Active Dressware: Wearable Kinesthetic Systems

Abstract

Artificial sensory motor systems granting the power to reach out and interact with illusory objects and granting the objects the power to resist movement or to manifest their presence are now under development in a truly wearable form using an innovative technology based on electro-active polymers. The integration of electro-active polymeric materials into wearable garments endows them with strain sensing and mechanical actuation properties. Woven active electronic components and energy storage devices now under investigation would also potentially provide all essential instrumental functions (sensor, actuator, processor, power supply) in materials and forms which could be incorporated into garments. The methodology underlying the design of haptic garments has necessarily to rely on knowledge of biological perceptual processes which is, however, scattered and fragmented. Integration of afferent and efferent neuromuscular responses and commands to build up complex functions such as kinesthesia, stereognosis and haptics is far out of reach of our present understanding. Nonetheless, use of new polymeric electroactive materials in the form of fibers and fabrics, combined with emerging biomimetic concepts in sensor data analysis, pseudomuscular actuator control and biomechanic design, may not only provide new avenues toward the realization of truly wearable kinesthetic and haptic interfaces, but also clues and instruments to better comprehend human manipulative and gestural functions. In this chapter, the biological bases which characterize sensory-motor functions in humans are summarized, focusing on their perceptual features. Biological muscle action and control are also outlined, with the purpose of providing essential information needed to analyze and design pseudomuscular actuation systems. Electroactive polymer actuators, which we are currently investigating, are then discussed with emphasis given to their unique capabilities in the phenomenological mimicking of skeletal muscle actuation. Finally, the conception, early stage implementation and preliminary testing of a fabric-based wearable interface endowed with spatially redundant strain sensing and distributed actuation are illustrated with reference to a wearable upper limb artificial kinesthesia system.