Key Engineering Materials Vols. 609-610

Abstract: This paper reports a novel piezoelectric quartz crystal double-ended tuning fork (DETF) resonator with vibration attenuation structure, which is suitable for high resolution force sensing. The DETF resonator was designed to work in the fundamental flexure mode, and manufactured along the Y direction based on the Z-cut quartz crystal wafer using photolithographic and anisotropic chemical etching of quartz crystal. The resonance frequency of the DETF resonator is 39.1KHz. Vibration amplitude of the DETF resonator was measured and the experimental results show that vibration amplitude of the joint of DETF resonator is almost three orders of magnitude lower than that of midpoint of DETF, and the quality factor is up to 7750 at ambient condition and 59600 in vacuum, respectively.

Abstract: This paper is based on a meteorological detection system, which contains MEMS barometric pressure sensors, MEMS temperature sensors, MEMS humidity sensors and GPS receiver. The micro control unit of this system is based on C8051F120 microcontroller. By Comparing SHTXX series of temperature and humidity sensor and PT100 thermal resistance, we obtain a measurement scheme that can measure environment temperature rapidly and relatively accurate when the volume, weight and power are limited. It can meet the harsh environments and high reliable needs. In addition, the simulation analysis and the experiment of temperature are carried out.

Abstract: With vision feedback the binocular micro stereovision system based on stereo light microscope (SLM) makes it possible to achieve 2D/3D high accuracy auto-positioning, 3D information extraction, 3D shape reconstruction and 3D measurement. Therefore, it is extensively used in micro robot navigation, micromanipulation, micro assembly and bioengineering, etc. To improve the key problems of low accuracy, refraction and occlusion in micro stereovision measurement, a novel micro stereo vision system is built based on optical theory and digital image processing. Then, the nonlinear correlation between optical paths of the micro stereo vision system is studied and the environment adaptive nonlinear model is established. On this basis, the coupling mechanism of multi-refraction and occlusion with micro-projection nonlinear model is proved, and multi-refraction variable refractive index correction and micro stereo occlusion reconstruction algorithms are developed. It realizes synchronization observation in larger field of view, rapid non-contact accuracy positioning and 3D measurement based on stereovision to solve the pivotal problems of accuracy positioning and measure in the chip encapsulation, micro assembly and the micro manipulation.

Abstract: Micron and nanometer dimensional metrology is an important part of integrated circuits manufacturing system and nanofabrication research work. Semiconductor device feature size has shrunk from the micron to dozen of nanometers. How to watch the micro structure clearly, identify its edge, and measure its dimension accurately are the major issues that need to be research. In this paper, a metrological scanning electron microscope (M-SEM) system with precision stage and laser interferometer is presented. Furthermore, this paper focuses on demonstrating a metrological SEM image edge detection algorithm which is the essential part of the metrological SEM system to realize the measurement of line width. The procedure of the algorithm is that SEM image is first analyzed by noise type according to the histogram characteristics. Then the image noise is reduced by specific filters. Furthermore, a specific interesting object image region is selected and pixel gray level values of the region are obtained by line scan. SEM image edges are determined by the characteristic of the pixel information in two possible cases. This algorithm preserves the edge details of the original image and detects the image edge automatically in an easy and fast way.

Abstract: In this paper, a novel partial sensorless control (PSC) has been tailored to multi-DOF precision positioning issue for Sawyer motor-based planar motion stage. For the position estimation, a Sliding Mode Observer based technique has been implemented. We investigate the positioning performance on open-loop, closed-loop and PSC by experiments. The results of experiments have verified that PSC is an available way to maintain travel range and reduce the cost for precise position sensing while without so much sacrifice on positioning accuracy comparing with closed-loop control in all-axis for the stage.

Abstract: In order to achieve accurate positioning of the detector in the pipeline, explore the affection of the different seasons and soil moisture on the ground calibration, then ground marking studies by MEMS acoustic vector sensor is proposed. To select four seasons in one year to do comparative experiment, analysis the signals and drawn the angle table. Secondly, we select the most accurate period, to research the impact of the dry soil and wet soil. The results show that: The result of direction on Autumn is the most accurate season, the difference between angle of the measurement point and the true angle can be achieve to 1.051 degrees; On Winter, the relative error is the largest, the orientation angle is the most inaccurate; it is more accurate when the soil is dry than it in wet soil. Far-reaching meaning has been provided in this research.

Abstract: Semi-strapdown inertial measurement method provides a new solution for the high-precision measurement on flight attitude of high-spinning ammunition, while the specific set of components in the semi-strapdown application will cause a series of errors. This paper mainly analyzes the generation mechanism of motor speed fluctuation error and the misalignment error in coupling axis. Then the instantaneous motor speed measurement method based on the high-precision gyroscope is designed and the misalign model of coupling axis is set up, MEMS inertial measurement area centripetal force equation under the condition of high speed is worked out, and accuracy error parameters affecting the measurement are obtained. Finally, the paper provides corresponding error compensation method and comparative tests are conducted. The results show that the compensated system improves the accuracy of attitude angle calculating and the error has been effectively suppressed.

Abstract: Considering that the MEMS Gyroscope used in rotating carrier has the problems of small range and low measurement accuracy, the tri-axial angular rate measurement system based on two MEMS accelerometers used for rotating carrier was presented in this paper. The system has the advantages of large measurement range, anti-high overload, simple structure, small volume and low price. From the principle of the tri-axial angular rate measurement system, the mathematical model of the system was established and the mechanics model of the system was discussed. The different processing method of the output signal in each condition was summarized based on the mechanics model. Finally, the semi-physical simulation experiment was done to verify these theories. The experimental results show that the system scheme is feasible and has obvious advantages in the range and measurement accuracy.

Abstract: A new type of measurement and recording device for the nuclear fuel transport cask was presented on this paper. With the view to the characteristics of specific application object, the system has been designed with the integration of the MEMS sensors. Several kinds of MEMS sensors include MEMS gyroscopes, MEMS accelerometers, MEMS magnetometers and MEMS pressure sensors are integrated together with embedded CPU, micro GPS receiver, and communication unit. With the conception of the modularization, the multi-subsystem (including: stainless steel sleeve structure, shock absorbers, sealed loader, MEMS sensor components, FLASH memory, power supply components, wireless communication components, etc.) was combined to a new transport cask of nuclear fuel. The low power, low cost, high integrate MEMS sensor system can achieve date of the whole process of nuclear fuel conveying condition, and alarm at the licensing of circumstances beyond. The new nuclear fuel transport cask system include: stainless steel sleeve structure, shock absorbers, sealed loader, MEMS sensor components, FLASH memory, power supply components, wireless communication components. The self-programmed software provides a means to analyze all the data during the whole transport process. The sensors’ output, attitude variety, temperature, acceleration, GPS trace can be analyzed simultaneity or independently. Using the data recorded, System Identification is performed to find the final health status of nuclear fuel.

Abstract: A compact polarization beam splitter (PBS) based on a silicon waveguide-silver nanoribbon-silicon waveguide is proposed and demonstrated numerically by utilizing the evanescent coupling between a strip-nanowire and a nanoslot waveguide. Two-dimensional (2-D) FDTD simulations were performed to elucidate the properties of surface plasmon polaritons (SPPs) in this device made from silicon-metal-silicon, and were found to agree well with the theoretical predictions. TE and TM polarized light are respectively separated into two different output ports of Y-shaped silicon waveguide in which the coupling efficiency is 62% and 45% for 1.55μm wavelength, respectively. The proposed PBS structure could be utilized to develop ultracompact optical polarization modulating device for large-scale photonic integration and optical information processing.