Dynamics modeling of three-axis air-bearing table with rotatable appendages

A dynamics model for a three-axis air-bearing table with rotatable appendages is important for ground experiments on the multi-body satellite. Sections 1 through 5 of the full paper explain how we establish the dynamics model. The five sections are entitled respectively: (1) description of the kinematics of the three-axis air-bearing table, (2) the equation for attitude dynamics, (3) the air-bearing table with a number of rotatable appendages, (4) the joining of rotatable appendages to the central rigid-body with gimbals, (5) multi-level joined rotatable appendages. In section 2, we apply the momentum moment theorem. Focusing on the air-bearing table with one rotatable appendage, we did the open-loop dynamics simulation; the simulation results, given in Figs.5 through 8, and their analysis show preliminarily that: (1) the rotation of the rotatable appendage is coupled with the air-bearing table's attitude; without the compensation for the mass centre change caused by the appendage rotation, the gravity unbalance torque will make the experimental results very poor; (2) if the mass centre of the totatable appendage is not along its rotational axis or the rotational centre, additional effects may be exerted on the attitude of the central body.