ISSUES IN FREQUENCY DOMAIN FEEDBACK CONTROL THEORY (ROBUSTNESS, SENSITIVITY, SYSTEMS, MULTI-VARIABLE)

The purpose of this thesis is to examine several issues in the frequency domain theory of feedback control systems. Properties of both single loop and multiple loop systems are considered. For single loop systems the limitations on feedback properties imposed by right half plane poles and zeros of the plant are considered. The relation between open and closed loop properties of multiple loop systems is studied. A great deal of attention is given to how complex analyticity of matrix transfer functions limits feedback properties of multiple loop systems. An integral constraint generalizing Bode's gain-phase relation is presented.