In order to solve the problem that traditional wafer positioning is easily affected by lightness,noise and other fac-tors and consume a lot of resources,the wafer detection algorithm YOLOv5s-wafer was constructed.The wafer detection dataset was constructed firstly,the lightweight network GhostNetv2 was used as the backbone feature extraction network to reduce the amount of model parameters.Then the CA attention mechanism was introduced into the feature fusion network to enhance feature extraction capabilities.Finally,EIOU was used as positioning loss function to improve the wafer detection accuracy.The experi-mental results show that the detection algorithm average accuracy is 99.3%,the parameter number is 4.637×106,which achieves an ideal balance between the detection performance and the lightweight of the algorithm.
针对变电设备智能物联监测中的分布式智能感知节点微型化设计需求,设计了一种新型的超声局部放电测量转换电路.使用高集成度仪表放大电路对高阻抗的超声局部放电传感器输出信号进行了低阻抗变换和固定增益放大,设计通带为 20～300 kHz的宽带滤波电路以适应变电设备上带宽不同的传感器,最后通过增益可调仪表放大电路适应不同灵敏度的传感器输出信号.电路能同时连接2 个超声局部放电传感器并对其测量信号进行转换,电路尺寸为83 mm×50 mm×15.5 mm.设计了相应的电路性能测试实验并给出了其在智能物联系统中的应用方法.实验结果表明:电路各级增益误差在整个通带频段内低于1%,1000 倍增益条件下的输出端噪声RMS值不超过10 mV.
针对MEMS压阻式压力传感器微型化发展过程中精度难以保证的问题,通过有限元仿真分析方法,研究固支结构、封装约束方法等变量对压力传感器输出的影响.结果表明,固支结构的引入会导致压敏电阻所处路径出现24.93%的应力偏差,不同封装方法会使路径上产生0.54%～2.42%的应力偏差.当固支结构宽度与压力敏感薄膜膜厚的比例大于 3 ∶ 1 时,压敏电阻所处位置应力积分均值稳定.结果表明,固支结构的约束方法、结构宽度均会对压力传感器的输出产生重要影响,合理设计固定约束结构可为压力传感器的微型化高性能设计提供保障.
In view of the influence of camera imaging deviation caused by plane refraction on visual measurement of the glass protective cover of explosion proof camera,a camera model under non-parallel plane refraction was derived,and on this basis,a correction method of refraction distortion based on dynamic virtual focal length was proposed,which effectively solved the problem that the refraction distortion was difficult to correct when the camera optical axis and the normal vector of refraction surface were not parallel.The experimental results show that the root mean square error of the corrected image deviation decreases by 68.69%and 72.82%,respectively,and the relative error of the corrected measurement is less than 0.5%.The positioning accuracy and measurement accuracy of the camera are obviously improved after correction.
In order to solve the automatic feeding problem of a series of non-standard screws,a screw flexible grasping system based on machine vision was proposed.Firstly,the Eye-to-hand visual positioning and grasping system was designed,and the ac-quired images were identified by image preprocessing such as binarization and particle analysis.Secondly,for the screw target,a series of circular characteristic parameters of the screw center direction were obtained by fitting the circle operation,and the cen-ter line was obtained by fitting the least square method,furthermore,pose parameters of grasping point and angle of the screw were solved.Finally,the ROI region conforming to the grasping characteristics of the claw was designed with the grasping point as the center to judge the grasping.The upper computer sent the pose information to the controller,guided the robot to move to the corre-sponding position,and completed the grasping of the screw workpiece through the end claw.Through the experimental verifica-tion,the positioning accuracy of the system is 99.5%.
The wind tunnel balance is the key force measuring equipment for wind tunnel test of aircraft model.In recent years,with the increase of aircraft model design complexity and flow field velocity,the requirements for the volume,temperature sensitivity and dynamic characteristics of the balance are getting higher and higher.In order to improve the dynamic performance of the balance and reduce its size,this paper proposed a piezoelectric six-dimensional force measurement method for the charge collection of the quartz wafer partition area.Aiming at the aerodynamic heat effect of high-speed flow field in wind tunnel,differ-ent balance materials were selected for thermodynamic simulation analysis.In order to improve the stiffness of the balance,the structural dimensions of the balance components were parameterized.Finally,the static and dynamic calibration and temperature sensitivity experiments of the piezoelectric rod balance were carried out.The results show that the nonlinear error of the balance does not exceed 1.31%,the repeatability error is less than 1%,the natural frequency is higher than 2 700 Hz,and the relative change of temperature influence is 0.5%,which meets the test requirements.
Signals in the 70 MHz to 6 GHz band are widely used in aviation,satellite and other communication scenarios.It is of great significance for the generation,direct acquisition and playback verification of the above signals,such as receiving and playback of RF signals in complex electromagnetic environment,transmitting RF signals in analog channel environment and tes-ting communication system functions.Considering the versatility and flexibility,a data acquisition and playback system based on FPGA+AD9361 was designed.The AD9361 can be configured via MicroBlaze to switch RF signal parameters.A signal source was generated by the host computer and delivered to the DA terminal through the PCIe bus.It can be used as a vector signal source.The collected data was uploaded to the upper computer for storage through the PCIe bus,and then sent to the transmitter of the AD9361 for playback,realizing the signal collection,storage and playback function.Taking monophonic signal and QPSK signal as examples,through the closed-loop test and analysis of their spectrum,the function of RF signal acquisition,storage and playback and transmitting RF signal source data is verified.
In this study,a set of AC switch machine signal acquisition board was developed based on embedded technology based on Q/CR442-2020"Technical Conditions of Railway Signal Centralized Monitoring System".The acquisition board used the true RMS algorithm to collect and calculate the voltage and current,and measured the active power of the three-phase action power supply by the improved two-table method,and carried out the isolation filter design of the circuit,so that the data collection was more accurate and reliable.Through the optimization algorithm to realize fast sampling data processing,the sampling frequen-cy was improved and the power consumption of equipment was reduced.Finally,the reliability,feasibility and availability of the acquisition board were proved through the analysis of test results in laboratory and field.The acquisition board has the advantages of high cost performance,low power consumption,fast acquisition speed,high reliability and so on.Besides,the expansion port is reserved for the electrical personnel to set fault monitoring points by electrical personnel,so it has broad development space.
By analyzing the advantages and disadvantages of existing spatial straightness measurement methods and the cur-rent situation and demand of enterprises for bar straightness detection,a rotating straightness detection and bending angle positio-ning method based on composite displacement was proposed.By studying the spatial straightness,circular runout,and full runout isomorphic error relationships,the spiral extraction method was used as the measurement point extraction method,and the two-endpoint connection method was utilized as the straightness evaluation method.The laser displacement sensor collected the dis-placement change information along the axial movement while rotating the bar,and the mathematical model of the displacement change information and straightness was established to judge the straightness error of the bar stock.Moreover,the bending angle positioning was realized according to the relationship between the displacement change information and the rotation stroke.Based on the above methods,a set of straightness detection and bending angle positioning device was designed and developed.The meas-urement accuracy and error analysis were carried out by experimental test,the results show that the accuracy,repeatability and bending angle positioning accuracy of the system meet the actual needs.
To attain highly sensitive low refractive index in the intermediate infrared region,a novel structure with dual open-ring channels was designed on photonic crystal fiber and the sensor was established on surface plasmon resonance effect.The de-signed PCF-SPR sensor was simulated by COMSOL finite element method.The results demonstrates that the sensor performed a significant detectability for low RI sensing,maximum wavelength sensitivity of the proposed sensor reaches to 10 300 nm/RIU in the RI range of 1.23～1.29,and maximum theoretical resolution is 9.71×10-6 RIU.
A piecewise polynomial fitting method based on least square method was proposed to calibrate the angular error of circular grating caused by manufacturing process and installation error.By designing the interval growth strategy,the whole fitting interval was segmented adaptively under the condition of limiting the maximum fitting error of each fitting point,and different or-der polynomials were adopted for fitting on different fitting intervals.The angle measurement error of a rotary's grating was col-lected by experiment,and the fitting method proposed in this paper was verified by experiment.The results show that this fitting method has the advantages of higher fitting accuracy,simple fitting process,and easy implementation of software and hardware.
In response to the demand for real-time monitoring of the conductivity of electric vehicle battery coolant,this paper proposed a conductivity transmitter for low conductivity battery coolant in new energy vehicles.The conductivity sensor in this conductivity transmitter adopted an integrated structure based on silicon based interdigital microelectrodes and Pt resistors,which can simultaneously achieve conductivity detection and temperature sensing,greatly reducing the volume of sensitive components.Using high-performance embedded processor chips as the control core of the sensor,combined with peripheral detection circuits to collect and process temperature and conductivity data,and segmented compensation algorithms were applied to achieve tempera-ture compensation for the battery coolant conductivity in the large temperature range of-20℃to 90℃.Through the actual test,the error of the designed conductivity sensor is less than±1.5%in the range of 0～20 μS/cm,which meets the measurement ac-curacy requirements of the new energy vehicle battery coolant.Therefore,the conductivity transmitter proposed in this paper has a strong competitiveness in the measurement of battery coolant conductivity.
The magneto sensitive elastomer(MSE)is a magnetically sensitive material with excellent magnetic response characteristics,which generates a magnetic field-induced normal force perpendicular to its surface under the action of a magnetic field,and combined with the direct piezoelectric effect of polyvinylidene fluoride(PVDF),a sensor combining the two character-istics was proposed for rotational speed detection.A composite structure consisting of MSE and PVDF piezoelectric unit was de-signed in the sensitive unit to sense the magnetic field excitation through the composite structure for rotational speed detection,and the detection mechanism was analyzed at the microscopic and macroscopic levels.The relationship between magnetic field-in-duced normal force and magnetic field,the dynamic deformation response of PVDF and the output characteristics of the sensor were established by a self-built test system.The results show that the sensitive unit with the composite structure as the core exhib-its a stable voltage peak response to the magnetic field excitation of the test speed,and can achieve accurate detection of medium and high speeds.
In response to the problems of high labor intensity,low efficiency,and high danger in traditional manual insulator replacement operations,a live insulator replacement robot with specific claws was designed.It consists of two parts,including an execution device for tower operations and a remote control device for personnel below the tower.Firstly,the principle of replacing insulators was analyzed,the action process of robot replacing insulators was planned,and the overall structure of the robot was de-signed to improve the effect of insulator replacement and reduce action errors.Secondly,a robot remote control hardware and soft-ware system based on UCOS and QT was developed,which enables operators to remotely and real-time monitor the robot.Finally,a functional testing platform was established for robot thrust and insulator replacement capability experiments,and pilot experi-ments were conducted on actual lines.The experimental results show that when the motor speed is set to 50%～60%,the robot can complete the insulator replacement process completely.Compared with traditional manual operations,the completion time is rela-tively shortened by 18 minutes,and the efficiency is improved by 42.8%.
In modulation transfer spectroscopy frequency stabilization(MTS)system,temperature fluctuation will affect the stability of laser frequency.A multi-point temperature measurement system was designed.The system used FPGA as the core,and the bridge circuit was excited by a reference voltage source to convert a three-wire PT1000 temperature change into a voltage change.The converter voltage was sampled by a synchronous sampling ADC,which was converted into real-time display and stored temperature in LabVIEW.The anti-RFI filter in signal conditioning circuit and mean filter in FPGA can reduce noise inter-ference and improve temperature measurement accuracy.Experimental results show that the system has satisfactory linearity,high precision and good repeatability.It can monitor and store temperature at 10℃to 80℃.After using segmented linear fitting,the temperature measurement error does not exceed 0.02℃,which can meet experimental requirements.
In motor vector control,stator current can only be generated through a complete closed loop control.In order to easily verify the correctness of AN9238 sampling,a simulated motor voltage signal in loop testing system was designed considering accuracy,universality,and portability.The system used FPGA as the main controller,with FPGA,upper computer,and DAC mod-ules as the main components for simulating the two-phase voltage output of the motor,and AN9238 module was used as the data collection and verification part.The overall design of the system was elaborated in the article,and the correctness of simulating the two-phase voltage output of the motor and data acquisition was verified.Compared with the expected set voltage of the system,the experimental results show that the system can customize any voltage within the output voltage range and the accuracy of the AN9238 acquisition module.The overall design met the actual engineering requirements.
Spin-exchange-relaxation-free(SERF)atomic magnetometers are the most sensitive magnetic field sensors,which have a wide application prospect.Due to the effect of the geomagnetic environment and residual magnetism of internal components for compact SERF atomic magnetometers,it is necessary to compensate the residual magnetism near zero(＜1 nT)to achieve high sensitive measurement.In this paper,a triaxial static magnetic field active compensation circuit for single-beam compact SERF a-tomic magnetometer based on the field programmable gate array(FPGA)was designed.By applying DC scanning magnetic fields to the three-axis coils of the atomic magnetometer,-60 nT to 60 nT three-axis magnetic field synchronous compensation was real-ized quickly and accurately.The average compensation accuracy can reach 0.12 nT and 0.25 nT in the measuring directions re-spectively and 0.36 nT in the pump light direction,which meet the requirement of high sensitive measurement of compact SERF atomic magnetometer.
Under outdoor inspection environments,the images captured by inspection robots were easily affected by various factors,resulting in low accuracy and poor robustness of pointer meter recognition.To address this issue,a pointer meter recogni-tion algorithm based on improved PSPNet was proposed.Firstly,YOLOv5 was utilized to identify the meter area.Then improved PSPNet was utilized to extract the pointer and scale area.After perspective transformation,the center-line of pointer was extrac-ted.Finally,the meter reading was calculated via angle method.The experimental results show that the average relative error of pointer meter reading is 1.28%and the average citation error is 0.68%under various complex outdoor environments.The average processing time of each picture is 1.28 seconds.It means our method is of great accuracy and stability,providing an effective pointer meter recognition algorithm for outdoor inspection robots.
In view of the problems that the traditional fluxgate sensor used in downhole smart drilling project is not resistant to high temperature and its size can not meet the narrow space of the well,a high-performance digital fluxgate sensor was designed to work in the high temperature environment of 175℃.The sensor was designed based on the second harmonic method,using SM320F28335GBS as the main control chip,coordinating the control of the excitation circuit,sensing circuit,feedback circuit and temperature data acquisition circuit,and the joint fluxgate probe realized the acquisition and processing of magnetic field signals in high temperature environment.Experimental test results show that the high-temperature fluxgate sensor range is of±60 000 nT,resolution is of 3 nT,linearity is of 0.03%,and high-performance fluxgate magnetic measurement data correlation coefficient is of 0.927,magnetic measurement data in the 175℃high-temperature environment verifies the digital fluxgate prototype can be used for high-temperature environment of the magnetic field measurement.
In order to meet the needs of real-time collection and transmission of massive data in biological behavior research and bionic behavior research,a multi-channel data acquisition system based on STM32 and LabVIEW was built.The system se-lected four ADS8528 analog-to-digital conversion chips to expand the number of STM32 acquisition channels to achieve synchro-nous acquisition of multiple signals,and uploaded the collected data to the upper computer through the wireless transmission mod-ule.The upper computer was designed with LabVIEW graphical programming language,and received the data collected by the lower computer through UDP communication protocol,and analyzed and processed the data.Through experimental verification,the data acquisition system can achieve single-channel 630 kSPS,32-channel 106 kSPS conversion rate,analog-to-digital conversion error is within 0.3%,wireless network transmission function is normal,and can meet the use requirements.
