Abstract
A bearingless linear motor(BLLM) which consists of two stators and a common mover is able to levitate and move its mover without any linear bearing or even additive windings. In the previous study, BLLM was actively controlled on the translation and pitch motion, while the roll motion is passively stable. In order to control the roll motion, this paper suggests adding active magnetic bearings(AMBs) at bottom of the mover in BLLM. The AMBs control the roll motion and also partially supports the weight of the mover. In this paper, magnetic forces generated by the AMBs are estimated by using an FEM model. Based on the analysis results, the bias current of the AMBs is determined and a PD controller is designed. Through an experimental levitation test, it was verified that roll motion is well controlled by AMB during levitation.