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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76 citations
TL;DR: A review of electrothermal micro-actuators and applications is presented in this paper, where the three main configurations of electro-thermal actuators are discussed: hot-and-cold-arm, chevron, and bimorph.
Abstract: This paper presents a review of electrothermal micro-actuators and applications. Electrothermal micro-actuators have been a significant research interest over the last two decades, and many different designs and applications have been investigated. The electrothermal actuation method offers several advantages when compared with the other types of actuation approaches based on electrostatic and piezoelectric principles. The electrothermal method offers flexibility in the choice of materials, low-cost fabrication, and large displacement capabilities. The three main configurations of electrothermal actuators are discussed: hot-and-cold-arm, chevron, and bimorph types as well as a few other unconventional actuation approaches. Within each type, trends are outlined from the basic concept and design modifications to applications which have been investigated in order to enhance the performance or to overcome the limitations of the previous designs. It provides a grasp of the actuation methodology, design, and fabrication, and the related performance and applications in cell manipulation, micro assembly, and mechanical testing of nanomaterials, Radio Frequency (RF) switches, and optical Micro-Electro-Mechanical Systems (MEMS).
66 citations
TL;DR: This paper is concentrated on reviewing the state-of-the-art research on complaint micro-/nano-positioning stage design in recent years and involves the major processes and components for designing a compliant positioning stage, e.g., actuator selection, stroke amplifier design, connecting scheme of the multi-DOF stage and structure optimization.
Abstract: Micromanipulation is a hot topic due to its enabling role in various research fields. In order to perform a high precision operation at a small scale, compliant mechanisms have been proposed and applied for decades. In microscale manipulation, micro-/nano-positioning is the most fundamental operation because a precision positioning is the premise of subsequent operations. This paper is concentrated on reviewing the state-of-the-art research on complaint micro-/nano-positioning stage design in recent years. It involves the major processes and components for designing a compliant positioning stage, e.g., actuator selection, stroke amplifier design, connecting scheme of the multi-DOF stage and structure optimization. The review provides a reference to design a compliant micro-/nano-positioning stage for pertinent applications.
59 citations
TL;DR: A CSFH has been analyzed with both theoretical and finite element methods, in order to obtain the relation between voltage and generated torque, and showed that CSFH performs better than linear flexure hinges in terms of larger rotations and less stress for given applied voltage.
Abstract: Progress in MEMS technology continuously stimulates new developments in the mechanical structure of micro systems, such as, for example, the concept of so-called CSFH (conjugate surfaces flexural hinge), which makes it possible, simultaneously, to minimize the internal stresses and to increase motion range and robustness. Such a hinge may be actuated by means of a rotary comb-drive, provided that a proper set of simulations and tests are capable to assess its feasibility. In this paper, a CSFH has been analyzed with both theoretical and finite element (FEM) methods, in order to obtain the relation between voltage and generated torque. The FEM model considers also the fringe effect on the comb drive finger. Electromechanical couple–field analysis is performed by means of both direct and load transfer methods. Experimental tests have been also performed on a CSFH embedded in a MEMS prototype, which has been fabricated starting from a SOI wafer and using D–RIE (deep reactive ion etching). Results showed that CSFH performs better than linear flexure hinges in terms of larger rotations and less stress for given applied voltage.
32 citations
TL;DR: In this article, the authors reviewed the recent advances on performance indices, classification, structural composition, optimization and modeling method, and control of PEACM and provided a guideline on further development of the micro gripper.
Abstract: The piezoelectric-actuated compliant microgripper (PEACM) plays an essential role in the application fields such as biomedical engineering, microelectronics, and optical engineering. As compared with other categories of grippers, PEACM exhibits the advantages of high accuracy of displacement, large power to weight ratio, low energy consumption, and fast response speed. This paper reviews the recent advances on performance indices, classification, structural composition, optimization and modeling method, and control of PEACM. First, the gripper's performance indices and classifications are elaborated, which is beneficial to determine the design goal. Then, the compliant mechanisms adopted in the microgripper design are discussed, including the flexible hinge, displacement amplifier, and guiding mechanism. In addition, the optimization and modeling methods of the microgripper are presented. Popular types of position/force sensors and different displacement/force control strategies employed in the microgripper are surveyed. Moreover, the prospect on future development trend of the PEACM is discussed. The paper provides the reader with an overview of the recent advances on PEACM design and also a guideline on further development of the microgripper.
32 citations
References
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TL;DR: A self-sensing method dedicated to free uni- and bimorph piezocantilevers but can also be adapted to other piezoactuator types, which has the ability to keep displacement information for long-term periods and in the reduction in signal noise.
Abstract: Piezoelectric meso- and microactuator systems required for manipulation or assembly of microscale objects demand reliable force and/or displacement information. Available sensors are prone to dimension restrictions or precision limitation. Self-sensing method, based on the electric charge measurement, may represent a solution in terms of cost-effectiveness and integration, the actuator performing simultaneously as its own sensor. This paper presents a self-sensing method dedicated to free uni- and bimorph piezocantilevers but can also be adapted to other piezoactuator types. The integrated electric current, used to convert the charge, can be compensated against piezoelectric material nonlinearities to provide accurate displacement information. The advantages relative to existing self-sensing methods consist in the ability to keep this displacement information for long-term periods (more than a thousand seconds) and in the reduction in signal noise. After introductive issues related to the method the base principle allowing the estimation of tip displacement is presented. Then, the identification procedure of the estimator parameters is depicted and representative experimental results are shown. Finally, a series of aspects related to electronic circuits are discussed, useful for successful system implementation.
74 citations
TL;DR: An overview of electro-thermal modeling of microsystems is presented in this paper, where the most important coupling between thermal and electrical phenomena is considered, and the industry's central concern is that of Joule heating.
Abstract: An overview of electro-thermal modeling of microsystems is presented. We consider the most important coupling between thermal and electrical phenomena, and then focus on the industry's central concern, that of Joule heating. A description of different solution approaches for the heat transfer partial differential equation, which constitutes the central part of electro-thermal simulation, is given. We briefly review the analytical solutions and consider further the numerical approaches, which are based on spatial discretization of the thermal domain. Lastly, we describe the final level of approximation, the dynamic compact thermal modeling. We emphasize the formal model order reduction methods, because they directly follow the spatial discretization, and thus preserve the investment into the finite element modeling.
73 citations
TL;DR: Two new approaches to regulating both position and contact force of a piezoelectric multimorph microgripper dedicated to microassembly tasks are presented, capable of accomplishing promising interaction control accuracy.
Abstract: Precision position and force control is a critical issue for automated microassembly systems to handle micro-objects delicately. This paper presents two new approaches to regulating both position and contact force of a piezoelectric multimorph microgripper dedicated to microassembly tasks. One of the advantages of the proposed approaches lies in that they are capable of controlling the position and contact force of a gripper arm simultaneously. The methodology is easy to implement since neither a state observer nor a hysteresis model of the system is required. The first approach is a position-based sliding mode impedance control which converts the target impedance into a desired position trajectory to be tracked, and the second one is established on the basis of a proportional-integral type of sliding function of the impedance measure error. Their tracking performances are guaranteed by two devised discrete-time sliding mode control algorithms, whose stabilities in the presence of model uncertainties and disturbances are proved in theory. The effectiveness of both schemes are validated by experimental investigations on a glass microbead gripping task. Results show that both approaches are capable of accomplishing promising interaction control accuracy.
71 citations
TL;DR: The experimental results show that the developed microgripper is capable of handling various sized micro-objects with a maximum jaw displacement of 134 μm and a high amplification ratio of 15.5.
Abstract: This paper describes the design, modeling, and testing of a novel flexure-based microgripper for a large jaw displacement with high resolution. Such a microgripper is indispensable in micro/nano manipulation. In achieving a large jaw displacement, double amplification mechanisms, namely, Scott-Russell mechanism and leverage mechanism arranged in series, are utilized to overcome the limited output of microgrippers driven by piezoelectric actuators. The mechanical performance of the microgripper is analyzed using the pseudo rigid body model approach. Finite element analysis is conducted to evaluate the performance and validate the established models for further optimum design of the microgripper. The prototype of the developed microgripper is fabricated, with which experimental tests are carried out. The experimental results show that the developed microgripper is capable of handling various sized micro-objects with a maximum jaw displacement of 134 μm and a high amplification ratio of 15.5.
70 citations
20 Feb 1989
TL;DR: In this article, a bimorph structure and an integrated heat source are described for electromechanical signal conversion, and the application of these transducers for microvalves, optical components, manipulators, and motors is discussed.
Abstract: Microactuators for electromechanical signal conversion are described. Basic elements of the transducer are a bimorph structure and an integrated heat source. Due to the differences of the coefficients of thermal expansion, a temperature-controlled deformation of the the bimorph structure occurs. Bulk and surface micromachining techniques can be used to achieve an object displacement perpendicular to or within the substrate plane. The main advantages of this class of actuators are simple fabrication processes and operation at standard IC (integrated circuit) voltage levels, allowing further system integration. The conversion characteristics are described, and the application of these transducers for microvalves, optical components, manipulators, and motors is discussed. >
69 citations