The aim of this development so far: robots should act in such a way that they are moved towards a desired position like a mechanical spring. However, springs always return to their original position. DLR researchers have now presented a more advanced concept in the journal Science Robotics. Their approach allows robots to yield without moving back to their initial state like a spring; a behavior similar to humans when performing joint practical tasks – one human takes command, the other remains flexible and compliant.
Dr. Michael Panzirsch, scientist at the DLR Institute of Robotics and Mechatronics, explains: “The new elasto-plastic approach makes cooperation between humans and robots much easier, as the robot can now clearly distinguish whether its movement is the result of its own command or has been influenced by a moving environment. The robot should only react plastically to the influence of such an environment, i.e. avoid and stop in place.”
In addition, the innovative controller generally offers the possibility of simplifying interaction with objects that have a complex movement. For example, a door can only be opened by rotating it around an axis. The robot follows the correct direction of movement, i.e. the rotation around the axis by the controller, almost automatically and without the need for an additional model of the door. This is comparable to a person opening a door with their eyes closed, simply pulling on the door handle and automatically adapting to the circular path in a plastically compliant manner.
Application in space research and care
The DLR Institute of Robotics and Mechatronics has been researching sensitive robots for decades. It has developed the first robotic arm that stands out from classic, rigid industrial robots thanks to its remarkable flexibility. The elasto-plastic control approach was successfully tested in a space mission in January 2024. As part of the Surface Avatar project series, the teleoperation of several robot-based avatars on a planetary surface is being investigated. The focus here is on the successful cooperation of a heterogeneous team of robots, which should be able to carry out collaborative tasks. “For the first time, our controller enabled cooperation between a rover from the Human Robot Interaction Laboratory of the European Space Agency ESA and a humanoid DLR robot controlled by an astronaut on the International Space Station ISS,” explains Dr. Neal Y. Lii, Scientific Director of the Surface Avatar program.
However, the versatility of the technology is not only evident in space. In the care sector, the elasto-plastic controller is proving to be a valuable aid. In the SMiLE project series (service robotics for people in life situations with limitations), DLR researchers such as Jörn Vogel are developing concepts for assistance systems designed to provide people with physical limitations and people in need of care with effective support in everyday life. The elasto-plastic controller not only facilitates cooperation between humans and robots, but also enables the robot to automatically slip into a subordinate role without the need for additional, complex sensor technology.
Advances in robotics, particularly in terms of compliance and adaptability, are not only accelerating the integration of robots into everyday life, but also increasing their safety and effectiveness. In a future where humans and machines work ever more closely together, it will be crucial that these machines not only react, but also understand – and do so in a way that meets human needs and idiosyncrasies and models itself on human capabilities.
– – – – – –
Further links
👉 www.dlr.de
Photo: DLR (CC BY-NC-ND 3.0)
