Self-calibration and algorithm of sample set of piezoresistive pressure sensors

Aiming at piezoresistive pressure sensors, this paper studies simulation of standard pressure by using benchmark current source and self-calibration of the sampling data characteristics. A data fusion algorithm for sample set is presented which transforms a surface problem into a curve fitting and interpolation problem. The simulation result shows that benchmark current source simulating pressure is successful and data fusion algorithm is effective. The maximum measurement error is only 0.098 kPa and maximum relative error is 0.92% at 0-45 kPa and -10-45~C.

A fiber Bragg grating based earth and water pressures transducer with three-dimensional fused deposition modeling for soil mass

A novel fiber Bragg grating(FBG)sensor with three-dimensional(3D)fused deposition modeling(FDM)approach is proposed for effective stress measurement in soil mass.The three-diaphragm structure design is developed to measure earth and water pressures simultaneously.The proposed transducer has advantages of small size,high sensitivity,low cost,immunity to electromagnetic interference and rapid prototyping.The working principle,design parameters,and manufacturing details are discussed.The proposed transducer was calibrated for earth and water pressures measurement by using weights and a specially designed pressure chamber,respectively.The calibration results showed that the wavelength of the transducer was proportional to the applied pressure.The sensitivity coefficients of the earth and water pressures were 12.633 nm/MPa and 6.282 nm/MPa,respectively.Repeated tests and error analysis demonstrated the excellent stability and accuracy of the earth and water pressure measurements.The performance of the proposed transducer was further verified by a model experimental test and numerical analysis,which indicated that the proposed transducer has great potential for practical applications.

Automatic modeling algorithm of stochastic error for inertial sensors

This paper proposes an automatic algorithm to determine the properties of stochastic processes and their parameters for inertial error. The proposed approach is based on a recently developed method called the generalized method of wavelet moments (GMWM), whose estimator was proven to be consistent and asymptotically normally distributed. This algorithm is suitable mainly (but not only) for the combination of several stochastic processes, where the model identification and parameter estimation are quite difficult for the traditional methods, such as the Allan variance and the power spectral density analysis. This algorithm further explores the complete stochastic error models and the candidate model ranking criterion to realize automatic model identification and determination. The best model is selected by making the trade-off between the model accuracy and the model complexity. The validation of this approach is verified by practical examples of model selection for MEMS-IMUs (micro-electro-mechanical system inertial measurement units) in varying dynamic conditions.

Adaptive Volterra series model for nonlinear sensor compensation

A novel performance enhancement method of nonlinear sensor based on the Volterra series model is proposed. The Volterra series model, which is considered a nonlinear filter that can reduce sensor noise, presents an effective way for modeling and compensating a nonlinear sensor. In the experiment, the low accuracy pressure sensor MPX10 was used as the actual object, and higher accuracy sensor MPX2010 was used as the reference to provide the necessary teaching data for training the Volterra model. The simulation shows that the accuracy of MPX10 changes from 0.354-0.420 to 0.041-0.053 after the Volterra filter is applied. Obviously this scheme can effectively improve the sensor performance. Moreover, the scheme provides greater accuracy and environmental suitability for a nonlinear sensor.

Method to Detect Granary Storage Weight Based on the Janssen Model

This study proposes a new model of granary storage weight detection based on the Janssen model to satisfy the strategic requirements of granary storage quantity detection in China. The model theoretically elucidates the relationship between granary storage weight and bottom/side pressure. A new layout of pressure sensors along the inner and outer rings is also proposed to obtain the pressure value. The experimental results indicate that the detection error of the proposed model is significantly lower than 1% with respect to the low-cost detection system, and this effectively satisfies the actual requirement for real-time monitoring of granary storage quantity.

Calibration Method Based on RBF Neural Networks for Soil Moisture Content Sensor

Temporal and spatial variation of soil moisture content is significant for crop growth,climate change and the other fields.In order to overcome shortage of non-linear output voltage of TDR3 soil moisture content sensor and increase soil moisture content data collection and computational efficiency,this paper presents a RBF neural network calibration method of soil moisture content based on TDR3 soil moisture sensor and wireless sensor networks.Experiment results show that the calibration method is effective...

Modeling of a Linear Scanning 3D Vision Coordinate Measurement System

This paper theoretically analyzes and researches the coordinate frames of a 3D vision scanning system, establishes the mathematic model of a system scanning process, derives the relationship between the general non-orthonormal sensor coordinate system and the machine coordinate system and the coordinate transformation matrix of the extrinsic calibration for the system.

Short-circuit process model in underwater welding using rotating arc sensor

In order to detecting and tracking along the weld seam with rotating arc sensor in underwater welding,the highpressure water environment rotating arc welding hardware platform is established and welding experiments using rotating arc sensor is done. Different radius of rotating arc sensor is used. And the corresponding welding current and voltage is obtained,which is compared with the results of rotating arc sensor short-circuit process simulation model under high-pressure water environment established in this article. The results show that under high-pressure water environment,rotating arc radius should be optimized,otherwise the short-circuit-arcing cycle will transit to a short-circuit-arcing-abruption cycle,making the welding quality poor. At last the critical radius between the short-circuit-arcing cycle and short-circuit-arcing-abruption cycle under high-pressure water environment is obtained.

ANALYTICAL ANALYSIS OF MEMS CAPACITIVE PRESSURE SENSOR WITH CIRCULAR DIAPHRAGM UNDER DYNAMIC LOAD USING DIFFERENTIAL TRANSFORMATION METHOD(DTM)

In this paper, first a circular diaphragm is modeled using the classical plate theory. An analytical solution based on differential transformation method （DTM） and Runge-Kutta method is employed for solving the governing differential equation for the first time. Then the influences of various parameters on central deflection of the diaphragm, stress distribution and capacitance of pressure sensor with a time-dependent pressure are examined. Several case studies are compared with simulations to confirm the proposed method. The analytical results compared with ABAQUS simulation show excellent agreement with the simulation results. This method is very promising for time saving in calculating micro-device characteristics.

高频动态压电式压力传感器结构设计与实验研究

针对激波压力信号快速测量需求的提升,提出了一种基于压电效应的高频动态激波压力传感器结构形式及测量原理。通过分析激波信号的时频特性,确定高频动态压电式压力传感器的性能需求;采用高频动态压电式压力传感器的测量原理,对提出的激波压力测量进行了分析;基于变形协调一致原则,建立了静力学和动力学模型,分析传感器结构参数对灵敏度和固有频率的影响规律;将优化后的传感器三维模型导入ANSYS中进行静力学、动力学和压电耦合分析,验证了传感器结构及其测量原理的可行性。通过准静态标定和动态标定实验,得到传感器的电压灵敏度、非线性度和固有频率等测量性能指标,实验结果表明:研制的高频动态压电式激波压力传感器样机具有高灵敏度3.19 mV/kPa、高固有频率特性95.625 Hz和短上升时间10.45μs特性,能够满足实际测试需求。

基于单片机开发板和3D打印的一种多参数呼吸训练装置的研究开发

目的通过野火骄阳32单片机开发板和3D建模及打印技术进行软硬件开发,实现一种多参数呼吸训练装置的专利样机转化。方法利用野火骄阳32单片机开发板开发应用程序,通过单片机开发板实现流量信号和压力信号的输入,舵机阀、涡轮风机、电磁阀的控制输出与上位机的数据通信等功能;样机非标零部件通过3D建模及打印技术完成制造,并将单片机开发板、标准零部件和非标零部件进行组合以完成样机开发。结果野火骄阳32单片机开发实现了传感器数据采集、运动部件的控制输出、上位机软件的数据上传和接收;3D建模及打印技术实现了非标零部件及机器外壳的制作,以低成本成功制作出样机;样机通过质控仪检测,流量值误差范围为±15%,气道压力值误差范围为±[2%FS(满量程)+4%×实际读数],样机参数精度满足JJF1234-2018《呼吸机校准规范》要求。结论野火骄阳32单片机开发板和3D建模及打印技术的应用,以低成本实现了样机制作,能够为专利的商业转化提供重要参考,为医工专利转化提供了一种新的思路。

基于压力估计的供水管网水力模型校核

供水管网水力模型校核过程中,由于监测点个数较少而校核的参数过多,校核结果往往与实际不符。为使校核结果较为符合实际,提出一种基于压力估计的水力模型校核方法,根据实测监测点压力和入口流量数据估计非监测点的压力,并将估计的节点压力作为校核问题中的已知条件。以管道海曾威廉系数为校核参数,使用多层感知器(Multilayer perceptron,MLP)估计节点压力,使用遗传算法(Genetic algorithm,GA)优化目标函数。案例分析表明,提出的MLP-GA比GA校核效果更好,3个监测点压力绝对误差之和从37.81 m减小到33.65 m,降幅达11.0%;管道海曾威廉系数的绝对误差之和从933.5降低到847.0,降幅达9.27%。

压力传感器温度响应特性校准装置研究

为确保测量数据的准确性,需对压力传感器在高低温环境下温度响应特性参数进行校准,通过开展标准压力源、温度隔离单元、多点测温校准腔等系统设计,研制了一套压力传感器温度响应特性校准装置,实现了在-50℃至100℃环境温度条件下,对绝压2~500 kPa范围内压力传感器校准,校准装置测量不确定度优于0.05%(k=2),为开展压力传感器温度响应特性研究奠定了基础。

基于播种单体限深臂压力和角度的播深智能控制系统

为了提高农作物播种深度的稳定性和一致性,进而提高农作物的产量,设计一套以限深臂对限深块的作用力和限深臂摆动角度为监测对象获取播深信息,以电动推杆为执行元件调节单体上下摆幅的基于力反馈式播深智能调节系统。通过对限深臂、四连杆处进行力学分析,确定了压力传感器和电动推杆的量程。针对电动推杆工作中存在误差的问题,采用Mamdani模糊算法建立智能调节模型,对电动推杆的控制进行优化。静态试验表明:在控制系统中添加Mamdani模糊控制算法,误差峰值的校正达到75.6%,播种深度的控制误差降低了60%。

色差对星敏感器成像模型参数影响分析与补偿

星敏感器在投入使用之前需要对其进行标定以获取准确的成像模型参数值来保证姿态测量精度。现有标定方法采用单一谱段光源模拟恒星成像未考虑恒星光谱特性,色差导致标定的模型参数值和真实值存在差异。为提高模型参数准确度,首先建立了光谱差异下星敏感器恒星成像模型,进一步分析了色差对不同光谱型恒星成像模型参数的影响。在此基础上,提出采用三个典型谱段模拟恒星成像,利用三谱段成像位置信息来推算不同光谱型恒星在星敏感器工作谱段范围内成像位置,以实现对任意光谱型恒星成像模型参数的补偿。实验结果表明:相对于现有利用单一谱段标定参数测量的星角距,该补偿方法测量的星角距均方根误差降低了40.81%,有效减小了色差对星矢量测量的影响。

施肥对TDR土壤水分传感器测量精度的影响研究

为明析施肥对时域反射法(TDR)土壤水分传感器测量精度的影响规律,并提出适宜的标定方法,以提高其测量精度。以TDR土壤水分传感器作为研究对象,考虑土壤质地、土壤含水率、施肥量3个因素,选取新疆棉花主产区喀什的壤质砂土、克拉玛依的粉质壤土、昌吉的粉砂质黏壤土,设5个土壤含水率水平,5个施肥水平,共计75个处理;以烘干法为基准,建立了TDR土壤水分传感器标定模型,并进行验证。结果表明:在不同土壤含水率条件下,TDR传感器误差随着含水率的增加整体呈增大的趋势。同一含水率时,壤质砂土条件下的TDR传感器误差随施肥量的增加整体呈现增大的趋势;粉质壤土条件下的TDR传感器误差随施肥量的增加呈先减小后急剧增大的趋势;粉砂质黏壤土条件下的TDR传感器误差随施肥量的增加呈先增大后减小再增大的趋势。建立了TDR土壤水分传感器输出值与施肥量、含水率之间的多元回归预测模型并采用Logistic模型进行了标定,壤质砂土、粉质壤土、粉砂质黏壤土试验条件下标定后的平均绝对误差分别为-0.18%、1.46%、0.01%,表明考虑施肥量及含水率的变化对TDR传感器检测精度的提高有积极作用。

基于末端触觉传感器的智能机器人压力补偿

末端触觉是智能机器人实现对外部环境做出直接反应的必需媒介。触觉传感器的弹性层易导致表面接触压力测量结果出现偏差,降低机械手的抓取力度的合理性。提出智能机器人末端触觉传感器压力误差补偿方法。建立触觉传感器三维力学模型,分析表面接触应力与弹性层之间的关系,得到传感器压力特征;计算弹性层的低通效应值,通过传感器测量值推理得到表面压力值,利用线性迭代反卷积算法对压力误差补偿。实验结果表明,研究方法应用下,压力误差补偿的均方误差接近于10-3,精度与理想效果更接近,上述方法获取的传感器对不同大小作用力的电学响应结果与实际数据具有较高一致性。

综采工作面液压支架测高传感器设计

针对综采工作面液压支架高度测量困难和可靠性、稳定性差等问题,设计了一种基于帕斯卡定律的液压支架测高传感器。该测高传感器内置一根细长液管,液管中充满甲基硅油,测高传感器两端安装压力传感器,通过测量密闭液管的两端压力,得到测高传感器两端位置的高度差。甲基硅油在环境温度变化时具有明显的热胀冷缩特性,会引起密闭空间内的压力急剧变化,影响测量精度,提出了一种补偿方法:采用波纹管存储一部分甲基硅油,利用波纹管自身的弹性补偿甲基硅油热胀冷缩造成的体积变化;并在软件中通过算法校准甲基硅油体积变化带来的密度变化,从而确保测高传感器的测量精度。试验结果表明:测高传感器可工作在0~40℃环境下,测量误差在4 cm以内。在薄煤层、中厚煤层综采工作面液压支架的现场应用结果表明:与人工测量结果相比,测高传感器的高度测量误差在5 cm以内,说明该传感器可靠性较高。

触觉传感器的高精度动静态标定技术研究

目的:提出了一种触觉传感器的高精度动静态标定方法和装置。方法:装置以STM32单片机为核心处理器,单片机接受上位机发送的指令,控制直线电机运动。力传感模块采集标定过程中的实时力值反馈到单片机,通过处理计算出误差,修正直线电机的位置,直到标定完成。最后计算不确定度。结果:实验结果表明,该装置可以在动态情况下对触觉传感1.000~5.000 N范围内的压向力进行标定。结论:该装置在标定触觉传感器压向力时,标定精度和准确度高,同时考虑到了动态力标定的因素,具有较高的实际应用价值。

PSI9216压力扫描阀并行自动校准方法研究

介绍了PSI9216压力扫描阀的结构和工作原理,为保证测量结果的准确性,制定了PSI9216压力扫描阀校准方案。计量标准采用标准模块可更换的高精度数字压力控制器,可实现压力扫描阀校准的能力覆盖,采用并行校准结构设计,可实现多台同量程压力扫描阀的同步校准,可有效保证校准工作的效率。通过校准软件的开发,可实现校准过程的完全控制,保证校准结果的准确性和可靠性。