Non-intrusive torque measurement for rotating shafts using optical sensing of zebra-tapes [dataset]

Non-intrusive, reliable and precise torque measurement is critical to dynamic performance
monitoring, control and condition monitoring of rotating mechanical systems. This paper
presents a novel, contactless torque measurement system consisting of two shaft-mounted
zebra tapes and two optical sensors mounted on stationary rigid supports. Unlike conventional
torque measurement methods, the proposed system does not require costly embedded
sensors or shaft-mounted electronics. Moreover, its non-intrusive nature, adaptable design,
simple installation and low cost make it suitable for a large variety of advanced engineering
applications. Torque measurement is achieved by estimating the shaft twist angle through
analysis of zebra tape pulse train time shifts. This paper presents and compares two signal
processing methods for torque measurement: rising edge detection and cross-correlation. The
performance of the proposed system has been proven experimentally under both static and
variable conditions and both processing approaches show good agreement with reference
measurements from an in-line, invasive torque transducer. Measurement uncertainty has
been estimated according to the ISO GUM (Guide to the expression of uncertainty in
measurement). Type A analysis of experimental data has provided an expanded uncertainty
relative to the system full-scale torque of ±0.30% and ±0.86% for the rising edge and cross-correlation
approaches, respectively. Statistical simulations performed by the Monte Carlo
method have provided, in the worst case, an expanded uncertainty of ±1.19%.