| The pipes become an important means of transport in industrial facilities,they are connected and installed by welding,and welds parts are the most vulnerable part.In order to ensure the safety of the pipeline transportation,detection techniques are used to identify weld quality problems as well as grinding the weld.This paper is based on scientific research project "The Application Research of pipeline robot in the pipeline construction "(project number:CNEC-CNI23-KY-2015-03),the project comes from China Nuclear Industry 23 Construction Co.,Ltd.Aiming at handling the inner girth weld of the large-diameter thick-walled pipe with various sizes.This paper designs and studies a pipeline robot system for the ?-ray non-destructive testing and automatic grinding of this weld,and the prototype manufacture and experiment of pipeline robot system are completed.In order to achieve the non-destructive ray inspection and automatic grinding of the circumferential weld in the pipe,the functional carrier structure of the pipeline robot system is designed.The system is divided into four parts with idea of modular design,includes mobile unit,detection unit,grinding unit as well as electronic control unit.Among them,the mobile unit provides the ability to move and position for the entire system,the detection unit makes center or eccentric inspection to the specified weld by use ray sources according to requirements,the grinding unit completes the automatic grinding of the weld,the electric control unit achieve planning and control of the system work and feedback image data as well as display status information of system.Based on the premise of all wheel obstacle,a mathematical model to measure the climbing capability of mobile unit is established.The main factors that determine the eccentric focal distance when detection unit makes eccentric inspection is analyzed,and the calculation method that calculation value of weld defect characteristics by using image information.finally,the mathematical formula of grinding force of grinding unit is deduced.Based on the technical requirements about the movement ability of the pipe robot when it is in the elbow pipe in the later stage,the three-axis differential mechanism can be used in the mobile unit are researched.Through the configuration synthesis of2-DOF 2K-H planetary gear train,various configurations satisfying the differential speed are obtained.The configuration condition of this mechanism having themaximum output torque is revealed after transmission equations of each configuration are analyzed.Then,the power flow of the gear train with maximum output torque is plotted,and the transmission efficiency of the gear train under two working conditions is calculated.Finally,according to the theoretical research,the solid model of the three-axis differential mechanism is established and compared with the existing kind of mechanism.The 3-D solid model of the pipeline robot system is established,and the traction capability and the obstacle surmounting performance of the mobile unit are simulated and analyzed,so that the rationality of the system structure design and the theoretical analysis is verified.On this basis,the prototype of the robot system is Manufactured.Then the experimental research on the crawling ability of the system is carried out,which proves that the pipeline robot system has reliable ability of crawling in the tube,and the basic performance index of the system meets the design requirements. |
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