Design, perception, planning and control for underwater cleaning robotics: Progress, challenges and trends

Traditional electromechanical cleaning equipment remains overly dependent on human assistance when performing cleaning tasks in unstructured marine environments. With the rapid development of robotic technologies, underwater cleaning robots (UCRs) have emerged as a promising alternative, significantly improving the efficiency of underwater cleaning operations. Existing reviews on underwater cleaning robots predominantly focus on either a single cleaning environment or a specific cleaning technology. In contrast, this review is structured around the sequential workflow of UCRs, providing a comprehensive survey of the state-of-the-art research from the past decade across various underwater environments. Specifically, the review analyzes key technological aspects across this workflow, spanning from the recognition of contaminants and debris, through path planning and motion control, to the final execution of cleaning operations. The close interconnections among these components ensure effective and continuous underwater cleaning performance. While this broad scope necessarily involves a trade-off in technical depth for any single subsystem, it enables the identification of overarching research gaps. Consequently, driven by the increasingly intelligent trends exhibited by the continuous development of the underwater robotics industry, this review proposes future research directions focusing on multi-modal data fusion, lightweight design, efficient propulsion-cleaning integration, and the adoption of digital twin and embodied intelligence frameworks. These efforts are expected to not only advance the technological maturity of UCRs, but also contribute to long-term goals in marine environmental protection.