Expertise gained in building space telescopes has been transferred to wind turbines to cancel out vibrations before they become noise.
The European Space Agency’s (ESA) advanced Darwin planet-hunter study was used by a wind turbine maker to make sure it can generate power without making a noise by using the same approach that keeps multiple telescope mirrors precisely aligned – and quiet.
“Certain countries set certain limits on the amount of noise a turbine can make,” explains Nicolas Loix, CEO of Micromega Dynamics, a Belgian company whose main business includes controlling the vibrations.
Wind turbine noises can be either motorway-like drone from the blades or an irregular shriek from the gearbox. This is known as tonality, which can be more perceptible than broadband whirring noises, for example. Until now governments have been very strict over noise regulation and often the only way of keeping the countryside quiet has been to operate the machines at less than full power.
“Turbine manufacturers don’t like tonality. When customers face these kinds of problems, usually it’s late in the design phase. We have very little time to solve the problem,” said Loix.
The wind turbine company worked with ESA in the past on a telescope designed to monitor exoplanets in the Darwin project - designed to search for Earth-like planets around other stars and analyse their atmospheres for chemical signatures of life.
However, as it was not possible to build a giant telescope in space, several smaller telescopes had to combine their power to create the effect of a larger instrument, with the mirrors of each small telescope permanently aligned.
To move the mirrors, Micromega developed a high-precision mechanism using magnetic bearings. This mechanism would adjust the mirrors under the exacting circumstances of space, which required that the bearings work with high precision, zero friction and at very low temperatures.
They then applied the same science to an actuator to quieten the wind turbines. “The space project gave us confidence in our simulation tools,” said Liox. “We could not transpose the technology directly, but the knowledge we developed in space made us much faster.”