Modern technology allows implementation of high-performance controllers at a very low cost. Conversely, several analysis tools which were previously considered an inherent part of control system courses limit the design to low-order (and therefore low-performance) compensators. Among these are the root-locus method, the detection of right-sided polynomial roots using the Routh-Hurwitz criterion, and manual calculations using the Laplace and Fourier transforms. These methods have been rendered obsolete by computers and are granted only a brief treatment in the book, making room for loop shaping, Bode integrals, structural simulation of complex systems, multiloop systems, and nonlinear controllers, all of which are essential for good design practice.
Classical Feedback Control describes design and implementation of high-performance feedback controllers for engineering systems. The book emphasizes the frequency-domain approach which is widely used in practical engineering. It presents design methods for linear and nonlinear high-order controllers for single-input, single-output and multi-input, multi-output, analog and digital control systems.