SPACECRAFT PITCH AND ROLLIYAW ACTUATIONS USING CONTROL MOMENT GYROSCOPES FOR ATTITUDE STABILIZATION

This paper investigates the pitch and roll/yaw actuation using control moment gyroscopes (CMGs) fo r spacecraft, i.e., International Space Station (ISS). CMGs act as a control hardware for an active stabilization technique in order to keep the spacecraft attitude within a desired orientation at all time with a good pointing accuracy. In this regards, the critical aerodynamic disturbance torques acting on a spacecraft can be suppressed and without employ ing attitude thrusters. The analysis starts with a study ofthe spacecraft dynamics and behavior based on the Euler linearized equations ofmotion. Then, the imp lementation of the pitch and roll/yaw control architectures using those equations are carried out. Subsequently, the control algorithms are tested using the MATLAB® and Simulink®. It is shown that via tuning the control gain values, the pointing errors can be minimized. The responses of the attitude control obtained .from the fee dback system show that good pointing accuracies can be accomplished with dedicated attitude controllers.