Improved prescribed performance control for multi-quadrotor payload transport under unknown disturbances

This paper presents a robust and enhanced control strategy for a multi-quadrotor suspended payload system, which is characterized by complex nonlinear dynamics and unknown external disturbances. A precise dynamic model of the system is formulated using the Udwadia–Kalaba method. A distributed cooperative planning framework, based on graph theory, is employed to enable effective information exchange and cooperative control among multiple quadrotors. To mitigate the impact of unknown disturbances, such as wind fields and variations in payload mass, a disturbance observer is developed to estimate and compensate for these disturbances, thereby enhancing system robustness. Furthermore, an improved prescribed performance control method is proposed to address the issue of exceeding performance boundaries. The steady-state error of the system is effectively reduced by adaptively adjusting the prescribed performance boundary and combining it with integral backstepping, and real-time constraints on tracking errors and closed-loop stability are achieved. Simulation results validate that the proposed control strategy significantly enhances the control performance and disturbance rejection capability of the multi-quadrotor suspended payload system, demonstrating superior robustness.