ABSTRACT
The sensor, control device and processor that are described, respectively, in Chapters 3 through 5 can be viewed as hardware devices for the establishment of an entire control system, whereas the control algorithms introduced in Chapter 9 can be viewed to some extent as software for the realisation of the optimal control of civil structures. To enhance control performance, one can target the improvement of the quality of hardware devices and develop more efficient and reasonable control algorithms. Nevertheless, with the given hardware and software, control effectiveness will strongly depend on the locations of control devices in the structure, because it is impractical and uneconomical to install control devices in all the possible locations of a large-scale civil structure. Therefore, it is highly desirable to investigate control device placement in a civil structure for the purpose of improving control efficiency and cost. A control device is defined in this book as a type of device that is responsible for moving or controlling a civil structure, including not only the actuator operated by a source of energy, but also the damper operated without external energy. This chapter first reviews some existing control device placement methods for passive control systems, active control systems, semi-active control systems and hybrid control systems. Then, by taking the linear quadratic performance index as an objective function, an increment-based algorithm is presented in this chapter for the optimal placement of active/passive control devices in terms of the sequence of the calculated performance index increments and the number of control devices to be used. With the control devices in their optimal places, the seismic response of the building is computed using the suboptimal control gain derived on the basis of the minimum error principle, from which the equivalent optimal parameters of passive devices can also be determined.
