Segmented bimorph mirrors for adaptive optics: segment design and experiment

Bastaits, Renaud; Alaluf, David; Horodincă, Mihăiţă; Romanescu, Iulian Ilie; Burda, Ioan; Martic, Grégory; Rodrigues, Gonçalo; Preumont, André

doi:10.1364/ao.53.006635

Cited by 23 publications

(8 citation statements)

References 11 publications

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“…Most of them focus on mechanical isolation of the noisy equipment and/or of the sensitive payload from the rest of the spacecraft structure [11][12][13][14][15][16][17]. For some observation missions, active and adaptive optics [18][19][20] are a promising technology to perform wavefront correction and improve pointing stability at the payload level. Another complementary strategy is to actively control the spacecraft structure itself and limit its ability to propagate microvibrations.…”

Section: Background and Motivationmentioning

confidence: 99%

Robust and adaptable dynamic response reshaping of flexible structures

Preda

Sanfedino

Bennani

et al. 2020

Journal of Sound and Vibration

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This paper outlines a complete methodology for designing a control system that reshapes the dynamic response of the flexible structure to robustly match the dynamics of a given adaptable reference model. The procedure was experimentally verified on a setup developed at the European Space Agency, consisting of a cantilevered flexible plate actuated by two shakers. Angular displacements at the free tip of the plate were measured with sub-microradian resolution using a laser autocollimator. Following a comprehensive system identification phase, mathematical models of the uncertain plant were extracted. The models reliably fit the experimental data and were used to synthesize a low order and high bandwidth structured Linear Parameter Varying controller. The controller was designed by taking into account the limits of achievable performance and the closed loop effectively constrained the flexible structure to behave like it was made out of an adaptable material. The robust stability and worst case performances were assessed by means of a structured singular value analysis and excellent agreement between theoretical predictions and experimental results was observed.

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Section: Background and Motivationmentioning

confidence: 99%

Robust and adaptable dynamic response reshaping of flexible structures

Preda

Sanfedino

Bennani

et al. 2020

Journal of Sound and Vibration

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“…If the front-side ring actuators are introduced in the Jacobian J, the thermal control is integrated with atmospheric turbulence in the shape control ( Figure 3). In Figure 7c, the residual surface figure error consists of an array of dimples; their amplitude is related to the gap between the electrodes [9].…”

Section: Thermal Deformations Tip-tilt Controlmentioning

confidence: 99%

Thermal Balance and Active Damping of a Piezoelectric Deformable Mirror for Adaptive Optics

2019

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Piezoelectric unimorph deformable mirrors offer a cheap solution to adaptive optics, with mass production capability. However, standard solutions have significant drawbacks: (i) the static shape is sensitive to the temperature, and (ii) the low structural damping limits the control bandwidth, because of the interaction between the shape control and the vibration modes of the mirror. This paper discusses how these two problems may be alleviated by using a mirror covered with an array of actuators working in d31 mode on the back side and a ring of transducers (actuators and sensors) on the front side, outside the pupil of the mirror.

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“…It describes the various layers composing the deformable mirror as well as their respective thicknesses. To account for the fact that PZT cannot be actuated with plus and minus voltages, the PZT wafer was glued (with space-qualified glue EPO-TEK-301) under voltage according to the technique described in [19], so that the initial shape of the mirror is concave and the normal operating range of the deformable mirror is symmetric with respect to an initial bias necessary to remove the initial concave curvature.…”

Section: Designmentioning

confidence: 99%

Damping of piezoelectric space instruments: application to an active optics deformable mirror

et al. 2019

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This paper presents the shunt damping of a unimorph piezoelectric mirror intended to be used as an active secondary corrector in future space telescopes. We propose to take advantage of the actuation capability of the piezoelectric mirror, to increase its natural damping during the critical launch phase of the spacecraft. The piezoelectric actuators, intended to be used for active optics, are shunted on a passive resistive and inductive RL circuit during the launch operation. The proposed concept is verified numerically and experimentally on a piezoelectric deformable mirror prototype, developed on behalf of the European Space Agency. We show that the shunt damping significantly reduces the response of the most critical mode of the mirror (− 23 dB) as well as the stress in the mirror when subjected to a typical vibro-acoustic launch load. This reduces the risk of damaging the mirror during the delicate launch phase, without increasing the complexity of the design.

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Segmented bimorph mirrors for adaptive optics: segment design and experiment

Cited by 23 publications

References 11 publications

Robust and adaptable dynamic response reshaping of flexible structures

Robust and adaptable dynamic response reshaping of flexible structures

Thermal Balance and Active Damping of a Piezoelectric Deformable Mirror for Adaptive Optics

Damping of piezoelectric space instruments: application to an active optics deformable mirror

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