A frequency weighted approach to robust fault reconstruction

A new method for the design of robust fault reconstruction filters is introduced in this paper. The method is based on shaping the map from disturbance inputs to the fault estimation error through frequency weighting functions and formulating the problem as a robust observer design where the input-output error map is minimized by solving a set of matrix inequalities. A numerical example consisting of seven states, two input disturbances, four measured outputs and one fault is considered. Through this example, it is shown that the frequency shaping renders far superior performance than existing conventional methods when properly incorporated in the observer design problem.