Appealing though general-purpose humanoid robots like C-3PO may be to many of us, real-life robots are usually most effective when they're designed for one specific purpose. In some situations, however, that purpose might not be known until the robot is in the field - at a disaster site, for instance, an autonomous robot might discover that it needs to squirm through debris, even though it wasn't designed to do so. One attempted solution to this problem has involved creating modular robots, that can take themselves apart and then reconfigure themselves as needed. Scientists from the University of Pennsylvania's Modular Robotics Laboratory, however, are taking a slightly different approach. They've created a robot that can build other purpose-specific robots, using electromechanical modules and self-hardening foam.

First of all, what's wrong with using just the interlocking modules and no foam? Well, if the modules are only used where they're really needed (such as in areas that bend or perform sensory functions), and the rest of the robot is made out of foam, the resulting machine will be much lighter and less expensive than would be the case otherwise.

The base of the robot-building robot (aka FoamBot) is a small motorized cart, originally designed for the Mini-PR2 robot. On this cart are a container of off-the-shelf insulation foam, a spring clamp-operated valve, a foam-dispensing nozzle, and an actuator that raises and lowers the nozzle. A laser pointer mounted on the nozzle allows the robot's human operator to aim the foam spray - FoamBot is not autonomous ... yet.

The modules are referred to as "clusters," as each one consists of a row of three joined sub-modules, which incorporate actuators and microcontrollers. Attached to either end of each cluster are foam-core faceplates, which have 5-centimeter (2-inch) bolts sticking out of them that will be embedded in the foam. The FoamBot starts by laying the clusters out on the floor, in the configuration that they will take within the finished robot. It then links them by spraying foam between them, and in some cases also uses the foam to add appendages.

So far, the ModLab scientists have used FoamBot to create an undulating snake-like robot ...

... and a sort of lizard-like quadruped robot.

They have also demonstrated that FoamBot itself could use its foam-spraying abilities to encase and pick up hazardous substances, and to build doorstops in emergency situations.

Source: New Scientist