Swiss robot grabs without touching
Today, the industry uses robots to walk and move all sorts of different items around production. Tiny components in watches or microchips, are still handled manually with tweezers because they are too small and fragile for the robots' rough hands.
Robots take over construction
A driverless excavator excavates, and a robotic arm lays 1,000 bricks per hour. With new super-precise sensors and artificially intelligent algorithms, robots have already built entire houses, and in a few years, they will be the new electronic construction chess. The noise from excavators, cement mixers, and tools buzzes from a construction site. A roof will be mounted on a house while excavation for a foundation is underway on the neighboring ground. In a third house, the plasterboard is put up. There is not a single person at the construction site. All the craft tasks - from casting foundations to placing the last tile - are done by robots while drones check the progress.
“Conventional robotic grabbers tend to damage fragile objects. To counteract, soft rubber-like grippers can be used. Although they do not damage the subject, they are easily contaminated, as is often the case with limited accuracy,” says Marcel Schuck, a postdoc at the ETH Technical University in Zurich.
He and his colleagues are trying to solve that challenge with the help of sound. They have now presented a contactless robotic gripper that can move items completely without touch.
The technique is not new and is known as acoustic levitation. The principle works by getting opposite rays from sound waves to create standing waves. The standing waves have peaks that oscillate between high and low pressure, and thus they can be used to lift and push an object against gravity.
In fact, ultrasound has been studied for that function for more than 80 years, including in aerospace. High-frequency sound waves create a pressure that we humans can neither see nor hear. The small objects are, so to speak, trapped between the two apexes of a sound wave, which arises by changing the sound level around the subject extremely quickly.
In the past, scientists have caused water drops and table tennis balls to soar.
“Grabbing small and fragile items is a significant challenge, for example, in the production of watches, the semiconductor industry, and micromechanics. Therefore, it is very limited what is available from automation and robotic solutions for precisely those tasks, because there is no suitable gripper technology, “says Marcel Schuck.
This is what another prototype of the acoustic robot gripper looks like
Uses ordinary robotic arm
It is not enough to be able to grasp a subject, it must also be able to be manipulated in the right direction. Marcel has solved that challenge relatively simply by placing his acoustic gripper on a conventional robotic arm, which then moves the subject from A to B, while the subject hovers in the smaller acoustic gripper.
“A big advantage of our technology is that we can grab not only an object but also manipulate it. We do this with relatively inexpensive equipment, for example, with a robotic arm that performs the positioning of the workpiece, ‘says Marcel Schuck.
However, it is unclear how the small item is initially placed in the contactless gripper. In the video, Marcel Shuck even places the subject with tweezers. So completely done with the prototype, they are not at ETH.
In Germany, the Beckhoff Automation automation company is trying a slightly different version of a floating conveyor belt, namely magnetic levitation.
The modules – or ‘mover’, as Beckhoff calls them – contain a permanent magnet, which is pushed upwards by electromagnets in the ’tiles’ that make up the transport system called Xplanar. The mover itself is thus completely passive and must not be charged or supplied with energy.
The system makes it possible to move the movers individually in all directions at speeds of up to 4 m / s. The largest mover can carry up to 6 kg. Products, and it is actually possible to connect multiple movers. The lifting height itself can be up to 5 mm, which means that it is also possible to tilt the mover with a slope of up to 5 degrees. Here, however, it is not the subject itself that hovers, but only the plate on which the subject is placed. This means that the small movers are not in contact with the substrate.
By using a ‘floating’ conveyor belt, the expectation is to reduce the risk of contamination in, for example, clean rooms or other places where you would like to avoid contact and contact.