FingerPrint: A 3-D Printed Soft Monolithic 4-Degree-of-Freedom Fingertip Haptic Device with Embedded Actuation

TL;DR

This paper introduces a fully 3-D printed, soft, monolithic fingertip haptic device with 4-DoF motion, leveraging origami-inspired design and embedded vacuum actuation for compact, high-force tactile feedback.

Contribution

It presents a novel 3-D printed, origami-based, soft monolithic haptic device with embedded actuation capable of multi-DoF motion and significant force output.

Findings

Achieves up to 1.3 N shear force and 7 N normal force.

Provides 4-DoF fingertip motion with compact size (40 mm x 20 mm).

Demonstrates rapid fabrication of complex wearable mechanisms using 3-D printing.

Abstract

Wearable fingertip haptic interfaces provide tactile stimuli on the fingerpads by applying skin pressure, linear and rotational shear, and vibration. Designing and fabricating a compact, multi-degree-of-freedom, and forceful fingertip haptic interface is challenging due to trade-offs among miniaturization, multifunctionality, and manufacturability. Downsizing electromagnetic actuators that produce high torques is infeasible, and integrating multiple actuators, links, joints, and transmission elements increases device size and weight. 3-D printing enables rapid manufacturing of complex devices with minimal assembly in large batches. However, it requires a careful arrangement of material properties, geometry, scale, and printer capabilities. Here we present a fully 3-D printed, soft, monolithic fingertip haptic device based on an origami pattern known as the "waterbomb" base that embeds foldable vacuum actuation and produces 4-DoF of motion on the fingerpad with tunable haptic forces (up to 1.3 N shear and 7 N normal) and torque (up to 25 N-mm). Including the thimble mounting, the compact device is 40 mm long and 20 mm wide. This demonstrates the efficacy of origami design and soft material 3D printing for designing and rapidly fabricating miniature yet complex wearable mechanisms with force output appropriate for haptic interaction.