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Cross-cutting Challenges - Theme 1: Interactive Discussions
Cross-cutting Challenges
California East
Body-Grounded Soft Haptics
Allison M. Okamura
(Stanford University, USA)
Abstract: Wearable haptic feedback devices for virtual reality, human-robot interaction, motion guidance, and physical support require lightweight actuators that display clearly discernible cues and potentially even large forces to the user. These goals motivate the design of a class of pneumatically actuated, body-grounded soft haptic devices. Their common feature is inflation of flexible but not stretchable thermoplastic pneumatic actuators – which can be attached to limb segments for kinesthetic feedback or directly touching the skin for tactile feedback. One example is an exomuscle, which is an inflatable device for shoulder abduction support. Designed for assistance and rehabilitation for stroke patients, the exomuscle supports the weight of the arm, offloading shoulder abductor muscles that have become erroneously coupled to elbow muscles. We constructed one type of exomuscle by reinforcing a plastic bladder with a fabric bag that is sewn to supporting straps. The bladder can then be inflated with pressurized air to provide expansive forces between the user’s torso and arm, supporting shoulder abduction. A seam acting as a hinge joint connects the exomuscle to the torso. A second example is WRAP (Wearable, Restricted-Aperture Pneumatics), which inflates a pouch with heat-sealed with switchback channels placed in direct contact with the skin, either on a held object or placed on the human body. It is capable of a variety of pulse frequencies higher and avoids sensory adaptation while delivering salient cues by exciting multiple types of mechanoreceptors. A third example is HapWRAP, A soft growing wearable haptic device that uses controlled air flow to cause an inverting plastic tube to grow out of a compact housing unit and provide a combination of directional and force feedback to a user. When activated, HapWRAP grows up and around the forearm; it loops form a temporary sleeve. After growth, WRAP-type pneumatic actuators inflate and deflate to stimulate mechanoreceptors in the skin at distinguishable locations. Future challenges in soft haptic design include potable, low cost, and quiet air supply, automated manufacturing, methods of personalization/fitting for different people, and development of real world applications demonstrating effective realism and guidance.

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Time stamp: 2019-05-20T06:29:21+02:00