Designs for 2000 Nm Intelligent Torque Sensor
|School||Shanghai Jiaotong University|
|Keywords||intelligent sensor strain gauge instrumentation OP amplifier torque|
Torque measurement has very broad application fields, which include air-plane, warship, artesian well, power supply station devices and metallurgy devices etc. with great torque, which also include micro motor, appliance and watch hairspring etc. with small torque. The primary purpose of developing 2000 Nm intelligent torque sensor is in order to enhance the measurement precision, and meet the requirement of inter-comparison and traceability for torque standards.This paper describes the working principle and mechanical analysis model of strain gauge torque sensor. After establishing three-dimensional solid model of elastic body, the position and orientation the strain gauges pasted is determined by ANSYS finite element analysis.Signal conditioning circuit embedded within the sensor adopts instrumentation OP amplifier which has high CMRR and high input impedance to amplify mV level of the sensor output. The microprocessor PIC18F2458 is the core part of the circuit. The 24-bits ADC which has self calibration, zero calibration, full-scale calibration and GPA etc. intelligent functions converts the analog signal to digitals. The microprocessor normalizes this digital, then the conditioning circuit outputs a strong anti-interference (4-20) mA standard signal by a DAC. There are several digital temperature sensors in the built-in conditioning circuit, which monitors the inner temperature of the intelligent sensor as shift compensation. This paper describes how to realize the USB communication interface firmware development and host software design through this built-in USB module. After 2000 Nm Intelligent torque sensor manufactured, a variety of experiments are carried out to validate the desired technical specifications. This paper takes uncertainty analysis for the experimental data. The result indicates the technical specifications meet the design requirements.