A TMP ORIGAMI-SHELL REINFORCED BISTABLE SOFT ROBOT

Soft robots have exhibited promising application potential in complex unstructured environments such as exploration and search and rescue. However, challenges such as slow movement speed and vulnerable soft structures still need to be tackled. To this end, this paper proposes a Tachi-Miura polyhedron (TMP) origami-shell reinforced bistable soft robot to address the abovementioned challenges. The bistable system consists of soft bodies spine, tension spring, and TMP origami shell, driven by air pressure to break through the two energy potential barriers of the bistable system, to switch between bistable states and to drive the soft robot to fast movement by rapidly storing and releasing energy. TMP origami can be regarded as a protective shell for soft robots to prevent hard and sharp media from piercing the soft body; in addition, its strain energy during movement contributes significantly to the bistable energy potential wells of soft robots. The constitutive model parameters of silicone rubber, constructed soft body, are identified by combining the material tensile experiments and the fitting of the constitutive model parameters in commercial software. The quantitative relationship between the soft body and the driving air pressure is explored, and a soft robot kinematic model based on the segmented constant curvature method is presented. A series of experimental tests were carried out, finding that the proposed soft robot could still move normally when passing through the extreme environments simulated by the pushpins. It can reach an average speed of 1.81 BL/s on flat ground, with its mass-motion velocity relationship graph located in the intersection region of the soft and rigid robots. Thus, the proposed TMP origami-shell reinforced bistable soft robot can be classified as a rigid-soft coupled robot. In addition, the proposed soft-bodied robot’s ability to move rapidly in complex unstructured environments on stone roads, muddy ground, gutter ways, grassland, and pools has been confirmed.