Deformation Sensing in Soft Bio-Surrogate Materials

Deformation sensing in and on soft materials has garnered increased interest with the advancement of emerging technologies such as soft robotics, wearable computing, and biomedical applications. These applications have a need for quantification of stretching-contraction deformations along a single-axis as well as multi-directional deformation quantifications (i.e. bending, pressure, membrane stretch, planar and torsional shear).

These measurement devices must conform to the movements of the device or component under test, which can be complex, involving multiple degrees-of-freedom and dynamic rates, while closely matching the mechanical properties of the system they are embedded in, such as skin, tissue, textiles, and soft actuators. For example, soft actuators are increasingly used in the fields of bio-fidelic robotics and aerospace, however, there is an absence of reliable positional and force feedback, which is necessary to provide a soft touch as well as accurate and controllable behavior. Soft sensors are being implemented to provide this feedback, however, embedding them without hindering the actuator's functionality has been a significant challenge.