Printing Multi‐Material Organic Haptic Actuators

Abstract

simulation training, communication, and immersive entertainment. Yet, the utility of haptics is currently limited; moreover, it is challenging to produce the large-area, distributed signals required to mimic natural touch.It would be desirable for haptic actuators to generate large ranges of forces and displacements over short time scales, in a compact form factor in the case of wearable haptics. This dynamism is required because the structures such as the skin and elements of the musculoskeletal system are highly stretchable. Moreover, they are teeming with mechanosensory neurons that can perceive sub-micron surface features and macroscale displacements, with reaction times in milliseconds. [3,5] Thus, to accommodate this dynamism and sensitivity, an exceptionally versatile suite of materials and tools is required to realize the entire range of haptic perception.Haptic perception can be divided into two parts: the tactile and kinesthetic senses. [6][7][8] The tactile sense involves the nerve endings in the skin to detect contact, texture, and vibration. The kinesthetic sense is the awareness of the body position and involves structures located in the musculoskeletal system to sense force and motion. For example, to emulate the feeling of grasping a cup, a haptic system would need to trigger both tactile and kinesthetic senses. That is, pressure would be applied on the fingers to indicate contact, and other actuators located at the joints of the fingers would stiffen to produce resistance against moving into the space occupied by the cup. In comparison to visual or auditory inputs aiming at localized organs of eyes and ears, haptic systems require distributed inputs covering the body. The complexity involved to simulate haptic signals over large area, with sufficient spatial and temporal resolution and high dynamic range, has been a considerable challenge and thus presents exciting research opportunities.Conventional micro-electromechanical system (MEMS) has been used to implement vibrational feedback, which is the most common type of haptic effect in commercial devices today. However, fabrication techniques for MEMS are catered toward micrometer length scales and hence research is still needed to scale up MEMS assembly [9,10] for large, customized human interfaces. To realize many other promising haptic modalities, new materials and processing technologies are being explored to make devices that improve haptic realism and scalability for mass manufacturing.Haptic actuators generate touch sensations and provide realism and depth in human-machine interactions. A new generation of soft haptic interfaces is desired to produce the distributed signals over large areas that are required to mimic natural touch interactions. One promising approach is to combine the advantages of organic actuator materials and additive printing technologies. This powerful combination can lead to devices that are ergonomic, readily customizable, and economical for researchers to explore potential benefits and create new haptic applications...

Attention Enhancement for Exoskeleton-Assisted Hand Rehabilitation Using Fingertip Haptic Stimulation

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