A dual-loop scheme for fault-tolerance and early fault detection

An effective control system is typically expected to possess the capability of maintaining specified system performance despite changes in system parameters (faults). In some design strategies, this implies that the ´faults´ are automatically ´tolerated´ without being explicitly detected. On the other hand, early fault detection is a basic requirement of a fault diagnosis system, which is necessary for the long-term reliability of engineering systems. In order to achieve both effective control and long-term reliability, we propose a combined strategy, using separate loops for control and fault detection. A simulation example shows the effectiveness of the proposed scheme.