1. A method for generating a control vector during each of a plurality of sampling instants k, said control vector to be applied to an apparatus which carries out a process having at least one input variable and at least one output variable, at least one of said input variables defining a process input vector, said apparatus varying said process input vector in accordance with the value of said control vector, said method comprising the steps of: (A) storing a model which is capable of predicting the dynamic value of a process output vector, which vector is composed of at least one of said process output variables, at a future sampling instant k+r+1 as a function of said control vector; (B) generating a desired dynamic process output vector at each of said sampling instants k, said desired dynamic process output vector being representative of a desired value of said process output vector at said future instant k+r+1; and (C) generating, at each of said sampling instants k, that control vector which said model predicts will cause said dynamic process output vector to be equal to said desired dynamic process output vector at said future sampling instant k+r+1.