6. Optimum control

6.1 Presentation

The problem of optimal control consists in finding the optimum value of the parameters of a controller whose structure is fixed in advance. The main advantage of this practice lies in imposing constraints on the shape of the controller and the number of control coefficients, e.g. a series PID with an imposed ratio between integration and derivation time constants.

Unlike previous techniques, where the feedback control structure was revealed a posteriori, the control structure will be imposed a priori.

Optimization criteria generally relate to a deviation variable e (t ) that tends asymptotically towards 0, and can take one of the forms described in Table 2 ....