2021 IEEE World Haptics Conference (WHC)
July 6-9, 2021. Montreal, CanadaFeature Quantification of Material Texture Perception
Using a Force-Displacement Relationship*
Yoichi Yamazaki1 , Masataka Imura1 , Masashi Nakatani2 , Shin Osanai2 , Noriko Nagata1 and Hiroya Tanaka2

250

III. VALIDATION OF FDDF (STROKE)
To show the quantification validity using FDDF (Stroke),
we evaluated whether the tactile characteristics of fabrics canbe expressed by FDDF (Stroke). We measured the height

10[mm]0

where Nl is the analysis line number, x is the line representedby the index l, and F is the function that calculates theone-dimensional sequence power spectrum. Moreover, theconverted height map ĥ is calculated with the following:ĥ = g(h, d),where g is a function that selectively extracts informationfrom the surface texture up to a depth d, which is not
perceived by the skin when stroking a surface texture. ĥ has
information contributing to tactile perception selectively.

FDDF(Stroke)

20Fig. 1.

150-150.1

0Frequency [cycle/mm]

10

Example of FDDF (Stroke).

Factor Score [-]1l=10-1Fig. 2.

F1 (fine-textured feeling)
Roughness
F2 (moist feeling)
F3 (hardness)

-2-3

12

34

68

9

Symbol number of Sailcloth

101179A

Relationship between fabric structure and tactile perception.

IV. CONCLUSIONSWe proposed FDDF (Stroke) as a novel feature thathas a high affinity with both the physical properties andsensibility values of products. Furthermore, we demonstrated
the validity of FDDF (Stroke) for expressing the tactile
perception of fabric. In the future, the quantification ofvarious materials with FDDF (Stroke) will make it possible
to realize production based on sensibility values.

*This work was partially supported by JST COI Grant Number JPMJCE1314.
1 School of Engineering / Kwansei Gakuin Institute of Kansei Value
Creation, Kwansei Gakuin University, Sanda, Hyogo, Japan. {m.imura,y-yamazaki, nagata}@kwansei.ac.jp
and Information Studies, Keio
Kanagawa,Japan{mn2598,htanaka}@sfc.keio.ac.jp
978-0-7381-2491-9/21/$31.00 ©2021 IEEE

10180We found the height map feature that constitutes the tactile
perception by the study of plastic textures [3], and defined thefeature as FDDF (Stroke). The feature is a 23-dimensional
vector and is calculated with the following:
Nl1 XF(ĥ(x(l))),FDDF(Stroke) =Nlof Environment
5322
EndoHeight [μm]II. FDDF IMPLEMENTATION

2 Faculty
University,

Hight-map

0500

The force-induced displacement distribution function(FDDF) was defined as a conceptual function that has highexplain-ability for both physical features and sensibility
values (ex. comfortable feeling, luxury feeling ) [1, 2]. Thisfunction realizes the production based on sensibility values;
however, it is not clear how the function is implemented.
In this study, we proposed the FDDF (Stroke) as the FDDF
implementation regarding the texture perception by stroking.
Moreover, we evaluated the validity of the implemented
FDDF (Stroke) by using fabrics of JIS L3402 standard.

Power [dB]I. INTRODUCTION

maps for 10 sailcloth types (Takeyari Co., Ltd.) using 3D
measurement system (Keyence Co. Ltd., VR-5000), andcalculated the features for each height map. An example ofthe measured height map and the calculated FDDF (Stroke)
is shown in Fig. 1. The relationship between the tactile
perception predicted by FDDF (Stroke) using the tactile
prediction model [3] and the type of sailcloth is shown inFig. 2. The type of sailcloth is standardized by JIS L3402
and expressed as a numeric symbol. In general, roughness
and hardness decrease as the number of numeric symbol
increases. We confirmed that FDDF (Stroke) is effective forrepresenting the tactile texture of hard fabrics, because thetactile tendency of sailcloth is well represented.

[mm]

Abstract— The force-induced displacement distribution function (FDDF) is a physical quantity with a high degree offamiliarity with product production parameters and sensibility
values. In this study, we proposed FDDF (Stroke) as the texture
perception by stroking FDDF implementation. Moreover, weshowed that FDDF (Stroke) has a highly expressive tactile
perception capability for hard materials.

1157

R EFERENCES[1] M. Nakatani et al., “A 3D-printed haptic material library for quantifying the force-displacement relationship,” IEEE World Haptics
Conference 2021, Work-in-Progress Papers (accepted).
[2] M. Imura et al., “Feature quantification of material softness perception using the force-displacement relationship,” IEEE World Haptics
Conference 2021, Work-in-Progress Papers (accepted).
[3] Y. Yamazaki et al., “Investigation of a method for creating tactile
texture resonating with ‘Kansei’,” Proceedings of the 2018 JSAE
Annual Congress (Spring), 137, 2018.