Development of spherical motor (2nd report, Rotor posture detection and feed-back control)

Abstract

Spherical motor is a multi-degrees of freedom actuator which can be rotated in various directions. However, the control method of the completely arbitrary direction was not fully established in the conventional research. This study develops a controlling method of a spherical motor that can rotate to all directions and can be fixed to arbitrary postures. In the 1st. report, the torque generating method to the arbitrary directions from arbitrary rotor postures that used a torque-map was shown. However, in order to generate the torque towards the desired direction from arbitrary postures and to stop with a target posture, monitoring of the present rotor posture is indispensable. In this report, the rotor posture detecting system using the information of two optical mouse sensors is shown. The detection technique of the rotor posture using the information from the sensors installed in the arbitrary position is described in detail. The experimental results of the mouse sensor system are shown. Based on this current rotor posture and the target posture, the feedback control algorithm that can position the rotor into the target posture is also explained. And experimental results of the feedback control are shown. The experiment shows that the rotor can be moved and positioned to the target posture by using the feedback control.