Tortoises walk on land by alternately moving its legs and carry their shells above the ground. When filled with compressed air, the BionicTurtleWalker simultaneously pushes its diagonally positioned legs downwards and pushes itself forwards, just like its model in nature. The centrepiece of the BionicTurtleWalker is a pneumatic logic module developed by the Plant Biomechanics Group of the Botanic Garden Freiburg and the "Living, Adaptive and Energy-autonomous Materials Systems (livMatS)" Cluster of Excellence at the University of Freiburg.
Pneumatic logic module
This "control centre" of the turtle performs the tasks that are otherwise carried out by valves and electric controllers in pneumatic systems. This allows it to precisely switch the movements of the four legs and only one tubing connection is required for the compressed air supply.
The pneumatic logic modules have several advantages over conventional systems. They consist of two valve chambers with which Boolean operations can be carried out.
Thanks to their design, they can be additively manufactured from flexible material and operated with low pneumatic pressure. This greatly reduces production costs, system complexity and operating costs.
"The pneumatic logic controller opens up new areas of application for completely flexible soft robots where classic, electrically controlled systems would fail."
Dr Falk Tauber, livMatS Cluster of Excellence at the University of Freiburg
Flexible yet robust material
Everything,from the armour to the pneumatic logic module to the legs of the BionicTurtleWalker, is 3D printed and made of thermoplastic polyurethane (TPU). This material combines the properties of rubber and polymer, making it durable, flexible and yet robust. As a result, the logic module can withstand up to 900 kg of surface loads.
This allows it to deform and then return to its original state. What’s more, the TPU can be melted down and reused, in keeping with the concept of the circular economy.
Outlook and potential
The technology of pneumatic logic modules made from TPU is also suitable, for example, for applications where people and robots work together. By combining several modules, it was possible to produce pneumatic control elements for pneumatic soft robots that can have any number of degrees of freedom.
This results in numerous application areas. One module alone can control the opening and closing of a pneumatic gripper, for example. For more complex applications, modules can be combined and produced as a single block or integrated directly into soft robots.
"When we combine air with flexible materials, we still have many opportunities for innovation. This combination has the potential to make robots even more life-like."
Sebastian Schrof, designer in the Festo bionics team
Part of the Incredible Machine
The BionicTurtleWalker is part of the Incredible Machine,the anniversary exhibit celebrating 100 years of Festo. It works on the principle of a Rube Goldberg machine, in which one movement triggers the next. The Incredible Machine demonstrates the history of automation technology from the past to the present and reflects our wide range of competencies and our comprehensive expertise.
