Study of an Untethered Bioinspired Piezoelectric Father-Son Robot for Deep-Sea Narrow Space

Wireless motion and miniature size are two essential features for deep-sea robots applying in the practical confined area, which are incompatible due to the existence of onboard power supply and anti-pressure devices. Here, inspired by the energy-saving hitchhiking behavior of marine remora, we propose a piezoelectric-jetting father-son robot with size of Φ14 × 13 cm³. The untethered father robot provides power for the adsorbed 5-cm-length son robot, and the micro agile son can detach to freely move in the small space that is inapplicable for father. The structural shapes of lateral jetting unit are optimized by numerical simulation and the corresponding flow field characteristics are elaborated to assist the optimization analysis. Then, the pressure-resilience electronics circuits are designed, and it can normally output high-frequency square wave of 210 V_p-p and excite the father-son robot to implement the wireless 3-DoF motions under 20 MPa environment. Finally, two robots cooperate to detect a cornering channel with width of close to father diameter, and the son recombines the father and together return voyage after the son achieves the multiple high-difficulty movements in such a narrow channel. This work can supply solution of developing the underwater robot in complex deep-sea occasions.