微推力测量中电磁力装置的性能优化

Performance Optimization of Electromagnetic Force Device in Micro Thrust Measurement

微推力测量系统对微推进器性能评估具有重要指导意义,而弱力补偿及标定作为微推力测量中的关键性环节,其稳定性、适用性、补偿精度等都直接影响最终的测量结果。针对现有电磁力标定装置输出不稳定,校准困难等问题,基于电磁力法,利用通电双线圈与永磁铁之间的相互作用力,设计了一款可封装为一体的弱力补偿装置。介绍了该电磁力装置的结构设计及优化;建立了数学模型以计算通电双线圈形成的磁场对磁芯的作用力;用Comsol仿真双线圈间的磁场分布,计算不同激励电流下磁芯的电磁力大小,并对仿真数据进行拟合分析得到电磁力的线性特性;应用精密电子天平搭建标定实验,标定数据通过最小二乘法进行线性拟合,得到决定系数为0.999,具有很好的线性特性。与仿真结果相比,效果理想,为后续微推力测量奠定了基础。

Micro thrust measurement system has important guiding significance for performance evaluation of micro thruster. As the key link of micro thrust measurement, the stability, applicability and compensation accuracy of weak force compensation and calibration direct affect the final measurement results. Aiming at the problems of unstable output and difficult calibration of the existing electromagnetic force calibration device, based on the electromagnetic force method, a weak force compensation device which can be packaged as a whole is designed by using the interaction force between the electrified double coils and the permanent magnet. The structure design and optimization of the electromagnetic force device are introduced. A mathematical model is established to calculate the force of magnetic field on the magnetic core. COMSOL is used to simulate the magnetic field distribution between the two coils, calculate the electromagnetic force of the magnetic core under different excitation current, and analyze the simulation data to get the linear characteristics of the electromagnetic force. The calibration experiment is built by using the precision electronic balance, and the calibration data is linearly fitted by the least square method. The coefficient of determination is 0.999,which has good linear characteristics. Compared with the simulation results, the effect is ideal, which lays the foundation for the subsequent micro thrust measurement.