Bio-inspired modules open new horizons for robotics

Inspired by cell biology, European researchers have created the world’s first shape-shifting robot made of many modules, which could lead to new applications in fields ranging from medicine and space exploration to education and entertainment.

On display at IST 2004 in The Hague and being showcased on 17 November in Tokyo, the HYDRA project’s robots have broken new ground in robotics and artificial intelligence through a simple but highly effective design that allows the devices to configure themselves into almost any shape and perform a variety of functions. “We have shown that electronic artefacts can change not only their behaviour but also their shape during their lifetime, something that I don’t think most people believed was possible,” explains Henrik Hautop Lund, a professor at the Maersk Institute in Denmark and the coordinator of the HYDRA project, which was funded under the European Commission’s IST Programme.

Over the last three years the Maersk Institute, together with LEGO, the University of Edinburgh and the University of Zurich, developed two types of spherical modules, the ATRON and the HYDRON that can operate autonomously, communicate with each other and be programmed to take on virtually any shape and behaviour. The HYDRON was developed for use in fluids while the ATRON, which is the module being presented widely this week, was created for terrestrial use. “We based the design on the way biological cells interact, how they move, die and reconstruct themselves, and we emulated that in the modules, which are essentially building blocks for robotic devices that look very much like a string of atoms or cells when connected together,” Lund says. “These are the first robots of their kind, especially in terms of the simplicity of their design and their ability to change shape.”

Each ATRON module is an 11cm-diameter sphere constructed from two hemispheres – a north and south – that can rotate around the equator. Each hemisphere has a set of male and female connectors that allow it to hook together and operate in unison with other modules – as few as one or two or as many as several hundred. “The more modules we have, the more interesting the shapes we can produce and the functions we can perform,” Lund says, noting that the project partners have so far manufactured one hundred ATRON units. “For example, the design could start off as a small car with four modules touching the ground and acting as wheels and other modules connecting them. The car might come to a hole in a wall it can’t fit through so the modules would communicate with each other and transform into a snake. After it goes through the hole the robotic snake finds itself faced with a staircase. Now, because the snake can’t go up the staircase it transforms itself into a climbing device, goes up the stairs and reverts back to being a car.”

Each of the modules are equipped with infrared sensors to detect other modules and objects, and infrared transmitters and receivers to communicate with each other and receive orders. An onboard computer system consisting of four small processors is the artificial intelligence core of the modules allowing the robots to operate autonomously, while additional sensors measure movement, speed of rotation and degrees of tilt. The male and female connectors, as well as the rotation, are operated by small but powerful motors that allow one module to move and hold two others, while the hook design allows the modules to connect quickly even if they are misaligned. Perhaps one of the most innovative solutions developed by the project refers to how the modules obtain power.

“Because each module is fitted with a small battery, similar to the most advanced batteries used in mobile phones, the problem we faced is what to do when the battery of one module runs out, given that in a complex formation the death of one module would make the rest useless,” Lund explains. “We overcame this problem by constructing the modules with electrically grounded skeletons through which they can transfer power allowing them to regenerate much like biological cells.”

In fact, according to Lund, biological cells could one day end up meeting these robotic brethren. “This may be a far off vision, but if we could bring these kinds of robots down to the nano level there are possible uses for them in medicine, where they could be used to repair the body internally,” the coordinator says. “We can also envision them being used to inspect hazardous environments or in space exploration where they could replace devices such as the Mars rovers because they would be more effective at overcoming obstacles.”

In the shorter term, Lund sees potential for the ATRON to be used in education and entertainment – “a new concept in toys, more advanced than say the AIBO dog or the WonderBorg robotic insect” – something that has elicited great interest in Japan. “Fundamentally, however, this is a research project through which we have proven that shape-shifting robots can be created,” Lund says. “Now it’s a question of letting people know about it and seeing what new horizons it opens up.”