Time delays are common in a variety of systems, often caused by communication lags, material transport, delayed sensing, etc. Time delays can cause instabilities and are generally harder to control unless compensated for.
Mathematica makes it easy to model and simulate delay systems by using a delay operator for either transfer function or state-space models. By either approximating delays or compensating for them, the full suite of design tools can be used for delay control systems.
SystemsModelDelay — represents a time-delay operator
StateSpaceModel — state-space model with delays
TransferFunctionModel — transfer-function model with delays
SystemsModelDelayApproximate — higher-order, delay-free system approximation
SmithDelayCompensator — compensates for internal delays in the system