Research On Pose Detection Method Of Boom-type Roadheader Based On UWB Distance Measurement

In China,coal is the main energy source.But the high incidence and contingency of geological disasters in deep coal seams such as gas explosions,rock collapses and water inrushes,pose a great threat to the safety of miners.This puts forward higher requirements for mining safety and high-efficiency in deep dangerous coal seams.Therefore,the unmanned mining of deep coal seams will be the surest path for the development of coal industry in our country,and it is urgent to independently design and manufacture unmanned mining equipment adapted to deep seam mining.For a Boom-type roadheader in the unmanned mining of deep coal seams,autonomous control is the core of realizing unmanned working surface,and remote pose detection is the basis and key to the guidance and control.For a long time,manual positioning with point laser pointers,which not only has limited accuracy but cannot provide all pose and position parameters required for autonomous control of roadheader,is the main means to complete cantilever tunneling operations.Based on the high-precision time resolution of Ultra Wide-Band(UWB)signal in the local area,we propose an Ultra wide-band Pose Detection System(UPDS)of a Boom-type roadheader and its detection method basing on bidirectional time-of-flight distance measurement of UWB signals.It can realize continuous measurements of position coordinates and posture parameters of the boom-type roadheader within a narrow and long confined space.Moreover,it provides a reliable theoretical foundation for autonomous control of the boom-type roadheader and unmanned mining of working surface for coalmine tunnelling.The specific research work is as follows:(1)The UPDS system structure was constructed,and the UPDS detection method and the self-calibration method were proposed.Based on the working characteristics of the Boom-type roadheader,the positioning principle and pose detection principle of the boom-type roadheader are studied,and primary position and attitude parameters of the roadheader are determined;based on the working conditions of the boom-type roadheader and the propagation characteristics of radio signals in the medium,A variety of UWB positioning models for UPDS are compared.Based on the optimal UWB signal ranging parameter positioning model,the UPDS system structure and the UPDS pose detection method are designed.The remote and non-contact continuous measurement of the pose parameters of the boom-type roadheader can be realized;the UPDS positioning solution and attitude angle solution model are deduced.In order to improve the UPDS effective measure distance and reduce the number of mine workers on the calibration of base stations,a UPDS self-calibration method based on 4 positioning base station robots was proposed to complete the continuous automatic calibration of the UPDS system;The UPDS positioning base station robot structure model and UPDS autonomous calibration strategy were designed.(2)The UPDS positioning algorithm based on UWB distance parameter positioning model was deduced.Based on the characteristics of UPDS system,three positioning models based on UWB distance measurement information are established: TOA(Time of Arrival)positioning model,TDOA(Time Difference of Arrival)positioning model,TSOA(Time Summationof Arrival)positioning model;eight positioning algorithms are derived from the three positioning models of the UPDS:a.)based on TOA positioning model: Caffery positioning algorithm,Taylor series expansion positioning algorithm;b.)based on TDOA positioning model: TDOA indirect method,Taylor-D positioning algorithm,Chan-D positioning algorithm;c.)based on TSOA positioning model: TSOA indirect method,Taylor-S positioning algorithm,Chan-S positioning algorithm;and the factors affecting the three positioning model error are analyzed.(3)Simulating and analyzing positioning accuracy and error distribution of the eight positioning algorithms of UPDS based on the measured data of the UWB ranging experiment.The UWB ranging experiment was performed in a narrow tunnel of 10m-95 m,and the UWB P440 module of the American Time domain company was chosen for it;positioning simulations and analyses of the eight positioning algorithms of UPDS are carried out based on the measured ranging data;positioning node distribution,axis error distribution,and the root mean square error(RMSE)contour distribution within 95 m for 8 positioning algorithms are simulated;the characteristics,accuracy and error variation of each positioning algorithm are compared and based on the results of simulation analysis,four positioning algorithms are optimized: Caffery positioning algorithm,a fusion-positioning algorithm based on a Caffery transform and Taylor series expansion(CT algorithm),TDOA indirect method and TSOA indirect method.In order to explore the changing regularity of positioning accuracy of different algorithms in a narrow closed roadway space,a full-section positioning error field for narrow and long enclosed tunnel space was proposed f,with which the accuracy and error distribution of different algorithms in a narrow and closed tunnel can be intuitively reflected;according to the comparison of the full-section positioning error field for the four preferred positioning algorithms,it embodies that the CT positioning method has high positioning accuracy in the narrow tunnel of 10m-95m;therefore,the CT algorithm is regarded as the core algorithm of the UPDS field experiment.(4)The UPDS pose detection field experiment was conducted to verify the effectiveness of the system.The influence of base station geometric layout on positioning accuracy of the UPDS and the influence of the geometry layout of fuselage positioning nodes on the attitude angles accuracy of the UPDS are explored.Based on preferred base station geometry layout,UPDS field experiments were carried out in simulated tunnels in a autonomous control laboratory of a boom-type roadheader,aiming at verifying the feasibility of the UPDS system and the positioning accuracy and attitude angle accuracy of the UPDS in the tunnel;ten roadheader positions were selected for calibration and measurement within the range of 10m-78 m in the simulated tunnel;by analyzing the measured data of UPDS,the centimeter-level positioning accuracy in the X-axis and Y-axis directions can be obtained and the roll angle of the roadheader can reach the detection accuracy of 5°,meeting the mining requirements of the working surface for coalmine tunnelling and providing a reliable theoretical and practical foundation for the realization of the autonomous control of the boom-type roadheader.