Optimal Control of Tall Buildings by Appendages

Abstract

The active control of tall buildings by aerodynamic appendages was proposed with the purpose of minimizing the control energy used to generate the control forces. In this control mechanism, the appendages generate the control forces from the wind power, and the supplied control energy is only used for folding or deploying the appendages. A solution given in 1972 has made the appendage movement dependent only on the velocity of the vibrating building with respect to the mean wind direction. Another solution given in 1979 and 1981, which was more effective, was found by the optimal control theory, assuming the wind characteristics and the wind forces on the building are fully known. Based on this assumption, this paper shows that a tracking control can be developed which is superior to the previous solutions in both the controlled response and the consumed control energy. However, in practice, the difficulties encountered in the full knowledge of the wind characteristics and the wind forces overweigh the design given in 1972.