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![Haptic input devices. Controller input devices: a) Gamepad (PlayStation5). Reproduced with permission.[³⁷] Copyright Sony Interactive Entertainment Inc. b) VR controller (Quest 2 Controller). Reproduced with permission.[³⁸] Copyright Oculus. Gesture input devices: c) DataGlove. Reproduced with permission.[⁴⁰] Copyright 1986, ACM. d) Power Glove. Reproduced with permission.[⁴²] Copyright Evan‐Amos. e) Attachable VR tracker (VIVE tracker). Reproduced with permission.[⁴⁵] Copyright HTC Corporation.](profile/Shuo-Li-38/publication/352066240/figure/fig5/AS:11431281173289044@1688822582705/Haptic-input-devices-Controller-input-devices-a-Gamepad-PlayStation5-Reproduced.png)
Haptic input devices. Controller input devices: a) Gamepad (PlayStation5). Reproduced with permission.[³⁷] Copyright Sony Interactive Entertainment Inc. b) VR controller (Quest 2 Controller). Reproduced with permission.[³⁸] Copyright Oculus. Gesture input devices: c) DataGlove. Reproduced with permission.[⁴⁰] Copyright 1986, ACM. d) Power Glove. Reproduced with permission.[⁴²] Copyright Evan‐Amos. e) Attachable VR tracker (VIVE tracker). Reproduced with permission.[⁴⁵] Copyright HTC Corporation.
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Since the modern concepts for virtual and augmented reality are first introduced in the 1960's, the field has strived to develop technologies for immersive user experience in a fully or partially virtual environment. Despite the great progress in visual and auditory technologies, haptics has seen much slower technological advances. The challenge is...
Citations
... [14,18,19,26,27] Dielectric Elastomer Actuators (DEA) have emerged as a promising alternative. [28,29] By using soft polymeric materials, DEA-based haptic devices possess excellent flexibility and portability. However, they require high voltages (up to kilovolts) for actuation and can only achieve limited displacement. ...
... [11] Recent research efforts have been devoted to exploring a 5-DoF actuator using shape memory alloys (SMA). [29] However, the SMA-based actuation mechanism faces challenges in terms of response time and efficiency due to the prolonged heating/cooling time. Moreover, except for DEA-based devices, other haptic interfaces fail to match the stretchability of the skin. ...
The rapid advancements in artificial intelligence, particularly in the domains of robotics, prosthetics, and virtual and augmented reality (VR/AR), have driven an escalating demand for intuitive and effective human–machine interactions. Consequently, haptic devices, being electronic displays for the sense of touch, have drawn increasing attention. More efforts are in demand to develop stretchable and lightweight haptic devices that can trigger multiple mechanical cutaneous receptors using a single device. This work presents a new 3‐modal 5‐DOF stretchable haptic interface that is enabled by electromagnetic actuators and high‐fidelity multi‐layer metal printing. The haptic device renders rich haptic sensations (i.e., normal force, vibration, angular force, skin dragging) in one device, allowing for the comprehensive delivery of tactile information through the excitation of multiple cutaneous receptors. Additionally, haptic devices are designed to be compact, lightweight, and skin‐compatible. The skin‐like softness and stretchability enable intimate skin contact, which is crucial for efficient haptic information delivery. This feature prevents the impediment to natural movements of the skin and ensures the functional integrity of the device during daily deformations of the skin. Finally, three proof‐of‐concept demonstrations illustrate the potential of the reported multimodal haptic devices for advanced haptic interactions across various domains.
... Haptic technology potentially bridges virtual worlds and physical environments to realize the immersive virtual reality (VR) interaction experience, and sensory reconstruction in prosthetics. [1][2][3][4] Wearable electronic devices and materials are at its core. [4] Wearable haptics target to integrate sensing and feedback functionalities into compact devices to create a closed loop of sensing and tactile sensations for the human body. ...
Wearable haptic devices are developed as key components to enhance the highly immersive metaverse experience. However, conventional haptic devices enabling the sensation and interaction with virtual objects are often constrained by their bulky design, tethered operation, and physical interference with the skin, especially when integrated with human hands. In this study, a cross‐interface modification process that achieves the conversion of multilayered silk fibroin films from rigid to soft is reported. This modification is favorable for applications involving large angles and multiple degrees of freedom motions. By applying electrical current through silk‐based electrodes and utilizing a self‐designed circuit, virtual tactile sensations can be generated on the entire palm. The high flexibility, stretchability, tailorable modulus, and water permeability of silk substrates enable the electrotactile devices to maintain their functionalities without impeding fine movements and natural tactile sensations in the hand. This compact electrotactile system serves as a user's new interactive terminal through wireless communications. The intimate contact interfaces reduce the unstable adhesion commonly encountered in electrotactile applications, ensuring consistent sensation during hand motions. These materials design methods and integrated systems represent a significant advancement in fabricating and integrating large‐area soft electronics.
... Silicone elastomer's young's modulus is about 10 5 Pa, matching the human skin (<10 6 Pa) [40]. It is soft and safe for skin and the actuators are non-electric, lowcost, and easy to fabricate [2,26,39,44]. Considering the need for resolving the rigidness and providing natural and skin-like haptic experiences, pneumatic elastomeric actuators have the potential to become the breatHaptics material of choice. ...
... These actuators offer remarkable advantages, including low operating voltages, high deformability, controllable generation force, and lightweight properties, making them ideal for the development of soft electronic devices. [1][2][3] While many high DOI: 10.1002/adfm.202314087 -performance iEAP actuators can achieve substantial bending deformation using functionalized materials rich in ionic liquids, they often overlook the aspect of force generation. ...
This study presents a novel micellar cubic ionic liquid‐crystalline polymer electrolyte, featuring an alignment‐free spherical structure with unimpeded 3D ionic pathways, aimed at enhancing the performance of an ionic electroactive polymer actuator. The development involved creating a mechanically tough and high ion‐conductive cubic polymer film through the self‐assembly of a wedge‐shaped vinyl imidazolium salt and an imidazolium ionic liquid, followed by in situ photopolymerization. The 300 µm‐thick‐trilayer films, consisting of the cubic polymer electrolyte sandwiched between poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS) electrodes, exhibit remarkable capabilities. These include bearing substantial loads of 4 g with a high blocking force under a DC voltage of 2 V, achieving a high bending strain of 0.63% under a low input voltage (±2 V, 0.1 Hz), and boasting a maximum response frequency of 70 Hz. These properties position the material for potential applications in soft robots and tactile sensing devices.
... Static-pressure and vibrotactile feedback are among the haptic feedback mechanisms used in VR/AR applications [6]. The soft thimble actuator, as proposed by Talhan et al. in [7], has demonstrated its capability in augmenting reality. ...
... Recent work on elastomeric actuators has shown potential in addressing these challenges [6]. Dielectric elastomeric actuators [6,[12][13][14][15] and pneumatic actuators [6,7,[16][17][18][19][20] have demonstrated their capacity to offer both static-pressure and vibrotactile feedback at a relatively smaller form factor and weight. ...
... Recent work on elastomeric actuators has shown potential in addressing these challenges [6]. Dielectric elastomeric actuators [6,[12][13][14][15] and pneumatic actuators [6,7,[16][17][18][19][20] have demonstrated their capacity to offer both static-pressure and vibrotactile feedback at a relatively smaller form factor and weight. Despite their compactness, dielectric elastomeric actuators often demand high operating voltages and can require intricate fabrication procedures [12][13][14][15]. ...
In the realm of virtual and augmented reality (VR/AR) and teleoperation applications, haptic feedback plays a role in enhancing task performance. One of the main goals of this study is to simplify haptic device hardware while improving its capacity to provide various stimuli at different intensities. In response to these challenges, this research introduces the Pneumatic Unit Cell (PUC), a soft pneumatically driven device—a hollow silicone cylinder with the ability to provide both static-pressure and vibrotactile feedback. Furthermore, the Pneumatic Unit Cell’s design simplicity has the potential for scalability, modularity, and the flexibility to mount the device on any part of the human body. The focus of the current paper is to study PUCs as actuators and lay the foundation for future perceptual studies. The characterization studies encompass the fabrication and verification of the fabrication accuracy through dimensional measurements, characterizing PUCs under static-pressure conditions (measuring the free deflection and blocking force) and frequency conditions (measuring the free deflection). In the static-pressure conditions, we applied pressures ranging from 0 to 40 kPa to measure the free deflection and from 0 to 30 kPa to measure the blocking force. In the frequency conditions, we applied pressures of 10, 20, and 30 kPa with inflation/deflation rates varying between 0.5 Hz and 100 Hz. The measurements of free deflection under static-pressure conditions revealed that 0.9 mm and 1.2 mm PUCs exhibit a linear increase in free deflection with an increase in inflation pressure. The results of free-deflection measurements under the frequency conditions indicate a direct relationship between the free-deflection magnitude and applied pressure. The results also demonstrate an inverse relationship to the frequency of inflation/deflation. The characterization results demonstrate a broad range of free deflection observed under both static-pressure and frequency conditions, encouraging the potential application of Pneumatic Unit Cell actuators as haptic devices.
... The state of theoretical studies of MAEs is discussed at length in [7,11,23,24]. The interest surrounding MAEs is driven by their potential applications in civil engineering as vibration dampers, remotely controlled switches, and noise control systems [25][26][27][28][29][30][31], in soft robotics as actuators [13,14,[32][33][34], in entertainment as parts of haptic feedback devices [15,[35][36][37], in biomedical devices as adaptive compressors and seals [38][39][40][41][42], in communication systems as microwave and radio frequency filters [43][44][45], and in automobile production as active braking systems [46][47][48]. Historically, the majority of both fundamental and applied research concerning MAEs has centered on harnessing the bulk properties of these materials. ...
A finite-element model of the mechanical response of a magnetoactive elastomer (MAE) volume element is presented. Unit cells containing a single ferromagnetic inclusion with geometric and magnetic anisotropy are considered. The equilibrium state of the cell is calculated using the finite-element method and cell energy minimization. The response of the cell to three different excitation modes is studied: inclusion rotation, inclusion translation, and uniaxial cell stress. The influence of the magnetic properties of the filler particles on the equilibrium state of the MAE cell is considered. The dependence of the mechanical response of the cell on the filler concentration and inclusion anisometry is calculated and analyzed. Optimal filler shapes for maximizing the magnetic response of the MAE are discussed.
... Alternatively, elastomeric actuators have shown potential in addressing these challenges [9]. Dielectric elastomeric actuators [9][10][11][12][13] and pneumatic actuators [9,[14][15][16][17][18][19] have demonstrated their capacity to offer both static pressure and vibrotactile feedback. ...
... Alternatively, elastomeric actuators have shown potential in addressing these challenges [9]. Dielectric elastomeric actuators [9][10][11][12][13] and pneumatic actuators [9,[14][15][16][17][18][19] have demonstrated their capacity to offer both static pressure and vibrotactile feedback. Dielectric elastomeric actuators, in particular, have exhibited potential for haptic applications, primarily due to their compactness and modularity. ...
... Alternatively, elastomeric actuators have shown potential in addressing these challenges [9]. Dielectric elastomeric actuators [9][10][11][12][13] and pneumatic actuators [9,[14][15][16][17][18][19] have demonstrated their capacity to offer both static pressure and vibrotactile feedback. Dielectric elastomeric actuators, in particular, have exhibited potential for haptic applications, primarily due to their compactness and modularity. ...
In the realm of virtual and augmented reality (VR/AR) and teleoperation applications, haptic feedback plays a role in enhancing task performance. One of the main goals of this study is to simplify haptic device hardware while improving its capacity to provide various stimuli at different intensities. In response to these challenges, this research introduces the Pneumatic Unit Cell (PUC), a soft-pneumatically driven device—a hollow silicone cylinder with the ability to provide both static pressure and vibrotactile feedback. Furthermore, Pneumatic Unit Cell's design simplicity has the potential for scalability, modularity, and the flexibility to mount the device on any part of the human body. The focus of the current paper is to study PUCs as an actuator and lay the foundation for future perceptual studies. The characterization studies encompass fabrication and verification of fabrication accuracy through dimensional measurements, characterizing PUCs under static pressure conditions (measuring free deflection and blocking force), and frequency conditions (measuring free deflection). In the static pressure conditions, we applied pressures ranging from 0 to 40 KPa to measure free deflection and from 0 to 30 KPa to measure blocking force. In the frequency conditions, we applied pressures of 10, 20, and 30 KPa, with inflation/deflation rates varying between 0.5 Hz and 100 Hz. The measurements of free deflection under static pressure conditions revealed that 0.9 mm and 1.2 mm PUCs exhibit a linear increase of free deflection with increase in inflation pressure. The results of free deflection measurements under the frequency conditions indicate a direct relationship between free deflection magnitude and applied pressure. The results also demonstrate an inverse relationship to the frequency of inflation/deflation. The characterization results demonstrate a broad range of free deflection observed under both static pressure and frequency conditions, encouraging the potential application of Pneumatic Unit Cell actuators as haptic devices.
... Less work has been done with specific attention paid to interconnection [13][14][15], packaging, leak-free operation [8,15], and scalable manufacturing production [2,3]. In particular, the integration of EGaIn interconnections with sensors and actuators holds great promise for the advancement of wearable devices [16], soft robotics [17], and biomedical applications [18]; however, in the vast majority of cases, these connections are specific to each device, and the liquid metal components cannot be repurposed or reused easily. Some recent work describes using alternative materials other than silicone rubbers for recoverable devices [19] as a means to reduce potential e-waste, but most reported designs in that work use a substantial amount of material and a multi-step recycling and separation process consisting of solvent dissolution of polymers, acid or base treatment, and either magnetic or electrochemical separation of the e-waste. ...
... Simple and effective interconnections to normal electronic components would not require substantial technical skills or expensive equipment investments. By focusing on fibre form factors, it is our hope that these systems eventually make it into smart clothing and fabrics [25][26][27][28], wearable com-puters/sensors [16], sensorized materials [29], or artificial muscles [30] for future wearable applications for soft robotic systems. This work demonstrates for the first time strategies for the continuous production of liquid metal wires and their subsequent reduction in size to create microscale features that are still compatible with standard electronics prototyping connectors. ...
... This vulnerability of the G1645 fibres to complete collapse is another reason that their use may ultimately be less desirable for stretchable electronics than first assumed. Despite these challenges, the mechanisms for creating highly stretchable and almost imperceptible strain sensors with these drawn-down wires hold great promise for the eventual integration of electrical versions of optical sensors or pneumatic controls within soft robotic systems, haptics, or wearable electronics [16], as well as damage detection and other functionalities. A simple test of repeatability was set up and shown in Figure 7. ...
We present in this work new methodologies to produce, refine, and interconnect room-temperature liquid-metal-core thermoplastic elastomer wires that have extreme extendibility (>500%), low production time and cost at scale, and may be integrated into commonly used electrical prototyping connectors like a Japan Solderless Terminal (JST) or Dupont connectors. Rather than focus on the development of a specific device, the aim of this work is to demonstrate strategies and processes necessary to achieve scalable production of liquid-metal-enabled electronics and address several key challenges that have been present in liquid metal systems, including leak-free operation, minimal gallium corrosion of other electrode materials, low liquid metal consumption, and high production rates. The ultimate goal is to create liquid-metal-enabled rapid prototyping technologies, similar to what can be achieved with Arduino projects, where modification and switching of components can be performed in seconds, which enables faster iterations of designs. Our process is focused primarily on fibre-based liquid metal wires contained within thermoplastic elastomers. These fibre form factors can easily be integrated with wearable sensors and actuators as they can be sewn or woven into fabrics, or cast within soft robotic components.
... There is a growing demand for the simultaneous engagement of multiple perception channels despite the low individual feedback quality. 57 Both comprehensive and immersive VR and AR technologies with multisensory capacities in the field of human−machine interactions have the potential for social media, entertainment, rehabilitation, and recovery applications. Thus far, many portable and compatible wearable VR and AR devices made from hydrogels have been developed to enrich the senses of the virtual world, consequently optimizing user experiences. ...
... As with epidermal electronics for sensing, technologies to simulate realistic haptic cues must conform to the skin in a comfortable manner, but with the additional requirement for individually addressing these receptors over large areas, and with spatiotemporal control of multimodal forms of vibrational and temperature stimuli. 11 The level of complexity and multifunctionality in operation demands high-performance materials, integrated in hybrid layouts that are physically skin compatible. Figure 2b shows a wireless "epidermal" VR haptic interface constructed based on the hybrid materials approach, as a first example of this concept. ...
Bioelectronic systems are emerging technologies with unique capabilities for establishing bidirectional biophysical and biochemical interfaces to soft living tissues. Applications range from tools for biomedical research on organoids and animal models to sensing and therapeutic platforms for addressing patient needs. Recent advances in materials science, materials processing techniques, and assembly/integration methods establish the foundations for progress in this area, with a growing collection of successful examples of translation into commercial products. This article summarizes our own work in this area, with an emphasis on hybrid approaches that combine both organic and inorganic materials into engineered composite structures optimized to support functional requirements, including physical/chemical levels of biocompatibility, high-performance electronic/microfluidic operation, tissue-like mechanical properties and geometries, and in some cases, fully bioresorbable designs and/or three-dimensional (3D) layouts. System-level examples that leverage these ideas span (1) epidermal platforms that probe the electrical, thermal, mechanical, and chemical properties of the skin and underlying physiological processes for diagnostic purposes; (2) implantable devices that combine sensors and therapeutic actuators under closed-loop feedback control through intimate interfaces to various tissues/organs; (3) bioresorbable electronic systems as temporary implants that support a desired operational time frame and then harmlessly degrade within the body; and (4) 3D mesoscale networks that integrate with tissue constructs across volumetric spaces for multimodal neuromodulation, sensing, and manipulation. We conclude with an overview of the current state of the field and a summary of research opportunities in hybrid materials approaches as the basis for continued advances in bioelectronics.
