FlatLoop

Low-Profile Active Force Feedback Device Using Traveling Waves

Conference Paper (2025)
Author(s)

Zhaochong Cai (TU Delft - Mechanical Engineering)

Koen Renkema (ElaadNL)

Michaël Wiertlewski (TU Delft - Mechanical Engineering)

Research Group
Human-Robot Interaction
DOI related publication
https://doi.org/10.1109/WHC64065.2025.11123224 Final published version
More Info
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Publication Year
2025
Language
English
Research Group
Human-Robot Interaction
Pages (from-to)
527-533
Publisher
IEEE
ISBN (electronic)
9798331533533
Event
2025 IEEE World Haptics Conference, WHC 2025 (2025-07-08 - 2025-07-11), Suwon, South Korea
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31
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Abstract

Active surface haptic devices can guide users by pushing and pulling their fingers. These devices generate active forces directly on the fingertip using resonant traveling waves. Modulating the amplitude of the wave and its direction allows fine control over the force applied to the fingertip, which in turn can be used to create compelling tactile sensations such as elastic potential fields that attract or repel the finger and emulate the feel of curved surfaces. However, existing designs are bulky, with ring-shaped cavities unsuitable for thin consumer electronics. This paper introduces flatLoop, a compact surface haptic device with a height of just 5 mm. It uses a planar aluminum structure with two straight and two curved beams along which flexural waves travel. The thickness of the curved beams varies, steering the wave propagation around corners. Experimental results demonstrate that flatLoop generates uniform traveling waves and produces lateral forces of up to 0.3 N on an 80 × 30 mm2 flat surface. This innovative design can deliver rich tactile effects in a compact form, ideal for applications like rendering a flat keyboard where users can feel the shape of keys. This design can facilitate the integration of technology into consumer electronics.

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