Research On Integrated Piezoelectric Torque Dynamometer

In order to improve the development level of the manufacturing industry,relevant departments have planned an important action plan for "Made in China 2025".Among them,intelligent manufacturing is an important measure in the action plan.In the field of intelligent manufacturing,intelligent machine tools for real-time torque monitoring are extremely important.Therefore,the development of integrated torque dynamometers for practical applications is of great significance for maintaining product quality,promoting manufacturing efficiency,ensuring processing accuracy,and reducing production costs.In response to the need for intelligent torque monitoring in the machining process,an integrated piezoelectric torque dynamometer was designed.The torque dynamometer studied in this paper has completed the mechanical structure design,the embedded hardware circuit design and the upper computer software design.The main contents of the research are as follows:(1)In order to realize the real-time monitoring of the torque signal,an integrated piezoelectric torque dynamometer was designed.This paper has carried out the research of the measurement scheme,involving the arrangement of piezoelectric sensor unit and the calculation of the size of the quartz wafer.Combining the above measurement schemes,the design of the mechanical structure of the torque dynamometer and the construction of the three-dimensional model have been completed,and the strength of the main structure of the dynamometer has been checked.Furthermore,the finite element simulation software is used to conduct static and modal simulation analysis on the three-dimensional model of the dynamometer,optimize and determine the structural parameters of the dynamometer,and verify the rationality and reliability of the structural design of the torque dynamometer.(2)Based on the completion of the structural design of the integrated piezoelectric torque dynamometer,the embedded hardware circuit of the dynamometer was designed.The embedded hardware circuit includes signal conditioning circuit,analog-to-digital conversion/wireless transmission circuit and power supply circuit.The signal conditioning circuit is composed of a charge conversion stage circuit,a voltage-controlled voltage source second-order low-pass filter circuit,a normalization circuit and an output amplifier stage circuit,which can convert the weak charge signal into an amplified voltage signal without distortion.The analog-to-digital conversion/wireless transmission circuit uses the analog-to-digital converter in the STM32 single-chip microcomputer to realize the conversion of analog signals to digital signals,and the converted digital signals are sent by the WIFI communication module in real time.The power supply circuit is composed of a conductive slip ring and a DC-DC step-down module.After the electrical energy is input from the conductive slip ring,it enters the DC-DC step-down module,and is uniformly processed into a suitable voltage to supply power to other circuit boards.(3)A real-time torque monitoring assistant is developed based on Lab VIEW software.The WIFI communication method is adopted to realize the real-time data collection during the cutting process,and the collected data is displayed in real time on the instrument and the waveform diagram.The received data can be saved as a text format file with one key.When the received data exceeds the set threshold,the software alarm mechanism will be activated and feedback to the operator in the form of an alarm indicator and an alarm sound.(4)The built-in signal conditioning circuit and the domestic standard charge amplifier are used to carry out comparative calibration experiments.The non-linear error and repeatability error of the signal conditioning circuit obtained in the experiment are both lower than 0.1%,and the calibration data is relatively close to the calibration data of the domestic standard charge amplifier.Assemble the mechanical parts of the torque dynamometer,and install the relevant embedded hardware circuits to complete the overall static and dynamic calibration experiments of the dynamometer.The experimental results show that the overall nonlinear error and repeatability error of the dynamometer are less than 1%,and the natural frequency of the dynamometer is 321.04 Hz,which meets the design requirements.