Surface Shape Changeable Tactile Sensor Using Shape-Memory Polymer

Tactile sensors typically have elastic covers for reducing the impact of objects that make contact with them. However, such covers decrease the spatial resolution of the sensor because of their low-pass spatial filtering characteristics, which vary based on the stiffness of the cover. Therefore, we propose a tactile sensor that uses a shape-memory polymer (SMP) with a stiffness that varies with temperature. SMPs can be deformed above their glass transition temperature (
$T_{\mathrm{g}}$
) upon application of a small load, and they maintain their shape after they have been cooled below
$T_{\mathrm{g}}$
and become rigid. When subsequently heated above
$T_{\mathrm{g}}$
, they return to their initial shape. These characteristics can be exploited to alter the spatial resolution, the rigidity and the shape of the sensor surface by adjusting the temperature of the SMP. In this study, we changed the shape of the sensor surface by utilizing these shape-changing characteristics, and we evaluated the output of a prototype sensor. Utilizing the shape fixity of the SMP, various bumpy surfaces were realized. Through the experiments using the prototype sensor, the sensor was found to be effective at measuring surface profiles.