assessment of the conventional control algorithms and proposing a modified displacement feedback control for performance-based design of structures

an enhanced displacement feedback structural control procedure is presented for performance-based design in this paper. at first, a comparative study is implemented assessing three most common active control algorithms including state, acceleration, and displacement feedback controls. the advantage of the displacement feedback algorithm for active control of structures against earthquakes is demonstrated through a number of representative examples. second, the conventional displacement feedback control is modified to keep the lateral displacements under a preset value and to apply the control forces only when needed not continuously, hence to minimize the input energy. the lateral displacement at a certain level, e.g., the roof, is used as an on/off switch for the applied control forces. when the target displacement is going to be exceeded, the control forces are applied to reduce the displacements. as a result, it is shown that use of the proposed algorithm considerably reduces the energy demand of the control system compared to other procedures. moreover, response of structure is controlled to any desired limit.