Multi-level optimal design of buildings with active control under winds using genetic algorithms

The goal of this paper is to study the complicated optimal design problem o f integrating the number of actuators, the configuration of the actuators a nd the active control algorithms in buildings excited by strong wind force. To do this, the following sequential studies are carried out: (1) Two cont rol algorithms, linear quadratic regulator (LQR) and acceleration feedback control algorithm, are analyzed and used as the control algorithms. (2) The characteristics of the optimal design problem are analyzed in detail by a simulation study. (3) A multi-level optimization model is proposed, and the formulation of sub-optimization problems in each level is presented. (4) T o solve the multi-level optimization problem, a multi-level genetic algorit hm (MLGA) is proposed. The properties and implementation of MLGA are given and analyzed in detail. Finally, the optimal design model and the correspon ding solving algorithm are tested by numerical simulation. The results show that: (1) in the design of actively controlled structures subjected to str ong wind excitation, the problem of considering the number of actuators, th e position of actuators and the control algorithm simultaneously is of a mu lti-level design optimization with the properties of non-linearity, discret eness and so an. (2) This kind of optimization problem should be described naturally by the multi-level design model. (3) The multi-level genetic algo rithm can solve this complicated problem effectively. (4) The optimal locat ions of actuators depend on the control approaches. (C) 2000 Elsevier Scien ce Ltd. All rights reserved.