor are established, and the amplitude-frequency characteristic of the sensor is obtained. According to the transfer function, the low frequency measurement limitation of the sensor and its reasons are analyzed, and the low frequency expansion scheme of the sensor is put forward. Finally, the zero pole compensation method is used for the low frequency expansion of the sensor. Due to the need for more accurate transfer function, this paper also studies many testing methods of magnetoelectric velocity sensor, such as DC excitation method, sinusoidal excitation signal method and shaking table method, etc. The advantages and disadvantages of various methods are analyzed and the DC excitation method is adopted to test the sensor parameters. The hardware circuit and software are designed and the accurate transfer function of the sensor is obtained. According to the measured transfer function and the principle of zero-pole compensation, the corresponding compensation hardware and software are designed to complete the signal processing. Finally, an experiment platform is built to identify the parameters of magnetoelectric speed sensor. The experimental results show that the relative error of DC excitation method is 0.35 and the relative error of damping ratio is 0.92. The test parameters are applied to the zero-pole compensation network and the low-frequency signal detection experiments are carried out to verify the low-frequency spread function of the expansion circuit and software to the magnetoelectric speed sensor. The experimental results show that the center frequency of the sensor can be reduced from 4.8Hz to 0.28Hz by both hardware circuit and software method, and the target of low frequency band expansion can be realized.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212

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