A comparative analysis of cascade and feedback compensation

This thesis presents a comprehensive analysis and comparison of the relative effects of cascade and feedback compensation upon the steady-state and dynamic performance of feedback control systems. In particular, system sensitivity, steady-state system error and actuating signal, log-modulus response, and pole-zero considerations are investigated for cascade compensation and various forms of feedback compensation. Equations relating equivalent feedback and cascade compensators for a given uncompensated plant and an overall system transfer function are developed. Conditions are specified for the realizability of feedback compensators as R-C networks. Specific advantages and limitations of the various modes of compensation are noted and general insight is provided into the relative suitability of cascade and feedback compensation for a given system and set of performance specifications.