William A. Wolovich

Invariants and Canonical Forms under Dynamic Compensation

This paper is concerned with the development of a complete abstract invariant as well as a set of canonical forms under dynamic compensation for linear systems characterized by proper, rational transfer matrices. More specifically, it is shown that one can always associate with any proper rational transfer matrix,

A parameter adaptive control structure for linear multivariable systems

T(s)

Paper: Parameterization issues in multivariable adaptive control

, a special lower left triangular matrix,

On the stability of solutions to minimal and nonminimal design problems

\xi _T (s)

Output feedback decoupling

, called the interactor. This matrix is then shown to represent an abstract invariant under dynamic compensation which, together with the rank of

On determining the zeros of state-space systems

T(s)

The determination of implicit polynomial canonical curves

, represents a complete abstract invariant. A set of canonical forms under dynamic compensation is also developed along with appropriate dynamic compensation.

Deadbeat error control of discrete multivariable systemsdagger

This paper presents an adaptive control structure which can be used to assign all poles and zeros of a continuous-time linear multivariable system represented by an ( m \times m ) strictly proper transfer matrix T(s) , provided T(s) has no right-half plane zeros. The controller parameters can be directly estimated from input-output data. The paper also serves to point out the type of a priori information necessary for multivariable adaptive controller design. This information is a natural extension of that required in the scalar case.

Paper: A frequency domain model reduction procedure

This paper gives both an overview of multivariable adaptive control algorithms which have evolved to date and presents some new approaches to the design of indirect multivariable adaptive control systems. All algorithms are presented using a unified pole placement approach. Furthermore the emphasis is on parameterization issues such as: types of control structures necessary for implementation, required prior information necessary for implementation and techniques for reducing the size of the resulting parameter estimation problem.

Bumpless switching controllers

A partial resolution to the question of stability of solutions to the minimal design problem is given in terms of transfer matrix factorizations employing the new notions of common system poles and common systems zeros as well as the fixed poles of all solutions and the fixed poles of minimal solutions. The results are employed to more directly and easily resolve questions involving the attainment of stable solutions to the model matching problem and stable minimal-order state observers.