| Dynamic modeling of the atmospheric flight mechanics of a projectile equipped with an uncontrolled internal rotating disk is investigated and a modified projectile linear theory is established. It is shown through modeling of this type of projectile that several coefficients of the epicyclic dynamics are altered, leading to changes in the fast and slow epicyclic modes. A study of the frequency and damping properties of the epicyclic modes is conducted by systematically varying disk orientation, location, mass, and rotational speed. It is shown that the presence of an internal rotating disk can cause substantial changes in the epicyclic dynamics, suggesting the potential of a rotating internal part as a possible control mechanism. A further study considers the active trajectory control of a projectile using a mass unbalance, created by the radial orientation of an internal part. To evaluate the potential of this concept, a seven degree-of-freedom flight dynamic model of a projectile equipped with an internal part is defined. It is shown that by holding the internal part fixed with respect to a non-rolling reference frame, predictable trajectory changes are generated including predictable impact point changes. It is also shown that using the same control mechanism and destabilizing the projectile by fundamentally altering the inertia and, or aerodynamic properties of the projectile can lead to greater control authority. |
