- Tiny metal robots turn to liquid to escape cage
- Origami-inspired robots rapidly change shape
- Self-configuring robotic cubes could be used to create structures in space
- Swarm of self-transformable ShapeBots can visualise data in 3D
Experts predict that shape-shifting robots might well be the future of robotics. More and more researchers are venturing into developing robots that can adapt their shapes and behaviours on demand, enabling them to overcome obstacles and continue performance in spite of changing circumstances or environments. Some shape-shifting robots are created with rigid components and actuators to enable them to change from one shape into another, while others are made from innovative materials that allow them not only to change shape but take on a different consistency as well. And like with many other engineering designs, biology serves as inspiration for these robots, as biological organisms often consist of complex anatomical structures that can adapt to environmental changes. The authors of the report Shape Changing Robots: Bioinspiration, Simulation, and Physical Realisation write: “Evolution did not result in hard-coded body plans purely determined by genetic factors, but rather produced diverse examples of intelligent self-modifying systems which adapt to numerous extragenomic influences. In this way, biology serves as an important proof-of-principle, and design challenge, for artificial intelligence and shape changing robots”. In this article, we will introduce four innovative shape-shifting robots that have recently been developed and are poised to transform robotics in the years to come.
Tiny metal robots turn to liquid to escape cage
These tiny, shape-shifting robots, designed by engineers at the Chinese University of Hong Kong, have been all over the news in recent weeks. And this is no surprise, as the robots can rapidly shift between solid and liquid states and perform incredible feats, the most astounding one of which is ‘oozing’ out from between the bars of a cage — which is reminiscent of the T-1000 assassin robot in the Terminator franchise — but also climbing and jumping. In fact, the T-1000 was the inspiration for the robots. The tiny shape-shifting machines, which are also magnetic and can conduct electricity, could be used to perform many different tasks in various fields. In the future, they could be used to repair electronics by oozing into circuits, acting as conductors as well as solders. In biomedicine, they could be put to work to extract foreign objects from the body, or deliver targeted treatment to certain organs.
Chengfeng Pan, an engineer at the Chinese University of Hong Kong who led the study, says: “Giving robots the ability to switch between liquid and solid states endows them with more functionality”. Pan continues: “We’re pushing this material system in more practical ways to solve some very specific medical and engineering problems”. The shape-shifting material used for the robots is called ‘magnetoactive solid-liquid phase transitional matter’. It is made from the metal gallium, which has a melting point of only 29.8 °C, and is embedded with magnetic microparticles. Mechanical engineer Carmel Majidi, who heads the Soft Machines Lab at Carnegie Mellon University and is a senior author on the new study, explains: “The particles make the material responsive to an alternating magnetic field, so you can, through induction, heat up the material and cause the phase change. But the magnetic particles also give the robots mobility and the ability to move in response to the magnetic field”. The material was tested in various contexts in which magnetic fields were used to enable the robots to climb over obstacles and even split in two in order to work together to move objects.
Origami-inspired robots rapidly change shape
Researchers at Virginia Tech recently published the paper Shape Morphing Mechanical Metamaterials Through Reversible Plasticity. The paper features in Science Robotics and showcases a shape-morphing composite material that uses a phase-change metal skeleton to enable a flat sheet to transform into complex, load-bearing shapes. The material is made from an elastomer with an origami-like pattern of cuts in it, which determines the shape the elastomer will change into. The integrated heating element liquefies the metal alloy skeleton inside the sheet, which causes the material to shapeshift. This phase change allows the shapeshifting to be reversible and enables self-healing as well. Integrated with motors, onboard control, and embedded heaters, this material could, among other things, be used to create morphing drones that can autonomously shapeshift from a ground to an air vehicle. While this process takes a while, it can also be sped up to a fraction of a second by using force, such as pressurised air. This causes the elastomer and the metal skeleton to stretch and ‘pop into shapes’ that can be maintained without consuming power. Reconfiguration can be repeated over multiple cycles, meaning that morphing into different, load-bearing shapes can be performed again and again, enabling the development of highly mobile and adaptable machines.
Self-configuring robotic cubes could be used to create structures in space
Another recent shape-shifting robotics development comes from the University of Calgary and MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL), where scientists have created a cubical, shape-shifting robot system called the ElectroVoxel. These self-configuring robotic cubes have no motors or moving parts and group together semi-autonomously to create larger objects. The edges of these 60-millimetre cubes consist of an electromagnetic ferrite core covered with copper wire. These edges, which either repel or attract each other depending on the polarity of a magnet, enable the ElectroVoxels to move around each other and shift into different orientations. The configurations and movements of up to 1,000 of these cubes can be programmed using software that connects to the ElectroVoxels via a wireless communication system. For instance, you can control the speed at which the cubes move, ensure that they don’t bump into each other, and instruct them to take on a specific shape.
On the NASA aircraft nicknamed the ‘vomit comet’ — a type of fixed-wing aircraft that provides near-weightless environments for research and training purposes, as well as gravity-free movie shots — the scientists discovered that the ElectroVoxels can operate in low-gravity conditions. This makes these tiny robots very suitable for building and altering structures in space and assisting with spacecraft inspections. Other use cases envisioned by the scientists include the creation of self-sorting containers. Martin Nisser, a PhD student at CSAIL and lead author of a paper on ElectroVoxels, explains: “While the potential benefits in space are particularly great, the paradox is that the favourable dynamics provided by microgravity mean some of those problems are actually also easier to solve — in space, even tiny forces can make big things move. By applying this technology to solve real near-term problems in space, we can hopefully incubate the technology for future use on Earth too”.
Swarm of self-transformable ShapeBots can visualise data in 3D
A group of PhD students, in collaboration with researchers from the University of Colorado Boulder and the University of Tokyo, have recently developed a swarm of small, self-transformable robots named ShapeBots. The bots were developed in a bid to create new “computational mediums that can augment and transform how humans think, design, program, and interact with their surrounding environment”. Each bot measures 3 x 3 cm and is fitted with wheels, a motor, and a battery. An individual bot can be stretched up to 20 cm, both horizontally and vertically, and can also bend and change volumetrically. The ShapeBots can alter their collective as well as their individual configuration, to display information in various ways, or as explained by the students: “physicalise data” in 3D environments in order to enable users to physically interact with the information they see. The students envision a future in which our environments might include small, shape-shifting robots that can help us make our lives easier or more interesting. For instance, the swarm bots could display information about geographic locations, act as interactive graphics, facilitate ambient assistance for everyday life, provide a physical preview of a CAD design, ‘wipe’ rubbish from a messy desk, and so on.
Each ShapeBot is made of common materials and simple electronics. A small motor enables the bots to move around, while other motors allow them to retract and extend their ‘arms’. A computer with camera vision tracks the position and controls the movements of the bots. The ShapeBots can be ‘choreographed’ individually as well as in a team, and could find various useful applications for dynamic physical media, such as in museums, schools, and other educational settings. Ellen Do and Mark D. Gross, two of the researchers, explain: “Our study shows that we can use a swarm of small cheap robots to interact with information, bridging the physical and digital worlds. However, the ShapeBots we developed are still a prototype. They are relatively robust in a lab environment, but they wouldn’t last long in a third grade classroom”. In the years ahead, the researchers would like to reduce the size of the robots, which would enable much higher-resolution visualisations, increase reliability, and reduce production costs.
In closing
Incredible advances have been made in robotics in recent years. Robots are becoming more and more versatile, sophisticated, and adaptable, with the concept of shape-shifting robots being one of the latest developments in robotics. The majority of the robots described in this article are still in their prototype phases and have been created to discover potential future applications in an ever-expanding variety of conditions. With continued research and development, these shape-shifters are expected to become even more advanced and capable in the years ahead, undoubtedly leading to many fascinating new possibilities in various industries.
