Robotic System For The Inspection Of Narrow Spaces Between Small Industrial Pipe Bundles

One of the most important peaceful utilization of nuclear energy is to generate electric power. Being vital to nuclear power plants, the steam generators in pressurized water reactor plants are extremely difficult to maintain. The research of robotic system for the inspection of narrow spaces between small industrial pipe bundles was carried out to meet the demands of the automatic inspection of the heat exchange pipes in steam generators. As a portion of a major project supported by Natural Science Foundation of China, this project has done some fundamental research on the key technologies for the robotic inspection of the outer surface of pipe bundle in steam generators, and an experimental in-bundle robotic system has been successfully developed.The research of pipe robots is currently a hot issue of special robotics technologies. Robots outside pipes are more difficult to develop due to the lack of the guidance and support from the inner pipe surface. At present, in China, most of the routine check on heat exchange pipes in steam generators is still being done by manpower. It's very hard to access the gap between any two rows of pipes because of the narrow distance. Therefore, the inspection task of the outer surface of the pipes is really difficult to accomplish.This dissertation introduces firstly the working process of pressurized water reactor plants, the structure, function and in-service inspection of steam generators, and the foreign and domestic state of the art in pipe robots has also been investigated. The basic performance demands on in-bundle robot has been analyzed and a systematic scheme based on specified conditions has been proposed.Because the longest distance of inspection movement in the gaps is much longer than the width of the robot, a flexible module has been developed to push a micro vehicle carrying a micro camera into the gaps and retract it from the gaps. The differential equation of the deflection curve of the flexible steel belt before the landing of the micro vehicle was set up. After proper simplification and linearization, the deflection equation has been obtained. The landing position and the transformation of the pose of the micro vehicle have also been investigated.A novel mechanism, 3-CSR parallel platform robotic mechanism has been proposed. Its model has been set up and arithmetic vector method was used to analyze the position and pose of the mechanism in direct and indirect kinematics. A micro 3-CSR parallel mechanism actuated by bias two way SMA actuators was developed toadjust the pose of the micro camera, thus effectively expanding the inspection scope.A positioning module is used to efficiently locate the in-bundle robot. The module is composed of several basic mechanisms, and it takes advantage of the pipes to perform its function. Total differential method was applied to analyze the error of the positioning module, and the positioning error equation has been concluded, thus providing theoretical basis for the distribution of parts' tolerance.The control system of the in-bundle robot consists of two levels of computers. The first level is a personal computer, which performs the function of monitor and display. Serial Communication is realized via RS-232C bus between the two levels. The second level contains AT89C51 computer and peripheral circuits, including single chip computer unit, communication interface unit, stepping motor driving control unit, DC motor driving control unit, parallel mechanism control unit, opto-coupler driving unit and position signal processing unit. Research on the fuzzy control system of longitudinal mobile platform has also been carried out.The video inspection system of the robot has been developed. A grey evaluation method was put forward to evaluate the qualities of inspected areas by the acquired images, and an example was given to demonstrate the method. This method, combining qualitative evaluation with quantitative evaluation, lays major emphasis on the latter. Based on fundamental information, the method can draw high...