Design of a Self-Reconfigurable Drain Mapping Robot with Level-Shifting Capability

Nature has always been an inspiration for engineers and designers to have technological inventions. The postures, locomotion and gait cycles of animals are usually smooth, dynamically stable, and highly adaptable in an unknown terrain. Based on a giraffe's leg folding pattern, we develop a quadruped hybrid drain mapping robot with modular sub-systems, four bar inversion mechanism based legs and bi-directional rolling wheel, named, Tarantula-II. The platform undergoes self-reconfiguration and achieves variable height and width, which in turn helps in navigation in a drain with multiple level-shifts. This paper describes the key features of giraffe's limb, how the folding pattern of the limbs are implemented in the robot design. In addition, we discuss the detailed mechanical design of platform, the kinematics analysis of each leg, kinematics of the platform with respect to wheels, and structural analysis of the platform under different gait condition. Applying the kinematics formulation and posture correction algorithm, we verify the mobility and level shifting capability of the platform both in lab setting and drain environment.