Design of a Variable Wheel-propeller Integrated Mechanism for Amphibious Robots

In order to address the high complexity and low efficiency of amphibious propulsion systems, this paper proposes a novel variable wheel-propeller integrated mechanism for amphibious robots. By adjusting the blade pitch angle, it enables multiple motion modes, including rapid and stable movement on flat ground, obstacle crossing, and omnidirectional movement on water surface. This study establishes a kinematic model for the propeller blades and conducts multi-objective optimization of the structural parameters by considering both the land obstacle-crossing performance and underwater propulsion performance. Based on the optimized structural parameters, a virtual simulation prototype is constructed. Simulation results indicate that when water surface movement, with a driving torque of 3N.m, robot achieves a maximum linear velocity of 1.25m/s and a maximum angular self-rotation velocity of 3.5rad/s. Moreover, varying the blade pitch angle can alter the thrust direction, enabling omnidirectional mobility on water surface. During land movement, with a rotation speed of 60rpm, the highest obstacle-crossing height is 184mm. This wheel-propeller integrated mechanism exhibits robust comprehensive motion performance and environmental adaptability, with convenient motion modes switching.