“The way cartoon character Barbapapa and his family members take on any shape they want has captured the imagination for generations. Making this a reality offers unprecedented possibilities. All the more understandable is the enthusiasm of the researchers at Eindhoven University of Technology who have joined forces in soft robotics. This is a new field with countless potential innovations: from an artificial heart to ultra-small robots that perform internal surgery, dispense medicines or repair complex machines. Plant-based food sensations, self-cleaning coatings or artificial ‘remote hands’ are also on the horizon.
“Scientifically, it’s an incubator for new directions and research”, said Bas Overvelde, associate professor within the Soft Robotics Group (part of the Mechanical Engineering faculty) and scientific group leader of the Soft Robotic Matter Group at AMOLF. “It’s a great topic that brings researchers together, which continually generates new ideas.” In 2020, Overvelde received a five-year ERC start-up grant of more than 1.5 million euros to increase the application perspective of soft robots.
To this end, he is collaborating with colleagues from different disciplines and faculties at TU/e, such as Chemical Engineering and Chemistry, Industrial Design and Mechanical Engineering and ICMS. “Such an interdisciplinary approach is characteristic of a new science with which we are pioneering in all kinds of areas: materials, mechanical intelligence, interaction with humans, design. Precisely because it requires a very different way of thinking that goes more towards the intelligence of nature. It’s a form of artificial intelligence.”
Chain of research disciplines
An essential feature of soft robotics compared to hard robotics is its autonomous adaptability, but that also makes it less predictable and requires new design methods to get soft robots to perform the desired tasks or functionalities. ‘Traditional’ robots have hinge points and other hard moving parts, making them well suited for programmable, repetitive actions, explains researcher Jaap den Toonder - leader of research section Microsystems.
“Soft robots respond to stimuli such as air pressure or light. Their movements result from the reaction and deformation of the material, which is where the intelligence lies. That leaves a lot of room for complex possibilities. That’s why a whole chain of research disciplines is needed: to devise and develop the right materials (chemistry), to make the mechanical design and to direct and control the systems (mechanical engineering).” In the new Interactive Polymeric Materials Research Center the development of interactive polymers is one of the main goals and these polymers are the basis for taking soft robotics further. Within the NWO Gravitation project we will therefore also develop prototypes.”
Moreover, because of their flexibility and softness, soft robots are ideally suited for human interaction, which researcher Miguel Bruns of the Faculty of Industrial Design is working on. “Soft materials fit humans better than hard, mechanical ones. But what makes it especially innovative are the dynamic properties that the use of new materials entails. This makes it possible to manipulate physical properties in a controlled way and adapt them to the needs of the user, such as humans. Although animals, plants or buildings can also be users for that matter. That adaptive nature is the interesting thing about soft robotics.”
Or, as Overvelde puts it, “A soft robot will never squeeze your hand. The power of hard robotics makes collaboration between humans and robots more difficult, so soft robotics is a way to make that interaction safer. In the slipstream, that also helps social acceptance, because soft robots are closer to us.”
Which in turn contributes to one of the applications he’s focusing on: the development of an artificial heart. “What is more likely to be accepted in our bodies; a hard pump or a beating object that resembles a natural heart? Such questions must ultimately be tested and answered in a human environment.”
Feeling without being present
That’s where researcher Irene Kuling of research section Dynamics and Control comes in. “My background is in haptics: anything to do with perception through hands. In that respect, we are currently using soft robotics in two ways: the development of a hand that imitates human movements as lifelike as possible, and the development of objects with which we can provide haptic feedback to people from a distance. In other words: feeling without being present. Think, for example, of maintenance in a nuclear power plant, giving a hand via video calling, or digitally touching curtains before ordering them online.”
In this way, soft robotics really adds value to current sensory capabilities, Kuling emphasizes. “A lot has already happened in that area, such as 3D images, sharper pixels or surround sound, but in terms of sensing, very little exists. Soft robotics is changing that and we are just at the beginning. With traditional robotics we think very much in performance terms, whereas with soft robotics we can be much more creative. Who knows, it might lead to a real life Barbapapa, something that can turn into both light and heavy objects.”
Encouragement from NASA
That unlimited mindset also characterizes researcher Danqing Liu from the Faculty of Chemical Engineering and Chemistry. “Since soft robotics lacks the power of hard robotics, we need to turn the differences into an advantage. Such as the combination of moving surfaces with dynamic coatings, which allows us to use vibration to clean hard-to-reach objects without water. For example, solar panels, or think of the Mars Rover, which has to deal with sandstorms. NASA has already encouraged us several times to work out this principle further to meet the extreme conditions in space.”
Liu emphasizes that ‘soft robotic coating’ is very easy to integrate into existing devices. “It creates so many possibilities. Also in the field of haptics, with coatings on screens that allow you to feel what is happening in another place. That’s valuable for blind people, or for surgeons to experience what’s happening in the body. Another application is a control panel in cars that allows you to regulate functions without looking, so that you continue to pay attention on the road. Soon we’ll actually be able to do two things at once.”
She dares to think even bigger: “If we apply this form of touch sensation feedback on a large scale, it will have a huge impact on the human machine interface. We’re going to change the world.”
Taking intelligence further
Sounds promising, but plenty of follow-up research is needed for that. “We are pioneering now,” says Den Toonder. “The main question is how do we bring intelligence to the point where soft robots react autonomously, for example to their environment or to chemical substances. Ultimately, we want to make robots on a microscopic scale, smaller than a hair’s breadth, that walk through the body and deliver drugs locally or do surgery. Or that perform repairs in complex machines with very small parts.”
According to Bruns, ‘we can make it as broad as we want’. “Edible robots that change shape to deliver drugs or nutrients locally, or create new sensations to bring plant-based foods closer to the experience of meat. One example is 3D printing algae-based hydrogels in the shape of bacon, which react similarly to the animal product during baking.”
For Overvelde, there is a lot of potential in these other ways of thinking. “This new technology requires new solutions, so we want to involve as many other research fields as possible.”
That’s why philosophers will also be needed in the long run, Kuling adds. “Working with soft systems creates a very different view of the concept of robotics. Does that definition mainly fit the programmable hard form we already know, or also the soft variant that is less controllable? So what makes a robot than? Now it is an umbrella term that will gradually branch out.”“