Fiber Optic Shape Sensing for Soft Robotics.

Isuru S. Godage,Yue Chen,Brian Rife,Kevin C. Galloway,Eric J. Barth,Emily Templeton

doi:10.1089/soro.2018.0131

Abstract

While soft material actuators can undergo large deformations to execute very complex motions, what is critically lacking in soft material robotic systems is the ability to collect high-resolution shape information for sophisticated functions such as environmental mapping, collision detection, and full state feedback control. This work explores the potential of a nearly commercial fiber optic shape sensor (FOSS) and presents the first demonstrations of a monolithic, multicore FOSS integrated into the structure of a fiber-reinforced soft actuator. In this pilot study, we report an open loop sensorized soft actuator capable of submillimeter position feedback that can detect the soft actuator's shape, environmental shapes, collision locations, and material stiffness properties.

Highlights

IntroductionSoft material robotics has captured the attention of academia,[1] industry,{ and Hollywood.{ Drawing from a highly compliant material library (i.e., elastomers and textiles), soft material robotics opens new avenues to create solutions that are closely matched to mechanical properties of natural and biological entities, enabling them to safely interface with everything from produce to people.[2,3,4] Soft material robotic systems can execute large, complex elastic deformations with simple inputs such as pressurized fluid and cables and can apply small forces over large areas to safely perform supportive,[5,6] rehabilitative,[3,4,7,8] and manipulation[9,10,11] functions
We presented new advancements in the fabrication and characterization of soft actuators with an integrated fiber optic shape sensor (FOSS)
We described enhancements to a multistep, soft actuator molding process that enables the integration of a FOSS into the body of a soft material actuator

Summary

Introduction

Soft material robotics has captured the attention of academia,[1] industry,{ and Hollywood.{ Drawing from a highly compliant material library (i.e., elastomers and textiles), soft material robotics opens new avenues to create solutions that are closely matched to mechanical properties of natural and biological entities, enabling them to safely interface with everything from produce to people.[2,3,4] Soft material robotic systems can execute large, complex elastic deformations with simple inputs such as pressurized fluid and cables and can apply small forces over large areas to safely perform supportive,[5,6] rehabilitative,[3,4,7,8] and manipulation[9,10,11] functions. Many of the soft material actuators that have been proposed have an infinite degree of freedom of motion in their passive (unpowered) state and ‘‘preferred’’. Degrees of freedom in their active state This is very different from traditional rigid-robotic systems, which typically have finite configurations defined by the joint motions and are designed to transmit large forces with high precision. We emphasize preferred degrees of freedom because soft actuators have a continuum of ‘‘joint angles’’ with a subset of the continuum preferring motion under different circumstances. External forces, collisions, and contact with obstacles can significantly alter the shape and motion of a soft actuator. To enable practical applications that can approach the precision, accuracy, and reliability of rigid robotic systems, advances in state feedback in soft material robotics systems are needed

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