Scientists demonstrate a robotic muscle 1,000 times more powerful than a human's
By Nick Lavars
December 23, 2013
If a so-called "rise of the machines" ever comes to fruition, our chances of survival may have just taken a big hit. A team of scientists from the US Department of Energy ’s Lawrence Berkeley National Laboratory has demonstrated a new type of robotic muscle with 1,000 times more power than that of a human's, and the ability to catapult an item 50 times its own weight.
The artificial muscle was constructed using the material vanadium dioxide, known for its ability to rapidly change size and shape. The team, working with a silicone substrate, formed a V-shaped ribbon comprising chromium and vanadium dioxide, which formed a coil when released from the substrate. The coil when heated turned into a micro-catapult with the ability to hurl objects, or a proximity sensor, in which its remote sensing of an object causes a rapid change or micro-explosion in the muscle’s resistance and shape, pushing the object away.
"We’ve created a micro-bimorph dual coil that functions as a powerful torsional muscle, driven thermally or electro-thermally by the phase transition of vanadium dioxide," said the project’s leader Junqiao Wu in a press statement. "Using a simple design and inorganic materials, we achieve superior performance in power density and speed over the motors and actuators now used in integrated micro-systems."
Vanadium dioxide boasts several useful qualities for creating miniaturized artificial muscles and motors. An insulator at low temperatures, it abruptly becomes a conductor at 67° Celsius (152.6° F), a quality which drives its reputation as a potential solution to more energy efficient electronic devices. In addition, the vanadium dioxide crystals undergo a change in their physical form when warmed, contracting along one dimension while expanding along the other two.
During this experiment, the vanadium dioxide muscles displayed a rotational speed of 200,000 rpm, an amplitude of 500 to 2,000 degrees per millimeters in length and an energy power density of up to approximately 39 kilowatts per kilogram, figures that Wu says are unprecedented.
"These metrics are all orders of magnitudes higher than existing torsional motors based on electrostatics, magnetics, carbon nanotubes or piezoelectrics," he said. "With its combination of power and multi-functionality, our micro-muscle shows great potential for applications that require a high level of functionality integration in a small space."
You can see both the "hurling" and the "micro-explosion" abilities of the muscle in the video below.
The team's research is published in the online version of Advanced Materials
Source: Berkeley Lab
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