In this paper, a multi-objective fault-tolerant fixed-order output feedback controller design technique is proposed for multivariable discrete-time linear systems with unmeasured disturbances. Initially, a multi-objective fixed-order controller is designed for the system by transforming the problem of tuning the parameters of the controller into a static output feedback problem and solving a mixed H2∕H∞ optimization problem with bilinear matrix inequalities. Subsequently, the fixed-order controller is used to construct the closed-loop system and an active fault-tolerant control scheme is applied using the input/output data collected from the controlled system. Motivated by its popularity in industry, the proposed method is also used to tune the parameters of proportional-integral-derivative (PID) controllers as a special case of structured controllers with the fixed order. Two numerical simulations are provided to demonstrate the design procedure and the flexibility of the proposed technique.
