Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
School of Mechanical and Electronic Engineering, University of Chinese Academy of Sciences, Beijing 100039, China.
Sensors (Basel). 2018 Dec 15;18(12):4449. doi: 10.3390/s18124449.
Electromechanical actuator (EMA) systems are widely employed in missiles. Due to the influence of the nonlinearities, there is a flat-top of about 64 ms when tracking the small-angle sinusoidal signals, which significantly reduces the performance of the EMA system and even causes the missile trajectory to oscillate. Aiming to solve these problems, this paper presents a hybrid control for flat-top situations. In contrast to the traditional PID or sliding mode controllers that missiles usually use, this paper utilizes improved sliding mode control based on a novel reaching law to eliminate the flat-top during the steering of the input signal, and utilizes the PID control to replace discontinuous control and improve the performance of EMA system. In addition, boundary layer and switching function are employed to solve the high-frequency chattering problem caused by traditional sliding mode control. Experiments indicate that the hybrid control can evidently reduce the flat-top time from 64 ms to 12 ms and eliminate the trajectory limit cycle oscillation. Compared with PID controllers, the proposed controller provides better performance-less chattering, less flat-top, higher precision, and no oscillation.
机电执行器 (EMA) 系统在导弹中得到了广泛应用。由于非线性的影响，在跟踪小角度正弦信号时会出现约 64ms 的平顶，这显著降低了 EMA 系统的性能，甚至导致导弹轨迹振荡。为了解决这些问题，本文提出了一种针对平顶情况的混合控制方法。与导弹通常使用的传统 PID 或滑模控制器不同，本文利用基于新型趋近律的改进滑模控制来消除输入信号转向过程中的平顶现象，并利用 PID 控制来替代不连续控制，提高 EMA 系统的性能。此外，采用边界层和切换函数来解决传统滑模控制引起的高频抖动问题。实验表明，混合控制可以将平顶时间从 64ms 显著缩短至 12ms，并消除轨迹极限环振荡。与 PID 控制器相比，所提出的控制器具有更好的性能——更少的抖动、更小的平顶、更高的精度和无振荡。
