Integrated wheel-foot-arm design of a mobile platform with linkage mechanisms

Inspired by lizards, a novel mobile platform with revolving linkage legs is proposed. The platform consists of four six-bar bipedal modules and it is designed for heavy transportation on unstructured terrain. The platform possesses smooth wheeled locomotion and obstacle adaptive legged locomotion to enhance maneuverability. The kinematics of the six-bar bipedal modules is analyzed using the vector loop method, subsequently ascertaining the drive scheme. The foot trajectory compensation curve is generated using the fixed axis rotation contour algorithm, which effectively reduces the centroid fluctuation and enabling seamless switching between wheels and legs. When encountering obstacles, the revolving linkage legs act as climbing arms, facilitating seamless integration of wheel, foot and arm. A physical prototype is developed to test the platform on three typical terrains: flat terrain, slope and vertical obstacle. The experimental results demonstrated the feasibility of the platform structure. The platform can climb obstacles higher than its own height without adding extra actuation.