Abstract
The interest and effort invested in developing a motor with multiple degrees of freedom (DOF), which by itself can directly drive motion in multiple directions simultaneously, are increasing. Such motors are intended for use in industrial applications having increasing complexity and performance demands. Active research is being conducted on linear motors with two DOF, driving linear and rotational motion simultaneously, for application in multiple-DOF positioning systems. We aim to develop a medium-sized rotary-linear motor (RLM) with a few or more kilowatts power and with capacity for rotational and translational motion. Here, we present a method for installing a salient pole on a needle with magnets, which can enable the use of soft magnetic materials with low eddy-current loss as the iron cores. We demonstrate the installation method for a salient pole that generates reluctance electromagnetic forces in one or both directions: rotational and translational. This study demonstrates the effectiveness of the salient pole in increasing the electromagnetic force. We also introduce a mathematical model of RLM with a salient pole on a dq coordinate system. The model is used to explain the interactive magnetic interference generated by the armature currents for rotational and translation motion. A test motor is used to verify the effect of the salient pole, estimate the eddy-current loss, and examine the spiral motion due to the rotational and translation motion.
