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The performance of the electromechanical actuator (EMA) in the aircraft braking system suffers from the system’s nonlinear characteristics, whereas the robust control can contribute to the improvement of tracking precision in its servo system. In this article, a chattering suppression fast terminal sliding mode (FTSM) control strategy with an embedded nonlinear disturbance observer (NDO) is proposed for the EMA braking system, which can retain the fast convergence characteristic of the classical FTSM and guarantee the system converges to equilibrium point timely. Moreover, the singularity problem of the classical FTSM control is resolved through the well-designed sliding mode manifold. The NDO is designed to estimate the uncertain factors online, including time-varying parameters, external disturbance, and unmolded dynamics of the EMA system. By applying the compensation terms into the control law, the proposed control strategy can alleviate the chattering problem and improve system stability. To verify the performance of the proposed control strategy for EMA, wheel braking tests are conducted under various conditions regarding the type of runway and failure cases. The results indicate that the proposed control strategy can guarantee the servo performance, the control precision, and the response speed of the EMA servo system.

The existing controller can hardly guarantee the operating stability of aircraft anti-skid braking system. To overcome the higher order nonlinearity and parameters variability of large passenger aircraft with electro-hydrostatic actuator (EHA) anti-skid braking system, a dynamic surface control approach, which based on barrier Lyapunov function (BLF), is proposed to design a slip ratio tracking control with an upper constraint. The purpose of the proposed BLF is to prevent constraint violation to ensure stability. A whole state space model of EHA anti-skid braking system is developed and simplified reasonably to a strict feedback form, whose model uncertainties are considered as unknown external disturbances. A nonlinear disturbance observer (NDO) is utilized to compensate this external disturbance. Through Lyapunov stability analysis, it is noticed that the proposed control strategy can converge to a small neighborhood of the origin by appropriately adjusting the controller parameters. Moreover, it can guarantee the tracking error is with semiglobal, uniform, and ultimate bounded. By using the employed control algorithm, the proposed controller enhanced braking performance and safety, which ensures the closed-loop system operating in the stable region of the friction curve. The proposed method eliminated the explosion problem of terms existing in traditional back-stepping approach and was easier to be implemented. The performance and the effectiveness of the proposed controller have been verified by carrying out simulation and real-time Hardware-in-Loop experiment.

Focus on the ripple of the output voltage of switched reluctance generator (SRG), an optimized controller of turn-on and turn-off angle basing on fuzzy logic is designed. The effect of turn-on and turn-off angle on system's performance is studied after introducing the working principle of SRG. Considering the ripple of output voltage and the difference between the real voltage and the reference voltage, the voltage of SRG is limited near the reference voltage by optimizing the turn-on and turn-off angle through fuzzy logic method. The self-exciting SRG model which adopts voltage feedback control is built to validate this controller's correctness and robustness. Compared with traditional PI control method, the fuzzy logic algorithm can restrain the voltage ripple and strengthen system's static performance well.

The design requirements of brushless DC (BLDC) motor control system are on the increase high with the continuously broaden application fields of it. This paper presents the direct torque control(DTC) drive scheme for BLDC motor. The rationale of DTC for BLDC motor is analyzed and torque error is directly used to control the inverter states. The magnitude and phase angle of stator flux linkage vector are deduced under the α-β axis stationary reference frame. The control algorithm of stator flux linkage and torque is hysteresis control, then the results and flux linkage regulate the inverter. MATLAB simulation results indicate that DTC scheme for BLDC motor has faster speed of torque response and better performance, achieve the purpose.

With the background of the development of Aircraft Anti-skid Braking System, a new aircraft Electro-Hydrostatic Actuator (EHA) of a certain model fighter is designed to meet the need of the braking system. The paper describes the principle of work and features of the EHA, and gives the specific requirements of the system. The selection and performance of the motor, pump and hydraulic cylinder are optimized. Then, the paper describes the principle of work and features of the EHA, models and simulates it with MATLAB/Simulink., and analyzes the effects of all structural parameters on the performance. The results of EHA reach the design target of dynamic performance. Finally, the whole model of the aircraft system is built and established based on the EHA model and results. The results of the dry runway condition verify the correctness of the EHA design, so the Hydro Actuator of traditional aircraft anti-skid braking system could be replaced by EHA.