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2020, 40(9): .

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2020, 40(9): .

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Theoretical Modeling and Performance Study on Erection Device with Gas-Squeezer Type Auxiliary Power Source

REN Yu-liang, GAO Qin-he, ZHOU Wei, FENG Jiang-tao, LIU Zhi-hao

2020, 40(9): 915-923. doi:10.15918/j.tbit1001-0645.2019.220

Abstract(2266) PDF(1381)

Abstract:
In order to reduce the erection time and the installed power of vehicle borne missile launcher, a rapid erection scheme was proposed based on gas-squeezer auxiliary power source. A mathematical model of the erection progress was presented to couple the mechanical, fuel gas and fluidic equations. The interior ballistics equation of gas generator was solved by Matlab/Simulink, and the simulation models of the squeezing tank,the hydraulic components and the mechanical device were built in AMESim. A prototype test of the gas generation device was carried out, to validate the co-simulation model. Based on the simulation results, the gas-squeezer system was compared with traditional pump-type system. The results show that the erection progress of the gas-squeezer system can be achieved within 34.5 s, shortened by 42.5%, and the installed power is only 11.6 kW, decreased by 38.9%. The new system can greatly increase the erection speed and reduce the system power.

The Adaptability of the RDE Window Method for Actual China Road

GE Yun-shan, WANG Ya-chao, DONG Hong-lei, SONG Bin, YIN Hang, LI Ze-lin, YANG Zheng-jun

2020, 40(9): 924-928. doi:10.15918/j.tbit1001-0645.2019.054

Abstract(2404) PDF(1306)

Abstract:
The portable emission measurement system (PEMS) devices for real driving emissions (RDE) test can eliminate the compliance of emission standards in a special laboratory which can more accurately reflect the emission level of the vehicle in real driving, providing an efficient method for determining vehicle emission defects. In this study, a gasoline vehicle was tested many times using PEMS in accordance with the RDE test procedure to analyze the relationship between the vehicle driving features and CO₂window normality. Results show that, the CO₂result is correlated with the speed and acceleration distribution of the vehicle in real driving. In the RDE test, it is found that when the acceleration distribution is consistent separately with WLTC low, high and superhigh acceleration distribution, the RDE can easily to pass the normality verification. And then, a one-to-one correspondence was produced about the driving features between RDE and WLTP Test, including urban to low speed interval, rural to high speed interval and motorway to extra-high speed interval. Finally, the coefficients of reference pointsP₁、P₂、P₃were established to make the legislation more suitable for China's real driving.

Abnormal Increase of Oil Level in Gasoline Direct Injection Engine at Freezing Area

ZHANG Fu-jun, ZHANG Lu-xing, WU Ping, WU Hao

2020, 40(9): 929-934. doi:10.15918/j.tbit1001-0645.2019.190

Abstract(2180) PDF(1363)

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The increase of oil level is a problem of gasoline direct injection engine at freezing area. The research was carried out to study the mechanism and solution of the problem. Selecting some test vehicles from three different manufacturers,the outdoor experiments were carried out in Heihe district. In the experiment, the change of oil level, oil temperature and cooling water temperature were recorded. Taking the oil level height and oil level rise rate as criterion to evaluate the influencing factors of oil level rise, the main influencing factors of oil level rise were analyzed separately through variable control. The results of the experiment show that the fuel injection mode and temperature rise speed of engine are main reasons of the rise of oil level. The increase of injection times and engine temperature rise speed can reduce the rise rate of oil and speed up the oil level to balance.

Research on Cam Driven Hydraulic Fully Variable Valve Mechanism

LIU Bo-lan, YU Xi-yang, WANG Xiao-gang, YAN Chao, YU Fei, WANG Wen-tai, HAN Yao-hui

2020, 40(9): 935-940. doi:10.15918/j.tbit1001-0645.2019.228

Abstract(2119) PDF(1284)

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At present, the electro-hydraulic variable valve is the development trend of variable valve technology. However, most electro-hydraulic variable valves require high-responsiveness solenoid valves, which are costly and complex to control. Besides, VVT and VVL technologies, which are mature and widely used in the market, are limited and hierarchical in regulating valve parameters. To solve the problems, a cam-driven variable hydraulic valve mechanism was developed and the bench test was carried out. The results show that, the designed mechanism can achieve full continuous variable of open angle, close angle and valve lift. And the cost of the system is lower and its control operation is convenient.

The Motor-Driven Still Hold System for Electric Vehicle on Slope

LI Gui-qiang, WU Zheng-bin, JIANG Fan, LIN Xiang-hui, WU Li-qiang

2020, 40(9): 941-948. doi:10.15918/j.tbit1001-0645.2019.230

Abstract(2055) PDF(1275)

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The traditional slope parking is realized based on the friction force of brake system. There is a possible impact or backsliding risk because of the delay or advance of parking braking force release during start process. To solve those problems, a slope motor-driven still hold (MSH) system was proposed for electric vehicles. A dynamic model of MSH system was established based on the parameters of the driving motor system. For the uncertainty of slope and vehicle mass parameters in MSH system, a parameter identification-disturbance rejection control strategy was proposed. The parameter identification was used as the initial input value of the controller, and the disturbance rejection control technology was used to compensate the identification error. Experimental results demonstrate that, the variable forgetting factor least square method can estimate the slope and vehicle mass parameters, and the error is within 15%. In addition, the active disturbance rejection control (ADRC) can eliminate those error and disturbance. Compared with the traditional PI controller, it possesses the advantages of short backward displacement and rapid response speed.

Experiment Research on HMI Usability Test Environment Based on Driving Simulator

LIU Yu-jia, WANG Jian-min, WANG Wen-juan, ZHANG Xiao-long

2020, 40(9): 949-955. doi:10.15918/j.tbit1001-0645.2019.176

Abstract(2203) PDF(1285)

Abstract:
In view of the limitation of the existing vehicle simulators, the problems were analyzed in this paper, including the usability test environment for the test of automobile human machine interface (HMI), the usability test methods of the automobile HMI on a driving simulator. Taking advantage of the current development of the intelligent and network-linked function of the car, a car bench on a smart cockpit was designed and built to achieve the general intelligent vehicle driving simulation, so as to make the HMI testing process more refined, and verify the feasibility and validity of the design method. And then, the LDW (lane departure warning) function of the advanced driving assistance system was set as an example to analyze the application scenario of LDW. Finally, the HMI design was applied to a driving simulator for usability testing, intending to bring some inspiration to the future HMI test methods.

Cable Assembly Sequence Planning Based on Chaos-Particle Swarm Optimization

YANG Xiao-dong, LIU Jian-hua, MA Jiang-tao, ZHAO Ying-feng, LÜ Nai-jing

2020, 40(9): 956-962. doi:10.15918/j.tbit1001-0645.2019.243

Abstract(2243) PDF(1289)

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To solve the problem of automatic assembly sequence planning of flexible cables in complex electromechanical products, a new method was proposed for assembly sequence planning of flexible cables based on improved particle swarm optimization. Firstly, the constraint conditions of cable assembly were determined. On this basis, a mathematical model of cable assembly sequence planning was established with priority of cable assembly, cable length, diameter, bending radius and number of branches as comprehensive optimization objectives. Then the standard particle swarm optimization algorithm was discretized to make it suitable for assembly sequence planning. On this basis, the initialization of assembly sequence and the search strategy of the algorithm were improved respectively. Finally, the proposed algorithm was applied to the cable assembly sequence planning process of a certain type of satellite structure plate, verifying its feasibility and computational efficiency.

A Low-Cost Location System Based on Deep Learning for Stacked Materials Sorting

TIAN Li-xun, LIU Xiong-fei, ZHANG Cai-qin, WANG Wen-jia, FU Jian-zhong

2020, 40(9): 963-969. doi:10.15918/j.tbit1001-0645.2019.238

Abstract(2238) PDF(1324)

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To improve industrial production efficiency, a low-cost location system based on deep learning was proposed for stacked materials sorting. Firstly, taking the images got from monocular optical cameras as the input data, a one-stage detection method was used to obtain the candidate objects. Then, a deep convolution neural network was used to classify the adjacent ROIs of objects to filter the possible candidates. Finally, some interest images of the filtered candidates were processed to get the key shape and location of the object. Since the robustness of the algorithm and without the use of the expensive depth camera, the new method can reduce hardware cost and improve detection accuracy.The test results in the real scene show that the location error of the new system can be reduced to less than 0.3 cm.

The Effect of Morphology Characteristics of CFRP/Al Single Lap Joints on Bonding Properties

CHEN Xiao-kai, FU Dong, SUN Ling-yu, LI Meng-qiang

2020, 40(9): 970-974. doi:10.15918/j.tbit1001-0645.2019.066

Abstract(2042) PDF(1240)

Abstract:
The multi-material structures is one of the effective technical approaches to realize vehicle weight reduction, and the technical difficulty is the connection between heterogeneous materials. For the CFRP/Al single-lap joints, based on the cohesive force model, one finite element analysis model was established, and the effectiveness of the finite element model was verified through experiments. Three CFRP/Al adhesive joints with different morphological features were constructed, and the ultimate failure load and failure energy absorption under uniaxial tensile load were used as performance indicators. The results show that compared with the ordinary single lap joints, the arc joint damage load and energy absorption are reduced by 11.3% and 9.88%, respectively. Although the failure load of rectangular slot joints has been reduced, but due to the more effective use of the middle region of the adhesive layer, the joint energy absorption characteristics have been greatly improved, and the joint impact resistance performance has increased by 91.63%.

Equivalent Circuit Model for Field-Line Coupling Inside a Rectangular Enclosure with Electrically Large Apertures

ZHANG Ya-pu, WANG Jian-tao, WANG Dong-feng, LI Mi-na, GU Hong, ZHOU Zhong-hua

2020, 40(9): 975-981. doi:10.15918/j.tbit1001-0645.2018.191

Abstract(2451) PDF(1255)

Abstract:
A novel equivalent circuit model for field-line coupling analysis inside an enclosure with electrically large apertures was proposed in this paper. Firstly, the electric field inside the enclosure was calculated based on Cohn model and mirror image principle. Secondly, a scalar quantity Green function was deduced for electric dipole radiation field inside an enclosure, an integral equation for field-line coupling was expanded in series, and then a matrix equation was obtained, based on which the equivalent circuit model was established. Finally, the boundary condition of the transmission line was considered to compute the terminal response current, and a simulation analysis was carried out for the response current of the transmission line inside a cavity illuminated by a plane wave (ϕ=0,θ=0,φ=π/2). The results of 5 verification tests shows that:the precision of the equivalent circuit model is inversely proportional to transmission line exponentη, and whenη=0.375, the correlation coefficientρ=0.987 8. The ratio of the consuming time is 1:9.2 for 1 001 samples in a frequency range of 0~3 GHz, verifying the efficiency of equivalent circuit model. The correlation coefficient is up to 0.984 4, while the mean of absolute error and the standard deviation of this method compared to TLM are 12.445 dBA and 16.438 dBA, verifying the accuracy of equivalent circuit model.

Approximate Message Passing Based Multiuser Detection for Media Based Modulation

SONG Wei

2020, 40(9): 982-987. doi:10.15918/j.tbit1001-0645.2020.038

Abstract(1992) PDF(729)

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To meet the demands, low complexity and high accuracy, of multi-user detection in media based modulation (MBM), an approximate message passing (AMP) based multi-user detection algorithm was proposed. Because of the sparsity of MBM, a sparse signal reconstruction method based on compressed sensing was used for multi-user detection. The method was arranged that, when the observation matrix satisfied the condition of independent and identical distribution in the process of multi-user detection, the AMP algorithm could guarantee the performance of high precision detection and further reduce the detection complexity. At the same time, in the case of unknown noise variance, setting up the steps of estimating noise variance based on expectation maximization method, the proposed algorithm was more suitable for the actual scene. The simulation results show that the proposed multi-user detection algorithm based on AMP can provide a best performance compared with traditional multi-user detection methods and other multi-user detection methods with similar complexity.

Study on Predistortion Algorithm of Spaceborne High Rate Modulator

WANG Chang-hong, GAO Fei, DU Wei

2020, 40(9): 988-993. doi:10.15918/j.tbit1001-0645.2019.099

Abstract(2050) PDF(1267)

Abstract:
In order to meet the demand of high rate communication services in the spaceborne high rate data transmission system,the new digital modulation systems (such as OFDM, M-QAM, etc.) are increasingly used, but the resulting nonlinear effect of the power amplifier is also becoming more serious, which has a great impact on the performance of the demodulator. The traditional digital predistortion algorithm is not suitable for the spaceborne high rate data transmission system with strict resource limitation due to its slow convergence speed and higher computational complexity. In this study, a recursive least squares algorithm based on QR decomposition (QRD-RLS) was proposed. The theoretical analysis and performance simulation of the algorithm were carried out. Compared with the traditional predistortion algorithm, the algorithm has the advantages of small steady-state error, fast convergence speed and low computational complexity. Based on the algorithm, a high rate modulator structure with predistorter was designed. The test results of 16QAM signal show that the predistortion scheme based on QRD-RLS can provide a significant compensation effect on the distortion signal, and the error vector magnitude (EVM) can be reduced from 7.4% to 2.5%, the out of band interference suppression can be increased by 10 dB.

Slope Climbing stability Analysis of Hexapod Robot with Eccentric Wheel Legs

LI Xiao-li, ZHANG Chao, ZHAO Yan-ling, ZHU Xiao-qing, XUE Ai-lin

2020, 40(9): 994-1001. doi:10.15918/j.tbit1001-0645.2019.080

Abstract(2073) PDF(1311)

Abstract:
In the current application of robots, the robot system is required to have a high adaptability to unstructured environment. In this paper, a hexapod robot with eccentric wheels was studied, and its basic mechanical structure was introduced. The motion model and mechanical constraints of the hexapod robot when climbing a slope were established based on the stable cone method. A wave-like climbing gait was designed. The most easily overturning posture of the robot in this motion mode was analyzed. Combining with its mechanical structure characteristics, the stability of the robot was verified by using the stable cone method. The critical slope angle of the robot during climbing was obtained and verified by simulation and physical experiments. In this mechanical structure and the use of the corresponding climbing gait, the robot can have better climbing performance. The maximum stable climbing angle of the robot can be measured in the experimental environment to be about 33 degrees.

A High Accuracy Method for Individual Assessment and Group Index Construction of Cyber Security Awareness

LI Rui, PAN Li-min, HAO Jing-wei, ZHANG Han-qing, LUO Sen-lin, WU Qian

2020, 40(9): 1002-1008. doi:10.15918/j.tbit1001-0645.2019.051

Abstract(2160) PDF(1261)

Abstract:
To achieve better results in the individual assessment and the group index construction of the cyber security awareness, a high-accurate method was proposed, combining with a set of different techniques. On the first stage, multi-dimension data acquisition and mixture of regression were introduced for the quantification of the security score. And then, gathering the extracted data with the improved label propagation algorithm, the awareness level was obtained based on the customized supervising data, being independent of tagged data. Furthermore, by using the Grubbs criterion to design the calculation function for group security index, to diminish the abnormal points and abstract the common features, the group index was constructed based on the evaluation results of cyber security awareness. Compared with the selected state-of-the-art counterparts, the proposed design can achieve a better accuracy and objectivity, and be able to demonstrate the general standard for the group security index. The results provide a effective method for the further study of the cyber security awareness.

Key Data Location Method for Fuzz Testing Based on Path Label and Data Mutation

JIAO Long-long, LUO Sen-lin, LIU Wang-tong, PAN Li-min

2020, 40(9): 1009-1017. doi:10.15918/j.tbit1001-0645.2018.086

Abstract(2171) PDF(1231)

Abstract:
Aiming at the problem of high resource consumption and false positive rate in current key data location methods for binary program fuzz testing, a new key data location method for fuzz testing based on path label and data mutation was proposed. First, a static analysis was used to locate the dangerous operations in the binary program. Then dynamic instrumentation was used to track the execution of program and obtain the path labels and parameters of dangerous operation. Finally, the position of key data was located by analyzing the tracking data before and after input data mutation. Experimental results show that this method can locate key data of input effectively under low resource consumption, the false positive rate is less than 0.3%, the recall is greater than 70%, and the precision is greater than 60%. This method can be used to improve the vulnerability detection ability of fuzz testing, possessing a strong practical value.

The Real-Time Imaging Method for Sliding Spotlight SAR Based on Embedded GPU

HU Shan-qing, LI Hui-xing, LI Bing-yi, XIE Yi-zhuang, CHEN Liang, CHEN He

2020, 40(9): 1018-1025. doi:10.15918/j.tbit1001-0645.2019.056

Abstract(2164) PDF(1318)

Abstract:
For the real-time SAR imaging systems, aiming at the problems of low real-time performance and high power consumption of traditional computing platforms, an implementation method was studied for embedded GPU. In order to make full use of the limited memory in the embedded GPU, a memory partitioning and reconfiguration scheme was proposed. The page-locked memory and zero-copy technology were used to realize the transmission-calculation parallelization. To achieve high real-time performance, large-scale parallelism was realized by using shared memory, registers, et. The result shows that sliding spotlight SAR imaging processing on the TX2 can only take 12.66 s time and consume 15 W power. This method is also applicable to other modes radar processing algorithms, and can provide reference for the future embedded real-time SAR imaging processing.

Radar Optimal Deployment Based on Graph Theory

SUN Hua-fei, ZHANG Shi-qiang, HE Meng-yuan, CHEN Jing-chao, LI Meng-meng, CAO Yue-qi

2020, 40(9): 1026-1032. doi:10.15918/j.tbit1001-0645.2018.371

Abstract(2083) PDF(1311)

Abstract:
In this paper, a radar deployment problem was translated into graph theory problem by some pre-processing operations, like discretization, to solve a multi-objective optimization problem for radar deployment based on graph theory knowledge. Firstly, different models were established according to various constraints and a corresponding algorithm was designed based on the state compression technology. Compared with traditional algorithms, this algorithm was arranged to be suitable for the solution of the radar deployment problems with more complicated constraints and area conditions, to present an optimal radar deployment scheme rapidly for different constraints. And then, some problems with factors of key area and redundancy were analyzed. Finally, the numerical simulations were carried out. The results show that, the proposed method can provide an optimal radar deployment scheme, which can not only cover whole area, but also minimize the redundancy and avoid resource consuming.

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2020 Vol. 40, No. 9

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