On the power system, often need to measure a parameter is rotary torque, in order to measure the size of the rotating torque requires the use of torque sensor. Commonly used to detect the size of the rotating torque testing torsion Angle of phase difference, specific methods are at opposite ends of the elastic axis installation with two sets of teeth, exactly the same shape and installation Angle gear, the outside of the gear installed with a proximity sensor. When the axis rotation, the two groups of sensor can measure the pulse wave, the two groups to compare the two groups of pulse phase difference, and the elastic axis is calculated on the amount of torque. This method is more classic, it can realize non-contact torque signal transmission, detection signal to digital signal, the interference is small; But the volume is bigger, not easy to install and maintain, low speed rotation, the measure is not very precise.

Torque sensor production are now dedicated torsion strain gauge paste on the measured elastic shaft, of the strain bridge, to the power supply strain bridge, can measure the size of the torque. But on the power transfer system, the need to solve a problem is how to make the strain on the body of revolution bridge bridge voltage input and signal output and reliably detect the strain transfer between rotating and stationary part, it's need to use conductive slip ring. Conductive slip ring belongs to friction contact, this creates its own wear, limiting its service life. If because of its contact unreliable, can also cause the error of measurement, make measurements are far from the actual value. In order to make up for the defect of this aspect, can adopt the method of radio telemetry. It is on the axis of rotation torque strain signal amplification and V/F conversion into frequency signal, through the carrier modulation with the method of the radio transmitting fired from the axis of rotation to the axis, with radio reception method, can get axis torsion signal.

Torque by rotating system to produce, if installed on the outside power, wiring is difficult, so the torque sensor generally adopt the battery power. The method for remote sensing torque meter. It overcomes many disadvantages of conductive slip ring, but it also has shortcomings, for example the battery capacity is limited, can only be short term can be used, in addition, it also affected by the interference of electromagnetic environment around, the in the measurement of small range and the occasions of small diameter is more outstanding. The best approach is to use digital torque sensor, which is based on the strain sensor increase two groups of rotating transformer, has realized the transmission of the non-contact energy and signals. It is not affected by rotating speed and the size of the direction of impact, learned the advantages of various methods and overcome its defects, is now measuring the torque of general practice.

Above the paper introduced the development of the torque sensor and the comparison between various types of products, the designers through experiments and summarizes unceasingly, overcomes the drawback of traditional torque measuring methods, inherits the advantages of making torque measurement is more precise, less affected by environment.