A review of fingerpad contact mechanics and friction and how this affects tactile perception

Abstract

In the sliding contact between the fingerpad and a rough surface when touching a product’s surface, friction plays a role in the perception of roughness, slipperiness and warmth. For product engineers who aim to control and optimize the sensorial properties of a product surface interacting with the skin, it is essential to understand this frictional behaviour. However, the friction of skin is yet poorly understood. The variation that is observed within or between skin friction studies can be assigned to gender, age and orientation of the finger. Analysing data collected from literature shows some consistent trends. The coefficient of friction increases considerably with increasing hydration level of the skin, due to softening of the top layer of the skin. The coefficient of friction of the fingerpad decreases with normal load to a constant value, which can be attributed to effects of normal adhesion and the deformation behaviour of the fingerpad. There is no consistent effect of velocity on the coefficient of friction. Friction decreases with increasing R_a roughness. When the R_a roughness increases further, the contribution of deformation causes an increase in the friction after which it remains constant. Some influence of the finishing method is reported. The type of material has a smaller influence than the surface roughness of the sample or the condition of the skin. Even though the coefficient of friction of the fingerpad shows some consistent trends, examining the friction behaviour at a more detailed level might explain the contribution of friction to tactile perception. The measuring signal contains relevant information and should be analysed thoroughly as opposed to taking the average coefficient of friction of the steady state part of the signal. Future work should involve the study of local friction behaviour at the scale of the surface roughness.

Keywords

Skin fingerpad tactile perception friction tribology

Get full access to this article

View all access options for this article.

References

Karana

Hekkert

Kandachar

. Meanings of materials through sensorial properties and manufacturing processes. Mater Des 2009; 30: 2778–2784.

Chen

Barnes

Childs

THC

. Materials’ tactile testing and characterisation for consumer products’ affective packaging design. Mater Des 2009; 30: 4299–4310.

Barnes

Childs

THC

Henson

. Surface finish and touch–a case study in a new human factors tribology. Wear 2004; 257: 740–750.

Childs

THC

Henson

. Human tactile perception of screen-printed surfaces: self-report and contact mechanics experiments. Proc IMechE, Part J: J Engineering Tribology 2007; 221: 427–441.

Darden

Schwartz

. Investigation of skin tribology and its effects on the tactile attributes of polymer fabrics. Wear 2009; 267: 1289–1294.

Skedung

Danerlöv

Olofsson

. Tactile perception: finger friction, surface roughness and perceived coarseness. Tribol Int 2011; 44: 505–512.

Schreiner

Rechberger

Bertling

. Haptic perception of friction–correlating friction measurements of skin against polymer surfaces with subjective evaluations of the surfaces’ grip. Tribol Int 2013; 63: 21–28.

Bergmann Tiest

. Tactual perception of material properties. Vision Res 2010; 50: 2775–2782.

Hamilton

. Explicit equations for the stresses beneath a sliding spherical contact. Proc IMechE, Part C: J Mechanical Engineering Science 1983; 197: 53–59.

10.

Derler

Gerhardt

L-C

. Tribology of skin: review and analysis of experimental results for the friction coefficient of human skin. Tribo Lett 2011; 45: 1–27.

11.

Verrillo

Bolanowski

Checkosky

. Effects of hydration on tactile sensation. Somatosens Mot Res 1998; 15: 93–108.

12.

H-N

Jones

. Contribution of thermal cues to material discrimination and localization. Percept psychophys 2006; 68: 118–128.

13.

Ashby

Johnson

. Materials and design – the art and science of material selection in product design, Oxford: Elsevier, 2006.

14.

Van der Heide

Schipper

. On the frictional heating in single summit contacts: towards failure at asperity level in lubricated systems. J Tribol 2004; 126: 275–280.

15.

Smith

Chapman

Deslandes

. Role of friction and tangential force variation in the subjective scaling of tactile roughness. Exp Brain Res 2002; 144: 211–223.

16.

Bergmann Tiest

Kappers

AML

. Haptic and visual perception of roughness. Acta Psychol 2007; 124: 177–189.

17.

Hollins

Bensmaïa

. The coding of roughness. Can J Exp Psychol 2007; 61: 184–195.

18.

Taylor

Lederman

. Tactile roughness of grooved surfaces: a model and the effect of friction. Percept Psychophys 1975; 17: 23–36.

19.

Lederman

. The perception of surface roughness by active and passive touch. Bull Psychonomic Soc 1981; 18: 253–255.

20.

Hollins

Bensmaïa

Washburn

. Vibrotactile adaptation impairs discrimination of fine, but not coarse, textures. Somatosens Mot Res 2001; 18: 253–262.

21.

Stevens

Harris

. The scaling of subjective roughness and smoothness. J Exp Psychol 1962; 64: 489–494.

22.

Kawasoe

Kakizawa

Shimizu

. Tribology in the hair surface and tactile perception. Tribol Online 2008; 3: 127–130.

23.

Liu

Yue

Cai

. Quantifying touch-feel perception: tribological aspects. Meas Sci Technol 2008; 19: 084007–084007.

24.

Whitehouse

Archard

. The properties of random surfaces of significance in their contact. Proc R Soc London. Ser A Math Phys Sci 1970; 316: 97–121.

25.

Masen

. A systems based experimental approach to tactile friction. J Mech Behav Biomed Mater 2011; 4: 1620–1626.

26.

Johnson SA, Gorman DM, Adams MJ, et al. The friction and lubrication of human stratum corneum. In: Dowson D and Taylor CM (eds) Thin films in tribology, Proceedings of the 19th Leeds–Lyon symposium on tribology, Institute of Tribology, University of Leeds, UK, vol. 25, 1993, pp.663–672.

27.

Adams

Briscoe

Johnson

. Friction and lubrication of human skin. Tribol Lett 2007; 26: 239–253.

28.

Bowden

Tabor

. The friction and lubrication of solids, Oxford: Cambridge University Press, 1950.

29.

Cua

Wilhelm

Maibach

. Skin surface lipid and skin friction: relation to age, sex and anatomical region. Skin Pharmacol 1995; 8: 246–251.

30.

Mavon

Zahouani

Redoules

. Sebum and stratum corneum lipids increase human skin surface free energy as determined from contact angle measurements: a study on two anatomical sites. Colloids Surf B Biointerfaces 1997; 8: 147–155.

31.

Gerhardt

L-C

Lenz

Spencer

. Skin-textile friction and skin elasticity in young and aged persons. Skin Res Technol 2009; 15: 288–298.

32.

Gerhardt

L-C

Schiller

Müller

. Fabrication, characterisation and tribological investigation of artificial skin surface lipid films. Tribol Lett 2009; 34: 81–93.

33.

Hendriks

Franklin

. Influence of surface roughness, material and climate conditions on the friction of human skin. Tribol Lett 2009; 37: 361–373.

34.

Greenwood

Tabor

. The friction of hard sliders on lubricated rubber: the importance of deformation losses. Proc Phys Soc 1958; 71: 989–1001.

35.

Flynn

Taberner

Nielsen

. Measurement of the force-displacement response of in vivo human skin under a rich set of deformations. Med Eng Phys 2011; 33: 610–619.

36.

Jachowicz

McMullen

Prettypaul

. Indentometric analysis of in vivo skin and comparison with artificial skin models. Skin Res Technol 2007; 13: 299–309.

37.

Boyer

Laquièze

Le Bot

. Dynamic indentation on human skin in vivo: ageing effects. Skin Res Technol 2009; 15: 55–67.

38.

Yuan

Verma

. Measuring microelastic properties of stratum corneum. Colloids Surf B Biointerfaces 2006; 48: 6–12.

39.

Tomlinson

Carré

Lewis

. Human finger contact with small, triangular ridged surfaces. Wear 2011; 271: 2346–2353.

40.

Spurr

. Fingertip friction. Wear 1976; 39: 167–171.

41.

Dinç

Ettles

Calabrese

. Some parameters affecting tactile friction. J Tribol 1991; 113: 512–517.

42.

Sasada T. The friction of human skin. In: Proceedings of the 21st Biotribology Symposium, JSME, Fukuoka, 2000, pp. 46–52.

43.

Gee

Tomlins

Calver

. A new friction measurement system for the frictional component of touch. Wear 2005; 259: 1437–1442.

44.

Tomlinson

Lewis

Carré

. The effect of normal force and roughness on friction in human finger contact. Wear 2009; 267: 1311–1318.

45.

Skedung

Danerlöv

Olofsson

. Finger friction measurements on coated and uncoated printing papers. Tribol Lett 2010; 37: 389–399.

46.

Derler

Süess

Rao

. Influence of variations in the pressure distribution on the friction of the finger pad. Tribol Int 2013; 63: 14–20.

47.

Hertz

. Über die Berührung fester elastischer Körper. J für die reine und angewandte Math 1882; 92: 156–171.

48.

Johnson

. Contact mechanics, Cambridge: Cambridge University Press, 1999.

49.

Van Kuilenburg

Masen

Van der Heide

. Contact modelling of human skin: what value to use for the modulus of elasticity? Proc IMechE, Part J: J Engineering Tribology 2013; 227: 347–359.

50.

Kinoshita

Bäckström

Flanagan

. Tangential torque effects on the control of grip forces when holding objects with a precision grip. J Neurophysiol 1997; 78: 1619–1630.

51.

Tomlinson SE. Understanding the friction between human fingers and contacting surfaces. PhD thesis, The University of Sheffield, 2009.

52.

Warman

Ennos

. Fingerprints are unlikely to increase the friction of primate fingerpads. J Exp Biol 2009; 212: 2016–2022.

53.

Tomimoto

. The frictional pattern of tactile sensations in anthropomorphic fingertip. Tribol Int 2011; 44: 1340–1347.

54.

Maeno

Kobayashi

Yamazaki

. Relationship between the structure of human finger tissue and the location of tactile receptors. JSME Int J Ser C 1998; 41: 94–100.

55.

Nakazawa

Ikeura

Inooka

. Characteristics of human fingertips in the shearing direction. Biol Cybern 2000; 82: 207–214.

56.

Soneda T and Nakano K. Investigation of the vibration detectability of human fingers supported by the observation of contact zones. In: Proceedings of the 2nd international conference on advanced tribology, Singapore, 2008, paper no. iCAT288.

57.

André

Lévesque

Hayward

. Effect of skin hydration on the dynamics of fingertip gripping contact. J R Soc Interface 2011; 8: 1574–1583.

58.

Liu

Lewis

. Feasibility of using optical coherence tomography to study the influence of skin structure on finger friction. Tribol Int 2013; 63: 34–44.

59.

Derler

Gerhardt

L-C

Lenz

. Friction of human skin against smooth and rough glass as a function of the contact pressure. Tribol Int 2009; 42: 1565–1574.

60.

Derler

Rotaru

G-M

. Stick-slip phenomena in the friction of human skin. Wear in press.

61.

Soneda

Nakano

. Investigation of vibrotactile sensation of human fingerpads by observation of contact zones. Tribol Int 2010; 43: 210–217.

62.

Pailler-Mattéi

Pavan

Vargiolu

. Contribution of stratum corneum in determining bio-tribological properties of the human skin. Wear 2007; 263: 1038–1043.

63.

Cua

Wilhelm

Maibach

. Frictional properties of human skin: relation to age, sex and anatomical region, stratum corneum hydration and transepidermal water loss. Br J Dermatol 1990; 123: 473–479.

64.

Gerhardt

L-C

Strässle

Lenz

. Influence of epidermal hydration on the friction of human skin against textiles. J R Soc Interface 2008; 5: 1317–1328.

65.

Kwiatkowska

Franklin

Hendriks

. Friction and deformation behaviour of human skin. Wear 2009; 267: 1264–1273.

66.

Tomlinson

Lewis

Liu

. Understanding the friction mechanisms between the human finger and flat contacting surfaces in moist conditions. Tribol Lett 2011; 41: 283–294.

67.

Pasumarty

Johnson

Watson

. Friction of the human finger pad: influence of moisture, occlusion and velocity. Tribol Lett 2011; 44: 117–137.

68.

Ramalho A, Silva CL, Pais AACC, et al. In vivo friction study of human palmoplantar skin against glass. In: Proceedings of Nordtrib 2006, the 12th Nordic tribology symposium, Denmark, 2006.

69.

Derler

Schrade

Gerhardt

L-C

. Tribology of human skin and mechanical skin equivalents in contact with textiles. Wear 2007; 263: 1112–1116.

70.

Savescu

Latash

Zatsiorsky

. A technique to determine friction at the fingertips. J Appl Biomech 2008; 24: 43–50.

71.

Seo

Armstrong

. Friction coefficients in a longitudinal direction between the finger pad and selected materials for different normal forces and curvatures. Ergonomics 2009; 52: 609–616.

72.

Han

H-Y

Shimada

Kawamura

. Analysis of friction on human fingers and design of artificial fingers. In: Proceedings of the 1996 IEEE international conference on robotics and automation, Minneapolis, MN, 22–28 April 1996; vol. 4: pp.3061–3066.

73.

Fagiani

Massi

Chatelet

. Contact of a finger on rigid surfaces and textiles: friction coefficient and induced vibrations. Tribol Lett 2012; 48: 145–158.

74.

Czichos

. Tribology: a systems approach to the science and technology of friction, lubrication and wear, Amsterdam: Elsevier, 1978.

75.

Tomlinson

Lewis

Ball

. Understanding the effect of finger-ball friction on the handling performance of rugby balls. Sports Eng 2009; 11: 109–118.

76.

Tomlinson

Lewis

Carré

. Human finger friction in contacts with ridged surfaces. Wear 2013; 301: 330–337.