Design and Performance Analysis of a Bionic Squid Underwater Thruster

Compared with the propulsion mode using the fluctuation or swing of fins, the water-jet propulsion of cephalopods has attracted much attention because of its high swimming speed. This paper introduces a squid-like underwater thruster based on an origami structure, which can realize water-jet propulsion by changing the shape of its origami structure. At the same time, it is combined with a soft vector nozzle driven by negative pressure for underwater steering. In addition, a triboelectric sensor (TES) is embedded in the origami structure to monitor the shape change of the thruster in real time. The kinematics model of the origami structure is established, and the dihedral angle \(\:{\text{B}}_{\text{0}}^{\text{4}}\), which can be used to characterize the unique shape of the thruster, is put forward. The dihedral angle \(\:{\text{B}}_{\text{0}}^{\text{4}}\) is monitored by the TES so that the shape change of the thruster can be feedback in real-time. Prototypes of the thruster and vector nozzle were fabricated, and the maximum error of TES in monitoring the shape of the thruster was less than 4.4%. At the same time, an underwater test platform was built to test the thruster’s propulsion performance and the vector nozzle’s deflection effect.