This paper presents a networked fault-tolerant control strategy based on control allocation which is applied to a modern aircraft. The proposed method utilizes the benefits of networked control system architecture in which smart sensors/actuators are interconnected through a bi-directional digital communication network. A smart actuator, the paper focuses on, is capable of providing the supervisor level with various information on the device itself. This information on the device condition is then used to tolerate faulty actuators by re-allocating redundant actuators. Simulation results with an aircraft show that the proposed method can achieve a fast and effective compensation in the presence of actuator faults.

Dynamic inversion (DI) is a control synthesis technique that steers the system states to track the desired trajectory by cancelling the original dynamics. However, it is impossible to achieve perfect cancellation of the original dynamics in real applications, robustness problem must be considered in designing DI controller. In this paper, robust dynamic inversion (RDI) control strategy based on sliding mode control (SMC) is proposed. Different from the previous works of achieving robustness in DI controller, the proposed RDI controller is designed inherently robust. Moreover, robust observer strategy based on the RDI controller is also proposed in this paper. Numerical simulations with application to the AV-8A Harrier aircraft demonstrate the effectiveness of the proposed method.

ABSTRACT:The mechanical and heat-resistant properties of acrylonitrile-butadienestyrene (ABS) binary and ternary blends were investigated. The relationship of compatibility and properties was discussed. The results show that poly(methyl methacrylate) (PMMA) and styrene-maleic anhydride (SMA) can improve the thermal properties of conventional ABS. The Izod impact property of ABS/PMMA blends increases significantly with the addition of PMMA, whereas that of ABS/SMA blends decreases significantly with the addition of SMA. Blends mixed with high-viscosity PMMA are characterized by higher heat-distortion temperature (HDT), and their heat resistance is similar to that of blends mixed with SMA. For high-viscosity PMMA, from 10 to 20%, it is clear that blends appear at the brittle-ductile transition, which is related to the compatibility of the two phases. TEM micrographs show low-content and high-viscosity PMMA in large, abnormally shaped forms in the matrix. Compatibility between PMMA and ABS is dependent on both the amount and the viscosity of PMMA. When the amount of high-viscosity PMMA varied from 10 to 20 wt %, the morphology of the ABS binary blends varied from poor to satisfactory compatibility. As the viscosity of PMMA decreases, the critical amount of PMMA needed for the compatibility of the two phases also decreases. SMA, as a compatibilizer, improved the interfacial adhesiveness of ABS and PMMA, which results in PMMA having good dispersion in the matrix.

Early detection and diagnosis of wind turbine faults is critical for applying a possible maintenance and control strategy to avoid catastrophic incidents. This paper presents a novel method to estimate the parameter of faults in a wind turbine. In this work, the estimation of fault parameters is reformulated as the state estimation problem by augmenting the parameters as an additional state. The novelty of the proposed method lies in the use of an adaptive fuzzy fading algorithm for the adaptive Kalman filter so that the convergence property during the estimation of fault parameter can be improved. The performance of the proposed method is evaluated through a set of numerical simulations with both linear and non-linear models.

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