Closed-loop transfer function
A closed-loop transfer function in control theory is a mathematical expression (algorithm) describing the net result of the effects of a closed (feedback) loop on the input signal to the plant under control.
The closed-loop transfer function is measured at the output. The output signal can be calculated from the closed-loop transfer function and the input signal. Signals may be waveforms, images, or other types of data streams.
An example of a closed-loop transfer function is shown below:
The summing node and the G(s) and H(s) blocks can all be combined into one block, which would have the following transfer function:
We define an intermediate signal Z (also known as error signal) shown as follows:
Using this figure we write:
Now, plug the second equation into the first to eliminate Z(s):
Move all the terms with Y(s) to the left hand side, and keep the term with X(s) on the right hand side:
- Federal Standard 1037C
- Open-loop controller
- Open-Loop Transfer Function