bob手机在线登陆学报自然版

2019, 39(11): .

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Abstract:

2019, 39(11): .

Abstract(513) PDF(272)

Abstract:

Modeling and Parameter Matching for the Pilot Stage of Jet Pipe Servo Valve

HU Jian-jun, YANG Ze-he, JIN Yao-lan, HUANG Zeng, ZHU Qing, KONG Xiang-dong

2019, 39(11): 1101-1106. doi:10.15918/j.tbit1001-0645.2018.430

Abstract(993) PDF(653)

Abstract:
In order to study the influence of the structural parameters of the jet pipe servo valve on the performance of the pilot stage, a pilot stage numerical model of the servo valve was established, and the numerical simulation results of the pilot stage flow field was verified by using the PIV technology. The effects of nozzle hole diameter, receiving hole diameter and distance between nozzle and receiver on the restoring pressure difference and its stability were analyzed by means of numerical method. The optimum matching range of structural parameters of the pilot stage under three different flow rates of servo valves was obtained. The results show that, when the diameter of the nozzle is 0.22~0.28 mm, the optimum range of the diameter ratio of the receiving hole to the nozzle hole diameter is 1.1~1.2, and the optimum range of the ratio of the distance between nozzle and receiver to the nozzle hole diameter is 0.6~0.8. The pilot stage structure parameters have a direct influence on the stability of the differential pressure of the receiving hole. The unstable of jet boundary layer by receiver wedge due to parameter mismatch is an important reason for differential pressure oscillation in receiving hole.

Effect of Profile Parameters on Tooth Thickness for Variable Cross-Section Scroll Compressor

HOU Cai-sheng, LIU Tao

2019, 39(11): 1107-1112. doi:10.15918/j.tbit1001-0645.2018.273

Abstract(898) PDF(488)

Abstract:
In order to investigate changing laws of tooth thickness of variable thickness scroll compressor quantificationally, a profile combined with the involute of circle, high curve and arc was proposed, and a mathematical model was established based on the geometric model to calculate the tooth thickness of a variable cross-section scroll tooth. The influence factors of tooth thickness were analyzed in detail by solving the mathematical model, and the relation between tooth thickness and profile parameters were established precisely. The research shows that the presented mathematical model can accurately describe changing laws of tooth thickness of variable cross-section scroll tooth, the size of tooth thickness as well as the initial position of variable tooth thickness can be quantitatively designed according to the design requirements, which provides the way of thinking for flexible design of scroll tooth. The mathematical model can also be applied to calculate the tooth thickness in other combination profiles.

Experimental Study on Pressure Fluctuation Characteristics and Fuel Property Parameters of 250 MPa Common Rail System

ZHANG Zhi-hao, YANG Qing, SUN Bai-gang, WU Dong-wei, XU Dan

2019, 39(11): 1113-1117. doi:10.15918/j.tbit1001-0645.2018.314

Abstract(764) PDF(343)

Abstract:
250 MPa ultra-high pressure common rail fuel system was tested, the pressure fluctuation characteristics under different pressure and temperature conditions were obtained. Then, the pressure wave velocity and the total volume elastic modulus of the fuel and high pressure pipe were obtained according as the pressure fluctuation between the injector end and the common rail end. Finally, the calculation formula of the pressure wave velocity and the total volume elastic modulus were obtained for the injection pressure in the range of 180 to 250 MPa and the temperature in the range of 15 to 40℃.

Dynamic Performance of Radial Flow Magneto-Rheological Valve and Damping Performances of Valve-Controlled Cylinder System

HU Guo-liang, ZHANG Jia-wei, YU Li-fan, ZHONG Fang

2019, 39(11): 1118-1125. doi:10.15918/j.tbit1001-0645.2018.182

Abstract(894) PDF(428)

Abstract:
In order to improve the pressure drop ability of the magneto-rheological (MR) valve, a radial flow MR valve with higher pressure drop ability was proposed. Firstly, the working principle was analyzed in detail and a mathematical model of radial flow MR valve was established. And then, a dynamic test system was constructed to test the pressure drop and response time of the radial flow MR valve under different applied direct currents and flow rates. The experimental results show that the pressure drop is 3.2 MPa at the applied direct current of 1.2 A, and the response time is between 100 ms and 150 ms. Finally, the damping performances of the radial flow MR valve-controlled cylinder system were analyzed. The damping performance tests were carried out under different applied direct currents, frequencies, and amplitudes. The experimental results show that, the system can output a larger damping force, and the maximum damping force can reach 5 kN. Furthermore, the damping force can be continuously adjusted under the different applied direct current, and the adjustable range is wider too. The effects of piston velocity on the damping force are little, and the system can generate stable damping forces in a variety of operating conditions.

Study of Autonomous Vehicle Following Method in Unstructed Environment

ZHANG Hai-ming, GONG Jian-wei, CHEN Jian-song, WANG Yu-chun

2019, 39(11): 1126-1132. doi:10.15918/j.tbit1001-0645.2018.309

Abstract(1161) PDF(403)

Abstract:
A kind of multi-sensors fusion method was proposed for autonomous vehicle following application in unstructed environment to solve the problem of the guide vehicle locating in autonomous vehicle following task, and to obtain relative position and speed of guide vehicle in real time. Firstly, oriented by the task requirements, the sensors selection work was completed in term of unstructed environment features by on board experiments results. Then, a joint calibration work-flow was designed for the selected millimeter wave radar (MMW) and camera to realize data spatial fusion. And several works were carried out, including designing the targets distance related transversal distance constraint threshold, analyzing the target data reliability based on annals frame to solve radar data jump and virtual detection phenomenon in unstructed environment and to accomplish radar valid targets extraction, creating the candidate vehicle detection boxes with changeable area based on camera pin-hole imaging principle. Finally, an output information procedure was designed with regard to vehicle following application, based on the mainstream deep learning framework about object detection. On board test results indicate that, the proposed method can satisfy the basic requirements of vehicle following application in most off-road scenes with a certain output stability and accuracy.

Adaptive Road Extraction Method in Different Scene Based on Deep Learning

DING Ze-liang, HU Yu-hui, GONG Jian-wei, XIONG Guang-ming, LÜ Chao

2019, 39(11): 1133-1137. doi:10.15918/j.tbit1001-0645.2018.312

Abstract(1192) PDF(524)

Abstract:
In order to meet the adaptability of autonomous vehicles to the cross-country environment and to improve the understanding ability of autonomous vehicles to the environment, higher requirements for environmental awareness system must be put forward.The most critical point in environmental awareness system is lane extraction or road extraction.However, the cross-country environment is more complicated in comparison with the structured road in the urban environment.The main reason lies in high complexity of the cross-country environment, and the extraction algorithms are different for different scene.A variety of cross-country scenes were studied, and a road segmentation method that adaptable to different scene was proposed.Firstly, a large number of data were collected for the cross-country environment, and the corresponding datasets were established.Secondly, these scenes were arranged to be identified by using deep learning method.And then a semantic segmentation algorithm was applied to segment the roads under different scenes.Finally, the whole algorithm modules were unified to obtain test results.

Research on Hysteresis Characteristics of the Thrust of Voice Coil Motor

LIU Hui, HE Rong, WU Wei, ZHANG Qi-lin, LIU Yang

2019, 39(11): 1138-1143. doi:10.15918/j.tbit1001-0645.2018.277

Abstract(872) PDF(321)

Abstract:
The thrust control accuracy was reduced by the hysteresis characteristic of the voice coil motor (VCM) and the pressure accuracy of a valve controlled by VCM is restricted. In order to achieve the precise thrust control of VCM, a thrust hysteresis model based on Preisach model was proposed. The feasibility of the model was verified by experiment. An inverse hysteresis model of VCM was established and an open-loop inverse compensator was designed. The thrust experiments of VCM with inverse compensator and without inverse compensator were carried out. The results indicate that the hysteresis loop of VCM with inverse compensator is significantly smaller than VCM without the compensator. The maximum absolute error of VCM with inverse compensator is 0.2 N, and relative error is basically maintained within 3%. That of VCM without inverse compensator reaches 0.75 N, and relative error varies greatly. The magnitude of change in the thrust absolute error after compensation is reduced by 73%. The hysteresis characteristic of the thrust of VCM is effectively compensated by the inverse compensator, and the thrust control accuracy is improved.

Optimal Control of Wheel Slip Ratio of Distributed Electric Drive Unmanned Platform

YE Yu-bo, WEI Chao, LIU Yu-ang, XU Zhen-yu

2019, 39(11): 1144-1148. doi:10.15918/j.tbit1001-0645.2018.267

Abstract(944) PDF(244)

Abstract:
The wheel longitudinal slip ratio can affect the dynamic ability and stability of the unmanned platform directly. So, the slip ratio control problem was firstly analyzed in this paper, and then a dynamic model of the longitudinal slip ratio of the wheel was established based on tradition analysis model, considering the torsion coupling of wheels and the observation error of vehicle speed. Based on this, the optimal system design and controller solution were carried out, considering the uncertainty and external disturbances. Finally, the controllers designed for the pavements were simulated and verified with simulation software CarSim. Results show that, the robust optimal controller can ensure that the wheel longitudinal slip rate keeps stably at about 0.2 under different working conditions, achieving the control effect basically. Compared with the case without control, the wheel slip rate can be obviously controlled, ensuring the wheel speed consistent and avoiding the wheel stall. At the same time, the acceleration of the vehicle can be improved and the dynamic performance can be enhanced.

Evaluation Method for Driving Capability in the Longitudinal and Lateral Scenarios

SUN Bo-hua, DENG Wei-wen, WU Jian, LI Ya-xin

2019, 39(11): 1149-1154. doi:10.15918/j.tbit1001-0645.2018.341

Abstract(786) PDF(382)

Abstract:
To allocate driving privilege in a reasonable way for shared control of intelligent vehicle, an evaluation method was proposed for driving capability in the longitudinal and lateral scenarios, to improve the safety and comfort of intelligent vehicles. Firstly, the driving capability was defined and analyzed and car-following stimulate for longitudinal scenario and moving double lane change stimulate for lateral scenario were designed. Data collection was conducted based on a driver-in-the-loop intelligent simulation platform (DILISP). And then, a driving capability identification model was established based on Hammerstein identification process and a principal component analysis (PCA) was used to decouple and reduce the dimension of the key parameters in Hammerstein model. Finally, a driving capability classification method was carried out based on a combination method of ant clustering algorithm (ACA) and subjective questionnaire. The evaluation equation for driving capability was developed by multiple linear regression(MLR). Results show that the proposed evaluation method for driving capability in the longitudinal and lateral scenarios can achieve accurate and reliable evaluation results. The mean identification accuracy of longitudinal and lateral driving capability identification model and fitting accuracy of evaluation equations can reach 90%.

Source Code Defect Detection Based on Deep Learning

WANG Xiao-meng, ZHANG Tao, XIN Wei, HOU Chang-yu

2019, 39(11): 1155-1159. doi:10.15918/j.tbit1001-0645.2018.396

Abstract(1075) PDF(368)

Abstract:
The development and progress of traditional source code defect analysis techniques rely mainly on analysts' understanding of safety issues and long-term experience. To improve the quality of source code defect detection and report, a source code defect detection method was proposed based on deep learning algorithm. Firstly, introducing an abstract syntactic tree of program source code and the data stream features, and training source code defect sorter, the method was arranged to achieve source code defect detection according to the deep learning algorithm. And then,analyzing the abstract syntactic tree of source code and the semantic and syntactic feature contained in the data stream, a general framework was proposed for deep learning based source code defect detection according to the key theories, deep learning algorithm and word nesting algorithm in nature language processing. Finally, an open data set SARD was used to validate the proposed method. The experimental results show that, the proposed method can learn semantic and syntactic features hidden in the source code and outperform the existing methods in terms of accuracy, recall rate, false positive rate, and false negative rate.

Structured Data Management Method Based on Scalable Blockchain Storage

YU Bin, LI Xiao-feng, ZHAO He

2019, 39(11): 1160-1166. doi:10.15918/j.tbit1001-0645.2018.079

Abstract(963) PDF(436)

Abstract:
To solve the problems about the scalability of blockchain storage capacity, storage structure, etc, a structured data management method based on scalable blockchain storage was presented. Based on node dynamic net and the DHT protocol, only part of the data was needed to be stored in every peer to realize the data management. The data signature and timing verification were used to ensure the security of data management, and structured data was stored in the local database to extend the business data management. Test results show that, this method can achieve structured data management based on scalable blockchain storage, make the best of the network resources, reduce the storage pressure of each peer, improve the efficiency of data storage, and promote the development of block chain application in the foreseeable future.

Electromagnetic Radiation Effect Prediction of Random Noise for Communication Equipment

LI Wei, WEI Guang-hui, SUN Shu-qing, PAN Xiao-dong, WAN Hao-jiang

2019, 39(11): 1167-1172. doi:10.15918/j.tbit1001-0645.2017.311

Abstract(812) PDF(385)

Abstract:
To fully analyze the random noise radiation interference on the frequency equipment, the electromagnetic effect of communication equipment under Gaussian random noise radiation was studied. Analyzing the in-band interference mechanism of power-sensitive communication equipment, a prediction model was established and the effect index was defined. The random noise radiation interference of the communication equipment was predicted by calculating the effect index. Taking the VHF radio as the experimental object, sine and AM wave, Gauss white noise, narrowband noise tests were carried out respectively. The interference probabilities under different test conditions were set as 100%, 98.7%, 99.9%, 99.1%. The test results show that the proposed model and prediction method can effectively forecast the viability of the communication equipment under the random noise radiation interference, possessing important engineering application value.

The Effect of EUT on Environment Electromagnetic Radiation E-Field Test

WEI Guang-hui, JI Kai-fu, MENG Ling-yuan

2019, 39(11): 1173-1179,1186. doi:10.15918/j.tbit1001-0645.2017.312

Abstract(668) PDF(309)

Abstract:
To reduce the effect of EUT on the measurement of environment E-field intensity and to improve the measurement accuracy of electromagnetic radiation susceptibility test, a method was proposed by combining electromagnetic field numerical calculation with experimental verification. A cube electrical conductor was taken as EUT model to study the change laws of E-field distribution effected by EUT in uniform electrical field environment or electromagnetic reverberation chamber. Taking the environment E-field intensity before the EUT placed as reference, the relative error caused by electric field distortion in typical direction was determined, and the curve of the measurement error varying with the distance to the EUT was presented. It is concluded that the relative measurement error of environment E-field intensity is less on the diagonal line of EUT front surface,the error can be decreased to ±10% or less when the distance is greater than the wavelengthλ. As for the low frequency measurement, while the distance is in the interval of(0.15~0.25)λ, the measurement error can be decreased to 15%, which can meet the test error requirements. When the EUT is put into the reverberation chamber, the E-field distortion mainly affects the mean E-field intensity distribution near its surface, as long as the distance to the surface of EUT is greater than 0.4λ, the measurement error caused by E-field distortion can be decreased to 2 dB, when the distance to the surface of EUT is in the interval of(0.5~0.9)λ, the relative error of E-field is smaller, it is best to measure the environment E-field intensity in this interval.

Extraction and Verification on Equivalent Thermal Conductivity of PI-TSV

DING Ying-tao, ZHOU Ming-rui, CHENG Zhi-qiang, XIAO Lei

2019, 39(11): 1180-1186. doi:10.15918/j.tbit1001-0645.2017.351

Abstract(930) PDF(396)

Abstract:
Compared with the traditional T/R modules, the 2.5D integrated silicon-based T/R modules implemented with TSV interposer are smaller, more integrated and possess better heat dissipation. Through-silicon-via (TSV) is one of the key structures. It is difficult to realize the finite element thermal simulation of complicated 2.5D integrated T/R modules, thus a solution which utilizes the equivalent thermal conductivity of TSV was employed to simplify the finite element analysis (finite element analysis, FEA) in this paper. The FEA of TSV with polymide liner (PI-TSV) was carried out and the structural parameters were changed to detect their effects on PI-TSV equivalent thermal conductivity. Finally, the empirical equation of PI-TSV equivalent thermal conductivity with respect to copper pillar diameter, insulation thickness and TSV pitch was presented.

Design and Optimization of Multi-Modulus-Divider forK-Band Fractional-N Frequency Synthesizer

WANG Zheng-chen, WU Zhao-bo, QI Quan-wen, WANG Xing-hua

2019, 39(11): 1187-1191. doi:10.15918/j.tbit1001-0645.2017.329

Abstract(1022) PDF(339)

Abstract:
A multi-modulus-divider (MMD) was designed based on TSMC 90 nm CMOS process, achieving a division range of the MMD from 32 to 39. The block diagram of MMD, including double-modulus-divider,Scounter andPcounter were discussed in detail. Time sequence requirement of thePcounters with and without retime circuit were analyzed and discussed. The proposed MMD was integrated into aK-band fractional-N frequency synthesizer. The measurement results show that in-band phase noise performance can be optimized about 15 dB through the modified MMD. The measurement results exhibit the phase noise performance can achieve -81.3 dBc/Hz and -72.44 dBc/Hz at 10 kHz frequency offset and 1 kHz frequency offset, respectively.

Research on High Speed and Hardware Efficient Parallel Blind Equalization and Its FPGA Implementation

WANG Ai-hua, CHE Wen, FANG Jin-hui, MENG En-tong

2019, 39(11): 1192-1197. doi:10.15918/j.tbit1001-0645.2017.353

Abstract(822) PDF(372)

Abstract:
Aiming at the inter-symbol interference (ISI) caused by the multi-path interference, the inconsistency of the in-band amplitude phase of the RF device and the ADC, and the deviation of the timing sampling time in the high-speed demodulation system, a hardware efficient parallel blind equalization was proposed based on constant model arithmetic (CMA). The structure was designed with the relaxed look-ahead technique and the fast FIR algorithm. In the case where the symbol rate is much higher than the FPGA clock frequency, the blind equalization maximizes the data throughput requirements with less hardware cost by using a low complexity pipelined parallel structure. The architecture is implemented on the Xilinx XC7VX690T hardware platform and applied to the high-speed demodulation system with 600 Ms/s symbol rate, which greatly improves the quality of the signal, thus verifying the feasibility and efficiency of the algorithm.

Compressive Sensing Based Chanel Estimation for mMTC System

SONG Wei, KE Ma-long, LIAO An-wen, QIAO Li

2019, 39(11): 1198-1202. doi:10.15918/j.tbit1001-0645.2019.222

Abstract(959) PDF(347)

Abstract:
In order to solve the problem of active user equipment detection and channel estimation in massive machine-type communications(mMTC)uplink transmission,a distributed multiple measurement vector subspace pursuit(DMMV-SP)algorithm was proposed in this paper. Firstly,a grant-free massive random access scheme was adopted to reduce the latency and signal overhead of mMTC. Secondly,considering the multi-carrier transmission scheme and combining the subspace pursuit algorithm,the structural sparsity of the receiving antennas and sub-carriers were utilized for the active user equipment detection and channel estimation simultaneously. Finally,the active user equipment detection and channel estimation performance were evaluated by calculating the error probability and the mean square error. The simulation results show that the proposed DMMV-SP algorithm can achieve better results than the traditional orthogonal matching pursuit(OMP)algorithm.

A Concept of Satellites’ Health Management Based on TDRS SMA

SUN Bao-sheng, CAO Zheng-rui, DING Hua

2019, 39(11): 1203-1206. doi:10.15918/j.tbit1001-0645.2019.226

Abstract(892) PDF(314)

Abstract:
In order to satisfy the requirements, using tracking and data relay satellite system (TDRSS) at anytime and anyplace, for the monitor of intellectualized satellites health management, a concept of satellites' health management was proposed based on tracking and data relay satellite(TDRS)S-band multiple access (SMA). The new system was arranged to be composed of the TDRS, terminal equipments on satellites, and the ground equipments. A working process of health management was designed, including health information transmission, controlling SOS satellites quickly and solving the question three periods. Some key technologies were carried out for the new system, mainly including satellites' health management, panoramic beam and space network access based on TDRS SMA. The new mode can provide a new approach for the development of TT&C by subsequent TDRSS.

Simultaneous Determination of Tween 20 and Synthetic Capsaicin for New Type of SC-Sprays by HPLC-UV-ELSD

SUN Li-quan, YANG Xue-dong, SUN Chen-yu, TANG Bo, LUO Ai-qin

2019, 39(11): 1207-1210. doi:10.15918/j.tbit1001-0645.2018.334

Abstract(964) PDF(372)

Abstract:
To simultaneous determination of synthetic capsaicin (SC) and Tween 20 in SC-sprays for police use, a HPLC-UV-ELSD method was developed. The SC and Tween 20 were successively detected by the UV detector and ELSD detector combined in one HPLC system. The chromatographic conditions were optimized as follow:the mobile phase was methanol and water (80:20), flow rate was 1.0 mL/min, UV wavelength was 280 nm, and the column temperature was set at 28℃. The flow rate of air of ELSD was maintained at 2.5, the pressure was 0.5 MPa, and the temperature of tube was kept at 60℃. The calibration curves built with the mixing standard were linear in the ranges of 196~980 μg/mL for SC,and 212~1 060 μg/mL (R²>0.999) for Tween 20. Results show that, the recoveries can be obtained in the range of 90%~110%. This developed method has been demonstrated to be suitable for determining the real filling agents in SC-sprays for police use.

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