Wen Yuan Chen

Design, Fabrication and Analysis of Microrobotic Insect Wings and Thorax with Different Materials by MEMS Technology

This paper presents a feasibility step in the development of biomimetic microrobotic insects. Advanced engineering technologies available for applications such as the micro-electro-mechanical system (MEMS) technologies are used. A flapping-wing flying MEMS concept and design inspired from insects is first described. Then different kinds of materials used feasibly for flapping-wing microrobotic insect by MEMS technology, such as SU-8, Titanium alloy and Parylene-C, are discussed. And artificial insect wings and thoraxs with different materials by MEMS Technology are fabricated and analyzed. Finally, summarize the paper and propose future research priorities.

A PCR Chip with Reusable Electrodes and its Temperature Analysis

This paper presents a new micromachined PCR chip with separable electrodes part and reaction chamber part. The electrodes part, employing Pt film resistor as heaters and sensors, is reusable, and the chamber part is a disposable PDMS-GLASS bonded structure. This PCR chip with reusable electrodes can largely reduce fabrication cost. COMSOL software is used to simulate the temperature distribution of the designed chip and then use infrared thermometer (NEC R300SR) to verify temperature distribution of the fabricated chip. The test results turned out to perfectly fit the simulation of temperature distribution, which provides reliable basis for further PCR amplification experiment.

The Study on After-Treatment System and Algorithm of Piezoelectric Micromachined Modal Gyroscope

Piezoelectric Solid-State Micro-machined Modal Gyroscope is a new kind of gyroscope sensor based on MEMS. According to the characteristics of the gyroscope signal, the after-treatment processing system is designed and implemented, including A/D convertor by AD7656 and data storage by SD card. After applying Kalman filter to the digital signal on DSP, 71.8% decrease of standard variance of initial signal is achieved remarkably, which lays the foundation for the practical application of piezoelectric micro-machined modal gyroscope.

Design and Fabrication of a Novel Biaxial Piezoelectric Micro-Gyroscope

Despite the popularity of piezoelectric vibratory micro-gyroscope in the past decades for their small size, low cost, batch fabrication and energy efficient, most of them can only detect single axis angular rate. In this paper, a novel biaxial piezoelectric micro-gyroscope fabricated with PZT wafer is proposed. To acquire two-axial angular rate sensing, a bouncing mode of the vibrator is utilized as the drive mode and two rocking modes are used as the sense modes. PZT is used as the vibration body instead of transducer, which enhances the drive and sense efficiency of the sensor. In this paper, the structure and working principle of the novel biaxial piezoelectric micro-gyroscope are introduced firstly. In addition, modal analysis has been made to research the voltage distribution of the piezoelectric vibrator and the drive and sense electrodes of the gyroscope are designed. By the optimization design of the proof mass, the frequency split between the drive mode (bouncing mode) and sense modes (rocking modes) is reduced and the sensitivity of the gyroscope is improved. Harmonic analysis has been made to research the Coriolis Effect of the gyroscope. The data get from the harmonic analysis is demodulated by Matlab and the sensitivity is given. The simulation results verify the principle of the novel biaxial piezoelectric micro-gyroscope. With the optimized design, the sensor is fabricated with MEMS technology at last.

A Novel Flexible Shear Stress Sensor Array with Double Hot-Wires Based on MEMS

Design, production and calibration of a novel flexible shear stress sensor array with double hot-wire based on MEMS are presented in this paper, which can be applied to measure the surface shear stress of air craft or underwater vehicles. The sensor array is successfully fabricated by MEMS process, the electrical bond pads of which are located at the backside, thus greatly reducing the interference of the measured flow filed. The calibration has been carried out in the wind tunnel experiment, and the value of calibration factor is 8.35mV/ (m/s) in a flow velocity range from 0 to 35 m/s. The results of test experiments prove that the shear sensor array is well capable of measuring the flow velocity of boundary layer.

A Simple and Practicable PCR-Microchip with Bubble-Free Stationary Chamber

This paper reports on a simple and practicable biochip for polymerase chain reaction (PCR). The micro biochip (12mm×12mm) is a hybrid type which is composed of a polydimethylsiloxane (PDMS) cover with a hexagonal chamber and a glass substrate integrated with platinum (Pt) microheater and microsensor. Bubble formation has been reported as a big problem with PCR chips. In this paper we present a simple and practicable operation schedule to get a bubble free chip, in which a successful PCR process was guaranteed.

Design Optimization of BAW Micro-Piezoelectric Disk Gyroscope through Finite Element Method

Micro-piezoelectric disk gyroscope (MPDG) is a miniaturized inertial sensor that uses a pair of degenerate bulk acoustic wave (BAW) modes to detect the angular velocity. To improve the performance of MPDG, there should be an effective method to design this resonant structure. In this paper, the frequencies of drive and sense mode are obtained when the radius of the MPDG varies from 2.2mm to 3.0mm and the thickness of the MPDG varies from 0.8mm to 1.5mm through finite element analysis (FEM). Using a fitting method, the empirical formulae with an excellent fit are induced to predict the influence of the radius and the thickness of the MPDG on the drive and sense mode frequencies. Based on these empirical formulae, the mode-matched equations are introduced. Moreover, the structure parameter of support pin and electrodes are optimized with FEM. These results can be used to design a piezoelectric disk gyroscope.

Study on Driving Technology of Piezoelectric Solid-State Micro Gyroscope

In order to compensate the noise brought by piezoelectric gyroscope or external environment and track the resonance frequency, Closed Loop Driving Circuit (CLDC) of piezoelectric solid-state micro gyroscope is proposted in the paper which will stabilize the driving voltage value and keep the resonance frequency tracked. CLDC mainly contains Phase Lock Loop (PLL) circuit, Automatic Gain Circuit (AGC). Experimental results show that the fluctuation of reference voltage is within ±7mv, while the fluctuation of reference voltage in Open Loop Driving Circuit (OLDC) without noise compensation is ±23mv. The frequency of CLDC drifts within 0.03 kHz with the resonance frequency of 357.9 kHz while the OLDC can’t track any drifting.

Modal FEM Analysis Using Weak Form Equations for a Microgyroscope with Bulk Giant Magnetostrictive Material (GMM) Resonator

The structure and operation principle of a novel solid MEMS gyroscope with bulk giant magnetostrictive material (GMM) resonator are presented. A finite element method (FEM) for modal analysis of the GMM resonator is employed in which the fundamental magnetoelastic governing equations of the GMM are solved numerically using weak form equations of COMSOL Multiphysics. For a bulk GMM with size of 4×4×4 mm3, it is found that the third order vibration mode with frequency of 182 kHz meets working vibratory mode of the gyro sensor, which is verified by harmonic response analysis. Compared with analogy method which simulates the GMM as piezoceramics, this method is more practically reflect the operation state of GMM resonator of the microgyro due to consideration of Maxwell force in the weak form equations. This paper provides important basis for further full magnetic electromechanical coupling analysis of the microgyroscope.

On-Chip Bio-Micro Separation and Operation Effected on the Diamagnetic Levitation with MEMS

This paper reports an overview and development of the diamagnetic levitation technology. The paper presents the characteristic and application of the magnrto-Archemides levitation and also the key factors in the applications. In the paper, the simulation models are built, and analyzed with MEMS technology. Finally, technology development and the application, especially in the field of biomedicine, are prospected.