A short electric pulse is all it takes to generate and release a powerful vacuum in the blink of an eye. The novel vacuum gripper developed by the research team led by Professor Stefan Seelecke at Saarland University enables robot arms to pick up objects and move them around freely in space. The system works without the need for compressed air to generate the vacuum, it is energy efficient, quiet and suitable for use in clean rooms. The specialists for intelligent materials systems make use of artificial muscles, which are bundles of ultrafine shape memory wires that are able to tense and relax just as real muscle fibres do.
The wires also function as sensors and can sense, for example, when the gripper needs to readjust or tighten its grip.
Susanne-Marie Kirsch and her research colleague Felix Welsch (r.) are research assistants within the group led by Stefan Seelecke and are developing and optimizing the vacuum gripper technology.
Credit: Oliver Dietze
From April 23th to April 27th, the engineering team from Saarbrücken will be at Hannover Messe exhibiting the capabilities of their vacuum grippers at the Saarland Research and Innovation Stand (Hall 2, Stand B46). The team is looking for industrial partners with whom they can develop their system for specific practical applications.
Vacuum grippers are common tools in industrial production lines, where they are used to sort, convey and hold smooth and relatively flat objects so that screws can be driven in, surfaces painted or components assembled. Using vacuum grippers is typically a fairly noisy affair. The most common systems use compressed air, which not only makes them loud, but also means they need heavy ancillary equipment, which drives up costs and makes the entire system somewhat inflexible. They also consume significant amounts of energy.
The situation is quite different in the case of the new vacuum technology that has been developed by Professor Stefan Seelecke of Saarland University and the Center for Mechatronics and Automation Technology in Saarbrücken (ZeMA). The shape-memory vacuum gripper can produce a powerful vacuum using nothing more than a robot arm to guide it into position.
It does not require any additional electric or pneumatic drive system, it is light, adaptable, cost-effective to produce, and it runs noiselessly. It only needs electric current – more precisely, it needs small pulses of electric current: one to generate the vacuum and one to release it. No additional electric power needs to be supplied while the gripper is holding an object, even if the object has to be gripped for a long time or if it has to be held at an angle.
The technology is based on the shape memory properties of nickel-titanium alloy. ‘The term “shape memory” refers to the fact that the material is able to “remember” its shape and to return to that original shape after it has been deformed. If electric current flows through a wire made from this alloy, the wire becomes warmer and its lattice structure transforms in such a way that the wire shortens in length.
If the current ceases, the wire cools down and lengthens again,’ says Stefan Seelecke, explaining the key underlying material phase transitions. The ultrafine wires therefore contract and relax like muscle fibres, depending on whether an electric current is flowing or not. ‘These shape memory wires have the highest energy density of all known drive mechanisms, which enables them to perform powerful movements in restricted spaces,’ explains Seelecke.
To construct a vacuum gripper, the researchers arrange bundles of these fibres in the manner of a circular muscle around a thin metal disc that can flip up or down, like a frog clicker toy. Applying an electrical pulse makes the wires in the ‘muscle’ contract and the disc flips position. The disc is attached to a rubber membrane and if the membrane has been placed onto a flat smooth surface, when the disc flips position it pulls on the membrane, creating a strong and stable vacuum.
By bundling the wires together, the resulting motion is both powerful and very rapid. ‘Multiple ultrathin wires provide a large surface area through which they can transfer heat, which means they can cool down very swiftly. As a result, the bundle of fibres can shorten and lengthen rapidly, making it possible for the gripper to grab or release an object very quickly,’ explains Susanne-Marie Kirsch.
Kirsch and her research colleague Felix Welsch are research assistants within the group and are developing and optimizing the vacuum gripper technology as part of their doctoral research studies. ‘Currently, the gripper is able to securely hold objects weighing several kilograms. The gripper’s lifting capacity is scalable, with correspondingly more wires being used in large grippers,’ explains Felix Welsch.
And because the material from which the wires are made has sensory properties, the vacuum gripper is itself aware if the object is not being held securely. ‘The wires provide all the necessary information. The electrical resistance data correlates precisely with the extent of deformation of the wires. By interpreting the measurement data, the controller unit therefore knows the exact position of the wires at any one time,’ says Professor Seelecke. The gripper thus has an autonomous means of determining whether or not its vacuum is stable enough for the current task. It can also issue warnings in the event of a malfunction or material fatigue.
Press photographs are available at www.uni-saarland.de/pressefotos and can be used free of charge. http://www.uni-saarland.de/pressefotos. Please read and comply with the conditions of use.
German Version of the Press Release: https://www.uni-saarland.de/nc/aktuelles/artikel/nr/18794.html
Contact for press enquiries:
Prof. Dr. Stefan Seelecke, Department of Intelligent Material Systems at Saarland University: Tel. +49 681 302-71341, Email:
Susanne-Marie Kirsch: Tel.: +49 681 302-71362; Email: firstname.lastname@example.org
Felix Welsch: Tel.: +49 681 302-71362; Email: email@example.com
Paul Motzki: Tel.: +49 681 85787-545; Email: firstname.lastname@example.org
The Saarland Research and Innovation Stand is organized by Saarland University's Contact Centre for Technology Transfer (KWT). KWT is the central point of contact for companies interested in exploring opportunities for cooperation and collaboration with researchers at Saarland University. http://www.uni-saarland.de/kwt
Professor Stefan Seelecke and his research team at the Department of Intelligent Material Systems at Saarland University and ZeMA (Center for Mechatronics and Automation Technology) in Saarbrücken exploit the properties of the shape memory alloy nickel-titanium in a wide range of technical applications, ranging from a novel cooling system to components that can perform lifting and lowering operations precisely and noiselessly.
ZeMA – Center for Mechatronics and Automation Technology in Saarbrücken is a research hub for collaborative projects involving researchers from Saarland University, Saarland University of Applied Sciences (htw saar) and industrial partners. ZeMA is home to a large number of industry-specific development projects that aim to transform research findings into practical industrial applications.
Claudia Ehrlich | Universität des Saarlandes
New materials: Growing polymer pelts
19.11.2018 | Karlsruher Institut für Technologie (KIT)
Why geckos can stick to walls
19.11.2018 | Jacobs University Bremen gGmbH
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
19.11.2018 | Event News
09.11.2018 | Event News
06.11.2018 | Event News
19.11.2018 | Materials Sciences
19.11.2018 | Information Technology
19.11.2018 | Life Sciences