Support and actuation of the segmented primary mirror of the E-ELT Dr.ir. Gert Witvoet.

Support and actuation of the segmented primary mirror of the E-ELT

Dr.ir. Gert Witvoet

Dr.ir. Gert WitvoetM1SS and PACT for E-ELT

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What is TNO?

Netherlands organisation for applied scientific research

Founded by law in 1932

About 3000 employees

February 02, 2015


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TNO mission

TNO connects people and knowledge to create innovations that boost

the competitive strength of industry and the well-being of society in a

sustainable way.

TNO bridges the gap between academia and industry

We do this by

Consultancy

Contract research

Testing and certification

Licences

Performing statutory assignments

February 02, 2015


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TNO Optomechatronics (OM)

Offering optimal multi-disciplinary solutions to high-precision problems

synergy between various disciplines

Focus on design and realization of OM equipment

high-end single piece prototypes / instruments

February 02, 2015


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Application domains

Semicon

Space

Astronomy

Big science

Metrology / inspection

Medical

Manufacturing equipment

Oil & gas

….

February 02, 2015


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European Extremely Large Telescope (E-ELT)

February 02, 2015


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Inside the E-ELT

February 02, 2015

Will be the largest ground-based telescope in optical

and near IR range


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E-ELT: the primary mirror

Total diameter: 39.3 m

798 hexagonal segments of 1.4 m

corner-to-corner (1.2 m flat-to-flat)

6 identical mirror segment sets (M1)

One support system (M1SS) for 133

different mirror segments

Passive and active compensation of

surface form deformations of

individual segments

Active co-alignment of segments via

piston-tip-tilt actuators

February 02, 2015


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TNO’s ambition for E-ELT

Get Dutch industry involved

Via design and realization of

M1 support structure (M1SS)

Segment actuators (PACT)

February 02, 2015


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TNO M1SS design

February 02, 2015


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TNO Position Actuator (PACT) design

Some requirements:

Static load: 0 – 900 N

Operating angles: 0 – 90°

Stroke: 15 mm

Tracking velocity: 1.2 μm/s

Positioning accuracy: 1.7 nm RMS

while tracking

in presence of ground and wind disturbances

February 02, 2015


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PACT test program

E-ELT relevant test setup

allows 360° angular testing

90 kg test mass inside

passive suppression of ground vibrations

February 02, 2015


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PACT dynamics

Clean dynamics up to nearly 400 Hz

Constant dynamics over full 15 mm stroke

February 02, 2015


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PACT controller design

High-bandwidth control on fine stage

Low-bandwidth control on coarse stage

for off-loading fine stage force

February 02, 2015


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Measured tracking performance

Spectrum over 0.5 mm back and forth, 1.2 μm/s

February 02, 2015

1.4 nm RMS!


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Current work: M1SS-PACT assembly

February 02, 2015


17February 02, 2015

Support and actuation of the segmented primary mirror of the E-ELT Dr.ir. Gert Witvoet.

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