Development of a novel dual-motor driven wheel–foot transformation mechanism for wheel-biped robots

Balancing mobility and adaptability in complex environments remains a major challenge for wheeled and biped robots, highlighting multi-modal actuation as a key research focus. This study proposes, designs, and experimentally validates a dual-motor wheel–foot transformation mechanism for wheel-biped robots, enabling both wheeled and legged locomotion. Guided by a “flip-deploy” design concept, the mechanism integrates a screw-nut drive, linkage system, and sliding block-slot mechanism in a coaxial dual-motor layout, achieving reliable bi-directional switching between wheeled and footed modes. The transmission relationships during the mechanism’s mode-switching process are analyzed, and the linkage lengths are optimized based on static force analysis in the footed mode. No-load, model validation and on-robot experiments demonstrate that the mechanism satisfies the design requirements, enabling stable, rapid, and robust posture transitions while exerting negligible influence on the robot’s overall posture stability. Overall, the proposed design makes it possible for wheel-biped robots to achieve multimodal locomotion and adapt to diverse terrains.