Electromagnetic formation flights(EMFFs) can be stabilized in low Earth orbit owing to the influence of Earth's magnetic field.Formation control is realized by changing the current magnitude of the magnetic pole of the EMFF.Although Earth's magnetic field is generally considered to be a dipole and rotates with Earth,the interaction between the magnetic fields of Earth and the EMFF is considered to be an internal force.When a small magnetic satellite formation encounters an obstacle that must be avoided,the current magnetic force,which acts as an internal force,cannot promote directional changes.Therefore,it is necessary to exert external forces on the EMFF to gain control.As a continuation of the application of electric propulsion (EP) to Coulomb satellite formation,this study investigates how EP may be applied to collision avoidance by EMFFs.During the process,the external thrust of the EMFF was provided by EP,which served as supplementary propulsion to realize obstacle avoidance.EP adopted multimode Hall thrusters,and a linear formation was employed by the EMFF.Using the linear quadratic regulator control method with an added fuzzy reference system,EMFF achieved collision avoidance with numerical simulation.