Towards Automated Welding in Big Shipbuilding Assisted by Programed Robotic Arm Using a Measuring Arm
This paper presents an automated robotic welding system adapted for shipbuilding in large shipyards. This solution has been devised in the shipyard of Navantia located in the south of Spain, in the context of ROBOT FASE II R&D project. It also presents the human teams that have developed this welding system. The article explains the 3 parts that make up the welding system. The location of the robotic welding arm of the Fanuc brand is detailed in the first part. In addition, the gantry and spatial coordinate axes are described and indicated where the robotic arm is housed. The second part contains the system capture of the coordinates in the space for the reading of the singular points to be soldered. These points are measured by a portable measuring arm. The last part is composed of the system of communication between the different parts throughout the computer. The computer is responsible for synchronizing the measuring arm and the robotic welding arm by translating the points to be soldered.
Rail Running Mobile Welding Robot ‘RRX3’ for Double Hull Ship Structure
Abstract ‘Seoul National University’ and ‘Daewoo Shipbuilding & Marine Engineering’ in Korea jointly developed a mobile welding robot, the ‘Rail Runner’ (RRX), which is able to freely move in both transverse and longitudinal directions, and perform welding tasks in double hull structures. Recently, RRX2, (the second version of RRX), was presented at ‘Robotics and Applications 2007'. In this paper, the design, manufacturing, and application of RRX3, the third version of RRX, is described. The moving mechanism of RRX, which is able to move freely in a double hull structure, has two functions. 1) To move in a longitudinal direction by driving wheels using longi. faces as ‘rails', and 2) To move in a transverse direction by sliding along supporting longi. faces using extension arms. The body of the RRX3 is composed of a 12-axis, 6-axis mobile platform that supports the RRX moving mechanism and a 6-axis welding robot to do the welding job. The main point in designing RRX3 is to make it capable of passing through a 600mm×800mm sized access hole, the entrance into an enclosed double hull structure. The full size of the manufactured RRX3 is 1825mm×495mm×569mm, and thus the RRX3 is able to pass through an access hole. The weight is 250kg with a 6-axis mobile platform, 6-axis welding robot, and mounted controller.
An anionic shell shields a cationic core allowing for uptake and release of polyelectrolytes within core-shell responsive microgels.
To realize carriers for drug delivery, cationic containers are required for anionic guests. Nevertheless, the toxicity of cationic carriers limits their practical use. In this study, we investigate a model system of polyampholyte N-isopropylacrylamide (NIPAM)-based microgels with a cationic core and an anionic shell to study whether the presence of a negative shell allows the cationic core to be shielded while still enabling the uptake and release of the anionic guest polyelectrolytes. These microgels are loaded with polystyrene sulfonate of different molecular weights to investigate the influence of their chain length on the uptake and release process. By means of small-angle neutron scattering, we evaluate the spatial distribution of polystyrene sulfonate within the microgels. The guest molecules are located in different parts of the core-shell microgels depending on their size. By combining these scattering results with UV-vis spectroscopy, electrophoretic mobility and potentiometric titrations we gain complementary results to investigate the uptake and release process of polyelectrolytes in polyampholyte core-shell microgels. Moreover, Brownian molecular dynamic simulations are performed to compare the experimental and theoretical results of this model. Our findings demonstrate that the presence of a shell still enables efficient uptake of guest molecules into the cationic core. These anionic guest molecules can be released through an anionic shell. Furthermore, the presence of a shell enhances the stability of the microgel-polyelectrolyte complexes with respect to the cationic precursor microgel alone.