Effect of Time Delay on Control of Seismic‐Excited Buildings

Abstract

The sensitivity of a system time delay with respect to the performance of control systems for seismic‐excited buildings is examined. The effect of a system time delay depends on the particular control algorithm and the particular control system used. Four control algorithms feasible for applications to conttrol of seismic‐excited buildings have been studied. These include the linear quadratic optimal control algorithm and three instantaneous optimal algorithms proposed recently. The sensitivity analysis for each control algorithm is performed using a simulation approach. Both the active tendon control system and the active mass damper have been considered, and the tall building is idealized by a shear‐beam lumped‐mass discrete system. Numerical examples are worked out to demonstrate the criticality and tolerance of a system time delay for each control system. It is shown that a time delay always results in a degradation for the efficiency of a control system and that the tolerance for a system time delay is quite stringent for cases investigated.