Self-sensing is important for any soft robot whose shape is easily influenced by its surroundings. Surface- and volume-integrated shape sensing will inform SCRAM robots of their own shape in real-time as they interact with the environment. In SCRAMs, self-sensing also validates whether the SCRAM surface actuators achieved the desired joint configuration.

We use textile-based methods to install sensors and actuators on SCRAM surfaces. Soft, stretchable optical fiber sensors are compatible with these fabrication methods. Because our fibers are sensitive to stretching, bending, and pinching, we have recently investigated methods to decouple these mechanical signals by measuring signal amplitude, pulse time-of-flight, and the amplitude of light coupled in from neighboring fibers. We are also developing materials to control optical transmission between neighboring fibers as a function of pressure. Such materials might detect regions with high surface strain or give SCRAM end-effectors a sense of touch.

Locomotion modelling for SCRAM robots is an exciting field. This illustration shows an example elliptical gait for a symmetric SCRAM swimming robot superimposed on the connection field in part a, a scaled-up illustration of the vertical body displacement of the swimmer at different points along the gait in part b, and the same gait superimposed on the height function in part c. This geometric interpretation relating joint motion to physical movement will be important for path planning and control of SCRAM robots, where SCRAM joints will restrict allowable joint trajectories.

Thin-walled cylindrical tubes can be pinched to create compliant, virtual joints in any radial direction, and then recover their original shape and stiffness once released. Through careful design and material selection, this can result in large changes in stiffness between the original shape, the intended degree of freedom, and orthogonal axes; resulting flexures can then used as passive, compliant rotational joints. Since the manufacturing of these tubes it is compatible with 3D printing processes, its shape can be easily adjusted and reprinted as more is learned about its performance.Thin-walled cylindrical tubes can be pinched to create compliant, virtual joints in any radial direction, and then recover their original shape and stiffness once released. Through careful design and material selection, this can result in large changes in stiffness between the original shape, the intended degree of freedom, and orthogonal axes; resulting flexures can then used as passive, compliant rotational joints. Since the manufacturing of these tubes it is compatible with 3D printing processes, its shape can be easily adjusted and reprinted as more is learned about its performance.

Thin-walled cylindrical tubes can be pinched to create compliant, virtual joints in any radial direction, and then recover their original shape and stiffness once released. Through careful design and material selection, this can result in large changes in stiffness between the original shape, the intended degree of freedom, and orthogonal axes; resulting flexures can then used as passive, compliant rotational joints. Since the manufacturing of these tubes it is compatible with 3D printing processes, its shape can be easily adjusted and reprinted as more is learned about its performance.