Soft robotics | 2019
Closed-Loop Haptic Feedback Control Using a Self-Sensing Soft Pneumatic Actuator Skin.
Abstract
In this article, we achieve a closed-loop control over haptic feedback, first time for an entirely soft platform. We prototyped a novel self-sensing soft pneumatic actuator (SPA) with soft strain sensors, called SPA-skin, which withstands large multiaxial strains and is capable of high-frequency sensing and actuation. To close-loop control the haptic feedback, the platform requires a cohesively integrated system. Our system consists of a stretchable low profile (<500\u2009μm) SPA and an ultra-compliant thin-metal film strain sensor that create a novel bidirectional platform for tactile sensing via force-tunable vibratory feedback. With this prototype, we demonstrated control of the actuator shape in real time up to 100\u2009Hz at output forces up to 1\u2009N, maintained under variable mechanical loadings. We further characterized the SPA-skin platform for its static and dynamic behavior over a range of actuation amplitudes and frequencies as well as developed an analytical model of this system to predict the actuator inflation state only using the embedded sensor s resistance. Our SPA-skin is a multifunctional multilayer system that can readily be implemented as a high-speed wearable bidirectional interface for contact sensing and vibrotactile feedback.