The prompt and robust detection of tactile information is a relevant and challenging problem, and a considerable research effort is, thus, being put into innovative transduction methods for tactile sensors. In this article, we investigate the possibility of using event-based cameras to sense contact forces applied to objects by a robot end effector. The proposed optical tactile sensor incorporates a soft hemispherical pad made of silicone rubber with imprinted markers and a pulsewidth modulation light source that emits optical pulses, allowing robust detection of the markers to track deformations of the pad. To test the effectiveness of our sensor, experiments were carried out attaching it to a teleoperated robot arm to finely control it when out of the user's field of view, as accurately as if the user could see it. In the experiments, an augmented reality display and a haptic device were used to convey the force detected by the event-based tactile sensor back to the human operator. The experiments included a practical application of a soft tissue puncturing tool, and psychophysical test results from ten participants were recorded, to validate efficacy and usability of the system.

We report findings from initial exploration into using electrotactile stimulation, on the surgeon's tongue, as a potential lower-latency and less mechanically-complex way to provide force-feedback to the operator of robot-assisted surgery. We conducted a pilot feasibility study wherein participants attempted to teleoperate a robot to grasp and lift chicken eggs without breaking or dropping them. The force measured by the robot's gripper was displayed differently based on the experimental condition: visually only, or visually with electrotactile tongue stimulation. Participants were more successful lifting eggs with tongue stimulation. Data from this preliminary study, along with insights from informal interviews, suggest that tongue stimulation has potential to enhance the efficacy and safety of robot-assisted surgery.

The tongue is a remarkable human organ with a high concentration of taste receptors and an exceptional ability to sense touch. This work uses electro-tactile stimulation to explore the intricate interplay between tactile perception and taste rendering on the tongue. To facilitate this exploration, we utilized a flexible, high-resolution electro-tactile prototyping platform that can be administered in the mouth. We have created a design tool that abstracts users from the low-level stimulation parameters, enabling them to focus on higher-level design objectives. Through this platform, we present the results of three studies. Our first study evaluates the design tool’s qualitative and formative aspects. In contrast, the second study measures the qualitative attributes of the sensations produced by our device, including tactile sensations and taste. In the third study, we demonstrate the ability of our device to sense touch input through the tongue when placed on the hard palate region in the mouth. Finally, we present a range of application demonstrators that span diverse domains, including accessibility, medical surgeries, and extended reality. These demonstrators showcase the versatility and potential of our platform, highlighting its ability to enable researchers and practitioners to explore new ways of leveraging the tongue’s unique capabilities. Overall, this work presents new opportunities to deploy tongue interfaces and has broad implications for designing interfaces that incorporate the tongue as a sensory organ.

Traditionally vibrotactile feedback delivered by haptic interfaces is used to provide additional support for visual interaction via prehensile object manipulation using fingers. Nevertheless, haptic stimuli can be also applied for non-prehensile interaction that involves movements of the elbow joint. In this paper, we have designed a table-top haptic device that provides vibrotactile stimulation to the user’s fingertips. This stimulation creates a kinesthetic illusion of the user’s forearm pivot movement with respect to the elbow joint. The vibrotactile stimulation is amplified by the pseudo-haptic effect delivered through a head-mounted display (HMD). The efficacy of the approach was validated in experiments with human subjects. The results show that the combination of pseudo-haptic and haptic illusion effects can be used to render various soft and rigid virtual objects.