Flight Control of a Variable Span Cruise Missile

In this work the benefits of variable span morphing are considered, specifically with regards to the increased maneuverability of bank-to-turn cruise missiles. Along with an increase in range associated with variable span aircraft-in the case where both wings are equally extended-there is also the possibility of an additional advantage of higher control authority over both pitch and roll motions. In the case of roll control, one wing is extended while the other is contracted thus producing a moment about the longitudinal axis of the missile. Compared to conventional tail surface control, this moment can be substantial depending on the flight conditions. There is, however, some complexity involved in flight control of variable span aircraft; namely the shift of the missile’s center of mass and the dependence of the roll producing moment on the angle of attack. The following work attempts to address these complexities through nonlinear control. First, a full nonlinear model of the missile is presented that includes aerodynamic effects and changes in weight distribution. Nonlinear methods are then used to control the trajectory of the missile via the roll angle, angle of attack, and sideslip angle. The results show that, in comparison with conventional missile configurations, the addition of variable span morphing has the capability of increasing overall flight performance.