OPTICAL TORQUE SENSOR DESIGN ENABLES NEW OPPORTUNITIES FOR MACHINERY DIAGNOSTICS AND FAILURE PREVENTION

摘要

Commercial torque transducers are available today and widely used for industrial and commercial applications such as web process lines and vehicle test stands. While currently available sensor provide torque information for process monitoring and control their use is frequently limited to high-value or critical applications due to the cost, size, reliability and performance limitations of commercial torque sensors. We have previously demonstrated a non-contact optical torque sensor that employs a low cost light source, photo-detector and a photoelastic element. As a polarized light beam is transmitted through the strained photoelastic element the exiting beam exhibits a phase shift in the direction of principal strains and a birefringence pattern appears when viewed through a polarizing filter that is characteristic of the material deformation. When the photoelastic material is attached to a power transmission shaft, this phase shift can be quantified and is directly related to the torsional load on the shaft. This paper presents the operating principle of the optical torque sensor along with several enhancements that provide for increased accuracy, self-powered operation, and remotely located electronics and active optical elements. These enhancements provide unique opportunities for machinery health assessment and failure prevention.