Development Of Telescopic Micro In-pipe Robot Based On Controllable Locker Mechanism

On the ground of the program of Telescopic Micro In-pipe Robot Based on Unilateral Locking Mechanism supported by the Hi-Tech Research and Development Program (863) of china, the paper aims at the heat transfer pipelines for nuclear reactor evaporator and technological breakthrough of"micro-miniaturization, large traction, rapid speed and two-way locomotion"for in-pipe robot. By comparison of present in-pipe robots in and out of China and absorbing advantages, a new telescopic micro in-pipe robot based on controllable locking mechanism was presented. Following the flow of design, analysis, optimization and prototype development and test, the research of the new micro in-pipe robot was processed. The main work done in this paper is as follows:1) On the ground of the telescopic micro in-pipe robot's boosting principle, which was based on locking mechanism, several one-way locking mechanism that could be applied to this sort of robots were compared, and their advantages and disadvantages were described. And Considering practical requirements, a new controllable locking mechanism is presented. Then kinetic principles of robot with this mechanism were analyzed.2) For instructing the design and optimization, the pinciple cam's self-locking and the influence of torsional spring to self-locking was analyzed. And, by building the mathematical model of cam's curve face and controllable locking mechanism, the requirements for the curve face's parameters and changing locomotion directions should meet were presented. Then the diameter's scale which the robot could be adaptable to was analyzed.3) The whole structure of this robot was designed in detail, the working principles of controllable locking mechanism and driving mechanism were described, and parameters needed were also calculated in detail. According to characters of locking mechanism, parameters of links and magnitude of commutating forces were calculated comprehensively, enabling the reliability of commutation. To ensure the robot own a large traction and speed, driving lead screw's parameters were selected and strength was checked. Then the transmission efficiency of transmission structure was computed, offering choosing evidence for the driving motors.4) The prototype was successfully developed, and a comprehensive test system was built. Aiming at the feature that locking direction could be controlled, tests were carried out. What's more, tests about velocity and traction were carried out. Finally, robot's adjustment to pipe's diameters and two-way locomotion were also tested. Results demonstrated that this robot's prototype can move steadily in pipe with diameter fromΦ17~20 mm, own a traction value of 12 N at the speed of 10 mm/s, climb slopes with degrees ranging from 0~90o, and carry a two-way movement. These all well meet the design of goals of"micro-miniature, large traction, rapid speed and two-way locomotion"for the in-pipe robot.