Robust fault-tolerant servo system against sensor failure and plant uncertainties

This paper concerns with a design of robust fault-tolerant servo systems against sensor failures and plant uncertainties. The method already exists which estimates sensor failures with disturbance observer, and, constitutes a fault-tolerant control system. In this method, generally the optimal regulator theory is used to design a controller. However, this approach is not easy to consider the robustness against plant uncertainties. In this paper, a method for designing a robust fault-tolerant controller is proposed. This method enables us to consider the robustness by applying H
_∞
control theory. The effectiveness of the proposed design procedure is demonstrated by a numerical example.