A Comprehensive Survey on Microgrippers Design: Operational Strategy
01 Jul 2017-Journal of Mechanical Design (American Society of Mechanical Engineers Digital Collection)-Vol. 139, Iss: 7, pp 070801
About: This article is published in Journal of Mechanical Design.The article was published on 2017-07-01. It has received 66 citations till now.
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TL;DR: The design, modelling, fabrication and experimental testing of an electrothermal microgripper based on a ‘hot and cold arm’ actuator design that is suitable for the deformability characterisation of human red blood cells (RBCs) are presented.
Abstract: Microgrippers are typical microelectromechanical systems (MEMS) that are widely used for micromanipulation and microassembly in both biological and micromanufacturing fields. This paper presents the design, modelling, fabrication and experimental testing of an electrothermal microgripper based on a ‘hot and cold arm’ actuator design that is suitable for the deformability characterisation of human red blood cells (RBCs). The analysis of the mechanical properties of human RBCs is of great interest in the field of medicine as pathological alterations in the deformability characteristics of RBCs have been linked to a number of diseases. The study of the microgripper’s steady-state performance is initially carried out by the development of a lumped analytical model, followed by a numerical model established in CoventorWare® (Coventor, Inc., Cary, NC, USA) using multiphysics finite element analysis. Both analytical and numerical models are based on an electothermomechanical analysis, and take into account the internal heat generation due to the applied potential, as well as conduction heat losses through both the anchor pads and the air gap to the substrate. The models are used to investigate key factors of the actuator’s performance including temperature distribution, deflection and stresses based on an elastic analysis of structures. Results show that analytical and numerical values for temperature and deflection are in good agreement. The analytical and computational models are then validated experimentally using a polysilicon microgripper fabricated by the standard surface micromachining process, PolyMUMPs™ (Durham, NC, USA). The microgripper’s actuation is characterised at atmospheric pressure by optical microscopy studies. Experimental results for the deflection of the microgripper arm tips are found to be in good agreement with the analytical and numerical results, with process-induced variations and the non-linear temperature dependence of the material properties accounting for the slight discrepancies observed. The microgripper is shown to actuate to a maximum opening displacement of 9 μ m at an applied voltage of 3 V, thus being in line with the design requirement of an approximate opening of 8 μ m for securing and characterising a RBC.
31 citations
Cites background from "A Comprehensive Survey on Microgrip..."
...MEMS microgrippers have been the subject of numerous works in literature, focusing mainly on the microgripper’s design and mechanical structure [4], operational aspects [5], material selection [6], microfabrication [7–10], and applicability to diverse environments [11]....
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TL;DR: A new method for measuring the viscoelastic properties of soft materials at the microscale is proposed, based on the adoption of a microsystem whose mechanical structure can be reduced to a compliant four bar linkage where the connecting rod is substituted by the tissue sample.
Abstract: As many studies show, there is a relation between the tissue’s mechanical characteristics and some specific diseases. Knowing this relationship would help early diagnosis or microsurgery. In this paper, a new method for measuring the viscoelastic properties of soft materials at the microscale is proposed. This approach is based on the adoption of a microsystem whose mechanical structure can be reduced to a compliant four bar linkage where the connecting rod is substituted by the tissue sample. A procedure to identify both stiffness and damping coefficients of the tissue is then applied to the developed hardware. Particularly, stiffness is calculated solving the static equations of the mechanism in a desired configuration, while the damping coefficient is inferred from the dynamic equations, which are written under the hypothesis that the sample tissue is excited by a variable compression force characterized by a suitable wave form. The whole procedure is implemented by making use of a control system.
31 citations
TL;DR: In this paper, the potentialities of computationally efficient modeling techniques (1D FEA, PRB method and chained-beam constraint model), focusing on their applicability in nonstandard planar problems, are compared.
Abstract: Beam-based Compliant Mechanisms (CMs) are increasingly studied and implemented in precision engineering. Straight beams with uniform cross section are the basic modules in several design concepts, which can be deemed as standard CMs. Their behavioral analysis can be addressed with a large variety of techniques, including the Euler–Bernoulli beam theory, the Pseudo-Rigid Body (PRB) method, the beam constraint model and the discretization-based methods. This variety is unquestionably reduced when considering nonstandard CMs, namely design problems involving special geometries, such as curve/spline beams, variable section beams, nontrivial shapes and contact pairs. The 3D Finite Element Analysis (FEA) provides accurate results but its high computational cost makes it inappropriate for optimization purposes. This work compares the potentialities of computationally efficient modeling techniques (1D FEA, PRB method and chained-beam constraint model), focusing on their applicability in nonstandard planar problems. The cross-axis flexural pivot is used as a benchmark in this research due to its high configurable behavior and wide range of applications. In parallel, as an attempt to provide an easy-to-use environment for CM analysis and design, a multi-purpose tool comprising Matlab and a set of modern Computer-Aided Design/Engineering packages is presented. The framework can implement different solvers depending on the adopted behavioral models. Summary tables are reported to guide the designers in the selection of the most appropriate technique and software framework. Lastly, efficient design procedures that allow to configure nonstandard beam-based CMs with prescribed behavior are examined with two design examples.
26 citations
TL;DR: The development of a straight line path generator MEMS device is presented and a new procedure is suggested for avoiding branch or circuit problems in the kinematic synthesis problem.
Abstract: In this paper, a microsystem with prescribed functional capabilities is designed and simulated. In particular, the development of a straight line path generator MEMS device is presented. A new procedure is suggested for avoiding branch or circuit problems in the kinematic synthesis problem. Then, Ball’s point detection is used to validate the obtained pseudo-rigid body model (PRBM). A compliant Micro Electro Mechanical System (MEMS) device is obtained from the PRBM through the rigid-body replacement method, by making use of Conjugate Surfaces Flexure Hinges (CSFHs). Finally, the functional capability of the device is investigated by means of FEA simulations and experimental testing at the macroscale.
25 citations
TL;DR: A proper mechanical model is developed for the coupled nonlinear dynamics of the microsystem, composed of the measuring tool and the specimen to be analyzed, and the identification of the viscoelastic parameters is performed by implementing a genetic algorithm.
Abstract: In this paper, the viscoelastic characterization of biosamples is addressed considering a measuring technique relying on the use of a MEMS techonology-based microgripper. A proper mechanical model is developed for the coupled nonlinear dynamics of the microsystem, composed of the measuring tool and the specimen to be analyzed. The Maxwell liquid drop model and the generalized Maxwell-Wiechert model are considered for the sample, and the identification of the viscoelastic parameters is performed by implementing a genetic algorithm.
23 citations
References
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Book•
07 Jun 1995
TL;DR: Striking a balance between theory and applications, Linear System Theory and Design, 3/e, is ideal for use in advanced undergraduate/first-year graduate courses in linear systems and multivariable system design in electrical, mechanical, chemical, and aeronautical engineering departments.
Abstract: From the Publisher:
An extensive revision of the author's highly successful text, this third edition of Linear System Theory and Design has been made more accessible to students from all related backgrounds. After introducing the fundamental properties of linear systems, the text discusses design using state equations and transfer functions. The two main objectives of the text are to: use simple and efficient methods to develop results and design procedures; enable students to employ the results to carry out design. Striking a balance between theory and applications, Linear System Theory and Design, 3/e, is ideal for use in advanced undergraduate/first-year graduate courses in linear systems and multivariable system design in electrical, mechanical, chemical, and aeronautical engineering departments. It assumes a working knowledge of linear algebra and the Laplace transform and an elementary knowledge of differential equations.
4,017 citations
TL;DR: A new conceptually simple approach to controlling compliant motions of a robot manipulator that combines force and torque information with positional data to satisfy simultaneous position and force trajectory constraints specified in a convenient task related coordinate system is presented.
Abstract: A new conceptually simple approach to controlling compliant motions of a robot manipulator is presented. The 'hybrid' technique described combines force and torque information with positional data to satisfy simultaneous position and force trajectory constraints specified in a convenient task related coordinate system. Analysis, simulation, and experiments are used to evaluate the controller's ability to execute trajectories using feedback from a force sensing wrist and from position sensors found in the manipulator joints. The results show that the method achieves stable, accurate control of force and position trajectories for a variety of test conditions.
2,991 citations
Book•
01 Jan 2002
TL;DR: In this paper, a comparison of top-down and bottom-up manufacturing methods for micro-manufacturing is presented, with a focus on the use of micro-processors.
Abstract: LITHOGRAPHY Introduction Historical Note: Lithography's Origins Photolithography Overview Critical Dimension, Overall Resolution, Line-Width Lithographic Sensitivity and Intrinsic Resist Sensitivity (Photochemical Quantum Efficiency) Resist Profiles Contrast and Experimental Determination of Lithographic Sensitivity Resolution in Photolithography Photolithography Resolution Enhancement Technology Beyond Moore's Law Next Generation Lithographies Emerging Lithography Technologies PATTERN TRANSFER WITH DRY ETCHING TECHNIQUES Introduction Dry Etching: Definitions and Jargon Plasmas or Discharges Physical Etching: Ion Etching or Sputtering and Ion-Beam Milling Plasma Etching (Radical Etching) Physical/Chemical Etching PATTERN TRANSFER WITH ADDITIVE TECHNIQUES Introduction Silicon Growth Doping of Si Oxidation of Silicon Physical Vapor Deposition Chemical Vapor Deposition Silk-Screening or Screen-Printing Sol-Gel Deposition Technique Doctors' Blade or Tape Casting Plasma Spraying Deposition and Arraying Methods of Organic Layers in BIOMEMS Thin versus Thick Film Deposition Selection Criteria for Deposition Method WET BULK MICROMACHINING Introduction Historical Note Silicon Crystallography Silicon As Substrate Silicon As A Mechanical Element In MEMS Wet Isotropic And Anisotropic Etching Alignment Patterns Chemical Etching Models Etching With Bias And/Or Illumination Of The Semiconductor Etch-Stop Techniques Problems With Wet Bulk Micromachining SURFACE MICROMACHINING Introduction Historical Note Mechanical Properties of Thin Films Surface Micromachining Processes Poly-Si Surface Micromachining Modifications Non-Poly-Si Surface Micromachining Modifications Materials Case Studies LIGA AND MICROMOLDING Introduction LIGA-Background LIGA and LIGA-Like Process Steps A COMPARISON OF MINIATURIZATION TECHNIQUES: TOP-DOWN AND BOTTOM-UP MANUFACTURING Introduction Absolute and Relative Tolerance in Manufacturing Historical Note: Human Manufacturing Section I: Top-Down Manufacturing Methods Section II: Bottom-Up Approaches MODELING, BRAINS, PACKAGING, SAMPLE PREPARATION AND NEW MEMS MATERIALS Introduction Modeling Brains In Miniaturization Packaging Substrate Choice SCALING, ACTUATORS, AND POWER IN MINIATURIZED SYSTEMS Introduction Scaling Actuators Fluidics Scaling In Analytical Separation Equipment Other Actuators Integrated Power MINIATURIZATION APPLICATIONS Introduction Definitions and Classification Method Decision Three OVERALL MARKET For MICROMACHINES Introduction Why Use Miniaturization Technology ? From Perception to Realization Overall MEMS Market Size MEMS Market Character MEMS Based on Si Non-Silicon MEMS MEMS versus Traditional Precision Engineering The Times are a'Changing APPENDICES Metrology Techniques WWW Linkpage Etch Rate for Si, SiO2 Summary of Top-Down Miniaturization Tools Listing of names of 20 amino acids & their chemical formulas Genetic code Summary of Materials and Their Properties for Microfabrication References for Detailed Market Information on Miniature Devices MEMS Companies Update Suggested Further Reading Glossary Symbols used in Text INDEX Each chapter also contains sections of examples and problems
1,930 citations
Book•
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01 Jan 2001
TL;DR: In this article, a minor numerical error in going from Eq. 16.39 to eq.16.40 is found, which has an obvious effect on the calculations that follow, increasing the minimum detectable temperature change to about 2 mK.
Abstract: p. 445 There is a minor numerical error in going from Eq. 16.39 to Eq. 16.40. The factor of 2 in the 1/f term was omitted, so the correct numerator for the second term in Eq. 16.40 is 1.44 x 10 -7 . This error has an obvious effect on the calculations that follow, increasing the minimum detectable temperature change to about 2 mK (Eq. 16.44) and, correspondingly, increasing the RMS noise calculated from Eq. 16.49 by sqrt(2).
1,917 citations
TL;DR: In this article, the complete tensor piezoresistance has been determined experimentally for these materials and expressed in terms of the pressure coefficient of resistivity and two simple shear coefficients.
Abstract: Uniaxial tension causes a change of resistivity in silicon and germanium of both $n$ and $p$ types. The complete tensor piezoresistance has been determined experimentally for these materials and expressed in terms of the pressure coefficient of resistivity and two simple shear coefficients. One of the shear coefficients for each of the materials is exceptionally large and cannot be explained in terms of previously known mechanisms. A possible microscopic mechanism proposed by C. Herring which could account for one large shear constant is discussed. This so called electron transfer effect arises in the structure of the energy bands of these semiconductors, and piezoresistance may therefore give important direct experimental information about this structure.
1,779 citations