This paper presents a method to derive the gyro response time of thermal expansion flow in Z-axis micro-electro-mechanical systems (MEMS). First, the structure of the thermal expansion gyro is given and its working principle is explained in detail. Secondly, according to the sensitive mechanism of the thermal expansion gyro and its heat transfer mode, the theoretical model of the response time of the thermal expansion gyro is derived, and the calculation formula of the response time of the thermal expansion gyro is given. Finally, in order to verify the response time calculation formula derived in this paper, the finite element method is used. Based on the three-dimensional physical model of the thermal expansion gyro, the theoretical response time of the gyro is calculated and verified. The results of calculation and finite element verification show that: (1) the theoretical model and formula of response time of thermal expansion gyro are in agreement with the verification data; (2) With the increase of the thermal conductivity of the gas, the area of the thermal wire, and the decrease of the specific heat capacity and density of the gas, the response time gradually decreases. (3) The gyro response time calculated for Z-axis thermal expansion flow is 669.88 ms. The formula for calculating the response time of thermal expansion gyro presented in this paper lays a theoretical foundation for optimizing the response time of thermal expansion gyro.

A new sensitive structure of a low-coupling heat flow biaxial MEMS accelerometer is proposed and its sensitivity mechanism is investigated. A three-dimensional model of the sensitive structure was created by COMSOL, and the temperature field of the sensitive structure was calculated using the finite element method. The results show that the accelerometer has a temperature sensitivity of 1.71 K·g-1in the X-axis, 1.69 K·g-1in the Y-axis, 0.7% cross-coupling, and the sensitivity of both X-axis and Y-axes was 1.5 mV·g-1with a heater power of 5mW and an acceleration of [-1~1] g. The accelerometer is characterized by a high sensitivity and a low cross-coupling, which lays a theoretical basis for the optimization of the structure in the following years.

In this paper, a structure of high robustness pressure sensor based on heat conduction is proposed and its mechanism is studied. The temperature field in the structure of a high robustness pressure transducer based on heat conduction is calculated by COMSOL, and the temperature difference under the corresponding pressure is calculated. The calculation results based on the three-dimensional physical model of the sensor show that the temperature difference of the highly robust pressure sensor based on heat conduction decreases with the increase of pressure, and the pressure of the sensor is inversely proportional to the temperature difference, The temperature sensitivity of the high robustness pressure sensor based on heat conduction in the range of 0 ~ 49N is -0.021 K/N and the nonlinearity is 11.02%. The temperature sensitivity of the high robustness pressure sensor based on heat conduction in the range of 50 ~ 60N is -1.184 K/N and the nonlinearity is 7.85%. Through the establishment of the three-dimensional physical model structure of the high-robustness pressure sensor based on heat conduction and the calculation results of the sensor, the mechanism of the high-robustness pressure sensor based on heat conduction is revealed, which lays a theoretical foundation for the subsequent optimization of the parameters and structure of this kind of sensor.

In this paper, a structure of a flexible temperature sensor is proposed. And its sensitivity mechanism is investigated. A physical model is established based on the proposed structure. A mathematical model is established based on the actual situation. A 3D model of the structure is created by COMSOL software. In which the mathematical model is studied for this sensor. The temperature field within this sensitive structure was calculated using the finite element method. The corresponding material properties in the sensor structure were set. Setting up the physical fields required for operation. Mesh this 3D structure. Setting the external ambient temperature. Setup of the type of study according to the actual situation. The sensor detects the ambient temperature. Calculations are made based on the results of the finite element method, combined with the corresponding theoretical formulas. It is calculated that the temperature coefficient of resistance is 0.0316/° C in the temperature range of -18~80 ° C, and the nonlinearity is 1.36%. There results conclude that the relationship between temperature and resistance is proportional. This lays a theoretical foundation for the optimisation of subsequent structural studies of flexible temperature sensors. It facilitates further performance enhancement in subsequent research. This promotes the research progress in related fields.

We propose thermal expansion flow gyroscopes with self-balancing resistance and study their impact resistance. In this paper, a thermal expansion flow gyro with self-balancing resistors is used as the research basis, aiming to improve the environmental adaptability of the gyro through technological innovation. The thermal expansion flow gyro contains an upper chamber, a lower chamber and a base layer, which contains four thermistors, two heating resistors and two balancing resistors. In order to improve the detection accuracy of the Wheatstone bridge, the balancing resistors and thermistors are fabricated using the same MEMS process, which ensures that the balancing resistors are highly consistent with the thermistors in terms of material, structure, and process, and achieves a high degree of matching and stability. Based on the above analysis, we carried out a finite element analysis of the impact resistance of the self-contained balancing resistor thermal expansion flow gyro. The experimental results show that the impact resistance of this thermal expansion flow gyro can reach 14,752 g when the load is applied in 0~10ms, which fully proves its high stability in harsh environments. The results of this study will provide a reference for subsequent gyro performance studies.

The sensitivity mechanism of a thermal oscillator-type biaxial MEMS angular velocity gyro was revealed. The temperature field inside the sensitive structure was calculated based on the biaxial sensitivity principle, the vibration mode of the thermal oscillator and the gyroscopic effect. The results show that: (1) A stable temperature field is formed inside the sensitive structure after 1.8s of power-on. (2) When there is angular velocity loading, the thermal oscillator moves with the input angular velocity, causing the temperature field to shift, and the temperature difference $\Delta T_{\mathrm{Y}}(\Delta T\mathrm{x})$ between the two hotlines set symmetrically in the two orthogonal $\mathrm{Y}(\mathrm{X})$ directions shows a linear growth with the increase of the input angular velocity $a_{x}(a_{y})$ , and the average temperature sensitivity of X and Y axes is 121 mK/°/s. (4) According to the input-output $\omega_{x}-VY\text{out}$ and $\omega_{y}-VX\text{out}$ characteristic curves, the mathematical model is obtained, and the sensitive mechanism is revealed. The average sensitivity of X and Y axes is 0.091mV/°/s, the average nonlinearity is 1.86%, and the average cross-coupling is 2.3%. This paper provides a practical theoretical foundation for the optimized structure.

该文提出了一种高灵敏度的热膨胀陀螺,并对其敏感机理进行了研究.通过COMSOL创建了该结构的二维模型,并对其进行了有限元分析.结果表明,输入功率为5 mW,输入角速度范围为-1 000～1 000(°)/s时,提出的热膨胀陀螺温度灵敏度为2.12 mK·[(°)/s]-1,具有陀螺效应,且热膨胀陀螺灵敏度为1.98 mV·[(°)/s]-1,非线性度为7.64％.与之前的结构相比,陀螺灵敏度有提高.该高灵敏度热膨胀陀螺具有抗冲击能力强,制作成本低,工艺简单及可靠性高等优点,可用于航天、消费电子及军事等领域.

A single-axis MEMS thermal expansion flow gyro with an independent sensitive unit is proposed and the principle of independent sensitivity to improve gyro sensitivity is revealed. The temperature field inside the sensitive element of the independent sensitive gyro is calculated by using the finite element method. The calculation results show that (1) the sensitivity is improved from 1.07 K/rad/s to 2.43 K/rad/s compared with the conventional temperature sensitive method.(2) The optimal structural sensitivity of the gyro at angular velocities [0 rad/s, 10 rad/s] was 7.67 K/rad/s with a nonlinearity of 11.08% at a heater distance of 4 mm, an upper chamber height of 3 mm, and a heater power of 70 mW. The results provide a theoretical basis for the structural design and performance optimization of the thermal expansion flow gyro.

该文揭示了一种动热源摆式单轴微机电系统(ME MS)热加速度计的敏感机理.在给出敏感结构原理的基础上,通过建立二维物理研究模型、划分网格、加载加速度等方法对敏感结构内的温度场进行了计算.结果表明,开机1.8 s后在敏感结构内形成了一个稳定的以动热源为中心的温度场;输入加速度a时,动热源沿着加速度方向偏移,温度场随之偏移,敏感轴方向上对称设置的两个热线温差ΔTX随着输入加速度a的加大而呈线性增长,温度灵敏度为7.1×10-2 mK/g.根据输入-输出(a-VXOUT)特性曲线给出数学模型,得到该加速度计灵敏度为0.5 V/g,非线性度为2.8％,从而揭示了敏感机理.

A new basic structure based on a bidirectional thermally expanded flow gyro is proposed and its sensitive mechanism is revealed. The temperature field inside the sensitive element of the bi-directional thermally expanded flow gyro is calculated by using the finite element method and a three-dimensional model with COMSOL. The calculation results show that the bi-directional thermal expansion flow gyro has gyroscopic effect, the input angular velocity is in [−40rad/s, 40rad/s], the structural sensitivity of the gyro is 0.9293K/rad/s. The gyro has the advantages of high shock resistance, high sensitivity, cross-coupling suppression and simple process, and can be used in electronic equipment, aerospace and medical instrumentation.

该文提出了一种单轴微机电系统(MEMS)热膨胀流陀螺的基本结构,并揭示了其敏感机理.通过有限元法,利用COMSOL Multiphysics建立了陀螺的三维模型,在有无角速度时对陀螺敏感元件的温度场和等温线变化情况进行计算.结果表明,单轴MEMS热膨胀流陀螺具有陀螺效应,输入角速度为[-1 080(°)/s,1 080(°)/s],陀螺的结构灵敏度为0.053 9 K/[(°)·s-1],非线性度为14.13％.

In this paper, a thermal expansion gyro was proposed, its sensitive mechanism was studied, and the effect of its heating method on sensitivity was explored. A 2D model of the structure was created by COMSOL, and finite element analysis was performed on it. The results show that: The input power is 5mW, when the input angular velocity range is - 400(°)/s~400(°)/s, The temperature sensitivity of the proposed complementary square wave thermal expansion gyro and DC loaded thermal expansion gyro are 6.39 mK·[(°)/s] -1 and 0.621 mK·[(°)/s] -1 . The sensitivity is respectively 2.39 mV·[(°)/s] -1 and 0.232 mV·[(°)/s] -1 . The nonlinearities are respectively 14.5% and 14.3%, which has a gyroscopic effect; Complementary square wave heating method with greater sensitivity. The gyro sensitivity is improved compared to the previous structure. The high-sensitivity thermal expansion gyro has the advantages of strong impact resistance, low production cost, simple process, and high reliability, and can be used in aerospace, consumer electronics, military and other fields.

To explore a simple, fast and high-precision paper-based devices fabrication method, a paper-based microfluidic devices fabrication method based on CO2 laser cutting technology is proposed in this paper, in which the filter paper is fixed with aluminum foil, and the hydrophobic barrier is formed by laser cutting the adhered filter paper. High-precision paper-based devices can be produced quickly and in large quantities due to the adjustable laser power magnitude and movement speed. The minimum hydrophilic channel width of the paper-based devices made by this method is $76\pm 2\ \mu\mathrm{m}$ and the minimum hydrophobic barrier width is $90\pm 3\ \mu\mathrm{m}$ , which greatly reduces the size of the paper-based devices. The paper-based devices made by this method for the detection of nitrite concentration obtained good linearity and good agreement with the spectrophotometry for the detection of nitrite. The paper-based devices made by laser cutting method are simple, low manufacturing cost, stable process method and good consistency for mass production, which provides an effective means for the research and wide application of paper-based devices.

随着社会的发展,我国人口老龄化越来越严重,因而增多了关于养老服务的需求.但目前很多养老机构的管理不规范,设备老旧不智能,没有跟上时代的步伐.老年人一旦发生意外情况,很难及时发现和救助.对此,文章提出一种老人摔倒求助视频检测系统,系统由一个微型计算机以及其自带的摄像头和一台上位机构成,通过摄像头对养老院老人进行拍照,微型计算机将拍摄的照片上传至上位机,在上位机中设计一个卷积神经网络模型用于检测老人是否摔倒和求救,便于及时提醒监护人施以援手.

为了探究纸基微流控芯片的材料参数和微通道结构对液体流动特性的影响,使用COMSOL仿真软件建立微通道模型,通过更改纸基的孔隙率和渗透率,设计新的微通道结构,对液体在纸基材中的流动特性进行仿真研究;仿真结果显示孔隙率和渗透率越大纸基材的液体吸入量越大,液体渗透速度越快;液体在正梯形结构的纸基微通道上具有最佳的流动特性.纸基材料的参数和流道结构对液体的流动特性具有一定影响,其对于纸基微流控芯片的制作选材与芯片设计具有重要意义.

文章研究了一种不同于其他产品的新型宠物自动投食器——基于卷积神经网络的猫狗识别自动投食器.与市面上其他投喂对象单一的宠物自动投食器相比,该款投食器能够根据图像识别结果去投喂多种类型的宠物,例如猫、狗.该款投食器将来能够运用在宠物家庭、宠物店、宠物主题餐厅等猫狗混养的场所.该装置使用的技术主要涉及机器学习的相关内容,通过训练和搭建卷积神经网络来准确识别猫、狗的图像,并且根据图像识别结果投喂相应的猫粮或者狗粮.同时,利用安装在机身上的红外传感器作为投喂开关,负责生物接近检测以判断投食器是否需要进行投喂,从而使整个投食过程更加合理与智能.

Micromachined gyroscope is easy to be affected by the working environment temperature, leading to temperature drift. In order to reduce the gyro output error caused by temperature change, the polynomial fitting algorithm is used to model and compensate the temperature drift error in this paper. After compensation, the zero output of the gyro is near 0°/s and does not change with temperature changes, the accuracy is greatly improved. The experimental results show that the compensation algorithm can effectively suppress the influence of temperature on the micro gyro sensor.

Micromachined gyroscope is easily affected by the working environment temperature and has temperature drift. In order to reduce the gyro output error caused by temperature change, the BP neural network is used to model and compensate the temperature drift error. After compensation, the zero output of the gyro is near 0°/s and does not change with temperature changes, the accuracy is greatly improved. The experimental results show that the compensation algorithm can effectively suppress the influence of temperature on the micro gyroscope sensor.

提出了一种单热源热流陀螺仪并揭示了它的敏感机理,即在哥式力的作用下,并联的加热丝形成的单热源所产生的热流会引起输出电压的变化,通过建立角速度与输出电压的关系,进而检测Z轴角速度.通过有限元的方法,利用COMSOL Multiphysics对该陀螺的敏感元件在有无角速度时温度场和等温线的变化情况进行了计算.计算结果表明,单热源热流陀螺仪具有陀螺效应,在±20 rad/s角速度范围内,其输入角速度与输出电压的比例系数k为0.005 V/(rad·s-1),灵敏度为5.29×10-3 V/(rad·s-1),非线性度为6.81％.该研究为后续的结构改进、性能优化奠定了理论基础.