Abstract:

To enhance the obstacle-crossing and terrain adaptability of mobile rescue robots in complex environments such as unstructured scenerios and mine disaster roadways, a variable-diameter wheel based on the waterbomb-origami principle was designed. Addressing the limitation of exisiting modeling approaches for waterbomb wheel structures, which rely on a single basic unit, a unified modeling theory was proposed that incorporates square, rectangular and parallelogram units as fundamental elements. By establishing multi-coordinate kinematic models for the wheel axle layer, wheel support layer, and wheel connection layer, and systematically deriving the corresponding constraint equations, a unified description and parametric analysis of the folding and deployment process of waterbomb wheels with different unit configurations was achieved. The variation trends and effective ranges of key state variables during folding and deployment were studied in detail, and deploy ability tests were conducted on prototype robot models fabricated via multi-material 3D printing. The results show that the kinematic modeling method is applicable to waterbomb wheel structures composed of different basic unit types. The maximum deployed diameter obtained from testing is 124.35 mm, with a 2.5% deviation from the design value, and the deployment ratio reaches 2.015. During testing, it was observed that the fold and deployment process of the actual structure closely matches the kinematic model, demonstrating the strong applicability and accuracy of the proposed modeling theory.

Key words: waterbomb wheel structure, robot, origami, kinematic modeling, deployment