Optimized interval type-2 fuzzy PID control for quadcopter trajectory tracking under disturbances

Quadcopters are inherently nonlinear and underactuated systems, making robust trajectory control a challenging task, particularly in the presence of external disturbances such as wind gusts and sensor noise. This study proposes a novel interval type-2 fuzzy proportional integral derivative (IT2-FPID) controller for simultaneous regulation of altitude and attitude of a quadcopter. The key novelty of the proposed approach lies in the simultaneous optimization of both the PID gains and the IT2-FLC rule base using particle swarm optimization (PSO), which ensures an optimal balance between transient responsiveness and disturbance rejection, an aspect not addressed in prior IT2-FPID studies. The proposed controller integrates the uncertainty handling capability of an interval type-2 fuzzy logic controller (IT2-FLC) with the simplicity of a conventional PID structure, resulting in a model-free and computationally efficient control framework. The complete control system is implemented and simulated in MATLAB®/Simulink. The performance of the proposed IT2-FPID controller is evaluated against type-1 fuzzy PID (T1-FPID) and conventional PID controllers under both nominal and disturbed conditions, with all controllers tuned using PSO under identical settings for fair comparison. The proposed IT2-FPID controller achieves superior results, improving settling time by 23.49%, 11.27%, and 16.53% for altitude, roll, and pitch, respectively, compared to the T1-FPID controller. Furthermore, the proposed controller maintains robust performance under aerodynamic disturbances and sensor noise, confirming its practical applicability in real-world flight scenarios.