Optimal control of a tetrahedral configured reaction wheels for Quaternion rotation based on rigid satellite model

Abstract

Reaction wheel is the most popular actuator for the attitude manoeuvring of a satellite system due to its compact size, reliability and able to produce precise torque. However, for redundancy purposes, the reaction wheels are assembled in a tetrahedral configuration that is able to generate torque in any direction even when one of the reaction wheel fails. The tetrahedral configured reaction wheel causes the maximum torque generation to be uneven in any direction. Hence, the quaternion rotation is completed at different rate in different direction. In order to optimize the rotation rate, an optimal control using iterative method via GPOPS toolbox. It is then compared with the traditional Eigen-axis Quaternion Feedback control. The improvement shown by the optimal control to be between 3.49% to 25.11% improvement in manoeuvre time depending on the direction of manoeuvre. The optimal control is able to outperform the traditional control method.