Health Parameter Estimation with Second-Order Sliding Mode Observer for a Turbofan Engine

Due to the property of the discontinuous switched term, when a sliding motion is induced the observer is able to robustly estimate states/faults considering uncertainties. [...]sliding mode observer has been widely used in robust state estimation [17,18,19], constructing fault detection and isolation (FDI) scheme [20], detecting actuator faults [21] and handling sensor faults [22,23,24]. Once sliding motion is achieved, a weighting matrix is designed to minimize the disturbance effect on the health estimation via linear matrix inequalities (LMI). Since robustly reaching the sliding surface is ensured by super-twisting algorithm and robustly estimation after sliding reaching is enabled by the weighting matrix, there is no any restrictions on uncertainty formulation. Long-time degradation and these sudden damages both result in the change of component performance and characteristics, such as capacity and efficiency. [...]the flow capacity and efficiency of engine components are chosen as “health parameters” to reflect component health performance. [...]Figure 4c shows the results conducted by SOSMO, with a desired accuracy and detection times.