Selex ES, Edinburgh
CASE STUDY
University of the West of Scotland’s (UWS) School
of Science recently collaborated with Selex ES.
UWS and Selex ES were awarded a concept grant
worth £5k from the Scottish Funding Council (SFC)
to research sensor-enabled high dioptre
deformable mirror systems. The project was
managed by Professor Katherine Kirk, a member
of staff with considerable experience of new
product development projects across a range of
industries and technologies.
Selex ES is an international leader in electronic
and information technologies for defence
systems, aerospace, data, infrastructures, land
security and protection and sustainable ’smart’
solutions. From the design, development and
production of state-of-the-art equipment,
software and systems to through life support,
Selex ES partners with its customers to deliver the
information superiority required to act decisively,
complete missions and maintain security and
protection for operational effectiveness.
While the primary application area for this
technology was with SELEX: the research has the
potential to impact the performance of its optical
systems. An additional application area has
been identified in optics for retinal scanning
systems, and there is potential to engage with
businesses in this area following the completion
of the project.
Company Identified Problem
Selex Galileo had a requirement for a mirror/sensor
system capable of high dioptre optical correction.
Quality of optical components and sub systems can be
degraded through an accumulation of tolerances and
material inhomogeneities. Significant savings can be
made by providing a dynamic optical correction that
allows a relaxation of manufacturing tolerance, resulting
in savings on critical alignment and enabling the use of
more cost-effective components and raw materials.
Selex required corrective optics extending well beyond
the capability of current adaptive optics designs. UWS,
with its ability to develop a sensor-enabled precision
corrective optic, proposed a solution which could be
incorporated into existing designs – to have the flexibility
to vastly extend the range of correction, as well as
monitor environmental change. Initial thermal distortions
will be able to be tracked, thus allowing the equipment
to be used before its normal warm up is complete. For
field equipment this has an advantage in reducing
battery power consumption.
University Identified Solution
The overall aim was to produce a deformable mirror
system for low order, high dioptre optical correction.
Applications of this technology are in high power
lasers, ophthalmology, and microscopy. High power
lasers can suffer from start-up distortion caused by
varying lens power due to thermal effects in the laser
crystal, which prolongs the time for the laser to reach its
full brightness. A deformable mirror can correct the
distortion. Self-sensing incorporated into the mirror
forces a more rapid response time using electronic
control.
The challenge was to establish the feasibility and
manufacturability of the self-sensing mirror system by
experiment and simulation, using UWS’ expertise in
electromechanical design, actuator extension sensing
and deformable mirror technology. The industrial end
user needs a system that is robust, integrated, and low
cost. The benefit of extension sensing is to reduce the
hysteresis in the actuator response from a typical value
of 20% to less than 1%.
Conclusions
Selex ES provided experimental data about the beam
shape of its laser as well as specifications on the mirror
dimensions and required correction. This information
formed a basis for finite element simulations carried out
by University of the West of Scotland. Physical analysis
and experimental testing of a commercial piezo
bender actuator was also carried out by University of
the West of Scotland.
At the end of the project the industrial partner took part
in a round-up meeting at UWS, attended by the
Research Engineer from Selex ES and the company’s
University Liaison and Emerging Technologies
Manager. Following this a final report was produced
by University of the West of Scotland.
Feasibility has been established for extension sensing in
the bimorph type deformable mirror, plus confirmation
of achieving the required optical correction.
The next steps are (a) to investigate at the extension
sensing applied to deformation mapping of the
bimorph deformable mirror by experiment and
modelling, and subsequently (b) to design a custom
actuator structure for construction of a prototype
deformable mirror system.
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