Physicists at the Monash University in Australia have developed a tiny motor that would be able to power a probe swimming through blood vessels. The device is about a quarter of a millimeter wide and utilizes a dual-action piezoelectric motor to drive small fan that pushes the unit forward.
From the Institute of Physics:
As Professor James Friend, leader of the research team at Monash University, explained, motors have lagged behind in the age of technological miniaturisation and provide the key to making robots small enough for injection into the bloodstream. “If you pick up an electronics catalogue, you’ll find all sorts of sensors, LEDs, memory chips, etc that represent the latest in technology and miniaturisation. Take a look however at the motors and there are few changes from the motors available in the 1950s.”
Professor Friend and his team began their research over two years ago in the belief that piezoelectricity was the most suitable energy force for micro-motors because the engines can be scaled down while remaining forceful enough, even at the sizes necessary to enter the bloodstream, for motors to swim against the blood’s current and reach spots difficult to operate upon.
Piezoelectricity is most commonly found in quartz watches and gas stoves. It is based on the ability of some materials to generate electric potential in response to mechanical stress. In the case of a gas stove, the ignition switch on a stove triggers a spring to release a ball that smashes against a piece of piezoelectric material, often kinds of crystal, which translates the force of the ball into more than 10,000 volts of electricity which then travels down wires, reaches the gas, and starts the stove fire.
As Professor Friend explains, “Opportunities for micro-motors abound in fields as diverse as biomedicine, electronics, aeronautics and the automotive industry. Responses to this need have been just as diverse, with designs developed using electromagnetic, electrostatic, thermal and osmotic driving forces. Piezoelectric designs however have favourable scaling characteristics and, in general, are simple designs, which have provided an excellent platform for the development of micro-motors.”
The team has produced prototypes of the motors and is now working on ways to improve the assembly method and the mechanical device which moves and controls the micro-motors.
Institute of Physics press release: Microbot motors fit to swim human arteries
Image: A lab bench prototype of the new motor. Applying voltage to the piezoelectric material sets up vibrations that the stator translates into a rotation of the ball – a design that could be shrunk further to drive small robots inside the body, its creators say (IOP/Monash University)