Design Optimization and Test of a Radially Magnetized Magnetic Screw With Discretized PMs

A magnetic screw is a new type of high force density linear actuator. One of the key challenges for realization of the magnetic screw concept is the manufacturing process of its helical permanent-magnet (PM) poles. Structure simplification and simple assembly process are essential in promoting the development of the magnetic screw. This paper studies several PM configurations employed to realize the magnetic screw and proposes a new structure, which can well approximate the helical magnetic poles in a very simple way. The electromagnetic performances are assessed analytically and by time-stepping finite-element analysis (FEA). Finally, both the analytical model and the FE results are validated by experiments based on a prototype machine.