Showing papers in "Chinese Journal of Sensors and Actuators in 2006"

Forest Fire Detection System Based on Wireless Sensor Network

Abstract: Wireless sensor network(WSN)is a new research field of information sciencesThis paper presents a forest fire detection system frame based on WSN and its implementation scheme,then discusses some key problems,which focuses on the forest fire forecast modeling,WSN nodes deployment,WSN nodes and forest fire positioning,wireless communication control protocol

A GaAs Pressure Sensor Based on Resonant Tunneling Diodes

Abstract: In order to break through the macroscopically physical limitation of the traditional mechanical-electrical effect, provide the theory, process and experimental references for the design of higher sensitivity, lower power consumption pressure sensor, a GaAs Pressure sensor based on resonant tunneling diodes (AlAs/In_xGa_ 1-x As/GaAs RTD) is designed and processed by the control hole technology firstly, and the process integration of RTD and micro-mechanical technology is implemented. The test results show that the linear sensitivity is up to 0.1 mV/kPa.

Segmentation Type Capacitance Sensor and Its Application

Abstract: During the crude oil produces in the oil field, measuring of the oil-water interface has been a key technology and difficult problem all the time. The author has designed a kind of new-type segmentation type capacitance sensor on the basis of the traditional capacitance sensor principle, which has well solved this difficult problem. Because of its high precision, simple principle and structure, and the cheap price, this sensor has very good application in prospect.

Development of High Accuracy Magnetic Electronic Compass

Abstract: The design of magnetic electronic compass is introduced.Using magnetoresistive sensor made by ourselves,a novel magnetic electronic compass has been developed.In the portion of signal conditioning circuit,AC amplifying technique is involved so that the error due to null and drift of magnetoresistive sensor is minimized.According to the characteristics of interference,8-position calibration method is adopted to realize auto-calibration.The maximum of azimuth error is less than 0.1° in the outdoor test.The results of experiment show that this magnetic electronic compass is of high accuracy.

Research on Routing Algorithm for Wireless Sensor Network

Abstract: Wireless sensor network (WSN),which is utilized in a broad foreground, is able to instantly monitor and collect various information of different objects in the network distributed area. The main techniques of WSN are to design an effective routing algorithm, which will advance the communication connectivity, decrease the energy dissipation and prolong the lifetime. Many typical routing algorithms are classified to be different types in this paper. The characteristics of different types are analyzed. Combining these characteristics, a routing algorithm which can adapt to a wider network scale is introduced, and improvement also is needed. Results of simulation prove the validity.

The Design of the Subwavelength Wire-Grid Polarizers Based on Rigorous Couple-Wave Theory

Abstract: According to the request of the sensitive wave band of 052-059μm of the bionic micro-nano navigation system, effects of different grating materials, grating shapes and grating parameters on the TM polarization transmission efficiency as well as the extinction ratio are analyzed by using the rigorous couple-wave theory,and the corresponding wire-grid polarizer is designed When it works at the normal incidence, difference between the designed grating and conventional wire-grid is that the former adds the magnesium fluoride between the fundus and the grating, and the TM polarization transmission efficiency and the extinction ratio are increased The TM polarization transmission efficiencies are more than 50 percentages and the extinction ratios are more than 170 when the incident wavelength is varied from 038 μm to 040 μm or from 050 μm to 076 μm, which meets the expectations for wide band, high TM polarization transmission efficiencies and high transmission extinction ratios

Research on the Application of the Time-Serial Analysis Based Kalman Filter in MEMS Gyroscope Random Drift Compensation

Abstract: The compensating method for MEMS gyroscope random drift error is discussed. First its drift error model is created by using the time-serial analysis, then the process of decreasing this drift error by making use of Kalman filter based on the above error model is expounded. The compensating results for the practical testing data of a MEMS gyroscope show, the drift error can be controlled effectively by the filtering method presented, and its application precision in practical system can be further proved.

Multi-Features Selection and Extraction of Structured Light Images of Vision Sensor for Seam Tracking

Abstract: According to various types of images features of welding work pieces joints in vision sensor for seam tracking in welding robot,a method of features selection and extraction for structured light images is proposed.Images are fragmented with adaptive thresholds,and the centerlines of laser stripes are extracted.By the characters of three typical joints:the groove joints,the butt joints and the left or right lap joints,the points of center gravity of grooves,turning points and the points of discontinuity of stripes are selected as features to be extracted respectively.Test results of images of different type joints testify the efficiency of the method.

Energy-Aware Hierarchical Clustering Algorithm for Wireless Sensor Networks

Abstract: In order to solve the problem of inappropriate cluster head election and excessive long transmission distance, EACT(Energy-Aware Cluster-Tree)algorithm is proposed to organize the cluster tree backbone network .Based on root tree and Maximal Weighted Independent Set, EACT utilizes periodical rotation of cluster heads to balance the energy consumed by nodes. Simulation results demonstrate that EACT would significantly increase the lifetime of the network. And the approach bears the characteristics of energy efficiency, and low complexity.

Experimental Study of Sense Characteristic Based on Metalized Package Fiber Bragg Grating

Abstract: An approach of metalized package for fiber Bragg grating has been proposed and then the temperature and strain sensing properities of the encapsulated FBG sensor has been experimentally studied on hot water and cantilever beam. The results indicate that the metalized encapsulating technique can improve the temperature sensing ability of metalized package FBG sensors to 23.357 pm/℃, which is 2~3 times as much as that of bare FBG sensors and strain sensing experiment obtain good symmetry, which correlative coefficients is 0.999 9.

Design and Fabrication of Low-Numerical-Aperture Amplitude-Photon Sieve

Abstract: It is difficult to use a traditional refractive lens to focus soft x rays, because of the strong absorption of solid materials in this spectral region. However, photon sieve, which is a novel diffractive optical element consisting of a large number of precisely positioned holes distributed over a flat surface, can be used to the focusing and imaging of soft x rays. Photon sieve can be used as a part of MOEMS to improve the efficiency and lower the cost because it is small in size, light in weight, repeatable in manufacture as well as it special optical performance. This new kind of MOEMS can be widely applied to martial, industrial, civilian and other fields. The imaging principle of photon sieve was introduced. The methods of design and fabrication of low-numerical-aperture amplitude-photon sieve were discussed, and the simulation results of photon sieve were presented, according to scalar diffraction theory. Laser-beam lithographic process was used to produce the photon sieve which feature size is 5 μm on a chrome-coated quarts plate. The imaging performance of the photon sieve was tested.

Survey on Intelligent Information Processing in Wireless Sensor Networks

Abstract: The Wiressless Sensor Network (WSN), which consists of a large number of micro sensor nodes, is mainly used to gather data information from the monitored environments. However, the strict constraints on individual sensor node's resource bring great challenges to the information processing of WSN. Consequently, simple and efficient algorithms must be taken. This paper gives an overview of the intelligent information processing approaches of WSN, which includes in-network aggregation, data compression, distributed database storage and query and so on. The principles and advantages/disadvantages of each approach are pointed out,and the key problems to be studied are pointed out here too.

Research of Water Content Measurement Based on Microwave Transmission

Abstract: A measurement system based on microwave transmission principle was designed for measuring medium or high water content of liquid/liquid two-phase flow in which water is one phase.Compare with the common sensors used in other measurement systems,the designed sensor in this system can decrease interference effect,and is more suitable to measure medium or high water content.According to the measured sample,the optimal measure frequency was selected to do experiments.Analyzing the experimental data got an empirical formula for measurement.The experimental results indicate that the system is effective for measuring water content of liquid/liquid two-phase flow.The measurement accuracy is higher than 5%.

Electrical Capacitance Tomography System Based on DSP

Abstract: To solve the bottleneck of imaging speed and the issuing of precision for analogue filter and analogue demodulation of electrical capacitance tomography, this thesis puts forward and designs a digitalized system of electrical capacitance tomography The designed system is based on the Digital Signal Processing and Field Programme Gate Array to provide a new digitalized system of electrical capacitance tomography , which includes the digital filting and the digital demodulating algorithm on the basis of the FPGA The results of theoretics analysis and experiment show that the design has the advantages of both the high data acquisition speed and the high noise rejection ability It can meet the needs for data acquisition system in electrical capacitance tomography very well and improve the precision of the imaging process

Development of Pulse Acquisition Device Based on Image

Abstract: According to principles of bionics, a new pulse acquisition is developed with a new method of pulse acquisition based on image. Under the different pressure of pulse diagnosis, the device can detect the pulse information of the surface of skin through high-resolution camera, which obtains multidimensional, overall information. It will be an ideal tool for objective study of TCM (Traditional Chinese Medicine), and especially suitable for the pulse image acquisition of TCM. The device has broad prospect of application to TCM.

Multisensor Target Recognition Based on the OWA Aggregation Operator

Abstract: The Ordered Weighted Averaging(OWA) Operator is briefly described, then it is used in the multisensor attribute information fusion Based on the OWA operator, a two-level attribute information fusion model is introduced According to the orness of the associated weighting vector, the fusion degree of the sensors is adjusted Finally, the target recognition example based on this fusion model shows that this method is efficient and correct

Research on Time Synchronization in Wireless Sensor Network

Abstract: Time synchronization is an important issue in multihop ad hoc wireless networks such as sensor networks Many applications of sensor networks need local clocks of sensor nodes to be synchronized, requiring various degrees of precision Some intrinsic properties of sensor networks, such as limited resources of energy, storage, computation, and bandwidth, combined with potentially high density of nodes make traditional synchronization methods unsuitable for these networks Hence, there has been an increasing research focus on designing synchronization algorithms specifically for sensor networks This article reviews the time synchronization problem and the need for synchronization in sensor networks, then presents the basic synchronization methods explicitly designed and proposed for sensor networks, finally compares and analyses these synchronization methods, and indicates the research directions in the future

Micro Milling of the Inertial Components with 3D structure

Abstract: Micro Milling technology is used in the manufacturing of the inertial MEMS components with 3D micro structures This kind of inertial MEMS components are made of high-performance elastic alloy with characteristic dimension of 10 μm~100 μm and machining accuracy of ±1 μm It also has strict requirement on the residual stress With the self-designed 3 axis micro milling machine, the optical cutting parameters are studied and the components are successfully manufactured With micro-bridge method, elastic modulus and residual stress are measured

Multisensor Target Identification Based on Mass Function of Statistical Evidence and D-S Evidence Theory

Abstract: Mass function is interpreted the precise degree of evidence and described as a basic probability assignment. In this paper, we discuss mass function of statistical evidence and D-S evidence theory , which is applied to multisensor target identification. A example is given. The results show that the method is propitious to realize target identification, so it takes on preferable practicability.

Improved Algorithm for Threshold De-Noising in Wavelet Transform Domain

Abstract: Based on Multiresolution analysis wavelet threshold de-noising method which put forward by DLDonoho and IMJohnston, a new bivariate threshold function is posed The de-noising method adopting the new threshold function gives better MSE performance and SNR gains than that of hard and soft thresholding methods However, the hard thresholding is best in preserving edges but worst in de-noising, and soft thrsholding is best in reducing noise but worst in preserving edges, this method incorporates the hard and soft thresholding to achieve a compromise between the two methods Numerical simulations show that this de-noising method is effective and excellent

Using 3-Axis Accelerometer ADXL330 to High Accuracy Pedometer

Abstract: During recent years, more and more portable devices, such as handset、MP3 and PMP, are calling for healthy and mobile features. Pedometer is an instrument that can measure human step and calculate consumed energy. Unlike traditional mechanical pedometer, a new kind of pedometer based on ADXL330 from Analog Device, is of high sensitivity, high accuracy (95%), high integration and low power consumption (3.3 mW), suitable for portable consumer electronic device. ADXL330 is 3 axis analog outputs, low g accelerometer, with 330 mV/g_n sensitivity.

Research on Compensating Error Model of Quartzose Flexible Accelerometer

Abstract: For the sake of insuring the precision of accelerometer in SINS, the static output characteristic of the CHJN-2A quartzose flexible accelerometer has been studied. The error origin of the accelerometer has been analysed via lots of static experiments repeated, and the mathematic model of compensating error is achieved. It has been shown that the static output characteristic of the accelerometer is repeated. The precision of the SINS can be improved by error compensation of accelerometers.

The development of Vortex Flowmeter

Abstract: The growth rate of vortex flowmeter is high. At present, vortex flowmeter is applied extensively to the measurement of pipe flow rate, and have become one of the flowmeters available for general use. However, vortex flowmeter is developing flowmeter. There are still some limits in understanding of fundamental flow physics and experience of practical application. In order to solve these problems, many efforts have been done to the vortex flowmeter, and progresses have been achieved. The development of vortex flowmeter is discussed and reviewed in these aspects: vortex separating, vortex shedder shape, vortex shedding signal measurement and processing. The difficulty in research and future trends of vortex flowmeter are also discussed. A new mass flow rate measurement method using vortex shedding principle is proposed.

Application of the Wavelet Transformation in the MEMS Gyroscope De-Noise

Abstract: The wavelet theory was introduced. The residual signal from the gyroscope was decomposed by the different scale biorthogonal stationary wavelet base. The result showed that the Bior1.1 wavelet had the better performance. The coefficients of the decomposing filter and the rebuilding filter were also very simple. It proved that the wavelet transformation was feasible in the de-noising of the gyroscope drifting signal.

Automatic Recognition for the Position and Pose of Parts Based on Image Moment Invariants and Neural Network

Abstract: The automatic recognition for the position and pose of measured part is a key technology in the inspection system of intelligent coordinate measuring machineSome virtual images of measured part are formed according to each possible placed modeAnd the actual image is captured by the CCD cameraThe theory of image moment invariants is applied to image matchingThe BP neural network is trained by the moment invariants of virtual images and the corresponding patternsUsing the trained neural network as classifier,the pose of measured part is recognized by the moment invariants of captured imageAt the same time,the position and orientation of part figure in the image are calculated by the moment of captured imageThrough the coordinate transforming,the position and orientation of measured part in the machine reference frame are gainedThe experimental result shows that the method of automatic recognition for the position and pose is intelligent and efficient

The Research on Multi-Sensor Information Fusion with Out-Of-Sequence Measurement

Abstract: In a multiple sensor tracking system, out-of-sequence measurement(OOSM) always occurs due to communication delays. The system needs to solve with the OOSMS in order to improve the precision. Updating the state estimation is one method of dealing with such problems. It presents one method of solving with OOSMS in the multi-sensor information fusion, and the simulation shows that the algorithm can improve the estimation effectively.

One Novel MEMS Integrated Design Tool with Maximal Six Design Flows

Abstract: The design flow in current commercial MEMS CAD software is usually unified in either top-down or bottom-up design method, which can not satisfy the various design requirements for many different MEMS devices by now. This paper established one MEMS CAD prototype system with total six design flows, by far the number of which is the maximal under the current popular MEMS CAD structure. The design tool includes three levels, i.e. system, device and process level, which took the netlist, solid model and layout as the design data flow inlet and outlet for each level separately. The algorithm and program were designed to realize the data auto transmission between every two levels, which built up the foundation of the total six design flows. Especially the design flow from the system to device level and finally to the process level was firstly realized. It realized the conceptive synthesis from the MEMS device’s function to their geometry, which could greatly reduce the iteration of design. The design examples showed that the designers could choose proper design flows for specific devices with this tool, thus design efficiency was improved.

Development of Simulation Environment WSNSim for Wireless Sensor Networks

Abstract: It is necessary to develop simulation environment to evaluate the performance of Wireless Sensor Networks (WSNs), especially for the large scale WSNs. Drawbacks of current simulators are pointed out, and a new simulation environment WSNSim is designed and developed based on .Net framework from aspects of architecture, application scenes, simulation flow. WSNSim adopts experimented energy model and component based approach, which can detect condition of environment, process sporadic event and track mobile target. The effectiveness of improved protocol SEMAC is validated under the WSNSim environment.

Application of C_0 Complexity Measure in Detecting Speech

Abstract: This paper proposed a new speech detection method based on complexity measures It has nonlinear properties, comparing with those generally researched methods, including short-time energy, ZCR, frequency-entropy, LPCC and MFCC Through the result of a number of experiments, we have found that C_0 complexity can be a valid feature to make speech/non-speech decision under dynamical noise situation This new method will improve the accuracy of isolate-word speech recognition, and can also decrease the computations and complexity of speech process

Research on Ranging Performance of Laser Scanner in the Navigation of Mobile Robot

Abstract: Range detection is a crucial problem for the navigation of mobile robot. The operation principle of 2D laser scanner LMS291 is introduced simply, which is based on time of flight. Then, its error factors of ranging performance are analyzed. With the statistic analysis of data alignment, ranging accuracy of laser scanner under the influence of various target surface property is studied. At the same time, the angular resolution is determinated by the measuring method of mixed pixel and the error model is built by the experiments on ranging performance of laser scanner. The conclusions can provide the support for obstacles detection, environment map and self-localization in the navigation of mobile robot under complex and unstructured environment.