Study of a miniature underwater robot based on piezoelectric vector jet propulsion

The maneuverability of existing jet-driven underwater robot moving in underwater narrow space is limited by the unidirectional driving force generated by their jet propulsion actuators. In this article, we propose a jet-coupled vector propulsion module (JVPM), which utilizes multi-jet coupling to achieve multi-angle thrust output within a plane. Through numerical simulation, the flow field characteristics and velocity distribution were analyzed, the formation mechanism of multi-direction driving force was described, and the coupling angle was optimized, and the simulation result also showed that under the voltage difference of 50 V_p-p, the coupled jet of the JVPM can deflect by 19.2° in the plane. Subsequently, by conducting particle image velocimetry (PIV) experiment and output performance test experiment, the formation of multi-directional coupled jet was verified, and the signal waveform of the JVPM was optimized. Finally, a 3DOF miniature underwater vector jet-driven robot (UVDR) with dimensions of 90 mm × 82 mm × 73 mm was designed, prototyped, and experimentally evaluated. The experiment results demonstrated that, the UVDR achieved a maximum horizontal linear velocity of 76.4 mm/s (0.93 BL/s), a maximum turning velocity of 0.86 rad/s with a minimum turning radius of 86 mm in the horizontal plane, and a maximum floating velocity of 46.8 mm/s (0.52 BL/s) in the vertical plane, conforming its exceptional maneuverability.