Design And Research Of Angle Measuring Torque Wrench Based On Torque Angle Method

The reliability of bolted joints is critical due to the accidents often caused by the failure of threaded fasteners.It is important to design a high accuracy and low-cost torque wrench based on the torque angle method(TAM here after)since which not only has higher accuracy and better reliability compared with the torque control method,but also solve the problem of low control accuracy of domestic torque wrenches and expensive of foreign ones.This thesis presents a design of a torque wrench based on TAM by comparing bolt tightening methods and analyzing similar products in the market.The software and hardware design were completed under the design principles of low power consumption,portability,low cost,anti-interference and high accuracy.It was connected to IOT via Bluetooth and WIFI communication module.The communication subroutine was carried out for Android mobile and PC terminal to realize wrench monitoring,data exchange and analysis.The system selects low-power STM32L431RCT6 and controllable power supply to reduce system power consumption,designs U/I and data storage functions to enhance user experience,uses the resistive strain gauges to complete torque measurement,and the MPU9250 to complete angle data acquisition,uses algorithms such as Kalman filter and complementary filter to reduce the random wandering and zero-point drift of the gyroscope and reduce the error generated during measurement to improve the accuracy of measurement.Experiments have verified that the measurement scheme is feasible and has good data processing effect,connection with mobile and PC terminal is successful and realizes data transfer and command control,the designed wrench meets the design requirements and the original design intention,and with high control accuracy to satisfy the needs of complex scenarios use.