Control of Time Delay Systems:Brief Review

Time delays are present in the system dynamics either due inherently in system model or may enter as a direct consequence of the finite capabilities of information processing and data transmission among various parts of the system. They may arise from inherent physical phenomenon like mass transport flow or transmission network either in observation or control loop. Further, they may be introduced intentionally due to certain design considerations. Systems incorporating delays in system model or in the control loops are known as Time Delay Systems. In such systems, the rate of change of several physical variables not only depends upon the current state but also depends upon the past history or delayed information. This paper presents review of different control strategies for the delay systems.