Multi-Loop rover: A kind of modular rolling robot constructed by multi-loop linkages

This paper proposes a new kind of modular rolling robot called multi-loop rover (MLR), which is essentially a multi-loop linkage that is able to roll and switch its rolling directions. For ease of rolling, the MLR retains a multi-loop topological structure composed of a number of strut and node modules. First, the modular design and assembling method are introduced to construct an MLR. Then, the mobility is analyzed based on screw theory, and a brief formula is presented to calculate the degree-of-freedoms of the robot. The results show that all node modules only have translational motions, which can significantly reduce the complexity of kinematics. The forward and inverse kinematics are conducted to show the deformation properties. Based on the kinematic rolling principle, the morphing strategies for rolling and turning functions are developed. Finally, a physical prototype is manufactured and a serial of experiments are carried out to verify the proposed method.