UTC-RS: An Underwater Tracked Cleaning Robot System for Hydraulic Structures

During the inspection and maintenance of the underwater part of hydraulic structures, it is often necessary to clean the surface of a certain area for subsequent operations. At present, there are still few robots capable of underwater fine cleaning. Therefore, this letter introduces the design of a novel tracked robot system that can be used for underwater fine surface cleaning operations. The robot uses a crawling track chassis and is equipped with a self-designed high-precision operating robotic arm, force-controlled grippers, and underwater brushing tools. Considering the complexity of the underwater environment, an underwater force-position hybrid control algorithm suitable for the robot is proposed, taking into account the water flow resistance. Its effectiveness has been verified in the experimental pool and the proposed robot system has been applied in the actual engineering site. The robot achieves a brushing efficiency of approximately 72 m$^{2}$ per hour, with a force control accuracy of $\pm$ 0.5 N, and the cleaning effect shows a significant improvement when compared to the condition before cleaning.