Wrinkled Soft Sensor With Variable Afferent Morphology: Case of Bending Actuation

The sensor morphology is of great importance, especially for tactile sensors that mainly transduce physical contacts to perceivable signals for further processing by the central system. Sensors with various morphology can result in different signal thus potentially influencing perception. Most previous researches on tactile sensor morphology focused on revealing advance of a particular morphology in a binary manner, by providing sensors with and without that morphology then comparing the performance. Less attention was paid to sensors with changeable morphology. We demonstrate in this letter a wrinkled soft tactile sensor with variable morphology, leading to tunable sensing and perception property. Specifically, the geometrical structure of wrinkles and the overall stiffness of the sensor can be varied by changing the sensor bending state. This morphing behavior was modeled analytically, and verified by both Finite Element Analysis and real experiment. Furthermore, these morphological variations were found to closely affect the performance of sensor in three tasks including force sensing, shape discrimination and texture detection. Interestingly, for each task, there was always an optimal morphological state that maximized the sensor performance, namely force sensitivity and perception accuracy. This sheds light to novel active tactile sensing system design, thus realizing "active" by adapting morphology instead of sensorimotor control algorithm to optimize perception gain.