Global integral sliding mode control for ultra-low-altitude airdrop in extraction parachute failure state

To reduce the impact on the flight safety and the airdrop mission completion from the extraction parachute failure, a novel controller based on the global integral sliding mode control is designed. Firstly, the open-loop characteristic of the carrier in extraction parachute failure state is analyzed. Then, the system is decoupled and linearized using the nonlinear linearization theories of input-output feedback. On this basis, by applying the two-rank iterative global integral sliding mode control, we design the inner loop for velocity control and pitch control. Combining the inner loop control with the outer loop PID control for flight-altitude, we build the entire flight control system which improves the dynamic performance of the system. Finally, simulation results show that the controllers have strong robustness for fault state.