ABSTRACT
This chapter describes the classical control design methods. In contrast to classical methods, modern control design methods can be characterized as analytical and are mostly developed in the time domain. The field of modern control engineering which is based upon the minimization of cost functions is called optimal control. Phase-lead controllers are used to introduce a positive phase in the closed-loop transfer function, aimed at improving the transition response of the system in the time domain and in the frequency domain at improving the gain and phase margins and the bandwidth. The design of a phase-lead controller is done preferably with the use of Bode diagrams, since the influence of the controller is calculated by simply adding the amplitude and phase diagrams of the controller to the corresponding diagrams of the given system. Let the design specifications refer only to the steady-state error and the gain and phase margins.
