Abstract
This paper deals with control schemes of relative motion between two spacecraft (chaser and target). Two cases are considered: 1) the case where relative 6 d. o. f. (degrees of freedom) are all controlled and 2) the case where relative LOS (Line Of Sight) angles are controlled. The basic idea of the control schemes is the input-output linearization. The control schemes are derived systematically by using the equations of motion about the controlled variables. In the relative 6 d. o. f. control, linear parameters are used to express the relative attitude of the chaser to the target. The relation between their time derivatives and the angular velocities of both spacecraft is derived. Based on this relation, we obtain the control scheme of the relative 6 d. o. f. control in a simple form. In the LOS angles control, we propose to control the LOS angles of the chaser to the target and the chaser attitude in the inertial space separately. This control law easily realizes the fly-around motion of the chaser to the target without sensing the inertial position of the chaser. Numerical simulations have been executed to verify the proposed control schemes.
