Design And Implementation Of Inclinometer Based On MEMS Accelerometer Arrav

Geological disasters such as landslides and debris flows are common geological disasters in the world,and they are also secondary disasters of earthquakes or heavy rain.The root cause of this type of disaster is slope instability.The early stage of slope instability is a slow-changing process.Over time,the accumulated internal displacement of the earthwork will exceed the threshold and it will trigger geological disasters.Such disasters often occur in protection and mine operations.The most effective way to prevent such disasters is to monitor long-term changes of small displacements occurring in the earthwork.Based on this assumption,this thesis proposes an inclinometer based on a three-axis MEMS accelerometer array,which can be used in Monitoring of small displacements,and image display of the monitoring situation,early warning of the occurrence of disasters.This thesis proposes that the array oblique meter is based on the function of a single sliding oblique meter,and several independent oblique cells work together through certain communication and connection methods,and realize the long-distance,high-precision automatic monitoring of the internal offset of the soil in a static way.The principle works is that the analog signal of the array MEMS accelerometer is collected by a microcontroller and converted into a digital signal to be finally transmitted to the PC side,and the sensor spatial attitude is resolved by the corresponding algorithm,and the shape of the system is changed by the graph display system.The design system is divided into hardware communication architecture design and software data analysis and optimization algorithm.The communication architecture uses RS485 as the inter-node communication,STM32,16-bit high-precision programmable AD chip,and MEMS accelerometer unit module to achieve intra-node communication.The system is combined with 8 monitoring units with an STM32 single-piece mechanism into a basic group to achieve data acquisition,module conversion and data upload,single or more basic groups can form an array measurement system.In terms of software algorithms,the Kalman filter algorithm is used to estimate the optimal value of the sensor data.Finally,the Euler angle and the conversion matrix are used to resolve the acceleration signal into the sensor space coordinates,and the graphic display is realized with the help of MATLAB.Through testing,the single-section measuring unit of this design system can distinguish the tilt angle up to 0.07°,and the end of the group of 1M length can measure 5mm displacement.The main work content and design ideas of this article are reflected in the following aspects:(1)The system design adopts MEMS acceleration sensor as the detection unit,through STM32 and AD chip cooperates with the unit module,realizes the data acquisition of eight unit modules by one MCU and forms a group as a data node with 8 unit modules;(2)The system communication method is divided into two levels.The upper level uses RS485 to realize the communication between the host computer and the marshalling node unit.The secondary communication structure is the data transmission between the marshalling node and the load unit module.The upper-level communication realizes the mutual data transmission,and the secondary communication structure is to realize the unit control and data collection within the group;(3)A quick calibration method is proposed for the non-orthogonal error,scale factor,and measurement noise error of the system.Kalman filtering is used to filter the noise signal to optimally estimate the continuous output data.Finally,the Euler angle method and the transformation matrix are used to achieve posture analysis.The system status is represented graphically.