Interpolating Constrained Control of Interconnected Systems

Abstract

This paper presents a decentralised interpolating control scheme for the control of linear discrete-time interconnected systems with local state and control constraints. The control law of each distinct subsystem relies on the gentle interpolation between a local high-gain controller, which satisfies some user-desired performance specifications, with a global low-gain controller. For each subsystem both low- and high-gain controllers can be efficiently determined off-line, while the inexpensive interpolation between them is performed on-line. For the interpolation, a new low-dimensional linear programming formulation is developed, which is computationally less expensive compared to previous works. Therefore, it is appropriate for realtime control of large-scale interconnected systems. Proofs of recursive feasibility and asymptotic stability of the interpolating scheme are given for decoupled as well as interconnected subsystems with coupled state constraints. Two numerical examples show that the proposed decentralised interpolating control outperforms previously proposed interpolating schemes. Finally, it is faster than model predictive control, while their control behaviour and performance is almost identical.