Research On Ring Type Torque Sensor Based On Magnetoelastic Effect Of Amorphous Alloy

Torque is an important performance index, which reflects the performances of equipment. O ne of the important development directions of the torque sensor is that achieving non-contact measurement of the rotation and dynamic conditions. The principles and methods of measuring torque are various. And torque measurement principle based on magnetic bomb has many advantages, such as non-contact and good dynamic characteristics. So the magnetoelastic effect is widely used in the sensor. In recent years, the development of new materials is fast, such as amorphous alloy and nano crystalline alloy, whoes magnetic properties are very good. After been been applied to the sensor, they have greatly promoted the great progress of the sensor.The main research of this paper is divided into theoretical research and experimental part. The main research contents are as follows. First the basic properties of amorphous alloy are introduced in this paper, including electrical properties, chemical properties, mechanical properties and magnetic properties. Then measurement principle of amorphous alloy is analyzed. Fe based amorphous alloy is selected as the sensitive material of the sensor. And the bonding method is used to attach the amorphous strip to the rotating shaft. Last principles of several common torque sensors are analyzed, and advantages and disadvantages are compared. The test part includes two parts, one is the design of the sensor structure, the software and hardware, another is the experimental verification. The structure of the sensor and the design of hardware and software are as follows. The sensor structure is identified as a ring type, multiple-probe, differential and noncontacting type. Fe amorphous alloy is selected as the sensitive material, which is attached onto the shaft by pasting method. The structure and working principle are elaborately introduced. And the most suitable parameters including number of turns, e xcitation current, frequency and so on are identified through repeated tests and careful calculation. Testing system of the sensor is designed, including signal generation, measurement circuit, NI cDAQ data acquisition system and data processing part written by Lab VIEW. The circuit section includes an alternating current bridge, an amplifier, an oscillator, a detector, and a filter, and so forth. CompactDAQ case and USB-9215 acquisition Card which produced by National Instruments Corporation are adopted for the reason of acquisition accuracy. Software platform used for Data analysis and processing is written by Lab VIEW. The front panel is very concise and easy to operate. The test verification part is as follows. Linearity, sensitivity, repeatability, hysteresis and other static performance indicators are identified by repeated tests on the special devices and the analysis of data. And finally the reasons of errors are analyzed.This topic shows that the output signal of the sensor is strong, and the accuracy is very satisfactory after Fe based amorphous alloys been applied to torque sensor. So the piezomagnetic effect of amorphous alloys can be applied to torque sensor perfectly. It is can be seen that a fter the further optimization and design improving, this topic will finally be applied to a variety of actual measurements.