Steady-state closed-loop structural interaction analysis

Abstract

The steady-state closed-loop structural interaction array (SIA) is introduced to define a new measure of control loop interaction in multivariable control systems. The SIA is formulated from a signal flow graph representation of the system which is derived from a state-space model, explicitly revealing the interdependence of the variables describing the process. It is shown that systems with the same apparent input-output behaviour can have very different interaction properties. By using the SIA in conjunction with the Bristol relative gain array, insight is gained into the dynamic properties of the system from steady-state information.