Muscling Through the Virtual Mountain

Test subjects will run and jump in a new lab at the Cluster of Excellence CITEC

This year, the Interactive Locomotion Lab was founded at CITEC, joining some 40 special laboratories at the Cluster of Excellence. Here, researchers from both biology and computer science study the role of the body in movement control and planning. A special apparatus was custom-built for their experiments, made of a platform with a treadmill and a virtual environment. With the first introductory studies having been conducted earlier this year, the experiments will now be starting.

Prof. Dr. Volker Dürr (right) heads the Interactive Locomotion Lab. His colleague Florian Hofmann (left) is currently preparing for the main study.The Biological Cybernetics research group set up the new lab in the biology wing of the main university building. Here in the grey basement area, test subjects are greeted with a virtual oasis of green. The researchers placed six large screens and 14 cameras on a Stewart platform – a platform that can be shifted and tilted in all directions with its six motors.

The test subjects wear a special pair of glasses, which are captured by the platform’s cameras. They then walk or run on a treadmill that was installed on the Stewart Platform. The virtual path leads over a trail with green fields to the left and right. Every so often, study participants are confronted with an obstacle, which they have to either step over or jump over. “With these obstacles in the virtual trail, we wanted to find out how we humans react to our surroundings,” says Professor Dr. Volker Dürr, a biologist who heads Biological Cybernetics, a research group that is part of Bielefeld University’s Faculty of Biology and the Cluster of Excellence CITEC.

At the Interactive Locomotion Lab, test subjects run through a virtual landscape where they have to jump over obstacles. The 180-degree projection curves around the test subject, creating a three-dimensional effect. The treadmill can be tilted both upwards and downwards, thus allowing the test subjects not only to walk on a flat surface, but it also gives them the feeling of walking all the way up and down the mountains. At the beginning of the year, the safety inspection was carried out and since the preliminary test studies have been completed, the first experiments can now be started.

“We want to find out how humans plan and control dynamic running and jumping motion,” says Dürr. “For this, we purposely give the test subjects misleading feedback. As an example of this, the researchers use the device to pretend that a virtual hurdle was not cleared, even though the reality and the perception of the test subjects is contrary to this. How do the test subjects deal with this discrepancy? Do they adjust their effort for the next jump? How sensitive are they to changes? And how big can the conflict be between the feedback the test subjects get and their visual impression? “We have a sense of how much force we need, for instance, to jump over an obstacle or how we have to move our arm in order to throw a ball at a target,” says Dürr. “Yet we can’t always be certain. Sometimes we think that we’ll make it over an obstacle but then we knock into it. In our research, we’re interested in how this internal representation of the body works.”

Dipl.-Ing. Florian Hofmann setting up the virtual landscape. At this time, the researchers will be measuring motion on the treadmill, but in the future, muscle activity and spring could also be measured with, for instance, shoe treads. “Our findings from the studies here at the Interactive Locomotion Lab will also provide us insight that can be used in artificial systems,” says Dürr. “Based on human body representation, we will look at which motion sequences should be firmly set in robots and which would be better off being more dynamic and adaptable.” 

Contact:
Professor Dr. Volker Dürr, Bielefeld University
Cluster of Excellence CITEC
Telephone: 0521 106-5528
Email: volker.duerr@uni-bielefeld.de