On the Control of Satellites with Sun-Tracking Solar Array and its Drive System

Compared to the spacecraft with fixed flexible appendages, spacecraft which carrying movable flexible appendages and their drive systems are much more complicated in terms of dynamic modeling and system control. This paper is concerned with the satellite with a single flexible sun-tracking solar array and its drive assembly and introduces the dynamic models of the satellite attitude motion and the drive system of the appendage respectively. Based on the identity relationships between coupling matrices of the attitude dynamics, a generalized state space form of the spacecraft with a rotating flexible appendage is developed. In the framework of the passivity theory of descriptor systems, passivity of the electro-mechanical system is discussed, then a Lyapunov function is constructed based on the system storage function. L-2-gain of the output feedback based PD control against the friction and harmonic disturbance inside the drive assembly is studied. Theoretical results are verified by the computer simulations. Finally, concluding remarks and some possible topics are proposed.