Robust control of a class of nonlinear uncertain systems. Fault tolerance against sensor failures and subsequent self recovery

The problem of designing a fault-tolerant robust control for a class of nonlinear uncertain systems is investigated. Possible failures of the sensors measuring the state variables are considered, and robust measures are developed to identify the stability-vulnerable failures. Based on an evaluation of the robust measures, a fault-tolerant robust control can switch itself among several robust control strategies designed under normal operation and under specific faulty conditions. It is shown that, under mild conditions, the proposed scheme guarantees not only the desired performance under normal operations but also robust stability and best achievable performance when there is a sensor failure of any kind