Electrode configuration method with surface profile effect in a contact-type area-varying capacitive displacement sensor

Kang, Daesil; Moon, Wonkyu

doi:10.1016/j.sna.2012.09.011

Cited by 18 publications

(9 citation statements)

References 11 publications

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“…However, pure SnO 2 gas sensors have several limitations such as poor selectivity [4], slow recovery [5] and high working temperature [6]. To date, many researchers have taken measures to improve its gas sensing performance, such as doping various elements and compositing several sensing materials [7,8]. In addition, an effective strategy which has been effectively demonstrated to control the carrier concentration and enhance the response is to construct heterojunctions among different semiconductor oxides [9,10].…”

Section: Introductionmentioning

confidence: 99%

A Simple Dip-Coating Method of SnO2-NiO Composite Thin Film on a Ceramic Tube Substrate for Methanol Sensing

Wang

et al. 2019

Crystals

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In this work, SnO2-NiO composite thin film was successfully grown on a ceramic tube substrate directly by a simple dip-coating method combined with annealing. Characterization analysis demonstrates that uniform SnO2 film consists of a great number of nanospheres and NiO grows on SnO2 as an agglomerated block. In comparison to the pure SnO2 sample, the SnO2-NiO composite thin films gas sensor exhibits superior methanol sensing properties at 225 °C. The gas response to 10 ppm methanol reached 15.12 and the response and recovery times were 8 s and 7 s, respectively. The excellent selectivity and recovery rate are explained by the unique properties of the NiO semiconductor and the higher sensor response is attributed to the pivotal heterojunction effect.

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Section: Introductionmentioning

confidence: 99%

A Simple Dip-Coating Method of SnO2-NiO Composite Thin Film on a Ceramic Tube Substrate for Methanol Sensing

Wang

et al. 2019

Crystals

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“…As the target function approaches the minimum value with each iteration, deviations could occur with respect to the step value β (n) that was obtained from Equation (16). In order to obtain the optimal step values in the iteration direction, Brent's algorithm [21] was used to derive the approximate optimal value β (n) .…”

Section: Brent's Algorithmmentioning

confidence: 99%

“…In 2012, Lei et al [15] proposed a quartz crystal capacitive sensor that consists of a uniplanar scattering-field capacitance and a piezoelectric resonator for high sensitivity response (3.05 Hz/µm in the range of 20-200 µm). In the same year, Kang et al [16] proposed a low-power high-resolution capacitive sensor for fast vibration measurements. As shown in the studies that were reviewed above, the high precision and better resolution of capacitive sensor testing were the main reasons for measuring the diaphragm displacement of a miniature transducer with a composite metal membrane in this study.To identify the nonlinear parameters, among the conventional optimization methods for parameter estimation, such as the Stochastic Gradient Descent (SGM) [17], RMSProp and ADAM [18], Conjugate Gradient method (CGM) [19], and Broyden Fletcher Goldfarb Shanno Method (BFGS) [20], are the incremental gradient descent based iterative method for optimizing a differentiable objective function.…”

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confidence: 99%

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confidence: 99%

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Parameter Optimization Method for Identifying the Optimal Nonlinear Parameters of a Miniature Transducer with a Metal Membrane

2018

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This study proposes a parameter optimization method for identifying the optimal nonlinear parameters of a miniature transducer with a metal membrane. Specifically, a nonlinear lumped parameter model (LPM) of a miniature transducer that accounts for predicted displacement in a manner that is consistent with the displacement measured by a high-precision capacitance micro-displacement sensor is proposed. To avoid application of the proposed optimization method to an ill-posed problem, this paper proposes a constrained equation that is derived from the relationships of nonlinear parameters. The Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm is used to minimize the objective function in order to obtain an appropriate solution from the proposed nonlinear LPM. The numerical simulation results and a discussion of the experiments are presented. The numerical simulation verification demonstrated that the presented method can estimate the suitable nonlinear parameters for the displacement with errors. With regard to empirical verification, the empirical investigations showed that the proposed method could accurately assess the nonlinear parameters of a miniature transducer with a metal membrane.Electroacoustic measurement is characterized by multiple categories and methods [2]. Each measurement provider formulates different instruments and procedures for transducers with different dimensions. Different methods have been applied by scientists in the past, such as the added mass method [1,3] and the optimization method [4], for transducer's linear parameters estimation. When the miniature transducer is driven in the large signal domain, abnormal vibrations have been observed due to large input signal and increased voltage imposed on voice coil for its displacement [5]. The moving diaphragm that was activated by pneumatic pressure [6] demonstrated that the transducer's model parameters cannot remain linear, but the performance of the transducer can be evaluated by position-dependent parameters [7] as nonlinear parameters. In 1990, Klippel [8] proposed a dynamic measurement system and used a high-precision laser vibrometry and noise signal to measure the linear and nonlinear parameters of a transducer LPM. The nonlinear parameters generate nonlinear effects, such as harmonic and intermodulation distortion; thus, the system that was proposed by Klippel is often used for transducer development, production, quality control, and diagnostics [5,9]. Faifer et al. [10] proposed a nonlinear LPM to identify the coefficient of stiffness K m (x) and the force factor (Bl) and investigated the reduction of 2nd-3rd harmonic distortions by transducer parameter linearization. A simulation method [11] uses finite element analysis for the identification of the nonlinear parameters early, which is the meaningful way of characterizing the transducer in the product development process. In 2001, Mihelich proposed [12] a parameter optimization method for minimizing the cost function between the predicted sinusoid type of displacements and the mo...

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“…Moon et al developed a contact-type linear high resolution encoder-like capacitive displacement sensor [ 8 ]. The sensor displayed significantly improved sensitivity without a reduction in the measurable range.…”

Section: Introductionmentioning

confidence: 99%

Novel EMD-Based Extraction Approach of Electric Field Fringe Impacts on a Micro Capacitive Displacement Sensor

2018

Micromachines

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This paper presents an EMD (empirical mode decomposition)-based extraction approach to decouple the electric field fringe component impacts on the nonlinearity errors of a micro encoder-like capacitive displacement sensor. A calculated capacitance model built under Maxwell’s equations against the impacts of electric field fringe component indicates that signals of this sensor are all in periodic co-sinusoidal waveforms. Applying the proposed EMD scheme, signals are decomposed into sets of intrinsic mode functions (IMFs) and a residual, in which a fundamental component represents all the features of sensor signal and reserves the local information. Interpreting sensor information from the extracted component instead of the original signal drastically diminishes the impacts of electric field fringe effect. Results from a test bench shows that after applying the EMD-based extraction approach, waveform errors were decreased from over 4.18% to less than 0.89%. Nonlinearity of the interpreted displacement was decreased from 1.54% to 0.29% for 8 mm stroke.

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Electrode configuration method with surface profile effect in a contact-type area-varying capacitive displacement sensor

Cited by 18 publications

References 11 publications

A Simple Dip-Coating Method of SnO2-NiO Composite Thin Film on a Ceramic Tube Substrate for Methanol Sensing

A Simple Dip-Coating Method of SnO2-NiO Composite Thin Film on a Ceramic Tube Substrate for Methanol Sensing

Parameter Optimization Method for Identifying the Optimal Nonlinear Parameters of a Miniature Transducer with a Metal Membrane

Novel EMD-Based Extraction Approach of Electric Field Fringe Impacts on a Micro Capacitive Displacement Sensor

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