Identification of time-varying system and energy-based optimization of adaptive control in seismically excited structure

The combination of structural health monitoring and vibration control is of great importance to provide components of smart structures. While synthetic algorithms have been proposed, adaptive control that is compatible with changing conditions still needs to be used, and time-varying systems are required to be simultaneously estimated with the application of adaptive control. In this research, the identification of structural time-varying dynamic characteristics and optimized simple adaptive control are integrated. First, reduced variations of physical parameters are estimated online using the multiple forgetting factor recursive least squares (MFRLS) method. Then, the energy from the structural vibration is simultaneously specified to optimize the control force with the identified parameters to be operational. Optimization is also performed based on the probability density function of the energy under the seismic excitation at any time. Finally, the optimal control force is obtained by the simple adaptive control (SAC) algorithm and energy coefficient. A numerical example and benchmark structure are employed to investigate the efficiency of the proposed approach. The simulation results revealed the effectiveness of the integrated online identification and optimal adaptive control in systems.