Transfer-function formulation of analysis and design problems for discrete/continuous control theory

This thesis is an investigation of Discrete/Continuous (D/C) analysis and control design problems, using conventional discrete-time transfer-function block-diagram methods. The relatively new idea of Discrete/Continuous Control, introduced in 1994 by C. D. Johnson can be viewed as a broad generalization of classical ZOH-Type discrete-time control which is currently used in virtually every application of discrete-time or digital control. D/C control allows the control input to continuously vary in time between each consecutive sampling-times, t = kT and t = (k + 1)T, as opposed to ZOH-type control where the control input is always held constant between consecutive sampling-times.; This investigation is concerned with the application of conventional discrete-time transfer-function methods to the formulation and solution of D/C analysis and control design problems, using conventional block-diagram techniques. In the case of time-invariant, MIMO, D/C controlled systems, it is shown that general-expressions can be developed that allow “D/C compensator” design and closed-loop transfer-function evaluation by using classical transfer-function methods without using state-variables, state-observers, etc.; The effectiveness and simplicity of the transfer-function formulation of D/C control analysis and design problems make this method an attractive alternative to modern state-variable methods.