When the arms of a robot move to pick up an egg or an electric lamp, the greatest precision possible is essential. To this end, advances in the science and technology of materials have provided the design and control of systems equipped with sensors and actuators built with new materials.
The Automation Group at the Department of Electricity and Electronics of the Faculty of Science and Technology at the Leioa campus of the University of the Basque Country (UPV-EHU) is studying the stimulus-response characteristics of various kinds of materials to be used in the generation and measurement of precise movements in electromechanical systems in miniature and in robotics.
The studies focused on two types of materials in concrete, and which had promising characteristics for micropositionng applications: shape-memory alloys (SMA) and magnetic shape memory (MSM) alloys or ferromagnetic shape memory alloys (FSMA). All these smart alloys are new materials, catalogued as intelligent for their ability to memorise shape and other novel properties.
Shape-memory alloys are capable of remembering their original size and shape despite having undergone a deformation process. The most common alloy amongst these is that generically known as nitinol, given that it is made of almost 50% nickel and almost 50% titanium. It is on the market and is sold in the form of wire.
Magnetic shape memory alloys are ferromagnetic materials capable of withstanding large transformations that are reversible both in shape and size when a magnetic field is applied to them. They do not exist as yet commercially and are currently only made in research laboratories.
The team built a number of potentially useful devices for robotics, using these shape memory materials, and investigated new applications fundamentally aimed at light or miniaturised electromechanical systems.
The use of SMA as actuators in low-precision applications is not something particularly novel. However, the researchers at the UPV/EHU have developed some experimental devices that radically improve the control of positioning of these actuators. Thanks to this, they have built a prototype of a lightweight gripping claw device for a flexible robot of small dimensions, capable of handling small objects. To achieve this, they placed nitinol wire between two elastic metal sheets in such a way that, when an electric current is applied to the wire, the sheets contract and the “claw” completely closes, gripping small objects around it. With the current switched off, the claws open completely. Nevertheless, the UPV/EHU team has managed to enhance the opening-closing movement, to the point of precision of within a micron. This level of precision is sufficient for many applications, for example in machine tooling.
As regards magnetic and ferromagnetic shape memory alloys, the UPV/EHU researchers designed a device which had a precision of positioning objects to within 20 nanometres. Being a handmade device with a simple control, the researchers do not doubt that it can be improved. Moreover, it could be a serious candidate to substitute current high precision devices, given that positioning devices manufactured with ferromagnetic shape memory alloys have the great advantage that, once suitably positioned, they do not consume energy. The use of FSMA actuators could become highly important in certain applications, for example, in large-dimension telescopes that have a great number of mirrors that have to move with great precision in order to focus correctly.
All these devices, currently at a laboratory stage, are useful for testing the basic characteristics of the materials, but perhaps in the future they could be end-product commercial prototypes for robotic devices and in micro and nanopositioning.
Alaitz Ochoa de Eribe | alfa
World's smallest optical implantable biodevice
26.04.2018 | Nara Institute of Science and Technology
Cell membrane inspires new ultrathin electronic film
26.04.2018 | University of Tokyo
Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is...
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
26.04.2018 | Power and Electrical Engineering
26.04.2018 | Life Sciences
26.04.2018 | Power and Electrical Engineering