Development of a high redundancy actuator with direct driven linear electromechanical actuators for fault-tolerance

The High Redundancy Actuator (BRA) deals with the intrinsic fault-tolerance actuation by having a large number of small actuation elements coupled in series and parallel configuration to form as a single actuator. There is a wide range of actuation elements that are suitable for a BRA, but the present work focused on a direct-driven linear Electromechanical Actuator (EMA). The actuation elements are connected in 3X3 series-in-parallel configuration in the BRA. The mathematical modeling of a single EMA was derived and the equations were solved using MATLAB/Simulink module. Based on the results obtained from the mathematical model, an iconic model of HRA with nine actuation elements was modeled using Simulink/simscape module. The performance of the 3x3 HRA was projected in both open and closed -loop under healthy and faulty conditions. It was observed that there is no sudden failure of actuation, but there is a graceful degradation in the performance of actuation depending upon the number of faulty elements. However, the actuator completes the required task even after the failure of three actuation elements within the BRA. (C) 2018 The Authors. Published by Elsevier Ltd.