A new measure of process output controllability

A steady state, multivariable, and nonlinear measure is presented for asses sing the input-output, open-loop controllability of a process. This measure ascertains the inherent controllability of the process, as it is calculate d in the absence of any regulatory control structure. For the process examp les utilized in this paper, it is also independent of the inventory control structure that might be assumed present in or der to keep the inventory le vels constant. This measure evaluates the ability of a design to reach all points of the desired output space and to reject the expected disturbances utilizing input action not exceeding the available input space. Besides bei ng applicable to a SISO (Single Input, Signal Output) case, its multivariab le character is shown to be more appropriate than existing measures such as RGA (Relative Gain Array), minimum singular value, and condition number. ( C) 2000 IFAC. Published by Elsevier Science Ltd. All rights reserved.