Haptic Intelligence

Optimizing a Viscoelastic Finite Element Model to Represent the Dry, Natural, and Moist Human Finger Pressing on Glass

2021

Article

hi

When a fingerpad presses into a hard surface, the development of the contact area depends on the pressing force and speed. Importantly, it also varies with the finger's moisture, presumably because hydration changes the tissue's material properties. Therefore, we collected data from one finger repeatedly pressing a glass plate under three moisture conditions, and we constructed a finite element model that we optimized to simulate the same three scenarios. We controlled the moisture of the subject's finger to be dry, natural, or moist and recorded 15 pressing trials in each condition. The measurements include normal force over time plus finger-contact images that are processed to yield gross contact area. We defined the axially symmetric 3D model's lumped parameters to include an SLS-Kelvin model (spring in series with parallel spring and damper) for the bulk tissue, plus an elastic epidermal layer. Particle swarm optimization was used to find the parameter values that cause the simulation to best match the trials recorded in each moisture condition. The results show that the softness of the bulk tissue reduces as the finger becomes more hydrated. The epidermis of the moist finger model is softest, while the natural finger model has the highest viscosity.

Award: (Honorable Mention for the Best ToH Short Paper Award, Finalist for the Best Video Presentation Award at World Haptics Conference 2021)
Author(s): Saekwang Nam and Katherine J. Kuchenbecker
Journal: IEEE Transactions on Haptics
Volume: 14
Number (issue): 2
Pages: 303--309
Year: 2021
Month: May
Day: 4
Publisher: IEEE
Department(s): Haptic Intelligence
Research Project(s): Finger-Surface Contact Mechanics in Diverse Moisture Conditions
Bibtex Type: Article (article)
Paper Type: Journal
Award Paper: Honorable Mention for the Best ToH Short Paper Award, Finalist for the Best Video Presentation Award at World Haptics Conference 2021
Digital: True
DOI: 10.1109/TOH.2021.3077549
Note: Presented at the IEEE World Haptics Conference (WHC)
PUBMED: 33945487
State: Published
Supplement: https://ieeexplore.ieee.org/abstract/document/9423563/media#media

BibTex 

@article{Nam21-TOH-Model,
  title = {Optimizing a Viscoelastic Finite Element Model to Represent the Dry, Natural, and Moist Human Finger Pressing on Glass},
  author = {Nam, Saekwang and Kuchenbecker, Katherine J.},
  journal = {IEEE Transactions on Haptics},
  volume = {14},
  number = {2},
  pages = {303--309},
  publisher = {IEEE},
  month = may,
  year = {2021},
  note = {Presented at the IEEE World Haptics Conference (WHC)},
  doi = {10.1109/TOH.2021.3077549},
  month_numeric = {5}
}