Controller reconfiguration for nonlinear systems using composite observer

This paper addresses the issues of fault estimation and controller design for nonlinear systems in the event of actuator failures. The reconfigurable controller is designed based on nonlinear output regulation. It is shown how a composite observer, to estimate both the faults and the states, can be elegantly constructed using Lie transforms. Thus, the reconfigured regulator achieves the desired regulation based on the information about the states and failed actuators that is reconstructed by the composite observer.