Electromagnetic Calculation And Optimal Design Of A Reaction Sphere For Micro-satellite Attitude Control

With the application of the micro-spacecraft gradually expanded,momentum actuator,the key component of the attitude control system of the microsatellite,gains more and more attention.Compared to reaction wheels and control moment gyroscopes,three-degree attitude adjustment of the micro-spacecraft can be realized by a single reaction sphere due to its ability to output three-axis torque,which reduces the volume and mass of the attitude control systems.Based on a magnetic levitation induction reaction sphere for micro-satellite attitude control,this paper mainly focuses on the optimized design of the winding design and the parameter calculation of the equivalent circuit.First,the topology structure of a magnetic induction reaction sphere is introduced,and the main working principle is amplified.Magnetic suspension bearing is used to reduce the frictional resistance during rotating,and three stators with the same structure and orthogonal to each other are used to simply analysis and control.The hollow steel sphere coated with copper layer is used as the rotor to reduce the high-order harmonics of the electromagnetic field.Then the analysis of the winding arrangement based on the special structure of the stator core is carried,and finite element analysis is used for assistant analysis.Under the goal of improving the torque and speed,the influence of windings parameters on the motor is discussed and the optimized winding design scheme is established.Next,the equivalent circuit of the reaction sphere is established and transfermatrix method is used for the parameter calculation.Finite element method is used for the verification,so the relationship of the electromagnet parameters and the mechanical parameters is clear and the operating status can be predicted.Finally,ground test system of single axis reaction sphere is established and is used to verify the optimized winding design scheme and parameter calculation.The results verified the superiority of the optimized winding design scheme.But there is a numerical gap between the results of the experiment and analytical calculation of the equivalent circuit due to machining and assembly errors.