Performance and stability characteristics of risk sensitive controlled structures under seismic disturbances

This paper introduces the notion of risk-sensitive (RS) controllers for the protection of civil engineering structures from seismic disturbances. The risk-sensitive strategies are a generalization of linear-quadratic-Gaussian (LQG) controllers, and are stochastic cousins to counterparts based upon dynamic games and H_∞ methods. Even though much research is done in the area of risk-sensitive control theory, not much is known about risk-sensitive controller characteristics. In this paper a risk-sensitive acceleration feedback control for a multi-degree-of-freedom structure is investigated. Performance and relative stability comparisons are made between the risk-sensitive controller and a classical H₂/LQG controller. Moreover, by means of reliability analysis, it is shown that the risk-sensitive controller family can influence such performance features as probability of instability and stationary covariances of state variables and control actions-in the context of buildings with earthquake excitation and real parameter uncertainties described by probability distributions