In order to enhance the passability and motion flexibility of a mobile robot operating on unstructured terrain, a centipede style multi-drive module articulated mobile robot has been developed. This robot combines passive deformation wheels with flexible articulation devices, enabling it to passively adapt to complex and variable obstacle terrains. Additionally, the passive deformation wheels have been optimized. Based on the study of the passive deformation mechanism of the wheels, a mechanical model of the robot's obstacle-crossing capability has been established, and the robot's passability across different terrains has been analyzed. Experimental results under various terrains demonstrate that the robot features a rational structural design, excellent obstacle-crossing performance, and high motion flexibility, allowing it to passively adapt to complex and variable obstacle terrains.