Attitude and position control for under actuated satellite by ON/OFF thrusters

This study proposes a new control method for under-actuated planar satellites having body-fixed thrusters that can generate unilateral and constant forces. The proposed method is applicable when the thrusters are not balanced, which means a rotational motion is inevitably induced whenever the thrusters are turned on. By applying the method, the position and attitude of any planar satellite can be controlled to arbitrary target states so long as a controllability condition is satisfied. The control logic is based on a switching control using plural manifolds. First, the satellite is transferred to an initial manifold, and then it moves to another manifold while decreasing its velocity and approaching the target states. The ON/OFF timing of the thrusters to transfer among the manifolds is explicitly specified in this paper. A numerical simulation validates the proposed control logic.