Stability of steady-state optimising control systems

The concept of composite dynamic and steady-state optimising control systems is introduced to characterise the behaviour of optimising control systems operating on transient process measurements. Stability issues for such systems are studied and emphasis is given to the impact of transient operations on the convergence of the optimising control algorithm. Sufficient conditions for the convergence of optimising control algorithms operating on transient measurements are derived for cases where the controlled process is linear and it is concluded that, under the normal assumptions for the convergence of pure steady-state operation, such systems are stabilisable. The effect of transient operation on the iterative gain region is examined for linear quadratic cases, showing that in many cases the stability of the system is improved.