Nonlinear Modeling for Fault‐tolerant Control

As already remarked, model–based and data–driven FDI strategies have been studied for over 40 years, however they still represent an open research domain when considered to be applied to dynamic processes, and many problems are waiting to be solved. The material presented in this monograph has inevitably had to end before all the interesting topics for future FDI research could be fully explored. In the following sections the authors describe some important topics that should help the reader to understand how to move from fault diagnosis to fault tolerance. Moreover, this chapter presents the fault tolerant control algorithms applied to dynamic processes. In general, they are based on the signal correction principle, which means that the control system is not modified since the inputs and outputs of the baseline controller are compensated according to the estimated faults. The fault tolerant control algorithms recalled in this chapter rely on the fault diagnosis design for nonlinear systems addressed in the monograph. Passive and active fault tolerant control systems are also discussed and compared, in order to highlight the achievable performances and the complexity of their design procedures. Controller reconfiguration mechanisms are also considered, which are able to guarantee the system stability and satisfactory performance.