Simulation of shaped comb drive as a stepped actuator for microtweezers application

Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba, Canada
Sensors and Actuators A Physical (Impact Factor: 1.9). 09/2005; 123-124:540-546. DOI: 10.1016/j.sna.2005.03.031


Finite element analysis is used to simulate electrostatic actuated, shaped comb drives operating under dc conditions (zero actuating frequency). A dynamic multiphysics model is developed using the arbitrary Lagrangian–Eulerian (ALE) formulation. Results show the coupled interaction between the electrostatic and mechanical domains of the transducer. The analysis is based on the evolution of electrostatic force versus comb finger engagement. The relationship between incremental lateral displacement and actuation voltage illustrates the potential for stepped movement for a shaped comb drive. Additionally, through numerical simulations, this project determines an optimum design for a dc-actuated comb drive, which has controllable force output and stable engaging movement.

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    • "Strategies to increase the force density include increasing the number of comb fingers, increasing the electrical potential, and reducing the gap between the fixed and moving electrodes. However, each of these strategies has their own drawbacks: increasing number of comb fingers results in an increase in active area, increasing the potential corresponds to an increase in driving voltage, and reducing the gap width has a limitation in terms of fabrication capability [18, 19]. Therefore, it is difficult to fabricate electrodes beyond a minimum size and correspondingly small gap (2-3 μm). "
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    ABSTRACT: This paper presents the design and evaluation of a high force density fishbone shaped electrostatic comb drive actuator. This comb drive actuator has a branched structure similar to a fishbone, which is intended to increase the capacitance of the electrodes and hence increase the electrostatic actuation force. Two-dimensional finite element analysis was used to simulate the motion of the fishbone shaped electrostatic comb drive actuator and compared against the performance of a straight sided electrostatic comb drive actuator. Performances of both designs are evaluated by comparison of displacement and electrostatic force. For both cases, the active area and the minimum gap distance between the two electrodes were constant. An active area of 800 × 300 μ m, which contained 16 fingers of fishbone shaped actuators and 40 fingers of straight sided actuators, respectively, was used. Through simulation, improvement of drive force of the fishbone shaped electrostatic comb driver is approximately 485% higher than conventional electrostatic comb driver. These results indicate that the fishbone actuator design provides good potential for applications as high force density electrostatic microactuator in MEMS systems.
    Full-text · Article · Jul 2014
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    • "We horizontally displace one of the combs a small amount x i+1 − x i by using the arbitrary Lagrangian–Eulerian moving boundary technique [19]. Then we compute the new capacitance C FEA,i+1 . "
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    ABSTRACT: We present some of the design, modeling, and simulation features of a computer-aided engineering tool for microelectromechanical systems (MEMS) called SUGAR. The features include a flexible SPICE-like netlist language for MEMS design, a simple modeling framework for computationally efficient lumped models, an extensible architecture to which users can add features, and the ability to display 3-D circuits together with deflected electromechanical structures. Since SUGAR is programmed in MATLAB, many MATLAB functions and toolboxes may be used with SUGAR. Such attributes facilitate the exploration of design spaces and feature modifications. In this paper, we describe SUGAR's extensible architecture, flexible design methodology, modeling framework, and reduced-order modeling technique. We do not present the many other advances made for SUGAR by other developers. For a test case, we choose an advanced microdevice that is difficult to simulate with conventional MEMS software. We show that the relative errors of our lumped models are less than 3% of the finite-element analysis (FEA), that the computational costs are less than 1% of the FEA, and that simulation of the test case fairly agrees with the experiment.
    Full-text · Article · Jan 2008 · Journal of Microelectromechanical Systems
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