Design and analysis of a hexagon rolling mechanism with a center-arranged actuator

Abstract

This paper proposes a novel hexagon rolling mechanism, which is composed of inner multiple crank links and outer six-bar chain, driven by a center-arranged actuator (CAA). The rolling locomotion of the hexagon rolling mechanism with single degree of freedom (DOF) is realized by the coupling motion of inner and outer mechanisms, and the locomotion direction is determined by the full rotational direction of CAA. The coupling motion is realized through the combinations in multiple crank links of inner mechanism and the connections between the outer and inner mechanisms, and the design process is carried out. The trajectories of vertices and center of mass (CM) are analyzed to realize the continuity of the coupling motion. By setting the CM as coordinate origin and the overconstrained sliders as equivalent frame, the coupling motion is matched and parameters of links are preliminary designed without singular positions. Meanwhile, by setting supporting links as equivalent frame alternately, the fluctuation of the CM is improved based on the parameters modification. Finally, the functionality of the rolling mechanism is verified by a manufactured prototype.