A Study And Design On MEMS Accelerometer-Based Inclination Sensors For Bridge Deformation Monitoring

Collapse accidents caused by aging and damage of bridge structures frequently occur all over the world.Structural health monitoring(SHM)is an effective monitoring technology,which can greatly reduce the damage caused by bridge collapse accidents and even avoid many unnecessary bridge accidents.Bridge deformation monitoring is an important part of bridge structure health monitoring,because the deformation of the bridge not only reflects the structural safety characteristics such as the stiffness,bearing capacity and integrity of the bridge structure,but also is closely related to the operational performance such as pedestrian and driving comfort.Because the successful monitoring work is based on the sensor accurately sensing and transmitting data signals,many researchers try to apply the MEMS accelerometer which is made by MEMS(Micro-Electro-Mechanical-System)technology and has the advantages of low cost,small size,high durability,low power consumption and easy installation.In order to explore the application prospects of MEMS accelerometers in structural deformation monitoring,this paper studies the deformation monitoring work using MEMS accelerometerbased inclination sensors.The main work and results are as follows:(1)Discusses the significance and necessity of bridge structure health monitoring,and describes the development and application of monitoring sensors in bridge structure health monitoring.The eight common methods of bridge deformation monitoring are discussed and analyzed in detail,and the characteristics and advantages of the inclination method are compared and discussed.The development research of MEMS acceleration sensor in structural health monitoring is introduced,and the research status of MEMS acceleration sensor error calibration method is summarized.(2)Introduce the working principles of three commonly used acceleration sensors and summarize an acceleration sensor selection method.Introduced the inclination method based on MEMS accelerometers-based inclination sensor and its theory and the method of solving the conversion relationship between the inclination angle deformation and other deformations by applying mechanics theory method or function interpolation method.In the research of dynamic deformation monitoring based on MEMS accelerometer-based inclination sensor and inclination method,this study elaborated the error source of the dynamic deformation monitoring results and proposed an algorithm different from the traditional signal filtering processing method to reduce the additional acceleration's error effect.(3)The development tool of MEMS accelerometer-based inclination sensor is introduced,and the four modules(acceleration sensor module,wireless sensor module,microprocessor module and energy supply module)of the ADXL355 MEMS accelerometer-based inclination are elaborated in detail Hardware design work.Completed the schematic design of the ADXL355 MEMS accelerometer-based inclination and used the Altium Designer development and design platform to complete the corresponding printed circuit board design.(4)The error source of the MEMS accelerometer-based inclination is analyzed in detail and an improved calibration technique is proposed.In this technology,a single-parameter mathematical model is constructed to directly calibrate the relative inclination and a method based on image processing technology is designed to obtain key calibration parameters in the mathematical model,so that the calibration technology can be used in field testing operating.Compared with the traditional six-parameter calibration method,the improved calibration technique has the following advantages: the technique is easy to implement,only one calibration parameter needs to be solved but does not affect the accuracy of the calibration result;the calibration setup is simple,and does not involve complex instruments.(5)Three experiments were carried out to achieve the following objectives: evaluate the feasibility of the improved calibration technique;evaluate the deformation monitoring effect of the MEMS accelerometer-based inclination sensor designed in this study and the improved calibration technique;test the feasibility of the dynamic inclination monitoring algorithm based on the MEMS accelerometer-based inclination sensor proposed in this study.Experiments show that the improved calibration technique proposed in this research can significantly reduce the proportional error effect in the inclination monitoring value;when the MEMS accelerometerbased inclination designed in this paper is used with the improved calibration technique,its working performance can meet the engineering requirements;The proposed dynamic inclination monitoring algorithm based on MEMS accelerometer-based inclination sensors can effectively reduce the error effect of additional acceleration on the inclination monitoring value.