As an innovative underwater propulsion technology, the rim-driven thruster (RDT) has garnered increasing attention due to its advantages over conventional diesel or gas turbine propulsion systems, including reduced noise, higher efficiency, and a compact structure. However, traditional hull–engine–propeller matching theories are not directly applicable to RDTs because of their unique shaftless and ducted characteristics. Based on conventional hull–engine–propeller matching theory and propeller design methodology, this study proposes a novel hull–engine–propeller matching approach tailored specifically to RDTs. The method enables rapid matching by using open-water characteristics for hull–engine–propeller matching. In the absence of open-water test data for shaftless propellers, key parameters derived from ducted propeller tests are used for matching based on open-water characteristics to design the shaftless propeller. The propeller is then optimized through computational fluid dynamics (CFD) simulations to achieve the required thrust performance, effectively enabling an equivalent replacement. The proposed method provides a practical framework for selecting and designing RDTs, improves overall propulsion efficiency, and offers specific guidelines for determining optimal motor design parameters.

Disk motors characterized by a flat structure and high power density are suitable for use in shaftless rim thrusters. This study proposes a novel stator coreless disk motor with skewed wave winding, which is intended for use in shaftless rim thrusters of small underwater robots. It analyzes the generation mechanism of back electromotive force (EMF) and electromagnetic force for the skewed wave winding and designs three disk motors with different pole numbers (12 poles, 16 poles, and 24 poles) by varying the winding skewed angle. A positive correlation between motor efficiency and the number of poles is demonstrated through a finite element simulation on disk motors with different pole numbers. Finally, a prototype of the 16-pole motor is fabricated and tested to validate the effectiveness of the previous motor design

The electrical load and the magnetic load of the transverse flux permanent magnet linear motor (TFPMLM) are decoupled from each other, which makes it easy to achieve modularization, and it has broad application prospects in the field of low speed and high thrust. Firstly, the topology structure of a cylindrical TFPMLM is proposed, and its working principle is introduced. Secondly, the basic electromagnetic performance of the motor is studied. Thirdly, the influence of the structural parameters on the flux linkage, back-EFM, and cogging force has been analyzed by the 3D finite element method (FEM). Then, the kriging agent model is constructed through the DOE experiment, and a set of size parameters with better performance are found by using a multi-objective genetic algorithm. Finally, the prototype and experimental setup have been developed. The calculated results and the measured results are in good agreement.