Nonlinear Backstepping Control of a Quadrotor-Slung Load System

This paper presents a nonlinear backstepping controller designed for an underactuated quadrotor-slung load system that drives the load to a predefined trajectory. The quadrotor and the load are modeled as a rigid body and a point mass, respectively. The controller is designed through Lyapunov and backstepping techniques, and the control laws for thrust and angular velocity are presented, which guarantee the closed-loop system to be asymptotically stable. Experimental results are provided to assess the validity and performance of the proposed controller.