Position and attitude control of a spacecraft using the state-dependent Riccati equation technique

Spacecraft which are required to remove space debris or collect disabled satellites must be able to achieve the attitude of the target while being positioned at a desired distance from the target. The six degree of freedom motion of a spacecraft performing rotational and translational maneuvers has nonlinear equations of motion. The state-dependent Riccati equation method of nonlinear regulation is used to control the position and attitude of a spacecraft in the proximity of a tumbling target. A six degree of freedom simulation of the spacecraft and target are utilized to demonstrate the effectiveness of the controller.