一阶数控球形反馈磁张量梯度仪动态特性研究

磁通门张量探头在非零的地磁场环境下存在稳定性差、非线性误差大等不足。为克服此类缺陷,需采用磁补偿技术使磁通门工作在零磁场环境。以提高磁通门张量探头的探测精度为目的,采用球形线圈及对应的驱动模块作为磁补偿装置,利用一阶数字控制系统的方法建立磁补偿装置的数学模型,并对其进行参数优化实现最优控制。实验结果显示,当带有球形反馈线圈磁通门张量探头的稳态误差在52.56 nT之内时,系统的带宽将扩展至4.75 Hz,该结果能够同时满足磁张量梯度仪的探测精度及带宽要求,提高了其在航空地球物理探测中的应用价值。

Research on dynamic characteristics of spherical feedback magnetic tensor gradiometer with first order digital controller

Fluxgate tensor probe has the defects of poor stability and large nonlinear error in non zero Earth''s magnetic field environment. In order to overcome these defects, magnetic compensation technology is adopted to make the fluxgate work at near zero magnetic field environment. In this paper, improving the detection accuracy of the fluxgate tensor probe is taken as the target, a spherical coil and corresponding driving module are adopted as the magnetic compensation device, a method of first order digital control system is used to establish the mathematical model of the magnetic compensation device, and the control parameters are optimized to achieve the optimal control. Experiment results show that the bandwidth of the system is extended to 4.75 Hz when the steady state error of fluxgate tensor probe with a spherical feedback coil is within 52.56 nT, and this result can meet the detection accuracy and bandwidth requirements of fluxgate magnetic tensor gradiometer, which enhances the application value of the proposed method in aerogeophysical exploration.