Design of fault-tolerant control for MTTF

Mean time to failure (MTTF) is an important reliability index of fault-tolerant control systems, which is chosen as a design objective in this paper. However, it is usually evaluated from stochastic reliability models. and no analytical expression is available to relate MTTF to controller parameters. To overcome this difficulty. a two-stage design scheme is proposed in this paper: A gradient-based search is firstly carried out on probabilistic H-infinity performance characteristics for MTTF requirement; a sequential randomized algorithm with a weighted violation function is then developed for a controller design to satisfy the required H-infinity performance, and its convergence is guaranteed with probability 1. Two iterative algorithms are carried out alternately to implement this scheme. and a controller can be designed for MTTF requirement. Copyright (C) 2008 John Wiley & Sons, Ltd.