bob手机在线登陆学报自然版

2017, 37(5): .

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2017, 37(5): .

Abstract(552) PDF(763)

Abstract:

Characteristics of Hydraulic Transformer Controlled Hydraulic Motor System

ZHAO Hong-mei, WU Wei, HU Ji-bin, YUAN Shi-hua, DI Chong-feng

2017, 37(5): 441-445. doi:10.15918/j.tbit1001-0645.2017.05.001

Abstract(1201) PDF(1506)

Abstract:
To the hydraulic transformer controlled hydraulic motor system, the system transfer function was built based on the system principle, dynamic equation and the linear theory. Theoretical analyzing indicates that the hydraulic transformer controlled hydraulic motor system has minimum phase system characteristic and non-minimum phase system characteristic simultaneously. For the hydraulic transformer with equivalent port, when the hydraulic transformer control angle is less than 30°, the system is the minimum phase system, and when the hydraulic transformer control angle is more than 30°, the system is the non-minimum phase system. Based the hydraulic transformer controlled hydraulic motor system dynamic equations,the simulation result proved that when the hydraulic transformer control angle is more than 30°, the step response of system shows negative response and the characteristics of the non-minimum phase system. The experiment studies validate the results of the theoretical analysis and simulate analysis further. The research indicates that the hydraulic transformer controlled hydraulic motor system is not suitable for the high precision torque and speed control system.

Thermo-Gravimetric Characteristics of Particulate Matter Emitted from a Diesel Engine Equipped with a Non-Thermal Plasma Equipment

GAO Jian-bing, MA Chao-chen, XING Shi-kai, LIU Jiang-quan, SUN Li-wei, GE Yun-shan

2017, 37(5): 446-450,496. doi:10.15918/j.tbit1001-0645.2017.05.002

Abstract(1431) PDF(1188)

Abstract:
A non-thermal plasma (NTP) reactor was designed based on corona discharge to reduce the particulate matter (PM) emitted from a diesel engine. Raw PM, PM escaped from NTP reactor, and PM aggregation sampled at 100% engine load were used to perform the thermo-gravimetric (TGA) experiments after being volatilized the VOC contained in PM. The activation energy was calculated based on the results of TGA experiments. The results show that the profiles of PM pre-treatment present double peaks phenomenon. The peak point of pre-treatment profiles of PM escaped from NTP reactor moves to higher temperature compared to raw PM. The oxidation temperature of PM aggregation is higher than raw PM while it is lower for PM escaped from NTP reactor. The calculated activation energy of PM escaped from NTP reactor is the highest among the samples.The activation energy calculated using KAS method is lower than that using single-ramp rate method and the difference is enlarged when increasing the ramp rate of single-ramp rate method.

A Fault Diagnosis Method Based on Sparse Coding for Hydraulic Pump

WANG Peng-fei, WANG Xin-qing, ZHU Hui-jie, LI Yan-feng, ZHANG Mei-jun

2017, 37(5): 451-454,465. doi:10.15918/j.tbit1001-0645.2017.05.003

Abstract(1050) PDF(967)

Abstract:
Due to the problems existing in the process of hydraulic pump fault diagnosis, the difficulty and the complexity to extract weak feature of the failure hydraulic pump and to automate, a sparse coding method was proposed for the hydraulic pump fault diagnosis. Firstly, the vibration signals were demodulated and transformed to frequency domain, then the K-SVD algorithm was used to obtain the dictionary from the learning of training samples, at last, the orthogonal matching pursuit algorithm was used to decompose and reconstruct the test signals. The classification of the failure of the hydraulic pump was achieved according to the reconstruction rate of the testing signal in different types of dictionary. Compared with BP neural network and support vector machine (SVM), the proposed sparse coding method shows a faster recognition speed, higher accuracy and better stability, and it can realize the fault diagnosis of hydraulic pump effectively.

Bounded Tracking Control of Ammunition Transfer Manipulators with Chassis Oscillation

GUO Yu-fei, HOU Bao-lin

2017, 37(5): 455-460. doi:10.15918/j.tbit1001-0645.2017.05.004

Abstract(915) PDF(948)

Abstract:
Dynamics of ammunition transfer manipulators is strongly affected by nonlinear forces due to the oscillation of the chassis, resulting in poor positioning accuracy of the ammunition. Traditional PID controller ignores the uncertain disturbance caused by the chassis vibration, and shows the problems of high control gains and actuator saturation. In this paper, a new tracking control approach was proposed based on the computed torque method and an implicit Lyapunov based control. Being differentiable functions of error variables of the system, the controller's gains can increase and tend to zero as the actual trajectory approximating to the desired trajectory, but the control force can always satisfy the given constrain.The dynamic equation of the system was solved with Newton's method and Runge-Kutta method. Results demonstrate that the controller greatly compensates the effects of the chassis oscillation, can fulfill the accurate tracking control of the ammunition transfer manipulator, and show good robustness.

Static Gait Optimization Method for Quadruped Robot Based on Particle Swarm Optimization Algorithm

HAN Bao-ling, ZHAO Rui, LUO Qing-sheng, XU Feng, ZHAO Jia-heng

2017, 37(5): 461-465. doi:10.15918/j.tbit1001-0645.2017.05.005

Abstract(1310) PDF(1245)

Abstract:
Focusing on static gait planning problem when the quadruped robot was adjusting laterally, a new method based on particle swarm optimization (PSO) was proposed to optimize the lateral adjustment parameter. The design variable was the body lateral adjustment parameter in motion. Stability, linearity and other motion performances were considered comprehensively in the objective function. Besides, the simulation experiments were carried out to verify the proposed optimization method in Matlab and Adams. Experimental results show the searching of global optimal parameters can be done quickly and efficiently by the proposed algorithm, such that the robot can achieve a good performance during static gait.

Reconfiguration Plan Evaluation Based on Preference Ranking of Key Characteristics in Reconfigurable Manufacturing System

WANG Guo-xin, HUANG Si-han, SHANG Xi-wen, YAN Yan, DU Jing-jun

2017, 37(5): 466-472. doi:10.15918/j.tbit1001-0645.2017.05.006

Abstract(1062) PDF(898)

Abstract:
In order to develop a quantitative evaluation index model for the essential characters of RMS (reconfigurable manufacturing system) and to optimally select the configuration plans with their outstanding advantage and disadvantage comparison, an evaluation method was proposed based on PROMETHEE (preference ranking organization method for enrichment evaluation). Analyzing the reconfiguration of the reconfigurable machine tool and manufacturing cell, a basic evaluation index and the quantitative model was designed to take the key characters of RMS, scalability, convertibility, diagnosability, modularity, integrability and customization. AHP (analytic hierarchy process) was used to assign the weight for these indexes. In the evaluation process, PROMETHEE I was applied firstly to analyze the advantage and disadvantage for each alternative plan. Secondly, PROMETHEE Ⅱ was adopted to analyze the comprehensive advantage. Finally, the sequence of alternative plans was decided based on the analyzed results. A case study from a shop floor of an institute was presented to validate the effectiveness and practicability.

Transient Fuel Consumption Modelling Based on Transient Correction

JIN Hui, ZHOU Min, LI Shi-jie

2017, 37(5): 473-477,484. doi:10.15918/j.tbit1001-0645.2017.05.007

Abstract(1242) PDF(1588)

Abstract:
Fuel consumption models have emerged as an effective tool for the development and assessment of new vehicle technologies. However, most existing fuel consumption models are based on steady-state fuel consumption map. They are not able to precisely predict vehicle fuel consumption under transient conditions. To solve this problem, a transient fuel consumption model called BIT-TFCM was developed by introducing appropriate transient corrections based on the steady-state fuel consumption models. The BIT-TFCM model was validated with experimental data. And the results show that the model accuracy can be improved significantly by introducing transient corrections. The mean absolute percentage error of the BIT-TFCM is approximately 11.44%~19.28% lower than that of steady-state model. Moreover, the prediction results of the BIT-TFCM model are more accurate than the classic VT-Micro model.

Design of Hybrid Energy Storage System for Power-Split Hybrid Electric Vehicle

ZHANG Lin, ZENG Xiao-hua, Guo Kong-hui, WANG Yang, ZHANG Ce, SONG Da-feng

2017, 37(5): 478-484. doi:10.15918/j.tbit1001-0645.2017.05.008

Abstract(1009) PDF(1292)

Abstract:
To solve the problems of short cycle life and small power density of single battery energy storage system in hybrid electric vehicles (HEV), a battery-ultracapacitor hybrid energy source was proposed. Then, the model of battery pack and ultracapacitor in parallel connection was established based on AVL-Cruise/Simulink, and a hybrid energy storage system control strategy was joined in energy management strategy of the best engine running condition. The hybrid energy storage control strategy was designed to relax the shocking of large current to the battery when starting and braking engine, to make the battery work in a high efficient range so as to improve the vehicle fuel economy. On this basis, battery and ultracapacitor parameters were matched. And the simulation results show that large current charge-discharge of battery pack can be reduced obviously, and the fuel economy of HEV can be improved as well.

Shifting Control of Heavy-Duty Planetary Transmission

WANG Er-lie, CHEN Hui-yan, GU Hong-tao, WANG Hong-liang

2017, 37(5): 485-490. doi:10.15918/j.tbit1001-0645.2017.05.009

Abstract(1311) PDF(1232)

Abstract:
To improve the vehicular shift quality and the heavy off-highway vehicle's performance, the vehicular equipped heavy-duty planetary transmission was analyzed, and a kinematic model of the testing automatic transmission with three degree of freedom was established. Then a shift control strategy was developed based on analyzing for the electro-hydraulic control system of the automatic transmission, and taking the shift clutch slipping which fused the turbine speed and the transmission output shaft speed as the control parameters. The difference of the vehicular acceleration, measured by a fiber optic gyroscope installed in the vehicular crew cabin, was used to evaluate the shift quality. Finally, the proposed control strategy was thoroughly verified on a heavy off-highway vehicle, excellent shift quality was achieved with the experimented data. And the contrast test show that the shift control quality by the clutch slipping is better than that controlled with the turbine speed.

Driving Rule Acquisition and Decision Algorithm to Unmanned Vehicle in Urban Traffic

CHEN Xue-mei, TIAN Geng, MIAO Yi-song, GONG Jian-wei

2017, 37(5): 491-496. doi:10.15918/j.tbit1001-0645.2017.05.010

Abstract(1786) PDF(2921)

Abstract:
Lane-changing decision of multi-source information on the urban traffic environment is the key technology to unmanned vehicles achieve actual road driving, to extract the driver's lane-changing decision rules in the complex and dynamic environment, firstly, PreScan software was used and virtual urban traffic environment was built, 6-DOF vehicle dynamics model was based on the Simulink, the decision rules of driver lane-changing behavior was extracted through rough set. The results show that the relative speed of the experimental vehicle and leading vehicle maintains at around 4~7 m/s, and when the space distance between adjacent cars reaches 20~35 m, the driver begins to implement lane-changing, the results provide driving knowledge for unmanned vehicles online machine learning and theoretical basis for the depth study of lane-changing behavior of uncertain decision-making.

Gate Leakage Current Conduction Mechanisms in NO Annealing and Dry Gate Oxides Grown on 4H-SiC

LIU Li, YANG Yin-tang

2017, 37(5): 497-500. doi:10.15918/j.tbit1001-0645.2017.05.011

Abstract(1184) PDF(1451)

Abstract:
Current conduction mechanisms of SiC MOS capacitors on n-type 4H-SiC with or without NO annealing were investigated in this work. Results show that FN tunneling is the dominate current conduction mechanism in the high electrical field, and the barrier height is 2.67 eV and 2.54 eV respectively for experiencing NO annealing and without NO annealing. A higher barrier height for NO annealing sample indicate the effect of N element on the SiC/SiO₂interface quality. In intermediate oxide electrical field, instead of Trap-assisted tunneling PF emission dominate the current conduction in this region. And the C-V characteristics also show the advantages of NO annealing on the SiC/SiO₂characteristics. This work will provide significant foundation for the key processing technology of SiC MOS device.

Fully Differential Mixed Mode Biquadratic Filter Based on FDCFOA

WANG Chun-yue

2017, 37(5): 501-505. doi:10.15918/j.tbit1001-0645.2017.05.012

Abstract(905) PDF(1115)

Abstract:
A mixed mode biquadratic filter was presented based on fully differential current feedback operational amplifier(FDCFOA). Compared with available CFOA circuits, the proposed filter circuit can reduce total harmonic distortion greatly(THD is 3.6% at 1 MHz of 100 mV input voltage). The FDCFOA filter can realize fully differential input and output voltage mode(VM) and current mode(CM) low pass, high pass and band pass functions without changing circuit configuration simultaneously. The natural frequency can be adjusted independently without affecting quality factor, and the sensitivities are low. PSPICE simulations are completed using 90 nm CMOS technology, theoretical analysis and simulation results verify the availability of the presented circuit.

Network Coding Transmission Performance Under the NDN Protocol

HAN Xiao-dong, GAO Fei, WANG Ai-hua

2017, 37(5): 506-510. doi:10.15918/j.tbit1001-0645.2017.05.013

Abstract(969) PDF(1237)

Abstract:
The current era of information explosion makes the emergence of massive data, data transmission rate is growing exponentially, for NDN (named data networking) network specific amount of computing and large data storage, tradition internet architecture has been unable to meet the performance needs of large data networks. Delay is an important parameter to measure network performance merits, network coding can reduce network latency under the premise of guaranteed throughput. A network coding was introduced in NDN network, in order to resolve that network transmission performance problems under NDN transfer protocol, focusing on the two network performance parameters with latency and throughput. Experimental results demonstrate that the NDN combined with network coding can ensure high network throughput which multicast route can't attain, simultaneously reduce network latency with 50%, improve network performance, save the cost of network consumption, meet the current requirements of handling big data services.

Optimized Pilot Placement for Compressive Sensing Based on Sparse Channel Estimation in OFDM Systems

XUE Yan-ming, PENG Yun-ke, GAO Fei

2017, 37(5): 511-514. doi:10.15918/j.tbit1001-0645.2017.05.014

Abstract(1000) PDF(1442)

Abstract:
The pilot pattern problem for sparse channel estimation in orthogonal frequency division multiplexing (OFDM) systems has been examined. To optimize the performance of sparse channel estimation, an optimized algorithm was proposed. The algorithm was based on minimizing mutual coherence of the measurement matrix in CS theory, to group with increasing the generated random number. The mutual coherence value of each group was calculated, and compared to get the maximum mutual coherence value, consequently to optimize the pilot pattern. Simulation results demonstrate that the pilot pattern obtained using the proposed algorithm can get 30%lower mean square error(MSE)compared with the original pilot pattern.

Improved Double Block Zero Padding Algorithm for P Code Direct Acquisition

XIONG Zhu-lin, AN Jian-ping, WANG Ai-hua

2017, 37(5): 515-520,550. doi:10.15918/j.tbit1001-0645.2017.05.015

Abstract(908) PDF(1359)

Abstract:
A segmented rotation double block zero padding (DBZP) algorithm was proposed based on the improved traditional DBZP algorithm for direct acquisition of P code in the environment of heavy noise and large frequency dynamics. The input complex-valued baseband signal was first segmented into finite-length records, and then transformed into frequency coefficients by fast fourier transform (FFT). By estimating the initial value of the frequency offset and its slew, the center frequency offset was determined for each temporal record, which was then compensated by cyclically shifting the corresponding Fourier coefficient record. Once the compensation was done, the correlation between the input signal and the local PN code was performed in frequency domain, and the correlation output was non-coherently accumulated over a number of records. For the last step, the constant false alarm rate (CFAR) detection and parabola interpolation were utilized with the maximum value of the accumulated correlation output. It is found for typical acquisition scenario that the presented algorithm may cut down computational overhead, memory consumption and the mean acquisition time by 64%, 99% and 80%, respectively, in comparison with traditional DBZP algorithm, without noticeable SNR penalty. The principles for choosing key parameters of the algorithm are discussed to meet various practical requirements.

Dual Frequency Single Epoch Integer Ambiguity Rounding Resolution Algorithm for Ultra-Short Baseline

LIU Shuo, ZHANG Lei, LI Jian, LONG Teng

2017, 37(5): 521-525. doi:10.15918/j.tbit1001-0645.2017.05.016

Abstract(1305) PDF(1534)

Abstract:
Carrier phase differential GPS has been widely used in ultra-short baseline situation such as orientation, attitude determination and deformation monitoring. Carrier phase integer ambiguity resolution is the key issue. It is efficient to round wide lane integer ambiguity by pseudo-range. However, the rounding error for one cycle wide lane integer ambiguity always happens, and when pseudo-range error is large, it may be more than one cycle error. In this work, an integer ambiguity resolution algorithm was designed to offset the wide lane integer ambiguity rounding error. One cycle wide lane integer ambiguity error was detected and fixed by the fractional part ofL₁float solution separated from wide lane. The wide lane integer ambiguity error beyond one cycle was excluded by RAIM algorithm. The whole integer ambiguity was solved by the baseline vector which was calculated by partial right integer ambiguity. Some field tests were carried out based on GPS ultra-short baseline. Results show that, the designed algorithm increases the success rate of directly rounding wide lane integer ambiguity. The success rate is slightly lower but the computational efficiency is much higher compared to single epoch LAMBDA algorithm.

Time-Varying Multi-Target Tracking Method Based on Particle Filter in Radio Tomographic Network

LIU Heng, NI Ya-ping, WANG Zheng-huan, XU Sheng-xin, BU Xiang-yuan, AN Jian-ping

2017, 37(5): 526-531. doi:10.15918/j.tbit1001-0645.2017.05.017

Abstract(999) PDF(1022)

Abstract:
Traditional method based on radio tomographic image (RTI) suffers from latency, resulting in the existence of a lag between the estimated target number and the true one. Moreover, the tracking accuracy of the traditional method should be improved. In this paper, a particle filtering (PF) theory was introduced for time-varying multi-target tracking (MTT) in radio tomographic network, utilizing the particles with variable dimensions to estimate the target number and track the targets to solve the latency problem and improves the tracking accuracy. Some experiments were conducted in a monitored region with the area of 9.5 m×9.5 m to verify the effectiveness of the PF-based method. The experimental results show that the optimal sub-pattern assignment (OSPA) error of traditional method is 0.485 m. In contrast,the OSPA error of proposed method is 0.362 m, which is improved by 25%.

Machine-Driven Integrated Scheduling Algorithm with Equipment' Idle Adjustment

XIE Zhi-qiang, LI Zhi-ning, XUE Jian, XIN Yu

2017, 37(5): 532-536. doi:10.15918/j.tbit1001-0645.2017.05.018

Abstract(1012) PDF(657)

Abstract:
To solve the problem that general integrated scheduling algorithm based on machine-driven ignored the idle time of the machine due to the time difference between the end time of the process and the start time of the non-schedulable process, a machine-driven integrated scheduling algorithm with equipment' idle adjustment was presented. In order to operate the non-schedulable process in advance and reduce the waiting time of equipment' idle, a shortest path for the non-scheduling process was developed, making the processes in the path be operated firstly and the precedence activities be completed as soon as possible. Results show that, the proposed algorithm can make waiting time shorten effectively and improve equipment utilization.

Inferring Refactoring Intention from Test Case Modification

GAO Yuan, LIU Hui, FAN Xiao-zhong, NIU Zhen-dong

2017, 37(5): 537-543. doi:10.15918/j.tbit1001-0645.2017.05.019

Abstract(1038) PDF(956)

Abstract:
Existing tools/methods are used to infer refactoring according to production code change in traditional development mode. In the test-driven development (TDD), there are few tools can be used to guide test driven refactoring. In this paper, an approach was proposed to inferring refactoring intension from test case modifications. Firstly, the test code modification was captured with a monitor, and then the potential refactoring was inferred from the captured modification according to predefined heuristics. The proposed approach has been implemented and evaluated with two real applications. Evaluation results show that compared with existing approach the precision increases by 15% and the recall increases by 33.3%~42.8%.

Auto-Vectorization Method Based on Dynamic Programming

LÜ Peng-wei, LIU Cong-xin, ZHAO Yi-ming, SHEN Xu-bang

2017, 37(5): 544-550. doi:10.15918/j.tbit1001-0645.2017.05.020

Abstract(1106) PDF(1194)

Abstract:
As SLP (super-word level parallelism) auto-vectorization algorithm will lose some vectorization opportunities by using heuristic strategy, an auto-vectorization method named DPSLP that based on dynamic programming was proposed in this paper. In this method, the candidate statement groups were searched for SIMD (single instruction multiple data) instruction by using more aggressive strategy than SLP, and the optimal statement groups were selected to vectorize according to the cost of which calculated by dynamic programming formula. Experimental result show that DPSLP achieves on average a total decrease of 8% in execution time, 10% in static instruction cost and increase of 66.4% in vector width, compared with SLP.

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