Research And Engineering Application Of MEMS Inertial Measurement Technology

Deep displacement monitoring is widely used in slopes,road subsidence,deformation of dam panels,and urban foundation pit monitoring.The internal movement of rock and soil has always been a problem that plagues the engineering community,regardless of natural disasters such as landslides,ground subsidence,deformation of dam face plates,and dam body settlement and other practical engineering problems.Accurate monitoring methods are the necessary foundation for other work.The domestic deep displacement monitoring methods and instruments are mainly from foreign countries.The research and development of domestic instruments is slow and the accuracy is low.Therefore,it is of great engineering significance for the research and development of new instruments and the improvement of accuracy.At present,the deep displacement measuring device represented by the flexible array displacement meter(SAA)produced by Measurand,Canada,can measure the internal deformation of the rock and soil in real time,and has the advantages of automation,intelligence and high precision.It has been applied in various projects and slopes at home and abroad,and achieved good results.However,this product is expensive,difficult to maintain,and difficult to promote and apply in China.Therefore,drawing on domestic and foreign design experience and engineering application requirements,the author’s team,under the leadership of the instructor,carried out independent research and development of two sets of flexible displacement meters based on MEMS(micro mechanical system)inertial sensing technology and micro inertial trajectory measurement system to improve accuracy,The work of applied research.The main contents are:(1)Error analysis of the flexible displacement meter,including structural error analysis,to compensate for the influence of the deformation of the flexible joint.Research the method of the flexible displacement meter to distinguish the direction of displacement and deformation.It can identify whether the installation of the flexible displacement meter has problems or not through the measurement data,and identify the direction of the displacement of the rock and soil.(2)Perform error analysis on the core sensor MEMS accelerometer used in both systems.Error sources are mainly divided into static error,random error,and temperature drift.For static error calibration,a twelve position calibration method based on particle swarm optimization algorithm is proposed to find zero offset,three-axis non-orthogonal coefficients,and calibration error.It has the advantages of higher accuracy and faster speed.Through the ring installation experiment,test the accuracy of the flexible displacement meter in a large range of angle changes.(3)Aiming at the micro-inertial monitoring system,using the combination of LabVIEW and MATLAB,a PC-side processing software integrating signal processing,accelerometer calibration,deflection curve output,data management and other functions has been developed.For the flexible displacement meter,a system software integrating signal filtering,accelerometer angle value,displacement calculation,and two-dimensional and threedimensional images has been developed.(4)Apply micro-inertial sensors to the Jiangping River face rockfill dam,and conduct comprehensive monitoring from the second-stage faceplate construction period to the complete pouring of the dam faceplate.The measurement data is calculated and the monitoring results are analyzed and compared.It can be seen from the panel deflection curve that the measurement results have good repeatability.A comparison with the fiber optic gyroscope system proves its reliability.The panel deformation law conforms to the objective law.