Development of an Antihydropressure Miniature Underwater Robot With Multilocomotion Mode Using Piezoelectric Pulsed-Jet Actuator

The high-pressure environment of deep-sea challenges the miniaturization of underwater robots due to the assembly of antihydropressure devices for protecting the electromagnetic motor. Here, inspired by the motion principle of jellyfish, a novel piezoelectric pulsed-jet actuator (PJA) was proposed as the power source. Six PJAs were arranged crosswise to form an antihydropressure miniature cross-shaped underwater robot (CSUR) with dimensions of f10.9 x 6.3 cm(3). The numerical simulation method was adopted to analyze the propulsion mechanism, optimize the structure, and find the optimal frequency. A robot prototype was fabricated, and its motion performances were tested. The CSUR achieved floating, sinking, and hovering motions in the vertical direction and linear, rotary, and turning motions in the horizontal direction. The maximum linear velocity reached up to 47.8 mm/s (0.43 BL/s). The robot could move in a high-pressure environment of 10 MPa, and the average velocity deviations under different water pressures were less than 10%. Besides, the CSUR could move along an S-shaped path to navigate around obstacles. The proposed robot performed merits of miniature structure, good adaptability of a high-pressure environment, high agility, and maneuverability. It is potential for the CSUR to be applied in exploring, mapping, and sampling narrow areas of the deep sea.