Fault Tolerant Control of EHA System Under Performance Degradation

Abstract

The industry trend in aircraft actuation systems towards more electric aircraft (MEA) is exemplified by the Dissimilar Redundant Actuation System (DRAS), which comprises a hydraulic actuator (HA) and an electro-hydrostatic actuator (EHA). This chapter delves into the performance degradation of the DRAS when confronted with system malfunctions. The focal point is on enabling active switching of the actuation system from HA to EHA, ensuring both reliability and efficient control. The research introduces a pioneering Active Fault-Tolerant Controller (AFTC) that draws from Performance Degradation Reference Models (PDRM). These PDRMs are established by deciphering the fundamental rules governing the performance degradation of the DRAS. This is achieved by analyzing the impact of fault severity on the system’s root locus. The resulting PDRMs are formulated as a sequence of second-order functions. Consequently, an Intelligent Matching Algorithm (MA) is devised, centered around the dominant closed-loop poles. Leveraging this algorithm, a set of Adaptive Fuzzy Controllers (AFC) is formulated. These controllers are rooted in the proposed PDRMs and the Intelligent MA, enabling the DRAS to maintain a certain level of fault-tolerant capability even under performance-degraded conditions. The efficacy of the outlined Active Fault-Tolerant Control scheme is substantiated through an array of extensive simulation results.