Optimized Fractional-Order Type-2 Fuzzy PID Attitude Controller for Fixed-Wing Aircraft

This paper addresses the design of attitude controller for a fixed-wing unmanned aerial vehicle. To address the complexity of the coupled nonlinear model of a fixed-wing aircraft, this paper introduces a Fractional-Order Type-2 Fuzzy PID (FOTFPID) controller. The adoption of interval valued type-2 fuzzy sets, as an extension of conventional fuzzy sets, has endowed decision makers with the ability to assign membership and non-membership values as intervals. This enhanced capability facilitates more resilient decision-making processes. The Bat optimization algorithm is also employed to fine-tune the membership functions, scaling factors, and primary controller parameters, aiming to minimize the integrated absolute error index. Numerical simulations are conducted to demonstrate effectiveness of the proposed controllers in comparison to classical PID controllers, while subjecting the aircraft system to various disturbance conditions.