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: In this article, a shape memory alloy (SMA) thin film was constructed for a gripper made of SU-8 thick photoresist. But the performance of the gripper was limited to a force of 50 mN, corresponding to 400 μm of opening amplitude.
Abstract: In this paper, we present the fabrication process of a shape memory alloy (SMA) thin film in both monolithic and hybrid configurations. This provides an effective actuation part for a gripper made of SU-8 thick photoresist. We also extensively describe and discuss the assembly of the SMA thin film with the SU-8 mechanism. Measurements show that the SU-8 gripper is able to achieve an opening action of 500 μm in amplitude at a frequency of 1 Hz. Finite element model simulations indicate that a force of 50 mN, corresponding to 400 μm of opening amplitude, should be produced by the SMA actuator. Although the assembly of the TiNi SMA thin film with the SU-8 mechanism is demonstrated, the bond reliability needs further development in order to improve the thermal behavior of the interface. In this paper, we show that SU-8 is well suited as a structural material for microelectromechanical systems (MEMS) applications. An attractive feature in the MEMS design is that the SMA generated force is well matched with the elastic properties of SU-8. From the application point of view, a SMA-actuated SU-8 high-aspect-ratio microgripper can serve as a secure means to transport microelectronics device, because it provides good grasping and safe insulation. This is also a preliminary result for the future development of biogrippers.
168 citations
TL;DR: In this paper, the analysis, design, and characterization of a superelastic alloy (NiTi) microgripper with integrated electromagnetic actuators and piezoelectric force sensors is presented.
Abstract: This paper presents the analysis, design, and characterization of a superelastic alloy (NiTi) microgripper with integrated electromagnetic actuators and piezoelectric force sensors. The microgripper, fabricated by electro-discharge machining, features force sensing capability, large force output, and large displacements to accommodate objects of various sizes. The design parameters for the embedded electromagnetic actuators were selected on the basis of finite element sensitivity analysis. In order to make the microgripper capable of resolving gripping forces, piezoelectric force sensors were fabricated and integrated into the microgripper. The performance of the microgripper, the integrated force sensors, and the electromagnetic actuators was experimentally evaluated. A satisfactory match between experimental results and finite element simulations was obtained. Furthermore, comparison studies demonstrated that the superelastic alloy (NiTi) microgripper was capable of producing larger displacement than a stainless steel microgripper. Finally, experimental results of optical fiber alignment and the manipulation of tiny biological tissues with the superelastic microgripper were presented.
163 citations
01 Jan 1999
TL;DR: In this article, the authors describe in-plane microactuators fabricated by standard microsensor materials and processes that can generate forces up to about a milli-newton.
Abstract: This paper describes in-plane microactuators fabricated by standard microsensor materials and processes that can generate forces up to about a milli-newton. They operate by leveraging the deformations produced by localized thermal stresses. Analytical and finite element models of device performance are presented along with measured results of fabricated devices using electroplated Ni, LPCVD polysilicon, and p/sup ++/ Si as structural materials. A maskless process extension for incorporating thermal and electrical isolation is outlined. Test results show that static displacements of /spl ap/10 /spl mu/m can be achieved with power dissipation of /spl ap/100 mW, and output forces >300 /spl mu/N can be achieved with input power <250 mW. It is also shown that cascaded devices offer a 4/spl times/ improvement in displacement. The displacements are rectilinear, and the output forces generated are 10/spl times/-100/spl times/ higher than those available from other comparable options. This performance is achieved at much lower drive voltages than necessary for electrostatic actuation, indicating that bent-beam thermal actuators are suitable for integration in a variety of microsystems.
153 citations
TL;DR: VBFM has the potential to increase the robustness and reliability of micromanipulation and biomanipulation tasks where force sensing is essential for success and is demonstrated for both a microcantilever beam and a microgripper.
Abstract: This paper demonstrates a method to visually measure the force distribution applied to a linearly elastic object using the contour data in an image. The force measurement is accomplished by making use of the result from linear elasticity that the displacement field of the contour of a linearly elastic object is sufficient to completely recover the force distribution applied to the object. This result leads naturally to a deformable template matching approach where the template is deformed according to the governing equations of linear elasticity. An energy minimization method is used to match the template to the contour data in the image. This technique of visually measuring forces we refer to as vision-based force measurement (VBFM). VBFM has the potential to increase the robustness and reliability of micromanipulation and biomanipulation tasks where force sensing is essential for success. The effectiveness of VBFM is demonstrated for both a microcantilever beam and a microgripper. A sensor resolution of less than +/-3 nN for the microcantilever and +/-3 mN for the microgripper was achieved using VBFM. Performance optimizations for the energy minimization problem are also discussed that make this algorithm feasible for real-time applications.
153 citations
01 Jan 1999
TL;DR: In this article, the authors describe in-plane microactuators fabricated by standard microsensor materials and processes that can generate forces up to about a milli-newton.
Abstract: This paper describes in-plane microactuators fabricated by standard microsensor materials and processes that can generate forces upto about a milli-newton. They operate by leveraging the deformations produce by localized thermal stresses. Analytical and finite element models of device performance are presented along with measured results of fabricated devices using electroplated Ni, LPCVD polysilicon, and p++ Si as structural materials. A maskless process extension for incorporating thermal and electrical isolation is outlined. Test results show that static displacements of =lo pm can be achieved with power dissipation of =lo0 mW, and output forces >300 pN can be achieved with input power <250 mW. It is also shown that cascaded devices offer a 4X improvement in displacement. The displacements are rectilinear, and the output forces generated are lox-1OOX higher than those available from other comparable options. This performance is achieved at much lower drive voltages than necessary for electrostatic actuation, indicating that bentbeam thermal actuators are suitable for integration in a variety of microsystems.
153 citations