Fault diagnosis and fault-tolerant control allocation for a class of nonlinear systems with redundant inputs

The problem of fault-tolerant control allocation for a class of overactuated nonlinear systems is considered. The construction extends to the nonlinear case some results obtained previously in the linear systems framework. The proposed scheme consists of three main steps: fault detection/approximation using a nonlinear observer, fault isolation through a bank of unknown input observers with a resetting policy to reduce the effects of nonlinearities and control reconfiguration based on reduced order allocation.