On the pages of our website one can find a lot of material devoted to tiny and light flying robots, living prototypes of which design are insects of different species. With a few exceptions, all such robots fly using energy supplied by the thinnest of electrical wires, which greatly limits the practical use of such devices. This drawback is completely eliminated by the new robot, which is virtually identical in appearance to its predecessors. The only and most important exception is that the tiny flying machine gets the power it needs by using wireless RF technology.
Built by Toyota's Central R&D Lab, the flying robot has six wings powered by a single piezoelectric actuator, an electronics unit and a 5GHz dipole antenna that converts radio wave energy into electricity. This antenna and the rest of the electronics provide a remarkable power-to-weight ratio of 4,900W*kg^-1.
The key problem faced by Japanese researchers, and faced by other developers of such miniaturised technology, is the heating of some components caused by the inevitable loss of energy during its conversion. To overcome this problem, the Japanese researchers optimised the robot's electronic circuitry and positioned the main heat-generating components as far away from each other as possible, allowing the heat to be dissipated as efficiently as possible into the environment.
"Our major achievement is the development of a circuit whose components weigh less than one gram, capable of receiving and handling more than one watt of power transmitted across the distance using directional radio waves," the researchers wrote, "Using the same technology, not only flying robots can be powered, but also other devices that require a significant amount of power."
During tests, whose main purpose was to test wireless power transmission systems, Japanese researchers were able to lift a flying robot into the air, which hovered in place and was able to stay there for an unlimited amount of time.
The Japanese-made robot weighs just 1.8 grams, at least 25 times lighter than other similar devices with wireless RF power transmission systems. And thanks to its small size, it can operate in extremely confined environments, such as inside pipelines, looking for cracks and defects.
"Our next step will be to couple the wireless power transmission system with a controller that receives commands with the same radio waves and controls the robot's flight parameters," the researchers write, "This will allow the robot not only to hover in one place but also to fly freely in all possible directions. We believe that this is already technically feasible at this time.