The Flume-debris Flow Experimental Boulder Migration Attitude Detection System Design

During the outburst of debris flowing,the main source of its destructive power is the collision caused by the boulders wrapped in slurry.Many geologists observed the start-up and migration of boulders by the flume experiments.They believed that the start-up and migration patterns of boulders are directly related to debris flows.Although these studies have corresponding theoretical models,they lack the support of the actual measurement data of boulders attitude.Funded by the Scientific Research Project of Sichuan Provincial Department of Land and Resources,the purpose of this paper is to develop a set of boulders attitude detection systems for flume-debris flow experiments by referring to the AHRS design.Firstly,this paper investigates the main methods of research on the law of boulders movement and the performance indicators of AHRS products at home and abroad.Based on the megalithic kinematics theory,this paper will lays the foundation for the follow-up attitude algorithm by the study of the boulder attitude description,the comparative posture update method and the data fusion algorithm.In addition,according to the requirements of the detection of the boulder attitude,the design indicators and overall design of the boulder attitude detection system are proposed.Secondly,this paper carries out the components selection and designs a gesture board with multi-redundancy,wireless transceiver and local storage functions based on low-cost MEMS attitude sensors.At the same time,the measurement accuracy of the sensor is improved by establishing a MEMS attitude sensor error model.Thirdly,the FreeRTOS operation system is transplanted based on ARM micro controller.On the basis of this,the paper develops the programs of chip driver,sensor data synchronization acquisition,sensor redundant fault detection and isolation,attitude calculation algorithm,wireless communication and Micro SD card storage.In addition,this paper also developed the upper computer software with the functions of real-time visualization of the megalithic model,posture sensor fault reporting,and attitude data display.Finally,this paper improves the measurement precision of the sensor by calibration of the attitude sensor calibration.Through the three-axis rotary table test,the static accuracy of the boulder attitude detection system meets the requirements of the indicators with roll angle,pitch angle error less than 0.2°,and heading angle less than 0.5°.And through the flight comparison test to observe the attitude following system of the boulders attitude detection system,in which the dynamic accuracy reaches the pitch angle,the roll angle error is less than 2.5°.In the flume experiment,by comparing the attitude data obtained from the boulder attitude detection system and the multiple positions of the camera video,it is shown that the designed attitude detection system can more accurately reflect the true attitude change process in the boulder migration.At the end of this article,it summarizes the research work done and puts forward the next direction of improvement.