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.

中文翻译：

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飞机EMA制动系统颤振抑制快速终端滑模控制


飞机制动系统中机电执行器（EMA）的性能受到系统非线性特性的影响，而鲁棒控制有助于提高其伺服系统的跟踪精度。本文针对 EMA 制动系统提出了一种嵌入非线性扰动观测器 (NDO) 的抖振抑制快速终端滑模 (FTSM) 控制策略，该策略可以保留经典 FTSM 的快速收敛特性，并保证系统收敛于及时达到平衡点。此外，通过精心设计的滑模流形解决了经典FTSM控制的奇异性问题。 NDO 旨在在线估计不确定因素，包括 EMA 系统的时变参数、外部干扰和未成型动态。通过将补偿项应用到控制律中，所提出的控制策略可以减轻抖振问题并提高系统稳定性。为了验证所提出的 EMA 控制策略的性能，在有关跑道类型和故障情况的各种条件下进行了车轮制动测试。结果表明，所提出的控制策略能够保证EMA伺服系统的伺服性能、控制精度和响应速度。