Active fault-tolerant control of dissimilar redundant actuation system based on performance degradation reference models

Dissimilar redundant actuation system (DRAS) composed of one hydraulic actuator (HA) and one electro-hydrostatic actuator (EHA) represents industry trend in actuation system towards more electric aircraft (MEA). The paper investigates performance degradation of DRAS under the system malfunctions and addresses the problem of active switching of DRAS from HA to EHA to ensure the reliable actuation and efficient control. A novel active fault-tolerant controller (AFTC) based on the performance degradation reference models (PDRM) is presented. The main performance degradation rules of DRAS are determined based on the effect of fault degree on the system root locus and the proposed PDRM are then constructed as a series of second-order functions. Finally, an intelligent matching algorithm (MA) is developed based on the dominant closed-loop poles, and a set of adaptive fuzzy controllers (AFC) are designed based on the proposed PDRM and the intelligent MA to achieve the performance degraded fault-tolerant capability. Extensive simulation results are presented to indicate the effectiveness of the proposed AFTC control scheme.