Decentralized Control of Third Generation Spacecraft

The decentralized control of a large flexible space structure (LFSS) as modelled by the MSAT configuration is considered in this paper. In this problem, the MSAT vehicle is highly unsymmetric and highly flexible with non-collocated sensors/actuators, and so the problem of effective controller design is quite challenging. In particular, it is desired to find a decentralized controller, based on a design model of MSAT, which solves the following problems, when applied to an unspecified evaluation model of MSAT: Attitude control - regulate the orientation of MSAT (3 outputs). Shape control - regulate the horn/reflector relative positions (6 outputs) in the presence of unknown constant/sinusoidal disturbances. Stability - stabilize rigid body and elastic body modes of the system. Robust behaviour - controller should not cause any undesirable "spillover effects" to occur. The paper gives a summary of results obtained in designing a decentralized controller to solve the above problem, together with some representative output simulations. A comparison of results obtained by using centralized control is also included, which shows that the decentralized design is highly effective compared to the centralized case.