Design And Analysis On Hydraulic System Of The Telescopic Horizontal Well Traction Robot With Large Traction

With the rapid development of robot technology,in-pipe robot has made great progress.The horizontal traction robots belong to the in-pipe robot,which are widely applied in the field of petroleum development.Due to the complexity of the horizontal well and the increase of the well length,large traction hydraulic drive traction robot is more and more important.However,current traction robots have the following deficiencies: the lack of traction,low adaptability,the weakness of reliability and low operation efficiency,which seriously restrict traction robots scope and the development.In view of the existing problems of traction robot,this paper put forward a large traction hydraulic drive horizontal traction robot based on the flexible supporting structure,including design and analysis of highly efficient and stable walking mechanism and the support structure,design and analysis of large traction power hydraulic drive system and the design of efficient hydraulic power unit.In this paper,the main content and innovations are as follows:(1)To achieve stable walking and strong traction,the hydraulic drive traction robot based on a flexible support structurewas proposed.Based on Axiomatic Design theory,needs analysis,concept design and the coupling analysis are made for the electro hydraulic driven traction robot(EHDTRobot)and purely hydraulic drive traction robot(PHDTRobot),which realized the independent control for the robot speed and traction.The intermittent propulsion principle and the continuous propulsion principle were put forward,and the advantages of the continuous propulsion movement were obtained.Finally,the electro hydraulic robot and purely hydraulic robot system were designed.(2)The mechanical characteristics of the traction robot were analyzed.Traction robot flexible supporting structure characteristics are analyzed to get the relational expression between the static friction force and support force,which shows that the flexible structure can improve the static friction force and the robot ability to the well.Based on the gravity and the closed friction traction robot,the robot traction forces are analyzed.From two aspects of tilted parts and circular arc,the cable resistances in the pipe were analyzed,and the torque characteristics of robot was analyzed(3)Large traction EHDTRobot system is designed and researched.Based on the principle of electro hydraulic robot,system process and the implementation scheme were designed.According to the electric hydraulic system requirements,the system pressure,flow and hydraulic components were determined.Mathematical modeling of the control valve and telescopic cylinder for robot system was established,and the system output characteristic was obtained.Simulation analysis was made on the working process,including motion principle and the walking velocity and the output of traction,which showed the output characteristics and advantages of continuous driving.(4)Large traction PHDTRobot system was designed and researched.Based on the principle of purelly hydraulic robot,system process and the implementation scheme were designed.According to the purelly hydraulic system requirements,the system pressure,flow and hydraulic components were determined.The output characteristic of the core component is researched based on the analysis of drive system mathematical modeling.Based on the simulation analysis,the continuous movement principle,the large output traction and the fast moving speed were validated for the PHDTRobot.(5)The efficient power unit based on two stage pressure source system was proposed.Based on the logging traction robot movement principle and load characteristics,the two-stage pressure source power unit and its working procedure were researched.According to robot energy flow process,the energy loss models of hydraulic system and core elements were established,which showed the effective drive mechanism in two-stage pressure source power unit.The motion of telescopic hydraulic cylinder was simulated to test the feasibility and energy saving effect of the two-stage pressure source power unit.(6)Two types of hydraulic drive traction robot prototypes are developed and the experiments were studied.Electro hydraulic drive traction robot experimental prototype system was developed,electric hydraulic drive system performance test platform and THE valve control output expansion system test platform were established,which was used to test the system operation and the output characteristic.Purelly hydraulic drive traction robot prototype was developed,and its drive principle testing platform was set up.By conducting relevant experimental study,the feasibility of PHDTRobot drive scheme is validated.In this paper,the large traction telescopic hydraulic drive traction robot,including flexible support structure design and mechanics analysis,continuous thrust system design and analysis,and high efficiency design of hydraulic power unit,not only provides a theoretical guidance for the horizontal wells traction robot design,but also promotes the practical process of the large traction hydraulic drive robot.