In such systems, the relative stability is a significant parameter. The relative stability is the measure of how close the system is to instability. It is usually defined using gain margin and phase margin. Consider that a unity feedback system is defined by the open-loop transfer function shown in equation (10). I'm thinking about a mathematical possibility how an open loop system can replace a close loop system so here is my explanation Let's say I have a plant with transfer function as given in image (1) But to achieve a desired output with minimum effect of disturbances ,I Make it a close loop with unity feedback and it works very well (image 2) Then an Open-loop system, also referred to as non-feedback system, is a type of continuous control system in which the output has no influence or effect on the control action of the input signal. In other words, in an open-loop control system the output is neither measured nor “fed back” for comparison with the input. contoh untuk sistem kendali kalang tertutup sangat banyak didunia nyata bahkan kehidupan manusia pun termasuk dalam sistem kendali kalang tertutup. seperti Alat penetas telur, dari alat ini hasil output berupa suhu dalam derajat, katakanlah awalnya kita memberikan Set point suhunya 20 derajat Celcius, jika kita hanya menggunakan Sistem kendali In racing, closed loop should not be considered a long-term tuning tool, and ideally, we want only a maximum deviation of 1 to 2 percent between target and actual O2 readings during wide open throttle. The primary reason for this low maximum is that closed-loop control is a reactive process and relatively slow. xT0I.

close loop dan open loop