Design of a Low-Cost Air Bearing Testbed for Nano CMG Maneuvers

In this paper, a low-cost, miniature spacecraft attitude control simulator is presented for testing miniature actuators such as Nano Control Moment Gyroscopes (CMGs) for simple maneuvers. The experimental setup is composed by an attitude control system (ACS) that mainly consists of a four-CMG cluster in a pyramid configuration and a custom-made air bearing. The one-degree-of-freedom (DoF) air bearing is fabricated to reproduce the frictionless conditions of a nano-satellite in orbit. The ACS is made exclusively using low-cost commercial-off-the-shelf (COTS) components, whilst the air bearing is made using 3D-printed parts. Both hardware and software implementations are described in detail and the performance of the developed simulator is evaluated by two maneuver experiments. Despite the manufacturing imperfections, the ACS is capable of providing higher angular velocities than previously presented in the literature while following the theoretical or simulation data. The results indicate that it is possible to manufacture a low-cost, miniature actuator such as a CMG, using COTS components to demonstrate the operation of an agile nano-satellite. Any deviations from the theoretical values are addressed and several improvements are discussed to further enhance the performance of the air bearing testing platform.