ROBOBEE:FLYING ROBOT

RoboBee is a tiny robot capable of tethered flight, developed by a research robotics team at Harvard University. The culmination of twelve years of research, RoboBee solved two key technical challenges of micro-robotics. Engineers invented a process inspired by pop-up books that allowed them to build on a sub-millimetre scale precisely and efficiently. To achieve flight, they created artificial muscles capable of beating the wings 120 times per second.

The goal of the RoboBee project is to make a fully autonomous swarm of flying robots for applications such as search and rescue and artificial pollination. To make this feasible, researchers need to figure out how to get power supply and decision making functions, which are currently supplied to the robot via a tiny tether, on board.

Challenges: 

According to the RoboBee researchers, previous efforts to miniaturise robots were of little help to them because RoboBee's small size changes the nature of the forces at play.Engineers had to figure out how to build without rotary motors, gears, and nuts and bolts, which are not viable on such a small scale.In 2011, they developed a technique where they cut designs from flat sheets, layered them up, and folded the creation into shape. Glue was used to hold the folded parts together, analogous to origami. The technique replaced earlier ones that were slower and less precise and used less durable materials. The manufacturing process, inspired by pop-up books, enables the rapid production of prototype RoboBee units

At micro scale, a small amount of turbulence can have a dramatic impact on flight. To overcome it, researchers had to make RoboBee react very rapidly. For the wings, they built "artificial muscles" using a piezoelectric actuator - a thin ceramic strip that contracts when electric current is run across it.Thin plastic hinges serve as joints that allow rotational motions in the wings.The design allows the robots to generate power output comparable with an insect of equal size. Each wing can be controlled separately in real time.

The ultimate goal of the project is to make colonies of fully autonomous and wireless RoboBees. As of 2013, two problems remain unsolved. First, the robot is too small for even the smallest encapsulated microchips, meaning there is no way for the robots to make decisions. Currently, the RoboBee has on board vision sensors, but the data requires transmission to a tethered "brain subsystem" for interpretation. Work continues on specialised hardware accelerators in an aim to solve the problem.

Second, the researchers have not figured out how to get a viable power supply on board. "The power question also proves to be something of a catch-22", remarked Wood. "A large power unit stores more energy but demands a larger propulsion system to handle the increased weight, which in turn requires an even bigger power source." Instead the robots have to be tethered with tiny cords that supply power and directions. A recent progress in on-board power management is the demonstration of reversible, energy-efficient perching on overhangs. This allows the prototype to remain at a high vantage point while conserving energy.