A bio-mimetic fingertip that detects force and vibration modalities and its application to surface identification

Tactile sensing is an important modality for robots that interact with the environment. It enables the collection of physical information of the environment such as softness, texture and temperature. Especially, object manipulation strongly depends upon tactile sensing. Humans recognize object's properties by touching the manipulated object. Thus, humanoid robots and artificial prosthetics require tactile sensing when they manipulate objects. In this paper, a biomimetic tactile fingertip for humanoid robots is presented. This soft fingertip has three commercially available accelerometers and seven force sensors in two layers of polyurethane and is able to detect micro-vibration and force modalities. The fingertip has a bone, covered with polyurethane rubber layer that mimics tissue and another polyurethane layer with a different hardness, that mimics human skin layer. The design, fabrication steps and the data processing method are stated. Furthermore the static force distribution map and the initial test data of the surface identification test are presented. Initial tests show promising results that the system is capable of detecting micro-vibrations and force modalities. In addition it has the capability of identifying different types of surface textures by comparing accelerometer and force sensor signals.