Mixed H−/H∞ fault detection observer design for multi model systems via nonsmooth optimization approach

This paper deals with a fault detection observer design problem for multi models with only a unique observer, using the worst-case fault sensitivity measure, the H_- index, and the worst-case disturbance robustness measure, the H_∞ norm. The fault detection problem with the criteria of H_-/H_∞ can be formulated as a constrained optimization problem, which can be solved by using nonsmooth optimization method. By adding the constraint of the eigenvalues, the proposed method could improve the fast transients of the residual from the faults with the criteria of H_-/H_∞. The proposed method is shown to perform well on two examples: the nonsmooth optimization method will compare with other classical methods with a single model and design a unique observer for a vehicle lateral dynamics switched system with the trade-off between the optimal values of criteria H_-/H_∞ for different models.