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Big Steps in Small Robots

Over the years, robots have had a tremendous impact in manufacturing. But after two decades of research in micromachines, extremely small robotic systems still lack the ability to sense, think and act independently or function reliably. Also missing are methods to manufacture them in large numbers and beyond two dimensions, which is required for many micro and nano manipulation tasks. However, understanding and mastering manipulation and assembly with small robots is essential for many future innovations in micro and nano technology.

Electrical Engineering Assistant Professor Dan Popa, who conducts much of his research in the Automation & Robotics Research Institute’s Texas MicrofactoryTM, is changing that. Dr. Popa investigates fundamental design aspects of new types of automated machines that operate at small scales. Recently, he formulated the first precision-adjusted design rules and metrics for multi-scale robotic systems, and harnessed them to overcome limitations of standard microassembly. This resulting assembly technology is much faster and more reliable than manipulation by an operator looking through the microscope.

While a typical automobile assembly plant contains hundreds of robots, the most advanced micro/nano manipulation system in the world today contains fewer than 10 precision robots. Conventional manipulation can assemble complex micro and nanosystems, but they are neither fast nor scalable to large numbers of objects. Methods such as fluidic self-assembly, though efficient in the number of objects they can manipulate, suffer from complexity and yield limitations to construct useful micromachines.

At the micro scale, Dr. Popa developed three-dimensional precision assembly systems with guaranteed high yields (over 99%). These systems are composed of a small number of conventional precision robots with modular and reconfigurable characteristics. They accomplish automated, 3D hybrid microassembly (i.e., assembly of post-fabricated parts from different materials) and packaging (i.e., bonding, sealing and interconnects).

Now, Dr. Popa is extending these results to the nano scale by combining manipulation with self-assembly through small robotic systems on a wafer. Recently, Dr. Popa and his students have built and demonstrated two nano-robots.

The “ARRIpede” (shown below) is an autonomous microcrawler/conveyor supported by micro-legs and carrying an electronics backpack containing a surface-mount technology-mounted boost converter, a DSP controller circuit and a polymer battery power source. The robot can be operated as a conveyor (“belly-up”) or as a crawler (“belly-down”).

Another of his team’s creations is one of the world’s most dexterous sub-millimeter, 3D assembled nanomanipulators for sample characterization inside a Scanning Electron Microscope chamber. These robots were recently described at the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 2008 in Nice, France and the 6th International Workshop of Microfactories 2008 in Evanston, Illinois. IROS is one of the two largest robotics meetings worldwide.

For more information on Dr. Popa’s work, visit http://arri.uta.edu/popa.