A5.2 - RoboTouch - An Artificial Skin for Human-Robot Interaction

SENSOR+TEST Conferences 2009
2009-05-26 - 2009-05-28
Congress Center Nürnberg
Proceedings SENSOR 2009, Volume I
A5 - Mechanical Sensors III
M. Fritzsche, N. Elkmann - Fraunhofer Institute for Factory Operation and Automation, Magdeburg, Germany
121 - 126


Beside the well-established robot applications in the range of industrial tasks, where the workspaces of humans and robots are strictly separated, new application areas for service and assistance robots are moving more and more into the focus of interest. Within these applications the robots are no longer banned behind strong steel fences but share a common workspace with the human being. The main advantage of such systems is to combine the flexibility and intelligence of the human being with the robots ability to fulfil monotonous tasks with high precision.
The interaction between humans and robots within a common workspace (e.g. in industrial, but also in household or laboratory environments) allows - and also often requires - physical contact between humans and robots. This human-robot interaction can bring many advantages, but it also poses a high risk potential for the human. Therefore the main task in developing such applications is to minimize the safety risk for the human.
An important contribution to this task has been made by the Fraunhofer IFF through the development of a pressure sensitive artificial skin, which will be further developed and certified as a collision detection sensor for safety applications. A patent has been applied for the sensor setup.
The sensor system is intended to be applied to robotic arms where standard collision detection sensors cannot be used. Covering the whole robot surface, the sensor system is able to capture forces affecting the sensor surface. Due to a matrix assembly of multiple sensor cells a pressure distribution may be determined with the sensor data. Through the use of intelligent postprocessing algorithms, impacts and collisions may be detected and an emergency stop signal is generated afterwards.
The measuring principle of the artificial skin sensor is based upon the pressure dependent resistance of conductive elastomeric foam. Via textile electrodes and textile ribbon cables a matrix setup is built out of single foam elements. Covered by a cladding material the sensor elements are protected against external influences. Due to this construction, consisting solely of textile materials, the sensor system is a highly durable.
As a result of the desired construction, existing problems such as reproducible coupling between electrodes and conductive foam and the protection of sensor elements against external influences could be solved.
Even though the main intention in developing the artificial skin sensor was to use it as a safety sensor for robotic applications, our experience indicates that the sensor has a wide range of possible applications including tactile input units, monitoring and survey units, measuring systems for pressure distributions and many other smart textile applications.
The first application of the sensor system is for the whole robotic system within the LiSA project, supported by the Federal Ministery of Education and Research (www.lisa-roboter.de).
Our experiences, the sensor technology itself and the ongoing development will be described in more detail within this paper.