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Bio-inspired actuators play a crucial role in the design of wearable robots and exosuits, offering promising capabilities for achieving human-like movement and enhancing the functionality of robotic devices. This paper presents the development of a novel linear actuator utilizing a single wire of shape memory alloy (SMA) wound in a hexagonal pattern. The actuator features three segments of hexagonal bases aligned along a central axle and incorporates an antagonistic spring. Two of the hexagonal bases are fixed, enabling SMA winding, while the remaining base is movable, enabling output motion. Six pulleys are strategically positioned on the faces of these hexagonal blocks to wind the SMA wire between the fixed and movable parts. When heated, the SMA wire contracts, resulting in linear motion of the movable part along the axle (maximum stroke of 14 mm, and maximum load of 10 kgf). The displacement and force exerted by the actuator are adapted by adjusting the length of the SMA wire and the configuration of the output pulleys. Upon cooling, the movable part returns to its initial position through the restoring force of the antagonistic spring. Moreover, system identification and PID control techniques are employed to enhance the actuator's control performance. Experimental tests conducted in both open-loop and closed-loop controls validate the actuator's ability to successfully follow desired trajectories. The importance of this work lies in the novel hexagonal architecture, which offers a vital and practical solution to deal with the limitations related to size and strain of the SMA wire while leveraging the unique properties of SMA technology. [ABSTRACT FROM AUTHOR]

The primary purpose of the head servo in the track following tape drives is to track follow as accurately as possible during read/write operations in spite of disturbances such as tape edge movements or tape transients, internal and external vibrations transmitted to the head actuator and signal noise and dropouts. The track following and fine positioning is done using a position error signal (PES). Feedback controller design using proportional-integral-derivative (PID), lead-lag or estimator/controller techniques are used for maintaining accurate track following. This paper assumes that in addition to the PES signal, a head position signal is available for long seek, short seek, and track identification tasks, etc. In this paper, the development of a disturbance observer that supplements the nominal head servo controller in minimizing the effects of the tape transients is presented. The PES and the head position error signals are blended to provide a measure of the tape transient disturbance. This paper presents the theory of the disturbance observer and analyses to show the range of frequencies over which the disturbance observer will be effective. Finally, simulation results are presented for tape transients of various frequencies. [ABSTRACT FROM AUTHOR]

This paper presents a nonlinear model for the self-powered electromechanical actuator using radioactive thin films. The theoretical formulations are based on Hamilton principle and include the effects of geometric nonlinearity due to nonlinear curvature and load nonlinearity due to radioactive source. Two models which named as constant coefficient collector current model (CCM) and variable coefficient collector current model (VCM), respectively, are presented to formulate the electrostatic force. The nonlinear governing equations based on the CCM and VCM are solved using Galerkin principle and iterative method. The present nonlinear model is validated through direct comparisons with the experimental results in open literature. Numerical results show that the CCM is valid for small initial distance only whereas for large initial distance, the VCM must be used for accurate analysis. The effects of initial distance, cantilever beam length and thickness on the drop-down time of the self-powered electromechanical actuator are also discussed. [ABSTRACT FROM AUTHOR]

This paper presents a method of applying surface sputtering process in order to improve the displacement of an electrothermal V-shaped actuator (EVA) fabricated by the traditional SOI-MEMS technology. After sputtering, the measured resistance as well as resistivity of silicon EVA is approximately 1.55 times lower than non-sputtering. The displacements of both calculation and simulation in case of applying sputtering and non-sputtering were also compared. The results showed that the displacement of the sputtering V-shaped actuator is two times larger than non-sputtering at the same driving voltage of 16 V (both of calculation and simulation). The experimental results explained that the driving voltage of sputtering-specimen reduces about 40 and 48.4% at the same displacement (corresponding to 8 and 22 µm) in comparison with non-sputtering counterpart. [ABSTRACT FROM AUTHOR]

The article discusses the highlights of the 21st annual Information Storage and Processing Systems (ISPS) conference held by the American Society of Mechanical Engineers (ASME) in Santa Clara, California, on June 13 and 14, 2012. The conference provided papers on a variety of topics, including actuators, mechatronics and robotics. It presented contributions from countries around the world.

This paper proposes a new vacuum suction actuator mechanism that uses an elastic structure to increase vacuum efficiency. A typical problem in the vacuum suction system design might be the diversity of the target object topology, especially when applied for object handling tasks. When several objects must be lifted at once, the efficiency of suction operation could be deteriorated due to the incomplete attachment of suction pads. The situation might be worse when the target objects have uneven surfaces. A new mechanism has been proposed to solve these problems. The newly proposed vacuum suction actuator has passive compliance enabled with standard springs. This mechanism provides a higher enhancement in vacuum distribution, and the entire grasping mechanism successfully maintains the proper level of vacuum. The proposed method should be utilized in a portable vacuum suction-based grasping system with limited vacuum power. The theoretical vacuum efficiency was calculated, and a static simulation was performed. Experiments were conducted comparing the cases where this mechanism and the traditional check valve were used. [ABSTRACT FROM AUTHOR]

In this paper, we present modeling and control of a novel arc-shaped Shape Memory Alloy (SMA) actuator. The arc-shaped SMA actuator is developed to provide rotational motion with compliance for biologically inspired robots. We modeled the dynamics of proposed SMA actuator. Based on the dynamics structure, we have developed proportional integral derivative (PID), backstepping and integral backstepping controllers. We have tested experimentally these controllers with input, output and input-output combined disturbances. Based on tracking error, peak error, settling time and control effort, integral backstepping controller is the most suited controller for the actuator. [ABSTRACT FROM AUTHOR]

Macromodel for simulating static and dynamic behavior characteristic of MEMS has become a famous research focus. This review reports the progress on the recent development of macromodel of MEMS. The macromodel of MEMS is classed into numerical macromodel, analytical macromodel and macromodel in-system in this review. Numerical macromodel is the focus in this work and is discussed mainly from macromodel based on Galerkin method, macromodel based on trajectory piecewise-linear approach, macromodel based on proper orthogonal decomposition, macromodel based on Krylov subspace projection, macromodel based on mapping method, macromodel based on neural-network and so on. A variety of MEMS and microfluidic devices designed based on macromodel method are expounded and analyzed. This paper will provide an expedient and valuable reference to designers who research rapid simulation and optimal design of MEMS. [ABSTRACT FROM AUTHOR]

This paper presents the design and fabrication of the thermally actuated MEMS switches based on out-of-plane V-beams. The purpose of this research is to analyze the mechanical response of a V-thermal actuator fabricated from aluminum in order to improve the accuracy in response and to increase the switch lifetime. The actuation of this kind of switches is based on the thermal displacement of the mobile electrode under thermal load that is generated when the actuation voltage is applied. It can be used either as a capacitive switch or as a metal-to-metal one. The displacement of the mobile electrode for a given temperature is analytically calculated and validated both numerically and experimentally. Experimental investigations are performed on a macro-scale sample using a 3D digital image correlation measuring system, a heating source and a thermal camera for temperature monitoring. The first fabrication steps of the MEMS switch based on the V-beam thermal actuator are presented. The out-of-plane V-beams thermal MEMS switches can be monolithically integrated in RF applications. [ABSTRACT FROM AUTHOR]

Dynamic performance is one of the most critical factors in many MEMS products, such as micro accelerometers, vibratory gyroscopes, micro deformable mirror, etc. Essentially, the dynamic behavior is totally determined by two factors: the internal factor, the stiffness of structure and the external factor, the damping of environment. In this paper both factors are analyzed accurately and a theoretical dynamic model of parallel-plate actuators is presented. The stiffness of the structure, i.e. the spring constant k of the suspension beam that supports the moving plate of the actuator, is achieved by many accurate experimental tests. The damping of environment, referring to the squeeze film damping coefficient c in parallel-plate actuators, is analyzed by calculation and FEA simulation. Further, we consider c a linear function of the actuator displacement, but not a constant value. This treatment greatly improves the accuracy of the dynamic model and could be applied in parallel-plate actuators with large displacement. Dynamic behaviors of the actuators under squeeze film damping, such as natural frequency, response time and bandwidth, are predicted based on the model. Three kinds of parallel-plate actuators are designed and fabricated using a surface micromachining process to verify the estimation of the presented theoretical model and experimental test results have showed good consistency with the theoretical analysis. The dynamic model proposed in this paper could be broadly applied in the MEMS/NEMS systems. [ABSTRACT FROM AUTHOR]

A mechanics modeling is presented in this paper with focus given to understanding effect of flexible printed circuit cable's dynamic effect on tape head actuator's lateral motion in advanced, high capacity tape drives. The flexible printed circuit cable which connects the actuator to printed circuit board is first examined through establishment of analytical model to predict its profile with considerations of boundary conditions and mechanical design parameters. Secondly, equivalent stiffness produced by the flexible printed circuit cable when the linear tape head actuator is positioned along its lateral positions is examined. Finally, effect of tape head actuator's voice coil motor is studied and modeled as a magnetic suspension, contributing to stability and controllability of the actuator lateral motion dynamics. Validated by calibrated laboratory experiments, the work presented in this paper can add to the literature regarding dynamics and control of LTM in modern LTO drives. [ABSTRACT FROM AUTHOR]

In this paper, a novel electromagnetic micropositioner is designed from an orthogonal 3-P(4S) parallel mechanism through the substitution method and modular design techniques. Preliminary prototype experiments show that the micropositioner possesses an excellent decoupling performance. Thus an independent control strategy is carried out for the motion control of the micropositioner. An RBF neural networks based adaptive backstepping terminal sliding mode controller is designed according to the nonlinearity characteristics of the actuator. Parameters of the system are identified with a genetic algorithm. Finally, the performances of the micropositioner and the developed control strategy are verified. Experimental results demonstrate that satisfactory performances can be achieved. [ABSTRACT FROM AUTHOR]

Two-inertia systems are an important model in most industrial applications. It contains the actuator and load parts. For applications, such as position or velocity controls, due to coupling engagement, the discrepancy between the actuator and load is expected. Usually, this difference is unobservable. In this paper, we employ the hidden diffusion process to model the effects between the actuator and load, which is coupled by a flexible shaft. The hidden process is modeled by probability and has its expectation. Crucial theories are given for evaluation and verification. Based on the proposed methodology, four theoretical findings are given to show the effects of the hidden process in a two-inertia system. These results are useful for applications in which the actuator and load of an operation process, which reveals the hidden stochastic behaviors. [ABSTRACT FROM AUTHOR]

A novel laterally and micro-electro-thermally actuated RF MEMS switch is presented in this paper. Despite many RF MEMS switches requiring continuous actuation voltage to hold the switch at ON-state, the proposed switch remains ON without any DC power. The mechanical design of the switch is in such a way that, the contact force of the switch is in mN range with zero DC power consumption. The switch is modeled and its operation is comprehensively analyzed. The fabrication process is completely compatible with standard MetalMUMPs process. The switch requires actuation voltages of 0.5 and 0.9 V for U-shaped and V-shaped actuators, respectively. The switch is normally OFF with isolation of − 20 dB up to 100 GHz. The insertion loss of the switch at ON-state is better than − 0.1 dB up to 40 GHz and the return loss is below − 10 dB up to 100 GHz. The power consumption of the switch is confined to the transition time of the switch between OFF and ON states. Based on analytical and numerical simulations, the contact resistance of the switch is 0.028 Ω. The proposed switch in this paper is dedicated for applications in mobile front-ends especially antenna switch networks where the signal loss and power consumption are the main constraints. [ABSTRACT FROM AUTHOR]

In this paper, a linear actuator with a shape memory alloy (SMA) clamping mechanism for dual-slider positioning is proposed by using a single piezoelectric element (PZT). The linear actuator consists of an SMA clamping mechanism, a PZT, a permanent magnet, a steel plate, and a base with a guide way. The SMA clamping mechanism and the steel plate serve as a slider 1 and a slider 2, respectively. When the SMA clamping mechanism releases from the guide way, the slider 1 can be driven as an impact drive mechanism. On the other hand, when the SMA clamping mechanism clamps on the guide way, the slider 2 can be driven as a smooth impact drive mechanism. In the resting state, the SMA clamping mechanism clamps on the guide way to ensure the stability of the whole system. To investigate the performance of the SMA clamping mechanism and the linear actuator, a prototype was constructed with a compact size of 40 mm (L) × 15 mm (W) × 12 mm (H). Experimental results confirmed that the dual slides could be driven independently by clamping and releasing the SMA clamping mechanism. It was verified that both the sliders can achieve long motion ranges of several millimeters and high resolution of tens of nanometers. [ABSTRACT FROM AUTHOR]

This paper presents a new design and modeling of a novel variable stiffness scotch yoke series elastic actuator (VSY-SEA) mechanism that can achieve variable stiffness values with a linear relationship between torque and displacement. The main goal of this study was to design the yoke's shape in the scotch yoke mechanism for a system with the desired stiffness. The word "variable" in VSY-SEA does not simply mean that the system has different random stiffness, but rather that the system has the stiffness of the functional form desired by the designer. Yoke shapes in the scotch-yoke mechanism were designed by calculating the relationship between external torque and rotation angle of VSY-SEA, and the simulations were performed using CAD models with various yoke designs. A prototype of the model was built and the calculations were verified through experiments. [ABSTRACT FROM AUTHOR]

Pull-in instability continues to become increasingly important for the inertia switch owing the lower pull-in voltage. The model of double cantilever beam was used to reduce the pull-in voltage. Mathematical model of the pull-in voltage could be built to understand what influence the processing errors of structure parameters make on the stability of pull-in voltage. Based on this model verified by simulation, the control method could be put forward to improve the stability of pull-in voltage. With the help of LIGA technology and the measure system built based on the architect platform, the experimental results showed that the used control method was better, which had been validated by corresponding experiments. According to the established model, the pull-in voltage of different structures showed that the structure proposed in this paper had a lower pull-in voltage. [ABSTRACT FROM AUTHOR]

The parasitic motion principle was recently proposed to design piezo-driven actuators. Based on this principle, linear and rotary actuators with features of compact structure, large motion range, high velocity and high positioning resolution have been reported. However, some shortcomings such as the backward motion and the nonlinearity still exist and their causes are not clarified. To find potential reasons leading to these shortcomings, one stepping characteristic of a piezo-driven rotary actuator designed by the parasitic motion principle was investigated in this paper, and the correlation between the structure and one stepping characteristic was attempted to be established by theoretical analysis and simulations. Analysis results indicated that the nonlinearity in one stepping characteristic of the rotary actuator was correlated to the small gap between the inner and outer rings of the bearing as well as the self-deformation of the flexible gripper after the contact stiffness between the flexible gripper and the rotor reaches to the maximum value. The backward motion could be mainly resulted from the non-ideal driving wave. These analysis results enhance the understanding of the parasitic motion principle, which are meaningful for design and performance improvement of the parasitic motion principle linear or rotary actuators. [ABSTRACT FROM AUTHOR]

In this paper, we show the tracking performance of a rotary piezoelectric motor based hard disk drive actuator. The actuator is built and modeled for positioning servo in disk drive systems. The Piezo motor replaces the voice-coil-motor based primary actuation. Simulation and experimental results for its servo system proves that it can help to achieve track density of more than 1000 KTPI. [ABSTRACT FROM AUTHOR]

The purpose of this paper is based on micro fabrication technology, while integrating planar waveguide technology and the scattering phenomenon generated by electro-statically actuator thin film, to develop a 2-dimensional display technology capable of being cleared and re-displayed. For thin film displacement, the restoration of inward elasticity needs to be overcome. During thin film displacement, attraction due to suction occurs when coming into contact with light waveguide; electrostatic force and elastic force are restored and mutually balanced, causing display to light up. On the other hand, when input voltage is released, electrostatic force stops and thin film is restored to original position, causing display to darken. The design structure uses SU-8 as supporting posts, and PDMS as the electrostatic thin film suspended above the glass substrate (light waveguide). The experimental results show that a waveguide with an electrode length of 250 μm (sub-pixel length), a micro-post height of 27 μm, and a PDMS film thickness of 16 μm requires an actuator voltage of 314 V; and a micro-post height of 27 μm, and a PDMS film thickness of 8 μm requires an actuator voltage of 189 V. Thus, with an arrayed micro-electrode design, electronic paper and panels with large color display area could be manufactured. [ABSTRACT FROM AUTHOR]

Abstract  A high quality factor (Q-factor) piezoelectric lead zirconate titanate (PZT) thin film actuated single crystal silicon cantilever was proposed in this paper for resonant based ultra sensitive mass detection. Intrinsic energy dissipation and other negative effects from PZT-electrode stack were successfully compressed by separating the PZT actuator from the resonant structure. Excellent Q-factor, which is comparable to silicon cantilever (without actuator) and several times larger than that of latest reported other integrated cantilevers, was successfully obtained under both atmospheric pressure and reduced pressures. For a 30 μm-wide 100 μm-long cantilever, the Q-factor was measured as 1,113 and 7,279 under the pressure of 101.2 KPa and 35 Pa, respectively. Besides, it was found that greater Q-factor can be achieved at high vibration mode by the proposed structure. However, support loss became significant because of the increased actuator’s vibration amplitude which in turn leads to unexpected energy dissipation. Therefore, an optimized structure using node-point actuation was suggested and discussed in last section of this paper. [ABSTRACT FROM AUTHOR]

Abstract  This paper introduces a nodal analysis model for the out-of-plane beamshaped electrothermal microactuators. The electrothermal microactuator is traditionally simulated with finite element method (FEM) due to the complex coupling of the electrical, thermal and mechanical problem. This complex problem is classified into two parts in this paper: the coupling electrothermal problem and the coupling thermomechanical problem. By utilizing the characteristic of the temperature distribution, the nodal analysis model for the coupling electrothermal behavior of the electrothermal microactuator is built. The model scale is much smaller than the finite element model, which results in less computational consumption. Then the coupling thermomechanical behavior, such as the shift of the heat flow from the bottom of each part of the actuator to the substrate due to its out-of-plane movement, is modeled to make the model more reasonable. Many other effects which remarkably influence the behavior of the actuator are also taken into account. This model is verified by available experimental results, and achieves an agreement. [ABSTRACT FROM AUTHOR]

Microgrippers are commonly used for micromanipulation of micro-objects from 1 to 100 µm and attain features of reliable accuracy, low cost, wide jaw aperture and variable applied force. This paper aim is to review the design of different microgrippers which can manipulate and assemble µ-wire to PCB connectors. A review was conducted on microgrippers' technologies, comparing fundamental components of structure and actuators' types, which determined the most suitable design for the required micromanipulation task. Various microgrippers' design was explored to examine the suitability and the execution of requirements needed for successful micromanipulation. [ABSTRACT FROM AUTHOR]

This paper mentions a detail calculation of the equivalent dynamic parameters in differential equations of motion of the electrothermal V-shaped actuator. A heat transfer model for a thin beam (including the dependence of material properties on the temperature) is applied in order to solve more exactly temperature distribution and displacement of V-shaped beam system. Comparing the values of displacement in both calculation and simulation confirmed a higher accuracy of proposed equations. Moreover, a related formula between the minimum conversion stiffness and driving voltage amplitude is analyzed and examined to avoid the buckling phenomenon may occur in V-shaped beam system while working at a high voltage. [ABSTRACT FROM AUTHOR]

In this paper, piezoelectric principle based an actuator is design for a micropump, which is suitable for drug delivery systems. The natural frequency and stress analysis have been performed to determine the reliability of the device in terms of minimum safety factor. We have observed the uniform deflections of the actuators by varying the thicknesses of the piezoelectric layer of the actuator. The design of the actuators is considered in circular and rectangular geometry. The materials are selected appropriately such that the component is biocompatible and can be used in biomedical applications. Among the various considerations made on dimensions and geometry, it is observed that the circular piezoelectric actuator undergoes a high displacement of 2950 μm at an infinitesimal thickness of 0.1 μm. At minimum safety factor of one, the maximum stress and voltage the actuator can hold is 596 GPa and 8500 V respectively. [ABSTRACT FROM AUTHOR]

This paper describes an innovative miniature multi-port valve with a thin foil of shape memory alloy (SMA) as actuator for switching and dosing gaseous and liquid media. The normally closed (NC) microvalve has two structured SMA actuators that are switched independently of each other and either two inputs and one output or one input and two outputs. In addition to switching the media in the 3/4-way arrangement, it can also be used with a flow sensor in a closed loop control for dosing. Furthermore, the valve design is layer-based so that individual components can be manufactured according to given requirements or using different manufacturing technologies depending on the batch size. The SMA multi-port microvalve showed flow rates of about 2300 ml/min (nitrogen gas) and about 45 ml/min (water) for an applied pressure difference of 200 kPa and a heating current of about 400 mA. For flow regulation a closed loop control was realized and evaluated for a pressure difference of 100 kPa and a setpoint value of 900 ml/min. [ABSTRACT FROM AUTHOR]

Abstract  This paper concerns the modeling of a piezoelectric micro-scanner. The micro-scanner presented in this paper uses multimorph-type bending actuators to tilt a square plate mirror. A complete analytical model of the piezoelectric micro-scanner is presented. Each step of the modeling has been validated by Finite Element Modeling. This theoretical model based on strength of material equations calculates the force generated by the multimorphs on the mirror, the profile of the structure and the angular deflection of the mirror. The proposed model, used to optimize the design of the piezoelectric silicon micro-scanner, is intended for further HDL integration, thereby allowing rapid system level simulation and optimization. [ABSTRACT FROM AUTHOR]

Extensive researches are being conducted to develop miniaturized pumping systems to fulfill the need for accurate delivery of fluids at required rates, particularly in the biomedical field. This paper presents the design, fabrication, and testing of novel valveless micropump actuated through an amplified piezo actuator. The proposed model of the micropump pump has the unique feature of a disposable chamber and employs low-cost polymeric materials, conventional molding and machining operations for fabrication. The disposable part of the pump consists of a laser-cut pump chamber with nozzle/diffuser made of Polymethyl methacrylate (PMMA) and conventionally molded silicone rubber diaphragm. The retrofit part includes the amplified piezo actuator and support structures build from PMMA. Systematic characterization of the pump was carried with water and blood mimicking fluid to understand the effect of operating parameters such as driving frequency and actuation voltage on flow rate and back pressure of the micropump. Experimental results show that the proposed design was capable of pumping 3.3–3.4 ml/min of dye solution and 1.7–1.75 ml/min of blood mimicking fluid at a driving frequency of 5 Hz and actuation voltage of 150 V. The corresponding computed volume resolution/stroke of the pump was found to about 5.75 µl and 11.25 µl of blood mimicking fluid and dye solution, respectively. The proposed pump was found to work effectively against a maximum back pressure of 156 Pa with blood mimicking fluid and 250 Pa with the dye solution as the working fluid under the same operating condition of 5 Hz and 150 V. [ABSTRACT FROM AUTHOR]

In two past decades, there are so many works representing to elastic behaviors of cantilever MEMS actuators in the micro and nanoscales for various loading conditions and geometries. However, there are little efforts available for the permanent plastic behavior of the MEMS structures and actuators. In addition, the most size—dependent plasticity considerations based on gradient models have been limited to primary concepts on material modeling or microstructural evolution as compared with structural analyses. In this paper, a conventional mechanism-based strain gradient (CMSG) plasticity theory is applied to investigate permanent behavior of the cantilever micro-beam actuators, by determining the effect of length scale on flexural displacement. If the beam is scaled to micron size, mechanical behavior follows from material dimension or length scale. While the model consisted of a multiple plastic work hardening, its kinematics is established on the Euler–Bernoulli hypothesis. The deflection of cantilever MEMS actuator is determined for different cases of the loading and length scales, compared with other relevant theoretical and experimental observations. Also, the effect of the elastic medium of the environmental foundation is considered for the actuator, dedicatedly. [ABSTRACT FROM AUTHOR]

This paper designed a micro planar induction heater for thermal bubbles generation. The micro heater which consists of a micro planar coil, a copper heating plate and a glass slide was fabricated with MEMS fabrication process. The relations between the heating performance and the thickness of heating plate were studied in the simulation with the software of COMSOL. The experimental system has been built and the experimental tests for thermal bubble generation have been also carried out with the prototype. The process of thermal bubbles generation was recorded by the video camera. The frequency of AC current applied in the experiment is 100 kHz and the heating time of 1 s. The experimental results indicated that the micro heater has the best heating performance with the heating plate thickness of 12-16 μm, and the minimum power for thermal bubbles generation was only 0.427 W. This micro heater can be applied to a variety of thermal bubble devices, such as micro actuator, micro ejector and micro pump. [ABSTRACT FROM AUTHOR]

Designing a comb-actuator requires calculating electrostatic force. In this paper, the analytical and high accurate formula of electrostatic force for comb-actuators with ground substrate is derived. This analytical formula enables the fringe effect to be taken into account. According to the geometric feature, the whole structure of a comb-actuator is divided into two types of units, the capacitances of which can be calculated by Schwarz-Christoffel mapping. Based on the capacitance results, the electrostatic force acting on moving fingers can be obtained by the energy method. The results of electrostatic force obtained by this analytical formula are compared with that obtained by finite element method. The compared results illustrate that the analytical formula has very high accuracy for calculating electrostatic force, which is meaningful for designing comb-actuator precisely. [ABSTRACT FROM AUTHOR]

We develop a rotary motor to reduce backward motion in stick–slip with an active clamp mechanism. Backward motion refers to the undesired movement observed when operating a rotary stick–slip motor powered by a piezoelectric actuator under actual conditions, where the rotor rotates in the opposite direction to the intended rotation. This could cause imprecision and inaccurate motion. The conventional stick–slip motor relies on contact with the rotor to induce rotation. The proposed active clamp mechanism adjusts the contact distance with the rotor, ensuring contact is maintained only when the rotor is rotating. This helps reduce backward motion. Additionally, implementing this mechanism using the conventional method requires one stick–slip module for rotation and two inchworm drive modules for clamping. In contrast, the proposed mechanism consists of a single module each for the driving actuator and clamping actuator. A preliminary model with a dimension of 34 × 27 mm was constructed for experimentation. Through the experiments, it was confirmed that the proportion of backward motion relative to the initial movement in one step decreased by approximately 20%. Furthermore, with the reduction in backward motion, the rotational displacement per step was confirmed to improve by about twice, increasing from 17 to 33 millidegrees. [ABSTRACT FROM AUTHOR]

This paper presents design and analysis of microelectromechanical system (MEMS) based displacement amplification mechanism actuated using thermal actuators with enhanced performance. The proposed model consists of chevron shaped thermal actuators, an amplification mechanism capable of amplifying displacement 20 times and an electrostatic comb drives for sensing displacements. When voltage is applied to thermal chevrons, displacement is produced which is then amplified 20 times. Steady state static thermal electrical analysis is performed under variable resistivity and voltage bias of 2 V. In-plane reaction forces of magnitude 194.2 and 150.91 µN along X and Y-axis, respectively, thus producing displacement of 0.11 and 2.22 µm along X and Y-axis, respectively. Time domain simulations of device are carried with constant electrical resistivity, variable voltage and convective boundary conditions. Modal analysis of the mechanism is carried out to predict the natural frequencies and associated mode shapes of mechanism during free vibrations. The desired mode is at frequency of 286.160 kHz. Dynamic simulations including direct integration-transient, transient modal and steady state modal analysis are performed on the device for time span of 0.0006 s, under application of 25 g and frequency range of 200-300 kHz. Simulation results prove the viability of the mechanism as an amplification device with enhanced voltage-stroke ratio. [ABSTRACT FROM AUTHOR]

In this paper, a compact synthetic jet actuator comprising a primary jet actuator and a synthetic jet chamber was proposed. This synthetic jet actuator can enhance the total airflow rate by combining the primary, and secondary flows synthesized by the synthetic jet. The oscillating diaphragm and valve parts of the synthetic jet actuator were designed as a closed magnetic flux loop to enhance the magnetic flux density in the coils. The primary jet actuator was designed with a separate inlet and outlet to serve as a heat-dissipation application and prevent the re-ingesting of heated air. Thus, a dynamic model of a synthetic jet actuator was constructed, and motion equations were subsequently derived using plate theory, the Lorentz law, and magnetic flux simulation. The behavior in association with the displacement of the oscillating diaphragm, oscillation frequency, and driving current is discussed in this paper. Finally, an experimental rig was constructed to verify the correctness of the airflow simulations. The synthetic jet actuator was integrated with flow channels, and achieved an airflow rate of 9.23 L/min at a 1.5 V driving voltage. [ABSTRACT FROM AUTHOR]

In this paper, we have developed a fabrication process for micro synthetic jet actuators (SJA) by bonding a high-quality Pb (Zr,Ti) O (PZT) ceramic wafer to a silicon wafer using epoxy resin at low temperature (<150 °C). The bulk-PZT was lapped and polished to be PZT thick film by chemical mechanical polishing (CMP) method, and patterned by wet-etching method. The cavity and orifice of SJA were formed by inductive coupled plasma etching (ICP) method. A MEMS piezoelectric SJA was then completed and characterized, including the performance of the PZT thick film. While the dimension of bonded PZT thick film is about 6,000 × 6,000 × 100 μm, and the dimension of Si membrane is about 1,000 × 1,000 × 20 μm. The experimental results show that the maximum center amplitude of PZT-Si diaphragm is 15.05 μm at Vp-p of 90 V and the resonant frequency of 5 kHz, and the maximum jet velocity is higher than 11 m/s. This novel process has great potential to fabricate MEMS piezoelectric synthetic jet actuators. [ABSTRACT FROM AUTHOR]

Piezoelectric vibration energy harvesters as an autonomous power source for various types of sensors, actuators and MEMS devices have attracted increasing attention in recent years. Traditional MEMS-based PZT single beam vibration energy harvester has low voltage output (usually <1 V) which causes rectifier circuit to consume most of power or turn off in practical applications. In this paper, in order to improve the voltage output of MEMS-based PZT vibration energy harvester as well as ensure high power output, a PZT beam array configuration for MEMS-based vibration energy harvester is proposed. Based on Hamilton's principle and Euler-Bernoulli beam theory, mathematical model for the proposed vibration energy harvester is established. Two different dimensions MEMS-based PZT beam array vibration energy harvesters are designed and fabricated through micro-fabrication techniques. The performances of the two types of fabricated vibration energy harvesters are characterized and compared with traditional vibration energy harvester in experiment. Experimental results agree well with theoretical analysis, and the experimental results show that the better performance fabricated vibration energy harvester can generate 121.4 μW and 3.5 V respectively at 1 g acceleration. [ABSTRACT FROM AUTHOR]

A new lateral electro-thermally actuated latching RF MEMS switch is presented in this paper. In contrast to conventional electrostatic or electro-thermal MEMS switches which require an actuation voltage to hold the switch in on or off state, this switch has a true mechanical latching design in such a way that there is no power required to hold the switch on or off. The switch structure only consumes power while transition between states. In order to satisfy low voltage operation, electro-thermal actuators are chose as the drive and latching actuators of the switch. The required actuation voltage for drive and latching actuators is 6 V. The switch consumes a power of <99 mW while transition from off to on state and also consumes a power of 46 mW for 0.3 ms in transition from off to on states. FEM simulations show that the return loss of the switch is below −10 dB up to 140 GHz and is below −20 dB up to 40 GHz. The insertion loss of the switch is less than −1 dB up to 150 GHz. The switch isolation when it is off is below −20 dB up to 160 GHz. The switch has potential applications in low voltage, low power and high performance RF tuning and switching applications. [ABSTRACT FROM AUTHOR]

In this paper, a novel concept of a thermo-mechanical MEMS actuator using aluminum thin-film heaters on a thermal oxide for electrical insulation is presented. The actuator is part of an universal tensile testing platform for thermo-mechanical material characterization of one dimensional materials on a micro- and nano-scopic scale under different environmental conditions, as varying temperatures, pressure, moisture or even vacuum and is realised in BDRIE technology. It is shown, that the actuator concept fulfills the requirements for the use in a tensile loading stage along with heterogeneously integrated nanofunctional elements, following a specimen centered approach in line with bottom-up self-assembly processes. Simulation and experiment agree very well in the thermal and mechanical domain and allow subsequent optimisation of the actuator performance. [ABSTRACT FROM AUTHOR]

This paper reports a study on wireless radiofrequency (RF) power transfer to and heat generation in micropatterned coils for wireless control of thermally-driven microdevices. Inductor-capacitor circuits with the planar spiral coils act as RF receivers as well as frequency-sensitive wireless heaters that selectively produce heat when resonated with external RF magnetic fields. Electrical and thermal characterizations are performed using two sets of microfabricated circuits with varying numbers of turns and fill ratios defined in the spiral coils. The measurements in electrical parameters of the circuits, coupling coefficient, power transfer efficiency, and heat generation have been evaluated and parameters show good consistency between them. These tests reveal maximum power transfer efficiency and steady-state temperature of ~35 and 99 °C, respectively, for the coil with a fill ratio of 0.55. The reported results will serve as a basis for the design of the wireless heater, which provide a promising path to radio-control of thermoresponsive actuators such as shape-memory alloys and hydrogels. [ABSTRACT FROM AUTHOR]

This paper reports a novel design for electrostatic microgrippers. The new structure utilizes rotary comb actuators to solve the pull-in problem of microgrippers during large displacement manipulation and therefore avoids the widely used conversion systems which necessitate a high driving voltage. The gripper is fabricated using a SOI process with a 60 μm structural layer. Test results show the gripper obtained a displacement of 94 μm with an applied voltage of 100 V. An animal hair is gripped to demonstrate the applicability of the gripper for micro object manipulations. [ABSTRACT FROM AUTHOR]

Curved electrode actuators displace on the order of a biological cell diameter at low actuation voltages, making them a potential candidate for probing and micromanipulation of cells in an underwater, closed microenvironment. Here, a closed microenvironment is formed by bonding a Polydimethylsiloxane-based cap-like structure to the actuator; however, the presence of Au/Cr conductive layers on the actuator reduce the available silicon surface area of the actuator—resulting in poor adhesion. Therefore, we propose to fabricate the actuators without these conductive layers. In this paper, we demonstrate the absence of these layers has a minimal effect on the actuator’s peak-to-peak displacement and force. The actuator achieves the following performance metrics: large displacement (1-10 μm) and force (1-21.5 μN) range; broad frequency range (1-500 Hz); and low actuation voltages (0-8 V) in viscous media that are necessary for cell probing and micromanipulation applications. [ABSTRACT FROM AUTHOR]

Comb drive actuators are very important microelectromechanical systems structures that are widely used in many applications. They are currently used in force balanced accelerometers, resonant accelerometers and resonant gyroscopes, micro-grippers and micro-engines. In addition, they are extensively used in opto-mechanical subsystems such as switches and variable optical attenuators. The goal of this paper is to present a comb drive actuator model design with ultra-low pull-in voltage to achieve large displacement, deriving the exerted forces equations, mechanical analysis and the most important problems, also comparing with the previous work done to treat these problems. [ABSTRACT FROM AUTHOR]

Design, fabrication and characterization of a novel RF switch is proposed in this paper. The multiport RF MEMS switch provides a single input multiple output novel topology suitable for satellite payload applications. A single ETA is used to switch the device from one mode to another. When a voltage difference is applied across the electrode pads of ETA, and depending on the configuration, the actuator actuates forward or backward in plane producing either a quad or dual output respectively. The reflection loss and insertion loss are improved effectively. Measurement results show that in `dual mode’ position, the input reflection coefficient (S11) is less than − 50 dB with the forward transmission coefficient (S21) better than − 2 dB at 0-15 GHz. At ‘quad mode’, position, the input reflection coefficient (S11) is less than − 55 dB with the forward transmission coefficient (S21) better than − 4 dB at 0-15 GHz. The larger than 50 dB over 0-15 GHz isolation realized in both modes of operation ensures dual and quad mode outputs without information loss. The actuation voltage is reduced to 4.5 V. The measured power handling capability can reach up to 35 dBm while the power consumption of the switch is 50 mW. This compact RF MEMS capacitive switch possesses excellent performances in terms of low insertion loss, high isolation, low power and high power handling capability. [ABSTRACT FROM AUTHOR]

In this paper, comprehensive numerical studies are performed to investigate the effects of the geometrical factors on the performance of the low-pressure gas actuator. The flow feature and force generation mechanism inside a rectangular enclosure with heat and cold arms as the non-isothermal walls are inclusively discussed. Also, comprehensive parametric studies are done to reveal the effects of physical parameters on the performance and characteristics of this device in different operating conditions. In this study, the Knudsen number is varied from 0.1 to 4.5 to investigate all characteristics of the thermal-driven force inside the MEMS sensor. In order to simulate a rarefied gas inside the micro gas detector, Boltzmann equations are applied to obtain high precision results. To solve these equations, Direct Simulation Monte Carlo approach is used as a robust method for the non-equilibrium flow field. The effects of length, thickness and length ratio of arms are comprehensively investigated in different ambient pressures. Our findings show that maximum force increases approximately 3.66 times when the length of the arms is increased from 50 to 150 µm. In addition, the obtained results demonstrate that the geometrical parameters of arm induce complex structure in rarefied pressure, and the mechanism of force generation highly varies in the different pressure conditions. [ABSTRACT FROM AUTHOR]

This study investigates the scale effect on nonlinear behavior of a clamped–clamped circular graphene sheet nanoplate actuator, which is electrostatically actuated by various vdW forces, tensile loads, and hydrostatic pressures. The circular nanoplate model is developed by using Eringen’s nonlocal elasticity theory. The nonlinear behavior of the circular nanoplate actuator subject to nonlocal effect, electrostatic vdW forces, tensile loads, and hydrostatic pressures, is then carefully derived, analyzed and presented. A proposed hybrid differential transformation/finite difference method is first introduced to characterize the influence of scale effect on nonlinear behavior of the circular nanoplate subject to DC loads. The modeling result shows that the pull-in voltage deviates less than 2.71% as compared to that appeared in the literature obtained by using a different approach. The validity of the proposed hybrid method is thus verified and can thus be employed to further characterize the effect of small scale for different electrostatic actuation of tensile loads and hydrostatic pressures in greater details. The structural modeling results indicate that the pull-in voltage increases obviously with increasing scale effects. Overall, the results also reveal that the hybrid method presented in this paper is effective and can be used to accurately quantify the pull-in voltage in circular nanoplate systems under different associated actuation. [ABSTRACT FROM AUTHOR]

In this paper, a smooth impact drive mechanism (SIDM) actuation method for flapping wing mechanism which can be used in bio-inspired micro air vehicles is proposed. The SIDM-actuated flapping wing mechanism is composed of a base, a linear actuator, and a dual slider-crank mechanism. Based on the driving principle of SIDM, the linear actuator can generate a reciprocating linear motion with a long travel range. Via the dual slider-crank mechanism, the reciprocating linear motion can be converted to a flapping motion with a relatively high frequency. In addition, due to no gearbox used in the design, the SIDM-actuated flapping wing mechanism can be made with small volume and light weight. [ABSTRACT FROM AUTHOR]

A 30 V switching circuit with standard CMOS foundry-made transistors on a silicon-on-insulator (SOI) wafer is proposed.The key fabrication process is mesa isolation postprocessing that physically separates a series-connected transistor's body so that we can apply independent substrate (body) voltages to each transistor. The process is a combination of anisotropic and isotropic deep reactive ion etching (DRIE) with a single mask. In the experiment, CMOS transistors were fabricated on a 9-µm-thick 6-in. SOI wafer in an LSI foundry company, and the postprocess was carried out in a MEMS cleanroom. In this paper, full integration with gate-voltage-level shift circuits and dynamic driving of an electrostatic comb-drive MEMS device with series-connected transistors are presented. [ABSTRACT FROM AUTHOR]

In this paper, we improve and develop a micro cam system, in which reciprocating linear movement of two electrostatic linear comb-drive actuators (ELCA) is transformed into the unilateral rotation of a cam rim through six elastic wings of motion-transmission mechanisms. The system was fabricated by using SOI-MEMS technology and only one photo mask. Our experimental results show that the new micro cam system runs stably while the driving frequency ranging from 1 to 30 Hz with the driving voltage V = 100 V. In addition, the average angular velocities of the cam rim matched with the theoretical results better than the velocities measured in the previous micro cam system. [ABSTRACT FROM AUTHOR]

Dual stage actuators have recently been implemented in hard disk drive suspensions in order to increase the track density of hard disk drives. This paper investigates the lateral deflection (lateral stroke), stress distribution and design characteristics of a suspension-based and a collocated flexure-based dual stage actuated suspension design using finite element analysis. Design parameters for each suspension design are examined and guidelines for improved lateral deflection characteristics are proposed. [ABSTRACT FROM AUTHOR]

A design and implementation of a dual step position align stage for digital exposure process and analytical analysis of the presented hardware architecture are introduced in this paper. A mobile plate of the proposed dual step position align stage is connected to its base with four independent dual degree of freedom (DOF) decoupled actuator assembly. The dual DOF decoupled actuator assembly is driven with a brushless DC motor, two pneumatic locking devices, and four kinematic mechanisms. Thanks to the dual degree of freedom independent actuation unit combined with pneumatic locking device, the proposed mechanism provides fully decoupled vertical and horizontal motions. The design specification for the operational accuracy and the repeatability are determined by the primitive digital pattern generation scheme based upon a point array method. A kinematic formulation using a geometric approach is provided for the proposed dual step position align mechanism. In addition a numerical simulation for the mechanism is also carried out and a series of system testing is followed. [ABSTRACT FROM AUTHOR]