Second order sliding mode control for a quadrotor UAV.

Area of Science:

• Robotics
• Control Systems Engineering
• Aerospace Engineering

Background:

• Quadrotor unmanned aerial vehicles (UAVs) require sophisticated control systems for stable flight.
• Designing controllers for UAVs is challenging due to complex nonlinear dynamics.
• Second-order sliding mode control (2-SMC) offers robustness but faces challenges with nonlinear coefficient selection.

Purpose of the Study:

• To propose a novel 2-SMC-based control method for precise position and attitude tracking in small quadrotor UAVs.
• To address the complexity of nonlinear coefficient selection in switching sliding manifold design.
• To ensure system state trajectories remain on sliding surfaces for guaranteed stability.

Main Methods:

• The quadrotor's dynamical model is divided into fully actuated and underactuated subsystems.
• Sliding manifolds are designed for each subsystem, incorporating position and velocity tracking errors.
• Nonlinear coefficients are determined using Hurwitz stability analysis.
• Lyapunov theory is employed to derive flight controllers.

Main Results:

• The proposed 2-SMC method enables effective position and attitude tracking control for quadrotors.
• The controller design successfully handles the nonlinear dynamics of the UAV.
• Simulation results demonstrate the superior performance and stability of the developed control strategy.

Conclusions:

• The presented 2-SMC approach provides a robust and effective solution for quadrotor UAV control.
• The method simplifies the design process by systematically determining nonlinear sliding manifold coefficients.
• This work contributes to advancing autonomous flight capabilities in small UAVs.