The traditional propeller-based propulsion of underwater robots is inefficient and poorly adapted to practice. By contrast, underwater biomimetic robots show better stability and maneuverability in harsh marine environments. This is particularly true of undulating propulsion biomimetic robots. This paper classifies the existing underwater biomimetic robots and outlines their main contributions to the field. The propulsion mechanisms of underwater biomimetic undulating robots are summarized based on theoretical, numerical and experimental studies. Future perspectives on underwater biomimetic undulating robots are also presented, filling the gaps in the existing literature.

In this article, the systematic design, construction, and testing of a novel tunable isolator based on magnetorheological elastomers in coupling shear–squeeze mixed mode have been studied. The influence of magnetic particle volume fraction on field-induced properties of magnetorheological elastomer isolator is studied, and the performance of vibration mitigation of magnetorheological elastomer isolator is evaluated experimentally. The results show that the frequency-shift property of magnetorheological elastomer isolator is linearly proportional to the magnetic particle volume fraction and applied current, and vibration mitigation capacity of magnetorheological elastomer isolator is remarkably enhanced by increasing the applied current. The design of magnetorheological elastomer isolator in coupling mixed mode may provide a new insight for using magnetorheological elastomers in vibration reduction applications.