Review of underwater adsorptive-operating robots: Design and application

The maintenance of underwater infrastructures and equipment remains dominated by manual operation, resulting in high costs and safety concerns. Recent advances in adsorptive-operating robots and intelligent controls offer new opportunities for underwater engineering operations. However, the universality and automation of robots are insufficient to support large-scale commercial applications. This review focuses on the fundamental design aspects in terms of adsorption, locomotion, visual observation, control, and autonomy. The approaches employed over the past two decades that enable robots to adsorb stably, locomote smoothly, make clear observations, and operate efficiently are described and compared. Robots with different applications are systematically introduced to illustrate the popular topics and value of research. This review aggregates these studies with the aim of revealing the state-of-the-art in underwater adsorptive-operating robots, and discussing future trends in this field.