We developed a mobile robot that rolls by the active deformation of the soft outer shell. The robot has a wire drive module and soft outer shell that are joined only by prestressed wires. The soft shell and wire drive help to achieve a tough, low-cost, and lightweight design.
For more detail, see the conference paper:
Yoichi Masuda and Masato Ishikawa, "Development of a Deformation-driven Rolling Robot with a Soft Outer Shell", IEEE International Conference on Advanced Intelligent Mechatronics (AIM2017)