Micro and Nano Engineering (Aug 2022)
A wearable and smart actuator for haptic stimulation
Abstract
Wearable tactile technology in the configuration of actuated thimbles is used to provide the sense of touch in virtual (VR) and augmented reality (AR) and teleoperation contexts. The design of these types of devices includes specific purposes: limiting the overall dimensions of the system to enhance the wearability and increasing the effectiveness and naturalness of the stimulation. This new generation of wearable touch systems can transmit tactile signals more naturally, whilst also being comfortably worn by the user, portable and integrated in daily life. In this direction, we propose a haptic device based on electro-cutaneous feedback to selectively stimulate each mechanoreceptor to discriminate specific tactile sensations. Two important features characterize and make our device innovative: wearability and ease of use. The first feature is enhanced by a flexible holder made of a combination of polydimethylsiloxane (PDMS) and Kapton layers, that allows the device to be wrapped around the fingertip to provide stimulation in the area with higher density of mechanoreceptors and make possible to place the system ground close to the stimulus application point. A more complex stimulation enhances increasingly accurate tactile sensations, so the guidelines of our research were focused on the enrichment of parameters variety that define each stimulation (frequency, waveform, duty cycle, current intensity, anodic/cathodic configuration, and dynamic stimulation) by the development of a functional electronics board (4 h of autonomy per battery discharge cycle). The second feature uses the Bluetooth Low Energy (BLE) protocol to connect the electronic board of the device to a common smartphone, which allows user to manage the stimulation through a specific Android application allowing intelligent and integrated control of the haptic microsystem. Our haptic device is lightweight, does not affect normal hand movement, portable and easy to manage via your smartphone; this makes it available to a large scale of people.
