Modeling and control of a high-thrust direct-drive spiral motor

Abstract

In this paper, modeling and control of spiral motor is proposed. The voltage equation and motion equation of the spiral motor is proposed. Based on this modeling, control system for the spiral motor is proposed. The proposed controller consists of three parts; the first part is PI current controller with back EMF compensation specialized for spiral motor, the second part is disturbance observer based PD controller for linear and gap motion interacting each other, and the third part is zero-power controller for equilibrium fluctuation of gap displacement. It is confirmed that the proposed controller achieves independent linear position and gap control simultaneously.

Zero Power Control Based on External Force Feedback for Helical Motor

“…A motion equation of a helical motor is derived from a magnetic circuit of the motor (5) . From the report (5) , thrust-force and torque in the forward side and the backward side are described as (2)- (3) and (4)- (5), respectively.…”

“…From the report (5) , thrust-force and torque in the forward side and the backward side are described as (2)- (3) and (4)- (5), respectively. In the equations, a magnetic resistance of mover yoke is neglected.…”

“…A gap controller is applied to achieve magnetic levitation of the mover (5) . This controller consists of a PD-control, and generates a gap acceleration referenceẍ ref g as a follow.…”

“…(17) is a linear acceleration reference of this position controller (5) , the reference is calculated based on a PD-control law.…”

“…For conventional approaches, it is difficult to realize a compact motor which achieves high torque/force and high back-drivablity. Therefore, the authors have proposed a new linear motor called Helical motor (5) . Helical motor consists of a helical mover and stator.…”