Prototype design and validation of a dual-mode amphibious robot with composite track-propeller propulsion

Abstract

To combine seabed-contact locomotion and basic submerged maneuvering within a compact amphibious platform, this paper proposes a dual-mode amphibious robot with a composite track-propeller propulsion structure. The track drive wheel and an embedded propeller are coaxially integrated within the same composite drive unit, allowing the robot to operate in tracked and submerged propulsion modes. Computational fluid dynamics and underwater pull-force experiments were conducted to evaluate the hydrodynamic performance of the proposed structure. The results show that hub embedding increases the static thrust by 16.5%–23.8% over the tested rotational-speed range of 200–600 rpm. A representative velocity-field comparison further indicates that the surrounding track-wheel hub partially constrains and guides the local flow, producing a duct-like flow-guiding effect that is qualitatively consistent with the measured thrust increase. A prototype robot was subsequently fabricated and evaluated through coastal cross-medium locomotion, seabed-contact tracked locomotion, drive-unit reorientation, and basic vertical-motion experiments. During the coastal experiment, the robot traveled approximately 27.6 m in 42 s, corresponding to a mean ground speed of approximately 0.65 m/s, and its horizontal trajectory was recorded using onboard GPS. The composite drive units rotated through 90° at a commanded average angular velocity of 45°/s, corresponding to a nominal reorientation time of 2.0 s. Video-estimated depth data from a representative pool test also demonstrated ascending, a near-surface dwell period, and descending motions. These results provide prototype-level validation of the proposed integrated propulsion configuration for dual-mode amphibious locomotion.