Modeling and anti-swing control of quadrotor-suspended system with variable cable length at unequal speed

Aiming at the problem of payload’s swing and communication resource saving of the quadrotor-suspended system under external disturbances, this paper proposes a modeling and control scheme of the quadrotor-suspended system with variable cable length at unequal speed. The inner loop adopts adaptive sliding mode control to enhance the robustness of the system and anti-swing feedforward control to suppress the swing angle, and the outer loop uses improved PD control to track the reference trajectory. Meanwhile, an event-triggered strategy based on dynamic threshold is designed in the inner loop controller, which reduces communication resource occupation. The stability of the coupled nonlinear control system is proved, and the event-triggered strategy can avoid Zeno behavior. Simulation results show that the scheme proposed in this paper can make the quadrotor track the desired trajectory, effectively suppress the payload swing, and save communication resources.