Anti-disturbance control of tethered towed vehicle with unknown time-varying aerodynamic parameters and complex disturbance

Due to wind disturbances and various uncertainties, maintaining the stability of a tethered towed flight system is extremely challenging. This study proposes an anti-disturbance cooperative control scheme for a towed vehicle equipped with a flexible canopy. The proposed scheme effectively mitigates the impact of time-varying external disturbances, model uncertainties, and state and output constraints. Unlike existing studies, this paper addresses the unknown time-varying aerodynamic parameters of a tethered towed vehicle for the first time. Additionally, by integrating an adaptive neural network with a disturbance observer, a composite estimator is developed to tackle the effects of model uncertainties and time-varying disturbances. The state-constrained problem is addressed using an anti-saturation method based on auxiliary systems. The uniform boundedness of the controller signal is proven using the Lyapunov method. Numerical simulations validate the effectiveness of the proposed method in terms of disturbance rejection.