Magnetostrictive Torque Sensors - Comparison of Branch, Cross, and Solenoidal Designs

Intense worldwide activity is currently focused on development of magnetostrictive torque sensors. The sensors are both non-contact and provide high sensitivity in combination with robustness. They are therefore prime candidates for use in torque-feedback closed-loop controls of automotive engines and transmissions.

Previously, both linear and nonlinear analyses of the branch-design of magnetostrictive torque sensors were given. This paper goes beyond prior work to include cross-design and solenoidal-design sensors (designs that are more commonly used).

For each sensor design: general models are derived, equivalent electrical and magnetic circuits are developed, and equations governing signal outputs are given. A comparison is done of magnetic circuit operating behavior for sensors designed to fit into the same space on a shaft made of maraging steel.