Key Technologies Of Recognition And Disassembly Of The First Wall’s Tiles Based On Vision And Force Feedback

Nuclear fusion energy is the next-generation energy source,which is a research hotspot at present.During the operation of EAST,the first wall need to be remotely maintained during shutdown period.The damaged tiles of the first wall are classified into two types in the dissertation,one of which are fallen tiles and the other of which are damaged tiles but not falling off from the first wall.The identification and positioning of the former tiles and the motion control of the latter tiles’ disassembly process were studied in the dissertation.Visual recognition technology and disassembly technology related to the two main-tenances have developed to some extent.But there are also some difficulties in their application in EAST.In the former’s maintenance,firstly,there are burn and corrosion spots on the surface of the tiles,which makes it more difficult to implement visual recog-nition.Secondly,the forms of the damaged fallen tiles vary,so there is no fixed shape feature for recognition.In the process of disassembling the tiles which damaged but not fallen,the key process is disassembly of the bolts.The bolts of the tiles are mainly hexagon socket,and the head of hexagon socket bolt and its wrench have almost no chamfer.Existing literature rarely involves the hexagonal peg-in-hole assembly with-out chamfer.In the latter’s maintenance,a method based on "breakpoint" image feature was pro-posed.When a fallen tile cover edges of tiles on the lower diverter,some lines of the latter tiles’ edges will be interrupted,and then breakpoints will appear.Therefore,these breakpoints are on the contour of the fallen tile.After breakpoints were found,in the method,two points inside and outside the contour respectively will be found through breakpoints,and transferred to the depth image as the initial point of the watershed al-gorithm,to segment fallen tile’s outline.In order to test the robustness of the method,100 experiments,in which a tile were randomly thrown onto the platform,were made in the dissertation,and in 98 of which,the fallen tile was successfully identified and po-sitioned.And another experiment,in which the illumination intensity is a variable,was also made.In the experiment,it is found that the fallen tile can successfully identified and positioned by the method with the light intensity over 171x,even in the shadow.In the hexagon peg-in-hole task,a method of single side to single side assembly was proposed in the dissertation.In the method,firstly,the approximate position of the hole plane is visually detected to get the peg’s projection line on the hole plane,and then the hexagon peg gets into the hole aslant and moves along all the four sides on the hole plane.And then the peg reaches the state that one side of the hexagon peg fits one side of the hexagon hole according to the feedback of the force sensor.Next,it rotates around the direction that perpendicular to the peg’s projection line on the hole plane.Finally,it stop when it judges that the peg-in-hole matching state is achieved according to the force sensor feedback.The two methods proposed in the dissertation solved some key problems in the recognition and disassembly of the first wall’s tiles.It has contributed to the develop-ment of remote handling maintenance of fusion device.