Command Governor for Constrained Attitude Angle Protection of the Wing-in-Ground Effect Craft near Sea Surface

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 λ-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.