Chinese Version Light学术出版中心
Latest Issue
Issue 6 ， 2016
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Optimization design of optical fiber sensors based on strain transfer theory
Abstract：In view of action mechanism of sensor applications, the fiber optic sensors commonly used in engineering were classified depending on the modes of transfer deformation.The relationship between strain transfer coefficient and measurement tolerance was established based on the strain transfer theory. Thereby, the optimal values of the sensor to meet accuracy requirements of engineering tests can be obtained for the optimization of control equations, and more specific optimization design methods and priority design specifications of various types of sensors were given. The research indicates that: optimal design method based on strain transfer theory is more applicable to the fiber optic sensors whose transfer deformation relies on interfacial shear stress, and its priority design specifications are sequentially as follows: bonded (sensing) length, interlayer adhesion strength, elastic modulus and radius of protective layer, adhesive layer thickness; optimization design of end-diameter expanding sensor is not dependent on the strain transfer theory because the strain transfer coefficient can be accurately and conveniently obtained through calibration tests without obvious priority design specifications. With full consideration given to the actual status of sensor application in engineering, by taking the test accuracy as the core, this article conducts a more comprehensive and systematic analysis on optical fiber sensor from the perspective of mechanical action mechanism was conducted.This research proves able to more scientifically guide the application design and calibration test of optical fiber sensors in engineering.Keywords：optical fiber sensor;strain transfer theory;optimization design;priority design specifications- 54
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Published：2020-08-13 -
Wavelength calibration algorithm for echelle spectrograph
Abstract：An automatic algorithm to rapidly process the spectrogram of the echelle grating spectrometer was proposed based on the linear fitting method of centroid extraction, solving the problem that the echelle grating spectrometer can not calibrate wavelength of incident rays through the two-dimensional spectrogram which was formed by cross dispersion. The background correction method is adopted to process the spectrogram based on the distribution characteristics of background light of the spectrogram of echelle grating spectrometer, thereby the calculation efficiency of the optical spot extraction algorithm of the follow-up spectrogram of echelle grating spectrometer was improved. The curve fitting center positioning algorithm based on centroid was employed to improve the extraction precision of the optical spot position to the sub-pixel magnitude. The auto-match model of the theoretical spectrogram of echelle grating spectrometer and the actual two-dimensional spectrogram were established and the method of interpolation was adopted to calculate the wavelength at the coordinate position, which is not listed in the recovery model of the spectrogram based on the linear dispersion characteristics of optical grating. The result shows that: the processing time of the whole spectrogram by this algorithm does not exceed 3 s and the wavelength extraction precision is up to 10-2 nm, not only achieving the automatic wavelength extraction of the echelle grating spectrometer but also improving the wavelength extraction precision.Keywords：echelle grating spectrometer;two-dimensional spectrogram;wavelength extraction;centroid extraction;auto-match- 50
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Published：2020-08-13 -
Three-dimensional attitude information obtained by the skylight polarization pattern
Abstract：The two-dimensional direction information provided by the current polarized skylight navigation method can not meet the actual needs of the navigation, therefore, a method for obtaining 3D pose information by using atmospheric polarization modes was researched. The sun was selected as the spatial point with the salient feature, then the sun spatial position information of the carrier was calculated under two different states by using atmospheric polarization mode information, and thereby 3D pose information of the carrier was obtained through the establishment of attitude transformation matrix. Finally the error distributions in obtaining solar spatial position information under different weathers, different solar spatial locations, different bands and the conditions of the sky being partially obscured were investigated theoretically and experimentally. The result show that the errors of elevation and azimuth angles are 1.50° and 2.10° respectively in the blue band in aerosols, and the average errors of the elevation and azimuth angles are 0.91°and 1.97° respectively in the field of views being obscured by trees. It is indicated that the sun spatial position can be effectively obtained under different circumstances by the proposed method, which can meet the need for 3D pose information of the carrier in actual navigations.Keywords：polarization optics;polarized skylight navigation;atmospheric polarization mode;solar spatial position;3D pose information- 98
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Published：2020-08-13 -
Beam deflection scanning for laser confocal microscopy
Abstract：To improve the scanning speed of the laser confocal system, a field synchronous scanning method was proposed. The laser confocal microscopy system was implemented with a GVS002 two-dimensional galvanometer from the THORLABS Company. The scanning waveforms of galvanometer were calculated in accordance with the parameters and scanning range of the optical system. The synchronous scanning waveform was output from a PCIe6353 multi-functional data acquisition card of NI Company. Meanwhile, it collected the optical intensity signals at the pinhole at the focus of the confocal microscopy system and scans a 256×256 image and a 512×512 image successively, recording the scanning images and imaging time; then, the scanning waveforms were output in field synchronization under the same hardware structures, recording the scanning images and imaging time. The experimental results show that the speed of the 256×256 image scanning through field synchronization can be increased by 10 times and the speed of the 512×512 image scanning can be increased by 5 times. In addition the field synchronous scanning can meet such requirements of the confocal microscopy imaging as the clearness and strong capacity of resisting disturbance. Compared with the line synchronization scanning, the field synchronous scanning can eliminate the retention time during the line to line conversion and significantly improve the scanning speed without changing the hardware.Keywords：Confocal microscopy;Two-dimensional galvanometer;Field synchronization;Board card control- 47
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Published：2020-08-13 -
Evaluation on noninvasive blood components measurement based on photolepthysmography
Abstract：To evaluate the precision level of Photolepthysmography(PPG) in detection of the main components of human blood, the formula for the limit resolution concentration of material components measurement was given based on the Lambert-Beer's Law and simplified measurement model of PPG. Through the evaluation of three elements-Signal-to-Noise Ratio(SNR) of light intensity, optical path and the molar extinction coefficient of the blood components during human measurements, the theoretical limit resolution concentrations of the pulse oximeter signal method for hemoglobin, albumin and blood glucose were obtained. The evaluation result shows that the limit resolution concentration levels of hemoglobin, albumin and blood glucose which can be measured through PPG are respectively 100 mg/dL, 5000 mg/dL and 10 000 mg/dL. The comparison of the evaluation result with the detection precision needed on clinic at the present stage indicates that the PPG can meet the demands for the non-invasive detection of hemoglobin.Keywords：photolepthysmography;human non-invasive component detection;hemoglobin;albumin;blood glucose- 52
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Published：2020-08-13 -
Performance testing of a desk-top 97-element adaptive optical system
Abstract：A set of performance test system of the desktop adaptive optical system was established to verify the correction capability of a 97-element adaptive optical system. The test system mainly consisted of such components as the light source, fast steering mirror, deformable mirror, Shack-Hartmann wave-front sensor, fast wave-front processor and disturbance phase screen. The data of the interferometer and Shack-Hartmann wave-front sensor were employed to control the deformable mirror for the flattening correction of optical path and the static correction precision of the system was obtained. Then, the correction capability of the precision tracking system was tested. Finally, the disturbance phase screen was use to simulate different atmospheric disturbance conditions and the dynamic correction capability of the adaptive optical system was tested under different degrees of target brightness with the Strehl Ratio (SR) of the imaging camera image being the index. The results show that: the RMS of the static wave aberration correction precision of the 97-element adaptive optical system is approximate λ/20; the error suppression bandwidths of the precision tracking system under two control modes can respectively reach 15 Hz and 39 Hz; when the system is under the strong turbulence, the imaging resolution after dynamic correction is basically superior to three times of diffraction limit. It indicates that the 97-element adaptive optical system can effectively correct the aberration and improve the imaging resolution.Keywords：adaptive optics;performance test;dynamic correction;Precision tracking;deformable mirror;Strehl Ratio;phase screen- 112
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Published：2020-08-13 -
Novel integrated solar water heater with compound parabolic and involute concentrator
Abstract：A novel integrated solar water heater with compound parabolic and involute concentrator with high heat-collecting efficiency, low heat loss and low cost was introduced, aiming at such disadvantages of all-glass evacuated tubular and flat plate solar water heater as complex system, high cost and maintenance inconvenience and such problems of the conventional integral solar water heater as low heat-collecting efficiency and serious heat loss. The optimization design was done for the concentrator of the compound parabolic, involute and the combination of compound parabolic and involute.Then the heat collector tank with selective absorbing coating which is matched with the concentrator system was designed. Finally, the integral solar water heater system was set up and the test for the heat collecting performance was performed. The results show that when the average solar irradiation intensity is 800 W/m2 and the average temperature of the ambient environment is about 21 ℃, the integral solar water heater can heat 40 L water from 21 ℃ to 62.20 ℃ with the cut length of efficiency of the system is 0.63 and the heat loss coefficient is 10.40 W/(m2·℃). However, the cut length of efficiency of the traditional integral solar water heater with black polyethylene plastic bag is 0.31 and the heat loss coefficient is 13.32 W/(m2·℃), compared to which, the proposed system has obvious advantage on heat collecting efficiency and thermal insulation properties.Therefore it can fully meet the demands of people for hot water for daily life with good market prospect.Keywords：solor energy;compound parabolic concentrator;involute;integral solar water heater;instantaneous efficiency;selective absorbing coating- 50
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Published：2020-08-13 -
Large-diameter membrane Fresnel diffraction elements for space telescope
Abstract：In order to meet requirements of large diameter and light-weighting diffraction elements for space diffraction imaging system, the polyimide (PI) membrane Fresnel diffraction elements with the diameter of 400 mm were designed and manufactured. With ultraviolet lithography, ion beam etching and other microfabrication methods, diffraction patterns on quartz substrate were made and then reproduced onto PI membrane, thereby obtaining the Fresnel diffraction type membrane elements. The change rule of thermal stress during the membrane reproduction process and the methods for reducing thermal stress were researched by Finite Element Method (FEM). The influence factors of the membrane diffraction efficiency, and impact of membrane production error and temperature change on membrane imaging were analysed. Finally, the separation of large-diameter membrane and substrate was realized, and the uniformity of membrane diffraction efficiency was improved by local oxygen plasma bombardment. By testing, the thickness of membrane Fresnel diffraction element is 20 μm, and the average value of actual diffraction efficiency is 33.14% when wavelength is 633 nm, reaching 81.83% of the theoretical efficiency, and Root Mean Square (RMS) of diffraction efficiency is 0.01. The experimental results show that large diameter and high diffraction efficiency membrane Fresnel diffraction elements can be manufactured by ultraviolet lithography, ion beam etching and membrane reproduction.Keywords：diffraction optics;large diameter diffraction elements;pI membrane;diffraction efficiency;space telescope- 84
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Published：2020-08-13 -
Detection of respiratory rate using pulse wave on near infrared wearable devices
Abstract：Aiming at the problems of the inaccuracy and insufficient instantaneity in estimation of respiratory rate from photoplethysmography(PPG) on the wearable devices, an Adaptive Signal Decomposition(ASD) algorithm based on time-frequency spectra was put forward. This algorithm adopted the instantaneous center frequency to obtain the pulse wave time-frequency spectra and instant heart rate estimated values, and the breath signal ingredient was extracted through coherent demodulation on the pulse signals, then the respiration signals can be used to detect the respiratory rate. The result indicates that in comparison with the conventional Continuous Wavelet Transform(CWT), the respiratory rate calculation time of ASD algorithm has been increased by 84.68%. The variance analyses of the median error and the interquartile range error indicate that the ASD algorithm has the better calculation accuracy than the CWT algorithm and the autoregression model algorithm, with the median error means compared to which increased by 96.001% and 97.978% respectively and the interquartile range error means increased by 75.014% and 52.732% respectively.Keywords：pulse oximeter signal;respiration rate;wearable equipment;Near-infrared;time-frequency spectrum- 57
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Published：2020-08-13 -
Effect of adhesive viscoelasticity on strain transfer mechanism of bonded FBG
Abstract：The effect law of adhesive visco-elasticity on bonded FBG strain transfer was studied in consideration of the effect of adhesive creep on FBG strain transfer under static load during the application of FBG sensor to machine tool strain monitoring. The bonded FBG strain transfer model was re-established for the linear visco-elastic material based on the bonding layer which is simplified as a three-parameter solid model, thus the instant and quasi-static strain transfer relation of the bonded FBG sensor was obtained. Then, the effects of the bonding length, width and height and thickness of interlayer on the instant and quasi-static strain transfer were analyzed through theory and experiment. The experimental results show that: the adhesive creep will lead to the variation of FBG strain with time under the constant stress action; when the bonding length is above 30 mm, the FBG strain transfer ratio change with time is about 4%; when the bonding length is 15 mm, the strain transfer ratio change is approximate 7%. The analysis implies that the appropriate increase of bonding length and decrease of the thickness of bonding interlayer can reduce the effect of adhesive creep on strain transfer. This conclusion has guiding significance for the high-precision measurement based on bonded FBG.Keywords：fiber optical sensor;fiber Bragg grating (FBG);strain monitoring;linear visco-elasticity;creep;strain transfer ratio- 78
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Published：2020-08-13 -
Self-calibration of terrestrial laser scanner based on stochastic inner constraint information of estimated parameters
Abstract：In terms of high correlation in self-calibration of ground pulse laser scanner, a unified method for self-calibration of pulse laser scanner has been put forward based on the error model of the total station. In this method, it is originally assumed that the calibration parameter of the laser scanner is similar to the system error of the total station, and the objective of reducing the parameter correlation and improving the reliability of parameter estimation is attained by means of introducing relevant randomized information of the estimation parameter and selecting appropriate network configuration. Through the adjustment method, the estimation parameter is endowed with weight information. By regarding each parameter as the observed value in the least squares adjustment, the higher the weight is, the lower the parameter correlation will be. Finally, self-calibration of Leica scan station of the pulse laser scanner is carried out through this method. It is showed in this test that this method can help to achieve high-precision parameter estimation and realize low parameter correlation, which makes for the application of randomized constraint adjustment. Major system error is the zero error of laser range finder and the index error of vertical circle, and to achieve a reliable estimation of the zero error, location of the scanner should be confirmed with a precision of about 1 mm.Keywords：3D measurement;Terrestrial Laser Scanner(TLS);self-calibration;error model;correlation- 47
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Published：2020-08-13
Modern Applied Optics
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Analysis on wave mode of flexible surface acoustic wave devices
Abstract：ZnO piezoelectric films were deposited on polyimide substrates by reactive magnetron sputtering method, and flexible Surface Acoustic Wave( SAW) devices were prepared based on the ZnO piezoelectric films. The flexible SAW devices show excellent resonant characteristics and two wave modes, mode 0 and mode 1. The resonant frequencies of the SAW devices with a ZnO layer by thickness of 4 m are 34.4 MHz and 158.5 MHz for the mode 0 and mode 1, and corresponding acoustic phase velocities are 1 100.8 m/s and 5 072 m/s, respectively. The Mode 0 is Rayleigh wave, while the Mode 1 is a new high frequency mode. The ZnO piezoelectric films with different thicknesses were deposited for preparing the SAW devices, and the effects of ZnO film thicknesses on the SAW devices and the new mode were analyzed by Finite Element Method. The results show that the new high frequency mode is not the Sezawa wave produced on the traditional hard substrate but is a S0 Lamb wave with a substrate. Moreover, the Comsol was used to simulate and analyze the vibration and surface displacement of the Mode 1 with PI or without PI substrates and the results indicate that the vibration and surface displacement of the Mode 1 is in agreement with that of S0 Lamb wave, which validates that the new mode is S0 Lamb wave.Keywords：Surface Acoustic Wave(SAW) device;flexible substrate;polyimide substrate;piezoelectric film;wave mode;Lamb wave- 72
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Published：2020-08-13 -
Transmission error measurement of bevel gear pair under mounting distance adjustment
Abstract：The transmission error of a bevel gear pair can be obtained when its single flank engagement is measured at the best mounting position. This paper explores an algorithm for adjustment of the best mounting distance of the bevel gear pair and develops a measuring and control software of the transmission error. The measuring principle of the single flank engagement of bevel gear pair based on the best mounting position was introduced and the evaluation method for the transmission error was described based on the transmission error analysis, frequency spectrum analysis and precision grade evaluations. Statistical Process Control (SPC) is used to evaluate and monitor the computation process of tangential composite error and the tooth to tooth tangential composite error. Then the measurement and control software was developed based on the best mounting position to implement data acquisition and processing, graphic display, the optimizing search of best mounting position and SPC statistical analysis. The class diagram, sequence diagram, test case diagram and the main interface of the software were designed. Finally, the transmission errors of a gear pair before and after optimizing search of best mounting position were measured and the different transmission errors of a gear pair at different mounting positions were given. Experiment results show that the method and software mentioned in this paper is suitable for the measurement of bevel gear pairs or face gear pairs.Keywords：Bevel gear pair;Transmission error;single flank engagement;Mounting Distance;Statistical Process Control (SPC);Measurement and Control Software- 48
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Published：2020-08-13 -
Temperature characteristics of MEMS stress-testing structure and a stress-suppressing method
Abstract：The temperature characteristics of typical stress-testing microstructures were studied, and a stress-suppressing method was proposed. A stress-testing structure to represent the temperature characteristics of MEMS (Micro-electro-mechanical Systems) devices was designed and the influence mechanism of temperature on its nature frequency was analyzed. It points out that the axial thermal stress is the main factor affecting temperature stability of the nature frequency as compared with the material elastic modulus and the changes of structure size. Meanwhile, a stress-suppressing structure was designed to release the thermal stress and the machining residual stress. As the linear expansion coefficient of silicon was affected by temperature, the temperature characteristics of the axial stress and nature frequency for the stress-testing structure and stress-suppressing structure were studied by simulations and experiences. The results indicate that the axial thermal stress in stress-suppressing structure is suppressed to below two orders of that in stress-testing structure, and the frequency-temperature coefficient is reduced from about 5.0×10-3ppm/℃ to below 5.0×10-5ppm/℃ at -50 ℃ -+85 ℃. It concludes that the stress-suppressing structure suppresses the stress effectively, and suppresses the temperature influence factors into the MEMS system at the source. Moreover, the stress-suppressing structure can be used for other MEMS systems and can offer good temperature stability.Keywords：Micro-electronic-mechanicap System(MEMS);stress-testing structure;stress-suppressing stucture;temperature characteristic;thermal stress- 59
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Published：2020-08-13 -
Optimization design and test for bracket of star sensor in micro-satellite
Abstract：An optimization design method for the bracket of a star sensor was proposed to overcome a larger acceleration response value (Root Mean Square(RMS)) under random excitation of a micro-satellite. The basic theory of random response of the star sensor at an installation point was described, and the structure modal and acceleration response sensitivity of the satellite structure were analyzed. By taking the minimum random response RMS value at the installation point as the target, and the nature frequency and volume fraction for the restraint, an optimized model for the bracket of the star sensor was established and the topological optimization was performed for the model. Finally, the engineering analysis was carried out on the optimized model by using MSC.PATRAN& NASTRAN. The results show that the random response RMS value of the star sensor at the installation point has reduced more than 20%, the lightweight rate of the support structure has reached 50%. Furthermore, the bracket of star sensor was tested with a random vibration test platform. The results indicate that the relative error of the finite element analysis results and the experimental data is less than 15%, which shows that the designed performance parameters meet the design requirements and verifies the feasibility of the optimization method.Keywords：micro-satellite;star sensor;bracket;random response;finite element;topology optimization- 51
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Published：2020-08-13 -
Measurement of torque ripples for small torque motors
Abstract：According to the shortcomings in classical dynamic and static measurement for the torque ripple of a torque motor, a method to measure precisely the torque ripple was presented. The error sources of the classical torque ripple measurement methods were analyzed. Then a new method to measure the torque ripple based on the relative rotation of the stator to a rotor was proposed according to the unique characteristics of the torque motor with a separate structure and the ability to endure long time block. Under the condition of rotor block of the torque motor, the stator was rotated by the external force and the torque ripple of the motor was measured. Using this method, the errors of the inertia moment and the friction torque were effectively reduced. A set of measuring device was built based on the proposed method, and the relative rotation of the stator and rotor was realized with a worm gear mechanism. A verifying experiment was performed and the experimental results show that the measurement accuracy of the device with a range of 0-1 Nm is 0.3% and the linearity is 0.1%, which meets the requirements of torque motors for high precision toque ripple measurement.Keywords：torque motor;brushless direct current motor;torque ripple;torque measurement- 62
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Published：2020-08-13 -
Design of pneumatic wheel with progressive mesh abrasives
Abstract：A method to process pneumatic wheels with progressive mesh abrasives is proposed to overcome the shortcomings of traditional pneumatic wheels in abrasive grains fallen off easily and lower processing efficiency. On the basis of the idea of different abrasive layers layered progressive polishing, this method coats mesh abrasive layers with different thicknesses and mesh numbers on the surface of a pneumatic wheel. Then, it makes the tests of abrasive dropping amount and processing surface-quality to determine the grinding time and thicknesses of different abrasive layers. Finally, it processes pneumatic wheels with progressive mesh abrasives and researches their geometric precisions and the surface quality of processed workpieces. The experimental test shows that the optimum abrasive meshes of different layers should be 180#,120# and 80# with the thicknesses of 2 mm,0.21 mm and 0.3 mm respectively. Moreover, the thickness of each layer prepared meets the design requirement,and the error is within 5%. In processing,the outer abrasive layer wears off effectively layer by layer at the deal time. When the press amount is 2 mm and the rotating speed is 1 250 r/min, the pneumatic wheels implement the preliminary processing and the efficiency has improved more than 19%. These results demonstrate that the processing method improves significantly efficiency and automation by pneumatic wheels with progressive mesh abrasives.Keywords：pneumatic wheel;progressive mesh abrasives;laser hardening surface;layered progressive polishing;abrasive dropping amount;processing efficiency- 58
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Published：2020-08-13 -
Forward kinematics of 3-RRR flexure parallel mechanism used in lens micro-adjustment
Abstract：To meet the requirements of X/Y/θ adjustment in a lithography projection lens, a 3-RRR flexure parallel mechanism used in lens micro-adjustment was developed and its forward kinematics was researched. Firstly, the pseudo-rigid body model of the 3-RRR flexure parallel mechanism was established, the forward kinematic solution of the 3-RRR parallel mechanism was derived based on vector mathematical theory, and its theoretical Jacobian matrix was obtained. Then, the Finite Element Model(FEM) of the 3-RRR parallel mechanism was established in NX NASTRAN environment, and the FEM forward kinematic solution and the FEM Jacobian matrix were obtained. Finally, according to the experiment of the 3-RRR flexure parallel mechanism, the actual forward kinematic solution and the actual Jacobian matrix were acquired. The experiment results show that: the parameters of the actual Jacbian matrix are 0.5777, -0.304 0, -0.283 3, 0.002 1, 0.524 6, -0.516 5, 1.402 6, 1.481 9, 1.435 3,while the parameters of the theoretical Jacbian matrix are 0.612 9, -0.306 5, -0.306 5, 0, 0.530 8, -0.530 8, 1.444 6, 1.444 6, 1.444 6, respectively. The experiment results demonstrate that the forward kinematics can be exactly derived by the vector mathematical theory. The forward kinematic equation method for the 3-RRR flexure parallel mechanism is feasible when designing micro-motion mechanisms.Keywords：flexure parallel mechanism;lens micro adjusting mechanism;forward kinematic solution;pseudo rigid body model;vector algebra;Jacobian matrix- 70
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Published：2020-08-13 -
Detection of anodic bonding joint surface for SOI piezoresistive sensor
Abstract：As the packaging quality of a SOI(Silicon On Insulator) piezoresistive sensor is still dependent on manual detection, this paper proposes a method to implement its automatic visual inspection. The principle of piezoresistive sensor was analyzed, and the influence of the positioning accuracy of chips and the quality of bonding joint surface on sensor performance was investigated. By taking sensor performance and quality for a research target, a method to inspect the center deviation and bonding area was proposed for joint surface detection. Through analyzing the Hough circle detection and the actual image, the method implements the positioning accuracy detection. By analysis of the effect factors on sensor quality and statistics of the bubble area, the quality of bonding joint surface was measured. The proposed visual inspection method was verified in the practical packaging processing for sensor fabrication. Experimental results indicate that the method identifies the bubble with a diameter over 6 μm and the error of glass inner hole radius is about 0.015 mm. The method proposed satisfies the requirement of piezoresistive sensor package joint surface inspection by detecting center deviation and contributes to the automated inspection of packaging quality.Keywords：Silicon On Insulator (SOI);piezoresistive sensor;chip;packaging quality;visual detection;anodic bonding- 49
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Published：2020-08-13 -
Composite backward control for GMA and its application in high precision machining of variable ellipse pinhole
Abstract：For high precision machining of asymmetric boring holes, a control technology of the Giant Magnetostictive Actuator (GMA) used in a precision high-load pinhole boring device was explored. According to the hysteresis nonlinearity of the GMA, the mathematic mechanism of the quasi static modified Prandtl-Ishlinskii(P-I) model was analyzed briefly. To broaden the application frequency domain and to improve the precision of quasi static modified P-I model,a modified dynamic P-I model was proposed by combining with hysteresis phase feedforword compensation, and good control results were obtained. The experiment of back loop control system based on the dynamic modified P-I model and a PID controller was conducted. Results after compensation show that the hysteresis nonlinearity of GMA has reduced from 14.5 %-67.2 % to 1.5%- 4.3% at the case of open loop control, which controls the nonlinear error of the hysteresis . Moreover, a boring experiment for an oval pin hole was performed, the obtained ovality accords with the requirement of drawings, and verifies the feasibility of the proposed method. The research in this paper provides a new method for machining high-load oval pinholes.Keywords：oval pinhole;boring;Giant Magnetostictive Actuator (GMA);composite backward Control;modified P-I model;control of frequency and phase- 44
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Published：2020-08-13 -
Solution of correcting values on laser beam directing of fast steering mirror for mobile vehicle
Abstract：To improve the tracking and pointing accuracy of the laser shoot system for a mobile vehicle, a two-dimensional fast steering mirror was induced to the shooting system to correct the direction of laser beam. The relationship between the correction values of laser beam pointing of the fast steering mirror and the miss value of laser tracking as well absolute angles of the mirror in space was investigated. On the basis of the characteristics of laser shoot system and infrared tracking system , the ship-swaying coordinate transformation theory was applied to solution of the correcting values of the laser beam directing and the MATLAB was used to write the M-function and establish the SIMLINK model. The simulated result educes the related data between the laser direction correction value and the fast-reflector angle and a simple formula in the ±6' working range of the fast steering mirror. The experiment results indicate that arithmetic solution is correct,and the max static state error is 2.9", showing a higher precision. This arithmetic solution has been applied to control of the laser directing of the mobile armored car weapon equipment and its dynamic precision is the azimuth angle of 11.65",the pitch angle of 15.38",which satisfies the project needs.Keywords：tracking and pointing system;fast steering mirror;laser directing;correcting value;ship-swaying coordinate conversion- 50
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- 14
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Published：2020-08-13 -
Life test of solid-lubricated bearing assembly for scan mechanism of space camera
Abstract：An accelerated vacuum life test for solid-lubricated bearing assemblies of the scan mechanism in a space camera was performed to obtain their working life. The working life of MoS2 solid based solid lubrication bearing assembly under a small angle oscillation was researched. The continuous oscillation of 4 pairs of bearings at ±6°was simulated and tested. During the life test, the friction moment, the current of motor and the temperature rise of bearings were inspected to estimate their running states. The experiments show that the life test has run very well, the working life of the bearing assemblies is 6.2×107 times. The dimensional precision and running accuracy of the bearings were measured after life test, and then the dissection analysis of the bearing assemblies was also taken. The results indicate that the dimensional precision and running accuracy of the bearings are the same as that of the life test and the lubrication condition of the bearings is good. These results validate that the working life of solid-lubricated bearing assemblies satisfies the requirement of task in orbit. It provides technological supports for the long life design of solid-lubricated bearing assemblies for scan mechanisms of space cameras under smaller angle oscillation.Keywords：space camera;scan mechanism;solid-lubricated bearing;MoS2;oscillation;accelerated life test- 41
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Published：2020-08-13 -
Tool wear in laser ultrasonically assisted cutting cemented carbide and its effect on surface quality
Abstract：A laser ultrasonically assisted machining was proposed based on laser heating assisted machining and ultrasonically elliptical vibration machining. A series of comparison experiments were conducted by conventional cutting, ultrasonically elliptical vibration cutting, laser assisted cutting and laser ultrasonically assisted cutting for YG10 cemented carbide with Polycrystalline Cubic Boron Nitride(PCBN) tools. The tool wear mechanism and its effect on surface quality of a workpiece were discussed by detecting the tool wear conditions,the surface morphology and surface roughness of the workpiece and by analyzing the energy spectrum of worn areas with a Scanning Electron Microscopy (SEM). The comparison was carried out with conventional cutting, ultrasonically elliptical vibration cutting and laser assisted cutting. The results show that the flank wear of PCBN tool obtained by laser ultrasonically assisted cutting is reduced, and the average surface roughnesses of the workpieces are reduced by almost 79%,60% and 64% respectively. Therefore, the tool life is obviously lengthened and the workpiece surface is smoother by laser ultrasonically assisted cutting. In laser ultrasonically assisted machining cemented carbide, the wear on rake face is characterized by the smooth and uniform crater, the flank face has a narrow triangular wear land, shallow pits and scratches, and PCBN tool failure mechanisms are the synergistic interaction of adhesive wear, oxidation wear and abrasive wear.Keywords：laser ultrasonically assisted cutting;cemented carbide;polycrystalline Cubic Boron Nitride(PCBN) tool;tool wear;surface quality- 64
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Published：2020-08-13 -
Analysis and experiment of gravity deformation for large aperture rectangular mirror set
Abstract：The surface figure deformation of a large aperture rectangular mirror set in a space optical remote sensor under the gravity was explored and the accuracy of simulation analysis results by Zernike polynomial fitting and spherical equation fitting methods were verified and analyzed quantitatively. The basic principles of Zernike polynomial fitting and spherical equation fitting were introduced, and the gravity deformation of the large aperture rectangular mirror set under the gravity was simulated and analyzed by the two fitting methods mentioned above. On the basis of error composition principle, a calculation method of the mirror surface figure change was proposed according to the two test results in the grounded turn-over experiment. For the compensation phenomenon between the off-axis magnitude and the surface astigmatism of an off-axis mirror in the process of the mirror surface test, a method was proposed to determine the relationship between the amount of off-axis magnitude and the surface astigmatism. Experimental results show that the fitting accuracy of Zernike polynomial method is 74.2%, and that of spherical equation fitting method is 12.6%, which is in good agreement with the error evaluation of simulation results 10%. It suggests that the polynomial fitting method is not suitable for the rectangle mirror due to its limitation, however the accuracy of the spherical equation fitting method can meet the engineering requirements.Keywords：space optical remote sensor;large aperture mirror;Rectangular mirror;gravity deformation;simulation analysis;Zernike polynomial fitting;spherical equation fitting- 67
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Published：2020-08-13
Micro/Nano Technology and Fine Mechanics
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MTF space-variant blurring resulted from platform vibration of TDICCD camera
Abstract：The satellite vibration could not only result in the irregularity of pixel sampling of TDI(Time Delay and Integration)CCD camera and the inconsistency of spatial distribution of pixel disc of confusion, but also could make the Modulation Transfer Function (MTF)of image generate space variation caused hereby. Consequently, the restoration quality by vibration of high-definition image may be limited. Starting with the action mechanism of satellite vibration on sampling process of push-scanning image by TDICCD camera and combined with theoretical derivation and simulation research, this paper obtained the blurring and characterization methods of space variance of image resulted from platform vibration. Then, based on restoration model of vibration, the influences of MTF space-variant blurring on restoration processing errors were deduced and obtained. In addition, according to the actual satellite image, the restoration experiment was carried out. The experimental results indicate that: when the MTF space-vibrant blurring of image is lower than 15%, because of vibration, the structural similarity between image which has been treated by restoration and ideal image may be superior to 0.95, and the image distortion caused by processing error may not impact interpretation quality.Keywords：satellite vibrations;TDICCD camera;image restoration quality;space-variant MTF- 57
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Published：2020-08-13 -
Model segmentation and packaging in 3D printing
Abstract：To improve the printing efficiency of three-dimensional model of 3D printing technology and reduce the cost of printing materials and shorten printing time, a kind of global optimal model segmentation and packaging algorithm was proposed. Firstly, the model given was segmented into several blocks with the shape of pyramid. Then, the advantages of a kind of improved taboo search algorithm was taken to search for the optimal packaging scheme, and the volume of backing materials were reduced as far as possible. According to the volume of blocks, the initial solution which is beneficial to global optimization was provided, and by controlling neighborhood generative rule and candidate solution, the search was more efficient and the speed of optimization searching was sharply improved. Finally, various components formed by printing were compounded into the entirety. The experimental results indicate that for generated packaging scheme, the printing time with 14%-38% is saved, while the printing materials with 21%-46% are also saved. From the model segmentation by this method, there is few number of blocks caused, efficient and reasonable packages, which not only availably improves printing efficiency but also reduces printing time and backing materials consump- tion.Keywords：3D printing;model segmentation;packaging algorithm;taboo search- 87
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Published：2020-08-13 -
Threat assessment of support vector machine optimized by Krill Herd algorithm
Abstract：To put forward the method of threat assessment of support vector machine optimized by Krill Herd algorithm based on the traditional support vector machine optimization method, so as to improve the forecast precision of target threat assessment. The thesis introduces the principles of Krill Herd algorithm and support vector machine and optimize the penalty parameter and kernel function parameter in the support vector machine with Krill Herd algorithm to find the optimal penalty parameter and kernel function parameter; establishes the model of target threat assessment of the support vector machine optimized by Krill Herd algorithm and achieves the target threat assessment algorithm based on this model. Collect 90 sets of original data to form the training set and 30 sets of data to form the test set to carry out simulation experiment on the target threat assessment algorithm. The experimental result shows that the forecast error of the support vector machine optimized by Krill Herd algorithm is 0.002 91 which is less than that of the support vector machine optimized by particle swarm algorithm or firefly algorithm. It can conclusion that the target threat assessment method of the support vector machine optimized by Krill Herd algorithm can effectively complete the target threat assessment.Keywords：threat assessment;Krill Herd;support vector machine;parameter optimization- 49
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Published：2020-08-13 -
Research on noise analysis and signal processing method of light addressable potentiometric sensor
Abstract：Considering that the response signal of light addressable potentiometric sensor (LAPS) is quite week and the traditional method for extraction of fundamental component of frequency domain is easily impacted by signal drift and stochastic noise, a kind of two-step signal processing method based on the mean square root of component of frequency domain and Kalman filtering was proposed. Based on the theoretical model of devices of light addressable potentiometric sensor, the equivalent circuit model was established; the expression of output signal was deduced, and the causes of drifting and noise as well as inhibition methods were analyzed. Through tests, the solutes with different pH values were detected, and the photocurrent signal outputted by systems was collected. The mean square roots of breadth value of spectral line of fundamental component, second harmonic component and third harmonic component in the frequency domain after Fourier transformation were calculated. Then, the Kalman filtering was implemented for characteristic curve of normalized current-bias (I-V). The experimental results indicate that the two-step signal processing method based on the mean square root of component of frequency domain and Kalman filtering makes the mean square error (MSE) of testing result reduced by 97%, and the influences of signal drift and stochastic noise on testing result are obviously decreased compared to the simple method to extraction of fundamental component.Keywords：Light Addressable Potentiometric Sensor;signal drift;stochastic noise;Mean Square Root of Component of Frequency Domain;kalman filtering- 45
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Published：2020-08-13 -
Denoising of three-dimensional point data based on classification of feature information
Abstract：To ensure no loss of feature information of model and effectively eliminate the noise at the time of acquisition of three-dimensional point cloud data, a kind of denoising algorithm based on classification of three-dimensional point cloud feature information was proposed. Firstly, the principal component analysis and conicoid fitting method were adopted to estimate the differential geometry information of three-dimensional point cloud. Then, according to the local feature weight of average curvature of point cloud, the cloud data was divided into flat region with little feature information and region with rich feature information. Pursuant to different feature regions, the average filtering algorithm with neighborhood distance and self-adaptive bilateral filtering algorithm were respectively adopted to perform denoising and filtering. The experimental results indicate that the maximum error of point cloud data is 0.144 7mm, and standard deviation is 0.021 0 mm after filtering. Under different noise intensities, this denoising algorithm may reach preferable denoising effects and reserve the high-frequency feature information of point cloud.Keywords：Point cloud denoising;Feature classification;bilateral filtering;Differential geometry information- 79
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Published：2020-08-13 -
Vibration parameter detection of space camera by taking advantage of CMOS self-correlation Imaging of plane array of roller shutter
Abstract：To obtain the amplitude-frequency feature of vibration of space camera during the camera shooting of rail, a kind of vibration parameter detection method of space camera based on CMOS self-correlation imaging of plane array of roller shutter was proposed. Based on CMOS imaging principle of roller shutter, for the continuous shooting of same photographic field, a group of image sequences with correlation were obtained. The images formed were compared through gray projection algorithm to calculate relative shift. The shift data was fitted, so that the vibration parameters of space camera were calculated according to fitting results. The confirmatory experiment shows that the relative error of cycle detection of two-dimensional vibration is no more than 2%, and the absolute error of amplitude detection is no more than 1 pixel. The experimental results indicate that this method may detect high-frequency vibration by taking advantage of low frame-frequency image sequence, so the data transmission and processing pressure of detection algorithm are produced by a large margin; It provides the possibility to realization of star embedded type of detection algorithm, and has good application to push-broom camera and staring camera.Keywords：CMOS of roller shutter;self-correlation imaging;vibration parameter;gray projection;fitting- 66
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Published：2020-08-13 -
FEKO sparse micro-doppler modeling and CS reconstruction method
Abstract：The method of understanding and resolving the micro-Doppler was proposed. As the radar cannot achieve the randomness of the transmission pulse, and the electromagnetic simulation software FEKO was adopted to achieve the radar echo simulation with random emission time, and it was used for algorithm verification. In the progress of simulation, by considering about the complexity of the jogging target movement, the combination of FEKO and the MATLAB was adopted to realize the dynamic updating of the target's posture. Firstly, the motion state of each sparse moment target was to be calculated by MATLAB, then the parameters would be transmitted to the FEKO so as to obtain the electromagnetic scattering date under the corresponding attitude angle of different moments, at last, the micro-Doppler frequency without blurry would be worked out with the algorithms hereof. The simulation was executed to five different jogging models, and the simulation results have no difference with the theoretical results, therefore, the feasibility of the algorithm and the efficiency of the simulation model can be verified.Keywords：Micro-doppler;Radar;Compressed sensing;FEKO;electromagnetic scattering- 44
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Published：2020-08-13 -
A super-frame processing method for infrared image based on accumulation of different integration time frame
Abstract：Since the dynamic response range of the detector component within the period of single framing for most regular infrared imaging system is limited, and the super-frame calculation can not be conducted without the help of other complicated devices or dedicated circuits, a method based on accumulation of different integration time frame for infrared image super-framing was put forward. In this method, a research was conducted on the whole super-framing process by means of electronic method, the reason for limited dynamic response range of the infrared detector was analyzed, and the principle, advantages and disadvantages of the frame integration method was introduced. Then non-uniform correction, frame information integration and new frame mapping were conducted on images obtained under different integration time. It is showed in the test that the method helps to improve the NETD of the system, capture more original image information, enrich the gray level of the image, and increase the image information entropy. By using this method, the dynamic response range of the detector can be expanded, more original scene information can be captured, and the detection sensitivity and signal to noise ratio of the image output signal can be improved.Keywords：infrared image;super-frame processing method;integration time;Dynamic range;signal to noise ratio- 62
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Published：2020-08-13 -
On diagram-based three-dimensional reconstruction of UAV image
Abstract：In response to low operation efficiency of the incremental algorithm for structure recovery from motion in three-dimensional reconstruction of UAV (Unmanned Aerial Vehicle) image, a diagram-based method for reconstruction of UAV image was proposed. In this method, data obtained from low-precision position and orientation system of UAV was adopted to roughly estimate the overlapping relationship between images, SIFT matching was conducted between related images, random sample consensus algorithm and three views constraint were used to weed out the connected relation between weakly-related images, depth-first search was applied to obtain the connected component of the images finally involved in reconstruction, and then a steady diagram for strongly-related images was designed. Then based on the relative position and attitude parameter of the images, the least square method was adopted to work out the consistency rotation parameter, the three views constraint and linear programming were used to solve the consistency location parameter, and then a bundle method-based adjustment optimization was conducted. It indicates that the operating speed of this method is at least 2.6 times faster than that of the typical incremental Bundler algorithm, the three-dimensional points increased by 76.5%, and it can more closely recover the original geometry form. This method, while perfecting the reconstruction effect, improves the treatment efficiency and can meet the requirement for quick response of UAV.Keywords：UAV;three-dimensional reconstruction;diagram;three views;linear programming- 32
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Published：2020-08-13 -
On calibration of camera response function free from the impact of dynamic problem
Abstract：Calibration of camera response function was carried out by means of brightness mapping between images rather than pixel information of the images themselves, which could help avoid the impact of image registration errors caused by image system shaking or dynamic problem in the shooting site on the follow-up calibration algorithm. The method of histogram regularization was adopted to analyze the statistical characteristics of different color channels with different light levels between images of different exposures, and the brightness mapping function between different image pairs were obtained. Then, the over-determined equation model was worked out by combining the brightness mapping function between different image pairs with the histogram of each frame image. For the last step, the camera response function was obtained by means of the least square method. It shows that the calibration algorithm for camera response function can help overcome the impact of dynamic problem, and the grouping experiment on images with different input frames indicates that the fewest images with 4 input frames can achieve the optimal camera response function calibration value.Keywords：brightness mapping function;camera response function;histogram modeling;dynamic scene- 57
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Published：2020-08-13 -
SART + TVM reconstruction algorithm based on improved Ray-Box Intersection weight coefficient matrix
Abstract：Based on the problem of uniform sampling and sparse reconstruction, a research on calculation method for two weight coefficient matrix, including Ray-box Intersection and traditional bilinear interpolation, was conducted. Improvement on logic flaws of Ray-Box Intersection was made, and the improved algorithm was put forward by combining line generating method with the slope of the ray and pixel location. In this algorithm, the starting point and terminal point of the ray across the reconstruction region can be obtained through algebraic relation, and then the maximum integer no greater than its coordination is used to, in accordance with the ray slope along the X direction and Y direction, work out the lower left coordination collection of all pixel blocks passed through by the ray in the projection area using the line generating method. For each pixel block, the distance of intersection point between the ray and pixel block is their weighted value. It indicates that compared with the weight coefficient matrix algorithm of Ray-Box Intersection, speed of the improved one has increased by 96%, and the peak signal to noise ratio has increased by 19%. In comparison with the bilinear interpolation algorithm, rate of convergence of the improved one is faster, and the peak signal to noise ratio has increased by 5% under the same time period. The improved Ray-Box Intersection algorithm can achieve better reconstructed images and clearer details.Keywords：simultaneous algebraic reconstruction;minimization of total variation;Ray-Box Intersection algorithm;bilinear interpolation algorithm;weight coefficient matrix- 52
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Published：2020-08-13 -
Inversion of IRAS/FY-3B atmospheric temperature and humidity profiles based on fast locally linear regression
Abstract：The FLLR algorithm was developed to retrieve atmospheric temperature and humidity profiles from IRAS/FY-3B data.The observation samples required by the algorithm are IRAS /FY-3B L1 observation value and time-spacing matching data of AIRX2RET V5. Take the year of 2011 for an example, the observation sample was obtained in the survey region of 180°W~180°E and 60°N~60°S under the condition that absolute difference of the observation time is less than 15min and absolute difference of the observation angle is lower than 2°, and then an evaluation on the sample was conducted. Based on the observation sample matching, a comparison and analysis was carried out on FLLR algorithm and LLR algorithm, D Matrix algorithm and non-linear neural network algorithm. Then the year-round atmospheric temperature and humidity profiles in 2011 were obtained from IRAS/FY-3B L1 data inversion by using the FLLR algorithm, and the profile in the first quarter of 2012 can be achieved through extrapolation inversion. The last step was a precision test on the inversion results of 2011 by means of corresponding ECMWF reanalysis data and RAOB radiosonde observation, as well as verification on the extrapolation inversion results in the first quarter of 2012. It demonstrates that compared with D Matrix algorithm, the root mean square error in the inversion of the atmospheric temperature and humidity profile by using the FLLR algorithm has respectively reduced by ~0.8K and ~0.5g/kg, while its precision is quite the same as the non-lineared neural network algorithm. With respect to ECMWF reanalysis data, the root mean square error of the atmospheric temperature and humidity profile inversion is respectively lower than 2.5 K and 2.3 g/kg, and for RAOB data, the root mean square error is lower than 3.5 K and 2.0 g/kg respectively. The root mean square error of the extrapolation inversion in the first quarter of 2012 is respectively lower than 2.5 K and 1.6 g/kg, and the precision is almost the same in different algorithms. The inversion precision of IRAS/FY-3B atmospheric temperature and humidity profile is quite the same as the precision of MOD07 V5 atmospheric profile.Keywords：FY-3B;IRAS;fast locally linear regression algorithm;atmospheric temperature and humidity profile inversion;accuracy validation- 75
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Published：2020-08-13
Information Sciences
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