Today, robots can be found in all modern factories. They support people by lifting heavy loads, screwing together individual parts and performing precise movements. But anyone who gets too close to a robot puts themselves in danger because, with its strong arms, it can seriously hurt humans. The working areas of robots are therefore usually separated from those of humans by protective fences.

A research team led by mechanical engineer Rüdiger Hornfeck now wants to develop pliable articulated robots that enable humans to work in direct cooperation with robots. The researchers have taken the animal world as a model and transferred functional mechanisms from spider legs to the robot.

The special feature of spider legs is that they are only equipped with a flexor muscle, but not with an extensor muscle. To move around, the spider pumps a bodily fluid into its legs, which leads to the stretching of the limbs. This bodily fluid also ensures that the spider legs are extremely pliable and spring back at the slightest touch.

In constructing the articulated robot, the researchers are guided by the anatomy of the spider leg: for example, the robot consists of several limbs that are covered with a plastic shell. The individual limbs are connected to each other with an expandable plastic membrane. To stretch the joint, air is pumped into the limbs. The plastic membrane then unfolds like an accordion, and the individual limbs align themselves almost horizontally. In order that the joint can also be bent, a hose is inserted into the limbs and filled with air as well. The air pressure in the hose causes the joint membrane to contract and the limbs to bend.

Based on this concept, the researchers are now constructing a multi-axis articulated robot that can support humans in various work steps. The use of air and movable plastic membranes makes the robot particularly pliable so that humans can work with it without risk of injury.

The Federal Ministry of Education and Research is supporting the research project with about 550,000 euros within the framework of the FHprofUnt funding line as part of the Research at Universities of Applied Sciences programme.