【作者】 张云；

【导师】 李醒飞；

【作者基本信息】 天津大学 ， 仪器科学与技术， 2018， 硕士

【摘要】 空间结构微角振动是限制对地观测系统空间分辨率和平台姿态稳定度的重要因素之一。与传统陀螺仪相比,磁流体动力学(Magnetohydrodynamic,MHD)角速度传感器兼具亚微弧度测量精度和千赫兹带宽的优点,尤其适用于空间结构微角振动的测量。由于MHD角速度传感器内部的敏感元件输出信号微弱,易受噪声干扰,为保证传感器的低噪声特性,本文针对传感器微弱信号低噪声提取方法进行了如下研究:首先,研究了MHD角速度传感器敏感元件模型的低噪声设计方法,在此基础上设计了一种使用有源分立器件并联方式的直接耦合放大电路,来改善放大电路的噪声性能。噪声测量实验表明该直接耦合放大电路的等效输入噪声为(?)量级。其次,提出了一种基于磁场调制的传感器微弱信号提取方法,解决直接耦合放大电路易受运算放大器1/f噪声和其它低频噪声干扰的问题,拟通过调制磁场实现MHD角速度传感器输出信号的幅度调制。最后,设计了MHD角速度传感器的磁场发生装置,用于生成交变磁场。设计了一种增益可自动调节的磁场驱动装置,解决了交变磁场幅值易受外界干扰不稳定问题,系统测试表明螺线管生成的磁场频率为10.6kHz,磁感应强度幅值有效值为16.9mT,满足了理论设计要求,为基于磁场调制的微弱信号提取提供了稳定的高频载波信号。更多还原

【Abstract】 The micro-angular vibration of spatial structure is one of the important factors limiting the spatial resolution of ground observation system and the attitude stability of platform.Compared with conventional gyroscopes,magnetic fluid dynamics angular velocity sensors have the advantages of sub-radian measurement accuracy and kHz bandwidth,especially for the measurement of micro-angular vibration of spatial structures.Because the output signal of the sensitive components inside the MHD angular velocity sensor is weak and susceptible to noise interference,in order to ensure the low noise characteristics of the sensor,the following design methods for the low noise extraction of weak signal of the sensor are studied:Firstly,the low-noise design method for the MHD angular velocity sensor model is studied.A direct-coupled amplifying circuit that uses the parallel method of active discrete devices to improve the noise performance of the integrated operational amplifier is designed.Noise measurement experiments have shown that the equivalent input noise of the direct coupled amplifier circuit is of the order of (?) magnitude.Secondly,a weak signal extraction method based on magnetic field modulation is proposed,which solves the problem that the amplifying circuit based on direct coupling is susceptible to interference from the 1/f noise of operational amplifier and other low frequency noise.It is proposed to realize the amplitude modulation of the output signal of MHD angular velocity sensor by magnetic field modulation.Finally,the magnetic field generator of MHD angular velocity sensor is designed to generate a stable alternating magnetic field.A magnetic field drive device with automatic gain can be designed to solve the problem that the amplitude of alternating magnetic field is susceptible to external interference instability.The system test shows that the magnetic field frequency generated by the solenoid is 10.6kHz,the effective value of the magnetic induction intensity is 16.9mT,which satisfies the theoretical design requirements and provides a stable high frequency carrier signal is provided for weak signal extraction based on magnetic field modulation.更多还原