Control of a Two-Body Precision Turntable Electromechanical System in the Presence of Friction*

Control of an electromechanical system consisting of two rigid bodies connected to each other through a direct high-torque electric drive is considered taking into account small frictional perturbations. Both bodies rotate around a common axis. The voltage applied across armature-circuit terminals of the motor serves as a control variable. The system under consideration is a simplified model of the precision turntable mounted on the orbiting spacecraft and is designed to reduce the apparent acceleration of the container with a payload. The discussed dynamical model takes into account the friction torque in rolling bearings with respect to the rotation axis. A control law is proposed, which, for sufficiently small friction and disturbances, in a finite time interval provides a predetermined motion of the second body relative to the first one.