Development of Embedded Sensor System for 5-DOF Finger-Wearable Tactile Interface

In this study, we develop an embedded sensor system for a previously devised finger-wearable tactile interface, named HaptiCube, that can display five-degrees-of-freedom (5-DOF) tactile feedback. However, owing to the absence of embedded sensors, it could not provide the desired tactile feedback properly. Therefore, a sensor system for the HaptiCube was designed while ensuring that implementing the sensor system does not significantly increase the size and weight of the device. Furthermore, the HaptiCube can simultaneously provide two different tactile feedbacks, i.e., 3-DOF touch/pressure and 2-DOF shear. Hence, the primary consideration factors for developing a sensor system are compact and lightweight characteristics and simultaneous measurement capability of touch/pressure and shear. The developed sensor system consists of two different sensors, i.e., a 3-DOF force/torque sensor and 2-DOF magnetic displacement sensor. In addition, a self-tuning fuzzy proportional-integral-derivative controller was designed for controlling the nonlinearity of shape memory alloy actuators. The improved working performances of the device based on the proposed sensor system and controller were experimentally investigated. In addition, the tests with human subjects were conducted to verify the selective stimulation of 5-DOF tactile feedback and usability of the device in virtual environments.