Design Of Micro Integrated Wireless Strain Test Node

Strain measurement technology is an important test method for researching and analyzing the strength of mechanical structures and the health status of engineering buildings in large-scale industrial equipment.In the fields of offshore oil drilling and aerospace,the structure of equipment is becoming more and more complex.In order to ensure the normal operation of various equipment,strain detection of equipment is one of the essential safety inspection methods.Through the strain detection technology,according to the stress and strain measured by the measured component,to analyze the force of the component,so as to evaluate its bearing performance and reliability.Through the analysis of the existing traditional strain measurement technology,a series of problems brought by the traditional strain test patch,a large number of cable laying,and data transmission are solved.Combine the development of sensor technology and wireless communication technology in recent years,combine sensors with data acquisition and processing,wireless transmission and other technologies.The single-chip microcomputer is designed as the core,the sensor obtains the strain data,and then the operation is processed and stored by the single-chip microcomputer,and then the wireless WIFI communication technology is used to transmit the integrated program.To achieve the system can be reused,the overall miniaturization purposes.The traditional measurement method is to directly paste the resistance strain gauges on the surface of the large components.The method has low operation accuracy,the preparation work takes much time in the early stage,and the interference caused by excessive cables also increases.The elastic member is made of a material having a much smaller elastic modulus than the member to be measured.The strain sensor was designed by attaching the strain gage on the elastic component and attaching the elastic component to the surface of the component under test using bolts.Through the theoretical analysis and finite element analysis of the designed elastic components,the patch placement of the resistance strain gauge was determined according to the stress concentration principle of the sensor design.The theoretical analysis shows that the output of the designed strain sensor has a good linear relationship with the measured one,and has higher sensitivity and measurement accuracy than the traditional strain test.By comparing the same strain measurement experiment with the same component in the same environment to verify the performance of the designed sensor in terms of accuracy and linearity,the static index meets the requirements of general engineering measurement and can be reused.According to the overall scheme of the system design,the wireless strain test node circuit is designed with the single-chip microcomputer as the core.Mainly includes automatic balance bridge,amplification filter circuit,wireless WIFI transmission circuit and power supply circuit.A dedicated program software was used to program the MCU operating software.In view of the direct connection between the amplifier circuit and wireless WIFI data transmission,the node's experimental process in these two aspects is emphasized.The results show that the two main circuit modules meet the requirements of the node.The designed strain test node integrates sensors with data acquisition and processing,wireless transmission and other technologies,which helps to reduce the overall size of the system.The adopted wireless transmission technology not only facilitates the formation of the sensor network,but also avoids a series of problems such as wiring,disassembly,and debugging brought by the traditional wired transmission.At the same time,the design of the elastic sensing element is integrated into the strain acquisition system,which is conducive to improving the test accuracy and reliability.The safety and economy of the strain detection are also significantly improved.