TacTip

A biomimetic optical tactile fingertip from the Bristol Robotics Laboratory that uses a camera to watch internal marker pins move.

TacTip is a family of optical tactile sensors developed at the Bristol Robotics Laboratory in the UK, with the earliest version published around 2009. It mimics the dermal papillae structure beneath human fingertip skin: the outside is a soft, hemispherical skin, the inside is lined with rows of small pins tipped with white markers, the space between is filled with transparent gel, and a camera sits inside. When the finger touches an object, the skin deforms and moves the pins with it; the camera tracks the displacement of these markers, from which contact location, shape, edges, and shear direction can be inferred. Most of its parts can be 3D printed, keeping cost low, and it has since spawned a “TacTip family” of different sizes and shapes that can be mounted on robotic fingers or grippers. Unlike GelSight, which photographs surface texture under lighting, TacTip follows a marker-tracking approach.

ExampleA TacTip mounted on the end of a robot arm is slid along an object’s contour; the displacement of its marker pins reveals the direction of the edge, letting it trace out the object’s outline.

Also called

Biomimetic Optical Tactile Fingertip, TacTip Family

Related

Vision-Based Tactile Sensor · Marker Tracking · GelSight · Tactile Sensor · Slip Detection · Tactile Image

Sources

The TacTip Family: Soft Optical Tactile Sensors with 3D-Printed Biomimetic Morphologies (Ward-Cherrier et al., Soft Robotics 2018)