1 STIFF TORQUE TRANSDUCER WITH HIGH OVERLOAD CAPABILITY AND DIRECT FREQUENCY OUTPUT

A new torque transducer with high overload capability and direct frequency output is reported. It employs the recently developed metallic triple-beam resonators with thick-film printed lead zirconate titanate (PZT) drive and pickup elements. The new torque transducer has been tested in a torque range of up to 20 Nm, resulting in a strain level of 400 microstrain on the measurement shaft surface and giving a large frequency-change output of 800 Hz. The strain level required by the new torque transducer can be much lower (~100 microstrain) than the level (~1800 microstrain) usually required by conventional metallic resistance-strain-gauge-based torque transducers, thus increasing the transducer overload capability by a large factor. Nevertheless, under such a low strain level, the new torque transducer can still output an adequately large frequency change of 200 Hz for measurement. Having a large overload capability is very important in many torque measurement applications where rapid and large overloads can occur