The Research And Development Of A Wireless Digital Torque Measurement System

The torque is an important parameter that influences the work of rotating power machinery and the connection of bolts. Torque measurement has become an essential content in the fields of mechanical product development, condition monitoring, fault diagnosis and quality control etc. In this paper, an implementation of hardware and software for a wireless digital torque measurement system was proposed, based on the principle of Wheatstone bridge for measuring torque.According to strain gages' resistance-strain effect, the torque signals were collected by a Wheatstone bridge in this paper. The differences between full-bridge and half-bridge measurements were also analyzed. Moreover, the factors (horizontal effect and paste quality) that affect strain gauge's accuracy were discussed, and the methods of selection as well as sticking of strain gauge were given. In the torque measurement system's hardware, the type and model of key components were selected to meet the principle of low-energy, low-cost and portability. Micro control unit is MSP430FG439, wireless transmission chip is CC2430, and SMG12864G2 is selected as LCD chip. Additionally, the circuits of power module, signal processing module, wireless transmission module and human-computer interaction module were introduced in detail. In the torque measurement system software, the development and debugging environment called Embedded Workbench was described, and the core algorithms, such as signal filtering and calibration, signal storage and signal display, were detailly explained.On the basis of above achievements, a wireless digital torque measurement system was developed, which has the capabilities of torque detection, alarm if torque over threshold, torque data storage and wireless transmission. Finally, the developed torque measuring system was verified by a serious of experiments. Experimental results show that the above capabilities of the torque measuring system are all achieved, and the accuracy of the torque measuring system is±1.1%.