Optimal control and scheduling of networked control systems

This paper addresses optimal control and scheduling of networked control systems (NCSs) where controllers and actuators are connected via a shared communication medium. The NCS is modeled as a discrete-time switched linear system. The control and scheduling strategy are then optimized jointly. Therefor, a receding-horizon control and scheduling (RHCS) problem with a quadratic performance criterion is formulated and solved by (relaxed) dynamic programming. The resulting RHCS strategy can be expressed explicitly as a piecewise linear state feedback control law defined over regions implied by quadratic forms. Closed-loop stability is not guaranteed inherently for the RHCS design. Therefore, an a posteriori stability criterion based on piecewise quadratic Lyapunov functions is given. The effectiveness of the RHCS strategy is evaluated for networked control of an active suspension system.