a b s t r a c tFault detection for aileron actuators mainly involves the enhancement of reliability and fault tolerant capability. A fault detection method for aileron actuator under variable conditions is proposed in this study. In the approach, three neural networks are used for fault detection and preliminary fault localization. The first neural network, which is employed as an observer, is established to monitor the aileron actuator and estimate the system output. The second neural network generates the corresponding adaptive threshold synchronously. The last neural network is used as a force motor current observer, and outputs estimated force motor current. Faults are detected by comparing the residual error (the difference value between the actual and estimated output) and the threshold, or comparing the force motor current and the estimated force motor current. In considering of the variable conditions, aerodynamic loads are introduced to the neural network, and the training order spectrums are designed. Finally, the effectiveness of the proposed scheme is demonstrated by a simulation model with different faults.

The optimal design of transmitted waveforms to improve the performance of missileborne radar in suppressing interrupted sampling repeater jamming (ISRJ) is studied here. The waveform diversity property requires that the waveform group has excellent orthogonality (good auto-and cross-correlation properties), which is an effective waveform optimisation design method for missile-borne radar electronic countercountermeasures. The principle of orthogonal phase coding waveform against ISRJ is studied and the use of chaotic sequences is proposed to initialise the population, as well as a simulated annealing selection operator, which improves the convergence speed of the improved genetic algorithm (IGA) and enhances the global optimisation ability. The IGA improves the shortcomings of GA, that is, easily falling into a local optimum and slow search speed, and can realise a global search for longer orthogonal polyphase coding sequence sets. The simulation examples demonstrate the good jamming suppression performance of the proposed method.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.