A dynamic torque sensor is an electronic measurement device used to measure and record torque variations in rotating or dynamically moving mechanical systems.[1] As compared to static torque sensors, which measure torque when the object is stationary, dynamic torque sensors specifically measure rapid fluctuations.[2] They report torque variations in real time.[3]
These sensors are used where control and monitoring of torque are required, and they play a role in operational safety.[4] They help determine the efficiency of mechanical components such as motors, drive shafts, and rotating equipment.[5]
A dynamic torque sensor uses measurement principles such as strain gauge technology, magnetoelastic effects, optical sensing, and piezoelectric effects.[6][7][9]
Strain gauge technology
Strain gauge deformation under tension (left) and compression (right)
Strain gaugesdeform when torque is applied. This results in change in electrical resistance proportional to the torque, allowing the measurement of strain. These sensors claim an accuracy of ±0.3 % of full scale in laboratory tests and are commonly integrated into measurement rigs.[6]
Magnetoelastic effects
These sensors use changes in magnetic properties when torque is applied. The magnetoelastic principle enables non-contact torque measurement. Manufacturers report that magnetoelastic sensors can operate in high-temperature or high-vibration conditions with minimal maintenance.[7]
Optical sensing
Optical torque sensors utilize light-based techniques, namely interferometry or phase shift measurements, to detect torque. They provide high sensitivity, immunity to electromagnetic interference, and minimal mechanical interference.[8]
A dynamic torque sensor can be classified according to its sensing technology and application.
Firstly, rotary torque sensors measure torque on rotating shafts. They use strain gauges or magnetoelastic technology and are used in engines, gearboxes, and drive shafts.[17]
Secondly, non-contact torque sensors measure torque without physical contact. They use magnetoelastic or optical techniques thus reducing wear and maintenance requirements. They are especially helpful in harsh or high-speed environments.[18]
Lastly, reaction torque sensors use strain gauge technology and are engineered to measure torque without rotation. They are used in torque testing benches and component validation setups.[19]
Industrial automation and robotics uses them in monitoring torque in robotic joints, industrial machinery, and automation systems. Studies have shown that torque monitoring can detect abnormal loads in robotic joints, potentially preventing failures.[15][16]
Technical specifications and performance criteria
Dynamic torque sensors are distinguished by their technical specifications and performance criteria. They are then accordingly considered suitable for specific applications:
Sensitivity: small changes in torque are detected by sensor.
Accuracy: degree to which sensor measurements reflect true torque values.
Resolution: smallest detectable increase in torque.
Frequency response: range of frequencies over which the sensor accurately measures dynamic torque.
Temperature stability: accurate measurements maintained by sensor across varying temperatures.
Proper calibration and maintenance of dynamic torque sensors is vital to guarantee their accuracy over time.[23] Both static and dynamic calibration methods are included to maintain sensor accuracy. Furthermore, compliance to recognized calibration standards, such as ISO and ASTM would ensure consistency across measurements. Regular inspection, cleaning, recalibration, and proper handling is also crucial to extend the lifespan of the sensor.[24]
^ abcHammond, J. M., & Lec, R. M. (1998, May). A non-contact piezoelectric torque sensor. In Proceedings of the 1998 IEEE International Frequency Control Symposium (Cat. No. 98CH36165) (pp. 715-723). IEEE.
^ abLee, T. H., Low, T. S., Tseng, K. J., & Lim, H. K. (2004). An intelligent indirect dynamic torque sensor for permanent magnet brushless DC drives. IEEE Transactions on Industrial Electronics, 41(2), 191-200.
^ abKang, H. S., & Meneveau, C. (2010). Direct mechanical torque sensor for model wind turbines. Measurement Science and Technology, 21(10), 105206.
^ abZhang, Z., Zhao, Y., Qiao, W., & Qu, L. (2015). A discrete-time direct torque control for direct-drive PMSG-based wind energy conversion systems. IEEE Transactions on Industry Applications, 51(4), 3504-3514.
^Beck, J. (2021, April). Torque sensors for high volume production applications. In CTI SYMPOSIUM 2019: 18th International Congress and Expo 9-12 December 2019, Berlin, Germany (pp. 17-24). Berlin, Heidelberg: Springer Berlin Heidelberg.
^Palli, G. I. A. N. L. U. C. A., & Pirozzi, S. (2013). An optical torque sensor for robotic applications. International Journal of Optomechatronics, 7(4), 263-282.
^ abTsetserukou, D., & Tachi, S. (2008). Torque sensors for robot joint control. Sensors, Focus on Tactile, Force and Stress Sensors, 15-36.
^ abLi, Z., Li, X., Lin, J., Pang, Y., Yang, D., Zhong, L., & Guo, J. (2023). Design and application of multidimensional force/torque sensors in surgical robots: A review. IEEE Sensors Journal, 23(12), 12441-12454.
^Morsy, W. (2024). Fabrication of a rotating shaft torque sensor for power data determination of rotary farm implements. Alexandria Journal of Soil and Water Sciences, 8(1), 49-56.
^Zhang, C., Li, Z., Chen, J., Qiu, F., & Na, S. (2021). Design and research of a novel non-contact vertical inductive torque sensor. Measurement, 177, 109252.
^Muftah, M. H., Haris, S. M., Petroczki, K., & Khidir, E. A. (2013). An improved strain gauge-based dynamic torque measurement method. International Journal of Circuits, Systems and Signal Processing, 7(1), 66-73.
^Persson, O., & Persson, G. (2015). Torque Sensor for Automotive Applications. CODEN: LUTEDX/TEIE.
^Albers, A., Fischer, J., Behrendt, M., & Lieske, D. (2015). Methods for measuring, analyzing and predicting the dynamic torque of an electric drive used in an automotive drivetrain. SAE International Journal of Alternative Powertrains, 4(2), 363-369.
^Cheng, L., Su, Y., & Wang, L. (2021, December). Research on the Calibration Method of Torque Sensor. In Journal of Physics: Conference Series (Vol. 2136, No. 1, p. 012004). IOP Publishing.
