Combined fault monitoring detection and control

One of the advantages of polynomial methods is the insights the frequency domain approach provides. The relatively new subject of combined fault monitoring and control has mostly been considered in a state-equation form but is it more difficult to determine the frequency domain characteristics. A new solution of the combined fault estimation and control problem is presented in the z-domain and the resulting robustness and reliability benefits are identified. An H₂ cost-function is introduced that involves traditionally LQG cost terms and in addition fault estimation error components. The combined controller and fault estimator is economical to implement. The application of this methodology in ship roll stabilization problems is considered and the benefits of the approach are identified. The presentation is illustrated by a design example that considers both actuator and measurement system faults. The effect on the robustness of the control solution and the accuracy of fault prediction are discussed