Prescribed Performance Adaptive Sliding Mode Control for Foldable Quadcopter UAV

Foldable quadcopter represent a new frontier in aerial robotics technology. The ability of foldable quadcopter to reconfigure its geometry inflight and adapt its self to various flight scenarios offer enhanced agility, maneuverability, aerodynamic efficiency, and mission versatility compared to traditional quadcopter. However, the folding function introduces significant parameter variations such as center of gravity, inertia, and nonlinear dynamics in addition to inherent underactuation, coupling dynamics, and external disturbances. Thus, folding mechanism presents significant challenges to conventional control approaches. To solve the drawbacks of conventional control approach, this article proposed the development of prescribed performance adaptive sliding mode control (SMC) for foldable quadcopter UAV. It models the morphing quadcopter as rigid body system with five morphing formations (X, Y, H, O, and T). The prescribed performance SMC approach systematically addresses the time varying parameter and aerodynamic impact resulting from the morphing formation. Using Lyapunov theory, the adaptive SMC that ensures the error evolution is within prescribed performance bounds, the closed loop stability, and precise trajectory tracking under parametric and nonparametric uncertainties is designed.The effectiveness of the proposed control algorithm is evaluated and benchmarked via simulation in structured and unstructured environment against conventional sliding mode control (SMC), PID, and LQR control methods. The simulation results indicate the performance of the adaptive SMC, improved robustness, and adaptability compared to benchmarked control methods. The simulation results demonstrated that, adaptive control approach is a viable and effective solution for managing the complex dynamics and uncertainties of foldable quadcopter UAV.