OBSERVATION OF QUALITATIVE STATES BY MEANS OF A QUALITATIVE MODEL

This paper is concerned with the problem of reconstructing the qualita tive values of the system states from quantized measurements of input and output sequences by means of a qualitative model. It is assumed th at the state, input and output spaces are partitioned into disjoint re gions. The numbers of the regions are used as qualitative values of th e corresponding signals. The proposed observer uses a qualitative mode l of the continuous-variable discrete-time system. The model has the f orm of a non-deterministic automaton. A necessary and sufficient condi tion is given under which the observer generates a set of qualitative states that includes the qualitative state of the real system. The ben efits of the observer for process supervision are shown by applying it to a tank system.