A team of researchers at the University of Minnesota Twin Cities have been working on a way to move objects without any contact! They developed a way to manipulate objects using ultrasound waves. Contactless movement and manipulation could become very important in industrial applications, including manufacturing and robotics. Their study and its findings were recently published in Nature Communications.
Physics tells us that waves (mechanical, sound, and light) can manipulate the material they are traversing through, and thus may manipulate objects, in theory. This has been demonstrated in the past for objects that are smaller than the wavelength of the given wave, which was on the order of millimeters for sound waves and nanometers for light waves.
The team of researchers at the University of Minnesota Twin Cities has developed a method that can move much larger objects. According to Ognjec Ilic, co-author of the study and Benjamin Mayhugh Assistant Professor in the University of Minnesota Department of Mechanical Engineering, “We have known for a while that waves and light and sound can manipulate objects. What sets our research apart is that we can manipulate and trap much bigger objects if we make their surface a metamaterial surface or a ‘metasurface.’”
His team has developed a method that can move larger (than millimeter and nanometer) scale objects using the principles of metamaterial physics. A “metamaterial” is a material that is artificially engineered to interact with light or sound waves. The team placed metamaterial patterns on the surfaces of objects, and in doing so, they were able to steer these objects in certain directions without physically touching any of the objects.
The tiny patterns are put on the surface of an object, and then sound can be reflected off the surface of the object, applying an acoustical force to the object. Altering the direction of the incoming sound waves can alter the direction in which the object moves. In fact, the team was able to use this technique to not only move an object forward, but also to pull an object toward a source. Sounds like something straight out of science fiction!
Matthew Stein, first author on the paper and a graduate student at the university, notes that “[c]ontactless manipulation is a hot area of research in optics and electromagnetism, but this research proposes another method for contactless actuation that offers advantages that other methods may not have.” One of the advantages it that the object that needs to move would not need to carry a source of energy to perform a task.
This study is just the beginning, demonstrating how this concept works. In the future, the team wants to test out higher frequencies of sound waves, as well as different materials and other size objects. If successful, there are many applications in the fields manufacturing and robotics where this type of technology could become incredibly important.