Abstract
The three-dimensional reaction wheel (3DRW) is a three-axis free rotor reaction wheel, which can achieve a compact and high integrity attitude control systems. In the system we propose, a spherical rotor is levitated without mechanical contact by gas bearings and rotated by the torque generated by magnetic fields. To realize the precise control of the rotor, it is important to understand the characteristics of spherical gas bearings such as pressure distribution, load capacity, stiffness and flow rate. Some previous works clarified them but few researches are there relating the use of gas bearings in the space. What is required for the space gas bearing is having the minimum robust characteristic against various small disturbances. It is more appropriate to adopt small-light air compressor which can provide the minimum air pressure and flow than big-heavy powerful one. In this study, the authors have developed a spherical gas bearing with a circular slot restrictor and analyzed its performance by experiments and numerical calculations. The result shows that this type of bearing can generate necessary floating force with low supply pressure and low flow rate, and that leaves the possibility to realize 3DRW system operated by a compact pump such as piezoelectric type.
