Design, Analysis, and Flexibility Evaluation of a Double‐Mode Underactuated Coupled‐Drive Omnidirectional Mobile Robot

ABSTRACT Current omnidirectional mobile robots often utilize Mecanum wheels, omnidirectional wheels, or steering wheels, but these technologies present certain operational limitations. This paper investigates a double‐mode underactuated coupled‐drive omnidirectional mobile robot to improve adaptability and flexibility across various terrains. By designing a double‐crank linkage and cross‐slider mechanism, the robot achieves omnidirectional translation and in‐place rotation modes without using the steering wheel. In the translation mode, the four wheels act as an integrated system, always remaining parallel; in the rotation mode, each wheel can independently rotate around its respective yaw axis, enabling the robot to rotate. This structure significantly reduces the turning radius of the robot. By utilizing the cross slider in conjunction with limit blocks, the relative positions of the double connecting rods are constrained, ensuring the robot maintains a constant posture during omnidirectional movement and resolving the uncertainty and dead‐center position issues in the double‐crank connecting rod motion process. The omnidirectional mobile robot studied in this paper has applied for a patent. To validate the feasibility of the robot's motion modes, structural analysis, dynamic analysis, and kinematic analysis were conducted, and the stability and flexibility of the robot were verified through physical experiments.