**Control Time Shifts**

**08/22/17**

*“Can we have built-in time delays into control systems?”*

When working with control systems, sometimes we don’t want all actions to occur instantaneously. For example, we might want to have an elevator door wait to close a few seconds after everyone has entered. This can be modeled as a **time shift **within the system. A time shift for a function in the time domain can be represented by f(t) = x(t-tau) where tau is the time constant and in the Laplace domain by the equation f(s) = e^(-tau*s) *X(s).