Tactile Sensor using Shape-memory Alloy Wires for Human-like Tactile Perception

The recent research has revealed that the deformation caused by applied stress to a shape-memory alloy (SMA) generates a change in the electrical resistance caused by the superelasticity. We have also developed a novel micro-vibration actuator driven by periodic electric pulse current, by employing the shape-memory effect of an SMA wire. The actuators are effectively applied to various types of tactile displays to present different tactile sensations on human skin. By effectively employing the physical property of the superelasticity related with the resistance change, the SMA wire is applied to a micro-force sensor with the high sensitivity, while generating micro-vibration. In this paper, a novel tactile sensing system is proposed by arranging plural SMA-based sensors in an array. For the evaluation of the micro-force sensing ability, experiments are conducted by employing six common objects with different surface texture and stiffness. The result shows the introduced tactile sensor structure has the characteristics to be applicable for human-like tactile perception.