Reaction wheel control, testing and failure analysis for STUDSAT-2

This paper describes the attitude control approach of a nanosatellite in different scenarios of reaction wheel failure. The approach to allocate the control torques across the 4 wheels is explained considering the cases of one and two wheel failures. A Linear Quadratic Regulator is used to find the gains of the Proportional Derivative (PD) controller employed to determine the control torques to be generated by the reaction wheels in order to correct a specific attitude error and damp angular rates. The different analysis done in attempts to stabilize the satellite for all the aforesaid conditions has been presented. The paper also describes the electrical modeling of Brushless DC motor to get the transfer function and obtain P, I (Integral) and D parameters for optimum motor performance. ARM STM32F407 is used as the main microcontroller for the satellite. The operation flow of the implementation of control approach is explained. An account of different interfaces and peripheral used to realize control system design is described.