Nonlinear H∞$$ {H}_{\infty } $$ Control Strategy for a Suspended Transport System of Dual Quadrotor UAVs

ABSTRACT This paper proposes a novel nonlinear control strategy for the suspended transport system of dual quadrotor Unmanned Aerial Vehicles (UAVs), aimed at achieving precise trajectory tracking under unknown disturbance. First, a non‐redundant model of the dual quadrotor UAVs' suspended transport system is established, which can greatly reduce the singular value problem. Then, a hierarchical control structure is designed. For the outer‐loop subsystem, a novel nonlinear control strategy is proposed. This approach incorporates the integral effects of all degrees of freedom in the state space representation. The integral effects of the uncontrolled degrees of freedom are integrated into the cost function. The nonlinear controller is then designed within a weighted Sobolev space framework. Subsequently, the stability of the closed‐loop system is established via Lyapunov's theorem, and the analytical solution of the control law is derived. For the inner loop subsystem, Active Disturbance Rejection Control (ADRC) is employed. Comparative simulations demonstrate the proposed controller's superior performance and robustness over existing methods.