On fault tolerant control structures incorporating fault estimation

The paper provides the minimal necessary modifications of linear matrix inequality conditions for the mixed H2/H∞ control design as well as for the augmented observer-based fault estimation to be mutually compatible in joint design of integrated fault estimation and fault tolerant control. To be possible, within this integration, to design the controller which guarantees a pre-specified H∞ norm disturbance attenuation level, the design conditions has to be regularized using the H₂ performance index and, moreover, augmented fault observer must be of enforced dynamics. Analyzing the ambit of performances given on the mixed H₂/H∞ design, the joint design conditions are formulated as a minimization problem subject to convex constraints expressed by a system of LMIs. The feasibility of the conditions is demonstrated by a numerical example.