Untethered Feel‐Through Haptics Using 18‐µm Thick Dielectric Elastomer Actuators

Abstract

Head-mounted displays for virtual reality (VR) and augmented reality (AR) allow users to see highly realistic virtual worlds. The wearable haptics that enable feeling and touching these virtual objects are typically bulky, tethered, and provide only low fidelity feedback. A particularly challenging type of wearable human-machine interface is feel-through haptics: ultra-thin wearables so soft as to be mechanically imperceptible when turned off, yet generating sufficient force when actuated to make virtual objects feel tangible, or to change the perceived texture of a physical object. Here, 18 µm thick soft dielectric elastomer actuators (DEA), directly applied on the skin, reports rich vibrotactile feedback generation from 1 Hz to 500 Hz. Users correctly identifies different frequency and sequence patterns with success rates from 73 to 97% for devices applied on their fingertips. An untethered version weighing only 1.3 grams allowed blindfolded users to correctly identify letters by "seeing" them through their fingers. The silicone-based DEA membrane is mechanically transparent, enabling wearable haptics for the many applications where hand dexterity is critical. The feel-through DEA can be placed in array format anywhere on the body.

Intelligent Soft Surgical Robots for Next‐Generation Minimally Invasive Surgery

“…The surface texture, topography, stiffness, deformation, applied force, and other desired information of the internal organs of the patient can be measured and fed back by the integrated sensing system of the surgical tools and then transmitted to the surgeon through tactile reproduction provided by the soft actuator array. Some researches using soft robotic technologies for haptic feedback have emerged in recent years, and a recent review of them can be found in the study by Yin et al [408] Common haptic feedback methods based on mechanical stimulation include vibrotactile stimulation, [409,410] normal pressing, [411,412] and skin stretch, [413,414] and the introduction of soft technologies can achieve safe, compact, and lightweight system integration as well as good simulation of tactile sensation of soft organs.…”

Wearable Actuators: An Overview

“…For wearable assistance in particular, research has mainly explored communication and rehabilitation. As haptic feedback is an important part of electronic textiles and wearable technologies, integrating DE tactile actuators into wearable systems through haptic sensation has been a rising field of interest attributed to material softness, small size, ease of fabrication, and adaptability compared to traditional rigid motors with fixed frequencies [98]. A crucial factor for effective sensing of haptic cues is skin perceptibility, which means the output force and resonance frequency should reach perceivable levels and depends on both human and device factors, such as placement on bodies and material stiffness [98,99].…”

“…As haptic feedback is an important part of electronic textiles and wearable technologies, integrating DE tactile actuators into wearable systems through haptic sensation has been a rising field of interest attributed to material softness, small size, ease of fabrication, and adaptability compared to traditional rigid motors with fixed frequencies [98]. A crucial factor for effective sensing of haptic cues is skin perceptibility, which means the output force and resonance frequency should reach perceivable levels and depends on both human and device factors, such as placement on bodies and material stiffness [98,99]. For example, typically finger tips are ideal positions of tactile devices due to their higher sensitivity than other parts like arms, and usually susceptible to a force threshold around 30mN depending on the fingers [100].…”

“…For example, typically finger tips are ideal positions of tactile devices due to their higher sensitivity than other parts like arms, and usually susceptible to a force threshold around 30mN depending on the fingers [100]. Hence, one of the main goals in the current development of DEA haptic wearable interfaces is to generate large force and displacement outputs at such a small (millimeter) scale [98,101]. Meanwhile, as human contact is involved, the design of wearable haptic interfaces using DEAs needs to take into account various aspects such as compactness, weight, comfort, safety, etc.…”

“…Most current designs of wearable haptics have leveraged the out-of-plane deformation of diaphragm/membrane [98,102] and linear displacement of rolled multilayer [103] configurations, as well as the hydraulic amplification with liquid coupling effect [101]. Multilayered PDMS membranes coated by AgNWs electrodes with a perforated polymeric frame support were able to generate an output force up to 255 mN and a protrusive displacement of 650μm (Figure 12a) [14].…”