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R S Muller - One of the best experts on this subject based on the ideXlab platform.
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magnetic microactuation of torsional polysilicon structures
Sensors and Actuators A-physical, 1996Co-Authors: Jack W Judy, R S MullerAbstract:Abstract A microactuator technology utilizing magnetic thin films and polysilicon Flexures in applied to torsional microstructures. These structures are constructed in a batch-fabrication process that combines electroplating with conventional IC-lithography, materials, and equipment. A microactuated mirror made from a 430 μ m × 130 μ m × 15 μ m nickel-iron plate attached to a pair of 400 μ m × 2.2 μ m × 2.2 μ m polysilicon torsional beams has been rotated more than 90° out of the plane of the wafer and actuated with a torque greater than 3.0 nN m. The torsional Flexure structure constrains motion to rotation about a single axis, which can be an advantage for a number of microphonic applications (e.g., beam chopping, scanning, and steering).
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magnetic microactuation of torsional polysilicon structures
Proceedings of the International Solid-State Sensors and Actuators Conference - TRANSDUCERS '95, 1995Co-Authors: Jack W Judy, R S MullerAbstract:A microactuator technology utilizing magnetic thin films and polysilicon Flexures is applied to torsional micro structures. These structures are constructed in a batch-fabrication process that combines electroplating with conventional IC-lithography, materials, and equipment. A microactuated mirror made from a 430 x 130 x l5 /spl mu/m/sup 3/ nickel-iron plate attached to a pair of 400 x 2.2 x 2.2 /spl mu/m/sup 3/ polysilicon torsional beams has been rotated more than 90/spl deg/ out of the plane of the wafer and actuated with a torque greater than 3.0 nN-m. The torsional Flexure structure constrains motion to rotation about a single axis which can be an advantage for a number of microphotonic applications (e.g., beam chopping, scanning, and steering).
Jack W Judy - One of the best experts on this subject based on the ideXlab platform.
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magnetic microactuation of torsional polysilicon structures
Sensors and Actuators A-physical, 1996Co-Authors: Jack W Judy, R S MullerAbstract:Abstract A microactuator technology utilizing magnetic thin films and polysilicon Flexures in applied to torsional microstructures. These structures are constructed in a batch-fabrication process that combines electroplating with conventional IC-lithography, materials, and equipment. A microactuated mirror made from a 430 μ m × 130 μ m × 15 μ m nickel-iron plate attached to a pair of 400 μ m × 2.2 μ m × 2.2 μ m polysilicon torsional beams has been rotated more than 90° out of the plane of the wafer and actuated with a torque greater than 3.0 nN m. The torsional Flexure structure constrains motion to rotation about a single axis, which can be an advantage for a number of microphonic applications (e.g., beam chopping, scanning, and steering).
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magnetic microactuation of torsional polysilicon structures
Proceedings of the International Solid-State Sensors and Actuators Conference - TRANSDUCERS '95, 1995Co-Authors: Jack W Judy, R S MullerAbstract:A microactuator technology utilizing magnetic thin films and polysilicon Flexures is applied to torsional micro structures. These structures are constructed in a batch-fabrication process that combines electroplating with conventional IC-lithography, materials, and equipment. A microactuated mirror made from a 430 x 130 x l5 /spl mu/m/sup 3/ nickel-iron plate attached to a pair of 400 x 2.2 x 2.2 /spl mu/m/sup 3/ polysilicon torsional beams has been rotated more than 90/spl deg/ out of the plane of the wafer and actuated with a torque greater than 3.0 nN-m. The torsional Flexure structure constrains motion to rotation about a single axis which can be an advantage for a number of microphotonic applications (e.g., beam chopping, scanning, and steering).
Shorya Awtar - One of the best experts on this subject based on the ideXlab platform.
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Large range dual-axis micro-stage driven by electrostatic comb-drive actuators
Journal of Micromechanics and Microengineering, 2013Co-Authors: M. Olfatnia, Pankaj Chopra, Shorya AwtarAbstract:This paper presents a micro XY stage that employs electrostatic comb-drive actuators and achieves a bi-directional displacement range greater than 225 µm per motion axis. The proposed XY stage design comprises four rigid stages (ground, motion stage, and two intermediate stages) interconnected via Flexure modules. The motion stage, which has two translational degrees of freedom, is connected to two independent single degree of freedom intermediate stages via respective parallelogram (P) transmission Flexures. The intermediate stages are connected to the ground via respective clamped paired double parallelogram (C-DP-DP) guidance Flexures. The C-DP-DP Flexure, unlike conventional Flexures such as the paired double parallelogram Flexure (DP-DP), provides high bearing direction stiffness (Kb) while maintaining low motion direction stiffness (Km) over a large range of motion direction displacement. This helps delay the onset of sideways instability in the comb-drive actuators that are integrated with the intermediate stages, thereby offering a significantly greater actuation stroke compared to existing designs. The presented work includes closed-form stiffness analysis of the proposed micro-stage, finite elements simulation, and experimental measurements of its static and dynamic behavior.
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Note: an asymmetric Flexure mechanism for comb-drive actuators.
Review of Scientific Instruments, 2012Co-Authors: M. Olfatnia, Siddharth Sood, Shorya AwtarAbstract:This Note presents a new asymmetric Flexure design, the double parallelogram–tilted-beam double parallelogram (DP-TDP) Flexure, that enables two times higher stroke in electrostatic comb-drive actuators, compared to the traditional symmetrically paired double parallelogram (DP-DP) Flexure, while maintaining the same device footprint. Because of its unique kinematic configuration, the DP-TDP Flexure provides an improved stiffness ratio between the bearing and actuation directions, thus delaying the on-set of sideways instability. Experimental testing of micro-fabricated comb-drive actuators with Flexure beam length 1 mm and comb gap 5 μm demonstrates a stroke of 149 μm (at 86 V) for the proposed DP-TDP Flexure, in comparison to 75 μm (at 45 V) for the traditional DP-DP Flexure.
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A Generalized Constraint Model for Two-Dimensional Beam Flexures: Nonlinear Strain Energy Formulation
Journal of Mechanical Design, 2010Co-Authors: Shorya Awtar, Shiladitya SenAbstract:The beam constraint model (BCM), presented previously, captures pertinent nonlinearities to predict the constraint characteristics of a generalized beam Flexure in terms of its stiffness and error motions. In this paper, a nonlinear strain energy formulation for the beam Flexure, consistent with the transverse-direction load-displacement and axial-direction geometric constraint relations in the BCM, is presented. An explicit strain energy expression, in terms of beam end displacements, that accommodates generalized loading conditions, boundary conditions, initial curvature, and beam shape, is derived. Using energy-based arguments, new insight into the BCM is elucidated by fundamental relations among its stiffness, constraint, and energy coefficients. The presence of axial load in the geometric constraint and strain energy expressions—a unique attribute of distributed compliance Flexures that leads to the elastokinematic effect—is highlighted. Using the principle of virtual work, this strain energy expression for a generalized beam is employed in determining the load-displacement relations, and therefore constraint characteristics, of a Flexure mechanism comprising multiple beams. The benefit of this approach is evident in its mathematical efficiency and succinctness, which is to be expected with the use of energy methods. All analytical results are validated to a high degree of accuracy via nonlinear finite element analysis.
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a generalized constraint model for two dimensional beam Flexures nonlinear load displacement formulation
Journal of Mechanical Design, 2010Co-Authors: Shorya AwtarAbstract:To utilize beam Flexures in constraint-based Flexure mechanism design, it is important to develop qualitative and quantitative understanding of their constraint characteristics in terms of stiffness and error motions. This paper provides a highly generalized yet accurate closed-form parametric load-displacement model for two-dimensional beam Flexures, taking into account the nonlinearities arising from load equilibrium applied in the deformed configuration. In particular, stiffness and error motions are parametrically quantified in terms of elastic, load-stiffening, kinematic, and elastokinematic effects. The proposed beam constraint model incorporates a wide range of loading conditions, boundary conditions, initial curvature, and beam shape. The accuracy and effectiveness of the proposed beam constraint model is verified by nonlinear finite elements analysis.
Nicolae Lobontiu - One of the best experts on this subject based on the ideXlab platform.
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planar compliances of thin circular axis notch Flexure hinges with midpoint radial symmetry
Mechanics Based Design of Structures and Machines, 2013Co-Authors: Nicolae Lobontiu, Matt Cullin, Jeffrey HoffmanAbstract:The new class of Flexure hinges with circular longitudinal axis and midpoint radial symmetry is introduced. Using rotation and mirroring, the symmetric Flexure hinge is obtained from one half Flexure. The six planar-bending compliances of the full hinge are determined analytically for small deformations by combining only three compliances of the half Flexure. To illustrate the general Flexure hinge category, the novel circular-axis, right circularly corner-filleted design is introduced. Experimental and finite element results correlate well with the analytical model predictions. The new Flexure hinge design is compared to the circular-axis, constant-thickness Flexure and the straight-axis, right circularly corner-filleted hinge.
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Stiffness characterization of corner-filleted Flexure hinges
Review of Scientific Instruments, 2004Co-Authors: Nicolae Lobontiu, Ephrahim Garcia, Mihail HardauAbstract:The paper formulates the closed-form stiffness equations that can be used to characterize the static, modal, and dynamic behavior of single-axis corner-filleted Flexure hinges, which are incorporated into macro/microscale monolithic mechanisms. The derivation is based on Castiliagno’s first theorem and the resulting stiffness equations reflect sensitivity to direct- and cross-bending, axial loading, and torsion. Compared to previous analytical work, which assessed the stiffness of Flexures by means of compliances, this paper directly gives the stiffness factors that completely define the elastic response of corner-filleted Flexure hinges. The method is cost-effective as it requires considerably less calculation steps, compared to either finite element simulation or experimental characterization. Limit calculations demonstrate that the known engineering equations for a constant cross-section Flexure are retrieved from those of a corner-filleted Flexure hinge when the fillet radius becomes zero. The analytical model results are compared to experimental and finite element data and the errors are less than 8%. Further numerical simulation based on the analytical model highlights the influence of the geometric parameters on the stiffness properties of a corner-filleted Flexure hinge.
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Compliant Mechanisms: Design of Flexure Hinges
2002Co-Authors: Nicolae LobontiuAbstract:Preface INTRODUCTION COMPLIANCE-BASED DESIGN OF Flexure HINGES Introduction Generic Mathematical Formulation Single-Axis Flexure Hinges for Two-Dimensional Applications Multiple-Axis Flexure Hinges for Three-Dimensional Applications Two-Axis Flexure Hinges for Three-Dimensional Applications Conclusions STATICS OF Flexure-BASED COMPLIANT MECHANISMS Introduction Planar Compliant Mechanisms Spatial Compliant Mechanisms DYNAMICS OF Flexure-BASED COMPLIANT MECHANISMS Introduction Elastic Potential Energy for Individual Flexure Hinges Kinetic Energy for Individual Flexure Hinges Free and Forced Response of Flexure-Based Compliant Mechanisms Damping Effects FINITE ELEMENT FORMULATION FOR Flexure HINGES AND Flexure-BASED COMPLIANT MECHANISMS Introduction Generic Formulation Elemental Matrices for Flexure Hinges Elemental Matrices for Rigid Links Application Example Appendix TOPICS BEYOND THE MINIMAL MODELING APPROACH TO Flexure HINGES Large Deformations Buckling Torsion of Noncircular Cross-Section Flexure Hinges Composite Flexure Hinges Thermal Effects Shape Optimization Means of Actuation Fabrication APPLICATIONS OF Flexure-BASED COMPLIANT MECHANISMS Macroscale Applications Microscale (MEMS) Applications
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parabolic and hyperbolic Flexure hinges flexibility motion precision and stress characterization based on compliance closed form equations
Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2002Co-Authors: Nicolae Lobontiu, Jeffrey S. N. Paine, Edward Omalley, Marc SamuelsonAbstract:The parabolic and hyperbolic Flexure hinges are introduced as new rotation joints to be utilized in two-dimensional monolithic mechanisms. Closed-form equations are formulated for compliances to characterize both the active rotation and all other in- and out-of-plane parasitic motions. The stress levels are also evaluated in terms of compliances. Checked against finite element analysis and experimental measurement data, the model predictions are within 8% error margins. Further simulation is performed to compare geometrically-equivalent parabolic and hyperbolic Flexure hinges. The results indicate that the parabolic Flexures are more rotation-compliant and induce less stress, while the hyperbolic Flexures are less sensitive to parasitic effects.
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Corner-Filleted Flexure Hinges
Journal of Mechanical Design, 2000Co-Authors: Nicolae Lobontiu, Jeffrey S. N. Paine, Ephrahim Garcia, Michael GoldfarbAbstract:The paper presents an analytical approach to corner-filleted Flexure hinges. Closed-form solutions are derived for the in-plane compliance factors. It is demonstrated that the corner-filleted Flexure hinge spans a domain delimited by the simple beam and the right circular Flexure hinge. A comparison that is made with the right circular Flexure hinges indicates that the corner-filleted Flexures are more bending-compliant and induce lower stresses but are less precise in rotation. The finite element simulation and experimental results confirmed the model predictions.
Jianmin Miao - One of the best experts on this subject based on the ideXlab platform.
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influence of deep rie tolerances on comb drive actuator performance
Journal of Physics D, 2007Co-Authors: Bangtao Chen, Jianmin MiaoAbstract:This paper analyses the various etching tolerances and profiles of comb-drive microstructures by using deep reactive ion etching (RIE) and studies their influence on the actuator's performance. The comb-drive actuators studied in this paper are fabricated with the silicon-on-glass (SOG) wafer process using deep RIE and wafer bonding, which present very high-aspect-ratio and high-strength microstructures. However, the deep RIE process generates some tolerances and varies the dimension and profile of comb fingers and Flexures due to the process limitations. We have analysed the different etching tolerances and studied their influence on the actuator's performance, in terms of the electrostatic force, Flexure stiffness, actuator's displacement, air damping and quality factor of the actuator. The analysis shows that the comb fingers with a positive slope profile generated a larger electrostatic force, and the Flexures with a negative profile induced the loss of the actuator's stiffness. The combination of these two profiles leads to a great increase in the actuator's displacement and decrease in the quality factor. The measured results of the SOG fabricated actuators have demonstrated the influence of deep RIE tolerance on the actuator's performance.
