Showing papers by "Ali Israr published in 2020"

A Wearable Soft Haptic Communicator Based on Dielectric Elastomer Actuators.

Abstract: Dielectric elastomer actuators exhibit an unusual combination of large displacements, moderate bandwidth, low power consumption, and mechanical impedance comparable with human skin, making them attractive for haptic devices. In this article, we propose a wearable haptic communication device based on a two-by-two array of dielectric elastomer linear actuators. We briefly describe the architecture of the actuators and their mechanical and electrical integration into a wearable armband. We then characterize the actuators' force, displacement, and thermal properties in a bench-top configuration. We also report on the power and drive circuit design. Finally, we perform a set of preliminary perception evaluations on participants using our haptic device, including detection threshold tests and identification tests for locations and directions on the forearm. Human testing with individual actuators demonstrates that the broadband actuation can be easily perceived on the forearm, providing the basis for both the development of a wearable actuator array and its use in more extensive perception evaluation as described herein.

Multi-Sensory Stimuli Improve Distinguishability of Cutaneous Haptic Cues

Abstract: Wearable haptic systems offer portable, private tactile communication to a human user. To date, advances in wearable haptic devices have typically focused on the optimization of haptic cue transmission using a single modality, or have combined two types of cutaneous feedbacks, each mapped to a particular parameter of the task. Alternatively, researchers have employed arrays of haptic tactile actuators to maximize information throughput to a user. However, when large cue sets are to be transmitted, such as those required to communicate language, perceptual interference between transmitted cues can decrease the efficacy of single-sensory systems, or require large footprints to ensure salient spatiotemporal cues are rendered to the user. In this paper, we present a wearable, multi-sensory haptic feedback system, MISSIVE (Multi-sensory Interface of Stretch, Squeeze, and Integrated Vibration Elements), that conveys multi-sensory haptic cues to the user's upper arm. We present experimental results that demonstrate that rendering haptic cues with multi-sensory components—specifically, lateral skin stretch, radial squeeze, and vibrotactile stimuli—improved perceptual distinguishability in comparison to similar cues with all-vibrotactile components. These results support the incorporation of diverse stimuli, both vibrotactile and nonvibrotactile, for applications requiring large haptic cue sets.

Explorations of Wrist Haptic Feedback for AR/VR Interactions with Tasbi

Abstract: Most widespread haptic feedback devices for augmented and virtual reality (AR/VR) fall into one of two categories: simple hand-held controllers with a single vibration actuator, or complex glove systems with several embedded actuators. In this work, we explore haptic feedback on the wrist for interacting with virtual objects. We use Tasbi, a compact bracelet device capable of rendering complex multisensory squeeze and vibrotactile feedback. Leveraging Tasbi's haptic rendering, and using standard visual and audio rendering of a head mounted display, we present several interactions that tightly integrate sensory substitutive haptics with visual and audio cues. Interactions include push/pull buttons, rotary knobs, textures, rigid body weight and inertia, and several custom bimanual manipulations such as shooting an arrow from a bow. These demonstrations suggest that wrist-based haptic feedback substantially improves virtual hand-based interactions in AR/VR compared to no haptic feedback.

A flexible spiraling-metasurface as a versatile haptic interface

Abstract: Haptic feedback is the most significant sensory interface following visual cues. Developing thin, flexible surfaces that function as haptic interfaces is important for augmenting virtual reality, wearable devices, robotics and prostheses. For example, adding a haptic feedback interface to prosthesis could improve their acceptance among amputees. State of the art programmable interfaces targeting the skin feel-of-touch through mechano-receptors are limited by inadequate sensory feedback, cumbersome mechanisms or narrow frequency of operation. Here, we present a flexible metasurface as a generic haptic interface capable of producing complex tactile patterns on the human skin at wide range of frequencies. The metasurface is composed of multiple "pixels" that can locally amplify both input displacements and forces. Each of these pixels encodes various deformation patterns capable of producing different sensations on contact. The metasurface can transform a harmonic signal containing multiple frequencies into a complex preprogrammed tactile pattern. Our findings, corroborated by user studies conducted on human candidates, can open new avenues for wearable and robotic interfaces.

Chasm: A Screw Based Expressive Compact Haptic Actuator

Abstract: We present a compact broadband linear actuator, Chasm, that renders expressive haptic feedback on wearable and handheld devices. Unlike typical motor-based haptic devices with integrated gearheads, Chasm utilizes a miniature leadscrew coupled to a motor shaft, thereby directly translating the high-speed rotation of the motor to the linear motion of a nut carriage without an additional transmission. Due to this simplicity, Chasm can render low-frequency skin-stretch and high-frequency vibrations, simultaneously and independently. We present the design of the actuator assembly and validate its electromechanical and perceptual performance. We then explore use cases and show design solutions for embedding Chasm in device prototypes. Finally, we report investigations with Chasm in two VR embodiments, i.e., in a headgear band to induce locomotion cues and in a handheld pointer to enhance dynamic manual interactions. Our explorations show wide use for Chasm in enhancing user interactions and experience in virtual and augmented settings.

A flexible spiraling-metasurface as a versatile haptic interface

Abstract: Haptic feedback is the most significant sensory interface following visual cues. Developing thin, flexible surfaces that function as haptic interfaces is important for augmenting virtual reality, wearable devices, robotics and prostheses. For example, adding a haptic feedback interface to prosthesis could improve their acceptance among amputees. State of the art programmable interfaces targeting the skin feel‐of‐touch through mechano‐receptors are limited by inadequate sensory feedback, cumbersome mechanisms, or narrow frequency of operation. Here, a flexible metasurface is presented as a generic haptic interface capable of producing complex tactile patterns on the human skin at wide range of frequencies. The metasurface is composed of multiple “pixels” that can locally amplify both input displacements and forces. Each of these pixels encodes various deformation patterns capable of producing different sensations on contact. The metasurface can transform a harmonic signal containing multiple frequencies into a complex preprogrammed tactile pattern. The findings, corroborated by user studies conducted on human candidates, can open new avenues for wearable and robotic interfaces.

Crossing the Chasm: Linking with the Virtual World through a Compact Haptic Actuator

Abstract: We present a demonstration of Chasm, a broadband screw-based linear actuator that renders rich and expressive haptic feedback on wearable and handheld devices. Chasm renders low-frequency skin-stretch and high-frequency vibrations, both simultaneously and independently, through a single tactor and thereby augmenting user interactions with multidimensional haptic feedback in a light and compact form factor. We embody Chasm in a marker-shaped prototype and integrate it with a virtual reality headset through a robust software framework for real-time control of haptic features. We develop a set of VR scenarios to demonstrate rich tactile feedback rendered with the handheld marker and augment the user experience with feeling of impacts, textures, object stiffness and weight on the hand.