Automated systems are vulnerable to faults such as defects in sensors or in actuators
and failures in controllers or in control loop, which can cause undesired reactions and
consequences as damage to technical parts of the plant, to personnel or to the environment. For this reason fault tolerant control is an emerging key area in automatic control.
The principal aim is to avoid that local faults will develop into failures that can cause safety hazards. This is obtained by reconfiguring control using information from fault diagnosis and fault identification.
This paper focuses on the fault-tolerance problem applied to a ship propulsion system. This system has been developed by the Control Engineering Department of Aalborg University as a benchmark for fault tolerant control algorithms and can be downloaded at the url http://www.control.auc.dk/ftc/ and it has attracted much interest in the control
community, since it faithfully reproduces the real behavior of the ship in terms of disturbances acting on the system, of behavior of internal dynamics, of nonlinearities present in the dynamics. After a brief description of the overall
system, in this paper is given an analysis of the possible faults acting on the system on the basis of the so-called Failure Mode and Effects Analysis (FMEA),which represents an
internationally accepted method for the classification of the faults (and hence for the evaluation of their gravity).
After this preliminary analysis, a simple Fault Detection and Isolation strategy based on test on control system is described, which allows perfect isolation of the three possible faults proposed in the benchmark. The information provided by the FDI are then used to develop a control reconfiguration structure in order to achieve a fault tolerant
control system, able to preserve pre-specified performance also in presence of faulty situation. Simulation results, showing the effectiveness of the control structure presented in the paper, conclude the work.