Observability and sensor positioning for processes described by linear-bilinear equations

The control of a process requires a minimum of representative information on its operating state. This information can be obtained by both direct sensors or indirectly using mathematical models. It frequently occurs that the number of direct measures is not sufficient to allow unmeasured variables to be deduced and additional sensors have to be installed to render the required variables observable. This paper presents a new technique to place sensors in systems described simultaneously by linear and bilinear equations. It takes into account placement constraints and a complete observability is obtained. Moreover, it is pointed out that from an observability point of view a bilinear system may be studied by considering a succession of linear systems.