Design And Analysis Of Large Diameter Changing And Modular Pipeline Robot

In order to solve the problem of difficult manual operation in nuclear pipelines,this paper designs a large diameter-changing modular pipeline operation robot,which solves the problem of climbing large diameter-changing vertical pipelines and diameter-changing T-shaped pipelines through right-angle transition.The range of the adapted pipe diameter is 0.8 times of the minimum pipe diameter,and the minimum turning radius of the adapted bent pipe can reach 1.5D days.Based on the pipeline robot designed in this paper,the theoretical rotation speed to avoid internal friction in the elbow pipe is obtained.The pipeline robot designed in this paper adopts a "modular" design method.The "modular" pointer designs independent modules for specific functions,and each module can be quickly disassembled and installed,thus improving work efficiency and saving a lot of cost.In order to climb the vertical pipe,the pipeline robot needs more traction than its own weight,and designs a combination of wheel and crawler to complete the power system design.According to the possible weld defects and foreign matters in the pipeline,the corresponding operating system is designed.Each module is connected with a quick-change component by using a double cross universal joint,so as to realize quick disassembly and installation among the modules and ensure the passage of the bent pipe;According to the operation conditions inside the pipeline,the operation modes are divided into six types,and the final assembly and performance parameters are arranged.The wedge angle effect,the closing force of the supporting mechanism and the driving force of the steering module are analyzed according to the designed driving mode.The physical model of the large diameter-changing modular pipeline operation robot is established,the traction force and the stress relationship between modules are analyzed,and the causes of deflection inside the pipeline are obtained.According to different pipelines,the friction formula between the pipe wall and the cable is obtained,and the driving distance of the robot inside the pipeline can be judged according to the traction force.The geometric constraint relation of different pipelines to the pipeline robot is analyzed,and the passability of bent pipe and T-shaped pipeline is obtained.The motion characteristics of the pipeline robot in the pipe are analyzed,and the track of the contact point between the wheel of the pipeline robot and the pipe wall in the transition phase and the turning phase is obtained,and the wheel rotation speed without internal friction when the robot turns is obtained.The geometric composition of Tshaped pipeline is discussed,and the motion strategy of pipeline robot through T-shaped pipeline is analyzed.The obstacle-surmounting capability of robots in pipelines is analyzed,and the factors that affect the obstacle-surmounting capability and the methods to improve the obstacle-surmounting capability are obtained.Based on the virtual prototype technology,the traction force of the pipeline robot is simulated and verified,and the relationship between wedge angle pressurization,wheel rotation speed in the elbow and turning radius is verified.The pipeline robot is used to carry out simulation verification through the strategy of right-angle transition T-shaped pipeline,and the correctness is obtained.The variation of the rotating center of the grinding manipulator during operation is simulated,and the friction force of the grinding wheel is simulated and verified.Trajectory simulation is carried out for the suction and scanning manipulator.The simulation has verified the pass-through of the large diameter-changing modular pipeline working robot connected by double cross universal joints in the 250mm elbow pipe.