Lateral Force on Fingertips by Traveling Waves in a Flat Structure Based on the Ultraloop

Master thesis (2023)

Authors

K.J. Renkema Mechanical Engineering

Contributors

M. Wiertlewski Human-Robot Interaction - Mechanical, Maritime and Materials Engineering (supervisor 1)
Z. Cai Human-Robot Interaction - Mechanical, Maritime and Materials Engineering (supervisor 2)
P.G. Steeneken Dynamics of Micro and Nano Systems - Mechanical, Maritime and Materials Engineering (coach)
Faculty
Mechanical Engineering
Copyright: © 2023 Koen Renkema
Traveling Waves Surface haptics Active force Flat structure
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Published Date

01-06-2023

Language

English

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Faculty

Mechanical Engineering

Abstract

Creating a lateral force on a finger touching a touch- screen can provide the sensation of a bump in the surface, and generate a pulling sensation, which could enhance the experience of operating a touchscreen. The Ultraloop, a device built to generate such a lateral force on a finger in contact, works by producing flexural traveling waves that push the finger. However, its shape is not simple to manufacture. Moreover, its shape is inconvenient to place in most touch input interfaces, which often appear in flat devices. A flat UltraLoop is proposed providing similar traveling wave force feedback, fitting the form factor of flat human-machine touch interfaces better. Furthermore, the new shape allows for manufacturing from a sheet of aluminum, using a cnc. The flat Ultraloop works by actuating two orthogonal modes at around 38k Hz, with a phase shift of 90 degrees, similarly to the Ultraloop. To validate the performance, force measurements have been conducted showing a maximum lateral force of 0.3N. Also, the influence of the normal force, phase, and finger motion on the lateral force is investigated. Lastly, we present a demo showing application of the flat Ultraloop, simulating a spring and a bump.