Sliding Mode Control of Quadcopter Suspended Payload System with Elastic Cable

As drone technology rapidly advances, quadrotor suspended load systems have emerged as a key area of application. During drone flight, swinging of the payload can induce quadrotor oscillations, potentially leading to crashes. Most of Current studies have simplified the connection between drones and payloads as rigid rods, neglecting the influence of internal forces within the cables. This paper proposes to model the connection cables as an elastic damping system, establishing a dynamic model for quadrotor suspended payload system with an elastic cable (QSPSE). By employing a nonsingular fast terminal sliding mode (NFTSM) control method, a swing angle controller is devised. Without modifying the original controller structure, the swing angle information is integrated as feedback into the position controller to realize swing angle control. Simulation results demonstrate that the proposed controller effectively suppresses payload swinging while achieving position tracking.