A low-complexity rotary-linear motor useable for actuation of active wheels

The combination of a rotary and linear motion along the same axis is used in several applications, including tooling machines, robotics, automation etc. It may be also used to conveniently manage pairs of basic functions of active wheels in electric and hybrid vehicles. In such cases, rotary-linear machines may represent an interesting alternative to the usual employ of a separated actuator per each basic motion. Anyway, such machines often rely on a structure that is either not suited to be conveniently realized using common materials and manufacturing techniques, or exhibits a complex behavior not permitting an effective decoupled control of force and torque. This paper presents some results concerning the structure, theoretical modeling, FEM analysis, magnetic circuit modeling and drive control for an isotropic brushless machine recently proposed.