The high-speed, low-altitude region in the flight envelope of a wing-in-ground (WIG) effect craft requires attitude angle limitations to protect the aircraft from touching the ground or sea surface, and the safe boundaries of the attitude angles are time-dependent related to the flight height. This paper presents a command governor design for attitude angle protection of a WIG craft. In particular, this command governor adjusts the calculation of attitude angle boundaries and improves the maximal admissible $\lambda \text{-}\mathrm{contractive}$ set to handle the varying constraints. A set-membership state estimator is also employed to address the unmeasured disturbances and noise. The command governor design for pitch angle and bank angle protection is verified by simulation cases of climbing and turning of a WIG craft. The simulation results illustrate that the command governor can predict potential constraint violations and modify the pilot’s commands to handle the varying constraints as well as the contracted constraints affected by the measurement noise. The wing-in-ground effect craft is a kind of aircraft flying close to the ground or sea surface. The airframe and the wingtips of these crafts may touch the sea surface during climbing or turning due to the low flight altitude. We use a control method called “command governor” to prevent this dangerous situation and ensure flight safety. The command governor can guarantee the attitude angles of the aircraft within the safe boundaries by predicting potential constraint violations and modifying the pilot’s commands. In particular, we improve the command governor to handle the varying constraints as well as the contracted constraints affected by the wave disturbances and the measurement noise.

For aircraft employing the fly-by-wire technique, the closed-loop dynamic characteristics are determined by both the configuration design and the flight control system. As the capacity of the control system has certain limitations, the configuration parameters are also constrained by the requirements of the closed-loop flying qualities. This paper presents an aircraft configuration parameter boundaries determination method based on closed-loop flying qualities requirements independent of the actual flight control law design, mainly aiming at the parameters that affect the stability and control characteristics. First, a nonlinear dynamic inversion-based flight control law is adopted to decouple the control law gains from the configuration parameters and to study the relationship between the configuration parameters and closed-loop flying qualities. Second, a flying qualities evaluation scheme is established by selecting the most severe flight conditions and the evaluation criteria that are most sensitive to changes in the parameters. Finally, the parameter boundaries according to the requirements of Level 1 flying qualities are determined by searching for the critical values that lead to degradation of the flying qualities. The proposed method is verified by an application example of the design ranges of a sample aircraft’s wing position, horizontal tail area, center of gravity, vertical tail area and vertical tail position.