ABSTRACT
The conventional techniques for design of continuous-time control systems have been well developed. These techniques are built around the Laplace transform representation of the differential equations describing the system dynamics. The analysis for closed-loop stability can be accomplished by examining the location of the closed-loop characteristic roots in the complex s-plane by the Routh-Hurwitz criterion. The analog-to-digital converter is the device that allows the computer to obtain the measured data about the system state. The digital-to-analog converter is the device that converts the numerical content of some register of the digital processor to an analog voltage and holds that voltage constant until the content of the register is updated, and then the output of the digital-to-analog converter is updated and held again. In a large number of physical control systems, the plant to be controlled by the digital computer is one that is described by ordinary differential equations.
