Satellite attitude stabilization using fluid rings

The three-dimensional attitude stabilization of a satellite using fluid rings is proposed in the present paper. The general formulation of the system that comprises a satellite and three fluid rings, one on each axis, is obtained through Euler’s moment equations. The linearized system model is derived and the stability conditions are obtained. Linear control laws and nonlinear control laws based on sliding mode control techniques are developed for fluid control torques. The numerical simulation of the governing nonlinear equations of motion of the system along with stability analysis establishes the feasibility of achieving desired attitude stabilization of the satellite. The fluid controllers are successful in stabilizing the attitude of the satellite in presence of high attitude disturbance torques and intermittent actuators’ failures. In the case of sudden attitude disturbance torques, the nonlinear fluid controllers outperform the linear fluid controllers with virtually no effect on the satellite attitude response. The proposed attitude stabilization method may find applications in future satellite missions.