Inverse dynamics: A problem on transient controllability for industrial plants

Abstract

Optimal performance of controlled industrial processes depends upon the dynamic response of the inverse of plant, known as zero dynamics; therefore it is necessary to follow inverse's dynamics in order to ensure controllability and resilience. Additionally, closed-loop dynamic behaviour depends upon several factors; one of the least studied is the choosing and pairing of control and manipulated variables. Although there have been several attempts to develop systematic evaluation of control schemes, intrinsic non-linearities and disturbances of this kind of systems provoke the behaviour of the inverse dynamics of the process to be difficult to predict. In this article, a simple strategy for the characterization of the inverse of the process dynamics is developed for control affine non-inear systems, taking for example, a biochemical reactor. The strategy proposed is easy to understand and to apply for the analysis of control schemes; furthermore it is independent of the type of controller used. Simulation results are used to illustrate the application of the methodology suggested.