Causal clipped semi-active control of earthquake response

The truly optimal semi-active control establishes the best possible performance of a dynamically excited and semi-actively controlled structure. While it can not be implemented in practice, it provides a performance goal for implementable control schemes. This paper proposes an implementable clipped semi-active control to suppress the earthquake response. The proposed method uses the minimax approach to modify the control parameter. The performance of a single degree of freedom (sdof) structure is investigated for the proposed control and compared to those of the optimal passive damping, the truly optimal control and the uncontrolled case. The results obtained illustrate that the proposed control outperforms the optimal passive damping control and the semi-active damping modified by the proposed control has a potential to adapt to the characteristics of the earthquake ground motion. It is also concluded that the semi-active damping has ability to follow the truly optimaltrajectories more closely with improved control methods.