Skip to main content
Open Access Publications from the University of California

UC Berkeley

UC Berkeley Previously Published Works bannerUC Berkeley

Milliscale Features Increase Friction of Soft Skin in Lubricated Contact


Real world environments, such as kitchens, present objects covered in viscous fluids: soap, oil, water, etc. Understanding and designing for slippery and submerged contact, where fluid lubrication is present, is a continuing challenge in the robotics community. Contact area, bending stiffness, and the presence of a viscous fluid affect friction. This work focuses on milliscale features (3 to 20 mm in size) of soft urethane skin on smooth, flat surfaces. We characterize the friction of soft skins, with varying size, and therefore bending stiffness, of cylindrical features, all with the same nominal contact area. In addition, a new method of frustrated total internal reflection with dye is introduced to visualize lubricated contact. We find that a small number of milliscale fingertip features maximizes friction force in the presence of lubrication, as compared both to un-patterned and many-featured skin designs. This holds true for a robotic gripper test, when pinching glass submerged in oil.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View