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Appearing faults in a practical system is dispensable, and if it is not compensated, it results in poor system performance or even dysfunction of the system. The fault detection has become a promising challenging issue to guarantee the safety and reliability of systems. In this paper, a novel fuzzy-based sliding mode observer for the simultaneous actuator and sensor fault reconstruction of nonlinear systems subjected to external disturbance is proposed. The proposed approach employs the Takagi-Sugeno fuzzy model, sliding mode observer and non-quadratic Lyapunov function. First, by filtering the system output, a fictitious system whose actuator faults are the original actuator and sensor faults is constructed. Then, by considering the [Formula: see text] performance criteria, the effect of disturbance on the state estimations is minimized. It is proved that the estimations asymptotically converge to their actual values for non-perturbed systems. In the process of designing the observer gains, some transformation matrices are obtained by solving linear matrix inequalities. The proposed approach has some superiority over the existing methods. First, considering the non-quadratic Lyapunov function leads to relaxed results and good estimation performance. Second, using the sliding mode observer makes the proposed approach insensitive to the uncertainties and unknown inputs and determines the shape and size of the fault. Third, assuming the premise variables are immeasurable makes the presented approach more applicable. In conclusion, two practical systems are considered and simulation results illustrate the merits of the proposed approach in comparison with the recent methods from the fast and precise fault detection performance viewpoints.

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IntroductionThe inferior turbinate is a critical and dynamic structure during rhinoplasty in the internal valve. Many surgeons try to preventively reduce its resistance against the path in the post-rhinoplasty period. To this end, the two methods of “sub mucosal partial inferior turbinectomy” and “inferior turbinate out fracture” are compared in the present study.MethodsIn this clinical study, 110 rhinoplasty candidates were randomly divided into two groups, namely sub mucosal partial inferior turbinectomy and out fracture of the inferior turbinate. To assess the complications, the Sino-Nasal Outcome Test (SNOT-22) was used prior to surgical intervention, and 1, 2, 3, 6, and 12 months following the rhinoplasty procedures.ResultsBased on the results of this clinical study and according to the SNOT-22 questionnaire, there was no significant difference between the two groups prior to surgery and a month following the surgery (P > 0.05). However, the average SNOT-22 score for the sub mucosal partial inferior turbinectomy group was significantly lower than that of the group with the out fracture of the inferior turbinate, 2, 3, 6, and 12 months following the surgery.ConclusionBoth “sub mucosal partial inferior turbinectomy” and “out fracture of inferior turbinate” are effective methods in improving the respiratory function of rhinoplasty patients, yet the former method is more effective than the latter as regards improving the respiratory function of patients.Level of Evidence IVThis journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

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