Paul W. Murrill

An optimal controller for multivariable systems subject to disturbance inputs

Abstract : Most industrial processes have two features in common: (1) they are multivariate in nature and (2) they are subject to unmeasured disturbances for which control systems must be installed. The conventional design of multivariable systems has been considered by Bollinger and Lamb, Dahlin et. al and Shinskey. Douglas considered the constrained optimal control of multivariable systems, deriving the optimal switching curves for a representative system. This objective of this work is to present a design technique for linear, continuous controllers for multivariable process systems. The method will use the concepts for the optimal control of linear systems as presented by Athans and Falb. The conventional disturbance control problem is reformulated in a manner that allows optimal control theory to be used directly. (Author)

Criteria for evaluating Fourier transform computational results

Abstract : When numerical methods are used to calculate Fourier transforms from discrete points from the input and output of a dynamic system, the resulting Bode plot degenerates at high frequencies. Several factors contribute to this, e.g., foldover, noise in data, computational methods, etc. To effectively analyze the effect of these, it is essential that the blow-up point be determined accurately and consistently. This paper examines integral criteria for this purpose. (Author)