Actuator influence functions of active mirrors

Menikoff, Arthur

doi:10.1364/ao.30.000833

Cited by 20 publications

(21 citation statements)

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“…5). This effect can be eliminated by use of a more accurate model, for example, finite-element analysis (FEA) [53], that incorporates the material properties of the corrector such as thickness, modulus of elasticity, and Poisson's ratio that determine the influence functions and ultimately mirror shape [54][55][56]. Such analysis, however, must be customized for a particular wavefront corrector, an approach not readily applicable for the many corrector configurations evaluated here.…”

Section: A Required Actuator Strokementioning

confidence: 99%

Requirements for discrete actuator and segmented wavefront correctors for aberration compensation in two large populations of human eyes

et al. 2007

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Numerous types of wavefront correctors have been employed in adaptive optics (AO) systems for correcting the ocular wavefront aberration. While all have improved image quality, none have yielded diffraction-limited imaging for large pupils (≥6 mm), where the aberrations are most severe and the benefit of AO the greatest. To this end, we modeled the performance of discrete actuator, segmented piston-only, and segmented piston/tip/tilt wavefront correctors in conjunction with wavefront aberrations measured on normal human eyes in two large populations. The wavefront error was found to be as large as 53 μm, depending heavily on the pupil diameter (2-7.5 mm) and the particular refractive state. The required actuator number for diffraction-limited imaging was determined for three pupil sizes (4.5, 6, and 7.5 mm), three second-order aberration states, and four imaging wavelengths (0.4, 0.6, 0.8, and 1.0 μm). The number across the pupil varied from only a few actuators in the discrete case to greater than 100 for the piston-only corrector. The results presented will help guide the development of wavefront correctors for the next generation of ophthalmic instrumentation.

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Section: A Required Actuator Strokementioning

confidence: 99%

Requirements for discrete actuator and segmented wavefront correctors for aberration compensation in two large populations of human eyes

et al. 2007

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“…With the presented methods, both numerically and analytically derived eigenmodes of deformable plates can be used to determine minimum force actuator positions for a limited number of actuators. With analytically derived actuator influence functions [17], the actuator placement can be evaluated with respect to optical specifications and refined if necessary. In this framework, the actuators considered may either be of displacement type or of force type.…”

Section: Introductionmentioning

confidence: 99%

Actuator placement for minimum force modal control of continuous faceplate deformable mirrors

Ruppel

Sawodny

2010

2010 IEEE International Conference on Control Applications

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A mechanically motivated strategy for determining actuator locations for minimum force modal control of continuous faceplate deformable mirrors in adaptive optics systems is proposed. It is shown that numerically or analytically derived eigenmodes of deformable mirrors can be used to determine optimal positions for a limited number of actuators. The actuators considered in this framework may either be of displacement type or of force type. Moreover, the presented methodology can be adapted to momentum actuators.

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“…In recent years, micromachined membrane deformable mirrors (MMDM) provide a low cost and compact solution for the AO systems (Claflin and Bareket 1986). Influence functions are used to represent the deformation shape of the thin elastic plate type mirrors (Menikoff 1991). The highly nonlinear nature of electrostatic forces requires nonlinear computation in modeling deformation by nonlinear partial differential equations (Wang and Hadaegh 1996).…”

Section: Introductionmentioning

confidence: 99%

Shape optimizations and static/dynamic characterizations of deformable microplate structures with multiple electrostatic actuators

Packirisamy

Bhat

2007

Microsyst Technol

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Micromirrors used in many optoelectronic devices can be considered as microplates. The functions and accuracy of the micromirrors depend on the static and dynamic deflection shapes of microplates. The objective of this study is to develop an efficient method for predicting the shapes of the microplates subjected to unsymmetrical electrostatic forces produced by electrostatic actuators such that micromirrors can be effectively optimized and controlled in their real time operation. The non-classical boundary conditions which result from the microfabrication process were modeled with artificial springs at the edges. A classical energy method using boundary characteristic orthogonal polynomials was applied to formulate the equations of motion of the microsystem. Based on this method, influence functions were built and least squares method was used to optimize the desired deflection under electrostatic forces from the electrostatic actuators. Softening effect of the electrostatic stiffness was also evaluated and considered in the simulation. Static deflections and dynamic responses were compared with those from finite element analysis (FEA) using Reduced Order Modeling (ROM) method. This study found that the static and dynamic responses of microplates predicted from the proposed method were highly consistent with those calculated from FEA. However, the proposed method is simpler and more efficient than FEA and can be conveniently used for any non-classical boundary condition situations. These features make the proposed method useful to effectively control and optimize the shape of a microplate with multiple electrostatic actuators.

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Actuator influence functions of active mirrors

Cited by 20 publications

References 1 publication

Requirements for discrete actuator and segmented wavefront correctors for aberration compensation in two large populations of human eyes

Requirements for discrete actuator and segmented wavefront correctors for aberration compensation in two large populations of human eyes

Actuator placement for minimum force modal control of continuous faceplate deformable mirrors

Shape optimizations and static/dynamic characterizations of deformable microplate structures with multiple electrostatic actuators

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