Robot skin senses co-workers' presence

May 19, 2017 // By Julien Happich
During the robotics exhibition and conference Innorobo 2017 held in Paris, Fogale Robotics, a new branch of high tech equipment provider Fogale Nanotech was showcasing a novel robot skin concept aimed at securing collaborative robots (cobots).

In one demonstration, a plastic arm covered with a shirt sleeve could accurately and dynamically detect human proximity from about 20cm away and every transition up to localized touch.

In another demonstration, an articulated robot arm covered in textile was turning around as if performing a series of complex tasks. When sensing an operator's hand in close proximity, the robot immediately slowed down and stopped, avoiding collision. A gentle tap on the robot's arm resumed operation.

Company leaflets on the stand marketed this as Fogale's Sensitive Surfaces Technology, applicable to all geometries and combining 3D detection with multi-touch and multi-pressure capabilities.

During a brief interview with eeNews Europe, Fogale Nanotech's CTO, Didier Rozière revealed that hidden under the shirt sleeve were small metallized electrodes, and Fogale's readout electronics to support high precision absolute capacitive measurements.

"Today, there are no truly collaborative robots ", argued Rozière.

"Robots are still seen as potentially too dangerous, they are caged-up or equipped with laser barriers that stop all operations when breached. There are camera-based solutions but those can suffer from blind spots as the robot moves around. Meanwhile, installing and certifying safety laser barriers is very costly" he told eeNews Europe, adding that in France, 90% of robots are secured with that added safety feature requiring third party certification experts.

"What we are showing is a skin concept that is an easy retro-fit for robots. In essence, it could be as simple as putting a sleeve of specialized fabric over the robot arm, or our technology could be integrated by robot OEMs, directly under the robot's plastic or rubber skin" said Rozière, "with such a sensitive skin, a robot could not only avoid collision with an operator but could also adapt its trajectory in real time so as to carry on with its task. You could even envisage different interaction scenarios, like pushing gently the robot's arm with a finger, for fine adjustments that wouldn't require a full stop, or being more forceful by grabbing a whole section of the arm to impose a full stop or even a recoil".

So how does the technology work?

"We have the know-how to measure very small values of absolute capacitance across a large number of electrodes, so that in effect we obtain a near-field 3D image of the robot's surroundings", explained the CTO, hinting that achieving this level of measurement precision tens of centimetres away requires a lot of analogue expertise. A few years ago, this sort of very accurate 3D capacitive sensing was already promoted among smartphone OEMs by Fogale Nanotech in a short Youtube video titled "Sensation Technology", it has yet to be adopted by leading smartphone manufacturers.