Fuzzy logic based closed-loop strapdown attitude system for unmanned aerial vehicle (UAV)

This paper describes the development of a fuzzy logic based closed-loop strapdown attitude reference system (SARS) algorithm, integrated filtering estimator for determining attitude reference, for unmanned aerial vehicles (UAVs) using low-cost solid-state inertial sensors. The SARS for this research consists of three single-axis rate gyros in conjunction with two single-axis accelerometers. For the solution scheme fuzzy modules (rules and reasoning) are utilized for online scheduling of the parameters for the filtering estimator. Implementation using experimental flight test data of SURV-1 Sejong UAV has been performed in order to verify the estimation. The proposed fuzzy logic aided estimation results demonstrate that more accurate performance can be achieved in comparison with conventional fixed parameter filtering estimators. The estimation results were compared with the on-board vertical gyro used as the reference standard or 'truth model' for this analysis. (C) 2003 Elsevier B.V. All rights reserved.