STRUCTURAL STOCHASTIC OPTIMAL CONTROLS WITH OPTIMAL CONTROLLER TOPOLOGY

A concept of generalized optimal control policy for structural stochastic optimal controls is proposed in this paper that extends the classical forms of stochastic optimal control policies of passively controlled modalities, actively controlled modalities, semi-actively controlled modalities and hybridly controlled modalities. The proposed unified scheme features the simultaneous consideration of optimal control force and optimal device placement. A new controllability index related to the exceedance probability is developed which characterizes system safety (the controlled inter-story drift), system serviceability (the controlled inter-story velocity), system comfort (the controlled story acceleration), controller workability (the constrained control force) and their trade-off. The sequential procedure with a minimum story controllability index gradient is defined to efficiently search for the optimal controller topology. Further, a performance function of control parameters optimized is considered, which has the same physical meaning as the controllability index. The resolution procedure of the generalized optimal control policy is detailed, and a numerical example is investigated involving an eight-story shear frame controlled by active tendons. Numerical results reveal that the introduced generalized optimal control policy can achieve the maximum control effectiveness with the minimum control cost. We observe that the controlled system response is smoother along the height of the structure, resulting in a more desirable structural performance.