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Terahertz MEMS metamaterials
Published in Guangya Zhou, Chengkuo Lee, Optical MEMS, Nanophotonics, and Their Applications, 2017
Prakash Pitchappa, Chengkuo Lee
An electrostatic comb drive is one of the most popular MEMS actuators for achieving in-plane reconfiguration. A comb drive actuator consists of a pair of interdigitated comb finger sets, where one set is fixed to the substrate, and the other is suspended and made movable. Upon applying a voltage between these two sets of comb fingers, an electrostatic force is generated that will displace the suspended set of comb fingers in the lateral direction. When the voltage is removed, the movable comb finger set will return to the original position. Usually, for the electrostatically-driven in-plane MRMs, the movable part of the metamaterial is housed in a suspended frame which is attached to a comb drive actuator on either side. This allows for both positive and negative in-plane deformation from the initial rest position and this also doubles the displacement range.
Microdynamic Systems in the Silicon Age
Published in Bharat Bhushan, Handbook of Micro/Nano Tribology, 2020
The comb drive has become a very frequently used microactuator both for resonant and nonresonant systems. Because the actuated part is a flexing structure, there is no surface friction in its motion, and it can be driven in resonance with a very high mechanical Q value (100,000 in vacuum). Much work is continuing on comb-drive resonators and their applications and they have been made by substrate as well as by surface micromachining. Figure 13.4 compares aspects of the behavior of the comb-drive to that of a parallel-plate actuator. A photograph of one of the original moving comb structures undergoing oscillation is shown in Figure 13.5.
Reliability modeling for multi-component system subject to dependent competing failure processes with phase-type distribution considering multiple shock sources
Published in Quality Engineering, 2023
Hao Lyu, Shuai Wang, Zaiyou Yang, Hongchen Qu, Li Ma
We use a micro-engine in micro-electro-mechanical system (MEMS) as an illustration. The micro-engine includes comb-drive actuators and a rotating gear. The linear displacement of the comb-drive is transformed into the circular motion of the gear via the pin joint by applying voltage. Therefore, the wear process of the contact surface between the cylindrical pin and the rotating gear can be regarded as a soft failure process. In addition, the system will be affected by shocks, and a large enough shock will lead to spring fracture; this is a hard failure process (Tanner et al. 2000). At the same time, the micro-engine will be affected by vibration, which will not affect the spring but may cause adhesion between the combs, resulting in an electric short. Therefore, it is significant to classify the shock set of each component to establish the reliability model of a multi-component system experiencing DCFP.
Mechanical testing of two-dimensional materials: a brief review
Published in International Journal of Smart and Nano Materials, 2020
Karrar K. Al-Quraishi, Qing He, Wesley Kauppila, Min Wang, Yingchao Yang
One of the most common micromechanical devices has been developed by Espinosa et al. [177]. There are two types of actuators: one is a thermal actuator and the other is an electrostatic (comb drive) actuator. The thermally driven microelectromechanical systems (MEMS) platform shown in Figure 14(a) includes an on-chip actuator, an electronic load sensor, and a gap for placement of nanostructures [172,177]. A major advance in this design is the introduction of a capacitance load sensor that measures displacement electronically, based on differential capacitive sensing rather than microscope imaging. The MEMS platforms are good for the in situ SEM and TEM tensile tests. The thermally actuated micromechanical device has the capability of testing stiffer structures, such as films and nanowires with larger diameters. In addition, the comb-driven micromechanical device is suitable for compliant structures, such as CNTs and nanowires with smaller diameters. In fact, many MEMS platforms based on this configuration have been designed and developed, including the one demonstrated in Figure 14(b) [173,178–181].
Design and kinetostatic modeling of a compliant gripper for grasp and autonomous release of objects
Published in Advanced Robotics, 2018
Tien-Hoang Ngo, Hong-Van Tran, Thang-An Nguyen, Thanh-Phong Dao, Dung-An Wang
Demaghsi et al. [37] incorporated an electrostatic comb drive into their microgripper design, where a chevron type electrothermal actuator was used to grip objects. By actuating the additional comb drive, the adhesion between the target particle and the end effector was decreased by vibrating the end effectors. In our gripper design, the end effectors are driven by the BM. The impact pestle is an integral part of the BM. The source of vibration is induced by the motion of the BM. No additional actuation means is required. The characteristics of the bistability and snap through behavior of the BM are exploited to achieve the autonomous release operation of the gripper. The fact that no power is required to keep the BM in either of its stable equilibrium positions can reduce the power consumption dramatically [38].