Robots without industrial barriers

Industrial safety regulations permit contact between people and robots only under certain conditions, given the risk of injury to humans. However, researchers are working on ways to collaborate and define workplaces and safe zones that would help avoid conflict between humans and robots. The ViERforES project, being carried out by researchers at the Fraunhofer Institute for Factory Operation and Automation (IFF), is one such effort.

This safety system employs conventional projectors and cameras mounted on the ceiling. A distinctive feature of the system is that it projects monitored safe zones directly on a floor or wall. The projected beams produce visible lines in the work area. Thus, humans recognise the safe zone and know how close they are to a robot. The camera immediately detects any intrusion in the safe zone by an individual, since the projected lines are disrupted. The robot decelerates instantly. Optical and acoustic warning signals can also be generated. Another distinctive feature is the variability of the marked areas' position and size and the capability to give them any shape, including a circle and a rectangle.

“Since we employ common standard components, our system can be installed cost-effectively. The projector and the camera are calibrated and synchronised with each other,” says Norbert Elkmann, Robotic Systems Business Unit Manager, Fraunhofer IFF. When a larger area has to be monitored, the system can be extended with additional projectors and cameras.

The monitoring system operates with modulated light. It offers reliability, even under the effects of external light like sunlight and resulting shadows. The current, purely camera-based space monitoring systems operate independently of external light only to a limited extent, says Elkmann. Experts can combine this system with robot controls and thus, dynamically modify danger and safe zones.

Elkmann and his team have filed a patent for this system, of which a prototype already exists. The potential applications of the projection and the camera-based system are not limited to safe human-robot interaction alone. Other spaces in which safety is relevant can also be monitored.