Design of a Normal Stress Electromagnetic Fast Linear Actuator

This paper describes the design of a normal stress electromagnetic linear actuator for fast tool servos during nonrotationally symmetric diamond turning. By using the permanent magnet as the biasing flux generator and the total armature pole surface for force generation, the actuator is designed to achieve both linear operation characteristics and high acceleration. A design methodology is presented, which is based on analytical and finite element method magnetic circuit analysis. For design optimization, a new criterion, high actuating force density, is introduced. Based on the optimized structural parameters and the strategy of design for manufacturing, a novel axisymmetric fast linear actuator is developed that has a stroke of 100 $\mu{\hbox{m}}$ and 500 G acceleration. The linearity of the actuating force versus both the excitation current and the armature displacement is experimentally demonstrated. It is shown that the experimental and calculated results agree well with each other.