Читать книгу Control Theory Applications for Dynamic Production Systems - Neil A. Duffie - Страница 17

Variables in continuous-time models have a value at all instants in time. Many physical variables in production systems are continuous variables even though they may change abruptly. Examples include work in progress (WIP), lead time, demand, and rush orders. Continuous-time modeling results in differential and algebraic equations that describe input–output relationships at all instants in time t. Although the specific output function of time that results from a specific input function of time often is of interest, the goal is to obtain models that are valid for any input function of time or at least a broad range of input functions of time because the operating conditions for production systems and their components can be varying and unpredictable.