A reciprocating vector propulsion underwater vehicle based on a parallel reconfigurable mechanism

Underwater propulsion technology is a critical aspect of underwater equipment. The paradigm of underwater propulsion primarily based on propellers diminishes propulsion efficiency due to the lateral induced flow. Addressing this issue, our work proposes a reciprocating straight propulsion underwater propulsion strategy based on a passive folding mechanism. This propulsion form enhances effective thrust, and improves the motion efficiency of the vehicle via adopting the proposed straight propulsion mechanism which eliminates lateral induced water flow. To achieve vector propulsion ability, a 4-PRU parallel reconfigurable mechanism is added to the straight propulsion mechanism. The propulsion principle, parallel mechanism design, overall structure design of the vehicle, and dynamic analysis are detailed presented. Computational fluid dynamics analysis is used to validate the feasibility of the propulsion principle and the reliability of the dynamic model. Experiments confirm that the motion efficiency of the vehicle under uniform acceleration propulsion mode ranges from 61 % to 69 %, which is higher than traditional propeller propulsion methods. Additionally, the vector-propelled vehicle demonstrates good maneuverability in turning tests in a water pool.