Attitude control of satellite with a spherical rotor using two-degree-of-freedom controller

In this paper, we describe a driving principle of a spherical reaction wheel system that we developed for a small satellite. A reaction wheel system has been one of the effective method for a satellite attitude control. However, the attitude control system generally becomes huge and heavy. To overcome this problem, a spherical reaction wheel system was proposed. Although, the system has ability to miniaturize an attitude control system, a driving mechanism for a spherical rotor tends to be huge due to difficulty of three dimensional rotation. In a proposed system, small DC motors are used to drive a spherical rotor to realize a small and lightweight attitude control system. We conduct experiments on attitude control of a satellite model with a spherical rotor by applying two-degree-of-freedom controller.