Multiobjective optimal fuzzy logic controller driven active and hybrid control systems for seismically excited nonlinear buildings

Abstract

The third generation benchmark control problem for seismically excited nonlinear buildings 
is an effort to evaluate the developed control strategies in order to apply them in field 
applications. As the fuzzy logic control systems have been applied effectively in various 
fields, including vibration control of structures, a multiobjective optimal fuzzy logic control 
system has been proposed-in this paper. Two types of control devices, namely, active and 
hybrid, driven by a fuzzy logic controller (FLC) have been considered in the present study. 
Nondimensionalized peak interstory drift ratio and peak floor acceleration have been used 
as the two objective functions for the multiobjective optimal design problem. A two-branch 
tournament genetic algorithm has been used to find a set of Pareto-optimal solutions, as the 
optimization problem is not necessarily continuous of convex. Performance of the FLC driven 
active and hybrid control systems have been evaluated for all three third generation benchmark 
problems for seismically excited nonlinear buildings (3-, 9- and 20-story). Acceleration and 
velocity information of different floors have been used as feedback to the FLC. This approach 
provides a set of Pareto optimal designs, from which a controller design can be selected for 
the required performance. The FLC driven active control system performs better than the 
sample controller given in the benchmark problem. Though the number of sensors and 
control devices are far less, the performance of the hybrid is close to the active control 
system.