Development of a Magnetoelastic Torque Sensor for Formula 1 and CHAMP Car Racing Applications

The benefits of a magnetoelastic torque sensing system and its application on Formula 1 and CHAMP Car racing driveshafts are identified. In particular, the use of circumferential remanent magnetic bands on the shaft itself has enabled a design that satisfies the application's demanding packaging requirements. The criteria used to determine the suitability of a given shaft material for optimal magnetoelastic characteristics and concurrent mechanical strength are illustrated. Shaft material and geometry are shown to have significant effects on sensor performance. Design considerations for the magnetic field sensor layout and signal conditioning circuit are also presented. The racing driveshaft application is shown to add particular challenges in terms of temperature, packaging, and kinematic tracking. Magnetization and calibration processes associated with field operation of the sensor are discussed. Selected results from extensive track testing with Stewart-Ford in Formula 1 and Visteon-Patrick Racing in CART are presented and analyzed. Successful development and implementation of the racing torque sensor as a basis for extension to mass production automotive applications is suggested.