Design of a Novel Quadruped Robot Based on Tensegrity Structures

At present, most of the researches on quadruped robots simplify the spine structure into a rigid body, which limits the flexibility of quadruped robots. As a result, the ability of quadruped robots to cope with different terrains is still much lower than quadrupeds. Tensegrity structure is composed of a set of discontinuous compression elements and a set of continuous tensile elements. As a self-supporting and self-stressing spatial grid structure, tensegrity structures combine the advantages of both rigid structures and soft structures. In this paper, the tensegrity structure is introduced into the structural design of quadruped robots in order to improve their flexibility, adaptability and safety. First of all, a flexible multi-segment spine connected by 3-degrees-of-freedom tensegrity joints is designed. Then, a tensegrity limb that has the potential to realize 3-degrees-of-freedom movement is proposed. On this basis, a novel quadruped robot based on tensegrity structure is obtained by integrating the spine and limbs. Finally, a preliminary prototype of the quadruped robot without actuation is assembled. The feasibility of the proposed concept and structure of the quadruped robot are verified by some simple experiments. It is proved that this prototype has better flexibility and adaptability to complex terrains compared with traditional quadruped robots.