Tactile Sensors

Sensors from Bielefeld bring the sense of touch to robots

Opening a jar cap, pressing a light switch in the darkness, or peeling an egg – humans perform all these tasks effortlessly. However, these activities require complex sensory-motor skills and the sense of touch, abilities that most of today’s robots do not have. Researchers at the Cluster of Excellence Cognitive Interaction Technology (CITEC) are innovating tactile sensors and corresponding processing algorithms to fill this gap. During the past ten years, they have developed a plethora of tactile sensors.

Tactile Array
The array provides 16 x 16 tactile sensing elements on a flat 8 cm x 8 cm PCB, measuring applied normal forces. Multiple modules can be combined into a larger surface to form e.g. a tactile-sensitive table to measure interaction forces. The unique feature of this sensor is its high frame rate of up to 1.8 kHz, which allows for incipient slip detection and enables autonomous grasp-force adaptation.




Tactile Fingertips and Fingernails
A miniaturized version of the tactile sensing array, fitted to the 3D shape of a fingertip, provides twelve sensing elements. An intelligent processing algorithm can determine the position, amount, and the direction of applied forces. Having equipped all ten fingers of the robot hands with these sensors, they can react to unforeseen environmental contacts notice failures, and grasp more robustly.
Humans use their fingernails to pick up small or flat objects, like a coin or a sheet of paper. CITEC’s active fingernail enables robot hands to do this too, by using miniaturized barometer and accelerometer sensors.



Tactile Data Glove and Prosthetics Sensors
Fabric-based sensors are used to flexibly cover larger surfaces, thus forming a “robot skin.” A tactile-sensitive glove allows inter­action forces to be measured when humans handle objects. This provides valuable information to better understand sensory-motor control processes during human manipulation.
The same technology was used to provide tactile sensing to the iLimb prosthetics hand from Touch Bionics, which helps amputees to regain their sense of touch.




Dr. Robert Hascke
Bielefeld University
Cluster of Excellence Cognitive Interaction Technology (CITEC)
Telephone: 0521 106-12122
Email: rhaschke@techfak.uni-bielefeld.de