Low Cost, Easily Manufactured, Highly Flexible Strain and Touch Sensitive Fiber for Robotics Applications
Christian Diaz Herrera, Srushti Raste, Simin Liu, Miles Modeste, Jiyang (Patton) Yin, Katelyn McCall, Yuxing Jared Yao, Roopkamal Chahal, Simon Chidley, Trung Ha, T. David Westmoreland, Sonia Roberts
AI summary
Problem
Existing robotic strain and touch sensors are often expensive, require complex manufacturing equipment, or are inaccessible to DIY makers and under-resourced researchers.
Approach
The authors developed a simple manufacturing method using only commercial conductive thread and silicone tubing, characterizing the resulting fiber's resistive strain and capacitive touch/near-field sensing capabilities.
Key results
- Manufacturing process using <$5 materials in under 2 minutes
- Resistive strain sensing with a gauge factor of 0.28 at 30% strain
- Capacitive touch and near-field sensing via hand-knitted electrode patches
- Demonstrated functionality in assistive gloves, robotic straps, and robot arm tracking
Why it matters
Provides an accessible, repairable, and highly flexible sensing solution for DIY makers, educators, and under-resourced robotics developers.
Abstract
Existing stretch and touch sensors for robots are generally expensive with respect to at least one of material costs, required manufacturing equipment, or manufacturing time. We present and experimentally characterize a conduc- tive fiber made using only inexpensive commercial off-the- shelf parts (conductive thread at $0.07/ft, silicone tubing at $0.94/ft) and tools (loop-style needle threader at $2), which can be manufactured quickly (20 cm length in 2 minutes.) We demonstrate its use as a resistive strain sensor with three applications: Triggering a grasp in a pneumatically actuated assistive finger, sensing the pose of a pneumatically actuated robotic strap, and estimating the pose of a flexible solid. We also demonstrate that it can be used as a capacitive sensor with two applications: First, as a touch sensor which triggers a commercial robot arm to move, and second, as a near-field sensor enabling the robot arm to follow a moving hand. The capacitive sensors are knitted, showcasing the high flexibility of the fiber. We discuss methods for improving manufacturing scalability and their cost trade-offs. Finally, we demonstrate a method for repairing a cut fiber.