Research on Effect Factors of Millinewton Electromagnetic Force for Calibrating Force Source

Abstract

It’s an important guarantee for calibrating the thrust measuring device of micro thruster to have stable and controllable millinewton force. In this paper, a device generating millinewton force is designed based on current magnetic effect and mutual conversion principle between magnetic field energy and electromagnetic force. According to electrical theory and magnetic theory, the theoretical mathematical models about electromagnetic force over current and electromagnetic force over air gap are established, respectively. When the air gap between electromagnetic coil and magnetic block is 9mm and current ranges from 0mA to 163mA, the material of magnetic block is 2Gr13 and 45 carbon steel, the generated electromagnetic force is 0-34.83mN and 0-34.82mN, respectively, whose nonlinearity and repeatability error are less than 1%. Aiming at two materials of magnetic blocks being 2Gr13 and 45 carbon steel, the generated force values are 1.53-31.81 mN and 1.48-31.35mN when the air gap changes from 17mm to 7mm and the current keeps 110mA, respectively, whose nonlinearity are less than 5% and the repeatability error are less than 1%. The results show that the main influence factors of electromagnetic force are current and air gap, and material has a less influence on electromagnetic force.