ABSTRACT
Many basic concepts of linear control systems are also applicable to the sample-data and digital control systems; however, there are certain differences due to the very nature of the sampling process and digitization of the continuous time control systems. The continuous time algorithms for control systems/controllers/estimators can be converted in the discrete form so that their implementation on a digital computer is relatively easy; however, in most cases, it would be necessary to convert not only these algorithms, but also all the sub-systems into discrete time systems/algorithms. In a digital control system, the control and communication signals are generated by converting the continuous time signals into sequence/s of numbers at discrete time intervals. Continuous time systems and related formulas/algorithms can be converted into discrete time systems and corresponding formulas by using difference equations. The chapter considers the linear time-invariant systems. Mainly two approaches are used: backward difference and forward difference.
