Practical Rules for the Stability Analysis of Flight Control Electrically Actuation System

Abstract

With the development of more electric aircraft (MEA), the electrically powered actuators of electromechanical actuator (EMA) and electro-hydrostatic actuator (EHA) are becoming increasingly significant in flight controls. Generally, in the preliminary stage of EHA and EMA design, the performance analysis is always based on the linear models, the nonlinearities of inner actuator and load transmission are ignored, which results in inconsistent control characteristics, while the displacement output of the system is not expected and sometimes even unstable, and increase the difficulty of the regulation of control parameters. To figure out the effects of nonlinearities, the practical rules are proposed to easily and well conduct the stability analysis of actuation system. Aiming at the mentioned difficulties, this paper analyses the typical nonlinearities of electrical actuation system. EHA and EMA models are developed and the impacts on stability of each nonlinearities are analyzed. In order to reduce the influence of nonlinearities, controller parameters are optimized according to the practical rules. The whole research processes are summarized as the proposed method of analyzing the nonlinear effects on the stability, which combine the method of model-based system engineering (MBSE). These rules narrow the gap between virtual prototype and realistic system and makes the control design is much more convincing and more accurate.