As I said in the previous post Open loop control system dont give the required level of control as they depend on human judgement.
Example of feedback prnciple:
Home furnace control system must control the temperature in the room and kept it constant. As in open loop system a timer is used to switch on the furnace for some time and then switch it off, accuracy is not obtained. This is because the system doesot act according to the room temperature but according to a preset value of time.
Hence it is clear that a system with feedback (closed loop control system) is efficient than that of a system without feedback (open loop control system).
While designing a closed loop system, a compromise between stability and accuracy is to be astablished. This is because the gain of the system may exceed over a limit which may cause the system to be over correct, leading the system to become unstable, that is, oscillation of the output without bound.