This image shows how two microbots can be independently controlled when operating within a group. (Purdue University/David Cappelleri)

Researchers are using a technology likened to "mini force fields" to independently control individual microrobots operating within groups, an advance aimed at using the tiny machines in areas including manufacturing and medicine. Until now it was only possible to control groups of microbots to move generally in unison.

The team developed a system for controlling the robots with individual magnetic fields from an array of tiny planar coils. The microbots are magnetic disks that slide across a surface. The robots are moved using attractive or repulsive forces, and by varying the strength of the electrical current in the coils.

Independently controlled microbots working in groups might be useful in building MEMS machines that could have numerous applications from medicine to homeland security.