核磁共振陀螺磁屏蔽罩内静磁场系统优化设计

Optimization design for static magnetic system in magnetic shield of nuclear magnetic resonance gyroscopes

核磁共振陀螺作为目前世界上体积最小的导航级陀螺,受到了国内外的广泛重视。为获得高精度与大动态范围,核磁共振陀螺通常工作在磁屏蔽罩中。根据静磁场的惟一性定理,磁力线会在磁屏蔽罩表面反射,从而影响核磁共振陀螺静磁场区域的磁场均匀性。从核磁共振陀螺静磁场分布的理论分析出发,通过数学计算和计算机仿真,分析和研究了磁屏蔽罩对静磁系统的影响,通过综合调整螺线管与屏蔽罩的交互参数,对静磁系统进行了优化设计,同时还确认了螺线管加工误差对系统性能的影响。设计的核磁共振陀螺静磁系统磁场优于1.11×10^(–5),较优化前提高至少一个数量级,满足核磁共振陀螺的使用需求。

Nuclear magnetic resonance gyroscope （NMRG）, as the present smallest navigation grade gyroscopes, has been widely appreciated. In order to obtain high precision and large dynamic range, the gyroscope must be magnetically shielded. According to the uniqueness theorem of the static magnetic field, the magnetic field lines will reflect on the surface of the magnetic shield, which affects the uniformity of the NMRG＇s static magnetic field. Based on the theoretical analysis of the NMRG＇s static magnetic field distribution, the effects of the magnetic shield on the magnetic field are analyzed through mathematical modeling and computer simulation. The optimization design of the static magnetic system is carried out based on the comprehensive adjustment of the interaction parameters between the solenoid and the magnetic shield, and the effects of the solenoid＇s machining errors on the magnetic field are confirmed. The magnetic field uniformity of the magnetic resonance gyro system is better than 1.11 ×10^-5, which is at least one order of magnitude higher than that without the optimization and satisfies the requirements of the nuclear magnetic resonance gyroscopes.