Trajectory Tracking Control for Parafoil Systems Based on the Model-Free Adaptive Control Method

Parafoil systems are unique steerable decelerator systems. However, due to the strong nonlinearity caused by the flexibility of the canopy and the suspension lines, the existing dynamic models of parafoil systems are not sufficiently accurate enough; and hence, existing model-dependent control methods are not suitable for practical applications. To effectively eliminate the influence of inaccurate models on trajectory tracking, this paper introduces a novel real-time model-independent control method named the model-free adaptive control (MFAC) method. The stability of the MFAC method is theoretically deduced, and the robustness of this approach is analyzed and demonstrated by the Monte Carlo method. To assess the performance of the MFAC method, a six-degree-of-freedom (DOF) dynamic model is built, and then a series of simulations are performed under different conditions. The simulation results demonstrate the effectiveness of the proposed MFAC method in trajectory tracking. Compared with the proportional/integral/derivative (PID) control method and the active disturbance rejection control (ADRC) method, the MFAC method has higher precision and lower energy consumption, especially under complex disturbance conditions.