Research On High-precision Multi-channel Strain Measurement System

Strain measurement system is a data acquisition system that can measure the deformation of objects.It is widely used in the fields of aircraft structural strength testing,projectile structural health monitoring,vehicle structural strength testing,ship structural health assessment,and rail health monitoring.Since the measured object is usually very sensitive to strain,and when the deformation exceeds the specified deformation,it will cause a major accident,so improving the strain measurement accuracy is the key research direction of this paper.This paper carries out analysis and research on the strain measurement system based on resistance strain gauges,carries out theoretical analysis and circuit design,provides ideas and references for the field of strain measurement,and has important research significance and practical value.The main research contents of this paper are as follows:(1)The basic principles of resistance strain gauges are studied,the relevant formulas of Wheatstone bridges are derived,and the large resistance self-calibration scheme based on analog switches is proposed for the parameters and performance of the strain measurement system,which is controlled by high-precision DAC.A self-balancing scheme is designed for the reference voltage control method of the operational amplifier of the instrument;a system self-calibration scheme is designed using the DAC to generate a high-precision voltage analog source.In addition,according to the actual requirements of strain measurement,solutions such as bridge matching,signal processing,and bridge excitation are proposed,and related factors affecting measurement accuracy are studied,and corresponding solutions are proposed.(2)Research and analysis on the key technology of the strain measurement system are deeply studied.First,use simulation software Tina-TI and PSpice to model the resistance selfcalibration,self-balance,system self-calibration,signal processing,bridge excitation and other circuits,and then the simulation analysis of AC and DC transmission characteristics is carried out,and finally the parameters of the designed circuit are calculated and deduced.The feasibility of the circuit is verified by the method of combining simulation and calculation.(3)A test platform for the strain measurement system is built,and a test plan is developed.First,the transmission line compensation capability,resistance self-calibration,self-balance,system self-calibration and other functions of the corresponding strain measurement system are tested.Then,the strain measurement accuracy and voltage measurement accuracy are measured in detail,and finally the test results are sorted and analyzed.The test results show that the functions of the high-precision multi-channel strain measurement system designed in this paper are normal,reach the expected indicators,and have engineering practical value.