Time-Delay Effect on Dynamic Response of Actively Controlled Structures

The effect of time‐delayed control signals on the stability and the dynamic response of actively controlled structures is investigated. The necessary optimal control law that takes the effect into account is derived using the variational approach. With the help of an example of a moment‐controlled simply supported beam subjected to a concentrated load, it is shown how time delay cannot only degrade the system response, but can also destabilize actively controlled structures. A gain‐compensating technique is proposed, and its use is illustrated with the help of the example. The results indicate that the effect of smaller values of time delay can be compensated for by applying additional energy, but the effects of higher values may not be compensated for, because of the prohibitively larger amounts of energy required in those situations.