A robust adaptive control framework for flight environment testbed system with unknown dead-zone

To improve the control precision and robustness of Flight Environment Testbed System (FETS) under actuator dead-zone nonlinearity and external disturbances, this paper proposes a robust adaptive control method based on a dual-layer structure. Unlike traditional inverse-based compensation approaches, the proposed method eliminates the need for explicit dead-zone modeling by embedding a robust adaptive compensation mechanism directly into the control loop. Moreover, a Generalized Proportional-Integral Observer (GPIO) is incorporated to estimate unmeasurable lumped disturbances and their derivatives, enhancing system adaptability under parametric uncertainties. The control law ensures global asymptotic stability, which is strictly proven using Lyapunov theory. Hardware-in-the-loop simulation experiments are conducted to validate the proposed method against the Nonlinear Active Disturbance Rejection Control (NLADRC) and the Linear Active Disturbance Rejection Control (LADRC) schemes. The results demonstrate that the proposed controller achieves faster transient response, lower tracking error, and smoother actuator motion across a range of operational scenarios.