A review of the development, research progress and key challenges in underwater bionic soft robotics

Abstract

Conventional rigid underwater robots possess high structural stiffness and exhibit a single mode of locomotion, showing poor adaptability in complex flow fields, narrow spaces and eco-friendly underwater operations. In recent years, underwater bionic soft robots have achieved rapid development boasting a rich variety of bionic prototypes as well as innovative actuation and control strategies. Nevertheless, most existing reviews focus on individual technologies, and few systematically integrate technological evolution, state-of-the-art progress and technical bottlenecks. Adopting a literature review approach, this paper investigates representative domestic and foreign papers and prototypes in the past decade. Through classification, comparison and induction, it sorts out the development history and summarizes mainstream technical systems of bionic structures, flexible actuation and sensing-control systems. The results reveal that this field has experienced three phases: exploration of rigid bionic prototypes, development of fully soft‑bodied robots. However, difficulties in fluid-solid coupling dynamic modeling, limited underwater sensing accuracy, high actuation power consumption and poor adaptability to complex sea conditions remain major obstacles to practical deployment.This paper can provide references for further research tailored to practical nearshore tasks including coral-reef ecological survey, coastal organism-behavior observation, narrow-reef-crevice hazard inspection and man-made underwater-facility patrol of underwater bionic soft robots.