Influence of electromagnetic stiffness on coupled micro vibrations generated by solar array drive assembly

This work analyzes the influence of electromagnetic stiffness on coupled micro disturbance behavior of 32 and 64 subdivisions (SD) Solar Array Drive Assembly (SADA). The problem geometry consists of SADA supporting and operating rigid load through transmission shaft. Mathematical model of stepper motor, used as SADA, with two phases and four beats is developed to determine output excitation torque and electromagnetic stiffness. Keeping in view the reduction ratio, number of rotor teeth, beats and subdivisions; active and dead load SADA vibration model is developed. Rigid load operated by SADA is approximated into motor torsional spring moment of inertia dynamic system to obtain frequency response of mechanical configuration. The developed mathematical model contains information about moment of inertia of load, stiffness of electromagnetic spring, stiffness of transmission shaft and moment of inertia of SADA rotor. Results obtained from analytical calculations are validated by experimentation and simulations run in Matlab/Simulink. Analysis reveals that increase of electromagnetic stiffness, subdivisions number and rotor teeth leads to increase in stability of SADA operated system. The research lays a firm basis for study on vibration attenuation and analysis of SADA disturbances during in orbit operations.