Dynamic rotary torque measurement Using surface acoustic waves

The subject of torque measurement has previously been addressed extensively. Most of the existing transducers either rely on low voltage analogue systems (e.g. conventional resistive strain gauge) or complicated mechanical assemblies by physically assessing displacement, i.e. optical systems. This paper identifies a new, potentially low cost, non-contact, frequency domain strain torque sensor1 utilising SAW (Surface Acoustic Wave) Technology for surface strain measurement. The sensor has a short axial length making it flexible in terms of integration into a variety of applications, encompassing both static and dynamic measurement. The paper presents a technical description of the resulting transducer, regarding its operation and construction.