Patent ID: 6519582
Filing Date: 2003-02-11
Classification: G05D

Abstract:
Process for controlling at least two production units whose outputs are connected in parallel in order to produce a common output flow which is intended to feed a consumer plant, the process controlling the common output flow as a function of a predetermined target value (u), the process comprising the steps of:measuring at least one variable representing the common output flow; for each unit, determining a control instruction corresponding to one operating state of the unit among a finite set of predetermined operating states by the steps comprising: (a) comparing said at least one variable with at least one upper threshold and at least one lower threshold of said at least one variable; (b) determining a control instruction of activating said production unit if said at least one variable is less than said at least one lower threshold to control said at least two production units; (c) determining a control instruction of deactivating said production unit if said at least one variable is greater than said at least one upper threshold; and (d) if said at least one variable is not greater than said at least one upper threshold and is not lower than said at least one lower threshold, measuring a pressure (P) and a change in pressure over change in time (&Dgr;P/&Dgr;t) of said common output flow and determining the control instruction by a fuzzy-logic controller implementing the steps comprising (i) constructing input fuzzy variables on the basis of said pressure (P) and said change in pressure over change in time (&Dgr;P/&Dgr;t); and (ii) for at least one unit, on the basis of said input fuzzy variables and a knowledge base compiled beforehand and not depending on intrinsic characteristics of the production units, determining said control instruction corresponding to one of the operating states among the finite set of predetermined operating states; and applying the determined control instruction to control said at least two production units.