Digital redesign of a nonlinear state-feedback control system based on the Principle of Equivalent Areas

The present study is concerned with the digital redesign of an analog, nonlinear, state-feedback control system, such that the time-integrals of the analog and digital control inputs are approximately equal in the sense of the Principle of Equivalent Areas. Although stability is not guaranteed theoretically, simulation studies show that this approach yields better digital controllers than the traditional emulation method, where analog control gains are used and samplers and hold elements are simply inserted. Furthermore, the proposed method is simpler and generally has closer results to analog original, than a recently proposed method based on the Lyapunov method.