Application of Magneto-Rheological Finishing (MRF®) to the Figuring of Adaptive Optics Systems

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.

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Parametric Study of Damping Characteristics of Magneto-Rheological Damper: Mathematical and Experimental Approach

Pollack Periodica ◽

10.1556/606.2020.15.3.4 ◽

2020 ◽

Vol 15 (3) ◽

pp. 37-48

Author(s):

Zubair Rashid Wani ◽

Manzoor Ahmad Tantray

Keyword(s):

Structural Control ◽

Research Work ◽

Testing Machine ◽

Input Voltage ◽

Damping Coefficient ◽

Control Technique ◽

Damping Force ◽

Active Devices ◽

Active Structural Control ◽

Magneto Rheological

The present research work is a part of a project was a semi-active structural control technique using magneto-rheological damper has to be performed. Magneto-rheological dampers are an innovative class of semi-active devices that mesh well with the demands and constraints of seismic applications; this includes having very low power requirements and adaptability. A small stroke magneto-rheological damper was mathematically simulated and experimentally tested. The damper was subjected to periodic excitations of different amplitudes and frequencies at varying voltage. The damper was mathematically modeled using parametric Modified Bouc-Wen model of magneto-rheological damper in MATLAB/SIMULINK and the parameters of the model were set as per the prototype available. The variation of mechanical properties of magneto-rheological damper like damping coefficient and damping force with a change in amplitude, frequency and voltage were experimentally verified on INSTRON 8800 testing machine. It was observed that damping force produced by the damper depended on the frequency as well, in addition to the input voltage and amplitude of the excitation. While the damping coefficient (c) is independent of the frequency of excitation it varies with the amplitude of excitation and input voltage. The variation of the damping coefficient with amplitude and input voltage is linear and quadratic respectively. More ever the mathematical model simulated in MATLAB was in agreement with the experimental results obtained.

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Adaptive optics with adaptive filtering and control

Proceedings of the 2004 American Control Conference ◽

10.23919/acc.2004.1384398 ◽

2004 ◽

Author(s):

Yu-Tai Liu ◽

S. Gibson

Keyword(s):

Adaptive Optics ◽

Adaptive Filtering ◽

And Control

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Accounting for mirror dynamics in optimal Adaptive Optics control

2009 European Control Conference (ECC) ◽

10.23919/ecc.2009.7074944 ◽

2009 ◽

Cited By ~ 1

Author(s):

Carlos Correia ◽

Henri-Francois Raynaud ◽

Caroline Kulcsar ◽

Jean-Marc Conan

Keyword(s):

Adaptive Optics

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The Condition for Absolute Stability of an Electroelastic Actuator Control System for Nanomechatronics

Elektrichestvo ◽

10.24160/0013-5380-2020-10-52-58 ◽

2020 ◽

Vol 10 (10) ◽

pp. 52-58

Author(s):

Sergey M. AFONIN ◽

Keyword(s):

Control System ◽

Adaptive Optics ◽

Absolute Stability ◽

Deformation Characteristic ◽

Straight Line Segment ◽

Control Mechanisms ◽

Relative Width ◽

Random Inputs ◽

Deformation Control ◽

Actuator Control

An electroelastic actuator for nanomechatronics is used in nanotechnology, adaptive optics, microsurgery, microelectronics, and biomedicine to actuate or control mechanisms, systems based on the electroelastic effect, and to convert electrical signals into mechanical displacements and forces. In nanomechatronic systems, a piezoactuator is used in scanning microscopy, laser systems, in astronomy for precision alignment, for compensation of temperature, gravitational deformations and atmospheric turbulence, focusing, and stabilizing the image. In this study, a condition for absolute stability of an electroelastic actuator control system for nanomechatronics under deterministic and random inputs is obtained. A number of equilibrium positions in an electroelastic actuator mechatronic control system are found, the totality of which is represented by a straight line segment. The electroelastic actuator’s deformation control system dead band relative width is determined for the actuator’s symmetric and asymmetric hysteresis characteristics. Under deterministic inputs and with fulfilling the condition for the derivative of the nonlinear hysteresis actuator deformation characteristic, the set of equilibrium positions of the electroelastic actuator control system for nanomechatronics is absolutely stable. Under random inputs, the system absolute stability with respect to the mathematical expectations of the electroelastic actuator mechatronic control system equilibrium positions has been determined subject to fulfilling the condition on the derivative of the actuator hysteresis characteristic.

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