Extreme aircraft maneuver under sudden lateral CG movement: Modeling and control

Hitherto unaddressed issue of six degree-of-freedom transient dynamics during asymmetric ejection of stores with finite velocity, onboard a combat aircraft, is addressed and modeled from the first principle. Further, the effect of asymmetric center-of-gravity shift, post ejection of the store, on some complex high angle-of-attack maneuvers such as cobra and Herbst is also investigated. It is shown that the performance of the maneuvers drastically deteriorates when carried out with controller designed for the pre-ejection symmetric c.g. based dynamics. In order to improve the deteriorated performance, two new control schemes based on the standard sliding mode technique are proposed. The first sliding control is designed based on a simple ad-hoc model for the asymmetric dynamics, whereas the states are propagated using the exact model developed. It is shown that using this scheme the lost maneuver performance can be reasonably recovered. The second control scheme is formulated using an accurate asymmetric dynamics. This proposed control scheme almost completely recovers the original maneuver performance.