Time Quasi-Optimal Deceleration of Rotations of a Gyrostat with a Moving Mass in a Resistive Medium

The problem of time quasi-optimal deceleration of the rotations of a rigid body that includes elements with distributed and lumped parameters is studied. It is assumed that the body contains a spherical cavity filled with a highly viscous fluid (at small Reynolds numbers) and a viscoelastic element that is modeled by a moving mass connected to the body by a strong damper. The moving mass models loosely attached elements in a space vehicle, which can significantly affect the vehicle’s motion relative to its center of mass during a long period of time. In addition, the body is affected by a small medium resistance torque and a small control torque localized in a ellipsoidal domain. The problem is solved asymptotically based on the procedure of averaging the unperturbed precession over the phase. A numerical solution is obtained.