'Feedback' and 'feedforward' conditioning techniques

It is generally admitted that the classical conditioning technique is restr icted to some application conditions like the bi-property of the controller and its inverse stability. Some extensions to overcome these restrictions are recalled in the paper. The conditioning technique has been conceived an d must always be considered as an a posteriori anti-windup method (the a pr iori knowledge of the non-linearity acting on the desired control variable has not to be known, provided a postmeasurement of the actual control varia ble is available). Hence, this kind of "feedback" anti-windup should always be used because it is never possible to prejudge of any non-linearity that could appear. However, when an a priori knowledge of some non-linearities is available, it is possible to include this knowledge either in the synthe sis of the controller or in the design of a "feedforward" anti-windup. Two methods of feedforward anti-windup are given in the paper, namely, the opti mal conditioning and the predictive conditioning techniques. We propose to keep the term conditioning for these last anti-windup schemes, because as i n the classical conditioning technique, we try to "condition" the controlle r to be able to carry on, as soon as possible, in the same way as in the li near case.