Applying fiber-optic system to control shaft torque

The article considers the procedure of torque control, which is very popular in a wide variety of industries with many design features. In marine power engineering the problems of determining the forces, torque on the shaft and power are solved by means of torsiometers with torque sensors. The most widely used torque sensors are of capacitive, induction, strain gauge and photoelectric types. It has been stated that there are limitations in the process of torque control due to the susceptibility of systems to the electromagnetic interference, lack of a high degree of protection for electrical equipment and necessary recalibration. Fiber optic systems have found application in torque measurement systems in the oil and gas and aerospace industries. The use of such systems on ships is more expensive in comparison with the technologies used today, for example, the systems based on strain gauges. It has been proposed to use an inexpensive optical measuring system based on the Pound-Drever-Hall technique with using a foil-clad strain gauge and an aluminum torsion rod. There has been illustrated the system of torque control, the phase graphs for the Fabry-Perot resonator and the graph of the resonator transmission spectrum are presented, the reflection coefficient value is given. A method for measuring the phase of a reflected beam from a Fabry-Perot resonator is being considered, the injection current of a laser is modulated by means of an electric oscillator to generate side stripes in the electric field of a laser beam. The carried out studies and calculations contribute to improving the reliability of the coastal power system; the possibility of their use in marine electrical systems has been proved.