Q2Control System
Question
Q.2. Differentiate closed loop and open loop control system.
Answer
A closed loop (feedback) control system measures its output and feeds it back to compare with the reference, correcting error automatically; an open loop system has no feedback path and its output does not influence the control action.
An open-loop control system generates its output purely as a function of the given input and a predetermined control action, with no path to measure the actual output and feed it back for comparison; hence it cannot correct for disturbances or parameter drift (e.g. a simple washing machine timer). A closed-loop control system, by contrast, continuously measures the output via a sensor and feeds it back to be compared with the reference input, generating an error signal that drives the controller; this makes closed-loop systems self-correcting, more accurate, and less sensitive to disturbances and parameter variations, but at the cost of added complexity and the possibility of instability if not properly designed.