A high force density linear actuator for active suspension

This paper describes a high force density linear electromagnetic actuator for active vehicle suspension. The actuator integrates an 18-slot, 8-pole permanent magnet (PM) machine and a magnetic screw into a single unit to achieve significantly higher force density compared to the design employing linear electromagnetic actuation technology. The leading design parameters of the motor part and the magnetic screw part of the actuator are optimized against a given set of specification. Furthermore, due to the difficulty in manufacturing the helically magnetized magnet pattern, a more practical magnetic screw assembly employing radially magnetized magnet segments is described and its performance assessed. Finite element method (FEM) and analytical technique are employed to assess the actuator performance, and the results are discussed.