Soft robotics has emerged as a promising approach for robotic operation in confined and unstructured environments, leveraging compliant materials and deformable structures to achieve adaptability beyond that of traditional rigid-body systems. An important subclass of soft robots is multi-stable robots, which possess multiple stable configurations and can maintain a given state without continuous energy input. These characteristics make multi-stable soft robots attractive for applications requiring passive stability, robustness, minimal actuation, and mechanical simplicity. However, the static behavior of elongated multi-stable soft robots interacting with their environment remains an open area of investigation.
This work investigates the static response of an elongated multi-stable soft robot in a planar environment with obstacles. The robot is modeled as a long, segmented, compliant structure in which each stable state of a unit segment (closed, open, or bent) is represented by a distinct set of mechanical stiffness parameters. The study examines how environmental interactions reshape the static equilibrium deformations of such robots. Particular emphasis is placed on the influence of gravity, external loads, and geometric constraints imposed by contact with obstacles on equilibrium shapes and the distribution of internal forces.
