Research on the electromagnetic de-tumbling of non-cooperative targets with nutational motion： theoretical and simulation study

To address the safety requirement of detumbling non-cooperative targets for on-orbit servicing and debris re⁃ moval, this paper investigates a non-contact electromagnetic detumbling method. In order to solve the problem of accu⁃ rately and quickly calculating electromagnetic torque on targets undergoing nutation motion, a mathematical model was established to describe the interaction between a magnetic dipole and a non-magnetized homogeneous conductive spheri⁃ cal shell in a symmetric magnetic field configuration. An approximate analytical expression for the electromagnetic torque acting on the spherical shell during nutation motion was derived. To further improve the model’s accuracy, finite element simulations were conducted to analyze the eddy current distribution on the shell surface and the electromagnetic torque values at different distances. A distance correction factor based on a power-law function was introduced to refine the theoretical analytical expression. The results show that the corrected torque analytical model closely matches the high-precision finite element simulation results, with errors controlled within 3%. Finally, based on the corrected model, the electromagnetic detumbling process was simulated and analyzed. The results indicate that under given pa⁃ rameters, the target’s total angular velocity can decay to zero within 12 600 seconds, and after 2 500 seconds of detum⁃ bling, its angular velocity can be reduced to the safe capture threshold for space robotic arms, approximately within 4～ 5 °/s. This study provides a reliable theoretical model and simulation foundation for implementing electromagnetic detumbling missions against non-cooperative targets exhibiting complex tumbling motion.